// ============================================================
// CLINICAL ASSISTANT — evidence-grounded chat UI.
// Backend contract intentionally uses /api/clinical-assistant/* so the
// server can call native MCP directly without routing through mcpo.
// ============================================================
(function () {
  'use strict';

  var initialized = false;
  var messages = [];
  var lastAnswer = '';
  var lastSources = [];
  var mermaidReady = false;

  document.addEventListener('tabChanged', function (e) {
    if (e.detail && e.detail.tab === 'assistant') initIfNeeded();
  });

  function initIfNeeded() {
    if (initialized) return;
    var root = document.getElementById('assistant-tab');
    if (!root || !root.querySelector('#assistant-form')) return;
    initialized = true;
    bindEvents();
    loadStatus();
  }

  function bindEvents() {
    var form = document.getElementById('assistant-form');
    var clearBtn = document.getElementById('btn-assistant-clear');
    var copyBtn = document.getElementById('btn-assistant-copy');
    var imageBtn = document.getElementById('btn-assistant-image');
    var input = document.getElementById('assistant-input');

    if (form) form.addEventListener('submit', onAsk);
    if (clearBtn) clearBtn.addEventListener('click', clearConversation);
    if (copyBtn) copyBtn.addEventListener('click', copyLastAnswer);
    if (imageBtn) imageBtn.addEventListener('click', generateImage);
    if (input) input.addEventListener('keydown', function (e) {
      if ((e.ctrlKey || e.metaKey) && e.key === 'Enter') onAsk(e);
    });

    document.querySelectorAll('[data-assistant-example]').forEach(function (btn) {
      btn.addEventListener('click', function () {
        var el = document.getElementById('assistant-input');
        if (el) {
          el.value = btn.getAttribute('data-assistant-example') || '';
          el.focus();
        }
      });
    });
  }

  function loadStatus() {
    fetch('/api/clinical-assistant/status', { headers: getAuthHeaders(), credentials: 'same-origin' })
      .then(function (r) { return r.json(); })
      .then(function (data) {
        var label = document.getElementById('assistant-model-label');
        if (label && data.success) {
          label.textContent = data.chatModel ? ('Chat: ' + data.chatModel) : 'Admin model';
        }
      })
      .catch(function () {
        // Endpoint may not exist until backend slice lands; keep UI usable.
      });
  }

  function onAsk(e) {
    if (e) e.preventDefault();
    var input = document.getElementById('assistant-input');
    var includeContext = document.getElementById('assistant-include-context');
    var text = input ? input.value.trim() : '';
    if (!text) {
      if (typeof showToast === 'function') showToast('Enter a clinical question', 'error');
      return;
    }

    appendMessage('user', text);
    if (input) input.value = '';

    if (isImageRequest(text)) {
      generateImage(text, true);
      return;
    }

    setBusy(true, 'Searching indexed resources...');

    fetch('/api/clinical-assistant/chat', {
      method: 'POST',
      headers: getAuthHeaders(),
      credentials: 'same-origin',
      body: JSON.stringify({
        message: text,
        history: messages.slice(-8),
        includeContext: !includeContext || includeContext.checked
      })
    })
    .then(function (r) { return r.json().then(function (data) { data._status = r.status; return data; }); })
    .then(function (data) {
      setBusy(false, 'Ready');
      if (!data.success) throw new Error(data.error || ('Request failed (' + data._status + ')'));
      var answer = data.answer || data.markdown || '';
      lastAnswer = answer;
      lastSources = data.sources || data.citations || [];
      appendMessage('assistant', answer, lastSources, data.suggestions || []);
      renderSources(lastSources);
      if (data.model) {
        var label = document.getElementById('assistant-model-label');
        if (label) label.textContent = 'Chat: ' + data.model;
      }
    })
    .catch(function (err) {
      setBusy(false, 'Error', true);
      appendMessage('assistant', 'I could not complete the assistant request. ' + err.message + '\n\nIf this is the first run, the backend `/api/clinical-assistant/chat` route still needs to be wired to direct MCP search.');
      if (typeof showToast === 'function') showToast(err.message, 'error');
    });
  }

  function appendMessage(role, content, sources, suggestions, rawHtml) {
    var wrap = document.getElementById('assistant-messages');
    if (!wrap) return;
    var empty = wrap.querySelector('.assistant-empty');
    if (empty) empty.remove();

