// ObsiGate — AI Assistant sidebar.
//
// The panel adapts to three contexts:
//   • directory — a vault folder (opened from the tree context menu)
//   • documents — the file(s) currently open in tabs/panes
//   • general   — no document open: app help + file/directory creation actions
import { t } from './i18n.js';
import { buildAIPickerUI } from './ai.js';
import { safeCreateIcons } from './utils.js';
import { api, AuthManager } from './auth.js';
import { showToast } from './ui.js';

export const MODE = Object.freeze({
  DIRECTORY: 'directory',
  DOCUMENTS: 'documents',
  GENERAL: 'general',
});

/**
 * Gather the files currently open across the singleton TabManager and every
 * split-view pane (window globals avoid a circular import with ui.js).
 * The active tab of each pane is listed first.
 */
export function collectOpenDocuments() {
  const docs = [];
  const seen = new Set();
  const add = (vault, path) => {
    if (!vault || !path) return;
    const key = `${vault}\u0000${path}`;
    if (seen.has(key)) return;
    seen.add(key);
    docs.push({ vault, path });
  };
  const scan = (tm) => {
    if (!tm || !Array.isArray(tm._tabs)) return;
    const active = tm._tabs.find((x) => x.id === tm._activeTabId);
    if (active) add(active.vault, active.path);
    for (const tab of tm._tabs) add(tab.vault, tab.path);
  };
  try {
    scan(window.TabManager);
    const pm = window.PaneManager;
    if (pm && pm.tabManagers) Object.values(pm.tabManagers).forEach(scan);
  } catch { /* not ready yet */ }
  return docs;
}

export function documentsSignature(documents) {
  return (documents || []).map((d) => `${d.vault}/${d.path}`).join('\u0000');
}

class BooksLM {
  constructor() {
    this._isOpen = false;
    this._mode = MODE.GENERAL;
    this._vault = null;
    this._directory = null;
    this._documents = [];
    this._effectiveScope = MODE.GENERAL;
    this._messages = [];
    this._contextFiles = [];
    this._isLoading = false;
    this._abortCtrl = null;
    this._panel = null;
    this._isFullscreen = false;
  }

  // ── Public API ──────────────────────────────────────────────────────

  /**
   * Open the assistant for a specific context.
   * @param {object} opts
   * @param {'directory'|'documents'|'general'} opts.mode
   * @param {string|null} [opts.vault]
   * @param {string} [opts.directory]
   * @param {Array<{vault:string,path:string}>} [opts.documents]
   */
  async openContext(opts = {}) {
    const mode = opts.mode || MODE.GENERAL;
    const vault = opts.vault || null;
    const directory = opts.directory || '';
    const documents = Array.isArray(opts.documents) ? opts.documents : [];

    const sameContext =
      this._isOpen &&
      this._mode === mode &&
      this._vault === vault &&
      this._directory === directory &&
      documentsSignature(this._documents) === documentsSignature(documents);

    if (sameContext) {
      // Already open for this context: reveal a collapsed panel, else close.
      if (this._panel && this._panel.classList.contains('hidden')) {
        this._setHidden(false);
        document.dispatchEvent(new CustomEvent('bookslm:opened'));
      } else {
        this.close();
      }
      return;
    }

    this._mode = mode;
    this._vault = vault;
    this._directory = directory;
    this._documents = documents;
    this._effectiveScope = mode;
    this._messages = [];
    this._contextFiles = [];
    this._isLoading = true;
    this._loadHistory();

    if (!this._panel) {
      this._panel = this._render();
      document.body.appendChild(this._panel);
      if (typeof safeCreateIcons === 'function') safeCreateIcons();
    }

