mcpls_core/bridge/translator/

dto.rs

//! Public MCP-facing result/data-transfer types returned by the tool-call
//! handlers in the sibling domain modules.

use std::num::NonZeroU32;

use schemars::JsonSchema;
use serde::{Deserialize, Serialize};
use thiserror::Error;

use super::enclosing::{ContextualDiagnostic, ContextualLocation, EnrichmentSummary};
use super::kind_filter::{self, KindFilter};
use crate::bridge::notifications::ReportedSeverity;
use crate::config::text_newtype::impl_text_newtype;
use crate::config::{BoundedText, InvalidBoundedText};
use crate::error::spelled_enum;
use crate::redaction::{Redactions, ServerText};

/// Convert an LSP integer-valued enum (`SymbolKind`, `CompletionItemKind`,
/// `InlayHintKind`, ...) to its wire-format `u32`.
///
/// Infallible and needs no fallback value, unlike a `serde_json` roundtrip.
pub(super) fn lsp_kind_to_u32<T: Into<u32>>(kind: T) -> u32 {
    kind.into()
}

/// Position in a document (1-based for MCP).
#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize, JsonSchema)]
pub struct Position2D {
    /// Line number (1-based).
    pub line: u32,
    /// Character offset (1-based).
    pub character: u32,
}

/// Largest line or character value a client may supply.
pub const MAX_POSITION_VALUE: u32 = 1_000_000;

/// Largest line span of a range given to a range-taking tool.
pub const MAX_RANGE_LINES: u32 = 10_000;

/// Why a client-supplied position was rejected.
#[derive(Debug, Clone, Copy, PartialEq, Eq, Error)]
pub enum InvalidPosition {
    /// A line or character below 1; positions are 1-based.
    #[error("Line and character positions must be >= 1")]
    ZeroBased,
    /// A line or character above [`MAX_POSITION_VALUE`].
    #[error("Position values must be <= {MAX_POSITION_VALUE}")]
    TooLarge,
}

/// Longest accepted `rename_symbol` `new_name`, in bytes.
///
/// No real identifier approaches this length in any language mcpls targets.
pub const MAX_NEW_NAME_LENGTH: usize = 1_000;

spelled_enum! {
    /// The client-supplied text fields that are validated as bounded text, named
    /// as they are on the wire.
    TextField {
        /// `new_name` of `rename_symbol`.
        NewName => "new_name",
        /// `trigger` of `get_completions`.
        Trigger => "trigger",
        /// `symbol_name` of a name-addressed tool.
        SymbolName => "symbol_name",
        /// `container` of a name-addressed tool.
        Container => "container",
    }
}

/// Why a client-supplied text field was rejected, and which one.
///
/// # Examples
///
/// ```
/// use mcpls_core::bridge::{NewName, TextField};
/// use mcpls_core::config::InvalidBoundedText;
///
/// let error = NewName::new("  ").unwrap_err();
/// assert_eq!(error.field, TextField::NewName);
/// assert_eq!(error.reason, InvalidBoundedText::Blank);
/// assert_eq!(error.to_string(), "`new_name` cannot be empty");
/// ```
#[derive(Debug, Clone, Copy, PartialEq, Eq, Error)]
#[error("`{field}` {reason}")]
pub struct InvalidTextField {
    /// The field that was rejected.
    pub field: TextField,
    /// The rule it broke.
    pub reason: InvalidBoundedText,
}

impl InvalidTextField {
    /// Tags a rejection with the `field` it was raised for.
    pub(crate) fn of(field: TextField) -> impl Fn(InvalidBoundedText) -> Self {
        move |reason| Self { field, reason }
    }
}

/// The name a `rename_symbol` call renames to: non-blank and at most
/// [`MAX_NEW_NAME_LENGTH`] bytes, so an unusable name is rejected before any
/// language server is asked.
///
/// # Examples
///
/// ```
/// use mcpls_core::bridge::NewName;
/// use mcpls_core::config::InvalidBoundedText;
///
/// assert_eq!(NewName::new("renamed")?.as_str(), "renamed");
/// assert_eq!(NewName::new("  ").unwrap_err().reason, InvalidBoundedText::Blank);
/// # Ok::<(), mcpls_core::bridge::InvalidTextField>(())
/// ```
#[derive(Debug, Clone, PartialEq, Eq, Deserialize)]
#[serde(try_from = "String")]
pub struct NewName(BoundedText<MAX_NEW_NAME_LENGTH>);

impl NewName {
    /// Validates `raw` as given; surrounding whitespace is kept.
    ///
    /// # Errors
    ///
    /// [`InvalidTextField`] naming `new_name` when `raw` is blank or longer
    /// than [`MAX_NEW_NAME_LENGTH`].
    pub fn new(raw: impl Into<String>) -> Result<Self, InvalidTextField> {
        BoundedText::new(raw)
            .map(Self)
            .map_err(InvalidTextField::of(TextField::NewName))
    }

    /// The name text, owned.
    #[must_use]
    pub fn into_string(self) -> String {
        String::from(self)
    }
}

impl_text_newtype!(NewName, InvalidTextField);

/// Longest accepted `get_completions` `trigger`, in bytes.
///
/// LSP defines `triggerCharacter` as a single character; 8 bytes covers any
/// one Unicode codepoint (at most 4 bytes in UTF-8) and short multi-character
/// triggers such as `->`, while rejecting anything that is not plausibly a
/// trigger.
pub const MAX_TRIGGER_CHARACTER_BYTES: usize = 8;

/// The text that triggered a completion request: not empty and at most
/// [`MAX_TRIGGER_CHARACTER_BYTES`] bytes.
///
/// Whitespace is a valid trigger (a space triggers completion in some
/// languages), so only the empty string is refused, not a blank one. That is
/// why it is not a [`BoundedText`], which refuses blank text.
///
/// # Examples
///
/// ```
/// use mcpls_core::bridge::CompletionTrigger;
/// use mcpls_core::config::InvalidBoundedText;
///
/// assert_eq!(CompletionTrigger::new("->")?.as_str(), "->");
/// assert!(CompletionTrigger::new(" ").is_ok());
/// assert_eq!(CompletionTrigger::new("").unwrap_err().reason, InvalidBoundedText::Blank);
/// assert!(CompletionTrigger::new("123456789").is_err());
/// # Ok::<(), mcpls_core::bridge::InvalidTextField>(())
/// ```
#[derive(Debug, Clone, PartialEq, Eq, Deserialize)]
#[serde(try_from = "String")]
pub struct CompletionTrigger(String);

impl CompletionTrigger {
    /// Validates `raw`.
    ///
    /// # Errors
    ///
    /// [`InvalidTextField`] naming `trigger` when `raw` is empty or exceeds
    /// [`MAX_TRIGGER_CHARACTER_BYTES`].
    pub fn new(raw: impl Into<String>) -> Result<Self, InvalidTextField> {
        let raw = raw.into();
        let invalid = InvalidTextField::of(TextField::Trigger);
        if raw.is_empty() {
            return Err(invalid(InvalidBoundedText::Blank));
        }
        if raw.len() > MAX_TRIGGER_CHARACTER_BYTES {
            return Err(invalid(InvalidBoundedText::TooLong {
                len: raw.len(),
                max: MAX_TRIGGER_CHARACTER_BYTES,
            }));
        }
        Ok(Self(raw))
    }

    /// The trigger text, owned.
    #[must_use]
    pub fn into_string(self) -> String {
        self.0
    }
}

impl_text_newtype!(CompletionTrigger, InvalidTextField);

/// Largest tab size a client may request for formatting.
pub const MAX_TAB_SIZE: u32 = 32;

/// Tab size used when a formatting request gives none.
const DEFAULT_TAB_SIZE: u32 = 4;

/// A tab size outside 1 to [`MAX_TAB_SIZE`].
#[derive(Debug, Clone, Copy, PartialEq, Eq, Error)]
#[error("tab_size must be between 1 and {MAX_TAB_SIZE}, got {0}")]
pub struct InvalidTabSize(pub u32);

/// The tab size a formatting request asks the server for: 1 to
/// [`MAX_TAB_SIZE`], 4 by default.
///
/// Deserializes from a JSON integer and rejects out-of-range values as
/// invalid params, so an unbounded `u32` never reaches a language server.
///
/// # Examples
///
/// ```
/// use mcpls_core::bridge::{InvalidTabSize, MAX_TAB_SIZE, TabSize};
///
/// assert_eq!(TabSize::default().get(), 4);
/// assert_eq!(TabSize::try_from(MAX_TAB_SIZE)?.get(), MAX_TAB_SIZE);
/// assert_eq!(TabSize::try_from(0), Err(InvalidTabSize(0)));
/// assert_eq!(TabSize::try_from(MAX_TAB_SIZE + 1), Err(InvalidTabSize(MAX_TAB_SIZE + 1)));
/// # Ok::<(), InvalidTabSize>(())
/// ```
#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
#[serde(try_from = "u32", into = "u32")]
pub struct TabSize(NonZeroU32);

impl TabSize {
    /// The wrapped tab size, within 1 to [`MAX_TAB_SIZE`].
    #[must_use]
    pub const fn get(self) -> u32 {
        self.0.get()
    }
}

impl Default for TabSize {
    fn default() -> Self {
        const DEFAULT: TabSize = match NonZeroU32::new(DEFAULT_TAB_SIZE) {
            Some(size) => TabSize(size),
            None => panic!("the default tab size must be non-zero"),
        };
        DEFAULT
    }
}

impl TryFrom<u32> for TabSize {
    type Error = InvalidTabSize;

    fn try_from(value: u32) -> Result<Self, Self::Error> {
        match NonZeroU32::new(value) {
            Some(size) if value <= MAX_TAB_SIZE => Ok(Self(size)),
            _ => Err(InvalidTabSize(value)),
        }
    }
}

impl From<TabSize> for u32 {
    fn from(size: TabSize) -> Self {
        size.get()
    }
}

impl JsonSchema for TabSize {
    fn schema_name() -> std::borrow::Cow<'static, str> {
        "TabSize".into()
    }

    fn json_schema(_generator: &mut schemars::SchemaGenerator) -> schemars::Schema {
        schemars::json_schema!({
            "type": "integer",
            "minimum": 1,
            "maximum": MAX_TAB_SIZE,
            "default": DEFAULT_TAB_SIZE,
        })
    }
}

/// Why a client-supplied range was rejected.
#[derive(Debug, Clone, Copy, PartialEq, Eq, Error)]
pub enum InvalidRange {
    /// The start position is invalid.
    #[error("invalid range start: {0}")]
    Start(InvalidPosition),
    /// The end position is invalid.
    #[error("invalid range end: {0}")]
    End(InvalidPosition),
    /// The start lies after the end.
    #[error("Start position must be before or equal to end position")]
    Reversed,
    /// The range spans more than [`MAX_RANGE_LINES`] lines.
    #[error("Range size must be <= {MAX_RANGE_LINES} lines")]
    TooManyLines,
}

