package service

import (
	"context"
	"errors"
	"fmt"
	"time"

	"model-gateway/dao"
	"model-gateway/model/dto"
	"model-gateway/model/entity"

	"github.com/gogf/gf/v2/database/gdb"
	"github.com/gogf/gf/v2/frame/g"
	"github.com/gogf/gf/v2/os/gtime"
	"github.com/google/uuid"
)

var Task = &taskService{}

type taskService struct{}

func (s *taskService) Create(ctx context.Context, req *dto.CreateTaskReq) (res *dto.CreateTaskRes, err error) {
	fmt.Printf("打印请求:%+v", req)
	startAt := time.Now()
	// 固化 token/user 等信息
	ctx = asyncCtx(ctx)

	// 1) 检查模型配置
	m, err := dao.Model.GetByModelName(ctx, req.ModelName)
	if err != nil {
		return nil, err
	}
	if m == nil || (m.Enabled != nil && *m.Enabled != 1) {
		return nil, errors.New("模型不存在或未启用")
	}

	taskID := uuid.NewString()
	// 2) 排队上限（严格控制：Redis 原子闸门）
	limit := GetRuntimeQueueLimit(ctx, req.ModelName, m.QueueLimit)
	if limit > 0 {
		ok, err := AcquireQueueSlot(ctx, req.ModelName, taskID, limit, m.ExpectedSeconds)
		if err != nil {
			return nil, err
		}
		if !ok {
			return nil, errors.New("任务排队已满，请稍后再试")
		}
	}

	// 将调用模型的 payload 与透传头信息一起存入 request_payload，供后台 worker 使用
	storedPayload := map[string]any{
		"payload": req.RequestPayload,
		"headers": forwardHeaders(ctx),
	}

	t := &entity.AsynchTask{
		ModelName:      req.ModelName,
		TaskID:         taskID,
		State:          0,
		BizName:        req.BizName,
		CallbackURL:    req.CallbackUrl,
		ModelKey:       m.ApiKey,
		InputRef:       req.InputRef,
		RequestPayload: storedPayload,
		EpicycleId:     req.EpicycleId,
	}
	_, err = dao.Task.Insert(ctx, t)
	if err != nil {
		// 入库失败：回滚闸门占位
		ReleaseQueueSlot(ctx, req.ModelName, taskID)
		return nil, err
	}

	// 3) 写操作日志（尽量不影响主流程，失败忽略）
	ip := ""
	ua := ""
	apiPath := "/task/createTask"
	httpMethod := "POST"
	if r := g.RequestFromCtx(ctx); r != nil {
		ip = r.GetClientIp()
		ua = r.UserAgent()
		apiPath = r.URL.Path
		httpMethod = r.Method
	}
	_, _ = dao.OpLog.Insert(ctx, &entity.LogsModelOp{
		IP:             ip,
		UserAgent:      ua,
		APIPath:        apiPath,
		HttpMethod:     httpMethod,
		BizName:        req.BizName,
		ModelName:      req.ModelName,
		TaskID:         taskID,
		OpType:         "createTask",
		Success:        1,
		ErrorMsg:       "",
		CostMs:         time.Since(startAt).Milliseconds(),
		RequestPayload: storedPayload,
		ResponsePayload: gdb.Map{
			"taskId": taskID,
		},
	})

	// 4) 创建成功后立即异步尝试执行当前任务，并仅在任务仍处于 pending(state=0) 时做定向轮询。
	// 一旦任务进入 running/success/failed/downloaded，就停止轮询，避免一直空转。
	go s.pollAndRunUntilPicked(context.WithoutCancel(ctx), taskID, req.EpicycleId)

	return &dto.CreateTaskRes{TaskID: taskID}, nil
}

// pollAndRunUntilPicked 用于 createTask 创建后的“轻量级定向轮询”：
// - 目标：尽快把刚创建的任务拉起来执行
// - 只在任务仍为 pending(state=0) 时继续尝试抢占
// - 一旦任务进入 running(1) / success(2) / failed(3) / downloaded(4)，立即停止
// - 这样不会无限轮询；runWork 仍负责处理积压队列和未处理到的任务
func (s *taskService) pollAndRunUntilPicked(ctx context.Context, taskID string, epicycleId int64) {
	if taskID == "" {
		return
	}
	interval := g.Cfg().MustGet(ctx, "asynch.worker.intervalSeconds").Int()
	if interval <= 0 {
		interval = 5
	}
	g.Log().Infof(ctx, "[task-auto-run][start] taskId=%s interval=%ds", taskID, interval)

	ticker := time.NewTicker(time.Duration(interval) * time.Second)
	defer ticker.Stop()

