import { booleanAttribute, Component, effect, ElementRef, inject, input, signal, viewChild } from '@angular/core';
import type { FloatPos } from '../../theme';
import { FloatingPanelController } from '../../theme';

export type TooltipPosition = 'top' | 'bottom' | 'left' | 'right';
export type TooltipAlign = 'start' | 'center' | 'end';

/**
 * 文字提示:用 ng-content 包裹触发元素,悬停/聚焦后延迟显示提示气泡。
 * align 控制 top/bottom 时的水平对齐。
 * autoFlip:当提示方向空间不足(如触发元素贴近视口顶部)时,自动翻转方向,避免被裁切。
 */
@Component({
  selector: 'ui-tooltip',
  imports: [],
  templateUrl: './tooltip.html',
  styleUrl: './tooltip.scss',
})
export class UiTooltip {
  /** 提示文案 */
  readonly content = input('');
  /** 提示方向 */
  readonly position = input<TooltipPosition>('top');
  /** 水平对齐(top/bottom 时生效):start 靠左 / center 居中 / end 靠右 */
  readonly align = input<TooltipAlign>('center');
  /** 悬停后显示的延迟(毫秒) */
  readonly delay = input(200);
  /** 空间不足时自动翻转方向 */
  readonly autoFlip = input(true, { transform: booleanAttribute });

  protected readonly visible = signal(false);
  /** 面板 fixed 定位坐标（null=未定位，面板先隐藏避免闪位） */
  protected readonly panelPos = signal<FloatPos | null>(null);

  /** 实际渲染方向(自动翻转后) */
  protected readonly effectivePosition = signal<TooltipPosition>('top');

  private readonly host = inject(ElementRef<HTMLElement>);
  private readonly panelEl = viewChild<ElementRef<HTMLElement>>('panel');
  private controller: FloatingPanelController | null = null;
  private timer: ReturnType<typeof setTimeout> | undefined;

  protected readonly tooltipClass =
    'pointer-events-none fixed z-[var(--z-popover)] whitespace-nowrap rounded-md bg-ink px-2.5 py-1.5 text-xs text-inverse shadow-pop animate-scale-in';

  constructor() {
    effect(() => {
      if (this.visible()) {
        this.panelPos.set(null);
        setTimeout(() => this.attachPanel(), 0);
      } else {
        this.controller?.destroy();
        this.controller = null;
        this.panelPos.set(null);
      }
    });
  }

  private attachPanel(): void {
    if (!this.visible()) return;
    const panel = this.panelEl()?.nativeElement;
    if (!panel) return;
    this.controller?.destroy();
    this.controller = new FloatingPanelController(this.host.nativeElement, panel, {
      side: this.effectivePosition(),
      align: this.align() === 'end' ? 'end' : 'start',
      centered: this.align() === 'center',
      gap: 8,
    });
    this.panelPos.set(this.controller.getPos());
  }

  show(): void {
    clearTimeout(this.timer);
    // 自动翻转:方向空间不足时反向,保证气泡不被视口边缘裁切
    let eff = this.position();
    if (this.autoFlip()) {
      const rect = this.host.nativeElement.getBoundingClientRect();
      const margin = 44;
      if (eff === 'top' && rect.top < margin) eff = 'bottom';
      else if (eff === 'bottom' && window.innerHeight - rect.bottom < margin) eff = 'top';
      else if (eff === 'left' && rect.left < margin) eff = 'right';
      else if (eff === 'right' && window.innerWidth - rect.right < margin) eff = 'left';
    }
    this.effectivePosition.set(eff);
    this.timer = setTimeout(() => this.visible.set(true), Math.max(0, this.delay()));
  }

  hide(): void {
    clearTimeout(this.timer);
    this.visible.set(false);
  }
}