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"
)

type SyncEmptyClassroomsRequest struct {
	Username    string `json:"username" binding:"required"`
	Password    string `json:"password" binding:"required"`
	Semester    string `json:"semester"`
	WeekStart   string `json:"week_start"`
	WeekEnd     string `json:"week_end"`
	CampusCode  string `json:"campus_code"`
}

type SyncEmptyClassroomsResult struct {
	Success      bool   `json:"success"`
	Message      string `json:"message"`
	SyncedCount  int    `json:"synced_count"`
	ErrorMessage string `json:"error_message,omitempty"`
}

type EmptyClassroomSyncService interface {
	SyncUserEmptyClassrooms(ctx context.Context, userID string, req *SyncEmptyClassroomsRequest) (*SyncEmptyClassroomsResult, error)
}

type emptyClassroomSyncService struct {
	taskManager *runner.TaskManager
	classroomRepo repository.EmptyClassroomRepository
	logger        *zap.Logger
}

func NewEmptyClassroomSyncService(
	taskManager *runner.TaskManager,
	classroomRepo repository.EmptyClassroomRepository,
	logger *zap.Logger,
) EmptyClassroomSyncService {
	return &emptyClassroomSyncService{
		taskManager:    taskManager,
		classroomRepo:  classroomRepo,
		logger:         logger,
	}
}

func (s *emptyClassroomSyncService) SyncUserEmptyClassrooms(ctx context.Context, userID string, req *SyncEmptyClassroomsRequest) (*SyncEmptyClassroomsResult, error) {
	payload := &pb.GetEmptyClassroomPayload{
		Username:    req.Username,
		Password:    req.Password,
		Semester:    req.Semester,
		WeekStart:   req.WeekStart,
		WeekEnd:     req.WeekEnd,
		CampusCode:  req.CampusCode,
	}

	taskResult, err := s.taskManager.SubmitTaskSync(ctx, pb.TaskType_TASK_TYPE_GET_EMPTY_CLASSROOM, payload)
	if err != nil {
		s.logger.Error("failed to submit empty classroom 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 &SyncEmptyClassroomsResult{
			Success:      false,
			Message:      "空教室查询失败",
			ErrorMessage: taskResult.ErrorMessage,
		}, nil
	}

	var resultData pb.EmptyClassroomResultData
	if err := json.Unmarshal(taskResult.Data, &resultData); err != nil {
		s.logger.Error("failed to parse empty classroom result",
			zap.String("user_id", userID),
			zap.Error(err))
		return nil, fmt.Errorf("failed to parse result: %w", err)
	}

	classrooms := s.convertClassrooms(userID, &resultData)
	if err := s.saveClassrooms(ctx, userID, resultData.Semester, classrooms); err != nil {
		s.logger.Error("failed to save empty classrooms",
			zap.String("user_id", userID),
			zap.Error(err))
		return nil, fmt.Errorf("failed to save classrooms: %w", err)
	}

	s.logger.Info("empty classrooms sync completed",
		zap.String("user_id", userID),
		zap.Int("classroom_count", len(classrooms)))

	return &SyncEmptyClassroomsResult{
		Success:     true,
		Message:     "空教室查询成功",
		SyncedCount: len(classrooms),
	}, nil
}

func (s *emptyClassroomSyncService) convertClassrooms(userID string, data *pb.EmptyClassroomResultData) []*model.EmptyClassroom {
	classrooms := make([]*model.EmptyClassroom, 0, len(data.Classrooms))
	for _, c := range data.Classrooms {
		classrooms = append(classrooms, &model.EmptyClassroom{
			ID:        uuid.New().String(),
			UserID:    userID,
			Semester:  data.Semester,
			Classroom: c.Classroom,
			Weekday:   c.Weekday,
			Periods:   c.Periods,
			Weeks:     c.Weeks,
		})
	}
	return classrooms
}

func (s *emptyClassroomSyncService) saveClassrooms(ctx context.Context, userID, semester string, classrooms []*model.EmptyClassroom) error {
	if err := s.classroomRepo.DeleteByUserAndSemester(ctx, userID, semester); err != nil {
		return fmt.Errorf("failed to delete old classrooms: %w", err)
	}
	if len(classrooms) == 0 {
		return nil
	}
	if err := s.classroomRepo.BatchCreate(ctx, classrooms); err != nil {
		return fmt.Errorf("failed to create classrooms: %w", err)
	}
	return nil
}