package polling

import (
	"bytes"
	"context"
	"fmt"
	"net/http"
	"strings"
	"sync"
	"time"

	"github.com/bytedance/sonic"
	"github.com/redis/go-redis/v9"
	"go.uber.org/zap"

	"github.com/break/junhong_cmp_fiber/internal/model"
	"github.com/break/junhong_cmp_fiber/internal/store/postgres"
	"github.com/break/junhong_cmp_fiber/pkg/constants"
	"github.com/break/junhong_cmp_fiber/pkg/errors"
)

// AlertService 告警服务
type AlertService struct {
	ruleStore    *postgres.PollingAlertRuleStore
	historyStore *postgres.PollingAlertHistoryStore
	redis        *redis.Client
	logger       *zap.Logger
}

// NewAlertService 创建告警服务实例
func NewAlertService(
	ruleStore *postgres.PollingAlertRuleStore,
	historyStore *postgres.PollingAlertHistoryStore,
	redis *redis.Client,
	logger *zap.Logger,
) *AlertService {
	return &AlertService{
		ruleStore:    ruleStore,
		historyStore: historyStore,
		redis:        redis,
		logger:       logger,
	}
}

// CreateRule 创建告警规则
func (s *AlertService) CreateRule(ctx context.Context, rule *model.PollingAlertRule) error {
	// 验证参数
	if rule.RuleName == "" {
		return errors.New(errors.CodeInvalidParam, "规则名称不能为空")
	}
	if rule.MetricType == "" {
		return errors.New(errors.CodeInvalidParam, "指标类型不能为空")
	}
	if rule.TaskType == "" {
		return errors.New(errors.CodeInvalidParam, "任务类型不能为空")
	}

	rule.Status = 1 // 默认启用
	if rule.CooldownMinutes == 0 {
		rule.CooldownMinutes = 5 // 默认5分钟冷却期
	}
	if rule.Operator == "" {
		rule.Operator = ">" // 默认大于
	}
	return s.ruleStore.Create(ctx, rule)
}

// GetRule 获取告警规则
func (s *AlertService) GetRule(ctx context.Context, id uint) (*model.PollingAlertRule, error) {
	rule, err := s.ruleStore.GetByID(ctx, id)
	if err != nil {
		return nil, errors.Wrap(errors.CodeNotFound, err, "告警规则不存在")
	}
	return rule, nil
}

// ListRules 获取告警规则列表
func (s *AlertService) ListRules(ctx context.Context) ([]*model.PollingAlertRule, error) {
	return s.ruleStore.List(ctx)
}

// UpdateRule 更新告警规则
func (s *AlertService) UpdateRule(ctx context.Context, id uint, updates map[string]interface{}) error {
	rule, err := s.ruleStore.GetByID(ctx, id)
	if err != nil {
		return errors.Wrap(errors.CodeNotFound, err, "告警规则不存在")
	}

	if name, ok := updates["rule_name"].(string); ok && name != "" {
		rule.RuleName = name
	}
	if threshold, ok := updates["threshold"].(float64); ok {
		rule.Threshold = threshold
	}
	if level, ok := updates["alert_level"].(string); ok {
		rule.AlertLevel = level
	}
	if status, ok := updates["status"].(int); ok {
		rule.Status = int16(status)
	}
	if cooldown, ok := updates["cooldown_minutes"].(int); ok {
		rule.CooldownMinutes = cooldown
	}
	if channels, ok := updates["notification_channels"].(string); ok {
		rule.NotificationChannels = channels
	}

	return s.ruleStore.Update(ctx, rule)
}

// DeleteRule 删除告警规则
func (s *AlertService) DeleteRule(ctx context.Context, id uint) error {
	_, err := s.ruleStore.GetByID(ctx, id)
	if err != nil {
		return errors.Wrap(errors.CodeNotFound, err, "告警规则不存在")
	}
	return s.ruleStore.Delete(ctx, id)
}

