const mysql = require('mysql2/promise');
const { hashPassword } = require('./auth');

function createPool() {
  return mysql.createPool({
    host: process.env.DB_HOST || '127.0.0.1',
    port: Number(process.env.DB_PORT || 3306),
    user: process.env.DB_USER || 'signage_user',
    password: process.env.DB_PASSWORD || 'signage_password',
    database: process.env.DB_NAME || 'signage',
    waitForConnections: true,
    connectionLimit: 10,
    namedPlaceholders: true
  });
}

async function addColumnIfMissing(pool, tableName, columnName, columnDefinition) {
  const [rows] = await pool.query(
    `SELECT COUNT(*) AS column_count
     FROM information_schema.columns
     WHERE table_schema = DATABASE()
       AND table_name = ?
       AND column_name = ?`,
    [tableName, columnName]
  );

  if (rows.length && Number(rows[0].column_count) > 0) {
    return;
  }

  await pool.query(`ALTER TABLE \`${tableName}\` ADD COLUMN \`${columnName}\` ${columnDefinition}`);
}

async function ensureSchema(pool) {
  await pool.query(`
    CREATE TABLE IF NOT EXISTS canvas_sizes (
      id INT AUTO_INCREMENT PRIMARY KEY,
      name VARCHAR(255) NOT NULL,
      width INT NOT NULL,
      height INT NOT NULL,
      created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
      modified_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
      UNIQUE KEY uq_canvas_sizes_dimensions (width, height)
    ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci
  `);
  await addColumnIfMissing(pool, 'canvas_sizes', 'modified_at', 'TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP');
  await addColumnIfMissing(pool, 'canvas_sizes', 'created_by', 'INT NULL');
  await addColumnIfMissing(pool, 'canvas_sizes', 'modified_by', 'INT NULL');

  await pool.query(`
    CREATE TABLE IF NOT EXISTS playlists (
      id INT AUTO_INCREMENT PRIMARY KEY,
      name VARCHAR(255) NOT NULL,
      fade_between_slides TINYINT(1) NOT NULL DEFAULT 0,
      created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
      modified_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP
    ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci
  `);
  await addColumnIfMissing(pool, 'playlists', 'fade_between_slides', 'TINYINT(1) NOT NULL DEFAULT 0');
  await addColumnIfMissing(pool, 'playlists', 'modified_at', 'TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP');
  await addColumnIfMissing(pool, 'playlists', 'created_by', 'INT NULL');
  await addColumnIfMissing(pool, 'playlists', 'modified_by', 'INT NULL');

  await pool.query(`
    CREATE TABLE IF NOT EXISTS slide_templates (
      id INT AUTO_INCREMENT PRIMARY KEY,
      name VARCHAR(255) NOT NULL,
      canvas_size_id INT NULL,
      background_image_path VARCHAR(512) NULL,
      created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
      modified_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP
    ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci
  `);

  await addColumnIfMissing(pool, 'slide_templates', 'canvas_size_id', 'INT NULL');
  await addColumnIfMissing(pool, 'slide_templates', 'background_image_path', 'VARCHAR(512) NULL');
  await addColumnIfMissing(pool, 'slide_templates', 'modified_at', 'TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP');
  await addColumnIfMissing(pool, 'slide_templates', 'created_by', 'INT NULL');
  await addColumnIfMissing(pool, 'slide_templates', 'modified_by', 'INT NULL');

  await pool.query(`
    INSERT IGNORE INTO canvas_sizes (name, width, height) VALUES
      ('Full HD', 1920, 1080),
      ('HD', 1280, 720),
      ('4K UHD', 3840, 2160),
      ('Portrait Full HD', 1080, 1920),
      ('Portrait HD', 720, 1280)
  `);

  const [legacyTemplateColumns] = await pool.query(`
    SELECT COUNT(*) AS column_count
    FROM information_schema.columns
    WHERE table_schema = DATABASE()
      AND table_name = 'slide_templates'
      AND column_name IN ('canvas_width', 'canvas_height')
  `);
  if (legacyTemplateColumns[0] && Number(legacyTemplateColumns[0].column_count) === 2) {
    await pool.query(`
      UPDATE slide_templates st
      JOIN canvas_sizes cs ON cs.width = st.canvas_width AND cs.height = st.canvas_height
      SET st.canvas_size_id = cs.id
      WHERE st.canvas_size_id IS NULL
    `);
  }

