/**
 * Chat — message input + conversation view + streaming
 */

import { sendMessage } from '../app.js';

let messagesEl;
let inputEl;
let sendBtn;
let streamBtn;
let indicatorEl;
let streamingBubble = null;

// Minimal markdown renderer
function renderMarkdown(text) {
  let html = text
    // Code blocks
    .replace(/```(\w*)\n([\s\S]*?)```/g, '<pre><code>$2</code></pre>')
    // Inline code
    .replace(/`([^`]+)`/g, '<code>$1</code>')
    // Headers
    .replace(/^### (.+)$/gm, '<h3>$1</h3>')
    .replace(/^## (.+)$/gm, '<h2>$1</h2>')
    .replace(/^# (.+)$/gm, '<h1>$1</h1>')
    // Bold
    .replace(/\*\*(.+?)\*\*/g, '<strong>$1</strong>')
    // Lists
    .replace(/^\- (.+)$/gm, '<li>$1</li>')
    .replace(/^\* (.+)$/gm, '<li>$1</li>')
    // Paragraphs (double newlines)
    .replace(/\n\n/g, '</p><p>')
    // Single newlines
    .replace(/\n/g, '<br>');

  // Wrap loose <li> in <ul>
  html = html.replace(/(<li>.*?<\/li>)/gs, '<ul>$1</ul>');
  html = html.replace(/<\/ul>\s*<ul>/g, '');

  return `<p>${html}</p>`;
}

export function initChat() {
  const main = document.getElementById('main');

  main.innerHTML = `
    <div class="chat-messages" id="chat-messages">
      <div class="chat-empty">
        <div class="icon">&#9881;</div>
        <p>Select or create a session to start</p>
      </div>
    </div>
    <div class="event-log-panel" id="event-log-panel"></div>
    <div class="chat-input-area">
      <div class="chat-input-wrapper">
        <textarea id="chat-input" placeholder="Send a message..." rows="1" disabled></textarea>
        <button class="btn btn-primary" id="btn-send" disabled>Send</button>
        <button class="btn" id="btn-stream" disabled title="Send with SSE streaming">Stream</button>
      </div>
    </div>
  `;

  messagesEl = document.getElementById('chat-messages');
  inputEl = document.getElementById('chat-input');
  sendBtn = document.getElementById('btn-send');
  streamBtn = document.getElementById('btn-stream');

  // Auto-resize textarea
  inputEl.addEventListener('input', () => {
    inputEl.style.height = 'auto';
    inputEl.style.height = Math.min(inputEl.scrollHeight, 160) + 'px';
  });

  // Send
  sendBtn.addEventListener('click', () => doSend(false));
  streamBtn.addEventListener('click', () => doSend(true));

  // Keyboard shortcuts
  inputEl.addEventListener('keydown', (e) => {
    if (e.key === 'Enter' && !e.shiftKey) {
      e.preventDefault();
      doSend(false);
    }
    if (e.key === 'Enter' && e.ctrlKey) {
      e.preventDefault();
      doSend(true);
    }
  });
}

function doSend(stream) {
  const text = inputEl.value.trim();
  if (!text) return;
  inputEl.value = '';
  inputEl.style.height = 'auto';
  sendMessage(text, stream);
}

export function addMessage(role, content) {
  // Remove empty state
  const empty = messagesEl.querySelector('.chat-empty');
  if (empty) empty.remove();

  // Remove streaming bubble if finalizing
  if (role === 'assistant' && streamingBubble) {
    streamingBubble.remove();
    streamingBubble = null;
  }

  const div = document.createElement('div');
  div.className = `message ${role}`;

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

  messagesEl.appendChild(div);
  messagesEl.scrollTop = messagesEl.scrollHeight;
}

export function setStreamingContent(content, agent) {
  // Remove empty state
  const empty = messagesEl.querySelector('.chat-empty');
  if (empty) empty.remove();

  if (!streamingBubble) {
    streamingBubble = document.createElement('div');
    streamingBubble.className = 'message assistant';
    messagesEl.appendChild(streamingBubble);
  }

  let badgeHtml = '';
  if (agent) {
    badgeHtml = `<span class="agent-badge role-badge ${agent}">${agent}</span><br>`;
  }
  streamingBubble.innerHTML = badgeHtml + renderMarkdown(content);
  messagesEl.scrollTop = messagesEl.scrollHeight;
}

export function clearChat() {
  if (!messagesEl) return;
  streamingBubble = null;
  messagesEl.innerHTML = `
    <div class="chat-empty">
      <div class="icon">&#9881;</div>
      <p>Select or create a session to start</p>
    </div>
  `;
}

export function setInputEnabled(enabled) {
  if (!inputEl) return;
  inputEl.disabled = !enabled;
  sendBtn.disabled = !enabled;
  streamBtn.disabled = !enabled;
  if (enabled) inputEl.focus();
}

export function showExecutionIndicator(text) {
  hideExecutionIndicator();

  const empty = messagesEl.querySelector('.chat-empty');
  if (empty) empty.remove();

  indicatorEl = document.createElement('div');
  indicatorEl.className = 'execution-indicator';
  indicatorEl.innerHTML = `<div class="spinner"></div><span>${text || 'Executing...'}</span>`;
  messagesEl.appendChild(indicatorEl);
  messagesEl.scrollTop = messagesEl.scrollHeight;
}

export function hideExecutionIndicator() {
  if (indicatorEl) {
    indicatorEl.remove();
    indicatorEl = null;
  }
}