/// A 1-based MCP position taken as input by `Translator::handle_*` methods.
///
/// Kept distinct from [`Position2D`] (which carries an *output* position back
/// to the caller) and made of two [`NonZeroU32`]s, so a zero position cannot
/// exist and a call site that swaps `line` and `character` still names them
/// (#322). A position typed by a client goes through [`Self::from_client`],
/// the only fallible constructor; positions derived from server output
/// convert infallibly through `Position::from_server_output`.
///
/// # Examples
///
/// ```
/// use mcpls_core::bridge::{InvalidPosition, Position};
///
/// let position = Position::from_client(3, 5)?;
/// assert_eq!((position.line().get(), position.character().get()), (3, 5));
/// assert_eq!(Position::from_client(0, 1), Err(InvalidPosition::ZeroBased));
/// # Ok::<(), InvalidPosition>(())
/// ```
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub struct Position {
    line: NonZeroU32,
    character: NonZeroU32,
}

impl Position {
    /// Builds a position from client-supplied 1-based numbers.
    ///
    /// # Errors
    ///
    /// Returns [`InvalidPosition::ZeroBased`] for a zero line or character
    /// and [`InvalidPosition::TooLarge`] above [`MAX_POSITION_VALUE`].
    pub const fn from_client(line: u32, character: u32) -> Result<Self, InvalidPosition> {
        let (Some(line), Some(character)) = (NonZeroU32::new(line), NonZeroU32::new(character))
        else {
            return Err(InvalidPosition::ZeroBased);
        };
        if line.get() > MAX_POSITION_VALUE || character.get() > MAX_POSITION_VALUE {
            return Err(InvalidPosition::TooLarge);
        }
        Ok(Self { line, character })
    }

    /// Line number (1-based).
    #[must_use]
    pub const fn line(self) -> NonZeroU32 {
        self.line
    }

    /// Character offset (1-based).
    #[must_use]
    pub const fn character(self) -> NonZeroU32 {
        self.character
    }

    /// Zero-based LSP line.
    #[must_use]
    pub const fn lsp_line(self) -> u32 {
        self.line.get().saturating_sub(1)
    }

    /// Zero-based character offset, still in UTF-16 units.
    #[must_use]
    pub const fn lsp_character(self) -> u32 {
        self.character.get().saturating_sub(1)
    }

    /// Reuses a position taken from server output, which is already 1-based
    /// MCP form, as a handler input position. Deliberately not a `From`
    /// impl: a position typed by a client must go through
    /// [`Self::from_client`]. A zero, which converted LSP output never
    /// carries, clamps to 1.
    pub(crate) fn from_server_output(position: &Position2D) -> Self {
        let clamp = |value: u32| NonZeroU32::new(value).unwrap_or(NonZeroU32::MIN);
        Self {
            line: clamp(position.line),
            character: clamp(position.character),
        }
    }

    /// Builds a fixture position, panicking on an invalid one.
    #[cfg(test)]
    pub(crate) fn at(line: u32, character: u32) -> Self {
        Self::from_client(line, character).expect("fixture position is valid")
    }
}

/// An ordered pair of positions, `start <= end`.
///
/// # Examples
///
/// ```
/// use mcpls_core::bridge::{InvalidRange, Position, PositionRange};
///
/// let start = Position::from_client(1, 1).unwrap();
/// let end = Position::from_client(2, 4).unwrap();
/// assert!(PositionRange::new(start, end).is_ok());
/// assert_eq!(PositionRange::new(end, start), Err(InvalidRange::Reversed));
/// ```
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub struct PositionRange {
    start: Position,
    end: Position,
}

impl PositionRange {
    /// Builds an ordered range.
    ///
    /// # Errors
    ///
    /// Returns [`InvalidRange::Reversed`] when `start` lies after `end`.
    pub fn new(start: Position, end: Position) -> Result<Self, InvalidRange> {
        let ordered = (start.line, start.character) <= (end.line, end.character);
        ordered
            .ok_or(InvalidRange::Reversed)
            .map(|()| Self { start, end })
    }

    /// Builds a range from client-supplied 1-based numbers.
    ///
    /// # Errors
    ///
    /// Returns the invalid endpoint or [`InvalidRange::Reversed`].
    pub fn from_client(
        (start_line, start_character): (u32, u32),
        (end_line, end_character): (u32, u32),
    ) -> Result<Self, InvalidRange> {
        let start =
            Position::from_client(start_line, start_character).map_err(InvalidRange::Start)?;
        let end = Position::from_client(end_line, end_character).map_err(InvalidRange::End)?;
        Self::new(start, end)
    }

    /// First position of the range.
    #[must_use]
    pub const fn start(self) -> Position {
        self.start
    }

    /// Last position of the range.
    #[must_use]
    pub const fn end(self) -> Position {
        self.end
    }
}

/// A [`PositionRange`] spanning at most [`MAX_RANGE_LINES`] lines, taken by
/// the tools whose server-side cost grows with the range.
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub struct BoundedRange(PositionRange);

impl BoundedRange {
    /// The underlying ordered range.
    #[must_use]
    pub const fn range(self) -> PositionRange {
        self.0
    }
}

impl TryFrom<PositionRange> for BoundedRange {
    type Error = InvalidRange;

    fn try_from(range: PositionRange) -> Result<Self, Self::Error> {
        let span = range.end.line.get().saturating_sub(range.start.line.get());
        (span <= MAX_RANGE_LINES)
            .ok_or(InvalidRange::TooManyLines)
            .map(|()| Self(range))
    }
}

/// Range in a document (1-based for MCP).
#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize, JsonSchema)]
pub struct Range {
    /// Start position.
    pub start: Position2D,
    /// End position.
    pub end: Position2D,
}

/// Location in a document.
#[derive(Debug, Clone, Serialize, Deserialize, JsonSchema)]
pub struct Location {
    /// URI of the document.
    pub uri: String,
    /// Range within the document.
    pub range: Range,
    /// Whether this location is not provably inside a configured workspace root (stdlib, a dependency).
    ///
    /// Advisory only, not a security/safety guarantee: read-only navigation
    /// results are never filtered by workspace containment (a legitimate
    /// result routinely points into the standard library or a dependency),
    /// so callers that want to apply their own policy toward out-of-workspace
    /// locations can check this flag. The check is purely lexical -- it does
    /// not resolve symlinks. A root counts together with the spellings it
    /// was configured or launched under (for example a symlinked path or the
    /// shell's logical working directory), but a location reached through any
    /// other symlink (e.g. a package manager's symlinked dependency store)
    /// can read `true` even though it is genuinely inside the workspace. Also
    /// always `true` when no workspace roots are configured: without a
    /// configured root, nothing can be vouched for as inside the workspace.
    /// Omitted (defaults to `false`) when serialized.
    #[serde(default, skip_serializing_if = "is_false")]
    pub out_of_workspace: bool,
}

/// `skip_serializing_if` predicate for a `bool` field that should be omitted
/// from the serialized output when `false`.
///
/// Takes `&bool` rather than `bool` because serde's `skip_serializing_if`
/// always calls the predicate with a field reference.
#[expect(
    clippy::trivially_copy_pass_by_ref,
    reason = "serde's `skip_serializing_if` requires `fn(&T) -> bool`"
)]
const fn is_false(value: &bool) -> bool {
    !*value
}

/// How a non-UTF-16 server's `character` offsets became inexact in a result.
// Variant order matters: derived `Ord` makes `Request` > `Response`, so `Option::max` keeps the worse.
#[derive(
    Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Serialize, Deserialize, JsonSchema,
)]
#[serde(rename_all = "snake_case")]
pub enum PositionDegradation {
    /// Only offsets in the returned data may be inexact. The result still
    /// describes the symbol that was asked about; keep it and treat the
    /// returned `character` values as approximate.
    Response,
    /// The queried position was sent to the server unconverted, so the result
    /// may describe a different symbol. Do not trust it.
    Request,
}

/// Result of a hover request.
#[derive(Debug, Clone, Serialize, Deserialize, JsonSchema)]
pub struct HoverResult {
    /// Hover contents as markdown string.
    pub contents: String,
    /// Optional range the hover applies to.
    pub range: Option<Range>,
    /// Set only when some `character` offsets are inexact (non-UTF-16 servers); omitted otherwise.
    ///
    /// Tells whether the queried position or only the returned offsets are affected.
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub positions_degraded: Option<PositionDegradation>,
}

/// A single diagnostic.
#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize, JsonSchema)]
pub struct Diagnostic {
    /// Range where the diagnostic applies.
    pub range: Range,
    /// Severity of the diagnostic.
    pub severity: ReportedSeverity,
    /// Diagnostic message.
    pub message: String,
    /// Optional diagnostic code.
    pub code: Option<String>,
}

/// Result of a diagnostics request.
#[derive(Debug, Clone, Serialize, Deserialize, JsonSchema)]
pub struct DiagnosticsResult {
    /// List of diagnostics for the document.
    pub diagnostics: Vec<Diagnostic>,
    /// Set only when some `character` offsets are inexact (non-UTF-16 servers); omitted otherwise.
    ///
    /// Tells whether the queried position or only the returned offsets are affected.
    #[serde(default, skip_serializing_if = "Option::is_none")]
    #[schemars(with = "PositionDegradation")]
    pub positions_degraded: Option<PositionDegradation>,
}

/// Result of a `get_diagnostics` request: [`DiagnosticsResult`] plus the
/// opt-in enclosing-symbol context.
#[derive(Debug, Clone, Serialize, Deserialize, JsonSchema)]
pub struct DocumentDiagnosticsResult {
    /// List of diagnostics for the document.
    pub diagnostics: Vec<ContextualDiagnostic>,
    /// Set only when some `character` offsets are inexact (non-UTF-16 servers); omitted otherwise.
    ///
    /// Tells whether the queried position or only the returned offsets are affected.
    #[serde(default, skip_serializing_if = "Option::is_none")]
    #[schemars(with = "PositionDegradation")]
    pub positions_degraded: Option<PositionDegradation>,
    /// Set only with `context: "enclosing_symbol"`: how many files were enriched or skipped.
    ///
    /// Set only when that context was requested and the file has diagnostics.
    #[serde(default, skip_serializing_if = "Option::is_none")]
    #[schemars(with = "EnrichmentSummary")]
    pub enrichment: Option<EnrichmentSummary>,
}

/// A text edit operation.
#[derive(Debug, Clone, Serialize, Deserialize, JsonSchema)]
pub struct TextEdit {
    /// Range to replace.
    pub range: Range,
    /// New text.
    pub new_text: String,
}

