package main

import (
	"crypto/rand"
	"database/sql"
	"encoding/hex"
	"log"
	"strings"

	_ "modernc.org/sqlite"
)

var DB *sql.DB

// ===== 全局配置表（A表）=====
type GlobalConfig struct {
	ID                int    `json:"id"`
	ServerAddr        string `json:"serverAddr"`
	ServerPort        int    `json:"serverPort"`
	Token             string `json:"token"`
	LogLevel          string `json:"logLevel"`
	LogMaxDays        int    `json:"logMaxDays"`
	TcpMux            bool   `json:"tcpMux"`
	TcpMuxKeepalive   int    `json:"tcpMuxKeepalive"`
	HeartbeatInterval int    `json:"heartbeatInterval"`
	HeartbeatTimeout  int    `json:"heartbeatTimeout"`
	PoolCount         int    `json:"poolCount"`
	WireProtocolV2    bool   `json:"wireProtocolV2"` // frp v2 协议开关 (v2.0 启用)
}

// ===== 隧道表（B表）=====
type Proxy struct {
	ID         int    `json:"id"`
	Name       string `json:"name"`
	Type       string `json:"type"`
	LocalIP    string `json:"localIP"`
	LocalPort  int    `json:"localPort"`
	RemotePort int    `json:"remotePort"`
	Enabled    bool   `json:"enabled"`
}

// ===== 用户表（C表）=====
type User struct {
	ID           int    `json:"id"`
	Username     string `json:"username"`
	PasswordHash string `json:"-"`
	CreatedAt    string `json:"createdAt"`
}

// ============================================================
// 数据库初始化
// ============================================================

func InitDB() error {
	var err error
	DB, err = sql.Open("sqlite", "./frpc-console.db")
	if err != nil {
		return err
	}

	// ---- 用户表 ----
	_, err = DB.Exec(`
        CREATE TABLE IF NOT EXISTS users (
            id INTEGER PRIMARY KEY AUTOINCREMENT,
            username TEXT UNIQUE NOT NULL,
            password_hash TEXT NOT NULL,
            created_at DATETIME DEFAULT CURRENT_TIMESTAMP,
            updated_at DATETIME DEFAULT CURRENT_TIMESTAMP
        )
    `)
	if err != nil {
		return err
	}

	// ---- 全局配置表 ----
	_, err = DB.Exec(`
        CREATE TABLE IF NOT EXISTS global_config (
            id INTEGER PRIMARY KEY CHECK (id = 1),
            server_addr TEXT NOT NULL DEFAULT 'frp.example.com',
            server_port INTEGER NOT NULL DEFAULT 7000,
            token TEXT NOT NULL DEFAULT 'CHANGE_ME',
            log_level TEXT NOT NULL DEFAULT 'info',
            log_max_days INTEGER NOT NULL DEFAULT 3,
            tcp_mux INTEGER NOT NULL DEFAULT 1,
            tcp_mux_keepalive INTEGER NOT NULL DEFAULT 30,
            heartbeat_interval INTEGER NOT NULL DEFAULT 15,
            heartbeat_timeout INTEGER NOT NULL DEFAULT 70,
            pool_count INTEGER NOT NULL DEFAULT 8,
            wire_protocol_v2 INTEGER NOT NULL DEFAULT 0,
            updated_at DATETIME DEFAULT CURRENT_TIMESTAMP
        )
    `)
	if err != nil {
		return err
	}

	// ---- 迁移：自动补全缺失的字段 ----
	if err := migrateGlobalConfigTable(); err != nil {
		log.Printf("⚠️  迁移警告: %v", err)
	}

	// ---- 初始化默认配置（仅当表为空时） ----
	var count int
	DB.QueryRow("SELECT COUNT(*) FROM global_config").Scan(&count)
	if count == 0 {
		_, err = DB.Exec(`
            INSERT INTO global_config (
                id, server_addr, server_port, token, log_level, log_max_days,
                tcp_mux, tcp_mux_keepalive, heartbeat_interval, heartbeat_timeout, pool_count,
                wire_protocol_v2
            ) VALUES (1, 'frp.example.com', 7000, 'CHANGE_ME', 'info', 3, 1, 30, 15, 70, 8, 0)
        `)
		if err != nil {
			return err
		}
		log.Println("✅ 全局配置初始化完成")
	}

	// ---- 隧道表 ----
	_, err = DB.Exec(`
        CREATE TABLE IF NOT EXISTS proxies (
            id INTEGER PRIMARY KEY AUTOINCREMENT,
            name TEXT UNIQUE NOT NULL,
            type TEXT NOT NULL DEFAULT 'tcp',
            local_ip TEXT NOT NULL,
            local_port INTEGER NOT NULL,
            remote_port INTEGER NOT NULL,
            enabled INTEGER NOT NULL DEFAULT 1,
            created_at DATETIME DEFAULT CURRENT_TIMESTAMP,
            updated_at DATETIME DEFAULT CURRENT_TIMESTAMP
        )
    `)
	if err != nil {
		return err
	}

