// SPDX-FileCopyrightText: 2025-2026 Lucio Lelii <lucio.lelii@isti.cnr.it> - ISTI-CNR
// SPDX-License-Identifier: AGPL-3.0-or-later
// Attribution term under AGPL-3.0 section 7(b): see LICENSE-ADDENDUM.

import { ChangeDetectionStrategy, Component, EventEmitter, Input, OnChanges, Output, SimpleChanges, signal } from '@angular/core';

export type NodeListFieldItem = {
  index: number;
  summary: string;
  /** Something the item can be opened to read in full, when it has one. */
  definition?: unknown | null;
};

/**
 * A node parameter that is a list: its name and how many items it has, the items themselves on
 * demand. Shared by every node that shows lists - blocks, the execution view, and containers once
 * one has a list parameter - so they all read and behave the same.
 *
 * <p>Starts closed. With no items there is nothing to open, and the add button is the way in; an
 * item added opens the list, so what was just added is there to see rather than only counted.
 */
@Component({
  selector: 'app-node-list-field',
  standalone: true,
  templateUrl: './node-list-field.html',
  styleUrl: './node-list-field.css',
  changeDetection: ChangeDetectionStrategy.OnPush
})
export class NodeListFieldComponent implements OnChanges {
  @Input({ required: true }) label = '';
  @Input() items: NodeListFieldItem[] = [];
  /** Read-only views - an execution - show the items and offer nothing to change them. */
  @Input() readonly = false;

  @Output() readonly add = new EventEmitter<void>();
  @Output() readonly edit = new EventEmitter<number>();
  @Output() readonly remove = new EventEmitter<number>();
  @Output() readonly view = new EventEmitter<unknown>();

  readonly expanded = signal(false);

  ngOnChanges(changes: SimpleChanges): void {
    const change = changes['items'];
    if (!change || change.firstChange) return;
    const before = Array.isArray(change.previousValue) ? change.previousValue.length : 0;
    const after = this.items?.length ?? 0;
    if (after > before) this.expanded.set(true);
    if (after === 0) this.expanded.set(false);
  }

  toggle(event: Event) {
    event.preventDefault();
    event.stopPropagation();
    if (!this.items.length) return;
    this.expanded.update((open) => !open);
  }

  emit<T>(emitter: EventEmitter<T>, value: T, event: Event) {
    event.preventDefault();
    event.stopPropagation();
    emitter.emit(value);
  }
}