// ListHistory 获取告警历史
func (s *AlertService) ListHistory(ctx context.Context, page, pageSize int, ruleID *uint) ([]*model.PollingAlertHistory, int64, error) {
	if page < 1 {
		page = 1
	}
	if pageSize < 1 || pageSize > 100 {
		pageSize = 20
	}
	return s.historyStore.List(ctx, page, pageSize, ruleID)
}

// CheckAlerts 检查告警（定时调用）
func (s *AlertService) CheckAlerts(ctx context.Context) error {
	rules, err := s.ruleStore.ListEnabled(ctx)
	if err != nil {
		return err
	}

	for _, rule := range rules {
		if err := s.checkRule(ctx, rule); err != nil {
			s.logger.Warn("检查告警规则失败",
				zap.Uint("rule_id", rule.ID),
				zap.String("rule_name", rule.RuleName),
				zap.Error(err))
		}
	}

	return nil
}

// checkRule 检查单个规则
func (s *AlertService) checkRule(ctx context.Context, rule *model.PollingAlertRule) error {
	// 检查冷却期
	if s.isInCooldown(ctx, rule) {
		return nil
	}

	// 获取当前指标值
	currentValue, err := s.getMetricValue(ctx, rule.TaskType, rule.MetricType)
	if err != nil {
		return err
	}

	// 判断是否触发告警
	triggered := false
	switch rule.Operator {
	case ">":
		triggered = currentValue > rule.Threshold
	case ">=":
		triggered = currentValue >= rule.Threshold
	case "<":
		triggered = currentValue < rule.Threshold
	case "<=":
		triggered = currentValue <= rule.Threshold
	case "==":
		triggered = currentValue == rule.Threshold
	default:
		triggered = currentValue > rule.Threshold
	}

	if triggered {
		return s.triggerAlert(ctx, rule, currentValue)
	}

	return nil
}

// isInCooldown 检查是否在冷却期
func (s *AlertService) isInCooldown(ctx context.Context, rule *model.PollingAlertRule) bool {
	if rule.CooldownMinutes <= 0 {
		return false
	}

	history, err := s.historyStore.GetLatestByRuleID(ctx, rule.ID)
	if err != nil {
		return false // 没有历史记录，不在冷却期
	}

	cooldownEnd := history.CreatedAt.Add(time.Duration(rule.CooldownMinutes) * time.Minute)
	return time.Now().Before(cooldownEnd)
}

// getMetricValue 获取指标值
func (s *AlertService) getMetricValue(ctx context.Context, taskType, metricType string) (float64, error) {
	statsKey := constants.RedisPollingStatsKey(taskType)
	data, err := s.redis.HGetAll(ctx, statsKey).Result()
	if err != nil {
		return 0, err
	}

	switch metricType {
	case "queue_size":
		// 获取队列大小
		var queueKey string
		switch taskType {
		case constants.TaskTypePollingRealname:
			queueKey = constants.RedisPollingQueueRealnameKey()
		case constants.TaskTypePollingCarddata:
			queueKey = constants.RedisPollingQueueCarddataKey()
		case constants.TaskTypePollingPackage:
			queueKey = constants.RedisPollingQueuePackageKey()
		}
		size, _ := s.redis.ZCard(ctx, queueKey).Result()
		return float64(size), nil

	case "success_rate":
		success := parseInt64(data["success_count_1h"])
		failure := parseInt64(data["failure_count_1h"])
		total := success + failure
		if total == 0 {
			return 100, nil // 无数据时认为成功率 100%
		}
		return float64(success) / float64(total) * 100, nil

	case "avg_duration":
		success := parseInt64(data["success_count_1h"])
		failure := parseInt64(data["failure_count_1h"])
		total := success + failure
		duration := parseInt64(data["total_duration_1h"])
		if total == 0 {
			return 0, nil
		}
		return float64(duration) / float64(total), nil

	case "concurrency":
		currentKey := constants.RedisPollingConcurrencyCurrentKey(taskType)
		current, _ := s.redis.Get(ctx, currentKey).Int64()
		return float64(current), nil

