vct-core 2.4.1

//! Persistent user settings (`~/.vct/config.toml`).
//!
//! A small typed [`Config`] read with serde and written back with `toml_edit`
//! so hand-added comments and any unknown keys survive programmatic edits (the
//! same "preserve what we don't own" idea as the credential write-back in
//! `quota::refresh`). Reads are infallible: a missing or malformed file falls
//! back to defaults.
//!
//! The typed structs are the single source of truth: their `#[serde(default)]`
//! values and `///` doc-comments feed both the JSON schema (via `schemars`) and
//! the commented default `config.toml` (generated by [`default_document`]), so
//! there is no hand-maintained template to drift. On the first run the generated
//! file is materialized with a `#:schema` directive pointing at the published
//! schema so schema-aware editors validate it.
//!
//! Files written by an older vct are upgraded through two layers. On load,
//! [`migrate_document`] rewrites a standard-`[header]`-table file in place —
//! adding the `#:schema` directive, renaming `refresh_interval_secs` to
//! `refresh_interval`, and moving `[usage].quota_panels` into the nested
//! `[usage.quota]` table — so an existing user actually gets the new layout
//! (`vct config migrate` forces the same pass). A read-time [`migrate_legacy`]
//! shim then backstops any residual legacy form the structural pass leaves alone
//! (e.g. a hand-edited inline `usage = { ... }` table), so the returned [`Config`]
//! is always correct even when the file was not rewritten.

use crate::models::TimeRange;
use crate::utils::{get_cache_dir, write_string_atomic};
use anyhow::Result;
use schemars::JsonSchema;
use serde::{Deserialize, Serialize};
use serde_json::Value;
use std::path::Path;
use toml_edit::{Array, DocumentMut, Item, Table, TableLike, value};

/// URL of the published JSON schema, referenced via a `#:schema` directive on
/// the first line of the generated `config.toml` so schema-aware TOML editors
/// (taplo / VS Code "Even Better TOML") offer autocomplete and validation.
const SCHEMA_URL: &str =
    "https://raw.githubusercontent.com/Mai0313/VibeCodingTracker/main/vct.schema.json";

/// Current layout version of `config.toml`, stamped into `[general].version`.
///
/// It exists so an upgrade can add a setting to an existing file exactly once.
/// Version 1 is any file written before the key existed.
const CONFIG_VERSION: u32 = 2;

/// Quota panels introduced after version 1, back-filled once into a file older
/// than the version that shipped them.
///
/// Only the panel a given version *added* is back-filled, so a panel the user
/// removed on purpose earlier is never resurrected. Extend this list (and bump
/// [`CONFIG_VERSION`]) when a new provider gains a panel.
const PANELS_ADDED_BY_VERSION: &[(u32, &str)] = &[(2, "grok")];

/// The full settings document.
#[derive(Debug, Clone, PartialEq, Default, Serialize, Deserialize, JsonSchema)]
pub struct Config {
    #[serde(default)]
    pub general: GeneralConfig,
    #[serde(default)]
    pub usage: UsageConfig,
    #[serde(default)]
    pub analysis: AnalysisConfig,
    #[serde(default)]
    pub performance: PerformanceConfig,
    #[serde(default)]
    pub providers: ProvidersConfig,
    #[serde(default)]
    pub logging: LoggingConfig,
}

/// `[performance]` - controls for CPU-bound local scans.
#[derive(Debug, Clone, Copy, PartialEq, Eq, Default, Serialize, Deserialize, JsonSchema)]
pub struct PerformanceConfig {
    /// Rayon workers used by CLI session scans. `0` selects the measured auto
    /// default; a positive value is capped at the machine's available parallelism.
    #[serde(default)]
    pub scan_threads: usize,
}

impl PerformanceConfig {
    /// Resolves the CLI scan worker count.
    ///
    /// A positive config value wins, followed by a positive
    /// `RAYON_NUM_THREADS`; otherwise auto mode uses at most two workers. Every
    /// result is capped at the available parallelism and is at least one.
    pub fn resolved_scan_threads(&self) -> usize {
        let available = std::thread::available_parallelism()
            .map(std::num::NonZeroUsize::get)
            .unwrap_or(1);
        self.resolved_scan_threads_with(
            available,
            std::env::var("RAYON_NUM_THREADS").ok().as_deref(),
        )
    }

    fn resolved_scan_threads_with(&self, available: usize, rayon_env: Option<&str>) -> usize {
        let available = available.max(1);
        let requested = if self.scan_threads > 0 {
            self.scan_threads
        } else {
            rayon_env
                .and_then(|value| value.parse::<usize>().ok())
                .filter(|value| *value > 0)
                .unwrap_or_else(|| available.min(2))
        };
        requested.clamp(1, available)
    }
}

/// `[general]` — settings shared across subcommands.
#[derive(Debug, Clone, PartialEq, Serialize, Deserialize, JsonSchema)]
pub struct GeneralConfig {
    /// Default time range when no --daily/--weekly/--monthly/--all flag is given.
    /// One of: "daily" | "weekly" | "monthly" | "all".
    #[serde(default)]
    pub default_time_range: TimeRange,
    /// Layout version of this file, stamped by vct. Only the upgrade pass reads
    /// it; leave it alone unless you want a past upgrade to run again.
    #[serde(
        default = "legacy_config_version",
        deserialize_with = "de_config_version"
    )]
    pub version: u32,
}

impl Default for GeneralConfig {
    fn default() -> Self {
        Self {
            default_time_range: TimeRange::default(),
            // A file this tool writes is current by construction; only a file
            // read from disk without the key is legacy (see the serde default).
            version: CONFIG_VERSION,
        }
    }
}

/// `[usage]` — usage dashboard preferences.
#[derive(Debug, Clone, PartialEq, Serialize, Deserialize, JsonSchema)]
pub struct UsageConfig {
    /// Start the usage dashboard with models merged across provider prefixes.
    /// Toggled live with `m`; the last state is saved back here.
    #[serde(default)]
    pub merge_models: bool,
    /// Seconds between automatic redraws of the usage TUI (minimum 1).
    #[serde(default = "default_refresh_secs")]
    pub refresh_interval: u64,
    /// Live quota-panel preferences.
    #[serde(default)]
    pub quota: QuotaConfig,
}

impl Default for UsageConfig {
    fn default() -> Self {
        Self {
            merge_models: false,
            refresh_interval: default_refresh_secs(),
            quota: QuotaConfig::default(),
        }
    }
}

impl UsageConfig {
    /// The usage TUI redraw cadence, clamped to a sane minimum so a `0` cannot
    /// busy-loop.
    pub fn refresh_secs(&self) -> u64 {
        self.refresh_interval.max(1)
    }

    /// The live quota-panel poll cadence, clamped to a sane minimum.
    pub fn quota_refresh_secs(&self) -> u64 {
        self.quota.refresh_interval.max(1)
    }

    /// Whether the quota panel for `provider` is enabled (case-insensitive).
    pub fn shows_quota_panel(&self, provider: &str) -> bool {
        quota_panel_selected(&self.quota.panels, provider)
    }
}