    // An explicit open always reveals the panel, even if it was collapsed
    // in a previous session (previously it stayed hidden → "ne s'ouvre plus").
    this._setHidden(false);
    this._updateHeader();
    this._updateStatus();
    this._renderMessages();
    this._showSuggestions();

    requestAnimationFrame(() => {
      this._panel.classList.add('open');
      document.dispatchEvent(new CustomEvent('bookslm:opened', {
        detail: { mode, vault, directory, documents },
      }));
    });
    this._isOpen = true;

    await this._loadContext();
    this._isLoading = false;
  }

  /** Backwards-compatible helper: open the assistant on a directory. */
  async open(vault, directory) {
    return this.openContext({ mode: MODE.DIRECTORY, vault, directory });
  }

  /**
   * Open the assistant using the current application context: the open
   * document(s) if any, otherwise the General assistant.
   */
  async openForCurrentContext() {
    const docs = collectOpenDocuments();
    if (docs.length) {
      const vault = docs[0].vault;
      const scoped = docs.filter((d) => d.vault === vault);
      return this.openContext({ mode: MODE.DOCUMENTS, vault, documents: scoped });
    }
    return this.openContext({ mode: MODE.GENERAL });
  }

  close() {
    if (!this._panel || !this._isOpen) return;
    this._panel.classList.remove('open');
    this._isOpen = false;
    document.dispatchEvent(new CustomEvent('bookslm:closed'));
    if (this._abortCtrl) {
      this._abortCtrl.abort();
      this._abortCtrl = null;
    }
  }

  _setHidden(hidden) {
    if (!this._panel) return;
    this._panel.classList.toggle('hidden', hidden);
    try {
      localStorage.setItem('obsigate-bookslm-hidden', hidden ? 'true' : 'false');
    } catch { /* */ }
    this._updateToggleIcon();
  }

  /** Collapse/expand while keeping the panel mounted (header toggle button). */
  _toggleSidebar() {
    if (!this._panel) return;
    const isHidden = !this._panel.classList.contains('hidden');
    this._setHidden(isHidden);
    document.dispatchEvent(new CustomEvent(isHidden ? 'bookslm:closed' : 'bookslm:opened'));
  }

  _updateToggleIcon() {
    if (!this._panel) return;
    const btn = this._panel.querySelector('.bookslm-btn-toggle');
    if (!btn) return;
    const isHidden = this._panel.classList.contains('hidden');
    const icon = btn.querySelector('i[data-lucide]');
    if (!icon) return;
    icon.setAttribute('data-lucide', isHidden ? 'panel-right-open' : 'panel-right-close');
    if (typeof safeCreateIcons === 'function') safeCreateIcons();
  }

  newConversation() {
    this._messages = [];
    this._saveHistory();
    if (this._panel) {
      this._renderMessages();
      this._showSuggestions();
    }
  }

  exportConversation() {
    if (!this._messages.length) return;
    const label = this._contextTitle() || 'assistant';
    let md = `# ${label}\n\n`;
    for (const msg of this._messages) {
      const role = msg.role === 'user' ? '**You**' : '**AI**';
      md += `### ${role}\n\n${msg.content}\n\n---\n\n`;
    }
    const blob = new Blob([md], { type: 'text/markdown' });
    const a = document.createElement('a');
    a.href = URL.createObjectURL(blob);
    a.download = `obsigate-assistant-${label.replace(/[^\w.-]+/g, '_')}.md`;
    a.click();
    URL.revokeObjectURL(a.href);
  }

  openFile(path) {
    window.dispatchEvent(new CustomEvent('obsigate:open-file', {
      detail: { vault: this._vault, path },
    }));
  }

  // ── Context ─────────────────────────────────────────────────────────

  async _loadContext() {
    if (this._mode === MODE.GENERAL) {
      this._effectiveScope = MODE.GENERAL;
      this._contextFiles = [];
      this._updateStatus({ files: [], total_chars: 0, file_count: 0, scope: MODE.GENERAL, max_total_chars: 200000 });
      this._showSuggestions();
      return;
    }

    const payload = {
      mode: this._mode,
      vault: this._vault,
      directory: this._directory,
      context_files: this._mode === MODE.DOCUMENTS ? this._documents.map((d) => d.path) : [],
    };
    try {
      const data = await api('/api/ai/bookslm/context', {
        method: 'POST',
        headers: { 'Content-Type': 'application/json' },
        body: JSON.stringify(payload),
      });
      this._contextFiles = data.files || [];
      this._effectiveScope = data.scope || this._mode;
      this._updateStatus(data);
      this._showSuggestions();
    } catch (e) {
      console.warn('AI assistant: context load failed', e);
      this._contextFiles = [];
      this._updateStatus({ error: e.message });
    }
  }

