/*
 * Copyright (C) 2012 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
 *
 * See COPYING for license information.
 *
 */

#include "JsonScgiPeer.h"
#include "JsonScgiServer.h"
#include "QtJson.h"
#include <QtCore/QTimer>
#include <QtCore/QStringList>
#include <cstring>

using namespace QtJson;

JsonScgiPeer::JsonScgiPeer(QTcpSocket *connection, JsonScgiServer *parent) :
	QObject(parent),
	m_connection(connection),
	m_server(parent),
	m_jsonOffset(0),
	m_jsonLength(0),
	m_https(false)
{
	if (!connection->isOpen())
		QTimer::singleShot(0, this, SLOT(disconnected()));
	if (connection->bytesAvailable() > 0)
		QTimer::singleShot(0, this, SLOT(readyRead()));
	connect(connection, SIGNAL(disconnected()), this, SLOT(disconnected()));
	connect(connection, SIGNAL(readyRead()), this, SLOT(readyRead()));
}

JsonScgiPeer::~JsonScgiPeer()
{
	m_connection->deleteLater();
}

void JsonScgiPeer::sendResponse(const QVariantMap &response)
{
	m_outputBuffer = "Status: 200 OK\r\nContent-Type: application/json\r\n"
			 "Set-Cookie: JSONSCGIQTSESSION=" + m_sessionCookie.toAscii() + "; path=/; expires=" +
			 QLocale("C").toString(m_server->cookieExpiration(m_sessionCookie), "ddd, dd MMM yyyy hh:mm:ss").toAscii() +
			 " GMT; HttpOnly" + (m_https ? "; secure" : "") + "\r\n\r\n" + Json::serialize(response) + "\n";
	QTimer::singleShot(0, this, SLOT(readyWrite()));
}

void JsonScgiPeer::die()
{
	m_connection->close();
}

void JsonScgiPeer::notFound()
{
	m_outputBuffer = "Status: 404 Not Found\r\nContent-Type: text/plain\r\n\r\nThese aren't the droids you're looking for.\n";
	QTimer::singleShot(0, this, SLOT(readyWrite()));
}

// Implements http://python.ca/scgi/protocol.txt
void JsonScgiPeer::parseScgiHeader()
{
	int i = m_inputBuffer.indexOf(':');
	if (i == -1)
		return;
	bool ok;
	m_jsonOffset = m_inputBuffer.left(i).toUInt(&ok) + 2 + i;
	if (!ok)
		return;

	if (static_cast<unsigned int>(m_inputBuffer.size()) < m_jsonOffset)
		return;

	++i;

	// Sure, hate me. But sometimes C strings are just simpler,
	// especially when you're dealing with a null-terminated spec.
	// Besides, Qt ensures that data() will be null terminated so
	// that we don't risk any overruns.
	const char *key, *value;
	const char *data = m_inputBuffer.constData();
	while (static_cast<unsigned int>(i) < m_jsonOffset) {
		if (data[i] == ',')
			break;
		key = data + i;
		i += strlen(key) + 1;
		if (static_cast<unsigned int>(i) >= m_jsonOffset)
			break;
		value = data + i;
		i += strlen(value) + 1;

		if (!strcmp(key, "CONTENT_LENGTH"))
			m_jsonLength = QString(value).toUInt();
		else if (!strcmp(key, "REQUEST_URI"))
			m_url.setUrl(value);
		else if (!strcmp(key, "HTTP_COOKIE")) {
			QString cookieList(value);
			QStringList cookies = cookieList.split(';', QString::SkipEmptyParts);
			foreach (const QString &cookie, cookies) {
				QStringList cookiePair = cookie.split('=', QString::SkipEmptyParts);
				if (cookiePair.size() != 2)
					continue;
				if (cookiePair.at(0).trimmed() == "JSONSCGIQTSESSION") {
					m_sessionCookie = cookiePair.at(1);
					break;
				}
			}
		} else if (!strcmp(key, "HTTPS"))
			m_https = true;
	}

	if (!m_jsonLength)
		m_server->newWebRequest(m_url, m_sessionCookie, QVariantMap(), *this);
	else if (static_cast<unsigned int>(m_inputBuffer.size()) >= m_jsonOffset + m_jsonLength)
		parseJsonBody();
}

void JsonScgiPeer::parseJsonBody()
{
	if (static_cast<unsigned int>(m_inputBuffer.size()) < m_jsonOffset + m_jsonLength)
		return;

	bool ok;
	const QVariantMap result = Json::parse(m_inputBuffer.data() + m_jsonOffset, ok).toMap();
	if (!ok) {
		notFound();
		return;
	}
	m_server->newWebRequest(m_url, m_sessionCookie, result, *this);
}

void JsonScgiPeer::disconnected()
{
	deleteLater();
}

void JsonScgiPeer::readyRead()
{
	if (m_inputBuffer.size() + m_connection->bytesAvailable() > 100 * 1024 * 1024 /* 100 megs */) {
		die();
		return;
	}
	m_inputBuffer.append(m_connection->readAll());
	if (m_connection->bytesAvailable())
		QTimer::singleShot(0, this, SLOT(readyRead()));

	if (m_jsonOffset && m_jsonLength && static_cast<unsigned int>(m_inputBuffer.size()) >= m_jsonLength + m_jsonOffset)
		parseJsonBody();
	else
		parseScgiHeader();
}

void JsonScgiPeer::readyWrite()
{
	int writen = m_connection->write(m_outputBuffer);
	if (writen == -1) {
		die();
		return;
	}
	m_outputBuffer.remove(0, writen);
	if (m_outputBuffer.size())
		QTimer::singleShot(0, this, SLOT(readyWrite()));
	else
		m_connection->disconnectFromHost();
}