/// Changes to a document.
#[derive(Debug, Clone, Serialize, Deserialize, JsonSchema)]
pub struct DocumentChanges {
    /// URI of the document.
    pub uri: String,
    /// List of edits to apply.
    pub edits: Vec<TextEdit>,
}

/// Result of a rename request.
#[derive(Debug, Clone, Serialize, Deserialize, JsonSchema)]
pub struct RenameResult {
    /// Changes to apply across documents.
    pub changes: Vec<DocumentChanges>,
    /// Entries withheld from `changes` -- see [`DroppedEdits`]. A non-empty
    /// value means the rename is incomplete even if `changes` is non-empty,
    /// and callers must not treat this result as the full rename otherwise.
    #[serde(default, skip_serializing_if = "DroppedEdits::is_empty")]
    pub dropped: DroppedEdits,
    /// Set only when some `character` offsets are inexact (non-UTF-16 servers); omitted otherwise.
    ///
    /// Tells whether the queried position or only the returned offsets are affected.
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub positions_degraded: Option<PositionDegradation>,
}

/// Counts of `WorkspaceEdit` entries withheld during conversion to MCP DTOs,
/// broken down by reason (#475).
///
/// `convert_workspace_edit` silently discarded such entries with only a
/// `tracing` log line, so a client applying a [`RenameResult`] or
/// `WorkspaceEditDescription` straight to disk could not tell "nothing to
/// rename" apart from "some of the rename was withheld" -- this makes that
/// distinction visible in the result itself.
#[derive(Debug, Clone, Copy, Default, PartialEq, Eq, Serialize, Deserialize, JsonSchema)]
pub struct DroppedEdits {
    /// Entries referencing a URI outside every configured workspace root.
    #[serde(default, skip_serializing_if = "is_zero")]
    pub out_of_workspace: usize,
    /// `CreateFile`/`RenameFile`/`DeleteFile` document changes, which mcpls
    /// does not translate into MCP DTOs.
    #[serde(default, skip_serializing_if = "is_zero")]
    pub unsupported_file_operation: usize,
    /// `SnippetTextEdit` entries, which mcpls does not translate since it
    /// advertises no `snippetEditSupport`.
    #[serde(default, skip_serializing_if = "is_zero")]
    pub unsupported_snippet_edit: usize,
    /// Edits not admitted because the response exceeded
    /// `MAX_NORMALIZED_LOCATIONS` (#487), including whole files skipped once
    /// the budget was spent.
    #[serde(default, skip_serializing_if = "is_zero")]
    pub exceeds_item_cap: usize,
    /// `documentChanges` text-document edits ignored because a non-empty
    /// `changes` map took precedence and did not already name their URI
    /// (#498).
    #[serde(default, skip_serializing_if = "is_zero")]
    pub shadowed_by_changes: usize,
}

impl DroppedEdits {
    /// Whether no entries were withheld.
    #[must_use]
    pub fn is_empty(&self) -> bool {
        *self == Self::default()
    }
}

#[expect(
    clippy::trivially_copy_pass_by_ref,
    reason = "serde's `skip_serializing_if` requires `fn(&T) -> bool`"
)]
const fn is_zero(count: &usize) -> bool {
    *count == 0
}

/// A completion item.
#[derive(Debug, Clone, Serialize, Deserialize, JsonSchema)]
pub struct Completion {
    /// Label of the completion.
    pub label: String,
    /// LSP numeric completion-item kind (e.g. 3 for Function).
    pub kind: Option<u32>,
    /// Detail information.
    pub detail: Option<String>,
    /// Documentation.
    pub documentation: Option<String>,
}

/// Result of a completions request.
#[derive(Debug, Clone, Serialize, Deserialize, JsonSchema)]
pub struct CompletionsResult {
    /// List of completion items.
    pub items: Vec<Completion>,
    /// Set only when some `character` offsets are inexact (non-UTF-16 servers); omitted otherwise.
    ///
    /// Tells whether the queried position or only the returned offsets are affected.
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub positions_degraded: Option<PositionDegradation>,
}

/// A document symbol.
#[derive(Debug, Clone, Serialize, Deserialize, JsonSchema)]
pub struct Symbol {
    /// Name of the symbol.
    pub name: String,
    /// LSP numeric symbol kind (e.g. 12 for Function).
    pub kind: u32,
    /// Range of the symbol.
    pub range: Range,
    /// Selection range (identifier location).
    pub selection_range: Range,
    /// Child symbols.
    #[serde(skip_serializing_if = "Option::is_none")]
    pub children: Option<Vec<Self>>,
}

/// Result of a document symbols request.
#[derive(Debug, Clone, Serialize, Deserialize, JsonSchema)]
pub struct DocumentSymbolsResult {
    /// List of symbols in the document.
    pub symbols: Vec<Symbol>,
    /// Set only when some `character` offsets are inexact (non-UTF-16 servers); omitted otherwise.
    ///
    /// Tells whether the queried position or only the returned offsets are affected.
    #[serde(default, skip_serializing_if = "Option::is_none")]
    #[schemars(with = "PositionDegradation")]
    pub positions_degraded: Option<PositionDegradation>,
}

/// Result of a format document request.
#[derive(Debug, Clone, Serialize, Deserialize, JsonSchema)]
pub struct FormatDocumentResult {
    /// List of edits to format the document.
    pub edits: Vec<TextEdit>,
    /// Set only when some `character` offsets are inexact (non-UTF-16 servers); omitted otherwise.
    ///
    /// Tells whether the queried position or only the returned offsets are affected.
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub positions_degraded: Option<PositionDegradation>,
}

/// A workspace symbol.
#[derive(Debug, Clone, Serialize, Deserialize, JsonSchema)]
pub struct WorkspaceSymbol {
    /// Name of the symbol.
    pub name: String,
    /// LSP numeric symbol kind (e.g. 12 for Function).
    pub kind: u32,
    /// Location of the symbol.
    pub location: Location,
    /// Optional container name (parent scope).
    #[serde(skip_serializing_if = "Option::is_none")]
    pub container_name: Option<String>,
}

/// Result of workspace symbol search.
#[derive(Debug, Clone, Serialize, Deserialize, JsonSchema)]
pub struct WorkspaceSymbolResult {
    /// List of symbols found.
    pub symbols: Vec<WorkspaceSymbol>,
    /// Whether more symbols matched than `symbols` returns.
    ///
    /// Set whenever any are dropped, by the caller's own smaller `limit` or by the server-side
    /// maximum it is clamped to (see `MAX_NORMALIZED_LOCATIONS`, #474); this does not distinguish
    /// which of the two caused it. Omitted (defaults to `false`) when serialized.
    #[serde(default, skip_serializing_if = "is_false")]
    pub truncated: bool,
    /// Set only when some `character` offsets are inexact (non-UTF-16 servers); omitted otherwise.
    ///
    /// Tells whether the queried position or only the returned offsets are affected.
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub positions_degraded: Option<PositionDegradation>,
    /// Set only when the server itself answered with no symbols: what its answer covers.
    ///
    /// Omitted for a non-empty result.
    #[serde(default, skip_serializing_if = "Option::is_none")]
    #[schemars(with = "IndexCoverage")]
    pub index_coverage: Option<IndexCoverage>,
}

/// A single code action.
#[derive(Debug, Clone, Serialize, Deserialize, JsonSchema)]
pub struct CodeAction {
    /// Title of the code action.
    pub title: String,
    /// Kind of code action (quickfix, refactor, etc.).
    #[serde(skip_serializing_if = "Option::is_none")]
    pub kind: Option<String>,
    /// Diagnostics that this action resolves.
    #[serde(skip_serializing_if = "Vec::is_empty", default)]
    pub diagnostics: Vec<Diagnostic>,
    /// Workspace edit to apply.
    #[serde(skip_serializing_if = "Option::is_none")]
    pub edit: Option<WorkspaceEditDescription>,
    /// Command to execute.
    #[serde(skip_serializing_if = "Option::is_none")]
    pub command: Option<CommandDescription>,
    /// Whether this is the preferred action.
    #[serde(default)]
    pub is_preferred: bool,
}

/// Description of a workspace edit.
#[derive(Debug, Clone, Serialize, Deserialize, JsonSchema)]
pub struct WorkspaceEditDescription {
    /// Changes to apply to documents.
    pub changes: Vec<DocumentChanges>,
    /// Entries withheld from `changes` -- see [`DroppedEdits`].
    #[serde(default, skip_serializing_if = "DroppedEdits::is_empty")]
    pub dropped: DroppedEdits,
}

/// Description of a command.
#[derive(Debug, Clone, Serialize, Deserialize, JsonSchema)]
pub struct CommandDescription {
    /// Title of the command.
    pub title: String,
    /// Command identifier.
    pub command: String,
    /// Command arguments.
    #[serde(skip_serializing_if = "Vec::is_empty", default)]
    pub arguments: Vec<serde_json::Value>,
}

/// Result of code actions request.
#[derive(Debug, Clone, Serialize, Deserialize, JsonSchema)]
pub struct CodeActionsResult {
    /// Available code actions.
    pub actions: Vec<CodeAction>,
    /// Whether `actions`, their diagnostics or their edits were capped below the server's response.
    ///
    /// See `MAX_NORMALIZED_LOCATIONS`, #487. A per-action `dropped.exceeds_item_cap` pinpoints
    /// dropped edits. Omitted (defaults to `false`) when serialized.
    #[serde(default, skip_serializing_if = "is_false")]
    pub truncated: bool,
    /// Set only when some `character` offsets are inexact (non-UTF-16 servers); omitted otherwise.
    ///
    /// Tells whether the queried position or only the returned offsets are affected.
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub positions_degraded: Option<PositionDegradation>,
}

/// Result of call hierarchy prepare request.
#[derive(Debug, Clone, Serialize, Deserialize, JsonSchema)]
pub struct CallHierarchyPrepareResult {
    /// List of callable items at the position.
    pub items: Vec<HierarchyItem>,
    /// Whether `items` was capped below the server's full response.
    ///
    /// See `MAX_NORMALIZED_LOCATIONS`, #516. Omitted (defaults to `false`) when serialized.
    #[serde(default, skip_serializing_if = "is_false")]
    pub truncated: bool,
    /// Set only when some `character` offsets are inexact (non-UTF-16 servers); omitted otherwise.
    ///
    /// Tells whether the queried position or only the returned offsets are affected.
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub positions_degraded: Option<PositionDegradation>,
}

/// An incoming call (caller of the current item).
#[derive(Debug, Clone, Serialize, Deserialize, JsonSchema)]
pub struct IncomingCall {
    /// The item that calls the current item.
    pub from: HierarchyItem,
    /// Ranges where the call occurs.
    pub from_ranges: Vec<Range>,
}