/// `[usage.quota]` — live quota-panel preferences.
#[derive(Debug, Clone, PartialEq, Serialize, Deserialize, JsonSchema)]
pub struct QuotaConfig {
    /// Which live quota panels to show in the usage TUI (by provider name:
    /// `claude` / `codex` / `copilot` / `cursor` / `grok`). An empty list hides
    /// every quota card; the Provider Usage pane has its own `p` toggle.
    #[serde(default = "default_quota_panels")]
    pub panels: Vec<String>,
    /// Seconds between live quota-panel polls, shared by every provider
    /// (minimum 1). Higher is safer against a provider's rate limits.
    #[serde(default = "default_quota_refresh_secs")]
    pub refresh_interval: u64,
}

impl Default for QuotaConfig {
    fn default() -> Self {
        Self {
            panels: default_quota_panels(),
            refresh_interval: default_quota_refresh_secs(),
        }
    }
}

/// Whether `name` is one of the selected quota-panel names (case-insensitive).
///
/// The single home for the panel-selection rule, shared by
/// [`UsageConfig::shows_quota_panel`] and the usage TUI's panel masking.
pub fn quota_panel_selected(panels: &[String], name: &str) -> bool {
    panels.iter().any(|p| p.eq_ignore_ascii_case(name))
}

/// `[analysis]` — analysis dashboard preferences.
#[derive(Debug, Clone, PartialEq, Serialize, Deserialize, JsonSchema)]
pub struct AnalysisConfig {
    /// Seconds between automatic redraws of the analysis TUI (minimum 1).
    #[serde(default = "default_refresh_secs")]
    pub refresh_interval: u64,
}

impl Default for AnalysisConfig {
    fn default() -> Self {
        Self {
            refresh_interval: default_refresh_secs(),
        }
    }
}

impl AnalysisConfig {
    /// The refresh cadence, clamped to a sane minimum so a `0` cannot busy-loop.
    pub fn refresh_secs(&self) -> u64 {
        self.refresh_interval.max(1)
    }
}

/// `[providers]` — per-provider include toggles.
///
/// Each provider defaults to `true`; setting one to `false` skips it entirely
/// (no directory scan, no API) in both the usage and analysis roll-ups.
#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize, JsonSchema)]
pub struct ProvidersConfig {
    #[serde(default = "default_true")]
    pub claude: bool,
    #[serde(default = "default_true")]
    pub codex: bool,
    #[serde(default = "default_true")]
    pub copilot: bool,
    #[serde(default = "default_true")]
    pub gemini: bool,
    #[serde(default = "default_true")]
    pub opencode: bool,
    #[serde(default = "default_true")]
    pub cursor: bool,
    #[serde(default = "default_true")]
    pub hermes: bool,
    #[serde(default = "default_true")]
    pub grok: bool,
}

impl Default for ProvidersConfig {
    fn default() -> Self {
        Self {
            claude: true,
            codex: true,
            copilot: true,
            gemini: true,
            opencode: true,
            cursor: true,
            hermes: true,
            grok: true,
        }
    }
}

/// `[logging]` — file logging preferences.
///
/// Diagnostics are written to `~/.vct/logs/vct-YYYY-MM-DD.log` (plain text, one
/// line per record). Nothing is ever printed to the terminal, so the TUI is
/// never disturbed. The log file is created lazily on the first record, so a
/// command that logs nothing never touches `~/.vct`.
#[derive(Debug, Clone, PartialEq, Serialize, Deserialize, JsonSchema)]
pub struct LoggingConfig {
    /// Minimum level written to the log file.
    /// One of: "off" | "error" | "warn" | "info" | "debug" | "trace".
    #[serde(default)]
    pub level: LogLevel,
    /// Days of daily log files to keep; older `vct-*.log` files are pruned on
    /// startup. `0` keeps every file.
    #[serde(default = "default_log_retention_days")]
    pub retention_days: u32,
}

impl Default for LoggingConfig {
    fn default() -> Self {
        Self {
            level: LogLevel::default(),
            retention_days: default_log_retention_days(),
        }
    }
}

/// Minimum severity written to the log file.
#[derive(Debug, Clone, Copy, Default, PartialEq, Eq, Serialize, Deserialize, JsonSchema)]
#[serde(rename_all = "lowercase")]
pub enum LogLevel {
    /// Disable file logging entirely.
    Off,
    /// Only errors.
    Error,
    /// Errors and warnings (the default — quiet when healthy, records problems).
    #[default]
    Warn,
    /// Adds high-level informational breadcrumbs.
    Info,
    /// Adds verbose diagnostics (per-file parse skips, quota poll detail).
    Debug,
    /// Everything, including cache-hit traces.
    Trace,
}

fn default_true() -> bool {
    true
}

fn default_log_retention_days() -> u32 {
    7
}

fn default_refresh_secs() -> u64 {
    10
}

fn default_quota_refresh_secs() -> u64 {
    60
}

/// The version a file carrying no `[general].version` key predates.
fn legacy_config_version() -> u32 {
    1
}

/// Reads the version marker, mapping a hand-edited non-integer (`version = "2"`)
/// onto the legacy value instead of rejecting it.
///
/// Rejection would fail the whole document, and the infallible read then turns
/// that into a silent reset of every setting — the same trap
/// [`rename_refresh_key`] drops malformed values to avoid. Reading it as legacy
/// makes the upgrade pass rewrite the key with a real integer.
fn de_config_version<'de, D>(deserializer: D) -> Result<u32, D::Error>
where
    D: serde::Deserializer<'de>,
{
    Ok(Value::deserialize(deserializer)
        .ok()
        .and_then(|v| v.as_u64())
        .and_then(|n| u32::try_from(n).ok())
        .unwrap_or_else(legacy_config_version))
}

fn default_quota_panels() -> Vec<String> {
    ["claude", "codex", "copilot", "cursor", "grok"]
        .iter()
        .map(|s| s.to_string())
        .collect()
}

/// Loads settings from `~/.vct/config.toml`, creating it with defaults on first
/// run.
///
/// Infallible: any error resolving, reading, or parsing degrades to
/// [`Config::default`].
pub fn load() -> Config {
    match get_cache_dir() {
        Ok(dir) => load_in(&dir),
        Err(_) => Config::default(),
    }
}

/// [`load`] rooted at an explicit directory (test seam).
pub fn load_in(dir: &Path) -> Config {
    let path = dir.join("config.toml");
    if path.exists() {
        let Ok(text) = std::fs::read_to_string(&path) else {
            return Config::default();
        };
        // Auto-migrate a legacy-format file in place so existing users pick up the
        // renamed keys, the `[usage.quota]` nesting, and the `#:schema` directive.
        // Best-effort: a failed write (e.g. a read-only home) still yields a
        // correct in-memory Config below. Malformed TOML is never overwritten.
        let effective = match migrate_text(&text) {
            Ok(Some(migrated)) => {
                let _ = write_string_atomic(&path, &migrated);
                migrated
            }
            Ok(None) => text,
            Err(_) => return Config::default(),
        };
        let mut config: Config = toml_edit::de::from_str(&effective).unwrap_or_default();
        // Backstop for any residual legacy form the structural migration leaves
        // alone (e.g. an inline `usage = { ... }` table).
        migrate_legacy(&mut config, &effective);
        return config;
    }
    // First run: materialize the generated commented template.
    let text = default_document().to_string();
    let _ = write_string_atomic(&path, &text);
    toml_edit::de::from_str(&text).unwrap_or_default()
}

