import { ChangeDetectionStrategy, Component, DestroyRef, OnInit, computed, inject, signal } from '@angular/core';
import { CommonModule } from '@angular/common';
import { FormBuilder, ReactiveFormsModule, Validators } from '@angular/forms';
import { takeUntilDestroyed } from '@angular/core/rxjs-interop';
import { AdminService, GeneralSettings, ThemeView } from '../../core/services/admin.service';
import { BootstrapService } from '../../core/services/bootstrap.service';
import { MarkdownService } from '../../core/services/markdown.service';
import { AdminCategoriesComponent } from './categories/categories.component';
import {
  deriveEventState,
  endAfterStartValidator,
  normalizePageTitle,
  pageTitleMessage,
  toDatetimeLocal,
  toIsoUtc,
} from './general.pure';

@Component({
  selector: 'app-admin-general',
  standalone: true,
  changeDetection: ChangeDetectionStrategy.OnPush,
  imports: [CommonModule, ReactiveFormsModule, AdminCategoriesComponent],
  styles: [`
    .general-section { display: flex; flex-direction: column; gap: 16px; }
    .form-grid { display: grid; grid-template-columns: 200px 1fr; gap: 12px; align-items: start; }
    .markdown-preview {
      border: 1px solid var(--color-secondary, #ccc);
      padding: 8px;
      border-radius: var(--radius-sm, 4px);
      background: var(--color-surface, #fff);
      min-height: 80px;
    }
    .event-state-running { color: var(--color-success, #0a0); }
    .event-state-countdown { color: var(--color-warning, #fa0); }
    .event-state-stopped { color: var(--color-danger, #f00); }
    .event-state-unconfigured { color: var(--color-secondary, #888); }
    .field-error { color: var(--color-danger, #f00); font-size: 12px; }
  `],
  template: `
    <section class="general-section" data-testid="admin-general">
      <h2>General settings</h2>

      @if (loading()) {
        <p data-testid="general-loading">Loading settings...</p>
      } @else if (loadError()) {
        <p data-testid="general-error" class="field-error">{{ loadError() }}</p>
      } @else {
        <form [formGroup]="form" (ngSubmit)="onSubmit()" data-testid="general-form">
          <div class="form-grid">
            <label for="pageTitle">Page title</label>
            <div>
              <input id="pageTitle" type="text" formControlName="pageTitle" data-testid="general-pageTitle" />
              @if (showPageTitleError()) {
                <div class="field-error" data-testid="general-pageTitle-error">{{ pageTitleMessage() }}</div>
              }
            </div>

            <label for="logo">Logo</label>
            <div>
              <input
                id="logo"
                type="file"
                accept="image/*"
                (change)="onLogoFileChange($event)"
                data-testid="general-logo-file"
              />
              @if (form.controls.logo.value) {
                <div style="font-size: 12px; opacity: 0.7;" data-testid="general-logo-current">
                  Current: {{ form.controls.logo.value }}
                </div>
              }
              @if (uploadingLogo()) {
                <span data-testid="general-logo-uploading">Uploading…</span>
              }
              @if (logoUploadError()) {
                <span class="field-error" data-testid="general-logo-error">{{ logoUploadError() }}</span>
              }
              <!-- Hidden bound input so the existing reactive-form contract is preserved;
                   the publicUrl returned from the upload lands here and is what save() submits. -->
              <input type="hidden" formControlName="logo" data-testid="general-logo" />
            </div>

            <label for="themeKey">Global theme</label>
            <div>
              <select id="themeKey" formControlName="themeKey" data-testid="general-themeKey">
                @for (t of themes(); track t.id) {
                  <option [value]="t.key">{{ t.name }}</option>
                }
              </select>
            </div>

            <label for="eventStartUtc">Event start (UTC)</label>
            <div>
              <input id="eventStartUtc" type="datetime-local" formControlName="eventStartUtc" data-testid="general-eventStart" />
            </div>

