package service

import (
	"context"
	"encoding/json"
	"fmt"

	"with_you/internal/grpc/runner"
	"with_you/internal/model"
	"with_you/internal/repository"
	pb "with_you/proto/runner"

	"github.com/google/uuid"
	"go.uber.org/zap"
)

// SyncScheduleRequest 同步课表请求
type SyncScheduleRequest struct {
	Username string `json:"username" binding:"required"`
	Password string `json:"password" binding:"required"`
	Semester string `json:"semester"` // 可选，默认当前学期
}

// SyncScheduleResult 同步课表结果
type SyncScheduleResult struct {
	Success      bool   `json:"success"`
	Message      string `json:"message"`
	SyncedCount  int    `json:"synced_count"`
	ErrorMessage string `json:"error_message,omitempty"`
}

// ScheduleSyncService 课表同步服务接口
type ScheduleSyncService interface {
	SyncUserSchedule(ctx context.Context, userID string, req *SyncScheduleRequest) (*SyncScheduleResult, error)
}

type scheduleSyncService struct {
	taskManager  *runner.TaskManager
	scheduleRepo repository.ScheduleRepository
	logger       *zap.Logger
}

// NewScheduleSyncService 创建课表同步服务
func NewScheduleSyncService(
	taskManager *runner.TaskManager,
	scheduleRepo repository.ScheduleRepository,
	logger *zap.Logger,
) ScheduleSyncService {
	return &scheduleSyncService{
		taskManager:  taskManager,
		scheduleRepo: scheduleRepo,
		logger:       logger,
	}
}

// SyncUserSchedule 同步用户课表
func (s *scheduleSyncService) SyncUserSchedule(ctx context.Context, userID string, req *SyncScheduleRequest) (*SyncScheduleResult, error) {
	// 构建任务载荷
	payload := &pb.GetSchedulePayload{
		Username: req.Username,
		Password: req.Password,
		Semester: req.Semester,
	}

	// 同步提交任务并等待结果
	taskResult, err := s.taskManager.SubmitTaskSync(ctx, pb.TaskType_TASK_TYPE_GET_SCHEDULE, payload)
	if err != nil {
		s.logger.Error("failed to submit sync task",
			zap.String("user_id", userID),
			zap.Error(err))
		return nil, fmt.Errorf("failed to submit task: %w", err)
	}

	if taskResult.Status != pb.TaskStatus_TASK_STATUS_SUCCESS {
		return &SyncScheduleResult{
			Success:      false,
			Message:      "课表获取失败",
			ErrorMessage: taskResult.ErrorMessage,
		}, nil
	}

	// 解析结果数据
	var resultData pb.ScheduleResultData
	if err := json.Unmarshal(taskResult.Data, &resultData); err != nil {
		s.logger.Error("failed to parse schedule result",
			zap.String("user_id", userID),
			zap.Error(err))
		return nil, fmt.Errorf("failed to parse result: %w", err)
	}

	// 转换并保存课表
	courses := s.convertCourses(&resultData)
	if err := s.saveCourses(ctx, userID, courses); err != nil {
		s.logger.Error("failed to save courses",
			zap.String("user_id", userID),
			zap.Error(err))
		return nil, fmt.Errorf("failed to save courses: %w", err)
	}

	s.logger.Info("schedule sync completed",
		zap.String("user_id", userID),
		zap.Int("course_count", len(courses)))

	return &SyncScheduleResult{
		Success:     true,
		Message:     "课表同步成功",
		SyncedCount: len(courses),
	}, nil
}

// convertCourses 转换 converter 课表数据为 backend 模型
func (s *scheduleSyncService) convertCourses(data *pb.ScheduleResultData) []*model.ScheduleCourse {
	var courses []*model.ScheduleCourse

	for _, c := range data.Courses {
		for _, st := range c.Schedule {
			dayOfWeek := 0
			if _, err := fmt.Sscanf(st.Day, "%d", &dayOfWeek); err != nil {
				zap.L().Warn("invalid day format in schedule sync", zap.String("day", st.Day), zap.Error(err))
				dayOfWeek = 0
			}

			startSection := 1
			endSection := 1
			if len(st.Sections) > 0 {
				startSection = int(st.Sections[0])
				endSection = int(st.Sections[len(st.Sections)-1])
			}

			// 转换周次数组
			var weeks []int
			for _, w := range st.Weeks {
				weeks = append(weeks, int(w))
			}
			weeksJSON, _ := json.Marshal(weeks)

			course := &model.ScheduleCourse{
				ID:           uuid.New().String(),
				Name:         c.Name,
				Teacher:      c.Teacher,
				Location:     c.Room,
				DayOfWeek:    dayOfWeek,
				StartSection: startSection,
				EndSection:   endSection,
				Weeks:        string(weeksJSON),
				Color:        generateCourseColor(c.Name),
			}
			courses = append(courses, course)
		}
	}

	return courses
}

// saveCourses 保存课表到数据库
func (s *scheduleSyncService) saveCourses(ctx context.Context, userID string, courses []*model.ScheduleCourse) error {
	// 先删除用户旧课表
	if err := s.scheduleRepo.DeleteByUserID(ctx, userID); err != nil {
		return fmt.Errorf("failed to delete old courses: %w", err)
	}

	// 设置用户 ID 并保存
	for _, c := range courses {
		c.UserID = userID
		if err := s.scheduleRepo.Create(c); err != nil {
			return fmt.Errorf("failed to create course: %w", err)
		}
	}

	return nil
}

// generateCourseColor 根据课程名生成颜色
func generateCourseColor(name string) string {
	// 预定义的课程颜色列表
	colors := []string{
		"#3498DB", // 蓝色
		"#2ECC71", // 绿色
		"#E74C3C", // 红色
		"#F39C12", // 橙色
		"#9B59B6", // 紫色
		"#1ABC9C", // 青色
		"#E67E22", // 深橙色
		"#34495E", // 深灰色
		"#16A085", // 深青色
		"#27AE60", // 深绿色
	}

	// 根据课程名哈希选择颜色
	hash := 0
	for _, c := range name {
		hash = (hash + int(c)) % len(colors)
	}
	return colors[hash]
}