package api

import (
	"encoding/json"
	"net/http"
	"strings"

	"github.com/krau/SaveAny-Bot/core"
	"github.com/krau/SaveAny-Bot/pkg/enums/tasktype"
	"github.com/krau/SaveAny-Bot/storage"
)

// Handlers 处理器结构体
type Handlers struct {
	factory *TaskFactory
}

// NewHandlers 创建处理器
func NewHandlers(factory *TaskFactory) *Handlers {
	return &Handlers{factory: factory}
}

// CreateTaskHandler 创建任务处理器
func (h *Handlers) CreateTaskHandler(w http.ResponseWriter, r *http.Request) {
	if r.Method != http.MethodPost {
		WriteError(w, http.StatusMethodNotAllowed, "method_not_allowed", "only POST method is allowed")
		return
	}

	var req CreateTaskRequest
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		WriteError(w, http.StatusBadRequest, "invalid_request", "failed to decode request body: "+err.Error())
		return
	}

	// 验证请求
	if req.Type == "" {
		WriteError(w, http.StatusBadRequest, "invalid_request", "task type is required")
		return
	}

	if req.Storage == "" {
		WriteError(w, http.StatusBadRequest, "invalid_request", "storage is required")
		return
	}

	// 创建任务
	resp, err := h.factory.CreateTask(&req)
	if err != nil {
		WriteError(w, http.StatusBadRequest, "task_creation_failed", err.Error())
		return
	}

	WriteJSON(w, http.StatusCreated, resp)
}

// ListTasksHandler 列出任务处理器
func (h *Handlers) ListTasksHandler(w http.ResponseWriter, r *http.Request) {
	if r.Method != http.MethodGet {
		WriteError(w, http.StatusMethodNotAllowed, "method_not_allowed", "only GET method is allowed")
		return
	}

	tasks := GetAllTasks()
	response := make([]TaskInfoResponse, 0, len(tasks))

	for _, task := range tasks {
		info := convertTaskProgressToResponse(task)
		response = append(response, info)
	}

	WriteJSON(w, http.StatusOK, TasksListResponse{
		Tasks: response,
		Total: len(response),
	})
}

// GetTaskHandler 获取单个任务处理器
func (h *Handlers) GetTaskHandler(w http.ResponseWriter, r *http.Request) {
	if r.Method != http.MethodGet {
		WriteError(w, http.StatusMethodNotAllowed, "method_not_allowed", "only GET method is allowed")
		return
	}

	taskID := extractTaskIDFromPath(r.URL.Path)
	if taskID == "" {
		WriteError(w, http.StatusBadRequest, "invalid_request", "task ID is required")
		return
	}

	task, ok := GetTask(taskID)
	if !ok {
		WriteError(w, http.StatusNotFound, "task_not_found", "task not found: "+taskID)
		return
	}

	resp := convertTaskProgressToResponse(task)
	WriteJSON(w, http.StatusOK, resp)
}

// CancelTaskHandler 取消任务处理器
func (h *Handlers) CancelTaskHandler(w http.ResponseWriter, r *http.Request) {
	if r.Method != http.MethodDelete {
		WriteError(w, http.StatusMethodNotAllowed, "method_not_allowed", "only DELETE method is allowed")
		return
	}

	taskID := extractTaskIDFromPath(r.URL.Path)
	if taskID == "" {
		WriteError(w, http.StatusBadRequest, "invalid_request", "task ID is required")
		return
	}

	task, ok := GetTask(taskID)
	if !ok {
		WriteError(w, http.StatusNotFound, "task_not_found", "task not found: "+taskID)
		return
	}

	// 取消任务
	if err := core.CancelTask(r.Context(), taskID); err != nil {
		WriteError(w, http.StatusInternalServerError, "cancel_failed", "failed to cancel task: "+err.Error())
		return
	}

	task.UpdateStatus(TaskStatusCancelled)
	WriteJSON(w, http.StatusOK, map[string]string{"message": "task cancelled successfully"})
}

// ListStoragesHandler 列出存储处理器
func (h *Handlers) ListStoragesHandler(w http.ResponseWriter, r *http.Request) {
	if r.Method != http.MethodGet {
		WriteError(w, http.StatusMethodNotAllowed, "method_not_allowed", "only GET method is allowed")
		return
	}

	storages := make([]StorageInfo, 0, len(storage.Storages))
	for name, stor := range storage.Storages {
		storages = append(storages, StorageInfo{
			Name: name,
			Type: string(stor.Type()),
		})
	}

	WriteJSON(w, http.StatusOK, StoragesResponse{Storages: storages})
}

// GetTaskTypesHandler 获取支持的任务类型
func (h *Handlers) GetTaskTypesHandler(w http.ResponseWriter, r *http.Request) {
	if r.Method != http.MethodGet {
		WriteError(w, http.StatusMethodNotAllowed, "method_not_allowed", "only GET method is allowed")
		return
	}

	types := []tasktype.TaskType{
		tasktype.TaskTypeDirectlinks,
		tasktype.TaskTypeYtdlp,
		tasktype.TaskTypeAria2,
		tasktype.TaskTypeParseditem,
		tasktype.TaskTypeTgfiles,
		tasktype.TaskTypeTphpics,
		tasktype.TaskTypeTransfer,
	}

	WriteJSON(w, http.StatusOK, map[string]any{
		"types": types,
	})
}

// HealthCheckHandler 健康检查处理器
func (h *Handlers) HealthCheckHandler(w http.ResponseWriter, r *http.Request) {
	WriteJSON(w, http.StatusOK, map[string]string{
		"status": "ok",
	})
}

// extractTaskIDFromPath 从路径中提取任务 ID
// 路径格式: /api/v1/tasks/:id
func extractTaskIDFromPath(path string) string {
	parts := strings.Split(strings.Trim(path, "/"), "/")
	if len(parts) < 4 {
		return ""
	}
	return parts[3]
}

// convertTaskProgressToResponse 将任务进度转换为响应格式
func convertTaskProgressToResponse(task *TaskProgressInfo) TaskInfoResponse {
	resp := TaskInfoResponse{
		TaskID:    task.TaskID,
		Type:      tasktype.TaskType(task.Type),
		Status:    task.Status,
		Title:     task.Title,
		Storage:   task.Storage,
		Path:      task.Path,
		Error:     task.Error,
		CreatedAt: task.CreatedAt,
		UpdatedAt: task.UpdatedAt,
	}

	// 计算进度
	if task.TotalBytes > 0 {
		percent := float64(task.DownloadedBytes) * 100 / float64(task.TotalBytes)
		resp.Progress = &TaskProgress{
			TotalBytes:      task.TotalBytes,
			DownloadedBytes: task.DownloadedBytes,
			Percent:         percent,
		}
	}

	return resp
}

// NotFoundHandler 404 处理器
func NotFoundHandler(w http.ResponseWriter, r *http.Request) {
	WriteError(w, http.StatusNotFound, "not_found", "endpoint not found: "+r.URL.Path)
}

// MethodNotAllowedHandler 405 处理器
func MethodNotAllowedHandler(w http.ResponseWriter, r *http.Request) {
	WriteError(w, http.StatusMethodNotAllowed, "method_not_allowed", "method not allowed: "+r.Method)
}