            <label for="eventEndUtc">Event end (UTC)</label>
            <div>
              <input id="eventEndUtc" type="datetime-local" formControlName="eventEndUtc" data-testid="general-eventEnd" />
              @if (form.controls.eventEndUtc.touched && form.error?.['endBeforeStart']) {
                <div class="field-error" data-testid="general-endBeforeStart">Event end must be after event start.</div>
              }
            </div>

            <label for="defaultChallengeIp">Default challenge IP</label>
            <div>
              <input id="defaultChallengeIp" type="text" formControlName="defaultChallengeIp" data-testid="general-defaultIp" />
            </div>

            <label for="registrationsEnabled">Enable registrations</label>
            <div>
              <input
                id="registrationsEnabled"
                type="checkbox"
                formControlName="registrationsEnabled"
                data-testid="general-registrations"
              />
            </div>

            <label>Welcome description</label>
            <div>
              <textarea
                formControlName="welcomeMarkdown"
                rows="6"
                cols="60"
                data-testid="general-welcome"
              ></textarea>
              <div
                class="markdown-preview"
                data-testid="general-welcome-preview"
                [innerHTML]="previewHtml()"
              ></div>
            </div>

            <label>Event controls</label>
            <div>
              <button type="button" disabled data-testid="general-event-toggle">
                {{ eventStateLabel() }} (derived from timestamps)
              </button>
              <p style="font-size:12px; opacity:0.7;">
                State is derived from the configured UTC timestamps above. Adjust Event End to "stop" the event; move Event Start into the past and Event End into the future to "start" it.
              </p>
            </div>
          </div>

          <div style="margin-top: 16px;">
            <button type="submit" [disabled]="submitting() || form.invalid" data-testid="general-save">Save</button>
            @if (saveError()) {
              <span class="field-error" data-testid="general-save-error">{{ saveError() }}</span>
            }
            @if (saveOk()) {
              <span data-testid="general-save-ok">Saved.</span>
            }
          </div>
        </form>
      }

      <app-admin-categories />
    </section>
  `,
})
export class AdminGeneralComponent implements OnInit {
  private readonly fb = inject(FormBuilder);
  private readonly admin = inject(AdminService);
  private readonly bootstrap = inject(BootstrapService);
  private readonly markdown = inject(MarkdownService);
  private readonly destroyRef = inject(DestroyRef);

  readonly loading = signal(true);
  readonly loadError = signal<string | null>(null);
  readonly submitting = signal(false);
  readonly saveError = signal<string | null>(null);
  readonly saveOk = signal(false);
  readonly themes = signal<ThemeView[]>([]);
  readonly uploadingLogo = signal(false);
  readonly logoUploadError = signal<string | null>(null);

  private readonly pageTitleValue = signal<string>('');
  private readonly pageTitleInvalid = signal<boolean>(false);
  private readonly pageTitleTouchedOrDirty = signal<boolean>(false);

  readonly form = this.fb.nonNullable.group(
    {
      pageTitle: this.fb.nonNullable.control('', [Validators.required, Validators.maxLength(120), this.pageTitleNotBlankValidator()]),
      logo: this.fb.nonNullable.control(''),
      welcomeMarkdown: this.fb.nonNullable.control(''),
      themeKey: this.fb.nonNullable.control('classic'),
      eventStartUtc: this.fb.nonNullable.control(''),
      eventEndUtc: this.fb.nonNullable.control(''),
      defaultChallengeIp: this.fb.nonNullable.control('', [Validators.required]),
      registrationsEnabled: this.fb.nonNullable.control(false),
    },
    { validators: endAfterStartValidator },
  );

  readonly previewHtml = signal<string>('');

  readonly eventStateLabel = computed(() => {
    const startRaw = this.form.controls.eventStartUtc.value;
    const endRaw = this.form.controls.eventEndUtc.value;
    const state = deriveEventState(startRaw, endRaw);
    return state.toUpperCase();
  });

  readonly showPageTitleError = computed(
    () => this.pageTitleTouchedOrDirty() && this.pageTitleInvalid(),
  );

  readonly pageTitleMessage = computed(() =>
    pageTitleMessage(this.pageTitleValue(), this.form.controls.pageTitle.errors),
  );