/// Outcome of an explicit [`migrate_config_file`] run, surfaced by
/// `vct config migrate`.
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum MigrationStatus {
    /// No file existed, so a fresh commented default was written.
    Created,
    /// A legacy-format file was rewritten to the current on-disk format.
    Migrated,
    /// The file was already current; nothing was written.
    AlreadyCurrent,
}

/// Migrates the `config.toml` at `path` to the current on-disk format in place,
/// creating the commented default when the file is absent. Shared by
/// `vct config migrate` and the auto-migration in [`load_in`].
pub fn migrate_config_file(path: &Path) -> Result<MigrationStatus> {
    if !path.exists() {
        write_string_atomic(path, &default_document().to_string())?;
        return Ok(MigrationStatus::Created);
    }
    let text = std::fs::read_to_string(path)?;
    match migrate_text(&text)? {
        Some(migrated) => {
            write_string_atomic(path, &migrated)?;
            Ok(MigrationStatus::Migrated)
        }
        None => Ok(MigrationStatus::AlreadyCurrent),
    }
}

/// Applies the structural migration to raw config text: `Ok(Some(new))` when it
/// changed, `Ok(None)` when already current, `Err` when the text is not valid
/// TOML (so a caller never overwrites an unparseable file with defaults).
pub fn migrate_text(text: &str) -> Result<Option<String>> {
    let mut doc: DocumentMut = text.parse()?;
    Ok(migrate_document(&mut doc).then(|| doc.to_string()))
}

/// Read-time backstop for config files written before quota settings moved into
/// `[usage.quota]`: an old `[usage].quota_panels` key is honored when the new
/// `[usage.quota].panels` key is absent, and a legacy `refresh_interval_secs` is
/// mapped onto `refresh_interval`. The on-disk file is normally rewritten by
/// [`migrate_document`] first; this shim only has to cover the forms that pass
/// leaves alone (e.g. an inline `usage = { ... }` table), keeping the in-memory
/// [`Config`] correct even when the file itself was not upgraded.
fn migrate_legacy(config: &mut Config, raw: &str) {
    let Ok(doc) = raw.parse::<DocumentMut>() else {
        return;
    };
    if let Some(usage) = doc.get("usage").and_then(Item::as_table_like) {
        // [usage].quota_panels -> [usage.quota].panels. A present new key (even
        // `panels = []`) always wins over the legacy one.
        let has_new_panels = usage
            .get("quota")
            .and_then(Item::as_table_like)
            .is_some_and(|q| q.contains_key("panels"));
        if !has_new_panels && let Some(legacy) = usage.get("quota_panels").and_then(Item::as_array)
        {
            config.usage.quota.panels = legacy
                .iter()
                .filter_map(|v| v.as_str().map(str::to_string))
                .collect();
        }
        migrate_refresh_secs(usage, &mut config.usage.refresh_interval);
    }
    if let Some(analysis) = doc.get("analysis").and_then(Item::as_table_like) {
        migrate_refresh_secs(analysis, &mut config.analysis.refresh_interval);
    }
}

/// Honors a legacy `refresh_interval_secs` when the new `refresh_interval` key
/// is absent from the section. This replaces a serde `alias`, which would make
/// serde reject a mid-upgrade file carrying *both* names as a duplicate field
/// and (via the infallible read) silently reset the whole config to defaults.
fn migrate_refresh_secs(section: &dyn TableLike, target: &mut u64) {
    if !section.contains_key("refresh_interval")
        && let Some(secs) = section
            .get("refresh_interval_secs")
            .and_then(Item::as_integer)
        && let Ok(v) = u64::try_from(secs)
    {
        *target = v;
    }
}

/// Structural on-disk migration for a `config.toml` written by an older vct.
///
/// Operates on standard `[header]` tables only — an inline `usage = { ... }`
/// table is left to the read-time [`migrate_legacy`] shim, so this never has to
/// synthesize a header table inside an inline one. Returns whether anything
/// changed, so the caller rewrites the file at most once. Idempotent:
/// re-running on an already-migrated document returns `false`.
fn migrate_document(doc: &mut DocumentMut) -> bool {
    let schema = json_schema();
    let mut changed = false;

    // `[usage]`: rename the refresh key, then move quota_panels into the nested
    // `[usage.quota]`. Quota goes last so its `[usage.quota]` header renders
    // after every leaf key of `[usage]` (a leaf after a sub-table would be
    // invalid TOML).
    if doc.get("usage").is_some_and(Item::is_table) {
        if let Some(usage) = doc.get_mut("usage").and_then(Item::as_table_mut) {
            changed |= rename_refresh_key(usage, &schema, &["usage", "refresh_interval"]);
        }
        changed |= migrate_quota_panels(doc, &schema);
    }

    // `[analysis]`: rename the refresh key.
    if let Some(analysis) = doc.get_mut("analysis").and_then(Item::as_table_mut) {
        changed |= rename_refresh_key(analysis, &schema, &["analysis", "refresh_interval"]);
    }

    // Runs after the moves above so it sees the panel list they may have just
    // relocated into `[usage.quota]`.
    changed |= backfill_new_quota_panels(doc, &schema);

    // The `#:schema` directive on the first line drives editor autocomplete. It
    // attaches to the document's first element, so it goes last: on an empty
    // file the back-fill above is what creates that first element, and running
    // earlier would leave the directive to a second pass.
    if !has_schema_directive(doc) {
        changed |= prepend_schema_directive(doc);
    }

    changed
}

/// Adds quota panels that shipped after this file was written, exactly once.
///
/// The one-shot guarantee is `[general].version`: a file predating a panel is
/// missing it because the panel did not exist yet, not because the user removed
/// it — but only until the marker is stamped, after which a removal sticks.
/// Only the panels a version *added* are considered, so a panel the user
/// dropped before this upgrade is never resurrected either.
///
/// Two cases are deliberately left alone: an empty `panels` list (the band was
/// turned off on purpose) and a file whose `[general]` is an inline table (the
/// marker could not be written, so back-filling could not stay one-shot).
fn backfill_new_quota_panels(doc: &mut DocumentMut, schema: &Value) -> bool {
    let from_version = match doc.get("general") {
        Some(item) => {
            let Some(general) = item.as_table() else {
                // Inline `general = { ... }`: no place to stamp the marker.
                return false;
            };
            general
                .get("version")
                .and_then(Item::as_integer)
                .and_then(|v| u32::try_from(v).ok())
                .unwrap_or_else(legacy_config_version)
        }
        None => legacy_config_version(),
    };
    if from_version >= CONFIG_VERSION {
        return false;
    }

