/**
 * TASKMATE - Assistant Manager
 * ============================
 * Claude Assistant Chat Interface
 */

import api from './api.js';
import syncManager from './sync.js';
import { $ } from './utils.js';

class AssistantManager {
  constructor() {
    this.sessions = [];
    this.currentSessionId = null;
    this.sessionStatus = null; // running, ended, stopped, error
    this.streamingMessageEl = null;
    this.streamingContent = '';
    this.initialized = false;
  }

  async init() {
    if (this.initialized) return;

    // DOM Elements
    this.sessionsListEl = $('#assistant-sessions-list');
    this.messagesEl = $('#assistant-messages');
    this.inputEl = $('#assistant-input');
    this.sendBtn = $('#btn-send-message');
    this.newSessionBtn = $('#btn-new-session');
    this.chatTitleEl = $('#assistant-chat-title');
    this.statusBadgeEl = $('#assistant-status-badge');
    this.chatEl = document.querySelector('.assistant-chat');
    this.emptyEl = $('#assistant-empty');

    this.bindEvents();
    this.setupSocketListeners();
    this.updateChatState();

    this.initialized = true;
    console.log('[Assistant] Initialized');
  }

  bindEvents() {
    // New session
    this.newSessionBtn?.addEventListener('click', () => this.startSession());

    // Send message
    this.sendBtn?.addEventListener('click', () => this.sendMessage());

    // Textarea: Enter sends, Shift+Enter new line, auto-resize
    this.inputEl?.addEventListener('keydown', (e) => {
      if (e.key === 'Enter' && !e.shiftKey) {
        e.preventDefault();
        this.sendMessage();
      }
    });

    this.inputEl?.addEventListener('input', () => {
      this.autoResizeInput();
    });
  }

  setupSocketListeners() {
    const socket = syncManager.socket;
    if (!socket) {
      // Socket not yet connected, wait for it
      const checkSocket = setInterval(() => {
        if (syncManager.socket) {
          clearInterval(checkSocket);
          this._attachSocketEvents(syncManager.socket);
        }
      }, 500);
      return;
    }
    this._attachSocketEvents(socket);
  }

  _attachSocketEvents(socket) {
    // Streaming output
    socket.on('assistant:output', (data) => {
      if (data.sessionId !== this.currentSessionId) return;
      this.handleOutput(data.content);
    });

    // Status changes
    socket.on('assistant:status', (data) => {
      if (data.sessionId && data.sessionId !== this.currentSessionId) return;

      if (data.status === 'error') {
        this.setStatus('error');
        this.showToast(data.error || 'Fehler beim Assistenten', 'error');
        return;
      }

      this.setStatus(data.status);

      // Finalize streaming when message processing completes
      if (data.status === 'ended' || data.status === 'stopped' || data.status === 'active') {
        this.finalizeStreaming();
        if (data.status !== 'active') {
          this.loadSessions();
        }
      }
    });
  }

  // =====================
  // SHOW / HIDE
  // =====================

  async show() {
    await this.loadSessions();
  }

  hide() {
    // Nothing to clean up
  }

  // =====================
  // SESSIONS
  // =====================

  async loadSessions() {
    try {
      this.sessions = await api.getAssistantSessions();
      this.renderSessionsList();
    } catch (err) {
      console.error('[Assistant] Fehler beim Laden der Sessions:', err);
    }
  }

  renderSessionsList() {
    if (!this.sessionsListEl) return;

    if (this.sessions.length === 0) {
      this.sessionsListEl.innerHTML = '<div style="padding: 16px; text-align: center; color: var(--text-muted); font-size: var(--text-sm);">Keine Sessions vorhanden</div>';
      return;
    }

    this.sessionsListEl.innerHTML = this.sessions.map(s => {
      const isActive = s.id === this.currentSessionId;
      const date = new Date(s.created_at);
      const dateStr = `${String(date.getDate()).padStart(2, '0')}.${String(date.getMonth() + 1).padStart(2, '0')}.${date.getFullYear()}`;
      const statusLabel = s.status === 'active' ? 'Aktiv' : 'Beendet';

      return `
        <div class="assistant-session-item ${isActive ? 'active' : ''}" data-session-id="${s.id}">
          <div class="assistant-session-info">
            <div class="assistant-session-title">${this.escapeHtml(s.title)}</div>
            <div class="assistant-session-meta">${dateStr} - ${statusLabel}</div>
          </div>
          <button class="assistant-session-delete" data-delete-id="${s.id}" title="Session loeschen">
            <svg viewBox="0 0 24 24" width="14" height="14" fill="none" stroke="currentColor" stroke-width="2"><path d="M18 6L6 18M6 6l12 12"/></svg>
          </button>
        </div>
      `;
    }).join('');