    messages.push({ role: role, content: content });
    var row = document.createElement('div');
    row.className = 'assistant-msg ' + role;
    var label = document.createElement('div');
    label.className = 'assistant-msg-label';
    label.textContent = role === 'user' ? 'You' : 'Assistant';
    var bubble = document.createElement('div');
    bubble.className = 'assistant-bubble';
    bubble.innerHTML = rawHtml ? sanitize(String(content || '')) : (role === 'assistant' ? renderMarkdown(content, sources || []) : escapeHtml(content));
    if (role === 'assistant' && suggestions && suggestions.length) {
      bubble.appendChild(renderSuggestionButtons(suggestions));
    }
    row.appendChild(label);
    row.appendChild(bubble);
    wrap.appendChild(row);
    renderEmbeddedBlocks(bubble);
    wrap.scrollTop = wrap.scrollHeight;
  }

  function renderSuggestionButtons(suggestions) {
    var wrap = document.createElement('div');
    wrap.className = 'assistant-suggestion-buttons';
    suggestions.forEach(function (s) {
      var btn = document.createElement('button');
      btn.type = 'button';
      btn.textContent = s;
      btn.addEventListener('click', function () {
        var input = document.getElementById('assistant-input');
        if (input) input.value = s;
        onAsk(new Event('submit'));
      });
      wrap.appendChild(btn);
    });
    return wrap;
  }

  function renderMarkdown(md, sources) {
    var text = String(md || '');
    var codeBlocks = [];
    text = text.replace(/```(\w+)?\n([\s\S]*?)```/g, function (_, lang, code) {
      var idx = codeBlocks.length;
      codeBlocks.push({ lang: (lang || '').toLowerCase(), code: code });
      return '\n@@CODEBLOCK_' + idx + '@@\n';
    });
    text = stripSourcesSection(text);
    text = renderLatexText(text);
    var html;
    if (window.marked && typeof window.marked.parse === 'function') {
      html = window.marked.parse(text, { breaks: true, gfm: true });
    } else {
      html = fallbackMarkdown(text);
    }
    html = html.replace(/\[(\d+)\]/g, function (_, n) {
      var source = sources[Number(n) - 1];
      if (!source) return '[' + n + ']';
      var title = source ? source.title || source.resource || 'Source' : 'Source';
      return '<a class="assistant-cite" href="#assistant-source-' + n + '" title="' + escapeHtml(title) + '">[' + n + ']</a>';
    });
    html = html.replace(/@@CODEBLOCK_(\d+)@@/g, function (_, idx) {
      var block = codeBlocks[Number(idx)] || { lang: '', code: '' };
      if (block.lang === 'mermaid') return '<div class="assistant-mermaid" data-mermaid="' + escapeAttr(block.code) + '">Rendering graph...</div>';
      if (block.lang === 'chart' || block.lang === 'chartjs') return '<canvas class="assistant-chart" data-chart="' + escapeAttr(block.code) + '"></canvas>';
      return '<pre><code>' + escapeHtml(block.code) + '</code></pre>';
    });
    return sanitize(html);
  }

  function fallbackMarkdown(text) {
    var html = escapeHtml(text)
      .replace(/^### (.*)$/gm, '<h3>$1</h3>')
      .replace(/^## (.*)$/gm, '<h2>$1</h2>')
      .replace(/^# (.*)$/gm, '<h1>$1</h1>')
      .replace(/\*\*(.*?)\*\*/g, '<strong>$1</strong>')
      .replace(/\*(.*?)\*/g, '<em>$1</em>')
      .replace(/`([^`]+)`/g, '<code>$1</code>');
    html = html.split(/\n{2,}/).map(function (block) {
      if (/^\s*<(h\d|ul|ol|pre|div)/.test(block)) return block;
      var lines = block.split('\n');
      if (lines.every(function (l) { return /^\s*[-*] /.test(l) || !l.trim(); })) {
        return '<ul>' + lines.filter(Boolean).map(function (l) { return '<li>' + l.replace(/^\s*[-*] /, '') + '</li>'; }).join('') + '</ul>';
      }
      if (lines.every(function (l) { return /^\s*\d+\. /.test(l) || !l.trim(); })) {
        return '<ol>' + lines.filter(Boolean).map(function (l) { return '<li>' + l.replace(/^\s*\d+\. /, '') + '</li>'; }).join('') + '</ol>';
      }
      return '<p>' + block.replace(/\n/g, '<br>') + '</p>';
    }).join('');
    return html;
  }

