import { CATEGORIES, getCategoryInfo } from './models.js';
import { saveItem, savePhoto, loadPhotos, updatePhoto, deletePhoto, blobToURL } from './store.js';
import { removeBackground, autoSegment } from './ml-client.js';
import { showSegmentReview } from './segment-review.js';
import { showPolygonSelector } from './polygon-select.js';
import { normalizeColors } from './color-normalize.js';
import { tagOp } from './diag.js';

let selectedCategory = 'princess';
let imageBlob = null;       // original photo
let croppedBlob = null;     // after polygon crop (or same as imageBlob if skipped)
let polygon = null;         // normalized polygon coords from selector
let segmentedBlob = null;   // after background removal
let previewURL = null;
let croppedURL = null;
let fullDrawingMode = false;

let photoURLs = []; // object URLs for gallery thumbnails

// Cap the gallery at the N most recent photos. Each thumbnail is an
// <img> that iOS may decode on scroll-into-view; even downscaled photos
// add up, and we don't need to show every photo ever taken.
const GALLERY_MAX = 10;

// Any photo bigger than this is almost certainly a legacy full-size
// capture from before downscalePhoto existed. We rewrite them in place
// on load so subsequent sessions don't pay the cost again.
const LEGACY_MIGRATE_BYTES = 800 * 1024;

async function migrateLegacyPhotos(photos) {
  for (const p of photos) {
    if (!p.imageBlob || p.imageBlob.size <= LEGACY_MIGRATE_BYTES) continue;
    tagOp(`migrate: ${Math.round(p.imageBlob.size / 1024)}KB photo`);
    try {
      const small = await downscalePhoto(p.imageBlob);
      if (small && small.size < p.imageBlob.size) {
        p.imageBlob = small;
        await updatePhoto(p);
      }
    } catch (err) {
      console.warn('[upload] photo migration failed', err);
    }
    // Yield so iOS gets a chance to reclaim the full-res decode buffer
    // before we touch the next one.
    await new Promise(r => setTimeout(r, 50));
  }
}

export async function initUpload() {
  tagOp('upload: init');
  const screen = document.getElementById('upload-screen');

  photoURLs.forEach(u => URL.revokeObjectURL(u));
  photoURLs = [];

  let photos = await loadPhotos();
  await migrateLegacyPhotos(photos);
  // Show only the most recent few; keep oldest photos in IDB (user can
  // still delete them explicitly via the × button after we re-render).
  photos = photos
    .slice()
    .sort((a, b) => (b.createdAt || 0) - (a.createdAt || 0))
    .slice(0, GALLERY_MAX);
  tagOp(`upload: ${photos.length} gallery photos`);

  screen.innerHTML = `
    <div class="upload-header">
      <a href="#/" class="back-btn">\u2190 Back</a>
      <h2>Add something new!</h2>
    </div>

    <div class="camera-zone">
      <input type="file" accept="image/*" capture="environment" id="camera-input" class="camera-input"/>
      <label for="camera-input" id="camera-label" class="camera-label">
        <span class="camera-icon">\u{1F4F8}</span>
        <span class="camera-text">Tap to photograph!</span>
      </label>
    </div>

    ${photos.length > 0 ? `
      <div class="photo-gallery">
        <p class="picker-label">Or use a previous photo</p>
        <div class="photo-gallery-scroll" id="photo-gallery">
          ${photos.map(p => {
            const url = blobToURL(p.imageBlob);
            photoURLs.push(url);
            return `
              <div class="photo-gallery-item" data-photo-id="${p.id}">
                <img src="${url}" class="photo-gallery-thumb" draggable="false"
                     loading="lazy" decoding="async"/>
                <button class="photo-gallery-delete" data-photo-id="${p.id}">\u00D7</button>
              </div>
            `;
          }).join('')}
        </div>
      </div>
    ` : ''}

    <button id="select-area-btn" class="pill select-area-btn" style="display:none">
      \u2702\uFE0F Select area
    </button>

    <div id="category-section" class="category-picker">
      <p class="picker-label">What kind?</p>
      <div class="category-grid" id="category-grid"></div>
    </div>

    <div class="name-input-wrap" id="name-wrap">
      <label for="asset-name">Name (optional)</label>
      <input id="asset-name" type="text" placeholder="Give it a name..." class="name-input"/>
    </div>