    // The list lives inside an inline table this pass never rewrites, so it
    // cannot be back-filled — and stamping the marker anyway would retire the
    // upgrade without having run it.
    if panels_out_of_reach(doc) {
        return false;
    }

    if let Some(panels) = doc
        .get_mut("usage")
        .and_then(Item::as_table_mut)
        .and_then(|usage| usage.get_mut("quota"))
        .and_then(Item::as_table_mut)
        .and_then(|quota| quota.get_mut("panels"))
        .and_then(Item::as_array_mut)
        // An empty list hides the whole band; adding to it would undo that.
        .filter(|panels| !panels.is_empty())
    {
        let missing: Vec<&str> = PANELS_ADDED_BY_VERSION
            .iter()
            .filter(|(version, _)| from_version < *version)
            .map(|(_, name)| *name)
            .filter(|name| {
                !panels
                    .iter()
                    .filter_map(|p| p.as_str())
                    .any(|p| p.eq_ignore_ascii_case(name))
            })
            .collect();
        for name in missing {
            panels.push(name);
        }
    }

    stamp_config_version(doc, schema);
    true
}

/// Whether the effective panel list sits inside an inline table.
///
/// [`migrate_document`] deliberately leaves inline tables alone, so such a list
/// can be neither read nor extended here — the read-time [`migrate_legacy`] shim
/// is what keeps it working. A file without a panel list at all is *not* out of
/// reach: it simply picks up the current default, new names included.
fn panels_out_of_reach(doc: &DocumentMut) -> bool {
    let Some(usage) = doc.get("usage") else {
        return false;
    };
    let holds_panels = |table: &dyn TableLike| {
        table.contains_key("quota_panels")
            || table
                .get("quota")
                .and_then(Item::as_table_like)
                .is_some_and(|quota| quota.contains_key("panels"))
    };
    match usage.as_table() {
        // `usage = { ... }`: nothing under it can be rewritten.
        None => usage.as_table_like().is_some_and(holds_panels),
        Some(usage) => {
            // A standard `[usage]` whose `quota` child is inline.
            let inline_quota = usage
                .get("quota")
                .filter(|quota| !quota.is_table())
                .and_then(Item::as_table_like)
                .is_some_and(|quota| quota.contains_key("panels"));
            // Or a legacy `quota_panels` that `migrate_quota_panels` declined to
            // move (it also refuses an inline `quota` sibling), which leaves the
            // effective list somewhere this pass cannot extend.
            inline_quota || usage.contains_key("quota_panels")
        }
    }
}

/// Writes `[general].version` (creating the table when a hand-written file has
/// no `[general]` section at all).
fn stamp_config_version(doc: &mut DocumentMut, schema: &Value) {
    if doc.get("general").is_none() {
        let mut table = Table::new();
        table.set_implicit(false);
        if let Some(desc) = schema_description(schema, &["general"]) {
            table
                .decor_mut()
                .set_prefix(format!("\n{}", comment_block(&desc)));
        }
        doc.insert("general", Item::Table(table));
    }
    let Some(general) = doc.get_mut("general").and_then(Item::as_table_mut) else {
        return;
    };
    let had_key = general.contains_key("version");
    general.insert("version", value(i64::from(CONFIG_VERSION)));
    if !had_key {
        apply_comment(general, "version", "", schema, &["general", "version"]);
    }
}

/// Whether the document already carries a `#:schema` directive line.
fn has_schema_directive(doc: &DocumentMut) -> bool {
    // Only the first non-blank line can be a real directive; scanning every line
    // would false-positive on a `#:schema`-prefixed line buried inside a
    // multi-line string value or a later comment, wrongly skipping the prepend.
    doc.to_string()
        .lines()
        .find(|line| !line.trim().is_empty())
        .is_some_and(|line| line.trim_start().starts_with("#:schema"))
}

/// Prepends the `#:schema` directive to the document's leading trivia (the
/// prefix decor of its first element). Returns whether it was added.
fn prepend_schema_directive(doc: &mut DocumentMut) -> bool {
    let directive = format!("#:schema {SCHEMA_URL}\n");
    let root = doc.as_table_mut();
    let Some(first_key) = root.iter().next().map(|(k, _)| k.to_string()) else {
        return false;
    };
    if let Some(item) = root.get_mut(&first_key)
        && let Some(table) = item.as_table_mut()
    {
        let existing = decor_prefix(table.decor());
        table
            .decor_mut()
            .set_prefix(format!("{directive}{existing}"));
        return true;
    }
    if let Some(mut km) = root.key_mut(&first_key) {
        let existing = decor_prefix(km.leaf_decor());
        km.leaf_decor_mut()
            .set_prefix(format!("{directive}{existing}"));
        return true;
    }
    false
}

/// The existing prefix text of a decor, or an empty string.
fn decor_prefix(decor: &toml_edit::Decor) -> String {
    decor
        .prefix()
        .and_then(|p| p.as_str())
        .unwrap_or("")
        .to_string()
}

/// Within `table`, migrate a legacy `refresh_interval_secs` to the current
/// `refresh_interval`: rename when only the old key is present, or drop the old
/// key when both coexist (a mid-upgrade file where the new key already wins).
///
/// A malformed legacy value (negative, float, string) is **dropped**, not
/// promoted: writing it into the typed `refresh_interval` field would make serde
/// reject the whole migrated file and silently reset every setting to defaults.
/// Dropping it lets the typed default apply, matching the pre-migration read.
fn rename_refresh_key(table: &mut Table, schema: &Value, comment_path: &[&str]) -> bool {
    if !table.contains_key("refresh_interval_secs") {
        return false;
    }
    // Both present: the new key already wins on read, so just drop the stale one.
    if table.contains_key("refresh_interval") {
        table.remove("refresh_interval_secs");
        return true;
    }
    let Some((old_key, item)) = table.remove_entry("refresh_interval_secs") else {
        return false;
    };
    if let Some(secs) = item.as_integer().and_then(|n| u64::try_from(n).ok()) {
        table.insert("refresh_interval", value(secs as i64));
        // Keep a hand-added comment; otherwise apply the current schema comment.
        let existing = decor_prefix(old_key.leaf_decor());
        apply_comment(table, "refresh_interval", &existing, schema, comment_path);
    }
    true
}

/// Moves a legacy top-level `[usage].quota_panels` array into the nested
/// `[usage.quota].panels`, creating the `[usage.quota]` table (with the current
/// default `refresh_interval`) when needed. A present `[usage.quota].panels`
/// wins; the legacy key is removed once handled. An inline `quota = { ... }`
/// child is left untouched (legacy key preserved) so no data is lost trying to
/// merge into an inline table.
fn migrate_quota_panels(doc: &mut DocumentMut, schema: &Value) -> bool {
    let Some(usage) = doc.get("usage").and_then(Item::as_table) else {
        return false;
    };
    if !usage.contains_key("quota_panels") {
        return false;
    }
    if usage.get("quota").is_some_and(Item::is_inline_table) {
        return false;
    }
    let has_new_panels = usage
        .get("quota")
        .and_then(Item::as_table_like)
        .is_some_and(|q| q.contains_key("panels"));

    let usage = doc
        .get_mut("usage")
        .and_then(Item::as_table_mut)
        .expect("usage table present");
    let Some((old_key, old_item)) = usage.remove_entry("quota_panels") else {
        return false;
    };
    if has_new_panels {
        // The new `[usage.quota].panels` already wins; drop the legacy key only.
        return true;
    }
    let legacy_panels: Vec<String> = old_item
        .as_array()
        .map(|a| {
            a.iter()
                .filter_map(|v| v.as_str().map(str::to_string))
                .collect()
        })
        .unwrap_or_default();
    // Carry the legacy key's comment onto the new `panels` key.
    let comment = decor_prefix(old_key.leaf_decor());

    if usage.get("quota").and_then(Item::as_table).is_some() {
        // Existing `[usage.quota]` without a panels key: just add it.
        let quota = usage
            .get_mut("quota")
            .and_then(Item::as_table_mut)
            .expect("quota table present");
        quota.insert("panels", value(panels_array(&legacy_panels)));
        apply_comment(
            quota,
            "panels",
            &comment,
            schema,
            &["usage", "quota", "panels"],
        );
    } else {
        usage.insert(
            "quota",
            Item::Table(build_quota_table(&legacy_panels, &comment, schema)),
        );
    }
    true
}