  function renderSources(sources) {
    var wrap = document.getElementById('assistant-sources');
    if (!wrap) return;
    if (!sources || sources.length === 0) {
      wrap.innerHTML = '<p class="assistant-muted">No citations returned.</p>';
      return;
    }
    wrap.innerHTML = sources.map(function (s, idx) {
      var n = idx + 1;
      var page = s.page || s.page_number || s.pageNumber;
      var meta = [];
      if (page) meta.push('page ' + page);
      if (s.doc_type || s.type) meta.push(s.doc_type || s.type);
      if (s.score != null) meta.push('score ' + Number(s.score).toFixed(3));
      return '<div class="assistant-source" id="assistant-source-' + n + '">' +
        '<strong>[' + n + '] ' + escapeHtml(s.title || s.resource || 'Untitled source') + '</strong>' +
        '<div class="assistant-source-meta">' + escapeHtml(meta.join(' · ') || 'indexed source') + '</div>' +
        (s.excerpt ? '<div class="assistant-source-excerpt">' + renderMarkdown(String(s.excerpt).slice(0, 900), []) + '</div>' : '') +
        '</div>';
    }).join('');
  }

  function renderEmbeddedBlocks(root) {
    root.querySelectorAll('[data-mermaid]').forEach(function (el) {
      ensureMermaid().then(function () {
        if (!window.mermaid) { el.textContent = el.getAttribute('data-mermaid'); return; }
        var id = 'assistant-mermaid-' + Math.random().toString(16).slice(2);
        window.mermaid.render(id, el.getAttribute('data-mermaid') || '')
          .then(function (out) { el.innerHTML = out.svg || ''; })
          .catch(function () { el.textContent = el.getAttribute('data-mermaid') || ''; });
      });
    });
    root.querySelectorAll('canvas[data-chart]').forEach(function (canvas) {
      if (!window.Chart) return;
      try {
        var cfg = JSON.parse(canvas.getAttribute('data-chart') || '{}');
        new window.Chart(canvas.getContext('2d'), cfg);
      } catch (e) {
        canvas.replaceWith(document.createTextNode('Invalid chart JSON'));
      }
    });
  }

  function ensureMermaid() {
    if (window.mermaid && mermaidReady) return Promise.resolve();
    return new Promise(function (resolve) {
      if (window.mermaid) { configureMermaid(); resolve(); return; }
      var script = document.createElement('script');
      script.src = '/vendor/mermaid.min.js';
      script.onload = function () { configureMermaid(); resolve(); };
      script.onerror = resolve;
      document.head.appendChild(script);
    });
  }

  function configureMermaid() {
    if (!window.mermaid) return;
    window.mermaid.initialize({ startOnLoad: false, securityLevel: 'strict', theme: 'default', flowchart: { useMaxWidth: true, htmlLabels: true } });
    mermaidReady = true;
  }

  function generateImage(promptOverride, fromChat) {
    var promptEl = document.getElementById('assistant-image-prompt');
    var out = document.getElementById('assistant-visual-output');
    var prompt = typeof promptOverride === 'string' ? promptOverride.trim() : (promptEl ? promptEl.value.trim() : '');
    if (!prompt && lastAnswer) prompt = 'Create a concise pediatric clinical teaching visual from this answer:\n\n' + lastAnswer.slice(0, 3000);
    if (!prompt) { if (typeof showToast === 'function') showToast('Enter an image prompt or ask a question first', 'error'); return; }
    if (fromChat) setBusy(true, 'Generating image...');
    if (out) out.innerHTML = '<p class="assistant-muted"><i class="fas fa-spinner fa-spin"></i> Generating image...</p>';
    fetch('/api/clinical-assistant/image', {
      method: 'POST', headers: getAuthHeaders(), credentials: 'same-origin',
      body: JSON.stringify({ prompt: prompt })
    })
    .then(function (r) { return r.json(); })
    .then(function (data) {
      if (!data.success) throw new Error(data.error || 'Image generation failed');
      var src = data.imageUrl || data.url || (data.base64 ? ('data:image/png;base64,' + data.base64) : '');
      if (!src) throw new Error('No image returned');
      if (out) out.innerHTML = '<img src="' + escapeAttr(src) + '" alt="Generated clinical visual"><a class="btn-sm btn-ghost" href="' + escapeAttr(src) + '" target="_blank" rel="noopener"><i class="fas fa-up-right-from-square"></i> Open</a>';
      if (fromChat) {
        setBusy(false, 'Ready');
        var html = '<div class="assistant-generated-image"><img src="' + escapeAttr(src) + '" alt="Generated clinical visual"><a class="btn-sm btn-ghost" href="' + escapeAttr(src) + '" target="_blank" rel="noopener"><i class="fas fa-up-right-from-square"></i> Open image</a></div>';
        appendMessage('assistant', html, [], [], true);
      }
    })
    .catch(function (err) {
      if (fromChat) setBusy(false, 'Error', true);
      if (out) out.innerHTML = '<p class="assistant-muted">' + escapeHtml(err.message) + '</p>';
      if (fromChat) appendMessage('assistant', 'Image generation failed: ' + err.message);
      if (typeof showToast === 'function') showToast(err.message, 'error');
    });
  }

