package service

import (
	"context"
	"crypto/sha256"
	"encoding/hex"
	"fmt"
	"path/filepath"
	"sort"
	"strconv"
	"strings"

	"github.com/ShukeBta/MediaStationGo/internal/model"
)

func (e *EmbyService) seriesIDForMedia(m *model.Media) string {
	if strings.TrimSpace(m.SeriesID) != "" {
		return m.SeriesID
	}
	return stableEmbyID(embyVirtualSeriesPrefix, m.LibraryID, e.seriesNameForMedia(m))
}

func (e *EmbyService) seasonIDForMedia(m *model.Media) string {
	return seasonID(e.seriesIDForMedia(m), m.SeasonNum)
}

func (e *EmbyService) seriesNameForMedia(m *model.Media) string {
	if strings.TrimSpace(m.SeriesID) != "" {
		if series, err := e.repo.Series.FindByID(context.Background(), m.SeriesID); err == nil && series != nil && strings.TrimSpace(series.Title) != "" {
			return series.Title
		}
	}
	if name := inferSeriesNameFromPath(m.Path); name != "" {
		return name
	}
	name := strings.TrimSpace(m.Title)
	name = embyEpisodeTitleRE.ReplaceAllString(name, "")
	name = embyYearSuffixRE.ReplaceAllString(name, "")
	if name == "" {
		name = strings.TrimSpace(m.OriginalName)
	}
	return name
}

func inferSeriesNameFromPath(path string) string {
	path = strings.TrimSpace(path)
	if path == "" {
		return ""
	}
	dir := filepath.Dir(path)
	base := filepath.Base(dir)
	if embySeasonDirRE.MatchString(base) {
		dir = filepath.Dir(dir)
		base = filepath.Base(dir)
	}
	base = strings.TrimSpace(embyYearSuffixRE.ReplaceAllString(base, ""))
	if base == "." || base == string(filepath.Separator) {
		return ""
	}
	return base
}

func stableEmbyID(prefix string, parts ...string) string {
	h := sha256.New()
	for _, part := range parts {
		_, _ = h.Write([]byte(strings.ToLower(strings.TrimSpace(part))))
		_, _ = h.Write([]byte{0})
	}
	return prefix + hex.EncodeToString(h.Sum(nil))[:32]
}

func seasonID(seriesID string, seasonNum int) string {
	if seasonNum < 0 {
		seasonNum = 1
	}
	return stableEmbyID(embyVirtualSeasonPrefix, seriesID, strconv.Itoa(seasonNum))
}

func seasonName(seasonNum int) string {
	if seasonNum == 0 {
		return "特别篇"
	}
	if seasonNum < 0 {
		seasonNum = 1
	}
	return fmt.Sprintf("第 %d 季", seasonNum)
}

func sortSeriesGroups(groups []embySeriesGroup, p ItemsParams) {
	switch strings.ToLower(p.SortBy) {
	case "sortname", "name":
		sort.SliceStable(groups, func(i, j int) bool {
			if strings.EqualFold(p.SortOrder, "Descending") {
				return groups[i].Name > groups[j].Name
			}
			return groups[i].Name < groups[j].Name
		})
	default:
		sort.SliceStable(groups, func(i, j int) bool {
			if strings.EqualFold(p.SortOrder, "Ascending") {
				return groups[i].CreatedAt.Before(groups[j].CreatedAt)
			}
			return groups[i].CreatedAt.After(groups[j].CreatedAt)
		})
	}
}