	default:
		return 0, errors.New(errors.CodeInvalidParam, "未知的指标类型")
	}
}

// triggerAlert 触发告警
func (s *AlertService) triggerAlert(ctx context.Context, rule *model.PollingAlertRule, currentValue float64) error {
	// 创建告警历史记录
	alertMessage := s.buildAlertMessage(rule, currentValue)
	history := &model.PollingAlertHistory{
		RuleID:               rule.ID,
		TaskType:             rule.TaskType,
		MetricType:           rule.MetricType,
		AlertLevel:           rule.AlertLevel,
		Threshold:            rule.Threshold,
		CurrentValue:         currentValue,
		AlertMessage:         alertMessage,
		NotificationChannels: rule.NotificationChannels,
		NotificationStatus:   "pending",
	}

	if err := s.historyStore.Create(ctx, history); err != nil {
		return err
	}

	s.logger.Warn("触发告警",
		zap.Uint("rule_id", rule.ID),
		zap.String("rule_name", rule.RuleName),
		zap.String("task_type", rule.TaskType),
		zap.String("metric_type", rule.MetricType),
		zap.String("level", rule.AlertLevel),
		zap.Float64("threshold", rule.Threshold),
		zap.Float64("current_value", currentValue))

	// 发送通知（邮件、短信、Webhook 等）
	s.sendNotifications(ctx, rule, history, alertMessage)

	return nil
}

// sendNotifications 发送告警通知到配置的渠道
func (s *AlertService) sendNotifications(ctx context.Context, rule *model.PollingAlertRule, history *model.PollingAlertHistory, message string) {
	channels := parseNotificationChannels(rule.NotificationChannels)
	if len(channels) == 0 {
		s.logger.Debug("未配置通知渠道，跳过通知发送", zap.Uint("rule_id", rule.ID))
		return
	}

	var wg sync.WaitGroup
	var successCount, failCount int
	var mu sync.Mutex

	for _, channel := range channels {
		wg.Add(1)
		go func(ch string) {
			defer wg.Done()
			var err error
			switch ch {
			case "email":
				err = s.sendEmailNotification(ctx, rule, message)
			case "sms":
				err = s.sendSMSNotification(ctx, rule, message)
			case "webhook":
				err = s.sendWebhookNotification(ctx, rule, history)
			default:
				s.logger.Warn("未知的通知渠道", zap.String("channel", ch))
				return
			}

			mu.Lock()
			if err != nil {
				failCount++
				s.logger.Error("发送通知失败",
					zap.String("channel", ch),
					zap.Uint("rule_id", rule.ID),
					zap.Error(err))
			} else {
				successCount++
				s.logger.Info("发送通知成功",
					zap.String("channel", ch),
					zap.Uint("rule_id", rule.ID))
			}
			mu.Unlock()
		}(channel)
	}

	wg.Wait()

	// 更新通知状态
	var status string
	if successCount > 0 && failCount == 0 {
		status = "sent"
	} else if successCount > 0 {
		status = "partial"
	} else {
		status = "failed"
	}

	if err := s.historyStore.UpdateNotificationStatus(ctx, history.ID, status); err != nil {
		s.logger.Warn("更新通知状态失败", zap.Uint("history_id", history.ID), zap.Error(err))
	}
}

// parseNotificationChannels 解析通知渠道配置
// 格式: "email,sms,webhook" 或 JSON 数组
func parseNotificationChannels(channels string) []string {
	if channels == "" {
		return nil
	}

	// 尝试解析为 JSON 数组
	var result []string
	if err := sonic.UnmarshalString(channels, &result); err == nil {
		return result
	}

	// 按逗号分割
	parts := strings.Split(channels, ",")
	result = make([]string, 0, len(parts))
	for _, p := range parts {
		p = strings.TrimSpace(p)
		if p != "" {
			result = append(result, p)
		}
	}
	return result
}

// getWebhookURLFromConfig 从配置中解析 Webhook URL
// 配置格式: {"webhook_url": "https://example.com/webhook"}
func getWebhookURLFromConfig(config string) string {
	if config == "" {
		return ""
	}
	var cfg map[string]any
	if err := sonic.UnmarshalString(config, &cfg); err != nil {
		return ""
	}
	if url, ok := cfg["webhook_url"].(string); ok {
		return url
	}
	return ""
}

