const mysql = require('mysql2/promise');
const fs = require('fs');
const path = require('path');
const crypto = require('crypto');

const CONFIG_PATH = path.join(__dirname, '..', 'data', 'config.json');

let pool = null;
let _configCache = null;
let _configMtime = 0;

function getConfig() {
  try {
    const stat = fs.statSync(CONFIG_PATH);
    if (_configCache && stat.mtimeMs === _configMtime) return _configCache;
    _configCache = JSON.parse(fs.readFileSync(CONFIG_PATH, 'utf-8'));
    _configMtime = stat.mtimeMs;
    return _configCache;
  } catch { return null; }
}

function saveConfig(cfg) {
  const dir = path.dirname(CONFIG_PATH);
  if (!fs.existsSync(dir)) fs.mkdirSync(dir, { recursive: true });
  fs.writeFileSync(CONFIG_PATH, JSON.stringify(cfg, null, 2), 'utf-8');
}

function isInstalled() {
  return fs.existsSync(CONFIG_PATH);
}

async function getPool() {
  if (!pool) {
    const cfg = getConfig();
    if (!cfg) throw new Error('SYSTEM_NOT_INSTALLED');
    pool = mysql.createPool({
      host: cfg.db_host || 'localhost',
      port: cfg.db_port || 3306,
      user: cfg.db_user,
      password: cfg.db_pass,
      database: cfg.db_name,
      waitForConnections: true,
      connectionLimit: 10,
      charset: 'utf8mb4',
      timezone: '+08:00',
    });
    await migrateAdditions(pool);
  }
  return pool;
}

async function query(sql, params = []) {
  const p = await getPool();
  const [rows, fields] = await p.execute(sql, params);
  return rows;
}

async function getRow(sql, params = []) {
  const rows = await query(sql, params);
  return rows[0] || null;
}

async function initSchema(connection) {
  const db = connection || await getPool();

  const createIfNotExists = async (tableName, sql) => {
    const [rows] = await db.execute(`SELECT COUNT(*) as c FROM information_schema.tables WHERE table_schema = DATABASE() AND table_name = ?`, [tableName]);
    if (rows[0].c > 0) return; // Table exists
    await db.execute(sql);
  };

  await createIfNotExists('users', `CREATE TABLE users (
    id INT AUTO_INCREMENT PRIMARY KEY,
    username VARCHAR(50) NOT NULL UNIQUE,
    password VARCHAR(255) NOT NULL,
    email VARCHAR(100) NOT NULL UNIQUE,
    game_name VARCHAR(50) NOT NULL,
    game_uid VARCHAR(50) NOT NULL,
    role ENUM('owner','admin','player') NOT NULL DEFAULT 'player',
    active TINYINT(1) NOT NULL DEFAULT 0,
    email_verified TINYINT(1) NOT NULL DEFAULT 0,
    source ENUM('netease','skin') NOT NULL DEFAULT 'netease',
    verify_token VARCHAR(255),
    verify_expires DATETIME,
    reset_token VARCHAR(255),
    reset_expires DATETIME,
    created_at DATETIME DEFAULT CURRENT_TIMESTAMP,
    updated_at DATETIME DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP
  ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4`);

  await createIfNotExists('tickets', `CREATE TABLE tickets (
    id INT AUTO_INCREMENT PRIMARY KEY,
    user_id INT,
    type ENUM('report','suggestion','appeal','result_appeal') NOT NULL,
    title VARCHAR(100) NOT NULL,
    status ENUM('pending','processing','awaiting_info','appealing','resolved','rejected','closed') NOT NULL DEFAULT 'pending',
    priority ENUM('low','medium','high','urgent') NOT NULL DEFAULT 'medium',
    reporter_game_name VARCHAR(50) NOT NULL,
    reporter_game_uid VARCHAR(50) NOT NULL,
    target_game_name VARCHAR(50),
    target_game_uid VARCHAR(50),
    reason VARCHAR(500),
    description TEXT,
    assigned_to INT,
    claim_note TEXT,
    claimed_at DATETIME,
    tracking_token VARCHAR(255) UNIQUE,
    is_admin_complaint TINYINT(1) NOT NULL DEFAULT 0,
    parent_ticket_id INT,
    created_at DATETIME DEFAULT CURRENT_TIMESTAMP,
    updated_at DATETIME DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
    INDEX idx_type (type),
    INDEX idx_status (status),
    INDEX idx_user (user_id),
    INDEX idx_tracking (tracking_token),
    INDEX idx_assigned (assigned_to)
  ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4`);