	// ---- 应用配置表 ----
	_, err = DB.Exec(`
        CREATE TABLE IF NOT EXISTS app_config (
            key TEXT PRIMARY KEY,
            value TEXT NOT NULL,
            updated_at DATETIME DEFAULT CURRENT_TIMESTAMP
        )
    `)
	if err != nil {
		return err
	}

	if err := ensureJwtSecret(); err != nil {
		return err
	}

	log.Println("✅ 数据库初始化完成")
	return nil
}

// ============================================================
// Schema 迁移：自动补全缺失的字段
// ============================================================

// expectedColumns 定义所有期望的列，格式: 列名 => 完整定义
// 新增字段时，在这里加一行即可
var expectedColumns = map[string]string{
	"id":                 "id INTEGER PRIMARY KEY CHECK (id = 1)",
	"server_addr":        "server_addr TEXT NOT NULL DEFAULT 'frp.example.com'",
	"server_port":        "server_port INTEGER NOT NULL DEFAULT 7000",
	"token":              "token TEXT NOT NULL DEFAULT 'CHANGE_ME'",
	"log_level":          "log_level TEXT NOT NULL DEFAULT 'info'",
	"log_max_days":       "log_max_days INTEGER NOT NULL DEFAULT 3",
	"tcp_mux":            "tcp_mux INTEGER NOT NULL DEFAULT 1",
	"tcp_mux_keepalive":  "tcp_mux_keepalive INTEGER NOT NULL DEFAULT 30",
	"heartbeat_interval": "heartbeat_interval INTEGER NOT NULL DEFAULT 15",
	"heartbeat_timeout":  "heartbeat_timeout INTEGER NOT NULL DEFAULT 70",
	"pool_count":         "pool_count INTEGER NOT NULL DEFAULT 8",
	"wire_protocol_v2":   "wire_protocol_v2 INTEGER NOT NULL DEFAULT 0", // v1.5 新增
	"updated_at":         "updated_at DATETIME DEFAULT CURRENT_TIMESTAMP",
}

func migrateGlobalConfigTable() error {
	// 1. 获取当前表的列名
	currentCols, err := getCurrentColumns("global_config")
	if err != nil {
		return err
	}

	// 2. 比对并补全缺失的列
	var added []string
	for colName, colDef := range expectedColumns {
		if !contains(currentCols, colName) {
			alterSQL := "ALTER TABLE global_config ADD COLUMN " + colDef
			if _, err := DB.Exec(alterSQL); err != nil {
				log.Printf("⚠️  添加列 %s 失败: %v", colName, err)
				continue
			}
			added = append(added, colName)
		}
	}

	if len(added) > 0 {
		log.Printf("✅ 数据库迁移完成，新增字段: %v", added)
	} else {
		log.Println("✅ 数据库 Schema 已是最新")
	}

	return nil
}

// getCurrentColumns 查询指定表的所有列名
func getCurrentColumns(tableName string) ([]string, error) {
	rows, err := DB.Query("PRAGMA table_info(" + tableName + ")")
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	var cols []string
	for rows.Next() {
		var (
			cid     int
			name    string
			typ     string
			notNull int
			dfltVal sql.NullString
			pk      int
		)
		if err := rows.Scan(&cid, &name, &typ, &notNull, &dfltVal, &pk); err != nil {
			return nil, err
		}
		cols = append(cols, name)
	}
	return cols, rows.Err()
}

func contains(slice []string, item string) bool {
	for _, s := range slice {
		if strings.EqualFold(s, item) {
			return true
		}
	}
	return false
}

// ============================================================
// JWT 密钥管理
// ============================================================

func ensureJwtSecret() error {
	var value string
	err := DB.QueryRow("SELECT value FROM app_config WHERE key = 'jwt_secret'").Scan(&value)
	if err == nil && value != "" {
		return nil
	}

	bytes := make([]byte, 32)
	if _, err := rand.Read(bytes); err != nil {
		return err
	}
	secret := hex.EncodeToString(bytes)

	_, err = DB.Exec(`
        INSERT INTO app_config (key, value) VALUES ('jwt_secret', ?)
    `, secret)
	if err != nil {
		return err
	}
	log.Printf("✅ JWT 密钥已生成并保存到数据库")
	return nil
}

func GetJwtSecret() (string, error) {
	var secret string
	err := DB.QueryRow("SELECT value FROM app_config WHERE key = 'jwt_secret'").Scan(&secret)
	if err != nil {
		return "", err
	}
	return secret, nil
}

