tokenix 0.22.1

use anyhow::Result;
use serde::Deserialize;
use std::path::{Path, PathBuf};
use std::time::{SystemTime, UNIX_EPOCH};

use crate::chunker::count_tokens;
use crate::query::{format_results, get_file_outline, query_index};
use crate::store::{index_staleness, log_hook_event, search_by_symbol, HookEvent};

const MIN_LINES_FOR_OUTLINE: usize = 200;
const MIN_QUERY_WORDS: usize = 3;

/// Normalized hook input used by tokenix.
///
/// Claude Code sends `tool_name` and `tool_input` on stdin.
/// GitHub Copilot hooks currently send `toolName` and `toolArgs` on stdin.
/// Older Copilot-like runners may set TOOL_NAME/TOOL_INPUT environment vars.
#[derive(Deserialize, Debug, Default)]
pub struct HookInput {
    #[serde(default)]
    pub tool_name: String,
    #[serde(default)]
    pub tool_input: serde_json::Value,
}

#[derive(Deserialize, Debug)]
struct CopilotHookInput {
    #[serde(rename = "toolName")]
    tool_name: String,
    #[serde(rename = "toolArgs", default)]
    tool_args: serde_json::Value,
}

impl HookInput {
    fn from_env() -> Option<Self> {
        // Env vars are a fallback for non-standard tools; Copilot uses stdin.
        // Only support generic TOOL_NAME/TOOL_INPUT (not COPILOT_* which can't normalize).
        let tool_name = std::env::var("TOOL_NAME").ok()?;
        let tool_input_raw = std::env::var("TOOL_INPUT").unwrap_or_default();
        let tool_input = serde_json::from_str(&tool_input_raw).unwrap_or(serde_json::Value::Null);
        Some(HookInput {
            tool_name,
            tool_input,
        })
    }

    fn from_stdin(raw: &str) -> Option<Self> {
        let clean = raw.trim_start_matches('\u{feff}').trim();
        if clean.is_empty() {
            return None;
        }
        if let Ok(input) = serde_json::from_str::<HookInput>(clean) {
            if !input.tool_name.is_empty() {
                // Canonicalize here too: newer Copilot/Codex builds send the snake_case
                // `tool_name`/`tool_input` shape with harness names like "view", which
                // must still map to Read/Grep (and `path` -> `file_path`) or the tool
                // is never recognized and interception is silently skipped.
                let tool_name = canonical_tool_name(&input.tool_name);
                let tool_input = if tool_name == "Read" {
                    normalize_read_args(input.tool_input)
                } else {
                    input.tool_input
                };
                return Some(HookInput {
                    tool_name,
                    tool_input,
                });
            }
        }
        serde_json::from_str::<CopilotHookInput>(clean)
            .ok()
            .map(|input| normalize_copilot_input(&input.tool_name, &input.tool_args))
    }
}

/// Map a harness-specific tool name to tokenix's canonical name.
///
/// Claude Code already sends `Read`/`Grep`/`Bash`; GitHub Copilot (and some Codex
/// builds) send `view`/`read`/`grep` in either the legacy `toolName` field or the
/// newer snake_case `tool_name` field. Canonicalizing in one place means
/// interception no longer depends on which field shape or casing a harness uses.
/// Unrecognized names (Bash variants, Edit, etc.) pass through unchanged.
fn canonical_tool_name(name: &str) -> String {
    match name.to_ascii_lowercase().as_str() {
        "read" | "view" => "Read".to_string(),
        "grep" => "Grep".to_string(),
        _ => name.to_string(),
    }
}

fn normalize_copilot_input(tool_name: &str, tool_args: &serde_json::Value) -> HookInput {
    let args = if let Some(raw) = tool_args.as_str() {
        serde_json::from_str(raw).unwrap_or(serde_json::Value::Null)
    } else {
        tool_args.clone()
    };

