import Database from 'better-sqlite3';
import { mkdirSync, existsSync } from 'fs';
import { dirname } from 'path';

const DB_PATH = process.env.DB_PATH || './data/db/ofapp.db';

const dir = dirname(DB_PATH);
if (!existsSync(dir)) {
  mkdirSync(dir, { recursive: true });
}

const db = new Database(DB_PATH);

db.pragma('journal_mode = WAL');

db.exec(`
  CREATE TABLE IF NOT EXISTS auth_config (
    user_id TEXT,
    cookie TEXT,
    x_bc TEXT,
    app_token TEXT,
    x_of_rev TEXT,
    user_agent TEXT
  );

  CREATE TABLE IF NOT EXISTS download_history (
    id INTEGER PRIMARY KEY AUTOINCREMENT,
    user_id TEXT,
    post_id TEXT,
    media_id TEXT,
    media_type TEXT,
    filename TEXT,
    downloaded_at TEXT
  );

  CREATE TABLE IF NOT EXISTS download_cursors (
    user_id TEXT UNIQUE,
    cursor TEXT,
    posts_downloaded INTEGER
  );

  CREATE TABLE IF NOT EXISTS settings (
    key TEXT PRIMARY KEY,
    value TEXT
  );
`);

// Migration: add posted_at column if missing
const cols = db.prepare("PRAGMA table_info(download_history)").all().map((c) => c.name);
if (!cols.includes('posted_at')) {
  db.exec('ALTER TABLE download_history ADD COLUMN posted_at TEXT');
}

export function getAuthConfig() {
  const row = db.prepare('SELECT * FROM auth_config LIMIT 1').get();
  return row || null;
}

export function saveAuthConfig(config) {
  const del = db.prepare('DELETE FROM auth_config');
  const ins = db.prepare(
    'INSERT INTO auth_config (user_id, cookie, x_bc, app_token, x_of_rev, user_agent) VALUES (?, ?, ?, ?, ?, ?)'
  );

  const upsert = db.transaction((c) => {
    del.run();
    ins.run(c.user_id, c.cookie, c.x_bc, c.app_token, c.x_of_rev, c.user_agent);
  });

  upsert(config);
}

export function isMediaDownloaded(mediaId) {
  const row = db.prepare('SELECT 1 FROM download_history WHERE media_id = ? LIMIT 1').get(String(mediaId));
  return !!row;
}

export function recordDownload(userId, postId, mediaId, mediaType, filename, postedAt) {
  db.prepare(
    'INSERT INTO download_history (user_id, post_id, media_id, media_type, filename, downloaded_at, posted_at) VALUES (?, ?, ?, ?, ?, ?, ?)'
  ).run(String(userId), String(postId), String(mediaId), mediaType, filename, new Date().toISOString(), postedAt || null);
}

export function getDownloadHistory(userId) {
  return db.prepare('SELECT * FROM download_history WHERE user_id = ? ORDER BY downloaded_at DESC').all(String(userId));
}

export function saveCursor(userId, cursor, postsDownloaded) {
  db.prepare(
    'INSERT INTO download_cursors (user_id, cursor, posts_downloaded) VALUES (?, ?, ?) ON CONFLICT(user_id) DO UPDATE SET cursor = excluded.cursor, posts_downloaded = excluded.posts_downloaded'
  ).run(String(userId), cursor, postsDownloaded);
}

export function getCursor(userId) {
  return db.prepare('SELECT cursor, posts_downloaded FROM download_cursors WHERE user_id = ?').get(String(userId)) || null;
}

export function clearCursor(userId) {
  db.prepare('DELETE FROM download_cursors WHERE user_id = ?').run(String(userId));
}

export function getPostDateByFilename(filename) {
  const row = db.prepare('SELECT posted_at FROM download_history WHERE filename = ? LIMIT 1').get(filename);
  return row?.posted_at || null;
}

export function getSetting(key) {
  const row = db.prepare('SELECT value FROM settings WHERE key = ?').get(key);
  return row ? row.value : null;
}

export function setSetting(key, value) {
  db.prepare(
    'INSERT INTO settings (key, value) VALUES (?, ?) ON CONFLICT(key) DO UPDATE SET value = excluded.value'
  ).run(key, value);
}

export function getAllSettings() {
  const rows = db.prepare('SELECT key, value FROM settings').all();
  const obj = {};
  for (const row of rows) obj[row.key] = row.value;
  return obj;
}

export function getDownloadStats() {
  return db.prepare(
    'SELECT user_id, COUNT(*) as file_count, MAX(downloaded_at) as last_download FROM download_history GROUP BY user_id'
  ).all();
}