  _contextMeta() {
    if (this._mode === MODE.DOCUMENTS) {
      const names = this._documents.map((d) => (d.path || '').split('/').pop()).filter(Boolean);
      return {
        icon: 'file-text',
        title: t('ai.context_documents', { count: this._documents.length }),
        subtitle: names.slice(0, 3).join(', ') + (names.length > 3 ? '…' : ''),
      };
    }
    if (this._mode === MODE.DIRECTORY) {
      const name = this._directory ? this._directory.split('/').filter(Boolean).pop() : this._vault;
      return {
        icon: 'folder',
        title: name || this._vault || t('bookslm.title'),
        subtitle: `${this._vault}${this._directory ? '/' + this._directory : ''}`,
      };
    }
    return {
      icon: 'sparkles',
      title: t('ai.context_general'),
      subtitle: t('ai.context_general_desc'),
    };
  }

  _contextTitle() {
    return this._contextMeta().title;
  }

  // ── Rendering ───────────────────────────────────────────────────────

  _render() {
    const panel = document.createElement('div');
    panel.className = 'bookslm-panel';
    panel.innerHTML = `
      <div class="bookslm-header">
        <button class="bookslm-btn-toggle" title="${t('bookslm.toggle_sidebar')}" aria-label="${t('bookslm.toggle_sidebar')}">
          <i data-lucide="panel-right-close" style="width:16px;height:16px"></i>
        </button>
        <span class="bookslm-context-icon"><i data-lucide="sparkles" style="width:16px;height:16px"></i></span>
        <div class="bookslm-header-titles">
          <span class="bookslm-title"></span>
          <span class="bookslm-subtitle"></span>
        </div>
        <div class="bookslm-header-actions">
          <button class="bookslm-btn-new" title="${t('bookslm.new_conversation')}" aria-label="${t('bookslm.new_conversation')}"><i data-lucide="plus" style="width:16px;height:16px"></i></button>
          <button class="bookslm-btn-export" title="${t('bookslm.export')}" aria-label="${t('bookslm.export')}"><i data-lucide="download" style="width:16px;height:16px"></i></button>
          <button class="bookslm-btn-fullscreen" title="${t('ai.fullscreen')}" aria-label="${t('ai.fullscreen')}"><i data-lucide="maximize-2" style="width:16px;height:16px"></i></button>
          <button class="bookslm-btn-close" title="${t('ai.close')}" aria-label="${t('ai.close')}"><i data-lucide="x" style="width:16px;height:16px"></i></button>
        </div>
      </div>
      <div class="bookslm-toolbar">
        <span class="bookslm-toolbar-label">${t('ai.model_settings')}</span>
        <span class="bookslm-picker-host"></span>
      </div>
      <div class="bookslm-status"></div>
      <div class="bookslm-suggestions"></div>
      <div class="bookslm-messages"></div>
      <div class="bookslm-input-area">
        <textarea placeholder="${t('bookslm.placeholder')}" rows="1" aria-label="${t('bookslm.placeholder')}"></textarea>
        <button class="bookslm-btn-send" title="${t('bookslm.send')}">${t('bookslm.send')}</button>
      </div>
      <div class="bookslm-input-hint">${t('ai.input_hint')}</div>
    `;