    let tool_name = canonical_tool_name(tool_name);
    let tool_input = if tool_name == "Read" {
        normalize_read_args(args)
    } else {
        args
    };
    HookInput {
        tool_name,
        tool_input,
    }
}

fn normalize_read_args(mut args: serde_json::Value) -> serde_json::Value {
    if args.get("file_path").and_then(|v| v.as_str()).is_some() {
        return args;
    }

    let path = args
        .get("path")
        .or_else(|| args.get("file"))
        .and_then(|v| v.as_str())
        .map(str::to_string);

    if let Some(path) = path {
        if let Some(obj) = args.as_object_mut() {
            obj.insert("file_path".to_string(), serde_json::Value::String(path));
        }
    }
    args
}

fn find_repo_root() -> PathBuf {
    let cwd = std::env::current_dir().unwrap_or_else(|_| PathBuf::from("."));
    crate::store::find_project_root(&cwd)
}

fn now_ts() -> f64 {
    SystemTime::now()
        .duration_since(UNIX_EPOCH)
        .unwrap()
        .as_secs_f64()
}

fn is_semantic_query(pattern: &str) -> bool {
    pattern.split_whitespace().count() >= MIN_QUERY_WORDS
}

/// True if `s` looks like a plain identifier (no regex metacharacters).
fn looks_like_identifier(s: &str) -> bool {
    s.len() >= 2
        && s.chars()
            .all(|c| c.is_alphanumeric() || matches!(c, '_' | ':' | '.'))
}

fn symbol_lookup(pattern: &str, repo_root: &Path) -> Option<String> {
    let conn = crate::store::open_db(repo_root, false).ok()??;
    let matches = search_by_symbol(&conn, pattern).ok()?;
    if matches.is_empty() {
        return None;
    }
    let mut lines = vec![format!(
        "<!-- tokenix: {} symbol match(es) for '{}' -->",
        matches.len(),
        pattern
    )];
    lines.push(String::new());
    for m in &matches {
        lines.push(format!(
            "{}:{} [{}] {}",
            m.path, m.start_line, m.kind, m.symbol
        ));
    }
    lines.push(String::new());
    lines.push(format!(
        "[Use Read with offset/limit or tokenix read --symbol {} to see content]",
        pattern
    ));
    Some(lines.join("\n"))
}

fn handle_read(tool_input: &serde_json::Value, repo_root: &Path) -> (bool, String, String) {
    let file_path = match tool_input["file_path"].as_str() {
        Some(p) => p,
        None => return (false, String::new(), "missing file_path".to_string()),
    };

    // Let targeted reads through (offset or limit already specified)
    if !tool_input["offset"].is_null() || !tool_input["limit"].is_null() {
        return (
            false,
            String::new(),
            "targeted read (offset/limit specified)".to_string(),
        );
    }

    let full_path = {
        let p = Path::new(file_path);
        if p.exists() {
            p.to_path_buf()
        } else {
            repo_root.join(file_path)
        }
    };

    if !full_path.exists() {
        return (
            false,
            String::new(),
            format!("file not found: {}", file_path),
        );
    }

    let content = match std::fs::read_to_string(&full_path) {
        Ok(c) => c,
        Err(_) => return (false, String::new(), format!("read error: {}", file_path)),
    };

    let line_count = content.lines().count();
    if line_count < MIN_LINES_FOR_OUTLINE {
        return (
            false,
            String::new(),
            format!(
                "small file ({} < {} lines)",
                line_count, MIN_LINES_FOR_OUTLINE
            ),
        );
    }

    let outline = match get_file_outline(&full_path) {
        Some(o) => o,
        None => {
            return (
                false,
                String::new(),
                "failed to generate outline".to_string(),
            )
        }
    };

    let rel = full_path
        .strip_prefix(repo_root)
        .unwrap_or(&full_path)
        .to_string_lossy()
        .replace('\\', "/");