// ============================================================
// 全局配置 CRUD
// ============================================================

func GetGlobalConfig() (*GlobalConfig, error) {
	var cfg GlobalConfig
	err := DB.QueryRow(`
        SELECT id, server_addr, server_port, token, log_level, log_max_days,
               tcp_mux, tcp_mux_keepalive, heartbeat_interval, heartbeat_timeout, pool_count,
               wire_protocol_v2
        FROM global_config WHERE id = 1
    `).Scan(
		&cfg.ID, &cfg.ServerAddr, &cfg.ServerPort, &cfg.Token,
		&cfg.LogLevel, &cfg.LogMaxDays, &cfg.TcpMux, &cfg.TcpMuxKeepalive,
		&cfg.HeartbeatInterval, &cfg.HeartbeatTimeout, &cfg.PoolCount,
		&cfg.WireProtocolV2,
	)
	if err != nil {
		return nil, err
	}
	cfg.TcpMux = true
	return &cfg, nil
}

func UpdateGlobalConfig(cfg *GlobalConfig) error {
	_, err := DB.Exec(`
        UPDATE global_config SET
            server_addr = ?, server_port = ?, token = ?, log_level = ?, log_max_days = ?,
            tcp_mux = 1,
            tcp_mux_keepalive = ?, heartbeat_interval = ?, heartbeat_timeout = ?, pool_count = ?,
            wire_protocol_v2 = ?,
            updated_at = CURRENT_TIMESTAMP
        WHERE id = 1
    `, cfg.ServerAddr, cfg.ServerPort, cfg.Token, cfg.LogLevel, cfg.LogMaxDays,
		cfg.TcpMuxKeepalive, cfg.HeartbeatInterval, cfg.HeartbeatTimeout, cfg.PoolCount,
		cfg.WireProtocolV2)
	return err
}

// ============================================================
// 隧道 CRUD
// ============================================================

func GetProxies() ([]Proxy, error) {
	rows, err := DB.Query(`
        SELECT id, name, type, local_ip, local_port, remote_port, enabled
        FROM proxies ORDER BY id
    `)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	var proxies []Proxy
	for rows.Next() {
		var p Proxy
		err := rows.Scan(&p.ID, &p.Name, &p.Type, &p.LocalIP, &p.LocalPort, &p.RemotePort, &p.Enabled)
		if err != nil {
			return nil, err
		}
		proxies = append(proxies, p)
	}
	if err = rows.Err(); err != nil {
		return nil, err
	}
	return proxies, nil
}

func GetProxy(id int) (*Proxy, error) {
	var p Proxy
	err := DB.QueryRow(`
        SELECT id, name, type, local_ip, local_port, remote_port, enabled
        FROM proxies WHERE id = ?
    `, id).Scan(&p.ID, &p.Name, &p.Type, &p.LocalIP, &p.LocalPort, &p.RemotePort, &p.Enabled)
	if err != nil {
		return nil, err
	}
	return &p, nil
}

func CreateProxy(p *Proxy) error {
	result, err := DB.Exec(`
        INSERT INTO proxies (name, type, local_ip, local_port, remote_port, enabled)
        VALUES (?, ?, ?, ?, ?, ?)
    `, p.Name, p.Type, p.LocalIP, p.LocalPort, p.RemotePort, p.Enabled)
	if err != nil {
		return err
	}
	id, _ := result.LastInsertId()
	p.ID = int(id)
	return nil
}

func UpdateProxy(p *Proxy) error {
	_, err := DB.Exec(`
        UPDATE proxies SET
            name = ?, type = ?, local_ip = ?, local_port = ?, remote_port = ?, enabled = ?,
            updated_at = CURRENT_TIMESTAMP
        WHERE id = ?
    `, p.Name, p.Type, p.LocalIP, p.LocalPort, p.RemotePort, p.Enabled, p.ID)
	return err
}

func DeleteProxy(id int) error {
	_, err := DB.Exec("DELETE FROM proxies WHERE id = ?", id)
	return err
}

// ============================================================
// 用户 CRUD
// ============================================================

func GetUserByUsername(username string) (*User, error) {
	var u User
	err := DB.QueryRow(`
        SELECT id, username, password_hash, created_at
        FROM users WHERE username = ?
    `, username).Scan(&u.ID, &u.Username, &u.PasswordHash, &u.CreatedAt)
	if err != nil {
		return nil, err
	}
	return &u, nil
}

func CreateUser(username, passwordHash string) error {
	_, err := DB.Exec(`
        INSERT INTO users (username, password_hash) VALUES (?, ?)
    `, username, passwordHash)
	return err
}

func UpdatePassword(username, passwordHash string) error {
	_, err := DB.Exec(`
        UPDATE users SET password_hash = ?, updated_at = CURRENT_TIMESTAMP
        WHERE username = ?
    `, passwordHash, username)
	return err
}

func CountUsers() (int, error) {
	var count int
	err := DB.QueryRow("SELECT COUNT(*) FROM users").Scan(&count)
	return count, err
}