package service

import (
	"context"
	"fmt"
	"strings"

	"schedule_converter/client"
	"schedule_converter/config"
	"schedule_converter/models"
	"schedule_converter/parser"
	apperr "schedule_converter/pkg/errors"

	pb "schedule_converter/proto/runner"
)

// GetSchedule 获取课表：登录 → POST 查询 → 解析 → 转换为 pb 结果。
func (s *Service) GetSchedule(ctx context.Context, req *pb.GetSchedulePayload) (*pb.ScheduleResultData, error) {
	httpClient, err := s.newAuthenticatedClient(ctx, req.Username, req.Password, "")
	if err != nil {
		return nil, err
	}

	semester := req.Semester
	if semester == "" {
		semester = config.Get().Semester
	}

	data := fmt.Sprintf("xnxq=%s", semester)
	html, err := client.FetchHTML(ctx, httpClient, "POST", "/kbcx/queryGrkb", strings.NewReader(data), "application/x-www-form-urlencoded", "")
	if err != nil {
		return nil, apperr.New("fetch_schedule", err, "获取课表失败")
	}

	courses, err := parser.ParseScheduleHTML(html)
	if err != nil {
		return nil, apperr.New("parse_schedule", err, "解析课表失败")
	}

	return &pb.ScheduleResultData{
		StudentId: req.Username,
		Semester:  semester,
		Courses:   convertCourses(courses),
	}, nil
}

// convertCourses 将内部课程模型转换为 pb.Course 列表。
func convertCourses(courses []models.Course) []*pb.Course {
	result := make([]*pb.Course, len(courses))
	for i, c := range courses {
		schedule := make([]*pb.ScheduleTime, len(c.Schedule))
		for j, sc := range c.Schedule {
			schedule[j] = &pb.ScheduleTime{
				Day:      sc.Day,
				Sections: toInt32Slice(sc.Section),
				Weeks:    toInt32Slice(sc.Weeks),
			}
		}
		result[i] = &pb.Course{
			Name:     c.Name,
			Teacher:  c.Teacher,
			Room:     c.Room,
			Schedule: schedule,
		}
	}
	return result
}

func toInt32Slice(arr []int) []int32 {
	result := make([]int32, len(arr))
	for i, v := range arr {
		result[i] = int32(v)
	}
	return result
}