  await createIfNotExists('ticket_transfers', `CREATE TABLE ticket_transfers (
    id INT AUTO_INCREMENT PRIMARY KEY,
    ticket_id INT NOT NULL,
    from_user_id INT NOT NULL,
    to_user_id INT NOT NULL,
    reason TEXT,
    created_at DATETIME DEFAULT CURRENT_TIMESTAMP,
    INDEX idx_ticket (ticket_id)
  ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4`);

  await createIfNotExists('attachments', `CREATE TABLE attachments (
    id INT AUTO_INCREMENT PRIMARY KEY,
    ticket_id INT NOT NULL,
    original_name VARCHAR(255) NOT NULL,
    stored_name VARCHAR(255) NOT NULL,
    mime_type VARCHAR(100) NOT NULL,
    size INT NOT NULL,
    created_at DATETIME DEFAULT CURRENT_TIMESTAMP,
    INDEX idx_ticket (ticket_id)
  ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4`);

  await createIfNotExists('responses', `CREATE TABLE responses (
    id INT AUTO_INCREMENT PRIMARY KEY,
    ticket_id INT NOT NULL,
    user_id INT,
    content TEXT NOT NULL,
    is_staff TINYINT(1) NOT NULL DEFAULT 0,
    created_at DATETIME DEFAULT CURRENT_TIMESTAMP,
    INDEX idx_ticket (ticket_id)
  ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4`);

  await createIfNotExists('email_templates', `CREATE TABLE email_templates (
    id INT AUTO_INCREMENT PRIMARY KEY,
    code VARCHAR(50) NOT NULL UNIQUE,
    name VARCHAR(100) NOT NULL,
    subject VARCHAR(255) NOT NULL,
    body TEXT NOT NULL,
    description TEXT,
    updated_at DATETIME DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP
  ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4`);

  await createIfNotExists('notification_configs', `CREATE TABLE notification_configs (
    id INT AUTO_INCREMENT PRIMARY KEY,
    name VARCHAR(100) NOT NULL,
    type ENUM('webhook','email') NOT NULL DEFAULT 'webhook',
    webhook_url TEXT,
    events VARCHAR(500) NOT NULL DEFAULT 'all',
    active TINYINT(1) NOT NULL DEFAULT 1,
    created_at DATETIME DEFAULT CURRENT_TIMESTAMP
  ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4`);

  await createIfNotExists('settings', `CREATE TABLE settings (
    k VARCHAR(100) PRIMARY KEY,
    v TEXT NOT NULL,
    label VARCHAR(255),
    updated_at DATETIME DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP
  ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4`);

  await createIfNotExists('captchas', `CREATE TABLE captchas (
    id VARCHAR(255) PRIMARY KEY,
    question VARCHAR(100) NOT NULL,
    answer VARCHAR(20) NOT NULL,
    created_at DATETIME DEFAULT CURRENT_TIMESTAMP
  ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4`);

  await createIfNotExists('polls', `CREATE TABLE polls (
    id INT AUTO_INCREMENT PRIMARY KEY,
    title VARCHAR(200) NOT NULL,
    description TEXT,
    options JSON NOT NULL,
    group_name VARCHAR(100) NOT NULL DEFAULT '',
    server_name VARCHAR(100) NOT NULL DEFAULT '',
    start_time DATETIME,
    end_time DATETIME,
    active TINYINT(1) NOT NULL DEFAULT 1,
    created_by INT,
    created_at DATETIME DEFAULT CURRENT_TIMESTAMP,
    INDEX idx_active (active),
    INDEX idx_group_server (group_name, server_name)
  ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4`);