    // Provider/model picker lives on its own toolbar row so the header
    // actions stay visible regardless of the provider/model text width.
    const pickerHost = panel.querySelector('.bookslm-picker-host');
    buildAIPickerUI().then((picker) => {
      if (!picker || !pickerHost) return;
      pickerHost.replaceWith(picker);
      if (typeof safeCreateIcons === 'function') safeCreateIcons();
    }).catch(() => { /* ignore */ });

    panel.querySelector('.bookslm-btn-close').addEventListener('click', () => this.close());
    panel.querySelector('.bookslm-btn-new').addEventListener('click', () => this.newConversation());
    panel.querySelector('.bookslm-btn-export').addEventListener('click', () => this.exportConversation());
    panel.querySelector('.bookslm-btn-toggle').addEventListener('click', () => this._toggleSidebar());
    panel.querySelector('.bookslm-btn-fullscreen').addEventListener('click', () => {
      this._isFullscreen = !this._isFullscreen;
      panel.classList.toggle('fullscreen', this._isFullscreen);
      const icon = panel.querySelector('.bookslm-btn-fullscreen i');
      if (icon) {
        icon.setAttribute('data-lucide', this._isFullscreen ? 'minimize-2' : 'maximize-2');
        if (typeof safeCreateIcons === 'function') safeCreateIcons();
      }
    });

    panel.querySelector('.bookslm-btn-send').addEventListener('click', () => this._sendMessage());

    const textarea = panel.querySelector('textarea');
    textarea.addEventListener('input', () => {
      textarea.style.height = 'auto';
      textarea.style.height = Math.min(textarea.scrollHeight, 140) + 'px';
    });
    textarea.addEventListener('keydown', (e) => {
      if (e.key !== 'Enter') return;
      if (e.ctrlKey || e.metaKey) {
        // Ctrl/Cmd+Enter → insert a newline at the caret.
        e.preventDefault();
        const start = textarea.selectionStart;
        const end = textarea.selectionEnd;
        textarea.value = textarea.value.slice(0, start) + '\n' + textarea.value.slice(end);
        textarea.selectionStart = textarea.selectionEnd = start + 1;
        textarea.dispatchEvent(new Event('input'));
        return;
      }
      // Enter (with or without Shift) → submit. Shift+Enter also submits so
      // the documented shortcut (Ctrl+Enter) is the only way to add a line.
      e.preventDefault();
      this._sendMessage();
    });

    return panel;
  }

  _updateHeader() {
    if (!this._panel) return;
    const meta = this._contextMeta();
    const title = this._panel.querySelector('.bookslm-title');
    const subtitle = this._panel.querySelector('.bookslm-subtitle');
    const icon = this._panel.querySelector('.bookslm-context-icon i');
    if (title) title.textContent = meta.title;
    if (subtitle) subtitle.textContent = meta.subtitle || '';
    if (icon) icon.setAttribute('data-lucide', meta.icon);
    if (typeof safeCreateIcons === 'function') safeCreateIcons();
  }

  _updateStatus(data) {
    if (!this._panel) return;
    const status = this._panel.querySelector('.bookslm-status');
    if (!status) return;

    if (data && data.error) {
      status.innerHTML = `<span class="bookslm-status-error">⚠ ${t('bookslm.no_context')}</span>`;
      return;
    }
    if (data && Array.isArray(data.files)) {
      const count = data.files.length;
      const chars = data.total_chars || 0;
      const maxChars = data.max_total_chars || 200000;
      const pct = Math.min(100, Math.round((chars / maxChars) * 100));
      const label = data.scope === MODE.GENERAL
        ? t('ai.context_general_desc')
        : `${t('bookslm.files_indexed', { count })}, ${t('bookslm.chars_loaded', { chars: Math.round(chars / 1000) + 'K' })}`;
      status.innerHTML = `
        <span class="bookslm-status-text">${label}</span>
        <div class="bookslm-context-bar" role="progressbar" aria-valuenow="${pct}" aria-valuemin="0" aria-valuemax="100"><div class="bookslm-context-fill" style="width:${pct}%"></div></div>
      `;
    } else if (this._isLoading) {
      status.textContent = '⏳ …';
    }
  }