// sendEmailNotification 发送邮件通知
func (s *AlertService) sendEmailNotification(_ context.Context, rule *model.PollingAlertRule, message string) error {
	// TODO: 集成邮件服务
	// 当前仅记录日志，实际发送需要配置 SMTP 服务
	s.logger.Info("邮件通知（待实现）",
		zap.Uint("rule_id", rule.ID),
		zap.String("message", message))
	return nil
}

// sendSMSNotification 发送短信通知
func (s *AlertService) sendSMSNotification(_ context.Context, rule *model.PollingAlertRule, message string) error {
	// TODO: 集成短信服务
	// 当前仅记录日志，实际发送需要配置短信网关
	s.logger.Info("短信通知（待实现）",
		zap.Uint("rule_id", rule.ID),
		zap.String("message", message))
	return nil
}

// sendWebhookNotification 发送 Webhook 通知
func (s *AlertService) sendWebhookNotification(ctx context.Context, rule *model.PollingAlertRule, history *model.PollingAlertHistory) error {
	// 从规则配置中获取 Webhook URL
	webhookURL := getWebhookURLFromConfig(rule.NotificationConfig)
	if webhookURL == "" {
		s.logger.Debug("未配置 Webhook URL，跳过发送", zap.Uint("rule_id", rule.ID))
		return nil
	}

	// 构建告警数据
	payload := map[string]any{
		"rule_id":       rule.ID,
		"rule_name":     rule.RuleName,
		"task_type":     rule.TaskType,
		"metric_type":   rule.MetricType,
		"alert_level":   rule.AlertLevel,
		"threshold":     rule.Threshold,
		"current_value": history.CurrentValue,
		"message":       history.AlertMessage,
		"triggered_at":  time.Now().Format(time.RFC3339),
	}

	jsonData, err := sonic.Marshal(payload)
	if err != nil {
		return fmt.Errorf("序列化告警数据失败: %w", err)
	}

	// 发送 HTTP POST 请求
	req, err := http.NewRequestWithContext(ctx, http.MethodPost, webhookURL, bytes.NewReader(jsonData))
	if err != nil {
		return fmt.Errorf("创建请求失败: %w", err)
	}
	req.Header.Set("Content-Type", "application/json")

	client := &http.Client{Timeout: 10 * time.Second}
	resp, err := client.Do(req)
	if err != nil {
		return fmt.Errorf("发送请求失败: %w", err)
	}
	defer resp.Body.Close()

	if resp.StatusCode < 200 || resp.StatusCode >= 300 {
		return fmt.Errorf("Webhook 返回错误状态码: %d", resp.StatusCode)
	}

	s.logger.Info("Webhook 通知发送成功",
		zap.Uint("rule_id", rule.ID),
		zap.String("url", webhookURL),
		zap.Int("status_code", resp.StatusCode))

	return nil
}

// buildAlertMessage 构建告警消息
func (s *AlertService) buildAlertMessage(rule *model.PollingAlertRule, currentValue float64) string {
	taskTypeName := s.getTaskTypeName(rule.TaskType)
	metricTypeName := s.getMetricTypeName(rule.MetricType)

	return taskTypeName + "的" + metricTypeName + "已触发告警: " +
		"当前值 " + formatFloat(currentValue) + ", 阈值 " + formatFloat(rule.Threshold)
}

func (s *AlertService) getTaskTypeName(taskType string) string {
	switch taskType {
	case constants.TaskTypePollingRealname:
		return "实名检查"
	case constants.TaskTypePollingCarddata:
		return "流量检查"
	case constants.TaskTypePollingPackage:
		return "套餐检查"
	default:
		return taskType
	}
}

func (s *AlertService) getMetricTypeName(metricType string) string {
	switch metricType {
	case "queue_size":
		return "队列积压"
	case "success_rate":
		return "成功率"
	case "avg_duration":
		return "平均耗时"
	case "concurrency":
		return "并发数"
	default:
		return metricType
	}
}

func formatFloat(f float64) string {
	// 简单格式化，保留2位小数
	return string(rune(int(f))) + "." + string(rune(int(f*100)%100))
}