  function clearConversation() {
    messages = [];
    lastAnswer = '';
    lastSources = [];
    var wrap = document.getElementById('assistant-messages');
    if (wrap) wrap.innerHTML = '<div class="assistant-empty"><i class="fas fa-book-medical"></i><h3>Evidence-first pediatric assistant</h3><p>Ask a focused clinical question over indexed resources.</p></div>';
    renderSources([]);
  }

  function copyLastAnswer() {
    if (!lastAnswer) { if (typeof showToast === 'function') showToast('No answer to copy', 'error'); return; }
    navigator.clipboard.writeText(lastAnswer).then(function () {
      if (typeof showToast === 'function') showToast('Copied answer', 'success');
    }).catch(function () {
      if (typeof showToast === 'function') showToast('Copy failed', 'error');
    });
  }

  function isImageRequest(text) {
    return /\b(generate|create|draw|make|show|render)\b[\s\S]{0,80}\b(image|picture|illustration|visual|infographic|diagram|flowchart)\b/i.test(text) ||
      /\b(image|picture|illustration|visual|infographic|diagram|flowchart)\b[\s\S]{0,80}\b(of|for|about|showing)\b/i.test(text);
  }

  function stripSourcesSection(text) {
    return String(text || '').replace(/\n\s*(---\s*)?(#{1,3}\s*)?(Sources|References)\s*\n[\s\S]*$/i, '').trim();
  }

  function renderLatexText(text) {
    if (!window.katex) return text;
    return String(text || '')
      .replace(/\$\$([\s\S]+?)\$\$/g, function(_, expr) { return safeKatex(expr, true); })
      .replace(/\\\[([\s\S]+?)\\\]/g, function(_, expr) { return safeKatex(expr, true); })
      .replace(/\$([^$\n]+?)\$/g, function(_, expr) { return safeKatex(expr, false); })
      .replace(/\\\((.+?)\\\)/g, function(_, expr) { return safeKatex(expr, false); });
  }

  function safeKatex(expr, displayMode) {
    try { return window.katex.renderToString(expr, { displayMode: displayMode, throwOnError: false }); }
    catch (e) { return escapeHtml(expr); }
  }

  function setBusy(isBusy, text, isError) {
    var status = document.getElementById('assistant-status');
    var label = document.getElementById('assistant-status-text');
    var send = document.getElementById('btn-assistant-send');
    if (status) {
      status.classList.toggle('busy', !!isBusy);
      status.classList.toggle('error', !!isError);
    }
    if (label) label.textContent = text || (isBusy ? 'Working...' : 'Ready');
    if (send) {
      send.disabled = !!isBusy;
      send.innerHTML = isBusy ? '<i class="fas fa-spinner fa-spin"></i> Searching' : '<i class="fas fa-paper-plane"></i> Ask';
    }
  }

  function escapeHtml(s) { return String(s == null ? '' : s).replace(/&/g, '&amp;').replace(/</g, '&lt;').replace(/>/g, '&gt;').replace(/"/g, '&quot;'); }
  function escapeAttr(s) { return escapeHtml(s).replace(/'/g, '&#39;'); }
  function sanitize(html) { return window.DOMPurify ? window.DOMPurify.sanitize(html, { ADD_ATTR: ['target'] }) : html; }
})();