// itemDelegate is a compact single-line list renderer for media items: a
// media-type icon, the title, and a right-aligned meta column (year · duration ·
// watched). It replaces bubbles' two-line default delegate so the browser reads
// like a tidy table.
package tui

import (
	"fmt"
	"io"
	"strings"

	"github.com/charmbracelet/bubbles/list"
	tea "github.com/charmbracelet/bubbletea"
	"github.com/charmbracelet/lipgloss"

	"tsplay/internal/api"
)

type itemDelegate struct{ st styles }

func newItemDelegate(st styles) itemDelegate { return itemDelegate{st: st} }

func (d itemDelegate) Height() int                         { return 1 }
func (d itemDelegate) Spacing() int                        { return 0 }
func (d itemDelegate) Update(tea.Msg, *list.Model) tea.Cmd { return nil }

func (d itemDelegate) Render(w io.Writer, m list.Model, index int, raw list.Item) {
	it, ok := raw.(listItem)
	if !ok {
		return
	}
	selected := index == m.Index()

	icon := cell(mediaIcon(it.item), 2)
	title := rowTitle(it.item)
	meta := rowMeta(it.item)

	cursor := "  "
	if selected {
		cursor = d.st.accent.Render("▸ ")
	}

	width := m.Width()
	if width <= 0 {
		width = 80
	}
	// Layout: cursor(2) + icon(2) + " " + title + gap + meta + 1 right margin.
	fixed := 2 + lipgloss.Width(icon) + 1 + lipgloss.Width(meta) + 1
	titleBudget := width - fixed
	if lipgloss.Width(title) > titleBudget {
		title = truncate(title, titleBudget)
	}
	gap := width - fixed - lipgloss.Width(title)
	if gap < 0 {
		gap = 0
	}

	titleR := title
	if selected {
		titleR = d.st.accent.Render(title)
	}
	row := cursor + icon + " " + titleR + strings.Repeat(" ", gap) + d.st.muted.Render(meta)
	fmt.Fprint(w, row)
}

// Nerd Font Material Design icon glyphs (nf-md-*), matching the family Omarchy
// uses in waybar/walker. Defined by codepoint so the source bytes can't be
// mangled by an editor or terminal. These are single display-width.
const (
	iconMovie    = "\U000f07de" // nf-md-movie_open
	iconTV       = "\U000f082b" // nf-md-television_classic
	iconFolder   = "\U000f024b" // nf-md-folder
	iconEpisode  = "\U000f0fce" // nf-md-movie_play
	iconMusic    = "\U000f075a" // nf-md-music
	iconAlbum    = "\U000f0025" // nf-md-album
	iconArtist   = "\U000f0803" // nf-md-account_music
	iconMusicBox = "\U000f0223" // nf-md-music_box (music library)
	iconLibrary  = "\U000f0253" // nf-md-folder_multiple (generic library)
	iconFile     = "\U000f0224" // nf-md-file (plain leaf)
)

// IconLegend returns the (label, glyph) pairs tsplay uses, for the `--icons`
// debug command so the user can confirm their terminal font renders them.
func IconLegend() [][2]string {
	return [][2]string{
		{"movie", iconMovie},
		{"tv / series", iconTV},
		{"season / folder", iconFolder},
		{"episode", iconEpisode},
		{"audio track", iconMusic},
		{"album", iconAlbum},
		{"artist", iconArtist},
		{"music library", iconMusicBox},
		{"generic library", iconLibrary},
		{"file", iconFile},
	}
}

// mediaIcon picks a Nerd Font glyph for an item's type (or its library's
// collection type, or a generic folder/leaf glyph).
func mediaIcon(it api.Item) string {
	switch it.Type {
	case "Movie":
		return iconMovie
	case "Series":
		return iconTV
	case "Season":
		return iconFolder
	case "Episode":
		return iconEpisode
	case "Audio":
		return iconMusic
	case "MusicAlbum":
		return iconAlbum
	case "MusicArtist":
		return iconArtist
	case "CollectionFolder", "UserView":
		switch it.CollectionType {
		case "movies":
			return iconMovie
		case "tvshows":
			return iconTV
		case "music":
			return iconMusicBox
		default:
			return iconLibrary
		}
	}
	if it.IsFolder {
		return iconFolder
	}
	return iconFile
}

// rowTitle is the left text for a row: episode/track numbering where it helps,
// otherwise the bare name (year lives in the meta column).
func rowTitle(it api.Item) string {
	switch it.Type {
	case "Episode":
		if it.ParentIndexNumber > 0 && it.IndexNumber > 0 {
			return fmt.Sprintf("S%02dE%02d  %s", it.ParentIndexNumber, it.IndexNumber, it.Name)
		}
		if it.IndexNumber > 0 {
			return fmt.Sprintf("%d.  %s", it.IndexNumber, it.Name)
		}
	case "Audio":
		if it.IndexNumber > 0 {
			return fmt.Sprintf("%d.  %s", it.IndexNumber, it.Name)
		}
	}
	return it.Name
}

// rowMeta is the right-aligned column: "(year)  1h 23m  ✓".
func rowMeta(it api.Item) string {
	var parts []string
	if it.ProductionYear > 0 && (it.Type == "Movie" || it.Type == "Series") {
		parts = append(parts, fmt.Sprintf("(%d)", it.ProductionYear))
	}
	if d := formatDuration(it.RunTimeTicks); d != "" {
		parts = append(parts, d)
	}
	if it.UserData.Played {
		parts = append(parts, "✓")
	} else if it.UserData.PlayedPercentage > 1 {
		parts = append(parts, fmt.Sprintf("%.0f%%", it.UserData.PlayedPercentage))
	}
	return strings.Join(parts, "  ")
}

// cell pads s on the right so it occupies exactly w display columns. This keeps
// the title column aligned even when a terminal measures an emoji as one cell
// instead of two.
func cell(s string, w int) string {
	if gap := w - lipgloss.Width(s); gap > 0 {
		return s + strings.Repeat(" ", gap)
	}
	return s
}

// truncate shortens s to at most max display columns, appending an ellipsis.
func truncate(s string, max int) string {
	if max <= 0 {
		return ""
	}
	if lipgloss.Width(s) <= max {
		return s
	}
	var b strings.Builder
	for _, r := range s {
		if lipgloss.Width(b.String()+string(r))+1 > max {
			break
		}
		b.WriteRune(r)
	}
	return b.String() + "…"
}