  await pool.query(`
    CREATE TABLE IF NOT EXISTS slide_template_regions (
      id INT AUTO_INCREMENT PRIMARY KEY,
      template_id INT NOT NULL,
      region_key VARCHAR(100) NOT NULL,
      region_type VARCHAR(20) NOT NULL,
      label VARCHAR(255) NOT NULL,
      x INT NOT NULL DEFAULT 0,
      y INT NOT NULL DEFAULT 0,
      width INT NOT NULL DEFAULT 100,
      height INT NOT NULL DEFAULT 100,
      z_index INT NOT NULL DEFAULT 0,
      created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
      modified_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP
    ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci
  `);

  await addColumnIfMissing(pool, 'slide_template_regions', 'font_family', 'VARCHAR(100) NULL');
  await addColumnIfMissing(pool, 'slide_template_regions', 'modified_at', 'TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP');
  await addColumnIfMissing(pool, 'slide_template_regions', 'created_by', 'INT NULL');
  await addColumnIfMissing(pool, 'slide_template_regions', 'modified_by', 'INT NULL');

  await pool.query(`
    CREATE TABLE IF NOT EXISTS slides (
      id INT AUTO_INCREMENT PRIMARY KEY,
      title VARCHAR(255) NOT NULL,
      body TEXT NULL,
      template_id INT NULL,
      content_json JSON NULL,
      media_path VARCHAR(512) NULL,
      media_type VARCHAR(100) NULL,
      created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
      modified_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP
    ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci
  `);

  await addColumnIfMissing(pool, 'slides', 'body', 'TEXT NULL');
  await addColumnIfMissing(pool, 'slides', 'template_id', 'INT NULL');
  await addColumnIfMissing(pool, 'slides', 'content_json', 'JSON NULL');
  await addColumnIfMissing(pool, 'slides', 'media_path', 'VARCHAR(512) NULL');
  await addColumnIfMissing(pool, 'slides', 'media_type', 'VARCHAR(100) NULL');
  await addColumnIfMissing(pool, 'slides', 'modified_at', 'TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP');
  await addColumnIfMissing(pool, 'slides', 'created_by', 'INT NULL');
  await addColumnIfMissing(pool, 'slides', 'modified_by', 'INT NULL');

  await pool.query(`
    CREATE TABLE IF NOT EXISTS playlist_slides (
      id INT AUTO_INCREMENT PRIMARY KEY,
      playlist_id INT NOT NULL,
      slide_id INT NOT NULL,
      position INT NOT NULL DEFAULT 0,
      duration_seconds INT NOT NULL DEFAULT 10,
      schedule_mode VARCHAR(20) NOT NULL DEFAULT 'always',
      schedule_start_datetime DATETIME NULL,
      schedule_end_datetime DATETIME NULL,
      schedule_start_time TIME NULL,
      schedule_end_time TIME NULL,
      schedule_days_json JSON NULL,
      created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
      modified_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
      CONSTRAINT fk_playlist_slides_playlist FOREIGN KEY (playlist_id) REFERENCES playlists(id) ON DELETE CASCADE,
      CONSTRAINT fk_playlist_slides_slide FOREIGN KEY (slide_id) REFERENCES slides(id) ON DELETE CASCADE
    ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci
  `);

  await addColumnIfMissing(pool, 'playlist_slides', 'duration_seconds', 'INT NOT NULL DEFAULT 10');
  await addColumnIfMissing(pool, 'playlist_slides', 'schedule_mode', "VARCHAR(20) NOT NULL DEFAULT 'always'");
  await addColumnIfMissing(pool, 'playlist_slides', 'schedule_start_datetime', 'DATETIME NULL');
  await addColumnIfMissing(pool, 'playlist_slides', 'schedule_end_datetime', 'DATETIME NULL');
  await addColumnIfMissing(pool, 'playlist_slides', 'schedule_start_time', 'TIME NULL');
  await addColumnIfMissing(pool, 'playlist_slides', 'schedule_end_time', 'TIME NULL');
  await addColumnIfMissing(pool, 'playlist_slides', 'schedule_days_json', 'JSON NULL');
  await addColumnIfMissing(pool, 'playlist_slides', 'modified_at', 'TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP');
  await addColumnIfMissing(pool, 'playlist_slides', 'created_by', 'INT NULL');
  await addColumnIfMissing(pool, 'playlist_slides', 'modified_by', 'INT NULL');

