package router

import (
	"encoding/json"
	"fmt"
	"net/http"
	"strconv"
	"time"

	"bilidown/internal/task"
	"bilidown/internal/util"
)

func createTask(w http.ResponseWriter, r *http.Request) {
	defer r.Body.Close()
	if r.Method != http.MethodPost {
		util.Res{Success: false, Message: "不支持的请求方法"}.Write(w)
		return
	}
	var body []task.TaskInDB
	err := json.NewDecoder(r.Body).Decode(&body)
	if err != nil {
		util.Res{Success: false, Message: "参数错误"}.Write(w)
		return
	}

	if len(body) == 0 {
		util.Res{Success: false, Message: "任务列表为空"}.Write(w)
		return
	}

	db := util.MustGetDB()
	defer db.Close()

	// 预先获取下载目录
	folder, err := util.GetCurrentFolder(db)
	if err != nil {
		util.Res{Success: false, Message: fmt.Sprintf("获取下载目录失败: %v", err)}.Write(w)
		return
	}

	// 批量验证参数
	for _, item := range body {
		if !util.CheckBvidFormat(item.Bvid) {
			util.Res{Success: false, Message: fmt.Sprintf("bvid 格式错误: %s", item.Bvid)}.Write(w)
			return
		}
		if item.Title == "" || item.Owner == "" {
			util.Res{Success: false, Message: "标题或作者为空"}.Write(w)
			return
		}
	}

	// 批量数据库插入（单事务）
	tx, err := db.Begin()
	if err != nil {
		util.Res{Success: false, Message: fmt.Sprintf("开启事务失败: %v", err)}.Write(w)
		return
	}

	stmt, err := tx.Prepare(`INSERT INTO "task" ("bvid", "cid", "format", "title", "owner", "cover", "status", "folder", "duration", "download_type")
		VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?)`)
	if err != nil {
		tx.Rollback()
		util.Res{Success: false, Message: fmt.Sprintf("准备语句失败: %v", err)}.Write(w)
		return
	}
	defer stmt.Close()

	tasks := make([]*task.Task, 0, len(body))
	for _, item := range body {
		item.Folder = folder
		item.Status = "waiting"
		item.Title = util.FilterFileName(item.Title)
		_task := task.Task{TaskInDB: item}

		util.SqliteLock.Lock()
		result, err := stmt.Exec(
			item.Bvid, item.Cid, item.Format, item.Title, item.Owner,
			item.Cover, item.Status, item.Folder, item.Duration, item.DownloadType,
		)
		util.SqliteLock.Unlock()

		if err != nil {
			tx.Rollback()
			util.Res{Success: false, Message: fmt.Sprintf("插入任务失败: %v", err)}.Write(w)
			return
		}

		_task.ID, _ = result.LastInsertId()
		_task.CreateAt = time.Now()
		tasks = append(tasks, &_task)
	}

	util.SqliteLock.Lock()
	err = tx.Commit()
	util.SqliteLock.Unlock()

	if err != nil {
		util.Res{Success: false, Message: fmt.Sprintf("提交事务失败: %v", err)}.Write(w)
		return
	}

	// 批量启动下载任务
	for _, _task := range tasks {
		go _task.Start()
	}

	util.Res{Success: true, Message: fmt.Sprintf("成功创建 %d 个任务", len(tasks))}.Write(w)
}

func getActiveTask(w http.ResponseWriter, r *http.Request) {
	util.Res{Success: true, Data: task.GlobalTaskList}.Write(w)
}

func getTaskList(w http.ResponseWriter, r *http.Request) {
	err := r.ParseForm()
	if err != nil {
		util.Res{Success: false, Message: "参数错误"}.Write(w)
		return
	}
	db := util.MustGetDB()
	defer db.Close()
	page, err := strconv.Atoi(r.FormValue("page"))
	if err != nil {
		page = 0
	}
	pageSize, err := strconv.Atoi(r.FormValue("pageSize"))
	if err != nil {
		pageSize = 360
	}
	tasks, err := task.GetTaskList(db, page, pageSize)
	if err != nil {
		util.Res{Success: false, Message: err.Error()}.Write(w)
		return
	}
	util.Res{Success: true, Message: "获取成功", Data: tasks}.Write(w)
}

func deleteTask(w http.ResponseWriter, r *http.Request) {
	// 支持单个删除（GET 参数 id）和批量删除（POST 参数 ids）
	var taskIDs []int

	if r.Method == http.MethodPost {
		defer r.Body.Close()
		var body struct {
			IDs []int `json:"ids"`
		}
		if err := json.NewDecoder(r.Body).Decode(&body); err != nil {
			util.Res{Success: false, Message: "参数错误"}.Write(w)
			return
		}
		taskIDs = body.IDs
	} else {
		taskIDStr := r.FormValue("id")
		taskID, err := strconv.Atoi(taskIDStr)
		if err != nil {
			util.Res{Success: false, Message: "参数错误"}.Write(w)
			return
		}
		taskIDs = []int{taskID}
	}

	if len(taskIDs) == 0 {
		util.Res{Success: false, Message: "参数错误"}.Write(w)
		return
	}

	db := util.MustGetDB()
	defer db.Close()

	// 批量删除结果
	successCount := 0
	failedTasks := []struct {
		ID    int
		Error string
	}{}

	for _, taskID := range taskIDs {
		// 只删除数据库记录，不删除已下载的视频文件
		err := task.DeleteTask(db, taskID)
		if err != nil {
			failedTasks = append(failedTasks, struct {
				ID    int
				Error string
			}{ID: taskID, Error: fmt.Sprintf("数据库删除失败: %v", err)})
			continue
		}
		successCount++
	}

	if len(failedTasks) == 0 {
		util.Res{Success: true, Message: fmt.Sprintf("成功删除 %d 个任务", successCount)}.Write(w)
	} else {
		util.Res{
			Success: successCount > 0,
			Message: fmt.Sprintf("成功删除 %d 个任务，失败 %d 个", successCount, len(failedTasks)),
			Data:    failedTasks,
		}.Write(w)
	}
}

func cancelTask(w http.ResponseWriter, r *http.Request) {
	// 支持单个取消（GET 参数 id）和批量取消（POST 参数 ids）
	var taskIDs []int64

	if r.Method == http.MethodPost {
		defer r.Body.Close()
		var body struct {
			IDs []int64 `json:"ids"`
		}
		if err := json.NewDecoder(r.Body).Decode(&body); err != nil {
			util.Res{Success: false, Message: "参数错误"}.Write(w)
			return
		}
		taskIDs = body.IDs
	} else {
		taskIDStr := r.FormValue("id")
		taskID, err := strconv.ParseInt(taskIDStr, 10, 64)
		if err != nil {
			util.Res{Success: false, Message: "参数错误"}.Write(w)
			return
		}
		taskIDs = []int64{taskID}
	}

	if len(taskIDs) == 0 {
		util.Res{Success: false, Message: "参数错误"}.Write(w)
		return
	}

	// 批量取消结果
	successCount := 0
	failedIDs := []int64{}

	for _, taskID := range taskIDs {
		if task.CancelTask(taskID) {
			successCount++
		} else {
			failedIDs = append(failedIDs, taskID)
		}
	}

	if len(failedIDs) == 0 {
		util.Res{Success: true, Message: fmt.Sprintf("成功取消 %d 个任务", successCount)}.Write(w)
	} else {
		util.Res{
			Success: successCount > 0,
			Message: fmt.Sprintf("成功取消 %d 个任务，失败 %d 个", successCount, len(failedIDs)),
			Data:    failedIDs,
		}.Write(w)
	}
}