lash-tool-support 0.1.0-alpha.42

use lash_core::ToolResult;
use std::io::{BufRead, BufReader};
use std::path::{Component, Path, PathBuf};
use std::time::{SystemTime, UNIX_EPOCH};

mod static_provider;
pub use static_provider::{StaticToolExecute, StaticToolProvider};

/// Resolve a possibly-relative `path` against `base`, returning a lexically
/// normalized [`PathBuf`].
///
/// Behavior:
/// - Absolute `path` passes through unchanged (only normalized).
/// - Relative `path` is joined onto `base`.
/// - `.` and `..` components are collapsed *lexically* — purely by string
///   manipulation, without touching the filesystem and without requiring the
///   path (or its parents) to exist.
///
/// Lexical (rather than `std::fs::canonicalize`) resolution is the deliberate
/// choice for tool path handling: write/patch tools must resolve targets that
/// do not yet exist on disk, and canonicalization both fails for missing paths
/// and silently rewrites symlinks. Tools that genuinely need symlink-real-path
/// resolution for an existence/scope check should use [`canonicalize_under`]
/// instead and accept that it requires the path to exist.
pub fn resolve_under(base: &Path, path: &Path) -> PathBuf {
    let joined = if path.is_absolute() {
        path.to_path_buf()
    } else {
        base.join(path)
    };
    normalize_lexical(&joined)
}

/// Lexically collapse `.` and `..` components in `path` without touching the
/// filesystem. Leading `..` components (that would escape the root) are
/// preserved verbatim, matching `Path::join` intuitions for relative roots.
pub fn normalize_lexical(path: &Path) -> PathBuf {
    let mut normalized = PathBuf::new();
    for component in path.components() {
        match component {
            Component::CurDir => {}
            Component::ParentDir => {
                if !normalized.pop() {
                    normalized.push(component.as_os_str());
                }
            }
            Component::Prefix(_) | Component::RootDir | Component::Normal(_) => {
                normalized.push(component.as_os_str());
            }
        }
    }
    normalized
}

/// Resolve `path` against `base` (via [`resolve_under`]) and then canonicalize
/// it on disk, resolving symlinks to their real path. Fails if the path does
/// not exist. Use this only when a tool needs a real, existence-checked path
/// (e.g. a security/scope decision or distinguishing a file from a directory);
/// prefer [`resolve_under`] for write/patch targets that may not exist yet.
pub fn canonicalize_under(base: &Path, path: &Path) -> std::io::Result<PathBuf> {
    std::fs::canonicalize(resolve_under(base, path))
}

/// Render `path` relative to `base` for display, falling back to the file name
/// (then the full path) when `path` is not under `base`. Backslashes are
/// normalized to forward slashes so output is stable across platforms.
pub fn display_relative(base: &Path, path: &Path) -> String {
    let display = path
        .strip_prefix(base)
        .unwrap_or(path)
        .display()
        .to_string();
    let display = if display.is_empty() {
        path.file_name()
            .and_then(|name| name.to_str())
            .unwrap_or(".")
            .to_string()
    } else {
        display
    };
    display.replace('\\', "/")
}

/// Shared preamble describing default filesystem-listing behavior.
/// Used by `ls` and `glob` so both tools document hidden-file and
/// `.gitignore` handling in identical wording.
pub const FS_DEFAULTS_PREAMBLE: &str =
    "By default this includes hidden files and respects `.gitignore` only inside Git repos.";

#[derive(Clone, Debug, serde::Serialize)]
pub struct PathEntry {
    pub path: String,
    pub kind: String,
    pub size_bytes: u64,
    pub lines: Option<u64>,
    pub modified_at: String,
}

#[derive(Clone, Debug, serde::Serialize)]
pub struct TruncationMeta {
    pub shown: usize,
    pub total: usize,
    pub omitted: usize,
}

/// Extract a required non-empty string arg, or return ToolResult::err.
pub fn require_str<'a>(args: &'a serde_json::Value, key: &str) -> Result<&'a str, ToolResult> {
    args.get(key)
        .and_then(|v| v.as_str())
        .filter(|s| !s.is_empty())
        .ok_or_else(|| ToolResult::err_fmt(format_args!("Missing required parameter: {key}")))
}

