package web

import (
	"context"
	"errors"
	"net/http"

	"gitea.kazu634.com/kazu634/tver/internal/store"
)

type subscriptionActionView struct {
	ID, Genre, ErrorText                   string
	Subscribed, Choosing, DownloadExisting bool
}

type subscriptionView struct {
	ID, Title, CreatedAtText, LastCheckedText string
	CheckErrorAtText, CheckErrorText          string
	Enabled                                   bool
	Jobs                                      int64
}

type subscriptionsView struct {
	Items []subscriptionView
}

func (s *server) subscriptionChoice(w http.ResponseWriter, r *http.Request) {
	genre, id, ok := episodeForm(w, r)
	if !ok {
		return
	}
	ep, found := s.cachedEpisode(genre, id)
	if !found || ep.SeriesID == "" {
		http.Error(w, "新着キャッシュに番組がありません。新着を再表示してください", http.StatusNotFound)
		return
	}
	registered, err := s.isSubscribed(r.Context(), ep.SeriesID)
	if err != nil {
		s.logger.Printf("番組の登録状態取得に失敗: %v", err)
		http.Error(w, "登録状態を取得できませんでした", http.StatusInternalServerError)
		return
	}
	if registered {
		s.subscriptionRegisteredResponse(w, r, id, genre)
		return
	}
	s.render(w, "subscription_action", subscriptionActionView{ID: id, Genre: genre, Choosing: true})
}

func (s *server) registerSubscription(w http.ResponseWriter, r *http.Request) {
	genre, id, ok := episodeForm(w, r)
	if !ok {
		return
	}
	choice := r.Form.Get("download_existing")
	if choice != "" && choice != "1" {
		http.Error(w, "公開中の回の選択が不正です", http.StatusBadRequest)
		return
	}
	ep, found := s.cachedEpisode(genre, id)
	if !found || ep.SeriesID == "" || ep.SeriesTitle == "" {
		http.Error(w, "新着キャッシュに番組がありません。新着を再表示してください", http.StatusNotFound)
		return
	}
	registered, err := s.isSubscribed(r.Context(), ep.SeriesID)
	if err != nil {
		s.logger.Printf("番組の登録状態取得に失敗: %v", err)
		http.Error(w, "登録状態を取得できませんでした", http.StatusInternalServerError)
		return
	}
	if registered {
		s.subscriptionRegisteredResponse(w, r, id, genre)
		return
	}
	episodes, err := s.fetcher.FetchSeriesEpisodes(r.Context(), ep.SeriesID)
	if err != nil {
		s.logger.Printf("番組の公開中エピソード取得に失敗: %s", platformTokenPattern.ReplaceAllString(err.Error(), "${1}[REDACTED]"))
		s.render(w, "subscription_action", subscriptionActionView{ID: id, Genre: genre, Choosing: true, DownloadExisting: choice == "1", ErrorText: "公開中の回を取得できませんでした。再試行してください"})
		return
	}
	items := make([]store.Episode, 0, len(episodes))
	for _, episode := range episodes {
		items = append(items, storeEpisode(episode))
	}
	_, err = s.jobs.RegisterSubscription(r.Context(), ep.SeriesID, ep.SeriesTitle, items, choice == "1")
	if err != nil {
		s.logger.Printf("番組登録に失敗: %v", err)
		s.render(w, "subscription_action", subscriptionActionView{ID: id, Genre: genre, Choosing: true, DownloadExisting: choice == "1", ErrorText: "番組を登録できませんでした。再試行してください"})
		return
	}
	s.subscriptionRegisteredResponse(w, r, id, genre)
}

func (s *server) subscriptionRegisteredResponse(w http.ResponseWriter, r *http.Request, id, genre string) {
	if r.Header.Get("HX-Request") != "true" && r.Method == http.MethodPost {
		http.Redirect(w, r, "/?genre="+genre, http.StatusSeeOther)
		return
	}
	s.render(w, "subscription_action", subscriptionActionView{ID: id, Genre: genre, Subscribed: true})
}