    let ext = full_path.extension().and_then(|e| e.to_str()).unwrap_or("");
    let is_code = matches!(
        ext,
        "rs" | "py" | "ts" | "tsx" | "js" | "jsx" | "mjs" | "cjs" | "go"
    );

    if !is_code {
        return (
            false,
            String::new(),
            format!("unsupported language: .{}", ext),
        );
    }

    let msg = format!(
        "{}\n\n[tokenix] File has {} lines. Showing symbol outline above.\n\
        To read a specific symbol: tokenix read {} --symbol <name>\n\
        To read specific lines:   use Read with offset/limit parameters.",
        outline, line_count, rel
    );
    (true, msg, "generated symbol outline".to_string())
}

/// Returns a path to use as a soft lock file for concurrent embed protection.
fn embed_lock_path() -> Option<std::path::PathBuf> {
    Some(dirs::cache_dir()?.join("tokenix").join("embed.lock"))
}

/// Best-effort concurrency guard for the ONNX embed call.
///
/// The fastembed model uses ~293 MB per process (130 MB model + ORT runtime).
/// If Claude Code fires parallel Grep hooks, each would load a separate model instance.
/// This guard makes concurrent semantic Greps fall through (exit 0) so the original
/// grep runs instead — limiting peak tokenix memory to one model instance at a time.
///
/// Implementation: timestamp file. Not atomically safe, but good enough for the
/// typical pattern of a few concurrent hooks per second. Stale locks (>30s) are
/// automatically overridden so a crashed process never permanently blocks the feature.
fn try_acquire_embed_slot() -> bool {
    let path = match embed_lock_path() {
        Some(p) => p,
        None => return true, // can't determine path → proceed anyway
    };

    if path.exists() {
        let stale = std::fs::metadata(&path)
            .ok()
            .and_then(|m| m.modified().ok())
            .and_then(|t| t.elapsed().ok())
            .map(|e| e.as_secs() >= 30)
            .unwrap_or(true);

        if !stale {
            return false; // another embed is in progress
        }
    }

    // Claim the slot (best-effort write — race window is tiny)
    let _ = std::fs::create_dir_all(path.parent().unwrap_or(&path));
    let _ = std::fs::write(&path, std::process::id().to_string());
    true
}

fn release_embed_slot() {
    if let Some(path) = embed_lock_path() {
        let _ = std::fs::remove_file(path);
    }
}

fn handle_grep(tool_input: &serde_json::Value, repo_root: &Path) -> (bool, String, String) {
    let pattern = match tool_input["pattern"].as_str() {
        Some(p) => p,
        None => return (false, String::new(), "missing pattern".to_string()),
    };

    // Short identifier-like patterns: try index symbol lookup before falling through
    if !is_semantic_query(pattern) {
        if looks_like_identifier(pattern) {
            if let Some(output) = symbol_lookup(pattern, repo_root) {
                return (
                    true,
                    output,
                    format!("matched symbol exact lookup: {}", pattern),
                );
            }
        }
        return (
            false,
            String::new(),
            format!("lexical query: '{}'", pattern),
        );
    }

    // Try daemon first: model stays resident, ~30ms vs ~430ms cold embed.
    if let Some(output) =
        crate::daemon::daemon_search_with_autostart(repo_root, pattern, 20, 2500, None)
    {
        return (true, output, "semantic search via daemon".to_string());
    }

    // Fallback: direct embed (daemon not running or failed to start).
    // Guard prevents N×293MB spikes from parallel hook processes.
    if !try_acquire_embed_slot() {
        return (
            false,
            String::new(),
            "ONNX embed model slot locked".to_string(),
        );
    }
    let results = match query_index(repo_root, pattern, 2500, 20, None) {
        Ok(Some(r)) if !r.is_empty() => r,
        _ => {
            release_embed_slot();
            return (
                false,
                String::new(),
                "semantic search returned empty results".to_string(),
            );
        }
    };
    release_embed_slot();
    (
        true,
        format_results(&results, pattern),
        "semantic search via in-process embed".to_string(),
    )
}

