package store

import (
	"database/sql"
	"sync"

	_ "modernc.org/sqlite"
)

type Store struct {
	db *sql.DB
	mu sync.Mutex
}

func New(dbPath string) (*Store, error) {
	db, err := sql.Open("sqlite", dbPath+"?_pragma=busy_timeout(5000)&_pragma=journal_mode(WAL)")
	if err != nil {
		return nil, err
	}
	s := &Store{db: db}
	if err := s.migrate(); err != nil {
		db.Close()
		return nil, err
	}
	return s, nil
}

func (s *Store) Close() error {
	return s.db.Close()
}

func (s *Store) migrate() error {
	_, err := s.db.Exec(`
		CREATE TABLE IF NOT EXISTS messages (
			id         INTEGER PRIMARY KEY AUTOINCREMENT,
			room_id    TEXT NOT NULL,
			agent      TEXT NOT NULL,
			role       TEXT NOT NULL,
			content    TEXT NOT NULL DEFAULT '',
			filename   TEXT,
			title      TEXT,
			group_id   INTEGER,
			created_at TEXT NOT NULL DEFAULT (datetime('now'))
		);
		CREATE INDEX IF NOT EXISTS idx_msg_room ON messages(room_id, created_at);
		CREATE INDEX IF NOT EXISTS idx_msg_group ON messages(group_id);

		CREATE TABLE IF NOT EXISTS token_usage (
			id                INTEGER PRIMARY KEY AUTOINCREMENT,
			room_id           TEXT NOT NULL,
			agent             TEXT NOT NULL,
			prompt_tokens     INTEGER NOT NULL DEFAULT 0,
			completion_tokens INTEGER NOT NULL DEFAULT 0,
			total_tokens      INTEGER NOT NULL DEFAULT 0,
			created_at        TEXT NOT NULL DEFAULT (datetime('now'))
		);
		CREATE INDEX IF NOT EXISTS idx_tu_room ON token_usage(room_id);

		CREATE TABLE IF NOT EXISTS schedules (
			id          TEXT PRIMARY KEY,
			room_id     TEXT NOT NULL,
			cron        TEXT NOT NULL,
			message     TEXT NOT NULL,
			user_name   TEXT NOT NULL DEFAULT 'scheduler',
			enabled     INTEGER NOT NULL DEFAULT 1,
			once        INTEGER NOT NULL DEFAULT 0,
			created_at  TEXT NOT NULL DEFAULT (datetime('now')),
			last_run_at TEXT
		);
		CREATE INDEX IF NOT EXISTS idx_sch_room ON schedules(room_id);

		CREATE TABLE IF NOT EXISTS file_versions (
			id         INTEGER PRIMARY KEY AUTOINCREMENT,
			room_id    TEXT NOT NULL,
			filename   TEXT NOT NULL,
			content    TEXT NOT NULL,
			agent      TEXT NOT NULL DEFAULT '',
			version    INTEGER NOT NULL DEFAULT 1,
			created_at TEXT NOT NULL DEFAULT (datetime('now'))
		);
		CREATE INDEX IF NOT EXISTS idx_fv_room_file ON file_versions(room_id, filename);
	`)
	if err != nil {
		return err
	}

	// 安全添加 part_type 列（SQLite 不支持 ALTER TABLE ... IF NOT EXISTS）
	var hasPartType bool
	rows, err := s.db.Query(`PRAGMA table_info(messages)`)
	if err != nil {
		return err
	}
	defer rows.Close()
	for rows.Next() {
		var cid int
		var name, typ string
		var notnull int
		var dfltValue *string
		var pk int
		if err := rows.Scan(&cid, &name, &typ, &notnull, &dfltValue, &pk); err != nil {
			return err
		}
		if name == "part_type" {
			hasPartType = true
			break
		}
	}
	if !hasPartType {
		_, err = s.db.Exec(`ALTER TABLE messages ADD COLUMN part_type TEXT NOT NULL DEFAULT 'text'`)
		if err != nil {
			return err
		}
	}

	return nil
}