	tryRun := func() bool {
		t, err := dao.Task.GetByTaskID(ctx, taskID)
		if err != nil {
			g.Log().Warningf(ctx, "[task-auto-run][stop] taskId=%s reason=query_failed err=%v", taskID, err)
			return true
		}
		if t == nil {
			g.Log().Warningf(ctx, "[task-auto-run][stop] taskId=%s reason=task_not_found", taskID)
			return true
		}
		switch t.State {
		case 0:
			if err := AsyncWorker.RunByTaskID(ctx, taskID, epicycleId); err != nil {
				g.Log().Warningf(ctx, "[task-auto-run][retry] taskId=%s state=0 err=%v", taskID, err)
			} else {
				g.Log().Infof(ctx, "[task-auto-run][triggered] taskId=%s state=0", taskID)
			}
			return false
		case 1:
			g.Log().Infof(ctx, "[task-auto-run][stop] taskId=%s reason=running", taskID)
			return true
		case 2, 3, 4:
			g.Log().Infof(ctx, "[task-auto-run][stop] taskId=%s reason=terminal state=%d", taskID, t.State)
			return true
		default:
			g.Log().Infof(ctx, "[task-auto-run][stop] taskId=%s reason=unknown_state state=%d", taskID, t.State)
			return true
		}
	}

	// 先立即尝试一次
	if stop := tryRun(); stop {
		return
	}

	for {
		select {
		case <-ctx.Done():
			g.Log().Infof(ctx, "[task-auto-run][stop] taskId=%s reason=context_done", taskID)
			return
		case <-ticker.C:
			if stop := tryRun(); stop {
				return
			}
		}
	}
}

func (s *taskService) GetResult(ctx context.Context, taskID string) (res *dto.GetTaskResultRes, err error) {
	t, err := dao.Task.GetByTaskID(ctx, taskID)
	if err != nil {
		return nil, err
	}
	if t == nil {
		return nil, errors.New("任务不存在")
	}
	return &dto.GetTaskResultRes{
		OssFile: t.OssFile,
		State:   t.State,
	}, nil
}

// GetBatch 批量查询任务；将成功(state=2)的任务更新为已下载(state=4)，并写入过期时间
func (s *taskService) GetBatch(ctx context.Context, req *dto.GetTaskBatchReq) (res *dto.GetTaskBatchRes, err error) {
	if req == nil || len(req.TaskIDs) == 0 {
		return &dto.GetTaskBatchRes{List: []dto.GetTaskBatchItem{}}, nil
	}
	// 1) 先查当前租户下的任务列表
	list, err := dao.Task.ListByTaskIDs(ctx, req.TaskIDs)
	if err != nil {
		return nil, err
	}

	// 2) 对成功(state=2)的任务：标记为已下载(state=4)并写入 expire_at
	now := time.Now()
	for _, t := range list {
		if t == nil {
			continue
		}
		if t.State != 2 {
			continue
		}
		// 按模型配置决定保留时间
		m, err := dao.Model.GetByModelName(ctx, t.ModelName)
		if err != nil {
			return nil, err
		}
		retainSeconds := 86400
		if m != nil && m.AutoCleanSeconds > 0 {
			retainSeconds = m.AutoCleanSeconds
		}
		expireAt := gtime.New(now.Add(time.Duration(retainSeconds) * time.Second))
		_ = dao.Task.MarkDownloadedByID(ctx, t.Id, expireAt)

		// 为了本次返回一致性，内存里也更新
		t.State = 4
		t.ExpireAt = expireAt
	}

	// 3) 组装返回
	items := make([]dto.GetTaskBatchItem, 0, len(list))
	for _, t := range list {
		if t == nil {
			continue
		}
		items = append(items, dto.GetTaskBatchItem{
			TaskID:  t.TaskID,
			State:   t.State,
			OssFile: t.OssFile,
		})
	}
	return &dto.GetTaskBatchRes{List: items}, nil
}

func (s *taskService) List(ctx context.Context, req *dto.ListTaskReq) (res *dto.ListTaskRes, err error) {
	pageNum, pageSize := 1, 10
	if req != nil {
		if req.PageNum > 0 {
			pageNum = req.PageNum
		}
		if req.PageSize > 0 {
			pageSize = req.PageSize
		}
	}
	modelName := ""
	taskID := ""
	var state *int
	if req != nil {
		modelName = req.ModelName
		taskID = req.TaskID
		state = req.State
	}
	list, total, err := dao.Task.List(ctx, pageNum, pageSize, modelName, taskID, state)
	if err != nil {
		return nil, err
	}
	return &dto.ListTaskRes{List: list, Total: total}, nil
}