    <div class="upload-actions" id="upload-actions" style="display:none">
      <button id="submit-btn" class="big-button magic-btn">
        \u2728 Magic Time! \u2728
      </button>
      <button id="full-drawing-btn" class="pill">
        \u2728 Full Drawing (auto-split)
      </button>
    </div>

    <div id="upload-status"></div>
  `;

  buildCategoryGrid();
  bindEvents(photos);
  resetState();
}

function buildCategoryGrid() {
  const grid = document.getElementById('category-grid');
  grid.innerHTML = CATEGORIES.map(c => `
    <button class="category-btn ${c.id === selectedCategory ? 'selected' : ''}" data-cat="${c.id}">
      <span class="cat-emoji">${c.emoji}</span>
      <span class="cat-label">${c.label}</span>
    </button>
  `).join('');
}

// Modern phone cameras produce ~3000x4000 JPEGs. Fully decoded that's
// ~48 MB of RGBA pixels, and iOS holds it pinned for the lifetime of the
// file reference. We only need ~1280 on the long edge for everything
// downstream (OUTPUT_DIM=768 for save, MODNet preprocesses to short-edge
// 512 for inference, polygon selector and preview render well below this).
// Re-encoding as JPEG at 85% keeps the on-disk size tiny too.
async function downscalePhoto(file, maxLongEdge = 1280) {
  // We have to decode once to read dimensions. Close it immediately.
  const probe = await createImageBitmap(file);
  const { width: origW, height: origH } = probe;
  probe.close();

  if (Math.max(origW, origH) <= maxLongEdge) {
    return file; // already small enough, keep original
  }

  const ratio = maxLongEdge / Math.max(origW, origH);
  const w = Math.round(origW * ratio);
  const h = Math.round(origH * ratio);

  // Second decode directly at the target size — the big one is short-lived.
  const bitmap = await createImageBitmap(file, {
    resizeWidth: w,
    resizeHeight: h,
    resizeQuality: 'medium',
  });
  const canvas = new OffscreenCanvas(w, h);
  canvas.getContext('2d').drawImage(bitmap, 0, 0);
  bitmap.close();
  return canvas.convertToBlob({ type: 'image/jpeg', quality: 0.85 });
}

function selectImage(blob) {
  imageBlob = blob;
  croppedBlob = null;
  polygon = null;
  segmentedBlob = null;
  if (previewURL) URL.revokeObjectURL(previewURL);
  if (croppedURL) URL.revokeObjectURL(croppedURL);
  previewURL = URL.createObjectURL(blob);
  croppedURL = null;

  showPhotoPreview(previewURL);
  document.getElementById('select-area-btn').style.display = '';
  document.getElementById('upload-status').innerHTML = '';
  document.getElementById('upload-actions').style.display = '';
  updateSubmitState();
}

function bindEvents(photos) {
  // Category picker
  document.getElementById('category-grid').addEventListener('click', (e) => {
    const btn = e.target.closest('.category-btn');
    if (!btn) return;
    selectedCategory = btn.dataset.cat;
    document.querySelectorAll('.category-btn').forEach(b => b.classList.remove('selected'));
    btn.classList.add('selected');
  });

  // Camera input — downscale immediately so we never hold the full-res
  // camera JPEG, then save to gallery.
  document.getElementById('camera-input').addEventListener('change', async (e) => {
    const file = e.target.files[0];
    if (!file) return;
    tagOp(`capture: downscaling ${Math.round(file.size / 1024)}KB`);
    const resized = await downscalePhoto(file);
    tagOp(`capture: downscaled -> ${Math.round(resized.size / 1024)}KB`);
    // White-balance before saving so the gallery thumb, polygon preview
    // and eventual background-removal input all see the same image.
    const normalized = await normalizeColors(resized);
    await savePhoto(normalized);
    selectImage(normalized);
  });

  // Photo gallery — tap to reuse, X to delete
  const gallery = document.getElementById('photo-gallery');
  if (gallery) {
    gallery.addEventListener('click', async (e) => {
      const delBtn = e.target.closest('.photo-gallery-delete');
      if (delBtn) {
        e.stopPropagation();
        const id = delBtn.dataset.photoId;
        await deletePhoto(id);
        initUpload();
        return;
      }
      const item = e.target.closest('.photo-gallery-item');
      if (!item) return;
      const photo = photos.find(p => p.id === item.dataset.photoId);
      if (photo) {
        // Downscale is idempotent — no-op for photos saved after this fix,
        // catches any full-res photos left over from before.
        const resized = await downscalePhoto(photo.imageBlob);
        selectImage(resized);
      }
    });
  }

