// GM Assistant - Claude-powered assistant for Foundry VTT
// Uses ApplicationV2 for Foundry v13 compatibility

const MODULE_ID = 'gm-assistant';
const BRIDGE_URL_DEFAULT = 'http://10.4.2.37:3001';

// Register module settings
Hooks.once('init', () => {
  game.settings.register(MODULE_ID, 'bridgeUrl', {
    name: 'Bridge URL',
    hint: 'URL of the GM Assistant bridge service',
    scope: 'world',
    config: true,
    type: String,
    default: BRIDGE_URL_DEFAULT
  });
});

// Add control button when ready
Hooks.once('ready', () => {
  if (!game.user?.isGM) return;

  console.log('GM Assistant | Module ready');
});

// Add button to scene controls
Hooks.on('getSceneControlButtons', (controls) => {
  if (!game.user?.isGM) return;

  const tokenControls = controls.find(c => c.name === 'token');
  if (tokenControls) {
    tokenControls.tools.push({
      name: 'gm-assistant',
      title: 'GM Assistant',
      icon: 'fas fa-robot',
      button: true,
      onClick: () => GMAssistantApp.show()
    });
  }
});

// GM Assistant Application Window
class GMAssistantApp extends foundry.applications.api.ApplicationV2 {
  static DEFAULT_OPTIONS = {
    id: 'gm-assistant-app',
    classes: ['gm-assistant-window'],
    tag: 'div',
    window: {
      title: 'GM Assistant',
      icon: 'fas fa-robot',
      resizable: true,
      minimizable: true
    },
    position: {
      width: 450,
      height: 500
    }
  };

  static PARTS = {
    main: {
      template: null // We'll build the HTML directly
    }
  };

  // Singleton instance
  static _instance = null;

  static show() {
    if (!this._instance) {
      this._instance = new GMAssistantApp();
    }
    this._instance.render(true);
    return this._instance;
  }

  constructor(options = {}) {
    super(options);
    this.messages = [];
    this.sessionId = null;
    this.isStreaming = false;
    this.currentResponse = '';
  }

  get bridgeUrl() {
    return game.settings.get(MODULE_ID, 'bridgeUrl');
  }

  async _prepareContext(options) {
    return {
      messages: this.messages,
      isStreaming: this.isStreaming
    };
  }

  async _renderHTML(context, options) {
    const html = document.createElement('div');
    html.classList.add('gm-assistant-container');
    html.innerHTML = `
      <div class="gm-assistant-messages" data-messages></div>
      <div class="gm-assistant-input-area">
        <textarea placeholder="Ask Claude anything..." data-input></textarea>
        <div class="button-group">
          <button type="button" class="send" data-send>Send</button>
          <button type="button" class="new-chat" data-new-chat>New Chat</button>
        </div>
      </div>
      <div class="gm-assistant-status" data-status>Ready</div>
    `;
    return html;
  }

  _onRender(context, options) {
    const html = this.element;

    // Get elements
    const messagesEl = html.querySelector('[data-messages]');
    const inputEl = html.querySelector('[data-input]');
    const sendBtn = html.querySelector('[data-send]');
    const newChatBtn = html.querySelector('[data-new-chat]');
    const statusEl = html.querySelector('[data-status]');

    // Store refs
    this._messagesEl = messagesEl;
    this._inputEl = inputEl;
    this._statusEl = statusEl;

    // Render existing messages
    this._renderMessages();

    // Send button
    sendBtn.addEventListener('click', () => this._sendMessage());

    // Enter to send (Shift+Enter for newline)
    inputEl.addEventListener('keydown', (e) => {
      if (e.key === 'Enter' && !e.shiftKey) {
        e.preventDefault();
        this._sendMessage();
      }
    });

    // New chat button
    newChatBtn.addEventListener('click', () => {
      this.messages = [];
      this.sessionId = null;
      this._renderMessages();
      this._setStatus('New conversation started', 'connected');
    });

    // Check bridge health
    this._checkBridgeHealth();
  }

  async _checkBridgeHealth() {
    try {
      const response = await fetch(`${this.bridgeUrl}/api/health`);
      if (response.ok) {
        this._setStatus('Connected to bridge', 'connected');
      } else {
        this._setStatus('Bridge error', 'error');
      }
    } catch (e) {
      this._setStatus('Cannot connect to bridge', 'error');
    }
  }

  _setStatus(text, type = '') {
    if (this._statusEl) {
      this._statusEl.textContent = text;
      this._statusEl.className = 'gm-assistant-status ' + type;
    }
  }

  _renderMessages() {
    if (!this._messagesEl) return;

    this._messagesEl.innerHTML = this.messages.map(msg => {
      const classes = ['gm-assistant-message', msg.type];
      return `<div class="${classes.join(' ')}">${this._escapeHtml(msg.content)}</div>`;
    }).join('');

    // Scroll to bottom
    this._messagesEl.scrollTop = this._messagesEl.scrollHeight;
  }

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

  _addMessage(type, content) {
    this.messages.push({ type, content });
    this._renderMessages();
  }

  _updateLastAssistantMessage(content) {
    const last = this.messages[this.messages.length - 1];
    if (last && last.type === 'assistant') {
      last.content = content;
      this._renderMessages();
    }
  }

  async _sendMessage() {
    const input = this._inputEl;
    const message = input.value.trim();

    if (!message || this.isStreaming) return;

    // Add user message
    this._addMessage('user', message);
    input.value = '';

    // Start streaming
    this.isStreaming = true;
    this.currentResponse = '';
    this._setStatus('Thinking...', '');

    try {
      const response = await fetch(`${this.bridgeUrl}/api/chat`, {
        method: 'POST',
        headers: { 'Content-Type': 'application/json' },
        body: JSON.stringify({
          message: message,
          sessionId: this.sessionId
        })
      });

      if (!response.ok) {
        throw new Error(`Bridge error: ${response.status}`);
      }

      // Add placeholder for assistant response
      this._addMessage('assistant', '');

      // Read SSE stream
      const reader = response.body.getReader();
      const decoder = new TextDecoder();

      while (true) {
        const { done, value } = await reader.read();
        if (done) break;

        const chunk = decoder.decode(value, { stream: true });
        const lines = chunk.split('\n');

        for (const line of lines) {
          if (!line.startsWith('data: ')) continue;

          try {
            const data = JSON.parse(line.slice(6));

            switch (data.type) {
              case 'session':
                this.sessionId = data.sessionId;
                break;

              case 'text':
                this.currentResponse += data.content;
                this._updateLastAssistantMessage(this.currentResponse);
                break;

              case 'tool':
                this._addMessage('tool', `Using: ${data.name}`);
                // Re-add assistant placeholder after tool message
                this._addMessage('assistant', this.currentResponse);
                break;

              case 'done':
                this.sessionId = data.sessionId;
                this._setStatus('Ready', 'connected');
                break;

              case 'error':
                this._addMessage('system', `Error: ${data.message}`);
                break;
            }
          } catch (e) {
            // Skip invalid JSON lines
          }
        }
      }

    } catch (e) {
      console.error('GM Assistant error:', e);
      this._addMessage('system', `Error: ${e.message}`);
      this._setStatus('Error', 'error');
    } finally {
      this.isStreaming = false;
      this._setStatus('Ready', 'connected');
    }
  }
}

// Export for global access
globalThis.GMAssistantApp = GMAssistantApp;