//! Text search tools: Grep (line matching) and Glob (filename pattern matching).
//!
//! `Grep` searches file contents recursively with regex or literal fallback.
//! `Glob` lists files matching a given glob pattern under a directory.

use crate::tools::{resolve_path, Tool, ToolCtx};
use anyhow::Result;
use globset::{GlobBuilder, GlobSetBuilder};
use ignore::Walk;
use serde_json::{json, Value};
use std::fs;
use tracing::{debug, info, instrument, warn};

/// Search for a regex (or literal) pattern in file contents under a directory.
///
/// Flow: resolve path → walk files → regex-match each line → collect results.
/// Falls back to substring search when the pattern is not a valid regex.
pub struct Grep;

impl Tool for Grep {
    fn name(&self) -> &'static str {
        "grep"
    }

    fn description(&self) -> &'static str {
        "Search for a pattern in files using recursive text search"
    }

    fn parameters(&self) -> Value {
        json!({
            "type": "object",
            "properties": {
                "pattern": {
                    "type": "string",
                    "description": "Text pattern to search for"
                },
                "path": {
                    "type": "string",
                    "description": "Path to search in (relative to workspace root)"
                }
            },
            "required": ["pattern", "path"]
        })
    }

    #[instrument(skip(self, ctx, args))]
    fn run(&self, ctx: &ToolCtx, args: &Value) -> Result<String> {
        let pattern = crate::tools::arg_str(args, "pattern")?;
        let rel = crate::tools::arg_str(args, "path")?;
        let path = resolve_path(&ctx.workspaces, &rel)?;

        if !path.exists() {
            warn!(rel = %rel, "grep path does not exist");
            anyhow::bail!("path '{rel}' does not exist");
        }
        if !path.is_dir() {
            warn!(rel = %rel, "grep path is not a directory");
            anyhow::bail!("path '{rel}' is not a directory");
        }

        info!(pattern = %pattern, root = %rel, "grep search starting");
        let mut results: Vec<(String, usize, String)> = Vec::new();
        for entry in Walk::new(&path).flatten() {
            let file_path = entry.path();
            if !file_path.is_file() {
                continue;
            }
            if let Ok(content) = fs::read_to_string(file_path) {
                for (i, line) in content.lines().enumerate() {
                    let is_match = if let Ok(re) = regex::Regex::new(&pattern) {
                        re.is_match(line)
                    } else {
                        // Fall back to literal substring search when the
                        // pattern is not a valid regex.
                        line.contains(&pattern)
                    };
                    if is_match {
                        let rel_path = file_path
                            .strip_prefix(&path)
                            .unwrap_or(file_path)
                            .display()
                            .to_string();
                        results.push((rel_path, i + 1, line.to_string()));
                    }
                }
            }
        }

        if results.is_empty() {
            debug!(pattern = %pattern, "grep found no matches");
            return Ok(format!("no matches found for '{pattern}' in {rel}"));
        }
        info!(match_count = results.len(), "grep search completed");
        let output = results
            .iter()
            .map(|(f, line, text)| format!("{f}:{line}:{text}"))
            .collect::<Vec<_>>()
            .join("\n");
        Ok(format!("found {} matches:\n{}", results.len(), output))
    }
}

/// List files matching a glob pattern under a directory root.
///
/// Flow: resolve root → build glob set from pattern → walk files → filter by
/// glob set → sort results.
pub struct Glob;

impl Tool for Glob {
    fn name(&self) -> &'static str {
        "glob"
    }

    fn description(&self) -> &'static str {
        "List files matching a glob pattern"
    }

    fn parameters(&self) -> Value {
        json!({
            "type": "object",
            "properties": {
                "pattern": {
                    "type": "string",
                    "description": "Glob pattern to match files (e.g. '**/*.rs')"
                },
                "path": {
                    "type": "string",
                    "description": "Root path to search from (relative to workspace root)"
                }
            },
            "required": ["pattern", "path"]
        })
    }

    #[instrument(skip(self, ctx, args))]
    fn run(&self, ctx: &ToolCtx, args: &Value) -> Result<String> {
        let pat_str = crate::tools::arg_str(args, "pattern")?;
        let rel = crate::tools::arg_str(args, "path")?;
        let root = resolve_path(&ctx.workspaces, &rel)?;

        if !root.exists() || !root.is_dir() {
            warn!(rel = %rel, "glob root is not a valid directory");
            anyhow::bail!("path '{rel}' is not a valid directory");
        }

        info!(pattern = %pat_str, root = %rel, "glob search starting");
        let mut builder = GlobSetBuilder::new();
        let full_pattern = root.join(&pat_str).display().to_string();
        builder.add(
            GlobBuilder::new(&full_pattern)
                .build()
                .map_err(|e| anyhow::anyhow!("invalid glob pattern '{pat_str}': {e}"))?,
        );
        let glob_set = builder.build()?;

        let mut matches: Vec<String> = Vec::new();
        for entry in Walk::new(&root).flatten() {
            let p = entry.path();
            if glob_set.is_match(p) {
                let rel_path = p.strip_prefix(&root).unwrap_or(p).display().to_string();
                matches.push(format!("{}{}", rel_path, if p.is_dir() { "/" } else { "" }));
            }
        }
        matches.sort();
        if matches.is_empty() {
            debug!(pattern = %pat_str, "glob found no matches");
            return Ok(format!("no files match '{pat_str}' in {rel}"));
        }
        info!(match_count = matches.len(), "glob search completed");
        Ok(matches.join("\n"))
    }
}