  _suggestionsForContext() {
    if (this._mode === MODE.GENERAL) {
      return [
        t('ai.suggestion_capabilities'),
        t('ai.suggestion_search'),
        t('ai.suggestion_create_file'),
      ];
    }
    if (this._mode === MODE.DOCUMENTS) {
      return [
        t('ai.suggestion_docs_summary'),
        t('ai.suggestion_docs_keypoints'),
        t('ai.suggestion_docs_contradictions'),
      ];
    }
    return [
      t('bookslm.suggestion_summary'),
      t('bookslm.suggestion_themes'),
      t('bookslm.suggestion_contradictions'),
    ];
  }

  _showSuggestions() {
    if (!this._panel) return;
    const sugEl = this._panel.querySelector('.bookslm-suggestions');
    if (!sugEl) return;
    sugEl.innerHTML = '';
    if (this._messages.length) return;

    for (const s of this._suggestionsForContext()) {
      const btn = document.createElement('button');
      btn.className = 'bookslm-suggestion';
      btn.textContent = s;
      btn.addEventListener('click', () => {
        const textarea = this._panel.querySelector('textarea');
        if (textarea) {
          textarea.value = s;
          this._sendMessage();
        }
      });
      sugEl.appendChild(btn);
    }
  }

  _renderMessages() {
    if (!this._panel) return;
    const container = this._panel.querySelector('.bookslm-messages');
    if (!container) return;
    container.innerHTML = '';

    for (const msg of this._messages) {
      const bubble = document.createElement('div');
      bubble.className = `bookslm-bubble ${msg.role}`;

      if (msg.role === 'assistant') {
        const { text, actions } = this._extractActions(msg.content || '');
        bubble.innerHTML = this._renderMarkdown(text);
        if (actions.length) {
          const actionsDiv = document.createElement('div');
          actionsDiv.className = 'bookslm-actions';
          actions.forEach((action) => actionsDiv.appendChild(this._renderActionCard(action)));
          bubble.appendChild(actionsDiv);
        }
        if (msg.sources && msg.sources.length) {
          const sourcesDiv = document.createElement('div');
          sourcesDiv.className = 'bookslm-sources';
          for (const src of msg.sources) {
            const badge = document.createElement('span');
            badge.className = 'bookslm-source-badge';
            badge.textContent = `📄 ${src.split('/').pop()}`;
            badge.title = src;
            badge.addEventListener('click', () => this.openFile(src));
            sourcesDiv.appendChild(badge);
          }
          bubble.appendChild(sourcesDiv);
        }
      } else {
        bubble.textContent = msg.content;
      }

      container.appendChild(bubble);
    }

    container.scrollTop = container.scrollHeight;
  }

  // ── Actions (general assistant) ─────────────────────────────────────

  _extractActions(text) {
    const actions = [];
    const re = /```obsigate-action\s*\n([\s\S]*?)```/g;
    let match;
    while ((match = re.exec(text)) !== null) {
      try {
        const obj = JSON.parse(match[1].trim());
        if (obj && typeof obj.action === 'string') actions.push(obj);
      } catch { /* malformed block — ignore */ }
    }
    return { text: text.replace(re, '').trim(), actions };
  }

  _renderActionCard(action) {
    const card = document.createElement('div');
    card.className = 'bookslm-action';
    const isDir = action.action === 'create_directory';
    const label = isDir
      ? t('ai.action_create_dir', { path: action.path || '' })
      : t('ai.action_create_file', { path: action.path || '' });
    const meta = document.createElement('div');
    meta.className = 'bookslm-action-meta';
    meta.innerHTML = `<span class="bookslm-action-icon">${isDir ? '📁' : '📄'}</span>`;
    const textEl = document.createElement('span');
    textEl.textContent = label;
    meta.appendChild(textEl);
    card.appendChild(meta);

