import { Component } from '@angular/core';
import type { Resource } from '@angular/core';
import { HeadingComponent } from '@shared/ui/heading/heading.component';
import { ASYNC } from '@shared/ui/async/async.component';
import { SkeletonComponent } from '@shared/ui/skeleton/skeleton.component';
import { ConceptCardComponent } from './concept-card.component';
import { SNIPPETS } from './snippets.generated';
import { highlightTs } from './highlight-ts';

/** Minimal fake Resource so <app-async> can be driven through every state without HTTP. */
function fakeResource<T>(status: string, value?: T, error?: Error): Resource<T> {
  return {
    value: () => value as T,
    status: () => status,
    error: () => error,
    hasValue: () => value !== undefined,
    reload: () => {},
  } as unknown as Resource<T>;
}

/** Section 2: RemoteData fold. One value with four mutually exclusive states, instead of
    three loose booleans. Composition-only; owns its own fake resources. Each of the four
    demo states nests its own `<app-concept-card>` for its label — a plain `.tag` element
    written here would carry this section's scope, not the card's, and stay unstyled. */
@Component({
  selector: 'app-concepts-remote-data-section',
  imports: [HeadingComponent, ...ASYNC, SkeletonComponent, ConceptCardComponent],
  template: `
    <section class="app-section">
      <app-heading [level]="2">2 · RemoteData fold</app-heading>
      <p class="app-lead">
        Eén waarde met vier elkaar uitsluitende toestanden in plaats van drie losse booleans.
      </p>
      <div class="app-cols">
        <app-concept-card variant="good" tag="Vier toestanden, één molecuul">
          <div class="app-stack">
            <app-concept-card variant="plain" tag="Loading">
              <app-async [resource]="loadingRes"
                ><ng-template appAsyncLoaded let-v>{{ v }}</ng-template
                ><ng-template appAsyncLoading
                  ><app-skeleton [count]="2" height="1.2rem" [delay]="0" /></ng-template
              ></app-async>
            </app-concept-card>
            <app-concept-card variant="plain" tag="Empty">
              <app-async [resource]="emptyRes" [isEmpty]="isEmpty"
                ><ng-template appAsyncLoaded let-v>{{ v }}</ng-template></app-async
              >
            </app-concept-card>
            <app-concept-card variant="plain" tag="Failure">
              <app-async [resource]="errorRes"
                ><ng-template appAsyncLoaded let-v>{{ v }}</ng-template></app-async
              >
            </app-concept-card>
            <app-concept-card variant="plain" tag="Success">
              <app-async [resource]="successRes" [isEmpty]="isEmpty"
                ><ng-template appAsyncLoaded
                  ><ul>
                    @for (i of successRes.value(); track i) {
                      <li>{{ i }}</li>
                    }
                  </ul></ng-template
                ></app-async
              >
            </app-concept-card>
          </div>
        </app-concept-card>
        <app-concept-card
          variant="good"
          tag="De exhaustieve fold"
          [code]="code['fold']"
          [src]="src['fold']"
        >
          <p class="app-note">
            Een nieuwe variant toevoegen breekt de compile via <code>assertNever</code> tot je hem
            afhandelt.
          </p>
        </app-concept-card>
      </div>
    </section>
  `,
})
export class RemoteDataSection {
  isEmpty = (v: string[]) => !v || v.length === 0;

  loadingRes = fakeResource<string[]>('loading');
  emptyRes = fakeResource<string[]>('resolved', []);
  errorRes = fakeResource<string[]>('error', undefined, new Error('Demo'));
  successRes = fakeResource<string[]>('resolved', ['Huisartsgeneeskunde', 'Spoedeisende hulp']);

  protected readonly code: Record<string, string> = { fold: highlightTs(SNIPPETS['fold']) };
  protected readonly src: Record<string, string> = { fold: 'shared/application/remote-data.ts' };
}