package timesync

import (
	"context"
	"encoding/json"
	"fmt"
	"net/http"
	"sync"
	"time"

	"go.uber.org/zap"
)

// TimeSync 时间同步器
type TimeSync struct {
	logger        *zap.Logger
	stopCh        chan struct{}
	beijingTZ     *time.Location
	lastSyncTime  time.Time
	lastSyncError error
	mu            sync.RWMutex
}

// K780TimeAPIResponse K780时间API响应结构
type K780TimeAPIResponse struct {
	Success string `json:"success"`
	Msgid   string `json:"msgid"`
	Msg     string `json:"msg"`
	Result  struct {
		Timestamp   string `json:"timestamp"`    // 时间戳（秒）
		TimestampMs string `json:"timestamp_ms"` // 时间戳（毫秒）
		Datetime1   string `json:"datetime_1"`   // 日期时间格式1
		Datetime2   string `json:"datetime_2"`   // 日期时间格式2
	} `json:"result"`
}

// NewTimeSync 创建时间同步器
func NewTimeSync(logger *zap.Logger) (*TimeSync, error) {
	// 加载北京时间时区
	beijingTZ, err := time.LoadLocation("Asia/Shanghai")
	if err != nil {
		return nil, fmt.Errorf("加载时区失败: %w", err)
	}

	return &TimeSync{
		logger:    logger,
		stopCh:    make(chan struct{}),
		beijingTZ: beijingTZ,
	}, nil
}

// syncTime 同步时间（从HTTP API获取北京时间）
func (ts *TimeSync) syncTime() error {
	// 使用K780时间API
	apiURL := "https://sapi.k780.com/?app=life.time&appkey=10003&sign=b59bc3ef6191eb9f747dd4e83c99f2a4&format=json"

	client := &http.Client{
		Timeout: 5 * time.Second,
	}

	// 创建请求，添加浏览器请求头
	req, err := http.NewRequest("GET", apiURL, nil)
	if err != nil {
		ts.mu.Lock()
		ts.lastSyncError = err
		ts.mu.Unlock()
		return fmt.Errorf("创建请求失败: %w", err)
	}

	// 添加浏览器请求头，模拟浏览器访问
	req.Header.Set("Accept", "text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.7")
	req.Header.Set("Accept-Language", "zh-CN,zh;q=0.9")
	req.Header.Set("Cache-Control", "max-age=0")
	req.Header.Set("Connection", "keep-alive")
	req.Header.Set("Referer", "https://www.nowapi.com/")
	req.Header.Set("Sec-Fetch-Dest", "document")
	req.Header.Set("Sec-Fetch-Mode", "navigate")
	req.Header.Set("Sec-Fetch-Site", "cross-site")
	req.Header.Set("Sec-Fetch-User", "?1")
	req.Header.Set("Upgrade-Insecure-Requests", "1")
	req.Header.Set("User-Agent", "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/143.0.0.0 Safari/537.36")
	req.Header.Set("sec-ch-ua", `"Google Chrome";v="143", "Chromium";v="143", "Not A(Brand";v="24"`)
	req.Header.Set("sec-ch-ua-mobile", "?0")
	req.Header.Set("sec-ch-ua-platform", `"macOS"`)

	resp, err := client.Do(req)
	if err != nil {
		ts.mu.Lock()
		ts.lastSyncError = err
		ts.mu.Unlock()
		return fmt.Errorf("API请求失败: %w", err)
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		err := fmt.Errorf("API返回状态码: %d", resp.StatusCode)
		ts.mu.Lock()
		ts.lastSyncError = err
		ts.mu.Unlock()
		return err
	}

	var result K780TimeAPIResponse
	if err := json.NewDecoder(resp.Body).Decode(&result); err != nil {
		ts.mu.Lock()
		ts.lastSyncError = err
		ts.mu.Unlock()
		return fmt.Errorf("解析API响应失败: %w", err)
	}

	// 检查返回状态
	if result.Success != "1" {
		errMsg := fmt.Sprintf("API返回失败状态: success=%s", result.Success)
		if result.Msg != "" {
			errMsg += fmt.Sprintf(", msg=%s", result.Msg)
		}
		if result.Msgid != "" {
			errMsg += fmt.Sprintf(", msgid=%s", result.Msgid)
		}
		err := fmt.Errorf(errMsg)
		ts.mu.Lock()
		ts.lastSyncError = err
		ts.mu.Unlock()
		ts.logger.Warn("时间API返回失败", zap.String("success", result.Success), zap.String("msgid", result.Msgid), zap.String("msg", result.Msg))
		return err
	}

	// 从result.timestamp字段解析时间戳字符串
	if result.Result.Timestamp == "" {
		err := fmt.Errorf("API返回的时间戳为空")
		ts.mu.Lock()
		ts.lastSyncError = err
		ts.mu.Unlock()
		return err
	}

	// 解析时间戳字符串为int64
	var timestamp int64
	if _, err := fmt.Sscanf(result.Result.Timestamp, "%d", &timestamp); err != nil {
		err := fmt.Errorf("解析时间戳失败: %w", err)
		ts.mu.Lock()
		ts.lastSyncError = err
		ts.mu.Unlock()
		return err
	}

	// 使用时间戳转换为北京时间
	beijingTime := time.Unix(timestamp, 0).In(ts.beijingTZ)

	// 计算时间差
	localTime := time.Now()
	timeDiff := beijingTime.Sub(localTime)

	ts.mu.Lock()
	ts.lastSyncTime = beijingTime
	ts.lastSyncError = nil
	ts.mu.Unlock()

	ts.logger.Info("时间同步成功",
		zap.String("api", apiURL),
		zap.String("remote_time", beijingTime.Format("2006-01-02 15:04:05")),
		zap.String("local_time", localTime.Format("2006-01-02 15:04:05")),
		zap.Duration("time_diff", timeDiff),
		zap.Int64("timestamp", timestamp))

	return nil
}

// Start 启动定期时间同步
func (ts *TimeSync) Start(ctx context.Context, interval time.Duration) {
	// 立即同步一次
	if err := ts.syncTime(); err != nil {
		ts.logger.Warn("初始时间同步失败", zap.Error(err))
	}

	// 定期同步
	ticker := time.NewTicker(interval)
	defer ticker.Stop()

	for {
		select {
		case <-ctx.Done():
			return
		case <-ts.stopCh:
			return
		case <-ticker.C:
			if err := ts.syncTime(); err != nil {
				ts.logger.Warn("时间同步失败", zap.Error(err))
			}
		}
	}
}

// Stop 停止时间同步
func (ts *TimeSync) Stop() {
	close(ts.stopCh)
}

// GetBeijingTime 获取当前北京时间
func (ts *TimeSync) GetBeijingTime() time.Time {
	return time.Now().In(ts.beijingTZ)
}

// GetLocation 获取北京时区
func (ts *TimeSync) GetLocation() *time.Location {
	return ts.beijingTZ
}

// GetLastSyncTime 获取最后一次同步的时间
func (ts *TimeSync) GetLastSyncTime() time.Time {
	ts.mu.RLock()
	defer ts.mu.RUnlock()
	return ts.lastSyncTime
}

// GetLastSyncError 获取最后一次同步的错误
func (ts *TimeSync) GetLastSyncError() error {
	ts.mu.RLock()
	defer ts.mu.RUnlock()
	return ts.lastSyncError
}