  constructor() {
    this.form.controls.welcomeMarkdown.valueChanges
      .pipe(takeUntilDestroyed(this.destroyRef))
      .subscribe((v) => this.previewHtml.set(this.markdown.render(v)));

    const pt = this.form.controls.pageTitle;
    this.pageTitleValue.set(pt.value);
    this.pageTitleInvalid.set(pt.invalid);
    this.pageTitleTouchedOrDirty.set(pt.touched || pt.dirty);
    pt.valueChanges
      .pipe(takeUntilDestroyed(this.destroyRef))
      .subscribe((v) => {
        this.pageTitleValue.set(v);
        this.pageTitleTouchedOrDirty.set(pt.touched || pt.dirty);
      });
    pt.statusChanges
      .pipe(takeUntilDestroyed(this.destroyRef))
      .subscribe(() => {
        this.pageTitleInvalid.set(pt.invalid);
        this.pageTitleTouchedOrDirty.set(pt.touched || pt.dirty);
      });
  }

  async ngOnInit(): Promise<void> {
    try {
      const [settings, themes] = await Promise.all([
        this.admin.getGeneralSettings(),
        this.admin.listAdminThemes(),
      ]);
      this.applySettings(settings);
      this.themes.set(themes);
      this.previewHtml.set(this.markdown.render(settings.welcomeMarkdown));
      this.loading.set(false);
    } catch (e: any) {
      this.loadError.set(e?.error?.message ?? e?.message ?? 'Failed to load settings');
      this.loading.set(false);
    }
  }

  private pageTitleNotBlankValidator(): (ctrl: { value: string | null }) => { whitespace: true } | null {
    return (ctrl) => {
      const value = ctrl?.value ?? '';
      if (value.length === 0) return null;
      if (value.trim().length === 0) return { whitespace: true };
      return null;
    };
  }

  private applySettings(s: GeneralSettings): void {
    this.form.patchValue({
      pageTitle: s.pageTitle,
      logo: s.logo,
      welcomeMarkdown: s.welcomeMarkdown,
      themeKey: s.themeKey,
      eventStartUtc: toDatetimeLocal(s.eventStartUtc),
      eventEndUtc: toDatetimeLocal(s.eventEndUtc),
      defaultChallengeIp: s.defaultChallengeIp,
      registrationsEnabled: s.registrationsEnabled,
    });
    this.form.controls.pageTitle.markAsUntouched();
    this.form.controls.pageTitle.markAsPristine();
    this.pageTitleTouchedOrDirty.set(false);
  }

  async onSubmit(): Promise<void> {
    if (this.form.invalid) {
      this.form.markAllAsTouched();
      return;
    }
    this.submitting.set(true);
    this.saveError.set(null);
    this.saveOk.set(false);
    try {
      const v = this.form.getRawValue();
      const updated = await this.admin.updateGeneralSettings({
        pageTitle: normalizePageTitle(v.pageTitle),
        logo: v.logo,
        welcomeMarkdown: v.welcomeMarkdown,
        themeKey: v.themeKey,
        eventStartUtc: toIsoUtc(v.eventStartUtc),
        eventEndUtc: toIsoUtc(v.eventEndUtc),
        defaultChallengeIp: v.defaultChallengeIp,
        registrationsEnabled: v.registrationsEnabled,
      });
      this.applySettings(updated);
      await this.bootstrap.refresh();
      this.saveOk.set(true);
    } catch (e: any) {
      this.saveError.set(e?.error?.message ?? e?.message ?? 'Failed to save');
    } finally {
      this.submitting.set(false);
    }
  }

  async onLogoFileChange(ev: Event): Promise<void> {
    const input = ev.target as HTMLInputElement;
    const file = input.files?.[0];
    if (!file) return;
    this.uploadingLogo.set(true);
    this.logoUploadError.set(null);
    try {
      const res = await this.admin.uploadLogo(file);
      this.form.controls.logo.setValue(res.publicUrl);
    } catch (e: any) {
      this.logoUploadError.set(e?.error?.message ?? e?.message ?? 'Logo upload failed');
    } finally {
      this.uploadingLogo.set(false);
    }
  }
}