import path from 'path'
import fs from 'fs'
import Database from 'better-sqlite3'

const CONFIG_PATH = process.env.CONFIG_PATH ?? process.cwd()
const DB_PATH = path.resolve(CONFIG_PATH, 'medialore.db')

let _db: Database.Database | null = null

export function getDb(): Database.Database {
  if (_db) return _db
  _db = new Database(DB_PATH)
  _db.pragma('journal_mode = WAL')
  _db.pragma('foreign_keys = ON')
  initDb(_db)
  return _db
}

function initDb(db: Database.Database): void {
  db.exec(`
    CREATE TABLE IF NOT EXISTS tag_categories (
      id   TEXT PRIMARY KEY,
      name TEXT NOT NULL UNIQUE
    );

    CREATE TABLE IF NOT EXISTS tags (
      id          TEXT PRIMARY KEY,
      name        TEXT NOT NULL,
      category_id TEXT NOT NULL REFERENCES tag_categories(id) ON DELETE CASCADE
    );

    CREATE UNIQUE INDEX IF NOT EXISTS tags_name_category ON tags(name, category_id);

    CREATE TABLE IF NOT EXISTS media_tags (
      item_key TEXT NOT NULL,
      tag_id   TEXT NOT NULL REFERENCES tags(id) ON DELETE CASCADE,
      PRIMARY KEY (item_key, tag_id)
    );

    CREATE TABLE IF NOT EXISTS libraries (
      id   TEXT PRIMARY KEY,
      name TEXT NOT NULL,
      path TEXT NOT NULL,
      type TEXT NOT NULL CHECK(type IN ('games', 'mixed', 'movies', 'tv')),
      cover_ext TEXT NULL
    );

    CREATE TABLE IF NOT EXISTS users (
      id            TEXT PRIMARY KEY,
      username      TEXT NOT NULL UNIQUE,
      password_hash TEXT NOT NULL,
      role          TEXT NOT NULL CHECK(role IN ('admin', 'user')),
      created_at    INTEGER NOT NULL
    );

    CREATE TABLE IF NOT EXISTS library_permissions (
      user_id    TEXT NOT NULL REFERENCES users(id) ON DELETE CASCADE,
      library_id TEXT NOT NULL REFERENCES libraries(id) ON DELETE CASCADE,
      PRIMARY KEY (user_id, library_id)
    );

    CREATE TABLE IF NOT EXISTS user_settings (
      user_id         TEXT PRIMARY KEY REFERENCES users(id) ON DELETE CASCADE,
      mixed_autoplay  INTEGER NOT NULL DEFAULT 1,
      mixed_loop      INTEGER NOT NULL DEFAULT 1,
      mixed_muted     INTEGER NOT NULL DEFAULT 1,
      movies_autoplay INTEGER NOT NULL DEFAULT 1,
      movies_loop     INTEGER NOT NULL DEFAULT 0,
      movies_muted    INTEGER NOT NULL DEFAULT 0,
      tv_autoplay     INTEGER NOT NULL DEFAULT 1,
      tv_loop         INTEGER NOT NULL DEFAULT 0,
      tv_muted        INTEGER NOT NULL DEFAULT 0
    );

    CREATE TABLE IF NOT EXISTS app_settings (
      key   TEXT PRIMARY KEY,
      value TEXT NOT NULL
    );

    CREATE TABLE IF NOT EXISTS media_items (
      id          INTEGER PRIMARY KEY AUTOINCREMENT,
      library_id  TEXT NOT NULL REFERENCES libraries(id) ON DELETE CASCADE,
      item_key    TEXT NOT NULL UNIQUE,
      item_type   TEXT NOT NULL CHECK(item_type IN ('movie','tv_series','tv_season','tv_episode','game','game_series','mixed_file')),
      parent_key  TEXT,
      title       TEXT,
      year        INTEGER,
      plot        TEXT,
      genres      TEXT,
      metadata    TEXT,
      file_path   TEXT,
      fingerprint TEXT,
      scanned_at  INTEGER NOT NULL
    );

    CREATE INDEX IF NOT EXISTS media_items_library_id ON media_items(library_id);
    CREATE INDEX IF NOT EXISTS media_items_parent_key ON media_items(parent_key);
    CREATE INDEX IF NOT EXISTS media_items_fingerprint ON media_items(fingerprint);
  `)

  migrateLibrariesType(db)
  migrateMediaItemsSchema(db)
  migrateMediaItemsFingerprint(db)
  migrateMediaTagsToItemKey(db)
  migrateMediaItemsAiTagged(db)
  migrateMediaItemsAiFields(db)
  seedAppSettings(db)
}

function seedAppSettings(db: Database.Database): void {
  const defaults: Record<string, string> = {
    scan_schedule: '0 * * * *',
    scan_enabled: 'true',
    scan_last_ran: '',
    ai_enabled: 'false',
    ai_endpoint: '',
    ai_model: '',
    preferred_language: 'English',
  }
  const insert = db.prepare(
    'INSERT OR IGNORE INTO app_settings (key, value) VALUES (?, ?)'
  )
  for (const [key, value] of Object.entries(defaults)) {
    insert.run(key, value)
  }
}

function migrateMediaItemsSchema(db: Database.Database): void {
  const row = db
    .prepare("SELECT sql FROM sqlite_master WHERE type='table' AND name='media_items'")
    .get() as { sql: string } | undefined

  if (!row) return

  const needsFilePath = !row.sql.includes('file_path')
  const needsMixedFile = !row.sql.includes("'mixed_file'")

  if (!needsFilePath && !needsMixedFile) return

  // Determine whether the current table already has file_path (partial migration)
  const hasFilePath = !needsFilePath ? 'file_path,' : 'NULL as file_path,'

