/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
/**
 * Copyright (c) 2013-2016, Regents of the University of California.
 *
 * This file is part of ChronoShare, a decentralized file sharing application over NDN.
 *
 * ChronoShare is free software: you can redistribute it and/or modify it under the terms
 * of the GNU General Public License as published by the Free Software Foundation, either
 * version 3 of the License, or (at your option) any later version.
 *
 * ChronoShare is distributed in the hope that it will be useful, but WITHOUT ANY
 * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
 * PARTICULAR PURPOSE.  See the GNU General Public License for more details.
 *
 * You should have received copies of the GNU General Public License along with
 * ChronoShare, e.g., in COPYING.md file.  If not, see <http://www.gnu.org/licenses/>.
 *
 * See AUTHORS.md for complete list of ChronoShare authors and contributors.
 */
//
// request_parser.cpp
// ~~~~~~~~~~~~~~~~~~
//
// Copyright (c) 2003-2012 Christopher M. Kohlhoff (chris at kohlhoff dot com)
//
// Distributed under the Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
//

#include "request_parser.hpp"
#include "request.hpp"

namespace http {
namespace server {

request_parser::request_parser()
  : state_(method_start)
{
}

void
request_parser::reset()
{
  state_ = method_start;
}

boost::tribool
request_parser::consume(request& req, char input)
{
  switch (state_) {
    case method_start:
      if (!is_char(input) || is_ctl(input) || is_tspecial(input)) {
        return false;
      }
      else {
        state_ = method;
        req.method.push_back(input);
        return boost::indeterminate;
      }
    case method:
      if (input == ' ') {
        state_ = uri;
        return boost::indeterminate;
      }
      else if (!is_char(input) || is_ctl(input) || is_tspecial(input)) {
        return false;
      }
      else {
        req.method.push_back(input);
        return boost::indeterminate;
      }
    case uri:
      if (input == ' ') {
        state_ = http_version_h;
        return boost::indeterminate;
      }
      else if (is_ctl(input)) {
        return false;
      }
      else {
        req.uri.push_back(input);
        return boost::indeterminate;
      }
    case http_version_h:
      if (input == 'H') {
        state_ = http_version_t_1;
        return boost::indeterminate;
      }
      else {
        return false;
      }
    case http_version_t_1:
      if (input == 'T') {
        state_ = http_version_t_2;
        return boost::indeterminate;
      }
      else {
        return false;
      }
    case http_version_t_2:
      if (input == 'T') {
        state_ = http_version_p;
        return boost::indeterminate;
      }
      else {
        return false;
      }
    case http_version_p:
      if (input == 'P') {
        state_ = http_version_slash;
        return boost::indeterminate;
      }
      else {
        return false;
      }
    case http_version_slash:
      if (input == '/') {
        req.http_version_major = 0;
        req.http_version_minor = 0;
        state_ = http_version_major_start;
        return boost::indeterminate;
      }
      else {
        return false;
      }
    case http_version_major_start:
      if (is_digit(input)) {
        req.http_version_major = req.http_version_major * 10 + input - '0';
        state_ = http_version_major;
        return boost::indeterminate;
      }
      else {
        return false;
      }
    case http_version_major:
      if (input == '.') {
        state_ = http_version_minor_start;
        return boost::indeterminate;
      }
      else if (is_digit(input)) {
        req.http_version_major = req.http_version_major * 10 + input - '0';
        return boost::indeterminate;
      }
      else {
        return false;
      }
    case http_version_minor_start:
      if (is_digit(input)) {
        req.http_version_minor = req.http_version_minor * 10 + input - '0';
        state_ = http_version_minor;
        return boost::indeterminate;
      }
      else {
        return false;
      }
    case http_version_minor:
      if (input == '\r') {
        state_ = expecting_newline_1;
        return boost::indeterminate;
      }
      else if (is_digit(input)) {
        req.http_version_minor = req.http_version_minor * 10 + input - '0';
        return boost::indeterminate;
      }
      else {
        return false;
      }
    case expecting_newline_1:
      if (input == '\n') {
        state_ = header_line_start;
        return boost::indeterminate;
      }
      else {
        return false;
      }
    case header_line_start:
      if (input == '\r') {
        state_ = expecting_newline_3;
        return boost::indeterminate;
      }
      else if (!req.headers.empty() && (input == ' ' || input == '\t')) {
        state_ = header_lws;
        return boost::indeterminate;
      }
      else if (!is_char(input) || is_ctl(input) || is_tspecial(input)) {
        return false;
      }
      else {
        req.headers.push_back(header());
        req.headers.back().name.push_back(input);
        state_ = header_name;
        return boost::indeterminate;
      }
    case header_lws:
      if (input == '\r') {
        state_ = expecting_newline_2;
        return boost::indeterminate;
      }
      else if (input == ' ' || input == '\t') {
        return boost::indeterminate;
      }
      else if (is_ctl(input)) {
        return false;
      }
      else {
        state_ = header_value;
        req.headers.back().value.push_back(input);
        return boost::indeterminate;
      }
    case header_name:
      if (input == ':') {
        state_ = space_before_header_value;
        return boost::indeterminate;
      }
      else if (!is_char(input) || is_ctl(input) || is_tspecial(input)) {
        return false;
      }
      else {
        req.headers.back().name.push_back(input);
        return boost::indeterminate;
      }
    case space_before_header_value:
      if (input == ' ') {
        state_ = header_value;
        return boost::indeterminate;
      }
      else {
        return false;
      }
    case header_value:
      if (input == '\r') {
        state_ = expecting_newline_2;
        return boost::indeterminate;
      }
      else if (is_ctl(input)) {
        return false;
      }
      else {
        req.headers.back().value.push_back(input);
        return boost::indeterminate;
      }
    case expecting_newline_2:
      if (input == '\n') {
        state_ = header_line_start;
        return boost::indeterminate;
      }
      else {
        return false;
      }
    case expecting_newline_3:
      return (input == '\n');
    default:
      return false;
  }
}

bool
request_parser::is_char(int c)
{
  return c >= 0 && c <= 127;
}

bool
request_parser::is_ctl(int c)
{
  return (c >= 0 && c <= 31) || (c == 127);
}

bool
request_parser::is_tspecial(int c)
{
  switch (c) {
    case '(':
    case ')':
    case '<':
    case '>':
    case '@':
    case ',':
    case ';':
    case ':':
    case '\\':
    case '"':
    case '/':
    case '[':
    case ']':
    case '?':
    case '=':
    case '{':
    case '}':
    case ' ':
    case '\t':
      return true;
    default:
      return false;
  }
}

bool
request_parser::is_digit(int c)
{
  return c >= '0' && c <= '9';
}

} // namespace server
} // namespace http