    // Click handlers
    this.sessionsListEl.querySelectorAll('.assistant-session-item').forEach(el => {
      el.addEventListener('click', (e) => {
        if (e.target.closest('.assistant-session-delete')) return;
        const id = parseInt(el.dataset.sessionId, 10);
        this.selectSession(id);
      });
    });

    this.sessionsListEl.querySelectorAll('.assistant-session-delete').forEach(btn => {
      btn.addEventListener('click', (e) => {
        e.stopPropagation();
        const id = parseInt(btn.dataset.deleteId, 10);
        this.deleteSession(id);
      });
    });
  }

  async selectSession(id) {
    this.currentSessionId = id;
    const session = this.sessions.find(s => s.id === id);

    if (session) {
      this.chatTitleEl.textContent = session.title;

      if (session.status === 'active') {
        // Aktive Session mit Backend verbinden
        const socket = syncManager.socket;
        if (socket) {
          socket.emit('assistant:start', { sessionId: id });
        }
      } else {
        this.setStatus(session.status);
      }
    }

    this.renderSessionsList();
    this.updateChatState();
    await this.loadMessages(id);
  }

  async loadMessages(sessionId) {
    if (!this.messagesEl) return;
    this.messagesEl.innerHTML = '';

    try {
      const messages = await api.getAssistantMessages(sessionId);
      messages.forEach(msg => {
        this.renderMessage(msg.role, msg.content);
      });
      this.scrollToBottom();
    } catch (err) {
      console.error('[Assistant] Fehler beim Laden der Nachrichten:', err);
    }
  }

  async startSession(taskContext = null) {
    try {
      const session = await api.createAssistantSession({
        title: 'Neue Session',
        taskContext
      });

      this.currentSessionId = session.id;
      this.chatTitleEl.textContent = session.title;
      this.messagesEl.innerHTML = '';
      this.setStatus('active');
      this.updateChatState();

      // Start Claude process via Socket
      const socket = syncManager.socket;
      if (socket) {
        socket.emit('assistant:start', { sessionId: session.id });
      }

      await this.loadSessions();
      this.showToast('Session gestartet', 'success');
    } catch (err) {
      console.error('[Assistant] Fehler beim Starten:', err);
      this.showToast('Fehler beim Starten der Session', 'error');
    }
  }

  async deleteSession(id) {
    if (!confirm('Session wirklich loeschen?')) return;

    try {
      await api.deleteAssistantSession(id);

      if (this.currentSessionId === id) {
        this.currentSessionId = null;
        this.messagesEl.innerHTML = '';
        this.chatTitleEl.textContent = 'Assistent';
        this.setStatus(null);
        this.updateChatState();
      }

      await this.loadSessions();
      this.showToast('Session geloescht', 'success');
    } catch (err) {
      console.error('[Assistant] Fehler beim Loeschen:', err);
      this.showToast('Fehler beim Loeschen', 'error');
    }
  }

  async endSession() {
    const socket = syncManager.socket;
    if (socket) {
      socket.emit('assistant:stop');
    }
  }

  // =====================
  // MESSAGING
  // =====================

  async sendMessage() {
    const text = this.inputEl?.value?.trim();
    if (!text || !this.currentSessionId) return;

    // Beendete/gestoppte Session zuerst reaktivieren
    if (this.sessionStatus === 'ended' || this.sessionStatus === 'stopped') {
      try {
        await this._reactivateSession();
        this.loadSessions();
      } catch (err) {
        console.error('[Assistant] Reaktivierung fehlgeschlagen:', err);
        this.showToast('Session konnte nicht reaktiviert werden', 'error');
        return;
      }
    }

    // Render user message
    this.renderMessage('user', text);
    this.inputEl.value = '';
    this.autoResizeInput();
    this.scrollToBottom();

    // Send via socket
    const socket = syncManager.socket;
    if (socket) {
      socket.emit('assistant:message', { message: text });
    }

    // Prepare streaming bubble
    this.streamingContent = '';
    this.streamingMessageEl = this.createMessageEl('assistant', '');
    this.streamingMessageEl.classList.add('streaming');
    this.messagesEl.appendChild(this.streamingMessageEl);
    this.setStatus('thinking');
  }