  // Select area
  document.getElementById('select-area-btn').addEventListener('click', handleSelectArea);

  // Name input
  document.getElementById('asset-name').addEventListener('input', updateSubmitState);

  // Submit -> segmentation
  document.getElementById('submit-btn').addEventListener('click', handleMagicTime);

  // Full drawing mode
  document.getElementById('full-drawing-btn').addEventListener('click', handleFullDrawing);
}

function showPhotoPreview(url, caption) {
  const label = document.getElementById('camera-label');
  label.innerHTML = `
    <img src="${url}" class="camera-preview"/>
    <span class="camera-retake">${caption || 'Tap to retake'}</span>
  `;
  label.className = 'camera-preview-label';
}

async function handleSelectArea() {
  if (!previewURL) return;

  const result = await showPolygonSelector(previewURL);
  if (!result) return;

  croppedBlob = result.imageBlob;
  polygon = result.polygon;
  if (croppedURL) URL.revokeObjectURL(croppedURL);
  croppedURL = URL.createObjectURL(croppedBlob);

  showPhotoPreview(previewURL, '\u2702\uFE0F Area selected \u2014 tap to retake photo');
  document.getElementById('select-area-btn').textContent = '\u2702\uFE0F Reselect area';
  updateSubmitState();
}

function updateSubmitState() {
  const btn = document.getElementById('submit-btn');
  if (btn) btn.disabled = !imageBlob;
}

async function handleMagicTime() {
  const name = document.getElementById('asset-name').value.trim();
  if (!imageBlob) return;

  const btn = document.getElementById('submit-btn');
  const status = document.getElementById('upload-status');

  btn.disabled = true;
  document.getElementById('upload-actions').style.display = 'none';

  status.innerHTML = `
    <div class="processing">
      <span class="crown-spin">\u{1F451}</span>
      <p id="seg-message">Removing the background!</p>
      <div id="seg-progress-bar" class="progress-bar"><div id="seg-progress-fill" class="progress-fill"></div></div>
      <p class="progress-hint">This might take a moment.</p>
    </div>
  `;

  // Re-normalize as a safety net for legacy gallery photos that were
  // captured before normalizeColors existed. Post-feature captures are
  // already normalized, so this is a fast idempotent pass.
  let skipBlob = croppedBlob || imageBlob;

  try {
    const normalized = await normalizeColors(imageBlob);
    if (!croppedBlob) skipBlob = normalized;
    let segResult = await removeBackground(normalized, (info) => {
      const msg = document.getElementById('seg-message');
      const fill = document.getElementById('seg-progress-fill');
      if (msg) msg.textContent = info.message;
      if (fill && info.progress != null) fill.style.width = `${info.progress}%`;
    });

    if (polygon && polygon.length >= 3) {
      segResult = await intersectSegmentationWithPolygon(segResult, polygon);
    }

    segmentedBlob = segResult;

    const segURL = URL.createObjectURL(segmentedBlob);
    const beforeURL = previewURL;
    status.innerHTML = `
      <div class="seg-preview">
        <p class="seg-preview-label">How does it look?</p>
        <div class="seg-comparison">
          <div class="seg-compare-item">
            <img src="${beforeURL}" class="seg-compare-img" alt="Before"/>
            <span>Before</span>
          </div>
          <div class="seg-compare-item">
            <img src="${segURL}" class="seg-compare-img checkerboard-bg" alt="After"/>
            <span>After</span>
          </div>
        </div>
        <div class="seg-actions">
          <button id="seg-approve" class="big-button">\u2705 Looks good!</button>
          <button id="seg-skip" class="pill">Save without removing</button>
          <button id="seg-retry" class="pill">Retake photo</button>
        </div>
      </div>
    `;

    document.getElementById('seg-approve').addEventListener('click', () => {
      tagOp('approve: clicked');
      saveAsset(name, segmentedBlob);
    });
    document.getElementById('seg-skip').addEventListener('click', () => {
      tagOp('skip: clicked');
      saveAsset(name, skipBlob);
    });
    document.getElementById('seg-retry').addEventListener('click', resetToCamera);