/// A TOML array from a list of panel names.
fn panels_array(panels: &[String]) -> Array {
    panels.iter().map(String::as_str).collect()
}

/// Builds a fresh `[usage.quota]` table from the migrated panels (carrying the
/// legacy key's comment when it had one) and the current default
/// `refresh_interval`, which is brand-new so it gets the schema comment.
fn build_quota_table(panels: &[String], panels_comment: &str, schema: &Value) -> Table {
    let mut table = Table::new();
    table.set_implicit(false);
    if let Some(desc) = schema_description(schema, &["usage", "quota"]) {
        table
            .decor_mut()
            .set_prefix(format!("\n{}", comment_block(&desc)));
    }
    table.insert("panels", value(panels_array(panels)));
    apply_comment(
        &mut table,
        "panels",
        panels_comment,
        schema,
        &["usage", "quota", "panels"],
    );
    table.insert(
        "refresh_interval",
        value(default_quota_refresh_secs() as i64),
    );
    apply_comment(
        &mut table,
        "refresh_interval",
        "",
        schema,
        &["usage", "quota", "refresh_interval"],
    );
    table
}

/// Attaches a leading `#` comment to `key`, mirroring the leaf styling in
/// [`annotate_table`]: keeps a non-empty `existing` comment (a hand-added or
/// carried-over one), otherwise falls back to the field's schema `description`.
fn apply_comment(table: &mut Table, key: &str, existing: &str, schema: &Value, path: &[&str]) {
    let prefix = if existing.trim().is_empty() {
        schema_description(schema, path).map(|desc| format!("\n{}", comment_block(&desc)))
    } else {
        Some(existing.to_string())
    };
    if let Some(prefix) = prefix
        && let Some(mut km) = table.key_mut(key)
    {
        km.leaf_decor_mut().set_prefix(prefix);
    }
}

/// Walks the (inlined) JSON schema to a nested field's `description`.
fn schema_description(schema: &Value, path: &[&str]) -> Option<String> {
    let mut cur = schema;
    for key in path {
        cur = cur.get("properties")?.get(key)?;
    }
    cur.get("description")
        .and_then(Value::as_str)
        .map(str::to_string)
}

/// Persists the usage dashboard's merge toggle back to the config.
pub fn save_merge_models(enabled: bool) -> Result<()> {
    save_merge_models_in(&get_cache_dir()?, enabled)
}

/// [`save_merge_models`] rooted at an explicit directory (test seam).
pub fn save_merge_models_in(dir: &Path, enabled: bool) -> Result<()> {
    edit_in(dir, |doc| {
        // A hand-edited file could make `usage` a scalar (`usage = "bad"`);
        // replace any non-table-like value with an empty table so indexing into
        // it below cannot panic. `is_table_like` accepts both the `[usage]`
        // header form AND an inline table (`usage = { ... }`), so a valid config
        // in either form is left intact (its keys/comments preserved) — only a
        // genuine scalar is repaired.
        if !doc["usage"].is_table_like() {
            doc["usage"] = Item::Table(Table::new());
        }
        doc["usage"]["merge_models"] = value(enabled);
    })
}

/// Reads the current document (or the template when absent/malformed), applies
/// `mutate`, and writes it back atomically — preserving formatting and comments.
fn edit_in(dir: &Path, mutate: impl FnOnce(&mut DocumentMut)) -> Result<()> {
    let path = dir.join("config.toml");
    let mut doc = std::fs::read_to_string(&path)
        .ok()
        .and_then(|text| text.parse::<DocumentMut>().ok())
        .unwrap_or_else(default_document);
    mutate(&mut doc);
    write_string_atomic(&path, &doc.to_string())
}

/// The JSON schema for the settings file, used both by `vct config schema` and
/// to derive the commented default template. Subschemas are inlined so the
/// document is self-contained and each field's `description` is easy to walk.
pub fn json_schema() -> Value {
    let settings =
        schemars::generate::SchemaSettings::draft2020_12().with(|s| s.inline_subschemas = true);
    let schema = settings.into_generator().into_root_schema_for::<Config>();
    serde_json::to_value(&schema).expect("config schema serializes to JSON")
}

/// The pretty-printed JSON schema (the committed `vct.schema.json` body, also
/// what `vct config schema` prints). Ends with a trailing newline.
pub fn schema_json() -> String {
    let mut s = serde_json::to_string_pretty(&json_schema()).expect("schema serializes");
    s.push('\n');
    s
}

/// Builds the commented default `config.toml` document from the typed
/// [`Config`]: values come from [`Config::default`] (serialized via `toml_edit`),
/// per-key and per-section comments come from the schema `description`s, and the
/// `#:schema` directive is placed on the first line.
fn default_document() -> DocumentMut {
    let mut doc: DocumentMut = toml_edit::ser::to_string(&Config::default())
        .expect("default config serializes to TOML")
        .parse()
        .expect("serialized default config is valid TOML");
    let schema = json_schema();
    annotate_table(doc.as_table_mut(), &schema, true);
    doc
}

/// Recursively attaches each field's schema `description` as a leading `#`
/// comment to the matching key or sub-table of `table`. On the root table the
/// `#:schema` directive is prepended to the first section.
fn annotate_table(table: &mut Table, schema: &Value, is_root: bool) {
    let props = schema
        .get("properties")
        .and_then(Value::as_object)
        .cloned()
        .unwrap_or_default();
    let keys: Vec<String> = table.iter().map(|(k, _)| k.to_string()).collect();
    for (idx, key) in keys.iter().enumerate() {
        let field_schema = props.get(key);
        let desc = field_schema
            .and_then(|s| s.get("description"))
            .and_then(Value::as_str);
        let is_table = table
            .get(key)
            .is_some_and(|i| i.is_table() || i.is_inline_table());
        if is_table {
            let field_schema = field_schema.cloned();
            // The serializer suffixes every key with a space (right for a leaf's
            // `k = v`, but it renders a table header as `[usage ]`); trim it.
            if let Some(mut km) = table.key_mut(key) {
                km.leaf_decor_mut().set_suffix("");
            }
            if let Some(item) = table.get_mut(key)
                && let Some(sub) = as_standard_table(item)
            {
                let mut prefix = String::new();
                if is_root && idx == 0 {
                    prefix.push_str(&format!("#:schema {SCHEMA_URL}\n\n"));
                } else {
                    prefix.push('\n');
                }
                if let Some(d) = desc {
                    prefix.push_str(&comment_block(d));
                }
                sub.decor_mut().set_prefix(prefix);
                if let Some(fs) = field_schema {
                    annotate_table(sub, &fs, false);
                }
            }
        } else if let Some(d) = desc
            && let Some(mut km) = table.key_mut(key)
        {
            km.leaf_decor_mut()
                .set_prefix(format!("\n{}", comment_block(d)));
        }
    }
}

