import { escapeAttr } from './citations.js';

export function createAssistantImageStore() {
  var generatedImages = {};
  var generatedImageSeq = 0;
  var previewKeyHandler = null;

  function renderGeneratedImage(src, alt) {
    var id = 'img-' + (++generatedImageSeq);
    generatedImages[id] = src;
    return '<div class="assistant-generated-image"><img src="' + escapeAttr(src) + '" alt="' + escapeAttr(alt || 'Generated image') + '">' +
      '<div class="assistant-image-actions">' +
      '<button type="button" class="btn-sm btn-ghost" data-assistant-open-image="' + escapeAttr(id) + '"><i class="fas fa-expand"></i> Preview</button>' +
      '<button type="button" class="btn-sm btn-ghost" data-assistant-download-image="' + escapeAttr(id) + '"><i class="fas fa-download"></i> Download</button>' +
      '</div></div>';
  }

  function openImagePreview(id) {
    var src = generatedImages[id];
    if (!src) return;
    closeImagePreview();
    var modal = document.createElement('div');
    modal.className = 'assistant-image-modal';
    modal.setAttribute('role', 'dialog');
    modal.setAttribute('aria-modal', 'true');
    modal.innerHTML = '<div class="assistant-image-modal-card"><button type="button" class="assistant-image-modal-close" aria-label="Close">&times;</button><img src="' + escapeAttr(src) + '" alt="Generated clinical visual"><button type="button" class="assistant-image-modal-cancel">Close preview</button></div>';
    modal.addEventListener('click', function (event) {
      if (event.target === modal || event.target.closest('.assistant-image-modal-close') || event.target.closest('.assistant-image-modal-cancel')) closeImagePreview();
    });
    previewKeyHandler = function (event) { if (event.key === 'Escape') closeImagePreview(); };
    document.addEventListener('keydown', previewKeyHandler);
    document.body.appendChild(modal);
    document.body.classList.add('assistant-image-preview-open');
  }

  function closeImagePreview() {
    document.querySelectorAll('.assistant-image-modal').forEach(function (el) { el.remove(); });
    document.body.classList.remove('assistant-image-preview-open');
    if (previewKeyHandler) document.removeEventListener('keydown', previewKeyHandler);
    previewKeyHandler = null;
  }

  async function downloadImage(id) {
    var src = generatedImages[id];
    if (!src) return;
    try {
      if (await saveWithNativeShare(src)) return;
      if (isNativeApp()) {
        if (typeof window.showToast === 'function') window.showToast('Image saving is not available in this app build yet. Update the app and try again.', 'error');
        return;
      }
      await downloadWithBrowser(src);
    } catch (e) {
      if (typeof window.showToast === 'function') window.showToast(e.message || 'Image download failed', 'error');
    }
  }

  function clear() {
    generatedImages = {};
    closeImagePreview();
  }

  return {
    renderGeneratedImage: renderGeneratedImage,
    openImagePreview: openImagePreview,
    downloadImage: downloadImage,
    closeImagePreview: closeImagePreview,
    clear: clear
  };
}

async function saveWithNativeShare(src) {
  if (isNativeApp()) {
    if (await saveWithNativeImageBridge(src)) return true;
    return await saveWithCapacitorShare(src);
  }
  var webShare = await shareWithWebFile(src);
  if (webShare !== 'unavailable') return true;

  return await saveWithCapacitorShare(src);
}

async function saveWithNativeImageBridge(src) {
  if (!window.NativeFiles || typeof window.NativeFiles.saveImage !== 'function') return false;
  try {
    var base64 = await imageSourceToBase64(src);
    var name = 'clinical-visual-' + new Date().toISOString().replace(/[:.]/g, '-').slice(0, 19) + '.png';
    var result = String(window.NativeFiles.saveImage(name, base64) || '');
    if (result.indexOf('saved:') === 0) {
      if (typeof window.showToast === 'function') window.showToast('Image saved to Photos', 'success');
      return true;
    }
    if (result.indexOf('error:') === 0 && typeof window.showToast === 'function') {
      window.showToast(result.slice(6) || 'Native image save failed', 'error');
    }
  } catch (e) {
    if (typeof window.showToast === 'function') window.showToast(e.message || 'Native image save failed', 'error');
  }
  return false;
}

async function saveWithCapacitorShare(src) {
  var plugins = window.Capacitor && window.Capacitor.Plugins ? window.Capacitor.Plugins : null;
  if (!plugins) return false;
  if (!plugins.Filesystem && plugins.Share && !/^data:image\//i.test(src)) {
    try {
      await plugins.Share.share({ title: 'Clinical visual', text: 'Clinical Assistant generated visual', url: src, dialogTitle: 'Save or share clinical visual' });
      return true;
    } catch (e) { return isShareCancel(e); }
  }
  if (!plugins.Filesystem) return false;
  try {
    var base64 = await imageSourceToBase64(src);
    var name = 'clinical-visual-' + new Date().toISOString().replace(/[:.]/g, '-').slice(0, 19) + '.png';
    var saved = await plugins.Filesystem.writeFile({ path: name, data: base64, directory: 'CACHE' });
    if (plugins.Share && saved && saved.uri) {
      try {
        await plugins.Share.share({ title: 'Clinical visual', text: 'Clinical Assistant generated visual', url: saved.uri, dialogTitle: 'Save or share clinical visual' });
      } catch (e) {
        if (!isShareCancel(e)) throw e;
      }
    }
    if (typeof window.showToast === 'function') window.showToast('Image prepared', 'success');
    return true;
  } catch (e) {
    if (typeof window.showToast === 'function') window.showToast('Could not save with the app. Opening browser download instead.', 'error');
    return false;
  }
}

