import express from 'express';
import { WebSocketServer } from 'ws';
import { createServer } from 'http';
import { spawn } from 'child_process';
import { v4 as uuidv4 } from 'uuid';
import cors from 'cors';
import { existsSync, readFileSync, readdirSync, statSync } from 'fs';
import { join } from 'path';

const app = express();
app.use(cors());
app.use(express.json());

const PORT = process.env.PORT || 3001;
const HOST = process.env.HOST || '0.0.0.0';

// Store active Claude sessions
const sessions = new Map();

const server = createServer(app);
const wss = new WebSocketServer({ server });

// REST endpoint to list available projects
app.get('/api/projects', (req, res) => {
  const baseDirs = [
    { path: '/projects', name: 'projects', description: 'Development projects' },
    { path: '/docker', name: 'docker', description: 'Docker configurations' },
    { path: '/stacks', name: 'stacks', description: 'Production stacks' }
  ];

  const projects = [];
  for (const dir of baseDirs) {
    if (existsSync(dir.path)) {
      projects.push({ ...dir, type: 'directory' });
    }
  }
  res.json(projects);
});

// Health check
app.get('/api/health', (req, res) => {
  res.json({
    status: 'ok',
    activeSessions: sessions.size,
    timestamp: new Date().toISOString()
  });
});

// Get session history for a project
app.get('/api/history/:project', (req, res) => {
  try {
    const projectPath = decodeURIComponent(req.params.project);
    // Convert project path to Claude's folder naming convention
    const projectFolder = projectPath.replace(/\//g, '-');
    const historyDir = `/home/node/.claude/projects/${projectFolder}`;

    if (!existsSync(historyDir)) {
      return res.json({ messages: [], sessionId: null });
    }

    // Find the most recent non-agent session file
    const files = readdirSync(historyDir)
      .filter(f => f.endsWith('.jsonl') && !f.startsWith('agent-'))
      .map(f => ({
        name: f,
        path: join(historyDir, f),
        mtime: statSync(join(historyDir, f)).mtime
      }))
      .sort((a, b) => b.mtime - a.mtime);

    if (files.length === 0) {
      return res.json({ messages: [], sessionId: null });
    }

    const latestFile = files[0];
    const sessionId = latestFile.name.replace('.jsonl', '');
    const content = readFileSync(latestFile.path, 'utf-8');
    const lines = content.split('\n').filter(l => l.trim());

    const messages = [];
    for (const line of lines) {
      try {
        const event = JSON.parse(line);

        // Parse user messages
        if (event.type === 'user' && event.message?.content) {
          const textContent = event.message.content
            .filter(c => c.type === 'text')
            .map(c => c.text)
            .join('');
          if (textContent && !event.tool_use_result) {
            messages.push({
              type: 'user',
              content: textContent,
              timestamp: event.timestamp || Date.now()
            });
          }
        }

        // Parse assistant messages
        if (event.type === 'assistant' && event.message?.content) {
          for (const block of event.message.content) {
            if (block.type === 'text' && block.text) {
              messages.push({
                type: 'assistant',
                content: block.text,
                timestamp: event.timestamp || Date.now()
              });
            } else if (block.type === 'tool_use') {
              messages.push({
                type: 'tool_use',
                tool: block.name,
                input: block.input,
                toolUseId: block.id,
                timestamp: event.timestamp || Date.now()
              });
            }
          }
        }

        // Parse tool results
        if (event.type === 'user' && event.tool_use_result) {
          messages.push({
            type: 'tool_result',
            content: event.tool_use_result.content,
            toolUseId: event.tool_use_result.tool_use_id,
            isError: event.tool_use_result.is_error || false,
            timestamp: event.timestamp || Date.now()
          });
        }
      } catch (e) {
        // Skip invalid JSON lines
      }
    }

    res.json({ messages, sessionId });
  } catch (err) {
    console.error('Error reading history:', err);
    res.status(500).json({ error: err.message });
  }
});

wss.on('connection', (ws, req) => {
  const sessionId = uuidv4();
  console.log(`[${sessionId}] New WebSocket connection`);

  let claudeProcess = null;
  let currentProject = null;