  } catch (err) {
    console.error('Segmentation failed:', err);
    status.innerHTML = `
      <div class="error-state">
        <p>Background removal didn't work this time.</p>
        <p class="error-detail">${err.message}</p>
        <div class="seg-actions">
          <button id="seg-skip-err" class="big-button">Save without removing</button>
          <button id="seg-retry-err" class="pill">Try again</button>
        </div>
      </div>
    `;
    document.getElementById('seg-skip-err').addEventListener('click', () => saveAsset(name, skipBlob));
    document.getElementById('seg-retry-err').addEventListener('click', () => {
      document.getElementById('upload-actions').style.display = '';
      btn.disabled = false;
      status.innerHTML = '';
    });
  }
}

async function handleFullDrawing() {
  if (!imageBlob) return;

  const btn = document.getElementById('full-drawing-btn');
  const status = document.getElementById('upload-status');

  document.getElementById('upload-actions').style.display = 'none';

  function showProgress(message, progress) {
    const msg = document.getElementById('seg-message');
    const fill = document.getElementById('seg-progress-fill');
    if (msg) msg.textContent = message;
    if (fill && progress != null) fill.style.width = `${progress}%`;
  }

  status.innerHTML = `
    <div class="processing">
      <span class="crown-spin">\u{1F451}</span>
      <p id="seg-message">Removing the background...</p>
      <div id="seg-progress-bar" class="progress-bar"><div id="seg-progress-fill" class="progress-fill"></div></div>
      <p class="progress-hint">This might take a moment.</p>
    </div>
  `;

  try {
    const bgRemoved = await removeBackground(imageBlob, (info) => {
      showProgress(info.message, info.progress * 0.4);
    });

    await new Promise(r => setTimeout(r, 200));

    showProgress('Finding all the parts...', 40);
    const segments = await autoSegment(bgRemoved, (info) => {
      const overall = 40 + (info.progress || 0) * 0.4;
      showProgress(info.message, overall);
    });

    if (segments.length === 0) {
      status.innerHTML = `
        <div class="error-state">
          <p>Couldn't find any distinct parts in this drawing.</p>
          <div class="seg-actions">
            <button id="fd-retry" class="pill">Try again</button>
          </div>
        </div>
      `;
      document.getElementById('fd-retry').addEventListener('click', () => {
        document.getElementById('upload-actions').style.display = '';
        status.innerHTML = '';
      });
      return;
    }

    showProgress('Ready for review!', 100);
    const bgRemovedURL = URL.createObjectURL(bgRemoved);
    const reviewResult = await showSegmentReview(bgRemovedURL, segments);
    URL.revokeObjectURL(bgRemovedURL);

    if (!reviewResult) {
      document.getElementById('upload-actions').style.display = '';
      status.innerHTML = '';
      return;
    }

    status.innerHTML = `
      <div class="processing">
        <span class="crown-spin">\u{1F451}</span>
        <p>Saving everything...</p>
      </div>
    `;

    let savedCount = 0;

    if (reviewResult.princess) {
      await saveItem({
        name: '',
        category: 'princess',
        imageBlob: reviewResult.princess.blob,
        scale: 0.8,
        zIndex: 2,
      });
      savedCount++;
    }

    for (const item of reviewResult.clothing) {
      const catInfo = getCategoryInfo(item.category);
      await saveItem({
        name: '',
        category: item.category,
        imageBlob: item.blob,
        scale: catInfo.scale || 0.5,
        zIndex: catInfo.zIndex,
      });
      savedCount++;
    }

    status.innerHTML = `
      <div class="success">
        <p class="success-text">\u2705 Saved ${savedCount} item${savedCount !== 1 ? 's' : ''}!</p>
        <a href="#/" class="big-button">Back to game</a>
        <button id="fd-another" class="pill">Segment another drawing</button>
      </div>
    `;

    document.getElementById('fd-another').addEventListener('click', resetToCamera);