/// Result of incoming calls request.
#[derive(Debug, Clone, Serialize, Deserialize, JsonSchema)]
pub struct IncomingCallsResult {
    /// List of incoming calls.
    pub calls: Vec<IncomingCall>,
    /// Whether `calls` (with their `from_ranges`) was capped below the server's full response.
    ///
    /// See `MAX_NORMALIZED_LOCATIONS`, #487. Omitted (defaults to `false`) when serialized.
    #[serde(default, skip_serializing_if = "is_false")]
    pub truncated: bool,
    /// Set only when some `character` offsets are inexact (non-UTF-16 servers); omitted otherwise.
    ///
    /// Tells whether the queried position or only the returned offsets are affected.
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub positions_degraded: Option<PositionDegradation>,
}

/// An outgoing call (callee from the current item).
#[derive(Debug, Clone, Serialize, Deserialize, JsonSchema)]
pub struct OutgoingCall {
    /// The item being called.
    pub to: HierarchyItem,
    /// Ranges where the call occurs.
    pub from_ranges: Vec<Range>,
}

/// Result of outgoing calls request.
#[derive(Debug, Clone, Serialize, Deserialize, JsonSchema)]
pub struct OutgoingCallsResult {
    /// List of outgoing calls.
    pub calls: Vec<OutgoingCall>,
    /// Whether `calls` (with their `from_ranges`) was capped below the server's full response.
    ///
    /// See `MAX_NORMALIZED_LOCATIONS`, #487. Omitted (defaults to `false`) when serialized.
    #[serde(default, skip_serializing_if = "is_false")]
    pub truncated: bool,
    /// Set only when some `character` offsets are inexact (non-UTF-16 servers); omitted otherwise.
    ///
    /// Tells whether the queried position or only the returned offsets are affected.
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub positions_degraded: Option<PositionDegradation>,
}

/// Result of server logs request.
#[derive(Debug, Clone, Serialize, Deserialize, JsonSchema)]
pub struct ServerLogsResult {
    /// List of log entries.
    pub logs: Vec<crate::bridge::notifications::LogEntry>,
}

/// Result of server messages request.
#[derive(Debug, Clone, Serialize, Deserialize, JsonSchema)]
pub struct ServerMessagesResult {
    /// List of server messages.
    pub messages: Vec<crate::bridge::notifications::ServerMessage>,
}

/// A single parameter in a signature.
#[derive(Debug, Clone, Serialize, Deserialize, JsonSchema)]
pub struct SignatureParameter {
    /// Label of the parameter; absent when the server gave an offset pair that does not resolve.
    ///
    /// An offset pair does not resolve when it does not name a substring of the signature label
    /// (out of range, inside a character, or reversed).
    #[serde(skip_serializing_if = "Option::is_none")]
    pub label: Option<String>,
    /// Optional documentation for the parameter.
    #[serde(skip_serializing_if = "Option::is_none")]
    pub documentation: Option<String>,
}

/// A single signature overload.
#[derive(Debug, Clone, Serialize, Deserialize, JsonSchema)]
pub struct SignatureInfo {
    /// Full label of the signature.
    pub label: String,
    /// Optional documentation for the signature.
    #[serde(skip_serializing_if = "Option::is_none")]
    pub documentation: Option<String>,
    /// Parameters of the signature.
    pub parameters: Vec<SignatureParameter>,
}

/// Result of a signature help request.
#[derive(Debug, Clone, Serialize, Deserialize, JsonSchema)]
pub struct SignatureHelpResult {
    /// Available signatures.
    pub signatures: Vec<SignatureInfo>,
    /// Index of the active signature.
    #[serde(skip_serializing_if = "Option::is_none")]
    pub active_signature: Option<u32>,
    /// Index of the active parameter within the active signature.
    #[serde(skip_serializing_if = "Option::is_none")]
    pub active_parameter: Option<u32>,
    /// Set only when some `character` offsets are inexact (non-UTF-16 servers); omitted otherwise.
    ///
    /// Tells whether the queried position or only the returned offsets are affected.
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub positions_degraded: Option<PositionDegradation>,
}

/// Locations answering a definition, references, implementation,
/// type-definition or declaration request.
#[derive(Debug, Clone, Serialize, Deserialize, JsonSchema)]
pub struct LocationsResult {
    /// Locations found.
    pub locations: Vec<ContextualLocation>,
    /// Whether `locations` was capped below the server's full response.
    ///
    /// If `true`, more locations exist than are returned here (see `MAX_NORMALIZED_LOCATIONS`,
    /// #474). Omitted (defaults to `false`) when serialized.
    #[serde(default, skip_serializing_if = "is_false")]
    pub truncated: bool,
    /// Set only when some `character` offsets are inexact (non-UTF-16 servers); omitted otherwise.
    ///
    /// Tells whether the queried position or only the returned offsets are affected.
    #[serde(default, skip_serializing_if = "Option::is_none")]
    #[schemars(with = "PositionDegradation")]
    pub positions_degraded: Option<PositionDegradation>,
    /// Set only with `context: "enclosing_symbol"`: how many files were enriched or skipped.
    ///
    /// Set only when that context was requested and at least one item was looked up. It also says
    /// whether the file cap or time budget cut the lookup short.
    #[serde(default, skip_serializing_if = "Option::is_none")]
    #[schemars(with = "EnrichmentSummary")]
    pub enrichment: Option<EnrichmentSummary>,
}

/// What an empty references or workspace-symbol answer covers.
///
/// A language server that indexes only documents sent with `didOpen` answers an empty list for
/// symbols in files this session never opened, so an empty answer is not proof of absence.
#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize, JsonSchema)]
pub struct IndexCoverage {
    /// Documents currently tracked as synced to the server process; LRU eviction lowers it.
    pub synced_documents: u32,
    /// Set only when the server was restarted or respawned; stays set for the rest of the session.
    #[serde(default, skip_serializing_if = "is_false")]
    pub server_restarted: bool,
}

/// Result of a references request: the locations plus an optional index-coverage note.
///
/// A separate type from [`LocationsResult`] so the note's schema is paid for by one tool only.
#[derive(Debug, Clone, Serialize, Deserialize, JsonSchema)]
pub struct ReferencesResult {
    /// The locations found.
    #[serde(flatten)]
    pub result: LocationsResult,
    /// Set only when `locations` is empty: what the routed server's answer covers.
    ///
    /// Omitted for a non-empty result.
    #[serde(default, skip_serializing_if = "Option::is_none")]
    #[schemars(with = "IndexCoverage")]
    pub index_coverage: Option<IndexCoverage>,
}

/// A single inlay hint entry.
#[derive(Debug, Clone, Serialize, Deserialize, JsonSchema)]
pub struct InlayHintEntry {
    /// Position of the hint (1-based MCP).
    pub position: Position2D,
    /// Label text for the hint.
    pub label: String,
    /// LSP numeric inlay-hint kind (1 = Type, 2 = Parameter, or a
    /// server-defined custom value).
    #[serde(skip_serializing_if = "Option::is_none")]
    pub kind: Option<u32>,
    /// Whether to add a space before the hint.
    #[serde(skip_serializing_if = "Option::is_none")]
    pub padding_left: Option<bool>,
    /// Whether to add a space after the hint.
    #[serde(skip_serializing_if = "Option::is_none")]
    pub padding_right: Option<bool>,
    /// Tooltip text.
    #[serde(skip_serializing_if = "Option::is_none")]
    pub tooltip: Option<String>,
}

/// Result of an inlay hints request.
#[derive(Debug, Clone, Serialize, Deserialize, JsonSchema)]
pub struct InlayHintsResult {
    /// List of inlay hints.
    pub hints: Vec<InlayHintEntry>,
    /// Whether `hints` was capped below the server's full response.
    ///
    /// See `MAX_NORMALIZED_LOCATIONS`, #487. Omitted (defaults to `false`) when serialized.
    #[serde(default, skip_serializing_if = "is_false")]
    pub truncated: bool,
    /// Set only when some `character` offsets are inexact (non-UTF-16 servers); omitted otherwise.
    ///
    /// Tells whether the queried position or only the returned offsets are affected.
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub positions_degraded: Option<PositionDegradation>,
}

/// A call or type hierarchy item.
///
/// Returned by the hierarchy tools and accepted back as the typed `item`
/// input of the walking tools (`get_incoming_calls`, `get_outgoing_calls`,
/// `get_supertypes`, `get_subtypes`). LSP's call and type hierarchy items carry the same fields, so one shape
/// serves both. `data` is opaque to the caller and meaningful only to the
/// server that produced the item.
///
/// Lines and columns above [`MAX_POSITION_VALUE`] cannot be passed back, so
/// an item from a `prepare_*` tool whose range crosses that column (for
/// example on a minified line) is rejected by the walking tools.
///
/// # Examples
///
/// ```
/// use mcpls_core::bridge::HierarchyItem;
///
/// let item: HierarchyItem = serde_json::from_value(serde_json::json!({
///     "name": "Base", "kind": 5, "uri": "file:///a.cpp",
///     "range": {"start": {"line": 1, "character": 1}, "end": {"line": 2, "character": 1}},
///     "selectionRange": {"start": {"line": 1, "character": 7}, "end": {"line": 1, "character": 11}},
/// }))
/// .unwrap();
/// assert_eq!(item.name, "Base");
/// assert!(serde_json::from_value::<HierarchyItem>(serde_json::json!({})).is_err());
/// ```
#[derive(Debug, Clone, Serialize, Deserialize, JsonSchema)]
pub struct HierarchyItem {
    /// Name of the symbol.
    pub name: String,
    /// LSP numeric symbol kind (e.g. 12 for Function, 5 for Class).
    pub kind: u32,
    /// More detail for this item.
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub detail: Option<String>,
    /// URI of the document.
    pub uri: String,
    /// Range of the symbol.
    pub range: Range,
    /// Selection range (identifier location).
    ///
    /// Serialized as `selectionRange` (camelCase) so that a returned item
    /// round-trips when the MCP client passes it back to a walking tool.
    #[serde(rename = "selectionRange")]
    pub selection_range: Range,
    /// Opaque data to pass back unchanged.
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub data: Option<serde_json::Value>,
    /// Whether this item is not provably inside any configured workspace
    /// root -- see [`Location::out_of_workspace`] for the exact semantics
    /// and caveats (advisory only, lexical, symlink-unaware). Ignored on
    /// input.
    #[serde(default, skip_serializing_if = "is_false")]
    pub out_of_workspace: bool,
}

/// Why a client-supplied [`HierarchyItem`] was rejected.
#[derive(Debug, Clone, Copy, PartialEq, Eq, Error)]
pub enum InvalidHierarchyItem {
    /// The item's `range` is invalid.
    #[error("invalid hierarchy item range: {0}")]
    Range(InvalidRange),
    /// The item's `selectionRange` is invalid.
    #[error("invalid hierarchy item selectionRange: {0}")]
    SelectionRange(InvalidRange),
}