  await createIfNotExists('poll_votes', `CREATE TABLE poll_votes (
    id INT AUTO_INCREMENT PRIMARY KEY,
    poll_id INT NOT NULL,
    user_id INT NOT NULL,
    option_index INT NOT NULL,
    created_at DATETIME DEFAULT CURRENT_TIMESTAMP,
    UNIQUE KEY uk_poll_user (poll_id, user_id),
    INDEX idx_poll (poll_id)
  ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4`);

  await createIfNotExists('feature_items', `CREATE TABLE feature_items (
    id INT AUTO_INCREMENT PRIMARY KEY,
    title VARCHAR(200) NOT NULL,
    description TEXT,
    group_name VARCHAR(100) NOT NULL DEFAULT '',
    server_name VARCHAR(100) NOT NULL DEFAULT '',
    status ENUM('pending','planned','done') NOT NULL DEFAULT 'pending',
    created_at DATETIME DEFAULT CURRENT_TIMESTAMP
  ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4`);

  await createIfNotExists('feature_votes', `CREATE TABLE feature_votes (
    id INT AUTO_INCREMENT PRIMARY KEY,
    item_id INT NOT NULL,
    user_id INT NOT NULL,
    created_at DATETIME DEFAULT CURRENT_TIMESTAMP,
    UNIQUE KEY uk_item_user (item_id, user_id),
    INDEX idx_item (item_id)
  ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4`);

  await createIfNotExists('feature_comments', `CREATE TABLE feature_comments (
    id INT AUTO_INCREMENT PRIMARY KEY,
    item_id INT NOT NULL,
    user_id INT NOT NULL,
    content TEXT NOT NULL,
    created_at DATETIME DEFAULT CURRENT_TIMESTAMP,
    INDEX idx_item (item_id)
  ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4`);

  await createIfNotExists('server_groups', `CREATE TABLE server_groups (
    id INT AUTO_INCREMENT PRIMARY KEY,
    group_name VARCHAR(100) NOT NULL,
    server_name VARCHAR(100) NOT NULL,
    UNIQUE KEY uk_group_server (group_name, server_name)
  ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4`);

  await createIfNotExists('user_servers', `CREATE TABLE user_servers (
    user_id INT NOT NULL,
    group_name VARCHAR(100) NOT NULL,
    server_name VARCHAR(100) NOT NULL,
    UNIQUE KEY uk_user_server (user_id, group_name, server_name),
    INDEX idx_user (user_id)
  ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4`);

  await createIfNotExists('bans', `CREATE TABLE bans (
    id INT AUTO_INCREMENT PRIMARY KEY,
    player_name VARCHAR(50) NOT NULL,
    player_uid VARCHAR(50),
    source VARCHAR(10) DEFAULT '',
    reason TEXT,
    type ENUM('ban','mute','warn','other') NOT NULL DEFAULT 'ban',
    duration VARCHAR(20) DEFAULT '',
    ticket_id INT,
    created_by INT,
    status ENUM('active','expired','appealed','lifted') NOT NULL DEFAULT 'active',
    created_at DATETIME DEFAULT CURRENT_TIMESTAMP,
    expires_at DATETIME
  ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4`);

  await createIfNotExists('audit_logs', `CREATE TABLE audit_logs (
    id INT AUTO_INCREMENT PRIMARY KEY,
    user_id INT,
    username VARCHAR(50),
    action VARCHAR(100) NOT NULL,
    entity_type VARCHAR(50),
    entity_id INT,
    details TEXT,
    created_at DATETIME DEFAULT CURRENT_TIMESTAMP,
    INDEX idx_created (created_at)
  ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4`);