func (s *server) isSubscribed(ctx context.Context, seriesID string) (bool, error) {
	result, err := s.jobs.SubscribedSeries(ctx, []string{seriesID})
	return result[seriesID], err
}

func (s *server) subscriptionsPage(w http.ResponseWriter, r *http.Request) {
	view, err := s.loadSubscriptions(r.Context())
	if err != nil {
		s.logger.Printf("登録番組の取得に失敗: %v", err)
		http.Error(w, "登録番組を取得できませんでした", http.StatusInternalServerError)
		return
	}
	s.render(w, "layout", page{Title: "登録番組", Subscriptions: &view})
}

func (s *server) subscriptionsFragment(w http.ResponseWriter, r *http.Request) {
	view, err := s.loadSubscriptions(r.Context())
	if err != nil {
		s.logger.Printf("登録番組の取得に失敗: %v", err)
		http.Error(w, "登録番組を取得できませんでした", http.StatusInternalServerError)
		return
	}
	s.render(w, "subscriptions_list", view)
}

func (s *server) loadSubscriptions(ctx context.Context) (subscriptionsView, error) {
	subs, err := s.jobs.ListSubscriptions(ctx)
	if err != nil {
		return subscriptionsView{}, err
	}
	view := subscriptionsView{Items: make([]subscriptionView, 0, len(subs))}
	for _, sub := range subs {
		item := subscriptionView{ID: sub.SeriesID, Title: sub.SeriesTitle,
			CreatedAtText:   sub.CreatedAt.In(s.zone).Format("2006-01-02 15:04 MST"),
			LastCheckedText: "未確認", Enabled: sub.Enabled, Jobs: sub.JobCount}
		if sub.LastCheckedAt != nil {
			item.LastCheckedText = sub.LastCheckedAt.In(s.zone).Format("2006-01-02 15:04 MST")
		}
		if sub.LastCheckErrorAt != nil && sub.LastCheckError != nil {
			item.CheckErrorAtText = sub.LastCheckErrorAt.In(s.zone).Format("2006-01-02 15:04 MST")
			item.CheckErrorText = *sub.LastCheckError
		}
		view.Items = append(view.Items, item)
	}
	return view, nil
}

func (s *server) pauseSubscription(w http.ResponseWriter, r *http.Request) {
	s.subscriptionMutation(w, r, func(ctx context.Context, id string) error {
		return s.jobs.SetSubscriptionEnabled(ctx, id, false)
	})
}

func (s *server) resumeSubscription(w http.ResponseWriter, r *http.Request) {
	s.subscriptionMutation(w, r, func(ctx context.Context, id string) error {
		return s.jobs.SetSubscriptionEnabled(ctx, id, true)
	})
}

func (s *server) deleteSubscription(w http.ResponseWriter, r *http.Request) {
	s.subscriptionMutation(w, r, func(ctx context.Context, id string) error {
		deleted, err := s.jobs.DeleteSubscription(ctx, id)
		if err == nil && !deleted {
			return store.ErrInvalidTransition
		}
		return err
	})
}

func (s *server) subscriptionMutation(w http.ResponseWriter, r *http.Request, change func(context.Context, string) error) {
	id := r.PathValue("id")
	if id == "" {
		http.Error(w, "番組 ID が不正です", http.StatusBadRequest)
		return
	}
	if err := change(r.Context(), id); err != nil {
		if errors.Is(err, store.ErrInvalidTransition) {
			http.Error(w, "番組が見つかりません", http.StatusNotFound)
		} else {
			s.logger.Printf("登録番組の操作に失敗: %v", err)
			http.Error(w, "登録番組を変更できませんでした", http.StatusInternalServerError)
		}
		return
	}
	if r.Header.Get("HX-Request") != "true" {
		http.Redirect(w, r, "/subscriptions", http.StatusSeeOther)
		return
	}
	s.subscriptionsFragment(w, r)
}