/// A [`HierarchyItem`] whose ranges passed client-input validation.
///
/// Taken by the walking handlers instead of the raw wire DTO, so a zero,
/// oversized or reversed range cannot reach the LSP conversion. Built only by
/// [`Self::from_client`].
///
/// # Examples
///
/// ```
/// use std::assert_matches;
///
/// use mcpls_core::bridge::{CheckedHierarchyItem, HierarchyItem, InvalidHierarchyItem};
///
/// let wire = |line: u32| -> HierarchyItem {
///     serde_json::from_value(serde_json::json!({
///         "name": "Base", "kind": 5, "uri": "file:///a.cpp",
///         "range": {"start": {"line": line, "character": 1}, "end": {"line": 2, "character": 1}},
///         "selectionRange": {"start": {"line": 1, "character": 7}, "end": {"line": 1, "character": 11}},
///     }))
///     .unwrap()
/// };
/// assert!(CheckedHierarchyItem::from_client(wire(1)).is_ok());
/// assert_matches!(
///     CheckedHierarchyItem::from_client(wire(0)),
///     Err(InvalidHierarchyItem::Range(_))
/// );
/// ```
#[derive(Debug, Clone)]
pub struct CheckedHierarchyItem {
    pub(super) name: String,
    pub(super) kind: u32,
    pub(super) detail: Option<String>,
    pub(super) uri: String,
    pub(super) range: PositionRange,
    pub(super) selection_range: PositionRange,
    pub(super) data: Option<serde_json::Value>,
}

impl CheckedHierarchyItem {
    /// Validates the ranges of a client-supplied item.
    ///
    /// # Errors
    ///
    /// Returns which range was zero-based, above [`MAX_POSITION_VALUE`] or
    /// reversed. Containment of `selectionRange` in `range` is not checked.
    pub fn from_client(item: HierarchyItem) -> Result<Self, InvalidHierarchyItem> {
        let range = checked_range(&item.range).map_err(InvalidHierarchyItem::Range)?;
        let selection_range =
            checked_range(&item.selection_range).map_err(InvalidHierarchyItem::SelectionRange)?;
        Ok(Self {
            name: item.name,
            kind: item.kind,
            detail: item.detail,
            uri: item.uri,
            range,
            selection_range,
            data: item.data,
        })
    }

    /// The item's document URI, as the client sent it.
    #[must_use]
    pub fn uri(&self) -> &str {
        &self.uri
    }
}

fn checked_range(range: &Range) -> Result<PositionRange, InvalidRange> {
    PositionRange::from_client(
        (range.start.line, range.start.character),
        (range.end.line, range.end.character),
    )
}

/// Result of a type hierarchy prepare, supertypes or subtypes request.
#[derive(Debug, Clone, Serialize, Deserialize, JsonSchema)]
pub struct TypeHierarchyResult {
    /// Type hierarchy items at the position, or the supertypes/subtypes of
    /// the queried item.
    pub items: Vec<HierarchyItem>,
    /// Whether `items` was capped below the server's full response.
    ///
    /// See `MAX_NORMALIZED_LOCATIONS`. Omitted (defaults to `false`) when serialized.
    #[serde(default, skip_serializing_if = "is_false")]
    pub truncated: bool,
    /// Set only when some `character` offsets are inexact (non-UTF-16 servers); omitted otherwise.
    ///
    /// Tells whether the queried position or only the returned offsets are affected.
    #[serde(default, skip_serializing_if = "Option::is_none")]
    #[schemars(with = "PositionDegradation")]
    pub positions_degraded: Option<PositionDegradation>,
}

/// Whether the symbol at a position can be renamed, as answered by
/// `textDocument/prepareRename`.
///
/// # Examples
///
/// ```
/// use mcpls_core::bridge::PrepareRenameOutcome;
///
/// let outcome = PrepareRenameOutcome::NotRenameable { server_message: None };
/// assert_eq!(
///     serde_json::to_value(&outcome).unwrap(),
///     serde_json::json!({"status": "not_renameable"})
/// );
/// ```
#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize, JsonSchema)]
#[serde(tag = "status", rename_all = "snake_case")]
pub enum PrepareRenameOutcome {
    /// The identifier can be renamed.
    Renameable {
        /// Range of the identifier that a rename would replace.
        range: Range,
        /// Current name of the identifier, when the server supplies it.
        #[serde(default, skip_serializing_if = "Option::is_none")]
        placeholder: Option<String>,
    },
    /// The server accepts a rename here but leaves the identifier range to the client.
    ///
    /// The client applies its own word-selection rule; no range is invented.
    DefaultBehavior,
    /// The position cannot be renamed. Distinct from a transport failure and
    /// from a server that does not support rename preparation.
    NotRenameable {
        /// The server's own explanation, when it reported one as an error.
        #[serde(default, skip_serializing_if = "Option::is_none")]
        server_message: Option<String>,
    },
}

/// Result of a prepare rename request.
#[derive(Debug, Clone, Serialize, Deserialize, JsonSchema)]
pub struct PrepareRenameResult {
    /// The rename-preparation verdict.
    #[serde(flatten)]
    pub outcome: PrepareRenameOutcome,
    /// Set only when some `character` offsets are inexact (non-UTF-16 servers); omitted otherwise.
    ///
    /// Tells whether the queried position or only the returned offsets are affected.
    #[serde(default, skip_serializing_if = "Option::is_none")]
    #[schemars(with = "PositionDegradation")]
    pub positions_degraded: Option<PositionDegradation>,
}

/// How a document highlight occurrence uses its symbol.
#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize, JsonSchema)]
#[serde(rename_all = "snake_case")]
pub enum DocumentHighlightKind {
    /// A textual occurrence; also what a server that omits the kind means.
    Text,
    /// A read access, such as reading a variable.
    Read,
    /// A write access, such as assigning a variable.
    Write,
}

/// One occurrence of a symbol within a document.
#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize, JsonSchema)]
pub struct DocumentHighlightEntry {
    /// Range of the occurrence.
    pub range: Range,
    /// How the occurrence uses the symbol.
    pub kind: DocumentHighlightKind,
}

/// Most ranges one selection chain returns; a longer chain is cut to its
/// innermost ranges.
pub const MAX_SELECTION_CHAIN: usize = 32;

/// Result of a selection range request: the ranges enclosing a position.
///
/// # Examples
///
/// ```
/// use mcpls_core::bridge::{MAX_SELECTION_CHAIN, SelectionRangesResult};
///
/// let result: SelectionRangesResult = serde_json::from_value(serde_json::json!({
///     "ranges": [],
/// }))?;
/// assert!(result.ranges.is_empty() && !result.truncated);
/// assert_eq!(MAX_SELECTION_CHAIN, 32);
/// # Ok::<(), serde_json::Error>(())
/// ```
#[derive(Debug, Clone, Serialize, Deserialize, JsonSchema)]
pub struct SelectionRangesResult {
    /// Ranges enclosing the position, innermost first, as the server reported them.
    ///
    /// They are not merged, reordered or added to.
    pub ranges: Vec<Range>,
    /// Whether the chain was longer than `MAX_SELECTION_CHAIN` and the
    /// outermost ranges were dropped. Omitted when `false`.
    #[serde(default, skip_serializing_if = "is_false")]
    pub truncated: bool,
    /// Set only when the queried position or some `character` offsets are inexact (non-UTF-16).
    #[serde(default, skip_serializing_if = "Option::is_none")]
    #[schemars(with = "PositionDegradation")]
    pub positions_degraded: Option<PositionDegradation>,
}

/// Largest `collapsed_text` returned for a folding region, in bytes before the
/// truncation marker.
pub const MAX_COLLAPSED_TEXT_BYTES: usize = 256;

/// What a folding region covers, from the LSP's open-string kind.
#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
#[serde(rename_all = "snake_case")]
pub enum FoldingKind {
    /// A comment block.
    Comment,
    /// An import group.
    Imports,
    /// A marked region.
    Region,
    /// No kind, or a server-defined one.
    Unspecified,
}

/// Which folding regions to return.
///
/// `Unspecified` regions are returned only by [`Self::All`]. Accepted in any
/// case, like every other kind filter.
#[derive(Debug, Clone, Copy, Default, PartialEq, Eq)]
pub enum FoldingKindFilter {
    /// Every region.
    #[default]
    All,
    /// Comment blocks only.
    Comment,
    /// Import groups only.
    Imports,
    /// Marked regions only.
    Region,
}

/// Schema of the closed string sets, compact on the wire.
impl JsonSchema for FoldingKind {
    fn schema_name() -> std::borrow::Cow<'static, str> {
        "FoldingKind".into()
    }

    fn json_schema(_generator: &mut schemars::SchemaGenerator) -> schemars::Schema {
        schemars::json_schema!({
            "type": "string",
            "enum": ["comment", "imports", "region", "unspecified"],
        })
    }
}

impl JsonSchema for FoldingKindFilter {
    fn schema_name() -> std::borrow::Cow<'static, str> {
        Self::SCHEMA_NAME.into()
    }

    fn json_schema(_generator: &mut schemars::SchemaGenerator) -> schemars::Schema {
        Self::schema()
    }
}

kind_filter::closed_kind_filter!(FoldingKindFilter, "FoldingKindFilter");

impl FoldingKindFilter {
    /// Every filter, in documentation order.
    pub const ALL: [Self; 4] = [Self::All, Self::Comment, Self::Imports, Self::Region];

    /// The lowercase spelling the schema documents.
    #[must_use]
    pub const fn as_str(self) -> &'static str {
        match self {
            Self::All => "all",
            Self::Comment => "comment",
            Self::Imports => "imports",
            Self::Region => "region",
        }
    }

    /// Whether a region of `kind` passes this filter.
    ///
    /// # Examples
    ///
    /// ```
    /// use mcpls_core::bridge::{FoldingKind, FoldingKindFilter};
    ///
    /// assert!(FoldingKindFilter::All.admits(FoldingKind::Unspecified));
    /// assert!(FoldingKindFilter::Imports.admits(FoldingKind::Imports));
    /// assert!(!FoldingKindFilter::Imports.admits(FoldingKind::Unspecified));
    /// ```
    #[must_use]
    pub const fn admits(self, kind: FoldingKind) -> bool {
        matches!(
            (self, kind),
            (Self::All, _)
                | (Self::Comment, FoldingKind::Comment)
                | (Self::Imports, FoldingKind::Imports)
                | (Self::Region, FoldingKind::Region)
        )
    }
}