  } catch (err) {
    console.error('Full drawing pipeline failed:', err);
    status.innerHTML = `
      <div class="error-state">
        <p>Something went wrong during segmentation.</p>
        <p class="error-detail">${err.message}</p>
        <div class="seg-actions">
          <button id="fd-retry-err" class="pill">Try again</button>
        </div>
      </div>
    `;
    document.getElementById('fd-retry-err').addEventListener('click', () => {
      document.getElementById('upload-actions').style.display = '';
      status.innerHTML = '';
    });
  }
}

function resetToCamera() {
  resetState();
  initUpload();
}

async function intersectSegmentationWithPolygon(segBlob, poly) {
  const bitmap = await createImageBitmap(segBlob);
  const fullW = bitmap.width;
  const fullH = bitmap.height;

  const pxPoly = poly.map(p => ({ x: p.x * fullW, y: p.y * fullH }));

  let minX = fullW, minY = fullH, maxX = 0, maxY = 0;
  for (const p of pxPoly) {
    minX = Math.min(minX, p.x);
    minY = Math.min(minY, p.y);
    maxX = Math.max(maxX, p.x);
    maxY = Math.max(maxY, p.y);
  }
  const pad = 4;
  minX = Math.max(0, Math.floor(minX) - pad);
  minY = Math.max(0, Math.floor(minY) - pad);
  maxX = Math.min(fullW, Math.ceil(maxX) + pad);
  maxY = Math.min(fullH, Math.ceil(maxY) + pad);
  const cropW = maxX - minX;
  const cropH = maxY - minY;

  const canvas = new OffscreenCanvas(cropW, cropH);
  const ctx = canvas.getContext('2d');

  ctx.beginPath();
  ctx.moveTo(pxPoly[0].x - minX, pxPoly[0].y - minY);
  for (let i = 1; i < pxPoly.length; i++) {
    ctx.lineTo(pxPoly[i].x - minX, pxPoly[i].y - minY);
  }
  ctx.closePath();
  ctx.clip();

  ctx.drawImage(bitmap, minX, minY, cropW, cropH, 0, 0, cropW, cropH);

  return canvas.convertToBlob({ type: 'image/png' });
}

async function saveAsset(name, blob) {
  tagOp('save: clicked');
  const status = document.getElementById('upload-status');
  status.innerHTML = `
    <div class="processing">
      <span class="crown-spin">\u{1F451}</span>
      <p>Saving!</p>
    </div>
  `;

  // iOS is likely still near the high-water mark from MODNet inference.
  // Drop the cropped intermediate (keep imageBlob/previewURL — the
  // "Select another from this photo" flow re-uses them) and give the
  // GC a moment before IndexedDB clones `blob` into a transaction.
  tagOp('save: freeing intermediates');
  croppedBlob = null;
  if (croppedURL) { URL.revokeObjectURL(croppedURL); croppedURL = null; }

  await new Promise(r => setTimeout(r, 100));

  try {
    const catInfo = getCategoryInfo(selectedCategory);
    tagOp(`save: writing to IDB (${Math.round(blob.size / 1024)}KB)`);
    await saveItem({
      name,
      category: selectedCategory,
      imageBlob: blob,
      scale: catInfo.scale || 0.5,
      zIndex: catInfo.zIndex,
    });
    tagOp('save: IDB done');

    status.innerHTML = `
      <div class="success">
        <p class="success-text">\u2705 All done!</p>
        <button id="another-from-photo" class="big-button">Select another from this photo</button>
        <a href="#/" class="pill">Back to game</a>
      </div>
    `;
    tagOp('save: success shown');

    document.getElementById('another-from-photo').addEventListener('click', () => {
      resetForAnotherSelection();
    });
  } catch (err) {
    tagOp(`save: error ${err.message}`);
    status.innerHTML = `
      <div class="error-state">
        <p>Oops! Something went wrong.</p>
        <p class="error-detail">${err.message}</p>
      </div>
    `;
  }
}

function resetForAnotherSelection() {
  const status = document.getElementById('upload-status');
  status.innerHTML = '';
  document.getElementById('upload-actions').style.display = '';
  document.getElementById('submit-btn').disabled = false;

  croppedBlob = null;
  polygon = null;
  segmentedBlob = null;
  if (croppedURL) URL.revokeObjectURL(croppedURL);
  croppedURL = null;

  document.getElementById('asset-name').value = '';

  showPhotoPreview(previewURL);
  document.getElementById('select-area-btn').style.display = '';
  document.getElementById('select-area-btn').textContent = '\u2702\uFE0F Select area';

  updateSubmitState();
}

function resetState() {
  selectedCategory = 'princess';
  imageBlob = null;
  croppedBlob = null;
  polygon = null;
  segmentedBlob = null;
  if (previewURL) URL.revokeObjectURL(previewURL);
  if (croppedURL) URL.revokeObjectURL(croppedURL);
  previewURL = null;
  croppedURL = null;
}