fn estimate_original_tokens(
    tool_name: &str,
    tool_input: &serde_json::Value,
    repo_root: &Path,
) -> i64 {
    if tool_name == "Read" {
        if let Some(fp) = tool_input["file_path"].as_str() {
            let p = Path::new(fp);
            let full = if p.exists() {
                p.to_path_buf()
            } else {
                repo_root.join(fp)
            };
            if let Ok(content) = std::fs::read_to_string(&full) {
                return count_tokens(&content) as i64;
            }
        }
    }
    800
}

/// Build the PreToolUse JSON output that rewrites a Bash command's input.
/// `hookEventName` is required by Claude Code or the whole `hookSpecificOutput`
/// is ignored and the rewrite silently does not apply.
fn bash_rewrite_output(rewritten: &str, reason: &str) -> serde_json::Value {
    serde_json::json!({
        "hookSpecificOutput": {
            "hookEventName": "PreToolUse",
            "permissionDecision": "allow",
            "permissionDecisionReason": reason,
            "updatedInput": {
                "command": rewritten,
                "CommandLine": rewritten,
                "commandLine": rewritten,
                "command_line": rewritten,
            }
        }
    })
}

fn is_bash_tool(name: &str) -> bool {
    let lower = name.to_ascii_lowercase();
    matches!(
        lower.as_str(),
        "bash"
            | "powershell"
            | "shell"
            | "run_shell_command"
            | "default_api:run_shell_command"
            | "run_command"
            | "default_api:run_command"
    )
}

pub fn run_hook() -> Result<()> {
    // Read input: prefer env vars (Copilot), fall back to stdin (Claude Code / Codex)
    let raw_stdin = std::io::read_to_string(std::io::stdin()).unwrap_or_default();

    let input = HookInput::from_env()
        .or_else(|| HookInput::from_stdin(&raw_stdin))
        .unwrap_or_default();

    // Unknown or unsupported tool: pass through silently.
    let is_bash = is_bash_tool(&input.tool_name);
    if input.tool_name != "Read" && input.tool_name != "Grep" && !is_bash {
        std::process::exit(0);
    }

    let repo_root = find_repo_root();

    if is_bash {
        let command = input.tool_input["command"]
            .as_str()
            .or_else(|| input.tool_input["CommandLine"].as_str())
            .or_else(|| input.tool_input["commandLine"].as_str())
            .or_else(|| input.tool_input["command_line"].as_str())
            .unwrap_or("")
            .trim();

        if command.is_empty() {
            std::process::exit(0);
        }

        // Avoid infinite recursion: do not rewrite if it's already a tokenix command execution
        if command.contains("tokenix") {
            std::process::exit(0);
        }

        // 1. Optimize git status -> git status --short. Let it pass through natively
        // on the second pass when the short flag is already present.
        let is_short_git_status = (command.starts_with("git status")
            || command.starts_with("git  status"))
            && (command.contains("-s") || command.contains("--short"));
        if is_short_git_status {
            std::process::exit(0);
        }

        let status_re = regex::Regex::new(r"^git\s+status(\s+.*)?$").unwrap();
        if status_re.is_match(command) && !command.contains("-") {
            let trimmed = command.strip_prefix("git status").unwrap_or("").trim();
            let rewritten = if trimmed.is_empty() {
                "git status --short".to_string()
            } else {
                format!("git status --short {}", trimmed)
            };

            let out = bash_rewrite_output(
                &rewritten,
                "rewrite git status to git status --short for token efficiency",
            );

            let _ = log_hook_event(
                &repo_root,
                &HookEvent {
                    ts: now_ts(),
                    tool: "Bash".to_string(),
                    action: "intercepted".to_string(),
                    phase: "pre".to_string(),
                    reason: "rewrote git status to git status --short".to_string(),
                    saved_tokens: 0,
                    actual_tokens: 0,
                    original_estimate: 0,
                    input_preview: command.chars().take(200).collect(),
                    command: command.to_string(),
                },
            );

            println!("{}", serde_json::to_string(&out).unwrap_or_default());
            std::process::exit(0);
        }