/// One foldable region of a file, 1-based.
#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize, JsonSchema)]
pub struct FoldingRegion {
    /// First line.
    pub start_line: u32,
    /// Last line.
    pub end_line: u32,
    /// Where the fold starts, when the server says; absent means line end.
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub start_character: Option<u32>,
    /// Where the fold ends, when the server says; absent means line end.
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub end_character: Option<u32>,
    /// Region kind.
    pub kind: FoldingKind,
    /// Text shown in place of the fold, when the server gives it.
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub collapsed_text: Option<String>,
}

/// Result of a folding range request.
#[derive(Debug, Clone, Serialize, Deserialize, JsonSchema)]
pub struct FoldingRangesResult {
    /// The regions, by ascending start line then descending end line.
    pub regions: Vec<FoldingRegion>,
    /// Whether more matching regions exist than are returned. Omitted when
    /// `false`.
    #[serde(default, skip_serializing_if = "is_false")]
    pub truncated: bool,
    /// Set only when some `character` offsets are inexact (non-UTF-16 servers); omitted otherwise.
    #[serde(default, skip_serializing_if = "Option::is_none")]
    #[schemars(with = "PositionDegradation")]
    pub positions_degraded: Option<PositionDegradation>,
}

/// Result of a document highlights request.
#[derive(Debug, Clone, Serialize, Deserialize, JsonSchema)]
pub struct DocumentHighlightsResult {
    /// Occurrences of the symbol at the position within the file.
    pub highlights: Vec<DocumentHighlightEntry>,
    /// Whether `highlights` was capped below the server's full response.
    ///
    /// See `MAX_NORMALIZED_LOCATIONS`. Omitted (defaults to `false`) when serialized.
    #[serde(default, skip_serializing_if = "is_false")]
    pub truncated: bool,
    /// Set only when some `character` offsets are inexact (non-UTF-16 servers); omitted otherwise.
    ///
    /// Tells whether the queried position or only the returned offsets are affected.
    #[serde(default, skip_serializing_if = "Option::is_none")]
    #[schemars(with = "PositionDegradation")]
    pub positions_degraded: Option<PositionDegradation>,
}

impl ServerText for Location {
    fn redact_server_text(&mut self, redactions: &Redactions) {
        let Self {
            uri,
            range: _,
            out_of_workspace: _,
        } = self;
        redactions.note_payload(uri);
    }
}

impl ServerText for HoverResult {
    fn redact_server_text(&mut self, redactions: &Redactions) {
        let Self {
            contents,
            range: _,
            positions_degraded: _,
        } = self;
        redactions.redact_in_place(contents);
    }
}

impl ServerText for LocationsResult {
    fn redact_server_text(&mut self, redactions: &Redactions) {
        let Self {
            locations,
            truncated: _,
            positions_degraded: _,
            enrichment: _,
        } = self;
        locations.redact_server_text(redactions);
    }
}

impl ServerText for ReferencesResult {
    fn redact_server_text(&mut self, redactions: &Redactions) {
        let Self {
            result,
            index_coverage: _,
        } = self;
        result.redact_server_text(redactions);
    }
}

impl ServerText for Diagnostic {
    fn redact_server_text(&mut self, redactions: &Redactions) {
        let Self {
            range: _,
            severity: _,
            message,
            code,
        } = self;
        redactions.redact_in_place(message);
        if let Some(code) = code {
            redactions.redact_in_place(code);
        }
    }
}

// Document diagnostics are redacted where they enter the cache or the pull path.
impl ServerText for DiagnosticsResult {
    fn redact_server_text(&mut self, _redactions: &Redactions) {
        let Self {
            diagnostics: _,
            positions_degraded: _,
        } = self;
    }
}

impl ServerText for DocumentDiagnosticsResult {
    fn redact_server_text(&mut self, _redactions: &Redactions) {
        let Self {
            diagnostics: _,
            positions_degraded: _,
            enrichment: _,
        } = self;
    }
}

impl ServerText for TextEdit {
    fn redact_server_text(&mut self, redactions: &Redactions) {
        let Self { range: _, new_text } = self;
        redactions.note_payload(new_text);
    }
}

impl ServerText for DocumentChanges {
    fn redact_server_text(&mut self, redactions: &Redactions) {
        let Self { uri, edits } = self;
        redactions.note_payload(uri);
        edits.redact_server_text(redactions);
    }
}

impl ServerText for RenameResult {
    fn redact_server_text(&mut self, redactions: &Redactions) {
        let Self {
            changes,
            dropped: _,
            positions_degraded: _,
        } = self;
        changes.redact_server_text(redactions);
    }
}

impl ServerText for Completion {
    fn redact_server_text(&mut self, redactions: &Redactions) {
        let Self {
            label,
            kind: _,
            detail,
            documentation,
        } = self;
        redactions.note_payload(label);
        for prose in [detail, documentation].into_iter().flatten() {
            redactions.redact_in_place(prose);
        }
    }
}

impl ServerText for CompletionsResult {
    fn redact_server_text(&mut self, redactions: &Redactions) {
        let Self {
            items,
            positions_degraded: _,
        } = self;
        items.redact_server_text(redactions);
    }
}

impl ServerText for Symbol {
    fn redact_server_text(&mut self, redactions: &Redactions) {
        let Self {
            name,
            kind: _,
            range: _,
            selection_range: _,
            children,
        } = self;
        redactions.note_payload(name);
        if let Some(children) = children {
            children.redact_server_text(redactions);
        }
    }
}

impl ServerText for DocumentSymbolsResult {
    fn redact_server_text(&mut self, redactions: &Redactions) {
        let Self {
            symbols,
            positions_degraded: _,
        } = self;
        symbols.redact_server_text(redactions);
    }
}

impl ServerText for FormatDocumentResult {
    fn redact_server_text(&mut self, redactions: &Redactions) {
        let Self {
            edits,
            positions_degraded: _,
        } = self;
        edits.redact_server_text(redactions);
    }
}

impl ServerText for WorkspaceSymbol {
    fn redact_server_text(&mut self, redactions: &Redactions) {
        let Self {
            name,
            kind: _,
            location,
            container_name,
        } = self;
        redactions.note_payload(name);
        if let Some(container) = container_name {
            redactions.note_payload(container);
        }
        location.redact_server_text(redactions);
    }
}

impl ServerText for WorkspaceSymbolResult {
    fn redact_server_text(&mut self, redactions: &Redactions) {
        let Self {
            symbols,
            truncated: _,
            positions_degraded: _,
            index_coverage: _,
        } = self;
        symbols.redact_server_text(redactions);
    }
}

impl ServerText for CodeAction {
    fn redact_server_text(&mut self, redactions: &Redactions) {
        let Self {
            title,
            kind: _,
            diagnostics,
            edit,
            command,
            is_preferred: _,
        } = self;
        redactions.redact_in_place(title);
        diagnostics.redact_server_text(redactions);
        edit.redact_server_text(redactions);
        command.redact_server_text(redactions);
    }
}

impl ServerText for WorkspaceEditDescription {
    fn redact_server_text(&mut self, redactions: &Redactions) {
        let Self {
            changes,
            dropped: _,
        } = self;
        changes.redact_server_text(redactions);
    }
}

impl ServerText for CommandDescription {
    fn redact_server_text(&mut self, redactions: &Redactions) {
        let Self {
            title,
            command,
            arguments,
        } = self;
        redactions.redact_in_place(title);
        redactions.note_payload(command);
        for argument in arguments {
            redactions.note_payload_json(argument);
        }
    }
}

impl ServerText for CodeActionsResult {
    fn redact_server_text(&mut self, redactions: &Redactions) {
        let Self {
            actions,
            truncated: _,
            positions_degraded: _,
        } = self;
        actions.redact_server_text(redactions);
    }
}

impl ServerText for CallHierarchyPrepareResult {
    fn redact_server_text(&mut self, redactions: &Redactions) {
        let Self {
            items,
            truncated: _,
            positions_degraded: _,
        } = self;
        items.redact_server_text(redactions);
    }
}

impl ServerText for IncomingCall {
    fn redact_server_text(&mut self, redactions: &Redactions) {
        let Self {
            from,
            from_ranges: _,
        } = self;
        from.redact_server_text(redactions);
    }
}

impl ServerText for IncomingCallsResult {
    fn redact_server_text(&mut self, redactions: &Redactions) {
        let Self {
            calls,
            truncated: _,
            positions_degraded: _,
        } = self;
        calls.redact_server_text(redactions);
    }
}

impl ServerText for OutgoingCall {
    fn redact_server_text(&mut self, redactions: &Redactions) {
        let Self { to, from_ranges: _ } = self;
        to.redact_server_text(redactions);
    }
}

impl ServerText for OutgoingCallsResult {
    fn redact_server_text(&mut self, redactions: &Redactions) {
        let Self {
            calls,
            truncated: _,
            positions_degraded: _,
        } = self;
        calls.redact_server_text(redactions);
    }
}

// Logs and messages are redacted when the notification enters the cache.
impl ServerText for ServerLogsResult {
    fn redact_server_text(&mut self, _redactions: &Redactions) {
        let Self { logs: _ } = self;
    }
}

impl ServerText for ServerMessagesResult {
    fn redact_server_text(&mut self, _redactions: &Redactions) {
        let Self { messages: _ } = self;
    }
}

impl ServerText for SignatureParameter {
    fn redact_server_text(&mut self, redactions: &Redactions) {
        let Self {
            label,
            documentation,
        } = self;
        for prose in [label, documentation].into_iter().flatten() {
            redactions.redact_in_place(prose);
        }
    }
}

impl ServerText for SignatureInfo {
    fn redact_server_text(&mut self, redactions: &Redactions) {
        let Self {
            label,
            documentation,
            parameters,
        } = self;
        redactions.redact_in_place(label);
        if let Some(documentation) = documentation {
            redactions.redact_in_place(documentation);
        }
        parameters.redact_server_text(redactions);
    }
}

impl ServerText for SignatureHelpResult {
    fn redact_server_text(&mut self, redactions: &Redactions) {
        let Self {
            signatures,
            active_signature: _,
            active_parameter: _,
            positions_degraded: _,
        } = self;
        signatures.redact_server_text(redactions);
    }
}

impl ServerText for InlayHintEntry {
    fn redact_server_text(&mut self, redactions: &Redactions) {
        let Self {
            position: _,
            label,
            kind: _,
            padding_left: _,
            padding_right: _,
            tooltip,
        } = self;
        redactions.redact_in_place(label);
        if let Some(tooltip) = tooltip {
            redactions.redact_in_place(tooltip);
        }
    }
}

impl ServerText for InlayHintsResult {
    fn redact_server_text(&mut self, redactions: &Redactions) {
        let Self {
            hints,
            truncated: _,
            positions_degraded: _,
        } = self;
        hints.redact_server_text(redactions);
    }
}