    const apply = document.createElement('button');
    apply.className = 'bookslm-action-apply';
    apply.textContent = t('ai.action_apply');
    apply.addEventListener('click', async () => {
      apply.disabled = true;
      apply.textContent = t('ai.action_applying');
      try {
        await this._applyAction(action);
        card.classList.add('done');
        apply.textContent = t('ai.action_applied');
      } catch (e) {
        apply.disabled = false;
        apply.textContent = t('ai.action_apply');
        showToast(t('ai.action_failed', { error: e.message }), 'error');
      }
    });
    card.appendChild(apply);
    return card;
  }

  async _applyAction(action) {
    if (!action.vault || !action.path) throw new Error('missing vault/path');
    if (action.action === 'create_file') {
      await api(`/api/file/${encodeURIComponent(action.vault)}`, {
        method: 'POST',
        headers: { 'Content-Type': 'application/json' },
        body: JSON.stringify({ path: action.path, content: action.content || '' }),
      });
      showToast(t('ai.action_created_file', { path: action.path }), 'success');
    } else if (action.action === 'create_directory') {
      await api(`/api/directory/${encodeURIComponent(action.vault)}`, {
        method: 'POST',
        headers: { 'Content-Type': 'application/json' },
        body: JSON.stringify({ path: action.path }),
      });
      showToast(t('ai.action_created_dir', { path: action.path }), 'success');
    } else {
      throw new Error(`unknown action: ${action.action}`);
    }
    try {
      const m = await import('./sidebar.js');
      if (m && typeof m.refreshSidebarTreePreservingState === 'function') {
        await m.refreshSidebarTreePreservingState();
      }
    } catch { /* tree refresh is best-effort */ }
  }

  // ── Messaging ───────────────────────────────────────────────────────

  async _sendMessage() {
    const textarea = this._panel.querySelector('textarea');
    const text = (textarea.value || '').trim();
    if (!text || this._isLoading) return;

    textarea.value = '';
    textarea.style.height = 'auto';

    const sugEl = this._panel.querySelector('.bookslm-suggestions');
    if (sugEl) sugEl.innerHTML = '';

    // Snapshot prior turns BEFORE appending the new user message.
    const history = this._messages
      .filter((m) => m.content && m.content.trim())
      .map((m) => ({ role: m.role, content: m.content }));

    this._messages.push({ role: 'user', content: text });
    this._renderMessages();

    const assistantMsg = { role: 'assistant', content: '', sources: [] };
    this._messages.push(assistantMsg);
    this._renderMessages();
    this._isLoading = true;

    const sendBtn = this._panel.querySelector('.bookslm-btn-send');
    if (sendBtn) sendBtn.disabled = true;

    this._abortCtrl = new AbortController();

    try {
      let provider = null;
      let model = null;
      try {
        const picker = JSON.parse(localStorage.getItem('obsigate_ai_picker') || '{}');
        provider = picker.provider || null;
        model = picker.model || null;
      } catch { /* */ }

      const payload = {
        mode: this._mode,
        vault: this._vault,
        directory: this._directory,
        context_files: this._mode === MODE.DOCUMENTS ? this._documents.map((d) => d.path) : [],
        message: text,
        conversation_history: history,
        provider,
        model,
      };

      const doFetch = () => {
        const headers = { 'Content-Type': 'application/json', ...(AuthManager.getAuthHeaders() || {}) };
        return fetch('/api/ai/bookslm/chat', {
          method: 'POST',
          headers,
          credentials: 'include',
          body: JSON.stringify(payload),
          signal: this._abortCtrl.signal,
        });
      };
      let resp = await doFetch();
      if (resp.status === 401 && AuthManager._authEnabled) {
        await AuthManager.refreshAccessToken();
        resp = await doFetch();
      }
      if (!resp.ok) {
        let detail = `HTTP ${resp.status}`;
        try { detail = (await resp.json()).detail || detail; } catch { /* */ }
        throw new Error(detail);
      }