  db.exec(`
    BEGIN TRANSACTION;
    CREATE TABLE media_items_new (
      id          INTEGER PRIMARY KEY AUTOINCREMENT,
      library_id  TEXT NOT NULL REFERENCES libraries(id) ON DELETE CASCADE,
      item_key    TEXT NOT NULL UNIQUE,
      item_type   TEXT NOT NULL CHECK(item_type IN (
                    'movie','tv_series','tv_season','tv_episode',
                    'game','game_series','mixed_file')),
      parent_key  TEXT,
      title       TEXT,
      year        INTEGER,
      plot        TEXT,
      genres      TEXT,
      metadata    TEXT,
      file_path   TEXT,
      scanned_at  INTEGER NOT NULL
    );
    INSERT INTO media_items_new
      SELECT id, library_id, item_key, item_type, parent_key,
             title, year, plot, genres, metadata,
             ${hasFilePath}
             scanned_at
      FROM media_items;
    DROP TABLE media_items;
    ALTER TABLE media_items_new RENAME TO media_items;
    CREATE INDEX media_items_library_id ON media_items(library_id);
    CREATE INDEX media_items_parent_key ON media_items(parent_key);
    COMMIT;
  `)
}

function migrateMediaItemsFingerprint(db: Database.Database): void {
  const row = db
    .prepare("SELECT sql FROM sqlite_master WHERE type='table' AND name='media_items'")
    .get() as { sql: string } | undefined
  if (row && !row.sql.includes('fingerprint')) {
    db.exec(`
      ALTER TABLE media_items ADD COLUMN fingerprint TEXT;
      CREATE INDEX IF NOT EXISTS media_items_fingerprint ON media_items(fingerprint);
    `)
  }
}

function migrateMediaTagsToItemKey(db: Database.Database): void {
  const row = db
    .prepare("SELECT sql FROM sqlite_master WHERE type='table' AND name='media_tags'")
    .get() as { sql: string } | undefined
  if (!row || !row.sql.includes('media_key')) return // Already migrated or table doesn't exist

  // Create replacement table with item_key column
  db.exec(`
    CREATE TABLE media_tags_new (
      item_key TEXT NOT NULL,
      tag_id   TEXT NOT NULL REFERENCES tags(id) ON DELETE CASCADE,
      PRIMARY KEY (item_key, tag_id)
    )
  `)

  // Build reverse mapping: short media_key → full item_key
  // Uses same logic as the old itemKeyToMediaKey: libraryId + lastSegment
  const items = db
    .prepare('SELECT item_key FROM media_items')
    .all() as { item_key: string }[]

  const shortToFull: Record<string, string[]> = {}
  for (const { item_key } of items) {
    const firstColon = item_key.indexOf(':')
    const lastColon = item_key.lastIndexOf(':')
    const libraryId = item_key.slice(0, firstColon)
    const shortId = item_key.slice(lastColon + 1)
    const mediaKey = `${libraryId}:${shortId}`
    ;(shortToFull[mediaKey] ??= []).push(item_key)
  }

  const tagRows = db
    .prepare('SELECT media_key, tag_id FROM media_tags')
    .all() as { media_key: string; tag_id: string }[]

  const insert = db.prepare('INSERT OR IGNORE INTO media_tags_new (item_key, tag_id) VALUES (?, ?)')
  db.transaction(() => {
    for (const { media_key, tag_id } of tagRows) {
      const candidates = shortToFull[media_key]
      if (!candidates || candidates.length !== 1) continue // orphaned or ambiguous collision
      insert.run(candidates[0], tag_id)
    }
  })()

  db.exec(`
    DROP TABLE media_tags;
    ALTER TABLE media_tags_new RENAME TO media_tags;
  `)
}

function migrateMediaItemsAiTagged(db: Database.Database): void {
  const row = db
    .prepare("SELECT sql FROM sqlite_master WHERE type='table' AND name='media_items'")
    .get() as { sql: string } | undefined
  if (row && !row.sql.includes('ai_tagged_at')) {
    db.exec('ALTER TABLE media_items ADD COLUMN ai_tagged_at INTEGER')
  }
}

function migrateMediaItemsAiFields(db: Database.Database): void {
  const row = db
    .prepare("SELECT sql FROM sqlite_master WHERE type='table' AND name='media_items'")
    .get() as { sql: string } | undefined
  if (!row) return
  if (!row.sql.includes('ai_description')) {
    db.exec('ALTER TABLE media_items ADD COLUMN ai_description TEXT')
  }
  if (!row.sql.includes('extracted_text')) {
    db.exec('ALTER TABLE media_items ADD COLUMN extracted_text TEXT')
  }
  if (!row.sql.includes('extracted_text_translated')) {
    db.exec('ALTER TABLE media_items ADD COLUMN extracted_text_translated TEXT')
  }
}

function migrateLibrariesType(db: Database.Database): void {
  const row = db
    .prepare("SELECT sql FROM sqlite_master WHERE type='table' AND name='libraries'")
    .get() as { sql: string } | undefined

  if (row && !row.sql.includes("'movies'")) {
    db.exec(`
      BEGIN TRANSACTION;
      CREATE TABLE libraries_new (
        id        TEXT PRIMARY KEY,
        name      TEXT NOT NULL,
        path      TEXT NOT NULL,
        type      TEXT NOT NULL CHECK(type IN ('games', 'mixed', 'movies', 'tv')),
        cover_ext TEXT NULL
      );
      INSERT INTO libraries_new SELECT * FROM libraries;
      DROP TABLE libraries;
      ALTER TABLE libraries_new RENAME TO libraries;
      COMMIT;
    `)
  }
}