fs = require('fs');
http = require('http');
url = require('url');
crypto = require('crypto');
path = require('path');
sys = require('sys');
memcached = require('./lib/memcached-v1');
config = require('./lib/config').init((process.argv[2] == null) ? 'config.json' : process.argv[2]);
log = require('./lib/log');

log.init(config);

client = new memcached('localhost:11211');
server = http.createServer(null);
hash = crypto.createHash('md5');
data = new memcached.Chunk();
tag = new memcached.Chunk();
magic = new Buffer('module.exports.flush', 'utf8');
config.node.magicBuffer = new Buffer('module.exports.' + config.node.call, 'utf8');

server.addListener('request', function(request, response) {
	target = path.join(process.cwd(), url.parse(request.url).pathname);

	console.log('Serving ' + target);

	data.assignClient(client);
	data.key = config.memcached.prefix + ':data:' + target;

	tag.assignClient(client);
	tag.key = config.memcached.prefix + ':hash:' + target;

	data.get(function(cached) {
		if (cached && false) {
			console.log('extracting ' + target + ' from memcached');
			tag.get(function(tag) {
				if (request.headers['if-none-match'] == tag) {
					console.log('not modified');
					response.writeHead(304, 'Not modified');
					response.end();
				}
				else {
					console.log('sending cached content');
					response.writeHead(200, 'OK - memcached', { 'ETag' : tag, 'Content-Encoding' : 'utf-8', 'Strict-Transport-Security' : 'max-age=15768000 ; includeSubDomains'});
					response.end(cached);
				}
			});
		}
		else {
			fs.stat(target, function(err, stats) {
				if (err) {
					console.log("stat failed: " + err);
					switch (err) {
						case 2: console.log("no such file or directory");
							response.writeHead(404);
							response.end();
							break;
						case 13:// permission denied
							response.writeHead(403);
							response.end();
							break;
						default:
							response.writeHead(500);
							response.end();
							break;
					}
				}
				else {
					fs.open(target, 'r', 0666, function(err, fd) {
						if(err) {
							response.writeHead(500);
							response.end();
						}
						else {
							scan = (path.extname(target) == '.js');
							dyn = false;
							data.value = new Buffer(stats.size);
							fs.read(fd, data.value, 0, stats.size, 0, function(err, bytesRead) {
								if (bytesRead >= config.node.magicBuffer.length && scan) {
									scan = false;
									if (compareBuffers(data.value, config.node.magicBuffer)) {
										dyn = true;
										fs.close(fd, function() {
											log.append(7, 'Executing node.js module \'' + target + '\'.');
											require(target.substring(0, target.length - 3)).flush(request, response);
										});
									}
								}
								if (bytesRead == stats.size && !scan && !dyn) {
									hash.update(data.value);
									tag.value = hash.digest('base64');
									response.writeHead(200, {'ETag': tag.value});
									response.end(data.value);
									data.value = data.value.toString('binary');
									data.set(3600, function(reponse) {
										log.append(8, 'refreshed ' + data.key);
									});
									tag.set(3600, function(reponse) {
										log.append(8, 'refreshed ' + tag.key + ' ' + tag.value);
									});
								}
							});
						}
					});
				}
			});
		}
	});
});

function compareBuffers(a, b) {
	len = (a.length < b.length) ? a.length : b.length;
	for (i = 0; i < len; i++)
		if (a[i] != b[i])
			return false;
	return true;
}

server.listen(config.server.port, config.server.host);