package service

import (
	"context"
	"log/slog"

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

	pb "schedule_converter/proto/runner"
)

// GetGrades 获取成绩：登录 → 优先 GPA 页面 → 回退到成绩页面 → 解析 → 转换为 pb 结果。
func (s *Service) GetGrades(ctx context.Context, req *pb.GetGradesPayload) (*pb.GradesResultData, 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 gpaSummary *pb.GpaSummary

	gpaHTML, err := client.FetchHTML(ctx, httpClient, "GET", "/xfj/queryListXfj", nil, "", "")
	if err != nil {
		log.Warn("获取GPA页面失败，尝试成绩页面", "error", err)
		gradesHTML, ferr := client.FetchHTML(ctx, httpClient, "GET", "/cjcx/queryQmcj", nil, "", "")
		if ferr != nil {
			return nil, apperr.New("fetch_grades", ferr, "获取成绩失败")
		}
		grades, perr := parser.ParseGradesHTML(gradesHTML)
		if perr != nil {
			return nil, apperr.New("parse_grades", perr, "解析成绩失败")
		}
		return &pb.GradesResultData{
			StudentId: req.Username,
			Semester:  req.Semester,
			Grades:    convertGrades(grades),
		}, nil
	}

	summary, grades, err := parser.ParseGPAHTML(gpaHTML)
	if err != nil {
		return nil, apperr.New("parse_gpa", err, "解析学分绩失败")
	}
	if summary != nil {
		gpaSummary = &pb.GpaSummary{
			AverageGpa:       summary.AverageGPA,
			Rank:             summary.Rank,
			ExamTotalGpa:     summary.ExamTotalGPA,
			ExamTotalCredits: summary.ExamTotalCredits,
			FailCredits:      summary.FailCredits,
			Semesters:        summary.Semesters,
		}
	}

	return &pb.GradesResultData{
		StudentId:  req.Username,
		Semester:   req.Semester,
		Grades:     convertGrades(grades),
		GpaSummary: gpaSummary,
	}, nil
}

// convertGrades 将内部成绩模型转换为 pb.Grade 列表。
func convertGrades(grades []models.GradeEntry) []*pb.Grade {
	result := make([]*pb.Grade, 0, len(grades))
	for _, g := range grades {
		result = append(result, &pb.Grade{
			Term:       g.Term,
			CourseCode: g.Code,
			CourseName: g.Name,
			Nature:     g.Nature,
			Category:   g.Category,
			Credit:     g.Credit,
			Score:      g.Score,
			GradePoint: g.GradePoint,
			IsExam:     g.IsExam,
		})
	}
	return result
}