package handler

import (
	"context"
	"fmt"
	"strconv"

	"uptodownBot/internal/domain"
)

func (h *Handler) handlePlaylist(ctx context.Context, chatID int64, userID int64, url string, info *domain.MediaInfo) {
	state := &domain.PlaylistState{
		Entries:  info.PlaylistEntries,
		Page:     0,
		PerPage:  10,
		Selected: make(map[string]bool),
	}

	ss := &stepState{
		URL:           url,
		MediaInfo:     info,
		PlaylistState: state,
	}
	h.setUserStepState(chatID, ss)

	h.sendMediaPreview(ctx, chatID, info)

	kb := playlistNavKeyboard(state, 0)
	h.sendWithKB(ctx, chatID, fmt.Sprintf("Playlist: %s (%d videos)\n\nSelect videos to download:", info.Title, info.PlaylistCount), kb)
}

func (h *Handler) getPlaylistState(chatID int64) *domain.PlaylistState {
	ss := h.getUserStepState(chatID)
	if ss == nil {
		return nil
	}
	return ss.PlaylistState
}

func (h *Handler) handlePlaylistPage(ctx context.Context, chatID int64, msgID int, userID int64, pageStr string) {
	state := h.getPlaylistState(chatID)
	if state == nil {
		return
	}
	page, err := strconv.Atoi(pageStr)
	if err != nil {
		return
	}
	totalPages := (len(state.Entries) + state.PerPage - 1) / state.PerPage
	if page < 0 || page >= totalPages {
		return
	}
	state.Page = page

	selectedCount := countSelected(state)
	kb := playlistNavKeyboard(state, selectedCount)
	ss := h.getUserStepState(chatID)
	title := ""
	if ss != nil {
		title = ss.MediaInfo.Title
	}
	h.editText(ctx, chatID, msgID, fmt.Sprintf("Playlist: %s (%d videos)", title, len(state.Entries)), &kb)
}

func (h *Handler) handlePlaylistEntry(ctx context.Context, chatID int64, msgID int, userID int64, entryID string) {
	state := h.getPlaylistState(chatID)
	if state == nil {
		return
	}
	state.Selected[entryID] = !state.Selected[entryID]

	selectedCount := countSelected(state)
	kb := playlistNavKeyboard(state, selectedCount)
	ss := h.getUserStepState(chatID)
	title := ""
	if ss != nil {
		title = ss.MediaInfo.Title
	}
	h.editText(ctx, chatID, msgID, fmt.Sprintf("Playlist: %s (%d videos)", title, len(state.Entries)), &kb)
}

func (h *Handler) handlePlaylistSelectAll(ctx context.Context, chatID int64, msgID int, userID int64) {
	state := h.getPlaylistState(chatID)
	if state == nil {
		return
	}

	allSelected := true
	for _, e := range state.Entries {
		if !state.Selected[e.ID] {
			allSelected = false
			break
		}
	}
	for _, e := range state.Entries {
		state.Selected[e.ID] = !allSelected
	}

	selectedCount := 0
	if !allSelected {
		selectedCount = len(state.Entries)
	}
	kb := playlistNavKeyboard(state, selectedCount)
	ss := h.getUserStepState(chatID)
	title := ""
	if ss != nil {
		title = ss.MediaInfo.Title
	}
	h.editText(ctx, chatID, msgID, fmt.Sprintf("Playlist: %s (%d videos)", title, len(state.Entries)), &kb)
}

func (h *Handler) handlePlaylistConfirm(ctx context.Context, chatID int64, msgID int, userID int64) {
	state := h.getPlaylistState(chatID)
	if state == nil {
		return
	}

	var selected []domain.PlaylistEntry
	for _, e := range state.Entries {
		if state.Selected[e.ID] {
			selected = append(selected, e)
		}
	}
	if len(selected) == 0 {
		h.editText(ctx, chatID, msgID, "No videos selected.", nil)
		return
	}

	h.clearStepState(chatID)
	h.editText(ctx, chatID, msgID, fmt.Sprintf("Downloading %d videos sequentially...", len(selected)), nil)

	for i, entry := range selected {
		h.sendText(ctx, chatID, fmt.Sprintf("Downloading (%d/%d): %s", i+1, len(selected), entry.Title))

		info, err := h.YtDlp.GetMediaInfo(entry.URL)
		if err != nil {
			h.sendText(ctx, chatID, fmt.Sprintf("Failed: %s", err.Error()))
			continue
		}

		prefs, prefErr := h.Repo.GetOrCreatePreferences(userID)
		if prefErr != nil {
			prefs = &domain.UserPreferences{
				DefaultMediaType:   domain.MediaTypeVideoAudio,
				DefaultAudioFormat: "best",
				DefaultVideoFormat: "best",
			}
		}

		formatID := prefs.DefaultVideoFormat
		if prefs.DefaultMediaType == domain.MediaTypeAudio {
			formatID = prefs.DefaultAudioFormat
		}
		format := &domain.Format{ID: formatID}
		for _, f := range info.Formats {
			if f.ID == formatID {
				format = &f
				break
			}
		}

		dlCtx, dlCancel := context.WithCancel(context.Background())

		job := &domain.DownloadJob{
			ID:             h.generateJobID(),
			UserID:         userID,
			ChatID:         chatID,
			URL:            entry.URL,
			MediaType:      prefs.DefaultMediaType,
			SelectedFormat: format,
			Language:       prefs.DefaultLanguage,
			Status:         domain.StatusDownloading,
			Title:          entry.Title,
			FileSize:       format.Filesize,
			Done:           make(chan struct{}),
		}

		h.setActiveJob(userID, job)
		h.setCancelFunc(userID, dlCancel)

		h.runDownload(dlCtx, job)

		// runDownload is synchronous — it blocks until the download completes.
		// The Done channel is closed inside runDownload when it exits.
		// No busy-polling needed.
	}

	h.sendText(ctx, chatID, "All playlist downloads completed.")
}

func countSelected(state *domain.PlaylistState) int {
	count := 0
	for _, s := range state.Selected {
		if s {
			count++
		}
	}
	return count
}