  await pool.query(`
    CREATE TABLE IF NOT EXISTS screens (
      id INT AUTO_INCREMENT PRIMARY KEY,
      name VARCHAR(255) NOT NULL,
      slug VARCHAR(255) NOT NULL UNIQUE,
      playlist_id INT NULL,
      created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
      modified_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
      CONSTRAINT fk_screens_playlist FOREIGN KEY (playlist_id) REFERENCES playlists(id) ON DELETE SET NULL
    ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci
  `);

  await addColumnIfMissing(pool, 'screens', 'playlist_id', 'INT NULL');
  await addColumnIfMissing(pool, 'screens', 'modified_at', 'TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP');
  await addColumnIfMissing(pool, 'screens', 'created_by', 'INT NULL');
  await addColumnIfMissing(pool, 'screens', 'modified_by', 'INT NULL');

  await pool.query(`
    CREATE TABLE IF NOT EXISTS users (
      id INT AUTO_INCREMENT PRIMARY KEY,
      name VARCHAR(255) NULL,
      username VARCHAR(255) NOT NULL UNIQUE,
      password_hash CHAR(64) NOT NULL,
      password_salt VARCHAR(64) NOT NULL,
      password_iterations INT NOT NULL,
      created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
      modified_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP
    ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci
  `);
  await addColumnIfMissing(pool, 'users', 'name', 'VARCHAR(255) NULL');
  await addColumnIfMissing(pool, 'users', 'password_hash', 'CHAR(64) NOT NULL');
  await addColumnIfMissing(pool, 'users', 'password_salt', 'VARCHAR(64) NOT NULL');
  await addColumnIfMissing(pool, 'users', 'password_iterations', 'INT NOT NULL');
  await addColumnIfMissing(pool, 'users', 'modified_at', 'TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP');
  await addColumnIfMissing(pool, 'users', 'created_by', 'INT NULL');
  await addColumnIfMissing(pool, 'users', 'modified_by', 'INT NULL');

  await pool.query(`
    CREATE TABLE IF NOT EXISTS auth_sessions (
      session_hash CHAR(64) PRIMARY KEY,
      user_id INT NOT NULL,
      expires_at DATETIME NOT NULL,
      created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
      last_used_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
      CONSTRAINT fk_auth_sessions_user FOREIGN KEY (user_id) REFERENCES users(id) ON DELETE CASCADE
    ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci
  `);
  await addColumnIfMissing(pool, 'auth_sessions', 'created_by', 'INT NULL');
  await addColumnIfMissing(pool, 'auth_sessions', 'modified_by', 'INT NULL');

  const [userCountRows] = await pool.query('SELECT COUNT(*) AS user_count FROM users');
  if (!userCountRows.length || Number(userCountRows[0].user_count) === 0) {
    const username = String(process.env.DEFAULT_ADMIN_USERNAME || 'admin').trim() || 'admin';
    const name = String(process.env.DEFAULT_ADMIN_NAME || 'Admin').trim() || 'Admin';
    const password = String(process.env.DEFAULT_ADMIN_PASSWORD || 'admin').trim() || 'admin';
    const passwordRecord = hashPassword(password);
    await pool.query(
      'INSERT INTO users (name, username, password_hash, password_salt, password_iterations, created_by, modified_by) VALUES (?, ?, ?, ?, ?, ?, ?)',
      [name, username, passwordRecord.hash, passwordRecord.salt, passwordRecord.iterations, null, null]
    );
  }

  await pool.query('UPDATE users SET name = username WHERE name IS NULL OR name = ""');
}

module.exports = {
  createPool,
  ensureSchema
};