import { type FederatedPointerEvent, Graphics, Text } from 'pixi.js';
import { Theme, textStyle } from '../Theme';
import { type Size, Widget } from '../Widget';
import { truncate } from './Label';

export interface ListItem {
  id: string;
  label: string;
  /** Small secondary text on the right (e.g. the asset type). */
  hint?: string;
  /** Left indent in levels (hierarchies). */
  depth?: number;
  /** Optional marker color drawn as a small square before the label. */
  swatch?: number;
}

/**
 * Single-select list of rows. Rows are rebuilt from `setItems()`; selection is by id so
 * it survives rebuilds. Emits select, activate (double-click / Enter) and context events.
 */
export class ListView extends Widget {
  private items: ListItem[] = [];
  private rows: Row[] = [];
  private selectedId: string | null = null;
  onSelect?: (id: string | null) => void;
  onActivate?: (id: string) => void;
  onContextMenu?: (id: string, globalX: number, globalY: number) => void;
  rowHeight = Theme.rowHeight;
  emptyText = 'Nothing here yet';
  private readonly emptyLabel = new Text({ text: '', style: textStyle('muted') });

  constructor() {
    super();
    this.focusable = true;
    this.addChild(this.emptyLabel);
    this.on('pointerdown', (e: FederatedPointerEvent) => {
      if (e.target === this) this.select(null);
    });
  }

  get selected(): string | null {
    return this.selectedId;
  }

  setItems(items: ListItem[]): void {
    this.items = items;
    for (const row of this.rows) row.destroy({ children: true });
    this.rows = items.map((item, index) => {
      const row = new Row(item, this.rowHeight);
      row.on('pointerdown', (e: FederatedPointerEvent) => {
        if (e.button === 2) {
          this.select(item.id);
          this.onContextMenu?.(item.id, e.global.x, e.global.y);
        } else {
          this.select(item.id);
          if (e.detail === 2) this.onActivate?.(item.id);
        }
      });
      row.position.set(0, index * this.rowHeight);
      this.addChild(row);
      return row;
    });
    if (this.selectedId && !items.some((i) => i.id === this.selectedId)) this.selectedId = null;
    this.layout();
    this.redraw();
  }

  select(id: string | null, silent = false): void {
    if (id === this.selectedId) return;
    this.selectedId = id;
    this.redraw();
    if (!silent) this.onSelect?.(id);
  }

  override measure(): Size {
    return { w: this.minWidth, h: Math.max(this.minHeight, this.items.length * this.rowHeight) };
  }

  override onKeyDown(event: KeyboardEvent): boolean {
    const index = this.items.findIndex((i) => i.id === this.selectedId);
    if (event.key === 'ArrowDown') {
      const next = this.items[Math.min(this.items.length - 1, index + 1)];
      if (next) this.select(next.id);
      return true;
    }
    if (event.key === 'ArrowUp') {
      const prev = this.items[Math.max(0, index - 1)];
      if (prev) this.select(prev.id);
      return true;
    }
    if (event.key === 'Enter' && this.selectedId) {
      this.onActivate?.(this.selectedId);
      return true;
    }
    return false;
  }

  override layout(): void {
    for (const row of this.rows) row.resize(this.w, this.rowHeight);
  }

  override redraw(): void {
    for (const row of this.rows) row.setSelected(row.item.id === this.selectedId, this.focused);
    this.emptyLabel.text = this.items.length === 0 ? this.emptyText : '';
    this.emptyLabel.position.set(Theme.padding, Math.round((this.rowHeight - this.emptyLabel.height) / 2));
  }
}

class Row extends Widget {
  private readonly bg = new Graphics();
  private readonly labelText = new Text({ text: '', style: textStyle('body') });
  private readonly hint = new Text({ text: '', style: textStyle('small') });
  private hovered = false;
  private selected = false;
  private listFocused = false;

  constructor(readonly item: ListItem, height: number) {
    super();
    this.cursor = 'pointer';
    this.minHeight = height;
    this.addChild(this.bg, this.labelText, this.hint);
    this.on('pointerover', () => { this.hovered = true; this.invalidate(); });
    this.on('pointerout', () => { this.hovered = false; this.invalidate(); });
  }

  setSelected(selected: boolean, listFocused: boolean): void {
    if (selected === this.selected && listFocused === this.listFocused) return;
    this.selected = selected;
    this.listFocused = listFocused;
    this.invalidate();
  }

  override redraw(): void {
    const c = Theme.colors;
    const indent = Theme.padding + (this.item.depth ?? 0) * 14;
    this.bg.clear();
    if (this.selected) this.bg.rect(0, 0, this.w, this.h).fill(this.listFocused ? c.selection : c.controlActive);
    else if (this.hovered) this.bg.rect(0, 0, this.w, this.h).fill(c.controlHover);
    let x = indent;
    if (this.item.swatch !== undefined) {
      this.bg.roundRect(x, (this.h - 12) / 2, 12, 12, 2).fill(this.item.swatch);
      this.bg.roundRect(x + 0.5, (this.h - 12) / 2 + 0.5, 11, 11, 2).stroke({ width: 1, color: c.border });
      x += 18;
    }
    this.hint.text = this.item.hint ?? '';
    const hintW = this.hint.text ? this.hint.width + Theme.padding : 0;
    this.labelText.text = truncate(this.item.label, this.labelText.style, this.w - x - hintW - Theme.padding);
    this.labelText.position.set(x, Math.round((this.h - this.labelText.height) / 2));
    this.hint.position.set(Math.round(this.w - Theme.padding - this.hint.width), Math.round((this.h - this.hint.height) / 2));
  }
}