impl ServerText for HierarchyItem {
    fn redact_server_text(&mut self, redactions: &Redactions) {
        let Self {
            name,
            kind: _,
            detail,
            uri,
            range: _,
            selection_range: _,
            data,
            out_of_workspace: _,
        } = self;
        redactions.note_payload(name);
        if let Some(detail) = detail {
            redactions.note_payload(detail);
        }
        redactions.note_payload(uri);
        if let Some(data) = data {
            redactions.note_payload_json(data);
        }
    }
}

impl ServerText for TypeHierarchyResult {
    fn redact_server_text(&mut self, redactions: &Redactions) {
        let Self {
            items,
            truncated: _,
            positions_degraded: _,
        } = self;
        items.redact_server_text(redactions);
    }
}

impl ServerText for PrepareRenameOutcome {
    fn redact_server_text(&mut self, redactions: &Redactions) {
        match self {
            Self::Renameable {
                range: _,
                placeholder,
            } => {
                if let Some(placeholder) = placeholder {
                    redactions.note_payload(placeholder);
                }
            }
            Self::DefaultBehavior => {}
            Self::NotRenameable { server_message } => {
                if let Some(message) = server_message {
                    redactions.redact_in_place(message);
                }
            }
        }
    }
}

impl ServerText for PrepareRenameResult {
    fn redact_server_text(&mut self, redactions: &Redactions) {
        let Self {
            outcome,
            positions_degraded: _,
        } = self;
        outcome.redact_server_text(redactions);
    }
}

impl ServerText for DocumentHighlightsResult {
    fn redact_server_text(&mut self, _redactions: &Redactions) {
        let Self {
            highlights: _,
            truncated: _,
            positions_degraded: _,
        } = self;
    }
}

impl ServerText for FoldingRangesResult {
    fn redact_server_text(&mut self, redactions: &Redactions) {
        let Self {
            regions,
            truncated: _,
            positions_degraded: _,
        } = self;
        for region in regions {
            if let Some(text) = &mut region.collapsed_text {
                redactions.redact_in_place(text);
                *text =
                    crate::util::truncate_string(std::mem::take(text), MAX_COLLAPSED_TEXT_BYTES);
            }
        }
    }
}

impl ServerText for SelectionRangesResult {
    fn redact_server_text(&mut self, _redactions: &Redactions) {
        let Self {
            ranges: _,
            truncated: _,
            positions_degraded: _,
        } = self;
    }
}

#[cfg(test)]
mod tests {
    use std::assert_matches;

    fn hierarchy_wire(range: [u32; 4], selection: [u32; 4]) -> HierarchyItem {
        let at = |line, character| serde_json::json!({"line": line, "character": character});
        serde_json::from_value(serde_json::json!({
            "name": "x", "kind": 5, "uri": "file:///a.rs",
            "range": {"start": at(range[0], range[1]), "end": at(range[2], range[3])},
            "selectionRange": {"start": at(selection[0], selection[1]), "end": at(selection[2], selection[3])},
        }))
        .unwrap()
    }

    #[test]
    fn checked_hierarchy_item_accepts_valid_ranges() {
        let item = CheckedHierarchyItem::from_client(hierarchy_wire([1, 1, 2, 1], [1, 7, 1, 9]));
        assert_eq!(item.unwrap().uri(), "file:///a.rs");
    }

    #[test]
    fn checked_hierarchy_item_rejects_bad_range_and_names_it() {
        for bad in [
            [0, 1, 1, 1],
            [1, 0, 1, 1],
            [1, 1, 1, 1_000_001],
            [1, 1, u32::MAX, 1],
            [2, 1, 1, 1],
        ] {
            let err =
                CheckedHierarchyItem::from_client(hierarchy_wire(bad, [1, 1, 1, 1])).unwrap_err();
            assert_matches!(err, InvalidHierarchyItem::Range(_), "{bad:?}");
            let err =
                CheckedHierarchyItem::from_client(hierarchy_wire([1, 1, 9, 1], bad)).unwrap_err();
            assert_matches!(err, InvalidHierarchyItem::SelectionRange(_), "{bad:?}");
        }
    }

    #[test]
    fn checked_hierarchy_item_rejects_selection_column_above_max() {
        let err = CheckedHierarchyItem::from_client(hierarchy_wire(
            [1, 1, 2, 1],
            [1, 1_000_001, 1, 1_000_001],
        ))
        .unwrap_err();
        assert_eq!(
            err,
            InvalidHierarchyItem::SelectionRange(InvalidRange::Start(InvalidPosition::TooLarge))
        );
    }

    use super::*;

    #[test]
    fn test_text_fields_report_the_field_and_the_rule() {
        let blank = NewName::new("  ").unwrap_err();
        assert_eq!(blank.to_string(), "`new_name` cannot be empty");

        let long = NewName::new("x".repeat(MAX_NEW_NAME_LENGTH + 1)).unwrap_err();
        assert_eq!(
            long.reason,
            InvalidBoundedText::TooLong {
                len: MAX_NEW_NAME_LENGTH + 1,
                max: MAX_NEW_NAME_LENGTH,
            }
        );
        assert_eq!(
            NewName::new(" keeps spaces ").unwrap().as_str(),
            " keeps spaces "
        );

        let empty = CompletionTrigger::new("").unwrap_err();
        assert_eq!(empty.field, TextField::Trigger);
        assert_eq!(empty.reason, InvalidBoundedText::Blank);
        assert_eq!(CompletionTrigger::new(" ").unwrap().as_str(), " ");
        assert!(CompletionTrigger::new("x".repeat(MAX_TRIGGER_CHARACTER_BYTES)).is_ok());
        assert_eq!(
            CompletionTrigger::new("x".repeat(MAX_TRIGGER_CHARACTER_BYTES + 1))
                .unwrap_err()
                .reason,
            InvalidBoundedText::TooLong {
                len: MAX_TRIGGER_CHARACTER_BYTES + 1,
                max: MAX_TRIGGER_CHARACTER_BYTES,
            }
        );
    }

    const SECRET: &str = "SuperSecretValue123";

    fn range() -> Range {
        Range {
            start: Position2D {
                line: 1,
                character: 1,
            },
            end: Position2D {
                line: 1,
                character: 2,
            },
        }
    }

    #[test]
    fn test_server_text_redacts_prose_and_leaves_edit_payload() {
        let set = Redactions::new([("API_TOKEN".to_owned(), SECRET.to_owned())]);
        let mut actions = vec![CodeAction {
            title: format!("fix {SECRET}"),
            kind: None,
            diagnostics: vec![Diagnostic {
                range: range(),
                severity: ReportedSeverity::Error,
                message: format!("bad {SECRET}"),
                code: Some(format!("E-{SECRET}")),
            }],
            edit: Some(WorkspaceEditDescription {
                changes: vec![DocumentChanges {
                    uri: format!("file:///{SECRET}.rs"),
                    edits: vec![TextEdit {
                        range: range(),
                        new_text: format!("let k = \"{SECRET}\";"),
                    }],
                }],
                dropped: DroppedEdits::default(),
            }),
            command: None,
            is_preferred: false,
        }];

        actions.redact_server_text(&set);

        let action = &actions[0];
        assert_eq!(action.title, "fix [redacted:API_TOKEN]");
        assert_eq!(action.diagnostics[0].message, "bad [redacted:API_TOKEN]");
        assert_eq!(
            action.diagnostics[0].code.as_deref(),
            Some("E-[redacted:API_TOKEN]")
        );
        let changes = &action.edit.as_ref().unwrap().changes[0];
        assert!(changes.uri.contains(SECRET));
        assert!(changes.edits[0].new_text.contains(SECRET));
    }

    #[test]
    fn test_server_text_completion_keeps_label_and_redacts_detail_and_documentation() {
        let set = Redactions::new([("API_TOKEN".to_owned(), SECRET.to_owned())]);
        let mut completion = Completion {
            label: format!("use_{SECRET}"),
            kind: Some(3),
            detail: Some(format!("fn {SECRET}()")),
            documentation: Some(format!("docs {SECRET}")),
        };

        completion.redact_server_text(&set);

        assert_eq!(completion.label, format!("use_{SECRET}"));
        assert_eq!(
            completion.detail.as_deref(),
            Some("fn [redacted:API_TOKEN]()")
        );
        assert_eq!(
            completion.documentation.as_deref(),
            Some("docs [redacted:API_TOKEN]")
        );
    }

    #[test]
    fn test_server_text_redacts_signature_label_documentation_and_parameters() {
        let set = Redactions::new([("API_TOKEN".to_owned(), SECRET.to_owned())]);
        let mut result = SignatureHelpResult {
            signatures: vec![SignatureInfo {
                label: format!("f({SECRET})"),
                documentation: Some(format!("doc {SECRET}")),
                parameters: vec![SignatureParameter {
                    label: Some(format!("p {SECRET}")),
                    documentation: Some(format!("pd {SECRET}")),
                }],
            }],
            active_signature: Some(0),
            active_parameter: Some(0),
            positions_degraded: None,
        };

        result.redact_server_text(&set);

        let json = serde_json::to_string(&result).unwrap();
        assert!(!json.contains(SECRET), "{json}");
        assert_eq!(json.matches("[redacted:API_TOKEN]").count(), 4, "{json}");
    }

    #[test]
    fn test_server_text_redacts_inlay_label_and_tooltip() {
        let set = Redactions::new([("API_TOKEN".to_owned(), SECRET.to_owned())]);
        let mut hint = InlayHintEntry {
            position: Position2D {
                line: 1,
                character: 1,
            },
            label: format!(": {SECRET}"),
            kind: None,
            padding_left: None,
            padding_right: None,
            tooltip: Some(format!("tip {SECRET}")),
        };

        hint.redact_server_text(&set);

        assert_eq!(hint.label, ": [redacted:API_TOKEN]");
        assert_eq!(hint.tooltip.as_deref(), Some("tip [redacted:API_TOKEN]"));
    }

    #[test]
    fn test_server_text_command_redacts_title_and_keeps_command_and_arguments() {
        let set = Redactions::new([("API_TOKEN".to_owned(), SECRET.to_owned())]);
        let mut command = CommandDescription {
            title: format!("run {SECRET}"),
            command: format!("cmd.{SECRET}"),
            arguments: vec![serde_json::json!({ "key": SECRET })],
        };

        command.redact_server_text(&set);

        assert_eq!(command.title, "run [redacted:API_TOKEN]");
        assert_eq!(command.command, format!("cmd.{SECRET}"));
        assert_eq!(
            command.arguments,
            vec![serde_json::json!({ "key": SECRET })]
        );
    }