async function shareWithWebFile(src) {
  if (!navigator.share || !navigator.canShare || typeof File === 'undefined') return 'unavailable';
  try {
    var blob = await imageSourceToBlob(src);
    var file = new File([blob], 'clinical-visual.png', { type: blob.type || 'image/png' });
    if (!navigator.canShare({ files: [file] })) return 'unavailable';
    await navigator.share({ files: [file], title: 'Clinical visual', text: 'Clinical Assistant generated visual' });
    return 'shared';
  } catch (e) { return isShareCancel(e) ? 'cancelled' : 'unavailable'; }
}

async function downloadWithBrowser(src) {
  var blob = await imageSourceToBlob(src);
  var objectUrl = URL.createObjectURL(blob);
  var a = document.createElement('a');
  a.href = objectUrl;
  a.download = 'clinical-visual.png';
  a.rel = 'noopener';
  document.body.appendChild(a);
  a.click();
  a.remove();
  setTimeout(function() { URL.revokeObjectURL(objectUrl); }, 60000);

  if (isMobileBrowser() && typeof window.showToast === 'function') {
    window.showToast('If the download did not start, use Preview and long-press the image to save it.', 'info');
  }
}

function isMobileBrowser() {
  return !isNativeApp() && /Android|iPhone|iPad|iPod|Mobile/i.test(navigator.userAgent || '');
}

function isNativeApp() {
  return !!(window.Capacitor && (!window.Capacitor.isNativePlatform || window.Capacitor.isNativePlatform()));
}

function isShareCancel(error) {
  var message = String(error && (error.message || error.name) || '').toLowerCase();
  return /cancel|abort|dismiss|user denied|share canceled/.test(message);
}

async function imageSourceToBase64(src) {
  if (/^data:image\//i.test(src)) return src.split(',')[1] || '';
  var blob = await imageSourceToBlob(src);
  return new Promise(function(resolve, reject) {
    var reader = new FileReader();
    reader.onload = function() { resolve(String(reader.result || '').split(',')[1] || ''); };
    reader.onerror = function() { reject(reader.error || new Error('Could not read image')); };
    reader.readAsDataURL(blob);
  });
}

async function imageSourceToBlob(src) {
  if (/^data:image\//i.test(src)) {
    var parts = src.split(',');
    var meta = parts[0] || 'data:image/png;base64';
    var binary = atob(parts[1] || '');
    var bytes = new Uint8Array(binary.length);
    for (var i = 0; i < binary.length; i++) bytes[i] = binary.charCodeAt(i);
    return new Blob([bytes], { type: (meta.match(/data:([^;]+)/) || [])[1] || 'image/png' });
  }
  var response = await fetch(src, { credentials: 'omit' });
  if (!response.ok) throw new Error('Image download failed');
  return response.blob();
}

export function buildContextualImagePrompt(request, lastAnswer, lastSources) {
  var prompt = String(request || '').trim();
  if (!lastAnswer) return prompt;
  var sourceText = (lastSources || []).slice(0, 6).map(function (s, idx) {
    return '[' + (s.number || idx + 1) + '] ' + (s.title || s.resource || 'Source') + (s.page ? ', page ' + s.page : '');
  }).join('\n');
  return prompt + '\n\nUse this clinical answer as the required context. Do not switch topics or introduce unrelated scenes such as gardening. Create a medical teaching visual faithful to the answer.\n\nAnswer:\n' + String(lastAnswer || '').slice(0, 3000) + '\n\nSources:\n' + sourceText;
}

export function isImageRequest(text) {
  text = String(text || '').trim();
  var visualNoun = /\b(image|photo|picture|visual|illustration|diagram|figure|flowchart|infographic)\b/i;
  return /^(image|photo|picture|visual|illustration|diagram|figure|flowchart|infographic)$/i.test(text) ||
    (/\b(show|see|display|view)\b/i.test(text) && visualNoun.test(text) && text.split(/\s+/).length <= 8) ||
    /\b(generate|create|draw|make|render)\b[\s\S]{0,80}\b(image|picture|illustration|visual|infographic|diagram|flowchart)\b/i.test(text) ||
    /\b(generate|create|draw|make|render)\b[\s\S]{0,80}\b(an?|the)?\s*(algorithm|pathway|poster|teaching visual)\b/i.test(text);
}