  const sendToClient = (type, data) => {
    if (ws.readyState === ws.OPEN) {
      ws.send(JSON.stringify({ type, ...data, timestamp: Date.now() }));
    }
  };

  const startClaudeSession = (projectPath, resume = true) => {
    if (claudeProcess) {
      console.log(`[${sessionId}] Killing existing Claude process`);
      claudeProcess.kill();
    }

    currentProject = projectPath;
    console.log(`[${sessionId}] Starting Claude in: ${projectPath} (resume: ${resume})`);

    const args = [
      '-p',
      '--output-format', 'stream-json',
      '--input-format', 'stream-json',
      '--include-partial-messages',
      '--verbose',
      '--dangerously-skip-permissions'
    ];

    // Add continue flag to resume most recent conversation
    if (resume) {
      args.push('--continue');
    }

    claudeProcess = spawn('claude', args, {
      stdio: ['pipe', 'pipe', 'pipe'],
      cwd: projectPath || '/projects',
      env: { ...process.env }
    });

    sessions.set(sessionId, { process: claudeProcess, project: projectPath });

    sendToClient('session_started', {
      sessionId,
      project: projectPath
    });

    // Handle stdout (JSON events)
    let buffer = '';
    claudeProcess.stdout.on('data', (data) => {
      const chunk = data.toString();
      console.log(`[${sessionId}] stdout chunk:`, chunk.substring(0, 200));

      buffer += chunk;
      const lines = buffer.split('\n');
      buffer = lines.pop() || '';

      for (const line of lines) {
        if (line.trim()) {
          console.log(`[${sessionId}] Processing line:`, line.substring(0, 100));
          try {
            const event = JSON.parse(line);
            console.log(`[${sessionId}] Event type:`, event.type);
            sendToClient('claude_event', { event });
          } catch (e) {
            // Non-JSON output, send as raw
            console.log(`[${sessionId}] Raw output:`, line.substring(0, 100));
            sendToClient('raw_output', { content: line });
          }
        }
      }
    });

    // Handle stderr
    claudeProcess.stderr.on('data', (data) => {
      const content = data.toString();
      console.log(`[${sessionId}] stderr:`, content);
      sendToClient('stderr', { content });
    });

    claudeProcess.on('close', (code) => {
      console.log(`[${sessionId}] Claude process exited with code ${code}`);
      sendToClient('session_ended', { code });
      sessions.delete(sessionId);
      claudeProcess = null;
    });

    claudeProcess.on('error', (err) => {
      console.error(`[${sessionId}] Claude process error:`, err);
      sendToClient('error', { message: err.message });
    });
  };

  ws.on('message', (message) => {
    try {
      const data = JSON.parse(message.toString());
      console.log(`[${sessionId}] Received:`, data.type);

      switch (data.type) {
        case 'start_session':
          startClaudeSession(data.project || '/projects', data.resume !== false);
          break;

        case 'user_message':
          if (!claudeProcess) {
            sendToClient('error', { message: 'No active Claude session' });
            return;
          }

          const payload = {
            type: 'user',
            message: {
              role: 'user',
              content: [{ type: 'text', text: data.message }]
            }
          };

          console.log(`[${sessionId}] Sending to Claude:`, data.message.substring(0, 50) + '...');
          claudeProcess.stdin.write(JSON.stringify(payload) + '\n');
          break;

        case 'stop_session':
          if (claudeProcess) {
            claudeProcess.kill();
            claudeProcess = null;
          }
          break;

        default:
          console.log(`[${sessionId}] Unknown message type:`, data.type);
      }
    } catch (e) {
      console.error(`[${sessionId}] Error processing message:`, e);
      sendToClient('error', { message: e.message });
    }
  });

  ws.on('close', () => {
    console.log(`[${sessionId}] WebSocket closed`);
    if (claudeProcess) {
      claudeProcess.kill();
      sessions.delete(sessionId);
    }
  });

  ws.on('error', (err) => {
    console.error(`[${sessionId}] WebSocket error:`, err);
  });
});

server.listen(PORT, HOST, () => {
  console.log(`Claude Web UI Backend running on http://${HOST}:${PORT}`);
  console.log(`WebSocket available at ws://${HOST}:${PORT}`);
});