/// Parse optional bool arg with a default.
pub fn parse_optional_bool(
    args: &serde_json::Value,
    key: &str,
    default: bool,
) -> Result<bool, ToolResult> {
    match args.get(key) {
        None => Ok(default),
        Some(v) if v.is_null() => Ok(default),
        Some(v) => match v.as_bool() {
            Some(b) => Ok(b),
            None => Err(ToolResult::err_fmt(format_args!(
                "Invalid {key}: expected bool"
            ))),
        },
    }
}

/// Parse an optional positive integer arg.
/// Accepts `null` or `"none"` when `allow_none` is true.
pub fn parse_optional_usize_arg(
    args: &serde_json::Value,
    key: &str,
    default: Option<usize>,
    allow_none: bool,
    min: usize,
) -> Result<Option<usize>, ToolResult> {
    match args.get(key) {
        None => Ok(default),
        Some(v) if v.is_null() => {
            if allow_none {
                Ok(None)
            } else {
                Err(ToolResult::err_fmt(format_args!(
                    "Invalid {key}: expected int >= {min}"
                )))
            }
        }
        Some(v) => {
            if let Some(s) = v.as_str() {
                if allow_none && s.eq_ignore_ascii_case("none") {
                    return Ok(None);
                }
                return Err(ToolResult::err_fmt(format_args!(
                    "Invalid {key}: expected int{}",
                    if allow_none {
                        ", null, or \"none\""
                    } else {
                        ""
                    }
                )));
            }
            let n = v.as_u64().ok_or_else(|| {
                ToolResult::err_fmt(format_args!(
                    "Invalid {key}: expected int{}",
                    if allow_none {
                        ", null, or \"none\""
                    } else {
                        ""
                    }
                ))
            })? as usize;
            if n < min {
                return Err(ToolResult::err_fmt(format_args!(
                    "Invalid {key}: must be >= {min}{}",
                    if allow_none {
                        ", or use null/\"none\" for no cap"
                    } else {
                        ""
                    }
                )));
            }
            Ok(Some(n))
        }
    }
}

pub fn object_schema(properties: serde_json::Value, required: &[&str]) -> serde_json::Value {
    serde_json::json!({
        "type": "object",
        "properties": properties,
        "required": required,
        "additionalProperties": false,
    })
}

pub fn path_entry_output_schema() -> serde_json::Value {
    serde_json::json!({
        "type": "object",
        "properties": {
            "path": { "type": "string" },
            "kind": { "type": "string", "enum": ["file", "dir", "symlink", "other"] },
            "size_bytes": { "type": "integer", "minimum": 0 },
            "lines": {
                "anyOf": [
                    { "type": "integer", "minimum": 0 },
                    { "type": "null" }
                ]
            },
            "modified_at": {
                "type": "string",
                "description": "Modification timestamp formatted as RFC3339 UTC."
            }
        },
        "required": ["path", "kind", "size_bytes", "lines", "modified_at"],
        "additionalProperties": false,
    })
}

pub fn filesystem_entries_output_schema() -> serde_json::Value {
    serde_json::json!({
        "type": "object",
        "properties": {
            "items": {
                "type": "array",
                "items": path_entry_output_schema()
            },
            "truncated": {
                "anyOf": [
                    {
                        "type": "object",
                        "properties": {
                            "shown": { "type": "integer", "minimum": 0 },
                            "total": { "type": "integer", "minimum": 0 },
                            "omitted": { "type": "integer", "minimum": 0 }
                        },
                        "required": ["shown", "total", "omitted"],
                        "additionalProperties": false
                    },
                    { "type": "null" }
                ]
            }
        },
        "required": ["items", "truncated"],
        "additionalProperties": false,
    })
}

pub fn agent_surface(
    module_path: impl IntoIterator<Item = impl Into<String>>,
    operation: impl Into<String>,
    aliases: &[&str],
) -> lash_core::ToolAgentSurface {
    lash_core::ToolAgentSurface::new(module_path, operation).with_aliases(aliases.iter().copied())
}

/// Run blocking filesystem work off the async runtime.
pub async fn run_blocking<F>(f: F) -> ToolResult
where
    F: FnOnce() -> ToolResult + Send + 'static,
{
    match tokio::task::spawn_blocking(f).await {
        Ok(result) => result,
        Err(e) => ToolResult::err_fmt(format_args!("blocking task failed: {e}")),
    }
}

/// Run blocking work off the async runtime and return a typed value.
pub async fn run_blocking_value<F, T>(f: F) -> Result<T, String>
where
    F: FnOnce() -> T + Send + 'static,
    T: Send + 'static,
{
    tokio::task::spawn_blocking(f)
        .await
        .map_err(|err| format!("blocking task failed: {err}"))
}