/// Coerces `item` to a standard `[header]` table, converting an inline table
/// (`{ ... }`) in place so a leading comment can be attached to its header.
fn as_standard_table(item: &mut Item) -> Option<&mut Table> {
    if item.is_inline_table()
        && let Some(inline) = item.as_inline_table().cloned()
    {
        *item = Item::Table(inline.into_table());
    }
    item.as_table_mut()
}

/// Renders a schema description as one or more `# ` comment lines (each ending
/// in a newline), so a multi-line description becomes multi-line comments.
fn comment_block(desc: &str) -> String {
    desc.lines()
        .map(|line| {
            if line.is_empty() {
                "#\n".to_string()
            } else {
                format!("# {line}\n")
            }
        })
        .collect()
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn generated_template_parses_to_expected_defaults() {
        let text = default_document().to_string();
        let cfg: Config = toml_edit::de::from_str(&text).unwrap();
        assert_eq!(cfg, Config::default());
        assert!(text.starts_with(&format!("#:schema {SCHEMA_URL}")));
        assert_eq!(cfg.general.default_time_range, TimeRange::All);
        assert_eq!(cfg.usage.quota.panels, default_quota_panels());
        assert!(cfg.usage.shows_quota_panel("cursor"));
        assert!(!cfg.usage.merge_models);
        assert_eq!(cfg.usage.refresh_interval, 10);
        assert_eq!(cfg.usage.quota.refresh_interval, 60);
        assert_eq!(cfg.analysis.refresh_interval, 10);
        assert_eq!(cfg.performance.scan_threads, 0);
        assert_eq!(cfg.providers, ProvidersConfig::default());
        assert!(cfg.providers.cursor);
        assert!(cfg.providers.grok);
        assert_eq!(cfg.logging.level, LogLevel::Warn);
        assert_eq!(cfg.logging.retention_days, 7);
    }

    #[test]
    fn missing_sections_use_defaults() {
        // An empty file must still default the opt-out settings, which only holds
        // because the section structs impl Default by hand.
        let cfg: Config = toml_edit::de::from_str("").unwrap();
        assert_eq!(cfg.usage.quota.panels, default_quota_panels());
        assert!(cfg.providers.cursor);
        assert!(cfg.providers.grok);
        assert_eq!(cfg.usage.refresh_secs(), 10);
        assert_eq!(cfg.usage.quota_refresh_secs(), 60);
        // A file with no [logging] section backfills the whole section default,
        // which is what keeps the additive section migration-free.
        assert_eq!(cfg.logging, LoggingConfig::default());
        assert_eq!(cfg.performance, PerformanceConfig::default());
    }

    #[test]
    fn scan_threads_resolve_config_then_env_then_auto() {
        let auto = PerformanceConfig { scan_threads: 0 };
        assert_eq!(auto.resolved_scan_threads_with(16, None), 2);
        assert_eq!(auto.resolved_scan_threads_with(1, None), 1);
        assert_eq!(auto.resolved_scan_threads_with(16, Some("7")), 7);
        assert_eq!(auto.resolved_scan_threads_with(4, Some("99")), 4);
        assert_eq!(auto.resolved_scan_threads_with(16, Some("0")), 2);
        assert_eq!(auto.resolved_scan_threads_with(16, Some("invalid")), 2);

        let configured = PerformanceConfig { scan_threads: 12 };
        assert_eq!(configured.resolved_scan_threads_with(8, Some("3")), 8);
    }

    #[test]
    fn partial_usage_section_keeps_quota_default() {
        let cfg: Config = toml_edit::de::from_str("[usage]\nmerge_models = true\n").unwrap();
        assert!(cfg.usage.merge_models);
        assert_eq!(cfg.usage.quota.panels, default_quota_panels());
        assert_eq!(cfg.usage.quota_refresh_secs(), 60);
    }

    #[test]
    fn quota_panels_can_be_narrowed_or_emptied() {
        let cfg: Config =
            toml_edit::de::from_str("[usage.quota]\npanels = [\"claude\"]\n").unwrap();
        assert!(cfg.usage.shows_quota_panel("claude"));
        assert!(!cfg.usage.shows_quota_panel("cursor"));

        let empty: Config = toml_edit::de::from_str("[usage.quota]\npanels = []\n").unwrap();
        assert!(!empty.usage.shows_quota_panel("claude"));
    }

    #[test]
    fn refresh_interval_reads_legacy_secs() {
        // Old files used `refresh_interval_secs`; the migration shim maps it.
        let text = "[usage]\nrefresh_interval_secs = 5\n[analysis]\nrefresh_interval_secs = 7\n";
        let mut cfg: Config = toml_edit::de::from_str(text).unwrap();
        migrate_legacy(&mut cfg, text);
        assert_eq!(cfg.usage.refresh_secs(), 5);
        assert_eq!(cfg.analysis.refresh_secs(), 7);
    }

    #[test]
    fn coexisting_refresh_keys_preserve_the_rest_of_the_config() {
        // A mid-upgrade file carrying BOTH the new and the legacy key must not
        // trip serde's duplicate-field error and reset the whole config to
        // defaults; parsing succeeds, the new key wins, and unrelated sections
        // survive.
        let text = "[general]\ndefault_time_range = \"weekly\"\n[usage]\nrefresh_interval = 5\nrefresh_interval_secs = 10\n[providers]\ncursor = false\n";
        let mut cfg: Config = toml_edit::de::from_str(text).unwrap();
        migrate_legacy(&mut cfg, text);
        assert_eq!(cfg.usage.refresh_secs(), 5);
        assert_eq!(cfg.general.default_time_range, TimeRange::Weekly);
        assert!(!cfg.providers.cursor);
    }

    #[test]
    fn migrates_legacy_quota_panels() {
        // Pre-`[usage.quota]` layout: quota_panels sat directly under [usage].
        let text = "[usage]\nquota_panels = [\"claude\"]\n";
        let mut cfg: Config = toml_edit::de::from_str(text).unwrap();
        migrate_legacy(&mut cfg, text);
        assert_eq!(cfg.usage.quota.panels, vec!["claude".to_string()]);
        assert!(!cfg.usage.shows_quota_panel("cursor"));
    }

    #[test]
    fn new_quota_panels_win_over_legacy() {
        let text = "[usage]\nquota_panels = [\"claude\"]\n[usage.quota]\npanels = []\n";
        let mut cfg: Config = toml_edit::de::from_str(text).unwrap();
        migrate_legacy(&mut cfg, text);
        assert!(cfg.usage.quota.panels.is_empty());
    }

