package db

import (
	"database/sql"
	"encoding/json"
	"sync"
	"time"

	_ "modernc.org/sqlite"

	"github.com/gotunnel/pkg/protocol"
)

// SQLiteStore SQLite 存储实现
type SQLiteStore struct {
	db *sql.DB
	mu sync.RWMutex
}

// NewSQLiteStore 创建 SQLite 存储
func NewSQLiteStore(dbPath string) (*SQLiteStore, error) {
	db, err := sql.Open("sqlite", dbPath)
	if err != nil {
		return nil, err
	}

	s := &SQLiteStore{db: db}
	if err := s.init(); err != nil {
		db.Close()
		return nil, err
	}

	return s, nil
}

// init 初始化数据库表
func (s *SQLiteStore) init() error {
	// 创建客户端表
	_, err := s.db.Exec(`
		CREATE TABLE IF NOT EXISTS clients (
			id TEXT PRIMARY KEY,
			nickname TEXT NOT NULL DEFAULT '',
			rules TEXT NOT NULL DEFAULT '[]'
		)
	`)
	if err != nil {
		return err
	}

	// 迁移：添加 nickname 列
	s.db.Exec(`ALTER TABLE clients ADD COLUMN nickname TEXT NOT NULL DEFAULT ''`)

	// 创建流量统计表
	_, err = s.db.Exec(`
		CREATE TABLE IF NOT EXISTS traffic_stats (
			hour_ts INTEGER PRIMARY KEY,
			inbound INTEGER NOT NULL DEFAULT 0,
			outbound INTEGER NOT NULL DEFAULT 0
		)
	`)
	if err != nil {
		return err
	}

	// 创建总流量表
	_, err = s.db.Exec(`
		CREATE TABLE IF NOT EXISTS traffic_total (
			id INTEGER PRIMARY KEY CHECK (id = 1),
			inbound INTEGER NOT NULL DEFAULT 0,
			outbound INTEGER NOT NULL DEFAULT 0
		)
	`)
	if err != nil {
		return err
	}

	// 初始化总流量记录
	s.db.Exec(`INSERT OR IGNORE INTO traffic_total (id, inbound, outbound) VALUES (1, 0, 0)`)

	// 创建安装token表
	_, err = s.db.Exec(`
		CREATE TABLE IF NOT EXISTS install_tokens (
			token TEXT PRIMARY KEY,
			client_id TEXT NOT NULL,
			created_at INTEGER NOT NULL,
			used INTEGER NOT NULL DEFAULT 0
		)
	`)
	if err != nil {
		return err
	}

	return nil
}

// Close 关闭数据库连接
func (s *SQLiteStore) Close() error {
	return s.db.Close()
}

// GetAllClients 获取所有客户端
func (s *SQLiteStore) GetAllClients() ([]Client, error) {
	s.mu.RLock()
	defer s.mu.RUnlock()

	rows, err := s.db.Query(`SELECT id, nickname, rules FROM clients`)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	var clients []Client
	for rows.Next() {
		var c Client
		var rulesJSON string
		if err := rows.Scan(&c.ID, &c.Nickname, &rulesJSON); err != nil {
			return nil, err
		}
		if err := json.Unmarshal([]byte(rulesJSON), &c.Rules); err != nil {
			c.Rules = []protocol.ProxyRule{}
		}
		clients = append(clients, c)
	}
	return clients, nil
}

// GetClient 获取单个客户端
func (s *SQLiteStore) GetClient(id string) (*Client, error) {
	s.mu.RLock()
	defer s.mu.RUnlock()

	var c Client
	var rulesJSON string
	err := s.db.QueryRow(`SELECT id, nickname, rules FROM clients WHERE id = ?`, id).Scan(&c.ID, &c.Nickname, &rulesJSON)
	if err != nil {
		return nil, err
	}
	if err := json.Unmarshal([]byte(rulesJSON), &c.Rules); err != nil {
		c.Rules = []protocol.ProxyRule{}
	}
	return &c, nil
}

// CreateClient 创建客户端
func (s *SQLiteStore) CreateClient(c *Client) error {
	s.mu.Lock()
	defer s.mu.Unlock()

	rulesJSON, err := json.Marshal(c.Rules)
	if err != nil {
		return err
	}
	_, err = s.db.Exec(`INSERT INTO clients (id, nickname, rules) VALUES (?, ?, ?)`,
		c.ID, c.Nickname, string(rulesJSON))
	return err
}

// UpdateClient 更新客户端
func (s *SQLiteStore) UpdateClient(c *Client) error {
	s.mu.Lock()
	defer s.mu.Unlock()

	rulesJSON, err := json.Marshal(c.Rules)
	if err != nil {
		return err
	}
	_, err = s.db.Exec(`UPDATE clients SET nickname = ?, rules = ? WHERE id = ?`,
		c.Nickname, string(rulesJSON), c.ID)
	return err
}

