const fs = require('fs');
const path = require('path');
const net = require('net');
const { handleCommand } = require('./commands');

const asciiLogo = `    +       **==+=                                                       ===                    
   ===+   %=========           +======          ++*  =*==+       =====+=+===        ++====*+    
  ===+    ===    +===       ============        ==========*    ==========-        ============  
 ===+    %===     +===     ===*       ====      ====+         ===      +===     %===       +=== 
 ===#    %===     ====    ===*         ===#     ===+         *==#       ===     ===         ===*
%===     %===     ====   #===          ====     ===           ==+       ===    %==+*********====
 ===#    %===     +===   -==+          *===     ==+           +===    *===#    *================
 ===+    %===    ====*   #===          ====     ==+             ========+      %==+             
  ====+  %===   +===+     ===*         ===#     ==+           ===               ===             
   *===============       *====       ====      ==+           ===+              *===+       ===*
      =*======*+            ============#       ==+            ============+      ============% 
         %===                 =+====++          **#          ===+=  ===++====       =*====++    
         %===                                                ===           ===                  
         %===                                                ===+         ====                  
         %===                                                 ===============                   
                                                                 *=======                       `;

const contentTypes = {
  '.html': 'text/html; charset=utf-8',
  '.css': 'text/css; charset=utf-8',
  '.js': 'application/javascript; charset=utf-8',
  '.svg': 'image/svg+xml',
  '.png': 'image/png',
  '.jpg': 'image/jpeg',
  '.jpeg': 'image/jpeg',
  '.ico': 'image/x-icon',
  '.json': 'application/json; charset=utf-8',
};

const buildPath = (requestedPath) => {
  let safePath = requestedPath.split('?')[0].split('#')[0];
  safePath = decodeURIComponent(safePath);
  safePath = safePath.replace(/^\//, '');
  if (!safePath || safePath === '') {
    return path.join(__dirname, 'index.html');
  }

  const candidate = path.join(__dirname, safePath);
  if (!candidate.startsWith(__dirname)) {
    return null;
  }
  return candidate;
};

const isHttpRequest = (chunk) => {
  return /^(GET|POST|HEAD|PUT|DELETE|OPTIONS|PATCH|TRACE|CONNECT)\s+/i.test(chunk);
};

const sendHttpResponse = (socket, statusCode, statusText, headers, body) => {
  const head = [`HTTP/1.1 ${statusCode} ${statusText}`];
  for (const [key, value] of Object.entries(headers)) {
    head.push(`${key}: ${value}`);
  }
  head.push('Connection: close');
  head.push('');
  if (body) {
    socket.end(head.join('\r\n') + '\r\n' + body);
  } else {
    socket.end(head.join('\r\n') + '\r\n');
  }
};

const handleHttp = (socket, requestData) => {
  const [requestLine] = requestData.split('\r\n');
  const [method, requestPath] = requestLine.split(' ');
  const filePath = buildPath(requestPath);

  if (!filePath) {
    return sendHttpResponse(socket, 400, 'Bad Request', { 'Content-Type': 'text/plain; charset=utf-8' }, '400 Bad Request');
  }

  fs.stat(filePath, (err, stats) => {
    if (err || !stats.isFile()) {
      return sendHttpResponse(socket, 404, 'Not Found', { 'Content-Type': 'text/plain; charset=utf-8' }, '404 Not Found');
    }

    fs.readFile(filePath, (readErr, data) => {
      if (readErr) {
        return sendHttpResponse(socket, 500, 'Internal Server Error', { 'Content-Type': 'text/plain; charset=utf-8' }, '500 Internal Server Error');
      }

      const ext = path.extname(filePath).toLowerCase();
      const contentType = contentTypes[ext] || 'application/octet-stream';
      sendHttpResponse(socket, 200, 'OK', { 'Content-Type': contentType, 'Content-Length': Buffer.byteLength(data) }, data);
    });
  });
};

const createTerminalSession = (socket, initialData) => {
  socket.write(asciiLogo + '\r\n\r\n');
  socket.write('Open-Source & Community first Cloud Provider (/help for assistance)\r\n');
  socket.write('phorge> ');

  let buffer = '';
  if (initialData) {
    buffer += initialData;
  }

  const flushLines = () => {
    let index;
    while ((index = buffer.indexOf('\n')) !== -1) {
      let line = buffer.slice(0, index).replace(/\r$/, '');
      buffer = buffer.slice(index + 1);
      handleCommand(socket, line);
    }
  };

  socket.on('data', (chunk) => {
    buffer += chunk.toString('utf8');
    flushLines();
  });

  socket.on('error', () => {
    socket.destroy();
  });
};

const server = net.createServer((socket) => {
  socket.setEncoding('utf8');
  let hasHandled = false;

  const onFirstData = (chunk) => {
    if (hasHandled) return;
    hasHandled = true;
    const data = chunk.toString('utf8');
    if (isHttpRequest(data)) {
      handleHttp(socket, data);
    } else {
      createTerminalSession(socket, data);
    }
  };

  socket.once('data', onFirstData);

  socket.on('error', () => {
    socket.destroy();
  });
});

const PORT = process.env.PORT || 80;
server.listen(PORT, () => {
  console.log(`Phorge server listening on port ${PORT}`);
});