package sms_scheduler

import (
	"fmt"
	"go-admin/app/admin/models/bus_models"
	"go-admin/common/database"
	"go-admin/common/redisx"
	"golang.org/x/net/context"
	"log"
	"math/rand"
	"sync"
	"time"

	"gorm.io/gorm"
)

var db *gorm.DB // 需要先初始化你的 GORM DB

const (
	maxRetry       = 3
	workerPoolSize = 5
)

func ProcessPendingBatches() {
	log.Println("📡 [Scheduler] 扫描待发送批次...")
	db = database.Db
	batches := fetchPendingBatches()
	if len(batches) == 0 {
		log.Println("ℹ️ 无待发批次")
		return
	}

	wg := sync.WaitGroup{}
	sem := make(chan struct{}, workerPoolSize)

	for _, batch := range batches {
		wg.Add(1)
		sem <- struct{}{} // 限制并发

		go func(batch bus_models.SmsTaskBatch) {
			defer wg.Done()
			defer func() { <-sem }()

			err := lockAndProcessBatch(batch)
			if err != nil {
				log.Printf("❌ 批次处理失败: batch_id=%s, err=%v\n", batch.BatchID, err)
			}
		}(batch)
	}

	wg.Wait()
}

func fetchPendingBatches() []bus_models.SmsTaskBatch {
	var batches []bus_models.SmsTaskBatch
	db.Where("status = ? AND (schedule_time IS NULL OR schedule_time <= ?)", 0, time.Now()).
		Limit(10).
		Find(&batches)
	return batches
}

func lockAndProcessBatch(batch bus_models.SmsTaskBatch) error {
	tx := db.Begin()
	defer func() {
		if r := recover(); r != nil {
			tx.Rollback()
		}
	}()

	// 锁定批次
	res := tx.Model(&bus_models.SmsTaskBatch{}).
		Where("id = ? AND status = 0", batch.ID).
		Update("status", 1) // 标记发送中

	if res.RowsAffected == 0 {
		tx.Rollback()
		return nil // 已被其他任务抢占
	}

	tx.Commit()
	log.Printf("🚀 开始处理批次：batch_id=%s\n", batch.BatchID)

	err := processBatchPhones(batch)
	if err != nil {
		// 更新失败状态
		db.Model(&bus_models.SmsTaskBatch{}).Where("id = ?", batch.ID).Update("status", 3)
		return err
	}

	// 更新成功状态
	db.Model(&bus_models.SmsTaskBatch{}).Where("id = ?", batch.ID).Update("status", 1)
	updateTaskStatusIfFinished(batch.TaskID)
	return nil
}

func processBatchPhones(batch bus_models.SmsTaskBatch) error {
	ctx := context.Background()
	importID := batch.ImportID
	num := batch.Num

	key := fmt.Sprintf("sms:import:%s:%d", importID, num)
	phones, err := redisx.Client.LRange(ctx, key, 0, -1).Result()
	if err != nil {
		log.Printf("❌ 获取手机号缓存失败：%v\n", err)
		return err
	}
	if len(phones) == 0 {
		log.Printf("⚠️ 无手机号可处理，import_id=%s, num=%d\n", importID, num)
		return nil
	}

	var recordsToInsert []bus_models.SmsSendRecord

	for _, phone := range phones {
		// 避免重复发送：判断该手机号是否已存在记录
		var count int64
		db.Model(&bus_models.SmsSendRecord{}).
			Where("batch_id = ? AND phone = ?", batch.BatchID, phone).
			Count(&count)
		if count > 0 {
			continue
		}

		// 实际发送短信
		success := sendSms(phone, batch.SmsContent)
		status := 1 // 成功
		if !success {
			status = 2 // 失败
		}

		record := bus_models.SmsSendRecord{
			CooperativeNumber: batch.CooperativeNumber,
			CooperativeName:   batch.CooperativeName,
			TaskID:            batch.TaskID,
			TaskBatchID:       batch.ID,
			Phone:             phone,
			BatchID:           batch.BatchID,
			SmsContent:        batch.SmsContent,
			Status:            status,
		}
		recordsToInsert = append(recordsToInsert, record)

		log.Printf("📨 发送短信：%s，状态=%d\n", phone, status)
	}

	// 批量插入发送记录
	if len(recordsToInsert) > 0 {
		if err := db.Create(&recordsToInsert).Error; err != nil {
			log.Printf("❌ 批量写入发送记录失败：%v\n", err)
			return err
		}
	}

	return nil
}

func updateTaskStatusIfFinished(taskID uint64) {
	var pendingCount int64
	db.Model(&bus_models.SmsTaskBatch{}).
		Where("task_id = ? AND status = 0", taskID).
		Count(&pendingCount)

	if pendingCount > 0 {
		return // 尚有批次未完成，直接返回
	}

	// 统计该任务所有失败短信数（status = 2）
	var failCount int64
	db.Model(&bus_models.SmsSendRecord{}).
		Where("task_id = ? AND status = 2", taskID).
		Count(&failCount)

	// 更新任务状态为已完成，并记录失败条数
	db.Model(&bus_models.SmsTask{}).
		Where("id = ?", taskID).
		Updates(map[string]interface{}{
			"status":             2,
			"channel_fail_count": failCount,
		})

	log.Printf("🎉 任务 task_id=%d 已全部完成！失败短信总数=%d\n", taskID, failCount)
}

// 模拟发送逻辑（生产环境接通短信通道）
func sendSms(phone, content string) bool {
	// 可接入真实短信发送SDK
	time.Sleep(10 * time.Millisecond)
	return rand.Intn(4) != 0 // 25% 失败
}