package parser

import (
	"fmt"
	"log/slog"
	"net/http"
	"strings"

	"schedule_converter/client"
	"schedule_converter/config"

	"github.com/PuerkitoBio/goquery"
)

type ExamType string

const (
	ExamTypeFinal   ExamType = "final"
	ExamTypeMidterm ExamType = "midterm"
	ExamTypeMakeup  ExamType = "makeup"
)

type ExamEntry struct {
	Course  string
	Date    string
	Time    string
	Week    string
	Weekday string
	Type    ExamType
}

func examTypeToCode(t ExamType) string {
	switch t {
	case ExamTypeMidterm:
		return "02"
	case ExamTypeMakeup:
		return "03"
	default:
		return "01"
	}
}

func FetchExams(httpClient *http.Client, examType ExamType) ([]ExamEntry, error) {
	examURL := config.Get().BaseURL + "/kscx/queryKsForXs"
	log := slog.With("exam_type", string(examType))
	log.Info("获取考试时间数据")

	data := fmt.Sprintf("xnxq=&kssjd=%s", examTypeToCode(examType))
	req, err := http.NewRequest("POST", examURL, strings.NewReader(data))
	if err != nil {
		return nil, err
	}

	req.Header = client.GetHeadersWithContentType("application/x-www-form-urlencoded")

	resp, err := httpClient.Do(req)
	if err != nil {
		return nil, err
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		return nil, fmt.Errorf("获取考试数据失败, 状态码: %d", resp.StatusCode)
	}

	html, err := decodeResponseBody(resp)
	if err != nil {
		return nil, err
	}

	exams, err := parseExamTimeHTML(html, examType)
	if err != nil {
		return nil, err
	}

	log.Info("考试数据获取完成", "exam_count", len(exams))
	return exams, nil
}

func FetchAllExams(httpClient *http.Client) ([]ExamEntry, error) {
	var allExams []ExamEntry
	var lastErr error
	for _, et := range []ExamType{ExamTypeFinal, ExamTypeMidterm, ExamTypeMakeup} {
		exams, err := FetchExams(httpClient, et)
		if err != nil {
			slog.Warn("获取考试数据失败", "exam_type", string(et), "error", err)
			lastErr = err
			continue
		}
		allExams = append(allExams, exams...)
	}
	if len(allExams) == 0 && lastErr != nil {
		return nil, fmt.Errorf("所有考试类型获取均失败: %w", lastErr)
	}
	return allExams, nil
}

func parseExamTimeHTML(html string, examType ExamType) ([]ExamEntry, error) {
	doc, err := goquery.NewDocumentFromReader(strings.NewReader(html))
	if err != nil {
		return nil, err
	}

	var exams []ExamEntry

	doc.Find("table.bot_line").Each(func(_ int, table *goquery.Selection) {
		rows := table.Find("tr")
		if rows.Length() < 2 {
			return
		}

		rows.Each(func(idx int, row *goquery.Selection) {
			if idx == 0 {
				return
			}
			cells := row.Find("td")
			if cells.Length() < 6 {
				return
			}

			texts := getCellTexts(cells)

			exam := ExamEntry{
				Course:  safeGet(texts, 1),
				Date:    safeGet(texts, 2),
				Time:    safeGet(texts, 3),
				Week:    safeGet(texts, 4),
				Weekday: safeGet(texts, 5),
				Type:    examType,
			}

			if exam.Course != "" && len(exam.Course) >= 2 {
				exams = append(exams, exam)
			}
		})
	})

	return exams, nil
}