    #[test]
    fn migrate_document_upgrades_a_full_legacy_file() {
        let legacy = "# old header\n\n[usage]\nmerge_models = false\nquota_panels = [\"claude\", \"codex\"]\nrefresh_interval_secs = 15\n\n[analysis]\nrefresh_interval_secs = 20\n";
        let migrated = migrate_text(legacy).unwrap().expect("legacy file changes");
        // The `#:schema` directive lands on the first line.
        assert!(migrated.starts_with("#:schema "));
        // Legacy keys are gone; the current nested layout is in place.
        assert!(!migrated.contains("quota_panels"));
        assert!(!migrated.contains("refresh_interval_secs"));
        assert!(migrated.contains("[usage.quota]"));
        // The user's names keep their order; panels that shipped later are
        // appended once, and the file is stamped so that only happens once.
        assert!(migrated.contains("panels = [\"claude\", \"codex\", \"grok\"]"));
        let cfg: Config = toml_edit::de::from_str(&migrated).unwrap();
        assert_eq!(cfg.usage.refresh_interval, 15);
        assert_eq!(cfg.analysis.refresh_interval, 20);
        assert_eq!(
            cfg.usage.quota.panels,
            vec![
                "claude".to_string(),
                "codex".to_string(),
                "grok".to_string()
            ]
        );
        assert_eq!(cfg.usage.quota.refresh_interval, 60);
        assert_eq!(cfg.general.version, CONFIG_VERSION);
    }

    #[test]
    fn migrate_document_is_idempotent() {
        let legacy = "[usage]\nquota_panels = [\"claude\"]\nrefresh_interval_secs = 15\n";
        let once = migrate_text(legacy).unwrap().expect("first pass changes");
        // A second pass over the migrated text writes nothing.
        assert!(migrate_text(&once).unwrap().is_none());
    }

    #[test]
    fn migrate_document_noops_on_the_generated_default() {
        let current = default_document().to_string();
        assert!(migrate_text(&current).unwrap().is_none());
    }

    #[test]
    fn migrate_document_adds_only_the_schema_directive_when_keys_are_current() {
        // Current key names, nested quota and version marker, but missing the
        // `#:schema` directive.
        let text = "[general]\nversion = 2\n\n[usage]\nrefresh_interval = 10\n\n[usage.quota]\npanels = [\"claude\"]\n";
        let migrated = migrate_text(text).unwrap().expect("adds #:schema");
        assert!(migrated.starts_with("#:schema "));
        assert!(migrated.contains("refresh_interval = 10"));
        assert!(migrated.contains("panels = [\"claude\"]"));
    }

    #[test]
    fn migrate_document_drops_stale_refresh_key_when_both_present() {
        let text = "#:schema x\n[usage]\nrefresh_interval = 5\nrefresh_interval_secs = 10\n";
        let migrated = migrate_text(text).unwrap().expect("drops the legacy key");
        assert!(!migrated.contains("refresh_interval_secs"));
        let cfg: Config = toml_edit::de::from_str(&migrated).unwrap();
        assert_eq!(cfg.usage.refresh_interval, 5);
    }

    #[test]
    fn migrate_document_leaves_an_inline_usage_table_to_the_read_shim() {
        // An inline `usage = { ... }` table is not restructured (only `#:schema`
        // is added), so nothing is lost trying to nest into an inline table.
        let text = "usage = { quota_panels = [\"claude\"], refresh_interval_secs = 30 }\n";
        let migrated = migrate_text(text).unwrap().expect("adds #:schema");
        assert!(migrated.starts_with("#:schema "));
        assert!(migrated.contains("quota_panels"));
        // Still idempotent for the untouched inline table.
        assert!(migrate_text(&migrated).unwrap().is_none());
    }

    #[test]
    fn migrate_text_errors_on_malformed_toml() {
        assert!(migrate_text("= not valid").is_err());
    }

    #[test]
    fn migrate_document_drops_a_malformed_legacy_refresh_value() {
        // A non-u64 legacy value must NOT be promoted into the typed field (that
        // would make serde reject the migrated file and reset every setting); it
        // is dropped so the default applies, and unrelated settings survive.
        let text = "[general]\ndefault_time_range = \"weekly\"\n[usage]\nrefresh_interval_secs = -5\n[providers]\ncursor = false\n";
        let migrated = migrate_text(text).unwrap().expect("legacy file changes");
        assert!(!migrated.contains("refresh_interval = -5"));
        assert!(!migrated.contains("refresh_interval_secs"));
        let cfg: Config = toml_edit::de::from_str(&migrated).unwrap();
        assert_eq!(cfg.general.default_time_range, TimeRange::Weekly);
        assert!(!cfg.providers.cursor);
        assert_eq!(cfg.usage.refresh_interval, 10);
        // The now-clean file is stable across further passes.
        assert!(migrate_text(&migrated).unwrap().is_none());
    }

    #[test]
    fn migrate_document_preserves_a_hand_added_comment_on_a_renamed_key() {
        let text = "[usage]\n# keep me\nrefresh_interval_secs = 15\n";
        let migrated = migrate_text(text).unwrap().expect("legacy file changes");
        assert!(migrated.contains("# keep me"));
        assert!(migrated.contains("refresh_interval = 15"));
    }

    #[test]
    fn migrate_document_adds_the_directive_despite_a_buried_schema_line() {
        // A `#:schema`-prefixed line inside a string value must not be mistaken
        // for the real leading directive and skip the prepend.
        let text = "[usage]\nquota_panels = [\"claude\"]\nnote = \"\"\"\n#:schema fake\n\"\"\"\n";
        let migrated = migrate_text(text)
            .unwrap()
            .expect("adds the real directive");
        assert!(migrated.starts_with("#:schema https://"));
    }

    #[test]
    fn migrate_document_merges_panels_into_an_existing_quota_table() {
        // Legacy quota_panels + a `[usage.quota]` that has refresh_interval but no
        // panels: panels is added and the user's refresh_interval survives.
        let text = "[usage]\nquota_panels = [\"claude\"]\n\n[usage.quota]\nrefresh_interval = 30\n";
        let migrated = migrate_text(text).unwrap().expect("legacy file changes");
        assert!(!migrated.contains("quota_panels"));
        let cfg: Config = toml_edit::de::from_str(&migrated).unwrap();
        assert_eq!(
            cfg.usage.quota.panels,
            vec!["claude".to_string(), "grok".to_string()]
        );
        assert_eq!(cfg.usage.quota.refresh_interval, 30);
        assert!(migrate_text(&migrated).unwrap().is_none());
    }

    #[test]
    fn migrate_document_drops_legacy_quota_panels_when_new_panels_present() {
        let text = "#:schema x\n[usage]\nquota_panels = [\"gemini\"]\n\n[usage.quota]\npanels = [\"claude\"]\n";
        let migrated = migrate_text(text).unwrap().expect("drops the legacy key");
        assert!(!migrated.contains("quota_panels"));
        let cfg: Config = toml_edit::de::from_str(&migrated).unwrap();
        assert_eq!(
            cfg.usage.quota.panels,
            vec!["claude".to_string(), "grok".to_string()]
        );
    }

