import {
  Component,
  ElementRef,
  EventEmitter,
  HostListener,
  Input,
  OnChanges,
  OnDestroy,
  Output,
  SimpleChanges,
} from '@angular/core';
import { CommonModule } from '@angular/common';
import { A11yModule } from '@angular/cdk/a11y';

export type ModalSize = 'sm' | 'md' | 'lg' | 'xl' | '2xl' | 'full';
export type ModalVariant = 'default' | 'primary' | 'danger' | 'warning' | 'success' | 'info';
export type ModalPosition = 'center' | 'top';

/**
 * Professional, reusable modal dialog component.
 *
 * Fully integrated with the application theme (supports Light/Dark mode via CSS tokens).
 * Uses @angular/cdk's A11yModule (cdkTrapFocus) for keyboard accessibility and focus trapping.
 *
 * Features:
 *   - Responsive sizing: 'sm' | 'md' | 'lg' | 'xl' | '2xl' | 'full'
 *   - Semantic variants: 'default' | 'primary' | 'danger' | 'warning' | 'success' | 'info'
 *   - Title, subtitle, and badge icon support
 *   - Custom content projection via [modal-header], [modal-body], and [modal-footer]
 *   - Smooth backdrop fade and panel scale transitions
 *   - Accessible Esc and backdrop click dismissing
 *   - Automatic background scroll-lock management
*/

@Component({
  selector: 'app-modal',
  imports: [CommonModule, A11yModule],
  templateUrl: './modal.component.html',
  styleUrl: './modal.component.scss',
})
export class ModalComponent implements OnChanges, OnDestroy {
  @Input() isOpen = false;
  @Input() title = '';
  @Input() subtitle?: string;
  @Input() iconClass?: string;
  @Input() variant: ModalVariant = 'default';
  @Input() size: ModalSize = 'md';
  @Input() position: ModalPosition = 'center';
  @Input() scrollable = true;
  @Input() closeOnBackdropClick = true;
  @Input() closeOnEsc = true;
  @Input() showCloseButton = true;
  /** Set false when you don't project any modal-footer content to omit the bottom action bar. */
  @Input() showFooter = true;

  @Output() closed = new EventEmitter<void>();
  @Output() opened = new EventEmitter<void>();

  private previouslyFocusedElement: HTMLElement | null = null;
  private originalBodyOverflow = '';

  constructor(private hostRef: ElementRef<HTMLElement>) {}

  ngOnChanges(changes: SimpleChanges): void {
    if (!changes['isOpen']) {
      return;
    }

    if (this.isOpen) {
      this.previouslyFocusedElement = document.activeElement as HTMLElement;
      this.originalBodyOverflow = document.body.style.overflow;
      document.body.style.overflow = 'hidden';
      this.opened.emit();
    } else {
      this.unlockBodyScroll();
      this.previouslyFocusedElement?.focus?.();
    }
  }

  ngOnDestroy(): void {
    if (this.isOpen) {
      this.unlockBodyScroll();
    }
  }

  private unlockBodyScroll(): void {
    document.body.style.overflow = this.originalBodyOverflow || '';
  }

  @HostListener('document:keydown.escape')
  onEscKey(): void {
    if (this.isOpen && this.closeOnEsc) {
      this.close();
    }
  }

  onBackdropClick(): void {
    if (this.closeOnBackdropClick) {
      this.close();
    }
  }

  close(): void {
    this.closed.emit();
  }

  get sizeClass(): string {
    switch (this.size) {
      case 'sm':
        return 'modal-panel--sm';
      case 'lg':
        return 'modal-panel--lg';
      case 'xl':
        return 'modal-panel--xl';
      case '2xl':
        return 'modal-panel--2xl';
      case 'full':
        return 'modal-panel--full';
      default:
        return 'modal-panel--md';
    }
  }

  get positionClass(): string {
    return this.position === 'top' ? 'items-start pt-12 md:pt-16' : 'items-center';
  }
}