      const reader = resp.body.getReader();
      const decoder = new TextDecoder();
      let buffer = '';
      let currentEvent = 'message';

      const handleLine = (line) => {
        if (line.startsWith('event:')) {
          currentEvent = line.slice(6).trim();
          return;
        }
        if (!line.startsWith('data:')) return;
        const raw = line.slice(5).trim();
        if (!raw || raw === '[DONE]') return;
        let data;
        try {
          data = JSON.parse(raw);
        } catch {
          assistantMsg.content += raw;
          return;
        }
        if (currentEvent === 'error' || data.error) {
          const msg = data.error || t('bookslm.error');
          assistantMsg.content += (assistantMsg.content ? '\n\n' : '') + '⚠ ' + msg;
          return;
        }
        const chunk = data.token || data.content || '';
        if (chunk) assistantMsg.content += chunk;
        if (data.sources) assistantMsg.sources = data.sources;
      };

      while (true) {
        const { done, value } = await reader.read();
        if (done) break;
        buffer += decoder.decode(value, { stream: true });
        const lines = buffer.split('\n');
        buffer = lines.pop() || '';
        for (const line of lines) handleLine(line);
        this._renderMessages();
      }
      if (buffer) handleLine(buffer);

      if (!assistantMsg.sources.length && this._contextFiles.length) {
        const contentLower = assistantMsg.content.toLowerCase();
        assistantMsg.sources = this._contextFiles
          .filter((f) => {
            const name = (f.path || f || '').split('/').pop().toLowerCase();
            return name && contentLower.includes(name);
          })
          .map((f) => f.path || f);
      }
    } catch (e) {
      if (e.name !== 'AbortError') {
        assistantMsg.content = `⚠ Error: ${e.message}`;
        console.warn('AI assistant chat error:', e);
      }
    }

    this._isLoading = false;
    if (sendBtn) sendBtn.disabled = false;
    this._abortCtrl = null;
    this._renderMessages();
    this._saveHistory();
  }

  // ── Markdown (lightweight) ──────────────────────────────────────────

  _renderMarkdown(text) {
    if (!text) return '';
    // Escape HTML first so model output cannot inject markup.
    let html = text
      .replace(/&/g, '&amp;')
      .replace(/</g, '&lt;')
      .replace(/>/g, '&gt;')
      .replace(/```(\w*)\n([\s\S]*?)```/g, '<pre><code>$2</code></pre>')
      .replace(/`([^`]+)`/g, '<code>$1</code>')
      .replace(/\*\*(.+?)\*\*/g, '<strong>$1</strong>')
      .replace(/\*(.+?)\*/g, '<em>$1</em>')
      .replace(/\[([^\]]+)\]\(([^)]+)\)/g, '<a href="$2" target="_blank" rel="noopener">$1</a>')
      .replace(/^[*\-+] (.+)$/gm, '<li>$1</li>')
      .replace(/^### (.+)$/gm, '<h4>$1</h4>')
      .replace(/^## (.+)$/gm, '<h3>$1</h3>')
      .replace(/\n\n/g, '</p><p>')
      .replace(/\n/g, '<br>');
    return `<p>${html}</p>`;
  }

  // ── History persistence ─────────────────────────────────────────────

  _historyKey() {
    const ctx = this._mode === MODE.DOCUMENTS
      ? documentsSignature(this._documents)
      : (this._directory || this._vault || 'general');
    return `bookslm-history-${this._mode}-${ctx.replace(/[^\w.-]+/g, '_')}`;
  }

  _saveHistory() {
    try {
      localStorage.setItem(this._historyKey(), JSON.stringify(this._messages));
    } catch { /* */ }
  }

  _loadHistory() {
    try {
      const data = localStorage.getItem(this._historyKey());
      this._messages = data ? JSON.parse(data) : [];
    } catch {
      this._messages = [];
    }
  }
}

const booksLM = new BooksLM();
export default booksLM;
export { BooksLM };