  await seedTemplates(db);
  await migrateAdditions(db);
}

async function migrateAdditions(db) {
  try { await db.execute("ALTER TABLE tickets ADD COLUMN is_admin_complaint TINYINT(1) NOT NULL DEFAULT 0"); } catch {}
  try { await db.execute("ALTER TABLE tickets ADD COLUMN parent_ticket_id INT"); } catch {}
  try { await db.execute("ALTER TABLE tickets MODIFY type ENUM('report','suggestion','appeal','result_appeal') NOT NULL"); } catch {}
  try { await db.execute("ALTER TABLE tickets MODIFY status ENUM('pending','processing','awaiting_info','appealing','resolved','rejected','closed') NOT NULL"); } catch {}
  try { await db.execute("ALTER TABLE users ADD COLUMN source ENUM('netease','skin') NOT NULL DEFAULT 'netease'"); } catch {}
  try { await db.execute(`CREATE TABLE IF NOT EXISTS user_servers (user_id INT NOT NULL, group_name VARCHAR(100) NOT NULL, server_name VARCHAR(100) NOT NULL, UNIQUE KEY uk_user_server (user_id, group_name, server_name), INDEX idx_user (user_id)) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4`); } catch {}
  try { await db.execute(`CREATE TABLE IF NOT EXISTS bans (id INT AUTO_INCREMENT PRIMARY KEY, player_name VARCHAR(50) NOT NULL, player_uid VARCHAR(50), source VARCHAR(10) DEFAULT '', reason TEXT, type ENUM('ban','mute','warn','other') NOT NULL DEFAULT 'ban', duration VARCHAR(20) DEFAULT '', ticket_id INT, created_by INT, status ENUM('active','expired','appealed','lifted') NOT NULL DEFAULT 'active', created_at DATETIME DEFAULT CURRENT_TIMESTAMP, expires_at DATETIME) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4`); } catch {}
  try { await db.execute("ALTER TABLE bans ADD COLUMN source VARCHAR(10) DEFAULT ''"); } catch {}

  try { await db.execute(`CREATE TABLE IF NOT EXISTS polls (id INT AUTO_INCREMENT PRIMARY KEY, title VARCHAR(200) NOT NULL, description TEXT, options JSON NOT NULL, group_name VARCHAR(100) NOT NULL DEFAULT '', server_name VARCHAR(100) NOT NULL DEFAULT '', start_time DATETIME, end_time DATETIME, active TINYINT(1) NOT NULL DEFAULT 1, created_by INT, created_at DATETIME DEFAULT CURRENT_TIMESTAMP, INDEX idx_active (active), INDEX idx_group_server (group_name, server_name)) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4`); } catch {}
  try { await db.execute(`CREATE TABLE IF NOT EXISTS poll_votes (id INT AUTO_INCREMENT PRIMARY KEY, poll_id INT NOT NULL, user_id INT NOT NULL, option_index INT NOT NULL, created_at DATETIME DEFAULT CURRENT_TIMESTAMP, UNIQUE KEY uk_poll_user (poll_id, user_id), INDEX idx_poll (poll_id)) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4`); } catch {}
  try { await db.execute(`CREATE TABLE IF NOT EXISTS feature_items (id INT AUTO_INCREMENT PRIMARY KEY, title VARCHAR(200) NOT NULL, description TEXT, group_name VARCHAR(100) NOT NULL DEFAULT '', server_name VARCHAR(100) NOT NULL DEFAULT '', status ENUM('pending','planned','done') NOT NULL DEFAULT 'pending', created_at DATETIME DEFAULT CURRENT_TIMESTAMP) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4`); } catch {}
  try { await db.execute(`CREATE TABLE IF NOT EXISTS feature_votes (id INT AUTO_INCREMENT PRIMARY KEY, item_id INT NOT NULL, user_id INT NOT NULL, created_at DATETIME DEFAULT CURRENT_TIMESTAMP, UNIQUE KEY uk_item_user (item_id, user_id), INDEX idx_item (item_id)) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4`); } catch {}
  try { await db.execute(`CREATE TABLE IF NOT EXISTS feature_comments (id INT AUTO_INCREMENT PRIMARY KEY, item_id INT NOT NULL, user_id INT NOT NULL, content TEXT NOT NULL, created_at DATETIME DEFAULT CURRENT_TIMESTAMP, INDEX idx_item (item_id)) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4`); } catch {}
  try { await db.execute(`CREATE TABLE IF NOT EXISTS server_groups (id INT AUTO_INCREMENT PRIMARY KEY, group_name VARCHAR(100) NOT NULL, server_name VARCHAR(100) NOT NULL, UNIQUE KEY uk_group_server (group_name, server_name)) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4`); } catch {}
}

