/**
 * The preset builder.
 *
 * This composes a Klarbild recipe and shows what it would run — it does not
 * run anything. Generating on a public page would mean putting an API key on
 * that page and paying for every curious visitor, and the picture it produced
 * would tell you about the model rather than about Klarbild. What Klarbild
 * decides is the part this does show: which tasks, which exact target size,
 * and the preset you save once and reuse.
 *
 * The target pixels come from `engine/format.ts`, copied verbatim from the
 * application, so the numbers here are the numbers it would produce.
 */

import { resolveDimensions } from '../engine/format';

export interface PresetExample {
  name: string;
  tasks: string[];
  format: string;
  orientation: 'portrait' | 'landscape';
  ext?: string;
  note: string;
}

interface Labels {
  resultKeep: string;
  contourNeedsCutout: string;
  dpiLine: string;   // "{w} × {h} px at {dpi} dpi"
}

const ALL_TASKS = ['clean', 'cutout', 'format', 'contour'];

export function mountRecipe(root: HTMLElement, presets: PresetExample[], labels: Labels) {
  const state = {
    tasks: new Set(presets[0]?.tasks ?? ['clean']),
    format: presets[0]?.format ?? 'keep',
    orientation: (presets[0]?.orientation ?? 'landscape') as 'portrait' | 'landscape',
    ext: presets[0]?.ext ?? '',
    name: presets[0]?.name ?? '',
    note: presets[0]?.note ?? '',
  };

  const out = {
    result: root.querySelector<HTMLElement>('[data-r=result]')!,
    note: root.querySelector<HTMLElement>('[data-r=note]')!,
    recipe: root.querySelector<HTMLElement>('[data-r=recipe]')!,
  };

  function dims() {
    if (state.format === 'keep') return null;
    const customCm: [number, number] | undefined = state.format === 'sticker' ? [5, 5] : undefined;
    try {
      return resolveDimensions({ format: state.format, orientation: state.orientation, dpi: 300, customCm });
    } catch {
      return null;
    }
  }

  function render() {
    // Contour without Cut out is refused by the application, so the builder
    // refuses it too rather than composing a recipe that would be rejected.
    if (state.tasks.has('contour') && !state.tasks.has('cutout')) state.tasks.delete('contour');

    for (const b of root.querySelectorAll<HTMLButtonElement>('button[data-task]')) {
      const id = b.dataset.task!;
      b.setAttribute('aria-pressed', String(state.tasks.has(id)));
      b.disabled = id === 'contour' && !state.tasks.has('cutout');
    }
    for (const b of root.querySelectorAll<HTMLButtonElement>('button[data-orient]')) {
      b.setAttribute('aria-pressed', String(b.dataset.orient === state.orientation));
    }
    for (const b of root.querySelectorAll<HTMLButtonElement>('button[data-ext]')) {
      b.setAttribute('aria-pressed', String((b.dataset.ext || '') === state.ext));
    }
    const sel = root.querySelector<HTMLSelectElement>('#recipe-format');
    if (sel && sel.value !== state.format) sel.value = state.format;

    const d = dims();
    out.result.textContent = d
      ? labels.dpiLine.replace('{w}', String(d.w)).replace('{h}', String(d.h)).replace('{dpi}', '300')
      : labels.resultKeep;

    out.note.textContent = state.note;

    const recipe: Record<string, unknown> = {
      name: state.name || '…',
      tasks: ALL_TASKS.filter((t) => state.tasks.has(t)),
      output_format: state.format,
      orientation: state.orientation,
      crop_mode: 'crop',
      dpi: 300,
    };
    if (state.ext) recipe.output_ext = state.ext;
    if (state.tasks.has('contour')) recipe.contour_mm = 3;
    out.recipe.textContent = JSON.stringify(recipe, null, 2);
  }

  root.addEventListener('click', (e) => {
    const el = e.target as HTMLElement;
    const task = el.closest<HTMLButtonElement>('button[data-task]');
    if (task && !task.disabled) {
      const id = task.dataset.task!;
      state.tasks.has(id) ? state.tasks.delete(id) : state.tasks.add(id);
      state.name = '';
      state.note = '';
      return render();
    }
    const orient = el.closest<HTMLButtonElement>('button[data-orient]');
    if (orient) {
      state.orientation = orient.dataset.orient as 'portrait' | 'landscape';
      return render();
    }
    const ext = el.closest<HTMLButtonElement>('button[data-ext]');
    if (ext) {
      state.ext = ext.dataset.ext || '';
      return render();
    }
    const preset = el.closest<HTMLButtonElement>('button[data-preset]');
    if (preset) {
      const p = presets[Number(preset.dataset.preset)];
      state.tasks = new Set(p.tasks);
      state.format = p.format;
      state.orientation = p.orientation;
      state.ext = p.ext ?? '';
      state.name = p.name;
      state.note = p.note;
      for (const sib of root.querySelectorAll<HTMLButtonElement>('button[data-preset]')) {
        sib.setAttribute('aria-pressed', String(sib === preset));
      }
      return render();
    }
  });

  root.addEventListener('change', (e) => {
    const sel = e.target as HTMLSelectElement;
    if (sel.id === 'recipe-format') {
      state.format = sel.value;
      state.name = '';
      state.note = '';
      render();
    }
  });

  const first = root.querySelector<HTMLButtonElement>('button[data-preset="0"]');
  first?.setAttribute('aria-pressed', 'true');
  render();
}