//! libmarlin – public API surface for the Marlin core.
//!
//! Down-stream crates (`cli-bin`, `tui-bin`, tests, plugins) should depend
//! *only* on the helpers re-exported here, never on internal modules
//! directly.  That gives us room to refactor internals without breaking
//! callers.

#![deny(warnings)]

pub mod backup;
pub mod config;
pub mod db;
pub mod error;
pub mod logging;
pub mod scan;
pub mod utils;
pub mod watcher;

#[cfg(test)]
mod utils_tests;
#[cfg(test)]
mod config_tests;
#[cfg(test)]
mod scan_tests;
#[cfg(test)]
mod logging_tests;
#[cfg(test)]
mod db_tests;
#[cfg(test)]
mod facade_tests;
#[cfg(test)]
mod watcher_tests;

use anyhow::{Context, Result};
use rusqlite::Connection;
use std::{fs, path::Path, sync::{Arc, Mutex}};

/// Main handle for interacting with a Marlin database.
pub struct Marlin {
    cfg: config::Config,
    conn: Connection,
}

impl Marlin {
    /// Open using the default config (env override or XDG/CWD fallback),
    /// ensuring parent directories exist and applying migrations.
    pub fn open_default() -> Result<Self> {
        // 1) Load configuration
        let cfg = config::Config::load()?;
        // 2) Ensure the DB's parent directory exists
        if let Some(parent) = cfg.db_path.parent() {
            fs::create_dir_all(parent)?;
        }
        // 3) Open the database and run migrations
        let conn = db::open(&cfg.db_path)
            .context(format!("opening database at {}", cfg.db_path.display()))?;
        Ok(Marlin { cfg, conn })
    }

    /// Open a Marlin instance at the specified database path,
    /// creating parent directories and applying migrations.
    pub fn open_at<P: AsRef<Path>>(db_path: P) -> Result<Self> {
        let db_path = db_path.as_ref();
        // Ensure the specified DB directory exists
        if let Some(parent) = db_path.parent() {
            fs::create_dir_all(parent)?;
        }
        // Build a minimal Config so callers can still inspect cfg.db_path
        let cfg = config::Config { db_path: db_path.to_path_buf() };
        // Open the database and run migrations
        let conn = db::open(db_path)
            .context(format!("opening database at {}", db_path.display()))?;
        Ok(Marlin { cfg, conn })
    }

    /// Recursively index one or more directories.
    pub fn scan<P: AsRef<Path>>(&mut self, paths: &[P]) -> Result<usize> {
        let mut total = 0;
        for p in paths {
            total += scan::scan_directory(&mut self.conn, p.as_ref())?;
        }
        Ok(total)
    }

    /// Attach a hierarchical tag (`foo/bar`) to every _indexed_ file
    /// matching the glob.  Returns the number of files actually updated.
    pub fn tag(&mut self, pattern: &str, tag_path: &str) -> Result<usize> {
        use glob::Pattern;

        // 1) ensure tag hierarchy
        let leaf = db::ensure_tag_path(&self.conn, tag_path)?;

        // 2) collect leaf + ancestors
        let mut tag_ids = Vec::new();
        let mut cur = Some(leaf);
        while let Some(id) = cur {
            tag_ids.push(id);
            cur = self.conn.query_row(
                "SELECT parent_id FROM tags WHERE id = ?1",
                [id],
                |r| r.get::<_, Option<i64>>(0),
            )?;
        }

        // 3) match files by glob against stored paths
        let expanded = shellexpand::tilde(pattern).into_owned();
        let pat = Pattern::new(&expanded)
            .with_context(|| format!("Invalid glob pattern `{}`", expanded))?;

        let mut stmt_all = self.conn.prepare("SELECT id, path FROM files")?;
        let rows = stmt_all.query_map([], |r| Ok((r.get(0)?, r.get(1)?)))?;

        let mut stmt_ins = self.conn.prepare(
            "INSERT OR IGNORE INTO file_tags(file_id, tag_id) VALUES (?1, ?2)",
        )?;

        let mut changed = 0;
        for row in rows {
            let (fid, path_str): (i64, String) = row?;
            let is_match = if expanded.contains(std::path::MAIN_SEPARATOR) {
                pat.matches(&path_str)
            } else {
                Path::new(&path_str)
                    .file_name()
                    .and_then(|n| n.to_str())
                    .map(|n| pat.matches(n))
                    .unwrap_or(false)
            };
            if !is_match {
                continue;
            }

            let mut newly = false;
            for &tid in &tag_ids {
                if stmt_ins.execute([fid, tid])? > 0 {
                    newly = true;
                }
            }
            if newly {
                changed += 1;
            }
        }
        Ok(changed)
    }

    /// Full-text search over path, tags, and attrs, with substring fallback.
    pub fn search(&self, query: &str) -> Result<Vec<String>> {
        let mut stmt = self.conn.prepare(
            "SELECT f.path FROM files_fts JOIN files f ON f.rowid = files_fts.rowid WHERE files_fts MATCH ?1 ORDER BY rank",
        )?;
        let mut hits = stmt.query_map([query], |r| r.get(0))?
            .collect::<std::result::Result<Vec<_>, rusqlite::Error>>()?;

        if hits.is_empty() && !query.contains(':') {
            hits = self.fallback_search(query)?;
        }
        Ok(hits)
    }

    fn fallback_search(&self, term: &str) -> Result<Vec<String>> {
        let needle = term.to_lowercase();
        let mut stmt = self.conn.prepare("SELECT path FROM files")?;
        let rows = stmt.query_map([], |r| r.get(0))?;
        let mut out = Vec::new();
        for res in rows {
            let p: String = res?;
            if p.to_lowercase().contains(&needle) {
                out.push(p.clone());
                continue;
            }
            if let Ok(meta) = fs::metadata(&p) {
                if meta.len() <= 65_536 { 
                    if let Ok(body) = fs::read_to_string(&p) {
                        if body.to_lowercase().contains(&needle) {
                            out.push(p.clone());
                        }
                    }
                }
            }
        }
        Ok(out)
    }

    /// Borrow the raw SQLite connection.
    pub fn conn(&self) -> &Connection {
        &self.conn
    }

    /// Spawn a file-watcher that indexes changes in real time.
    pub fn watch<P: AsRef<Path>>(
        &mut self,
        path: P,
        config: Option<watcher::WatcherConfig>,
    ) -> Result<watcher::FileWatcher> {
        let cfg = config.unwrap_or_default();
        let p = path.as_ref().to_path_buf();
        let new_conn = db::open(&self.cfg.db_path)
            .context("opening database for watcher")?;
        let watcher_db = Arc::new(Mutex::new(db::Database::new(new_conn)));
        
        let mut owned_w = watcher::FileWatcher::new(vec![p], cfg)?;
        owned_w.with_database(watcher_db)?; // Modifies owned_w in place
        owned_w.start()?; // Start the watcher after it has been fully configured
        
        Ok(owned_w) // Return the owned FileWatcher
    }
}