async function seedTemplates(db) {
  const [rows] = await db.execute('SELECT COUNT(*) as c FROM email_templates');
  if (rows[0].c > 0) return;

  const temps = [
    ['verify_email', '邮箱验证', '【{{site_name}}】请验证您的邮箱',
     '<p>您好 <strong>{{username}}</strong>（游戏名: {{game_name}}，UID: {{game_uid}}），</p><p>感谢注册！请点击以下链接验证邮箱：</p><p><a href="{{verify_link}}">{{verify_link}}</a></p><p>链接有效期24小时。</p><p>— {{site_name}}</p>',
     '变量: {{site_name}}, {{username}}, {{game_name}}, {{game_uid}}, {{verify_link}}'],
    ['email_code', '邮箱验证码', '【{{site_name}}】您的邮箱验证码',
     '<p>您好，</p><p>您的邮箱验证码为：</p><p style="font-size:24px;font-weight:bold;letter-spacing:4px">{{code}}</p><p>验证码10分钟内有效。如非本人操作，请忽略此邮件。</p><p>— {{site_name}}</p>',
     '变量: {{site_name}}, {{code}}'],
    ['ticket_created', '工单创建通知', '【{{site_name}}】{{ticket_type}}已提交 #{{ticket_id}}',
     '<p><strong>{{reporter_game_name}}</strong>（UID: {{reporter_game_uid}}），您的{{ticket_type}}已提交。</p><p>工单编号: <strong>#{{ticket_id}}</strong></p><p>标题: {{ticket_title}}</p><p><a href="{{tracking_link}}">查看工单</a></p><p>— {{site_name}}</p>',
     '变量: {{site_name}}, {{reporter_game_name}}, {{ticket_type}}, {{ticket_id}}, {{ticket_title}}, {{tracking_link}}'],
    ['ticket_updated', '工单状态更新', '【{{site_name}}】工单 #{{ticket_id}} 状态更新',
     '<p>工单 <strong>#{{ticket_id}}</strong> 状态已更新为 <strong>{{ticket_status}}</strong>。</p><p>标题: {{ticket_title}}</p><p><a href="{{tracking_link}}">查看详情</a></p><p>— {{site_name}}</p>',
     '变量: {{site_name}}, {{ticket_id}}, {{ticket_title}}, {{ticket_status}}, {{tracking_link}}'],
    ['ticket_claimed', '工单被认领', '【{{site_name}}】工单 #{{ticket_id}} 已被认领',
     '<p>工单 <strong>#{{ticket_id}}</strong>（{{ticket_title}}）已被 <strong>{{assigned_to}}</strong> 认领。</p><p>— {{site_name}}</p>',
     '变量: {{site_name}}, {{ticket_id}}, {{ticket_title}}, {{assigned_to}}'],
    ['ticket_transferred', '工单已转交', '【{{site_name}}】工单 #{{ticket_id}} 已转交',
     '<p>工单 <strong>#{{ticket_id}}</strong>（{{ticket_title}}）已由 {{from_user}} 转交给 {{to_user}}。</p><p>— {{site_name}}</p>',
     '变量: {{site_name}}, {{ticket_id}}, {{ticket_title}}, {{from_user}}, {{to_user}}'],
    ['reset_password', '密码重置', '【{{site_name}}】密码重置请求',
     '<p>您好 <strong>{{username}}</strong>，</p><p>我们收到了您的密码重置请求。请点击以下链接设置新密码：</p><p><a href="{{reset_link}}">{{reset_link}}</a></p><p>链接1小时内有效。如非本人操作，请忽略此邮件。</p><p>— {{site_name}}</p>',
     '变量: {{site_name}}, {{username}}, {{reset_link}}'],
  ];

  for (const t of temps) {
    await db.execute('INSERT INTO email_templates(code, name, subject, body, description) VALUES (?,?,?,?,?)', t);
  }
}

module.exports = { getPool, query, getRow, initSchema, isInstalled, getConfig, saveConfig, CONFIG_PATH };