package service

import (
	"context"
	"fmt"
	"log/slog"
	"strings"

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

	pb "schedule_converter/proto/runner"
)

var allExamTypes = []models.ExamType{models.ExamTypeFinal, models.ExamTypeMidterm, models.ExamTypeMakeup}

// GetExams 获取考试安排：登录 → 遍历各考试类型抓取并解析 → 合并 → 转换为 pb 结果。
func (s *Service) GetExams(ctx context.Context, req *pb.GetExamsPayload) (*pb.ExamsResultData, error) {
	log := slog.With("username", req.Username, "semester", req.Semester)

	httpClient, err := s.newAuthenticatedClient(ctx, req.Username, req.Password, "")
	if err != nil {
		return nil, err
	}

	var allExams []models.ExamEntry
	var lastErr error
	for _, et := range allExamTypes {
		data := fmt.Sprintf("xnxq=&kssjd=%s", parser.ExamTypeCode(et))
		html, ferr := client.FetchHTML(ctx, httpClient, "POST", "/kscx/queryKsForXs", strings.NewReader(data), "application/x-www-form-urlencoded", "")
		if ferr != nil {
			log.Warn("获取考试数据失败", "exam_type", string(et), "error", ferr)
			lastErr = ferr
			continue
		}
		exams, perr := parser.ParseExamHTML(html, et)
		if perr != nil {
			log.Warn("解析考试数据失败", "exam_type", string(et), "error", perr)
			lastErr = perr
			continue
		}
		allExams = append(allExams, exams...)
	}

	if len(allExams) == 0 && lastErr != nil {
		return nil, apperr.New("fetch_exams", lastErr, "所有考试类型获取均失败")
	}

	return &pb.ExamsResultData{
		StudentId: req.Username,
		Semester:  req.Semester,
		Exams:     convertExams(allExams),
	}, nil
}

// convertExams 将内部考试模型转换为 pb.Exam 列表。
func convertExams(exams []models.ExamEntry) []*pb.Exam {
	result := make([]*pb.Exam, 0, len(exams))
	for _, e := range exams {
		examTypeStr := "期末"
		switch e.Type {
		case models.ExamTypeMidterm:
			examTypeStr = "期中"
		case models.ExamTypeMakeup:
			examTypeStr = "补考"
		}
		result = append(result, &pb.Exam{
			CourseName: e.Course,
			ExamType:   examTypeStr,
			Date:       e.Date,
			Time:       e.Time,
			Week:       e.Week,
			Weekday:    e.Weekday,
		})
	}
	return result
}