    #[test]
    fn migrate_document_skips_an_inline_quota_child() {
        // An inline `quota = { ... }` under `[usage]` is left untouched (with its
        // legacy sibling) rather than risk losing data merging into it — and no
        // version marker is stamped, so the file is not recorded as upgraded.
        let text =
            "#:schema x\n[usage]\nquota_panels = [\"claude\"]\nquota = { panels = [\"codex\"] }\n";
        assert!(migrate_text(text).unwrap().is_none());
        assert!(panels_out_of_reach(&text.parse::<DocumentMut>().unwrap()));
    }

    /// The one-shot contract: a panel that shipped after the file was written is
    /// added once, and removing it afterwards sticks.
    #[test]
    fn backfilled_panel_is_added_once_and_stays_removed() {
        let text = "#:schema x\n[general]\ndefault_time_range = \"all\"\n\n[usage.quota]\npanels = [\"claude\", \"codex\"]\n";
        let migrated = migrate_text(text)
            .unwrap()
            .expect("version 1 file upgrades");
        assert!(migrated.contains("panels = [\"claude\", \"codex\", \"grok\"]"));
        assert!(migrated.contains("version = 2"));
        assert!(migrate_text(&migrated).unwrap().is_none());

        // The user removes it again: the marker keeps the upgrade from re-running.
        let pruned = migrated.replace(
            "[\"claude\", \"codex\", \"grok\"]",
            "[\"claude\", \"codex\"]",
        );
        assert!(migrate_text(&pruned).unwrap().is_none());
        let cfg: Config = toml_edit::de::from_str(&pruned).unwrap();
        assert!(!cfg.usage.shows_quota_panel("grok"));
    }

    /// A panel the user dropped *before* this upgrade is not resurrected: only
    /// the names a later version introduced are back-filled.
    #[test]
    fn backfill_leaves_previously_removed_panels_alone() {
        let text = "#:schema x\n[usage.quota]\npanels = [\"claude\"]\n";
        let migrated = migrate_text(text)
            .unwrap()
            .expect("version 1 file upgrades");
        let cfg: Config = toml_edit::de::from_str(&migrated).unwrap();
        assert_eq!(
            cfg.usage.quota.panels,
            vec!["claude".to_string(), "grok".to_string()],
            "codex / copilot / cursor were removed on purpose and stay removed"
        );
    }

    #[test]
    fn backfill_never_reopens_a_band_turned_off() {
        // `panels = []` hides the whole band; the upgrade must not undo that.
        let text = "#:schema x\n[usage.quota]\npanels = []\n";
        let migrated = migrate_text(text).unwrap().expect("the marker is stamped");
        let cfg: Config = toml_edit::de::from_str(&migrated).unwrap();
        assert!(cfg.usage.quota.panels.is_empty());
        assert_eq!(cfg.general.version, CONFIG_VERSION);
    }

    #[test]
    fn backfill_stamps_a_file_with_no_general_section() {
        // A hand-written file may have no `[general]` at all; the marker still
        // needs somewhere to live, and the result must stay valid TOML.
        let text = "#:schema x\n[providers]\ncursor = false\n";
        let migrated = migrate_text(text).unwrap().expect("the marker is stamped");
        let cfg: Config = toml_edit::de::from_str(&migrated).unwrap();
        assert_eq!(cfg.general.version, CONFIG_VERSION);
        assert!(!cfg.providers.cursor);
        // An absent panel list simply picks up the current default.
        assert!(cfg.usage.shows_quota_panel("grok"));
        assert!(migrate_text(&migrated).unwrap().is_none());
    }

    #[test]
    fn an_empty_file_reaches_the_current_layout_in_one_pass() {
        // The back-fill creates `[general]` on a file that had no tables at all,
        // so the `#:schema` directive has to be attached after it — otherwise
        // the first pass writes a file the second pass rewrites again.
        for text in ["", "# just a comment\n"] {
            let migrated = migrate_text(text)
                .unwrap()
                .expect("an empty file is stamped");
            assert!(migrated.starts_with("#:schema "));
            assert!(migrated.contains("version = 2"));
            assert!(
                migrate_text(&migrated).unwrap().is_none(),
                "one pass must be enough"
            );
        }
    }

    #[test]
    fn a_panel_list_that_could_not_be_moved_is_not_marked_upgraded() {
        // `migrate_quota_panels` refuses to merge into an inline `quota` child,
        // so the legacy list survives out of reach. Stamping the marker here
        // would retire the one-shot upgrade without ever having run it.
        let text =
            "#:schema x\n[usage]\nquota_panels = [\"claude\"]\nquota = { refresh_interval = 30 }\n";
        assert!(migrate_text(text).unwrap().is_none());
        assert!(panels_out_of_reach(&text.parse::<DocumentMut>().unwrap()));
    }

    #[test]
    fn a_hand_edited_version_value_never_resets_the_config() {
        // A non-integer marker must read as legacy, not fail the document: the
        // infallible read would turn that into a silent reset of every setting.
        for bad in ["\"2\"", "2.5", "true", "-1"] {
            let text = format!(
                "[general]\nversion = {bad}\ndefault_time_range = \"weekly\"\n[providers]\ncursor = false\n"
            );
            let cfg: Config = toml_edit::de::from_str(&text).expect("document still parses");
            assert_eq!(cfg.general.version, legacy_config_version(), "bad = {bad}");
            assert_eq!(cfg.general.default_time_range, TimeRange::Weekly);
            assert!(!cfg.providers.cursor);
            // Being read as legacy, the upgrade pass rewrites it with a real one.
            let migrated = migrate_text(&text)
                .unwrap()
                .expect("the marker is repaired");
            let cfg: Config = toml_edit::de::from_str(&migrated).unwrap();
            assert_eq!(cfg.general.version, CONFIG_VERSION);
        }
    }

    #[test]
    fn every_backfilled_panel_ships_by_the_current_version() {
        for (version, name) in PANELS_ADDED_BY_VERSION {
            assert!(
                *version <= CONFIG_VERSION,
                "{name} is scheduled for a version this build never stamps"
            );
            assert!(
                default_quota_panels().iter().any(|p| p == name),
                "{name} is back-filled but is not a current default panel"
            );
        }
    }

    #[test]
    fn refresh_secs_clamps_zero_to_one() {
        let cfg = UsageConfig {
            refresh_interval: 0,
            quota: QuotaConfig {
                refresh_interval: 0,
                ..QuotaConfig::default()
            },
            ..UsageConfig::default()
        };
        assert_eq!(cfg.refresh_secs(), 1);
        assert_eq!(cfg.quota_refresh_secs(), 1);
    }

    #[test]
    fn providers_default_all_enabled() {
        let p = ProvidersConfig::default();
        assert!(
            p.claude
                && p.codex
                && p.copilot
                && p.gemini
                && p.opencode
                && p.cursor
                && p.hermes
                && p.grok
        );
    }

    #[test]
    fn committed_schema_matches_generated() {
        // Guards `vct.schema.json` against drift from the typed Config.
        // Regenerate with: `vct config schema > vct.schema.json`.
        let path = concat!(env!("CARGO_MANIFEST_DIR"), "/../../vct.schema.json");
        let committed: Value =
            serde_json::from_str(&std::fs::read_to_string(path).expect("vct.schema.json exists"))
                .expect("vct.schema.json is valid JSON");
        assert_eq!(committed, json_schema());
    }
}