  _reactivateSession() {
    return new Promise((resolve, reject) => {
      const socket = syncManager.socket;
      if (!socket) return reject(new Error('Kein Socket'));

      const onStatus = (data) => {
        if (data.sessionId !== this.currentSessionId) return;
        socket.off('assistant:status', onStatus);
        clearTimeout(timeout);
        if (data.status === 'error') {
          reject(new Error(data.error || 'Fehler'));
        } else {
          resolve();
        }
      };

      const timeout = setTimeout(() => {
        socket.off('assistant:status', onStatus);
        reject(new Error('Timeout'));
      }, 10000);

      socket.on('assistant:status', onStatus);
      socket.emit('assistant:start', { sessionId: this.currentSessionId });
    });
  }

  handleOutput(content) {
    if (!this.streamingMessageEl) {
      // Create streaming bubble if not exists
      this.streamingContent = '';
      this.streamingMessageEl = this.createMessageEl('assistant', '');
      this.streamingMessageEl.classList.add('streaming');
      this.messagesEl.appendChild(this.streamingMessageEl);
    }

    this.streamingContent += content;
    this.streamingMessageEl.innerHTML = this.renderMarkdown(this.streamingContent);
    this.setStatus('running');
    this.scrollToBottom();
  }

  finalizeStreaming() {
    if (this.streamingMessageEl) {
      this.streamingMessageEl.classList.remove('streaming');
      this.streamingMessageEl = null;
      this.streamingContent = '';
    }
  }

  // =====================
  // RENDERING
  // =====================

  renderMessage(role, content) {
    const el = this.createMessageEl(role, content);
    this.messagesEl.appendChild(el);
  }

  createMessageEl(role, content) {
    const el = document.createElement('div');
    el.className = `assistant-message ${role}`;

    if (role === 'assistant') {
      el.innerHTML = this.renderMarkdown(content);
    } else {
      el.textContent = content;
    }

    return el;
  }

  renderMarkdown(text) {
    if (!text) return '';

    let html = this.escapeHtml(text);

    // Code blocks
    html = html.replace(/```(\w*)\n?([\s\S]*?)```/g, (_, lang, code) => {
      return `<pre><code>${code.trim()}</code></pre>`;
    });

    // Inline code
    html = html.replace(/`([^`]+)`/g, '<code>$1</code>');

    // Bold
    html = html.replace(/\*\*(.+?)\*\*/g, '<strong>$1</strong>');

    // Italic
    html = html.replace(/\*(.+?)\*/g, '<em>$1</em>');

    // Headers
    html = html.replace(/^#### (.+)$/gm, '<h4>$1</h4>');
    html = html.replace(/^### (.+)$/gm, '<h3>$1</h3>');
    html = html.replace(/^## (.+)$/gm, '<h2>$1</h2>');
    html = html.replace(/^# (.+)$/gm, '<h1>$1</h1>');

    // Unordered lists
    html = html.replace(/^- (.+)$/gm, '<li>$1</li>');
    html = html.replace(/(<li>.*<\/li>\n?)+/g, '<ul>$&</ul>');

    // Blockquotes
    html = html.replace(/^&gt; (.+)$/gm, '<blockquote>$1</blockquote>');

    // Line breaks (but not inside pre)
    html = html.replace(/\n/g, '<br>');

    // Clean up extra <br> in pre blocks
    html = html.replace(/<pre><code>([\s\S]*?)<\/code><\/pre>/g, (match) => {
      return match.replace(/<br>/g, '\n');
    });

    return html;
  }

  // =====================
  // UI HELPERS
  // =====================

  updateChatState() {
    if (!this.chatEl) return;

    if (this.currentSessionId) {
      this.chatEl.classList.remove('no-session');
    } else {
      this.chatEl.classList.add('no-session');
    }
  }

  setStatus(status) {
    this.sessionStatus = status;

    if (!this.statusBadgeEl) return;

    // Remove all status classes
    this.statusBadgeEl.className = 'assistant-status-badge';

    if (!status) {
      this.statusBadgeEl.textContent = '';
      return;
    }

    const labels = {
      active: 'Bereit',
      running: 'Aktiv',
      thinking: 'Denkt...',
      ended: 'Beendet',
      stopped: 'Gestoppt',
      error: 'Fehler'
    };

    this.statusBadgeEl.classList.add(`status-${status}`);
    this.statusBadgeEl.textContent = labels[status] || status;
  }

  autoResizeInput() {
    if (!this.inputEl) return;
    this.inputEl.style.height = 'auto';
    this.inputEl.style.height = Math.min(this.inputEl.scrollHeight, 150) + 'px';
  }

  scrollToBottom() {
    if (!this.messagesEl) return;
    requestAnimationFrame(() => {
      this.messagesEl.scrollTop = this.messagesEl.scrollHeight;
    });
  }

  escapeHtml(text) {
    const div = document.createElement('div');
    div.textContent = text;
    return div.innerHTML;
  }

  async handleTaskHandover(taskContext) {
    // Switch to assistant view
    const assistantTab = document.querySelector('.view-tab[data-view="assistant"]');
    if (assistantTab) assistantTab.click();

    // Ensure initialized
    await this.init();

    // Start new session with task context
    await this.startSession(taskContext);
  }

  showToast(message, type = 'info') {
    window.dispatchEvent(new CustomEvent('toast:show', {
      detail: { message, type }
    }));
  }
}

// Singleton
const assistantManager = new AssistantManager();
export default assistantManager;