        // 2. Otherwise check for other active filters to wrap in tokenix run
        let filters = crate::filters::load_all_filters();
        let unwrapped =
            crate::filters::unwrap_shell_runner(command).unwrap_or_else(|| command.to_string());

        if crate::filters::find_filter(&unwrapped, &filters).is_some() {
            let exe_path = std::env::current_exe()
                .map(|p| p.to_string_lossy().replace('\\', "/"))
                .unwrap_or_else(|_| "tokenix".to_string());

            let rewritten = format!("{} run {:?}", exe_path, command);

            let out = bash_rewrite_output(&rewritten, "wrapped in tokenix compression run");

            let _ = log_hook_event(
                &repo_root,
                &HookEvent {
                    ts: now_ts(),
                    tool: "Bash".to_string(),
                    action: "intercepted".to_string(),
                    phase: "pre".to_string(),
                    reason: "rewrote command to tokenix run".to_string(),
                    saved_tokens: 0,
                    actual_tokens: 0,
                    original_estimate: 0,
                    input_preview: command.chars().take(200).collect(),
                    command: command.to_string(),
                },
            );

            println!("{}", serde_json::to_string(&out).unwrap_or_default());
            std::process::exit(0);
        }

        std::process::exit(0);
    }

    let staleness = index_staleness(&repo_root);

    if staleness.stale {
        let _ = log_hook_event(
            &repo_root,
            &HookEvent {
                ts: now_ts(),
                tool: input.tool_name,
                action: "pass".to_string(),
                phase: "pre".to_string(),
                reason: staleness.reason,
                saved_tokens: 0,
                actual_tokens: 0,
                original_estimate: 0,
                input_preview: String::new(),
                command: String::new(),
            },
        );
        std::process::exit(0);
    }

    let (intercepted, output, reason) = match input.tool_name.as_str() {
        "Read" => handle_read(&input.tool_input, &repo_root),
        "Grep" => handle_grep(&input.tool_input, &repo_root),
        _ => (false, String::new(), "unsupported tool".to_string()),
    };

    if !intercepted {
        let _ = log_hook_event(
            &repo_root,
            &HookEvent {
                ts: now_ts(),
                tool: input.tool_name,
                action: "pass".to_string(),
                phase: "pre".to_string(),
                reason,
                saved_tokens: 0,
                actual_tokens: 0,
                original_estimate: 0,
                input_preview: String::new(),
                command: String::new(),
            },
        );
        std::process::exit(0);
    }

    let original_tokens = estimate_original_tokens(&input.tool_name, &input.tool_input, &repo_root);
    let actual_tokens = count_tokens(&output) as i64;
    let saved = (original_tokens - actual_tokens).max(0);

    let _ = log_hook_event(
        &repo_root,
        &HookEvent {
            ts: now_ts(),
            tool: input.tool_name.clone(),
            action: "intercepted".to_string(),
            phase: "pre".to_string(),
            reason,
            saved_tokens: saved,
            actual_tokens,
            original_estimate: original_tokens,
            input_preview: raw_stdin.chars().take(200).collect(),
            command: String::new(),
        },
    );

    eprintln!("{}", output);
    std::process::exit(2);
}

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

    #[test]
    fn parses_claude_input() {
        let raw = r#"{"tool_name":"Read","tool_input":{"file_path":"src/main.rs"}}"#;
        let input = HookInput::from_stdin(raw).unwrap();
        assert_eq!(input.tool_name, "Read");
        assert_eq!(input.tool_input["file_path"], "src/main.rs");
    }

