package handler

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

	"github.com/gin-gonic/gin"
	"github.com/gorilla/websocket"

	"spider/internal/model"
	"spider/internal/store"
	"spider/internal/task"
)

// TaskHandler handles task-related HTTP and WebSocket requests.
type TaskHandler struct {
	store   *store.Store
	taskMgr *task.Manager
}

// List handles GET /tasks
func (h *TaskHandler) List(c *gin.Context) {
	page, pageSize, offset := parsePage(c)
	status := c.Query("status")

	query := h.store.DB.Model(&model.TaskLog{}).Order("created_at DESC")
	if status != "" {
		query = query.Where("status = ?", status)
	}

	var total int64
	query.Count(&total)

	var tasks []model.TaskLog
	if err := query.Limit(pageSize).Offset(offset).Find(&tasks).Error; err != nil {
		Fail(c, 500, err.Error())
		return
	}

	PageOK(c, tasks, total, page, pageSize)
}

// Start handles POST /tasks/start
func (h *TaskHandler) Start(c *gin.Context) {
	var req task.StartRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		Fail(c, 400, err.Error())
		return
	}

	// Special case: clean task
	if req.PluginName == "clean" {
		taskLog, err := h.taskMgr.StartClean()
		if err != nil {
			Fail(c, 409, err.Error())
			return
		}
		c.JSON(http.StatusCreated, Response{Code: 0, Message: "ok", Data: taskLog})
		return
	}

	taskLog, err := h.taskMgr.StartTask(req)
	if err != nil {
		Fail(c, 409, err.Error())
		return
	}

	c.JSON(http.StatusCreated, Response{Code: 0, Message: "ok", Data: taskLog})
}

// Get handles GET /tasks/:id
func (h *TaskHandler) Get(c *gin.Context) {
	id, err := strconv.ParseUint(c.Param("id"), 10, 64)
	if err != nil {
		Fail(c, 400, "invalid id")
		return
	}

	var taskLog model.TaskLog
	if err := h.store.DB.First(&taskLog, id).Error; err != nil {
		Fail(c, 404, "task not found")
		return
	}

	progress := h.taskMgr.GetProgress(uint(id))

	OK(c, gin.H{
		"task":     taskLog,
		"progress": progress,
	})
}

// Stop handles POST /tasks/:id/stop
func (h *TaskHandler) Stop(c *gin.Context) {
	id, err := strconv.ParseUint(c.Param("id"), 10, 64)
	if err != nil {
		Fail(c, 400, "invalid id")
		return
	}

	if err := h.taskMgr.StopTask(uint(id)); err != nil {
		Fail(c, 500, err.Error())
		return
	}

	OK(c, gin.H{"message": "stop signal sent"})
}

// Logs handles GET /tasks/:id/logs via WebSocket.
func (h *TaskHandler) Logs(c *gin.Context) {
	id, err := strconv.ParseUint(c.Param("id"), 10, 64)
	if err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": "invalid id"})
		return
	}

	upgrader := websocket.Upgrader{
		CheckOrigin: func(r *http.Request) bool { return true },
	}

	conn, err := upgrader.Upgrade(c.Writer, c.Request, nil)
	if err != nil {
		return
	}
	defer conn.Close()

	send := func(msg string) bool {
		err := conn.WriteMessage(websocket.TextMessage, []byte(msg))
		return err == nil
	}

	// Fetch task record
	var taskLog model.TaskLog
	if err := h.store.DB.First(&taskLog, id).Error; err != nil {
		send(fmt.Sprintf("[错误] 任务 #%d 不存在", id))
		return
	}

	// Send history logs
	logs := h.taskMgr.GetLogs(uint(id))
	for _, line := range logs {
		if !send(line) {
			return
		}
	}

	// If finished, close
	if taskLog.Status == "completed" || taskLog.Status == "failed" || taskLog.Status == "stopped" {
		send(fmt.Sprintf("[完成] 任务已结束，状态: %s", taskLog.Status))
		return
	}

	// Stream live updates
	clientGone := make(chan struct{})
	go func() {
		for {
			if _, _, err := conn.ReadMessage(); err != nil {
				close(clientGone)
				return
			}
		}
	}()

	ticker := time.NewTicker(time.Second)
	defer ticker.Stop()

	for {
		select {
		case <-clientGone:
			return
		case <-ticker.C:
			var t model.TaskLog
			if err := h.store.DB.First(&t, id).Error; err != nil {
				return
			}

			progress := h.taskMgr.GetProgress(uint(id))
			if progress != nil {
				msg := fmt.Sprintf("[进度] %v", progress["message"])
				if !send(msg) {
					return
				}
			}

			if t.Status == "completed" || t.Status == "failed" || t.Status == "stopped" {
				send(fmt.Sprintf("[完成] 任务已结束，状态: %s", t.Status))
				return
			}
		}
	}
}