    #[test]
    fn test_server_text_leaves_symbol_and_hierarchy_identifiers() {
        let set = Redactions::new([("API_TOKEN".to_owned(), SECRET.to_owned())]);
        let mut symbols = DocumentSymbolsResult {
            symbols: vec![Symbol {
                name: format!("sym_{SECRET}"),
                kind: 12,
                range: range(),
                selection_range: range(),
                children: Some(vec![Symbol {
                    name: format!("child_{SECRET}"),
                    kind: 12,
                    range: range(),
                    selection_range: range(),
                    children: None,
                }]),
            }],
            positions_degraded: None,
        };
        let mut item = HierarchyItem {
            name: format!("call_{SECRET}"),
            kind: 12,
            detail: Some(format!("detail {SECRET}")),
            uri: format!("file:///{SECRET}.rs"),
            range: range(),
            selection_range: range(),
            data: Some(serde_json::json!({ "id": SECRET })),
            out_of_workspace: false,
        };
        let mut type_item = HierarchyItem {
            name: format!("type_{SECRET}"),
            kind: 5,
            detail: None,
            uri: format!("file:///{SECRET}.rs"),
            range: range(),
            selection_range: range(),
            data: None,
            out_of_workspace: false,
        };
        let before = (
            serde_json::to_string(&symbols).unwrap(),
            serde_json::to_string(&item).unwrap(),
            serde_json::to_string(&type_item).unwrap(),
        );

        symbols.redact_server_text(&set);
        item.redact_server_text(&set);
        type_item.redact_server_text(&set);

        let after = (
            serde_json::to_string(&symbols).unwrap(),
            serde_json::to_string(&item).unwrap(),
            serde_json::to_string(&type_item).unwrap(),
        );
        assert_eq!(before, after);
    }

    #[test]
    fn test_server_text_with_no_secrets_rewrites_nothing() {
        let mut hover = HoverResult {
            contents: format!("doc {SECRET}"),
            range: None,
            positions_degraded: None,
        };

        hover.redact_server_text(&Redactions::default());

        assert_eq!(hover.contents, format!("doc {SECRET}"));
    }

    #[test]
    fn test_server_text_does_not_touch_already_redacted_diagnostics() {
        let set = Redactions::new([("API_TOKEN".to_owned(), SECRET.to_owned())]);
        let mut result = DocumentDiagnosticsResult {
            diagnostics: vec![ContextualDiagnostic::from(Diagnostic {
                range: range(),
                severity: ReportedSeverity::Error,
                message: format!("echo {SECRET}"),
                code: None,
            })],
            positions_degraded: None,
            enrichment: None,
        };

        result.redact_server_text(&set);

        assert_eq!(result.diagnostics[0].message, format!("echo {SECRET}"));
    }

    #[test]
    fn test_server_text_redacts_hover_and_prepare_rename_message() {
        let set = Redactions::new([("API_TOKEN".to_owned(), SECRET.to_owned())]);
        let mut hover = HoverResult {
            contents: format!("doc {SECRET}"),
            range: None,
            positions_degraded: None,
        };
        let mut outcome = PrepareRenameOutcome::NotRenameable {
            server_message: Some(format!("no {SECRET}")),
        };

        hover.redact_server_text(&set);
        outcome.redact_server_text(&set);

        assert_eq!(hover.contents, "doc [redacted:API_TOKEN]");
        assert_eq!(
            outcome,
            PrepareRenameOutcome::NotRenameable {
                server_message: Some("no [redacted:API_TOKEN]".to_owned())
            }
        );
    }

    #[test]
    fn test_position_degradation_request_outranks_response() {
        assert!(PositionDegradation::Request > PositionDegradation::Response);
        assert_eq!(
            Some(PositionDegradation::Response).max(Some(PositionDegradation::Request)),
            Some(PositionDegradation::Request)
        );
        assert_eq!(
            None.max(Some(PositionDegradation::Response)),
            Some(PositionDegradation::Response)
        );
    }

    #[test]
    fn test_position_degradation_serializes_as_snake_case_string() {
        assert_eq!(
            serde_json::to_value(PositionDegradation::Request).unwrap(),
            "request"
        );
        assert_eq!(
            serde_json::to_value(PositionDegradation::Response).unwrap(),
            "response"
        );
    }

    #[test]
    fn test_positions_degraded_key_omitted_when_none() {
        let result = super::DocumentSymbolsResult {
            symbols: Vec::new(),
            positions_degraded: None,
        };
        let value = serde_json::to_value(&result).unwrap();
        assert!(value.get("positions_degraded").is_none());

        let result = super::DocumentSymbolsResult {
            positions_degraded: Some(PositionDegradation::Response),
            ..result
        };
        let value = serde_json::to_value(&result).unwrap();
        assert_eq!(value["positions_degraded"], "response");
    }

    /// #467 regression: the old `Option<u8>` narrowing silently dropped any
    /// `InlayHintKind::Custom(n)` with `n > 255` to `None`, indistinguishable
    /// from "server sent no kind". `lsp_kind_to_u32` must preserve the full
    /// `u32` value losslessly.
    #[test]
    fn test_lsp_kind_to_u32_preserves_custom_values_above_u8_range() {
        let kind = lsp_types::InlayHintKind::Custom(300);
        assert_eq!(lsp_kind_to_u32(kind), 300u32);
    }

    #[test]
    fn test_position_from_client_bounds() {
        assert_eq!(Position::from_client(0, 1), Err(InvalidPosition::ZeroBased));
        assert_eq!(Position::from_client(1, 0), Err(InvalidPosition::ZeroBased));
        assert_eq!(
            Position::from_client(MAX_POSITION_VALUE + 1, 1),
            Err(InvalidPosition::TooLarge)
        );
        assert_eq!(
            Position::from_client(1, MAX_POSITION_VALUE + 1),
            Err(InvalidPosition::TooLarge)
        );
        let max = Position::from_client(MAX_POSITION_VALUE, MAX_POSITION_VALUE).unwrap();
        assert_eq!((max.lsp_line(), max.lsp_character()), (999_999, 999_999));
    }

    #[test]
    fn test_position_from_output_position_is_not_capped_and_clamps_zero() {
        let big = Position::from_server_output(&Position2D {
            line: MAX_POSITION_VALUE + 7,
            character: 2_000_000,
        });
        assert_eq!(big.line().get(), MAX_POSITION_VALUE + 7);
        let clamped = Position::from_server_output(&Position2D {
            line: 0,
            character: 0,
        });
        assert_eq!((clamped.line().get(), clamped.character().get()), (1, 1));
    }

    #[test]
    fn test_position_range_orders_and_bounds() {
        let at = Position::at;
        assert!(PositionRange::new(at(1, 5), at(1, 5)).is_ok());
        assert_eq!(
            PositionRange::new(at(2, 1), at(1, 9)),
            Err(InvalidRange::Reversed)
        );
        assert_eq!(
            PositionRange::new(at(1, 5), at(1, 4)),
            Err(InvalidRange::Reversed)
        );
        assert_eq!(
            PositionRange::from_client((0, 1), (1, 1)),
            Err(InvalidRange::Start(InvalidPosition::ZeroBased))
        );
        assert_eq!(
            PositionRange::from_client((1, 1), (1, 0)),
            Err(InvalidRange::End(InvalidPosition::ZeroBased))
        );

        let within = PositionRange::new(at(1, 1), at(1 + MAX_RANGE_LINES, 1)).unwrap();
        assert!(BoundedRange::try_from(within).is_ok());
        let beyond = PositionRange::new(at(1, 1), at(2 + MAX_RANGE_LINES, 1)).unwrap();
        assert_eq!(
            BoundedRange::try_from(beyond),
            Err(InvalidRange::TooManyLines)
        );
    }

    #[test]
    fn test_folding_kind_schema_lists_exactly_the_serde_names() {
        let kinds = |k: FoldingKind| match k {
            FoldingKind::Comment
            | FoldingKind::Imports
            | FoldingKind::Region
            | FoldingKind::Unspecified => k,
        };
        let variants = [
            FoldingKind::Comment,
            FoldingKind::Imports,
            FoldingKind::Region,
            FoldingKind::Unspecified,
        ]
        .map(kinds);
        let mut generator = schemars::SchemaGenerator::default();
        let schema = FoldingKind::json_schema(&mut generator);
        let listed: Vec<String> = schema
            .get("enum")
            .unwrap()
            .as_array()
            .unwrap()
            .iter()
            .map(|name| name.as_str().unwrap().to_owned())
            .collect();
        let serialized: Vec<String> = variants
            .iter()
            .map(|k| {
                serde_json::to_value(k)
                    .unwrap()
                    .as_str()
                    .unwrap()
                    .to_owned()
            })
            .collect();
        assert_eq!(listed, serialized);
    }

    #[test]
    fn test_folding_kind_filter_schema_lists_exactly_the_serde_names() {
        let filters = |f: FoldingKindFilter| match f {
            FoldingKindFilter::All
            | FoldingKindFilter::Comment
            | FoldingKindFilter::Imports
            | FoldingKindFilter::Region => f,
        };
        let variants = FoldingKindFilter::ALL.map(filters);
        let schema = FoldingKindFilter::schema();
        let listed: Vec<FoldingKindFilter> = schema
            .get("enum")
            .unwrap()
            .as_array()
            .unwrap()
            .iter()
            .map(|name| FoldingKindFilter::parse(name.as_str().unwrap()).unwrap())
            .collect();
        assert_eq!(listed, variants);
        assert_eq!(
            FoldingKindFilter::parse("IMPORTS"),
            Some(FoldingKindFilter::Imports)
        );
        assert_eq!(FoldingKindFilter::parse("unspecified"), None);
    }

    #[test]
    fn test_folding_collapsed_text_is_redacted_before_it_is_cut() {
        use crate::redaction::{Redactions, ServerText as _};

        let secret = "bravo-secret-222";
        let redactions = Redactions::new([("B_TOKEN".to_owned(), secret.to_owned())]);
        let straddling = format!("{}{secret}tail", "x".repeat(MAX_COLLAPSED_TEXT_BYTES - 8));
        let region = |text: String| FoldingRegion {
            start_line: 1,
            end_line: 2,
            start_character: None,
            end_character: None,
            kind: FoldingKind::Region,
            collapsed_text: Some(text),
        };
        let mut result = FoldingRangesResult {
            regions: vec![region(straddling), region("short".to_string())],
            truncated: false,
            positions_degraded: None,
        };

        result.redact_server_text(&redactions);

        let text = result.regions[0].collapsed_text.as_deref().unwrap();
        assert!(!text.contains("bravo"), "{text}");
        assert!(text.ends_with("... (truncated)"), "{text}");
        assert!(text.len() <= MAX_COLLAPSED_TEXT_BYTES + "... (truncated)".len());
        assert_eq!(result.regions[1].collapsed_text.as_deref(), Some("short"));
    }
}