/// Build a normalized filesystem entry for tool output.
/// Returns the entry plus raw mtime for optional sorting.
pub fn build_path_entry(path: &Path, with_lines: bool) -> (PathEntry, SystemTime) {
    let fallback_mtime = UNIX_EPOCH;
    let path_str = path.to_string_lossy().to_string();

    let metadata = match std::fs::symlink_metadata(path) {
        Ok(m) => m,
        Err(_) => {
            let entry = PathEntry {
                path: path_str,
                kind: "other".to_string(),
                size_bytes: 0,
                lines: None,
                modified_at: format_time_rfc3339(fallback_mtime),
            };
            return (entry, fallback_mtime);
        }
    };

    let file_type = metadata.file_type();
    let kind = if file_type.is_symlink() {
        "symlink"
    } else if file_type.is_dir() {
        "dir"
    } else if file_type.is_file() {
        "file"
    } else {
        "other"
    };

    let mtime = metadata.modified().unwrap_or(fallback_mtime);
    let lines = if with_lines && kind == "file" {
        count_text_lines(path)
    } else {
        None
    };

    let entry = PathEntry {
        path: path_str,
        kind: kind.to_string(),
        size_bytes: metadata.len(),
        lines,
        modified_at: format_time_rfc3339(mtime),
    };
    (entry, mtime)
}

pub fn rg_file_list(
    base: &Path,
    include_hidden: bool,
    respect_gitignore: bool,
    max_depth: Option<usize>,
    globs: &[String],
) -> Result<Vec<PathBuf>, ToolResult> {
    let mut builder = ignore::WalkBuilder::new(base);
    builder.hidden(!include_hidden).max_depth(max_depth);

    if respect_gitignore {
        builder.git_ignore(true).git_exclude(true).git_global(true);
        builder.require_git(true);
    } else {
        builder
            .git_ignore(false)
            .git_exclude(false)
            .git_global(false)
            .ignore(false)
            .parents(false)
            .require_git(false);
    }

    if !globs.is_empty() {
        let mut override_builder = ignore::overrides::OverrideBuilder::new(base);
        for glob in globs {
            override_builder.add(glob).map_err(|err| {
                ToolResult::err_fmt(format_args!(
                    "invalid ignore glob for {}: {err}",
                    base.display()
                ))
            })?;
        }

        let overrides = override_builder.build().map_err(|err| {
            ToolResult::err_fmt(format_args!(
                "failed to build ignore globs for {}: {err}",
                base.display()
            ))
        })?;
        builder.overrides(overrides);
    }

    let files = builder
        .build()
        .filter_map(Result::ok)
        .filter(|entry| entry.path() != base)
        .map(ignore::DirEntry::into_path)
        .collect();
    Ok(files)
}

/// Build the standard result envelope returned by filesystem listing tools.
pub fn filesystem_entries_result(items: Vec<PathEntry>, total_count: usize) -> serde_json::Value {
    let shown = items.len();
    let truncated = if total_count > shown {
        Some(TruncationMeta {
            shown,
            total: total_count,
            omitted: total_count - shown,
        })
    } else {
        None
    };
    serde_json::json!({
        "items": items,
        "truncated": truncated,
    })
}

fn count_text_lines(path: &Path) -> Option<u64> {
    let file = std::fs::File::open(path).ok()?;
    let reader = BufReader::new(file);
    let mut count = 0_u64;
    for line in reader.lines() {
        if line.is_err() {
            return None;
        }
        count += 1;
    }
    Some(count)
}

fn format_time_rfc3339(ts: SystemTime) -> String {
    chrono::DateTime::<chrono::Utc>::from(ts).to_rfc3339_opts(chrono::SecondsFormat::Secs, true)
}

/// Generate a compact unified diff between old and new content.
/// Truncates to `max_lines` lines if the diff is too long.
pub fn compact_diff(old: &str, new: &str, path: &str, max_lines: usize) -> String {
    let diff = similar::TextDiff::from_lines(old, new);
    let unified = diff
        .unified_diff()
        .header(&format!("a/{path}"), &format!("b/{path}"))
        .to_string();
    if unified.is_empty() {
        return String::new();
    }
    let lines: Vec<&str> = unified.lines().collect();
    if lines.len() <= max_lines {
        unified
    } else {
        let mut truncated: String = lines[..max_lines].join("\n");
        truncated.push_str(&format!("\n... ({} more lines)", lines.len() - max_lines));
        truncated
    }
}