import Database from 'better-sqlite3';
import { readFileSync, mkdirSync } from 'node:fs';
import { dirname, resolve } from 'node:path';
import { fileURLToPath } from 'node:url';
import { randomUUID } from 'node:crypto';

const __dirname = dirname(fileURLToPath(import.meta.url));

let db;

export function initDb(dbPath) {
    const abs = resolve(dbPath);
    mkdirSync(dirname(abs), { recursive: true });
    db = new Database(abs);
    db.pragma('journal_mode = WAL');
    db.pragma('foreign_keys = ON');
    const schema = readFileSync(resolve(__dirname, 'schema.sql'), 'utf8');
    db.exec(schema);
    runMigrations(db);
    return db;
}

export function getDb() {
    if (!db) throw new Error('DB not initialized');
    return db;
}

// Idempotent migrations for upgrading older DBs that pre-date a column.
function runMigrations(db) {
    const stationCols = new Set(db.prepare("PRAGMA table_info(stations)").all().map((c) => c.name));
    if (!stationCols.has('uuid')) {
        db.exec('ALTER TABLE stations ADD COLUMN uuid TEXT');
    }
    if (!stationCols.has('category')) {
        db.exec('ALTER TABLE stations ADD COLUMN category TEXT');
    }
    if (!stationCols.has('image_path')) {
        db.exec('ALTER TABLE stations ADD COLUMN image_path TEXT');
    }
    if (!stationCols.has('image_source')) {
        db.exec('ALTER TABLE stations ADD COLUMN image_source TEXT');
    }
    const streamCols = new Set(db.prepare("PRAGMA table_info(streams)").all().map((c) => c.name));
    if (!streamCols.has('uuid')) {
        db.exec('ALTER TABLE streams ADD COLUMN uuid TEXT');
    }

    // Backfill UUIDs. For RB stations, prefer the existing source_ref so the
    // public UUID matches the upstream Radio-Browser stationuuid.
    const setStationUuid = db.prepare('UPDATE stations SET uuid = ? WHERE id = ?');
    for (const row of db.prepare("SELECT id, source, source_ref FROM stations WHERE uuid IS NULL OR uuid = ''").all()) {
        const u = (row.source === 'radiobrowser' && row.source_ref) ? row.source_ref : randomUUID();
        setStationUuid.run(u, row.id);
    }

    const setStreamUuid = db.prepare('UPDATE streams SET uuid = ? WHERE id = ?');
    for (const row of db.prepare("SELECT id FROM streams WHERE uuid IS NULL OR uuid = ''").all()) {
        setStreamUuid.run(randomUUID(), row.id);
    }

    db.exec('CREATE UNIQUE INDEX IF NOT EXISTS idx_stations_uuid ON stations(uuid)');
    db.exec('CREATE UNIQUE INDEX IF NOT EXISTS idx_streams_uuid  ON streams(uuid)');
    db.exec('CREATE INDEX        IF NOT EXISTS idx_stations_category ON stations(category)');

    // station_plays gained session/listen-time aggregates so the leaderboard
    // can rank by actual playtime, not just play-button taps.
    const playCols = new Set(db.prepare("PRAGMA table_info(station_plays)").all().map((c) => c.name));
    if (!playCols.has('sessions')) {
        db.exec('ALTER TABLE station_plays ADD COLUMN sessions INTEGER NOT NULL DEFAULT 0');
    }
    if (!playCols.has('total_play_ms')) {
        db.exec('ALTER TABLE station_plays ADD COLUMN total_play_ms INTEGER NOT NULL DEFAULT 0');
    }

    // Multi-user kiosk: per-user metadata + designation of "main" identity.
    const userCols = new Set(db.prepare("PRAGMA table_info(users)").all().map((c) => c.name));
    if (!userCols.has('is_main')) {
        db.exec('ALTER TABLE users ADD COLUMN is_main INTEGER NOT NULL DEFAULT 0');
    }
    if (!userCols.has('avatar_color')) {
        db.exec('ALTER TABLE users ADD COLUMN avatar_color TEXT');
    }
    if (!userCols.has('avatar_emoji')) {
        db.exec('ALTER TABLE users ADD COLUMN avatar_emoji TEXT');
    }
    db.exec('CREATE UNIQUE INDEX IF NOT EXISTS idx_users_only_one_main ON users(is_main) WHERE is_main = 1');

    // Cross-client stream sync: when a room enters 'play', record the wall-clock
    // moment so every client can target the same playhead.
    const stateCols = new Set(db.prepare("PRAGMA table_info(room_state)").all().map((c) => c.name));
    if (!stateCols.has('started_at')) {
        db.exec('ALTER TABLE room_state ADD COLUMN started_at INTEGER');
    }
}