// DeleteClient 删除客户端
func (s *SQLiteStore) DeleteClient(id string) error {
	s.mu.Lock()
	defer s.mu.Unlock()

	_, err := s.db.Exec(`DELETE FROM clients WHERE id = ?`, id)
	return err
}

// ClientExists 检查客户端是否存在
func (s *SQLiteStore) ClientExists(id string) (bool, error) {
	s.mu.RLock()
	defer s.mu.RUnlock()

	var count int
	err := s.db.QueryRow(`SELECT COUNT(*) FROM clients WHERE id = ?`, id).Scan(&count)
	return count > 0, err
}

// GetClientRules 获取客户端规则
func (s *SQLiteStore) GetClientRules(id string) ([]protocol.ProxyRule, error) {
	c, err := s.GetClient(id)
	if err != nil {
		return nil, err
	}
	return c.Rules, nil
}

// ========== 流量统计方法 ==========

// getHourTimestamp 获取当前小时的时间戳
func getHourTimestamp() int64 {
	now := time.Now()
	return time.Date(now.Year(), now.Month(), now.Day(), now.Hour(), 0, 0, 0, now.Location()).Unix()
}

// AddTraffic 添加流量记录
func (s *SQLiteStore) AddTraffic(inbound, outbound int64) error {
	s.mu.Lock()
	defer s.mu.Unlock()

	hourTs := getHourTimestamp()

	// 更新小时统计
	_, err := s.db.Exec(`
		INSERT INTO traffic_stats (hour_ts, inbound, outbound) VALUES (?, ?, ?)
		ON CONFLICT(hour_ts) DO UPDATE SET inbound = inbound + ?, outbound = outbound + ?
	`, hourTs, inbound, outbound, inbound, outbound)
	if err != nil {
		return err
	}

	// 更新总流量
	_, err = s.db.Exec(`
		UPDATE traffic_total SET inbound = inbound + ?, outbound = outbound + ? WHERE id = 1
	`, inbound, outbound)
	return err
}

// GetTotalTraffic 获取总流量
func (s *SQLiteStore) GetTotalTraffic() (inbound, outbound int64, err error) {
	s.mu.RLock()
	defer s.mu.RUnlock()

	err = s.db.QueryRow(`SELECT inbound, outbound FROM traffic_total WHERE id = 1`).Scan(&inbound, &outbound)
	return
}

// Get24HourTraffic 获取24小时流量
func (s *SQLiteStore) Get24HourTraffic() (inbound, outbound int64, err error) {
	s.mu.RLock()
	defer s.mu.RUnlock()

	cutoff := time.Now().Add(-24 * time.Hour).Unix()
	err = s.db.QueryRow(`
		SELECT COALESCE(SUM(inbound), 0), COALESCE(SUM(outbound), 0) 
		FROM traffic_stats WHERE hour_ts >= ?
	`, cutoff).Scan(&inbound, &outbound)
	return
}

// GetHourlyTraffic 获取每小时流量记录（始终返回完整的 hours 小时数据）
func (s *SQLiteStore) GetHourlyTraffic(hours int) ([]TrafficRecord, error) {
	s.mu.RLock()
	defer s.mu.RUnlock()

	// 计算当前小时的起始时间戳
	now := time.Now()
	currentHour := time.Date(now.Year(), now.Month(), now.Day(), now.Hour(), 0, 0, 0, now.Location())

	// 查询数据库中的记录
	cutoff := currentHour.Add(-time.Duration(hours-1) * time.Hour).Unix()
	rows, err := s.db.Query(`
		SELECT hour_ts, inbound, outbound FROM traffic_stats
		WHERE hour_ts >= ? ORDER BY hour_ts ASC
	`, cutoff)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	// 将数据库记录放入 map 以便快速查找
	dbRecords := make(map[int64]TrafficRecord)
	for rows.Next() {
		var r TrafficRecord
		if err := rows.Scan(&r.Timestamp, &r.Inbound, &r.Outbound); err != nil {
			return nil, err
		}
		dbRecords[r.Timestamp] = r
	}

	// 生成完整的 hours 小时数据
	records := make([]TrafficRecord, hours)
	for i := 0; i < hours; i++ {
		ts := currentHour.Add(-time.Duration(hours-1-i) * time.Hour).Unix()
		if r, ok := dbRecords[ts]; ok {
			records[i] = r
		} else {
			records[i] = TrafficRecord{Timestamp: ts, Inbound: 0, Outbound: 0}
		}
	}

	return records, nil
}