    #[test]
    fn parses_copilot_view_input() {
        let raw = r#"{"toolName":"view","toolArgs":"{\"path\":\"src/main.rs\"}"}"#;
        let input = HookInput::from_stdin(raw).unwrap();
        assert_eq!(input.tool_name, "Read");
        assert_eq!(input.tool_input["file_path"], "src/main.rs");
    }

    #[test]
    fn empty_stdin_returns_none() {
        assert!(HookInput::from_stdin("").is_none());
        assert!(HookInput::from_stdin("   ").is_none());
    }

    #[test]
    fn bom_prefix_stripped() {
        let raw =
            "\u{feff}{\"tool_name\":\"Grep\",\"tool_input\":{\"pattern\":\"how does auth work\"}}";
        let input = HookInput::from_stdin(raw).unwrap();
        assert_eq!(input.tool_name, "Grep");
    }

    #[test]
    fn unknown_tool_parses_as_is() {
        let raw = r#"{"tool_name":"Edit","tool_input":{"file_path":"x.rs"}}"#;
        let input = HookInput::from_stdin(raw).unwrap();
        assert_eq!(input.tool_name, "Edit");
    }

    #[test]
    fn is_semantic_query_requires_3_words() {
        assert!(!is_semantic_query("fn main"));
        assert!(!is_semantic_query("embed_query"));
        assert!(is_semantic_query("how does embedding work"));
        assert!(is_semantic_query("database connection pool"));
    }

    #[test]
    fn looks_like_identifier_rules() {
        assert!(looks_like_identifier("embed_query"));
        assert!(looks_like_identifier("MyStruct::new"));
        assert!(!looks_like_identifier("a")); // too short
        assert!(!looks_like_identifier("foo bar")); // has space
        assert!(!looks_like_identifier("fn.*main")); // regex meta
    }

    #[test]
    fn copilot_grep_normalized() {
        let raw = r#"{"toolName":"grep","toolArgs":{"pattern":"how does auth work"}}"#;
        let input = HookInput::from_stdin(raw).unwrap();
        assert_eq!(input.tool_name, "Grep");
        assert_eq!(input.tool_input["pattern"], "how does auth work");
    }

    #[test]
    fn copilot_read_with_path_key() {
        let raw = r#"{"toolName":"view","toolArgs":{"path":"src/lib.rs"}}"#;
        let input = HookInput::from_stdin(raw).unwrap();
        assert_eq!(input.tool_name, "Read");
        assert_eq!(input.tool_input["file_path"], "src/lib.rs");
    }

    #[test]
    fn snake_case_view_normalized_to_read() {
        // Newer Copilot/Codex builds use the snake_case shape with harness tool
        // names; it must canonicalize just like the legacy camelCase shape does.
        let raw = r#"{"tool_name":"view","tool_input":{"path":"src/main.rs"}}"#;
        let input = HookInput::from_stdin(raw).unwrap();
        assert_eq!(input.tool_name, "Read");
        assert_eq!(input.tool_input["file_path"], "src/main.rs");
    }

    #[test]
    fn bash_rewrite_output_has_required_hook_event_name() {
        // Claude Code ignores `hookSpecificOutput` (so the rewrite never applies)
        // unless `hookEventName` is present and set to "PreToolUse".
        let out = bash_rewrite_output("git status --short", "test reason");
        let hso = &out["hookSpecificOutput"];
        assert_eq!(hso["hookEventName"], "PreToolUse");
        assert_eq!(hso["permissionDecision"], "allow");
        assert_eq!(hso["permissionDecisionReason"], "test reason");
        assert_eq!(hso["updatedInput"]["command"], "git status --short");
        // Aliases for non-Claude harnesses (Copilot/Codex) carry the same value.
        assert_eq!(hso["updatedInput"]["CommandLine"], "git status --short");
        assert_eq!(hso["updatedInput"]["commandLine"], "git status --short");
        assert_eq!(hso["updatedInput"]["command_line"], "git status --short");
    }
}