package database

import (
	"database/sql"
	"fmt"
	"os"
	"path/filepath"

	"simple_portal/config"

	_ "github.com/go-sql-driver/mysql"
	_ "modernc.org/sqlite"
)

// DB is the global database connection pointer.
var DB *sql.DB

// InitDB 根据配置初始化数据库，支持 SQLite 和 MySQL
func InitDB() error {
	dbType := config.Cfg.Database.Type
	dataDir := config.Cfg.Data.Dir

	switch dbType {
	case "mysql":
		return initMySQL()
	case "sqlite":
		return initSQLite(dataDir)
	default:
		return fmt.Errorf("不支持的数据库类型: %s（可选: sqlite, mysql）", dbType)
	}
}

// initSQLite 初始化 SQLite 数据库
func initSQLite(dataDir string) error {
	dbPath := config.GetDBPath()

	// 创建数据目录
	if err := os.MkdirAll(filepath.Dir(dbPath), 0755); err != nil {
		return fmt.Errorf("创建数据目录失败: %w", err)
	}

	var err error
	DB, err = sql.Open("sqlite", dbPath)
	if err != nil {
		return fmt.Errorf("打开 SQLite 数据库失败: %w", err)
	}

	// SQLite 需要限制最大连接数为 1 以保证写安全
	DB.SetMaxOpenConns(1)

	// 启用 WAL 模式提升并发读性能
	if _, err := DB.Exec("PRAGMA journal_mode=WAL"); err != nil {
		return fmt.Errorf("设置 WAL 模式失败: %w", err)
	}

	// 创建表
	if err := createTables(); err != nil {
		return fmt.Errorf("创建数据表失败: %w", err)
	}

	// 初始化默认数据
	if err := seedData(); err != nil {
		return fmt.Errorf("初始化默认数据失败: %w", err)
	}

	return nil
}

// initMySQL 初始化 MySQL 数据库
func initMySQL() error {
	dsn := config.Cfg.Database.MySQL.GetDSN()

	var err error
	DB, err = sql.Open("mysql", dsn)
	if err != nil {
		return fmt.Errorf("打开 MySQL 数据库失败: %w", err)
	}

	// 测试连接
	if err := DB.Ping(); err != nil {
		return fmt.Errorf("连接 MySQL 失败: %w", err)
	}

	// MySQL 不限制最大连接数（使用默认池）
	DB.SetMaxOpenConns(0)

	// 创建表
	if err := createTables(); err != nil {
		return fmt.Errorf("创建数据表失败: %w", err)
	}

	// 初始化默认数据
	if err := seedData(); err != nil {
		return fmt.Errorf("初始化默认数据失败: %w", err)
	}

	return nil
}

// createTables 创建所有数据表
func createTables() error {
	_, err := DB.Exec(`
		CREATE TABLE IF NOT EXISTS cards (
			id INTEGER PRIMARY KEY AUTOINCREMENT,
			icon TEXT,
			title TEXT NOT NULL,
			subtitle TEXT,
			url TEXT NOT NULL,
			sort INTEGER DEFAULT 0,
			enabled INTEGER DEFAULT 1,
			created_at DATETIME DEFAULT CURRENT_TIMESTAMP
		);
		CREATE TABLE IF NOT EXISTS settings (
			key TEXT PRIMARY KEY,
			value TEXT
		);
		CREATE TABLE IF NOT EXISTS admins (
			id INTEGER PRIMARY KEY AUTOINCREMENT,
			username TEXT UNIQUE NOT NULL,
			password TEXT NOT NULL
		);
		CREATE TABLE IF NOT EXISTS login_logs (
			id INTEGER PRIMARY KEY AUTOINCREMENT,
			admin_id INTEGER,
			username TEXT NOT NULL,
			ip TEXT NOT NULL,
			user_agent TEXT,
			success INTEGER NOT NULL DEFAULT 0,
			created_at DATETIME DEFAULT CURRENT_TIMESTAMP
		);
		CREATE TABLE IF NOT EXISTS ip_bans (
			id INTEGER PRIMARY KEY AUTOINCREMENT,
			ip TEXT NOT NULL,
			reason TEXT,
			fail_count INTEGER DEFAULT 0,
			banned_until DATETIME NOT NULL,
			created_at DATETIME DEFAULT CURRENT_TIMESTAMP
		);
		CREATE TABLE IF NOT EXISTS ip_whitelist (
			id INTEGER PRIMARY KEY AUTOINCREMENT,
			ip TEXT NOT NULL,
			comment TEXT,
			created_at DATETIME DEFAULT CURRENT_TIMESTAMP
		);
		CREATE TABLE IF NOT EXISTS access_logs (
			id INTEGER PRIMARY KEY AUTOINCREMENT,
			ip TEXT NOT NULL,
			user_agent TEXT,
			action_type TEXT NOT NULL,
			detail TEXT DEFAULT '',
			referer TEXT DEFAULT '',
			created_at DATETIME DEFAULT CURRENT_TIMESTAMP
		);
		CREATE INDEX IF NOT EXISTS idx_access_logs_ip ON access_logs(ip);
		CREATE INDEX IF NOT EXISTS idx_access_logs_action_type ON access_logs(action_type);
		CREATE INDEX IF NOT EXISTS idx_access_logs_created_at ON access_logs(created_at);
	`)
	return err
}

// seedData 插入默认管理员和搜索引擎配置
func seedData() error {
	// 插入默认管理员
	var count int
	err := DB.QueryRow("SELECT COUNT(*) FROM admins WHERE username = ?", "admin").Scan(&count)
	if err != nil {
		return err
	}
	if count == 0 {
		_, err = DB.Exec(
			"INSERT INTO admins (username, password) VALUES (?, ?)",
			"admin",
			"$2a$10$h3Csm2HmWUtvim3MJ8VG0OHx/tevZorlUXQVDtN2EgWhROtiM3Sg.", // bcrypt hash for "admin123"
		)
		if err != nil {
			return err
		}
	}

	// 插入默认搜索引擎设置
	var settingCount int
	err = DB.QueryRow("SELECT COUNT(*) FROM settings WHERE key = ?", "search_engine").Scan(&settingCount)
	if err != nil {
		return err
	}
	if settingCount == 0 {
		_, err = DB.Exec(
			"INSERT INTO settings (key, value) VALUES (?, ?)",
			"search_engine",
			"https://www.google.com/search?q=%s",
		)
		if err != nil {
			return err
		}
	}

	// 插入默认主页设置
	defaultSettings := []struct {
		key   string
		value string
	}{
		{"homepage_title", "Portal"},
		{"homepage_subtitle", ""},
		{"homepage_background", ""},
	}
	for _, s := range defaultSettings {
		var cnt int
		err = DB.QueryRow("SELECT COUNT(*) FROM settings WHERE key = ?", s.key).Scan(&cnt)
		if err != nil {
			return err
		}
		if cnt == 0 {
			_, err = DB.Exec("INSERT INTO settings (key, value) VALUES (?, ?)", s.key, s.value)
			if err != nil {
				return err
			}
		}
	}

	return nil
}

// CloseDB 关闭数据库连接
func CloseDB() error {
	if DB != nil {
		return DB.Close()
	}
	return nil
}