/*
* Sketchy HTTP client
* (C) 2013,2016 Jack Lloyd
*
* Botan is released under the Simplified BSD License (see license.txt)
*/

#include <botan/http_util.h>
#include <botan/parsing.h>
#include <botan/hex.h>
#include <botan/internal/stl_util.h>
#include <sstream>

#if defined(BOTAN_HAS_BOOST_ASIO)

  /*
  * We don't need serial port support anyway, and asking for it
  * causes macro conflicts with Darwin's termios.h when this
  * file is included in the amalgamation. GH #350
  */
  #define BOOST_ASIO_DISABLE_SERIAL_PORT
  #include <boost/asio.hpp>

#elif defined(BOTAN_TARGET_OS_HAS_SOCKETS)
  #include <sys/types.h>
  #include <sys/socket.h>
  #include <netdb.h>
  #include <unistd.h>
#else
  #warning "No network support enabled in http_util"
#endif

namespace Botan {

namespace HTTP {

namespace {

/*
* Connect to a host, write some bytes, then read until the server
* closes the socket.
*/
std::string http_transact(const std::string& hostname,
                          const std::string& message)
   {
#if defined(BOTAN_HAS_BOOST_ASIO)
   using namespace boost::asio::ip;

   boost::asio::ip::tcp::iostream tcp;

   tcp.connect(hostname, "http");

   if(!tcp)
      throw HTTP_Error("HTTP connection to " + hostname + " failed");

   tcp << message;
   tcp.flush();

   std::ostringstream oss;
   oss << tcp.rdbuf();

   return oss.str();
#elif defined(BOTAN_TARGET_OS_HAS_SOCKETS)

   hostent* host_addr = ::gethostbyname(hostname.c_str());
   uint16_t port = 80;

   if(!host_addr)
      throw HTTP_Error("Name resolution failed for " + hostname);

   if(host_addr->h_addrtype != AF_INET) // FIXME
      throw HTTP_Error("Hostname " + hostname + " resolved to non-IPv4 address");

   struct socket_raii {
      socket_raii(int fd) : m_fd(fd) {}
      ~socket_raii() { ::close(m_fd); }
      int m_fd;
      };

   int fd = ::socket(PF_INET, SOCK_STREAM, 0);
   if(fd == -1)
      throw HTTP_Error("Unable to create TCP socket");
   socket_raii raii(fd);

   sockaddr_in socket_info;
   ::memset(&socket_info, 0, sizeof(socket_info));
   socket_info.sin_family = AF_INET;
   socket_info.sin_port = htons(port);

   ::memcpy(&socket_info.sin_addr,
            host_addr->h_addr,
            host_addr->h_length);

   socket_info.sin_addr = *reinterpret_cast<struct in_addr*>(host_addr->h_addr); // FIXME

   if(::connect(fd, reinterpret_cast<sockaddr*>(&socket_info), sizeof(struct sockaddr)) != 0)
      throw HTTP_Error("HTTP connection to " + hostname + " failed");

   size_t sent_so_far = 0;
   while(sent_so_far != message.size())
      {
      size_t left = message.size() - sent_so_far;
      ssize_t sent = ::write(fd, &message[sent_so_far], left);

      if(sent < 0)
         throw HTTP_Error("write to HTTP server failed, error '" + std::string(::strerror(errno)) + "'");
      else
         sent_so_far += static_cast<size_t>(sent);
      }

   std::ostringstream oss;
   std::vector<char> buf(1024); // arbitrary size
   while(true)
      {
      ssize_t got = ::read(fd, buf.data(), buf.size());

      if(got < 0)
         throw HTTP_Error("read from HTTP server failed, error '" + std::string(::strerror(errno)) + "'");
      else if(got > 0)
         oss.write(buf.data(), static_cast<std::streamsize>(got));
      else
         break; // EOF
      }
   return oss.str();

#else
   throw HTTP_Error("Cannot connect to " + hostname + ": network code disabled in build");
#endif
   }

}

std::string url_encode(const std::string& in)
   {
   std::ostringstream out;

   for(auto c : in)
      {
      if(c >= 'A' && c <= 'Z')
         out << c;
      else if(c >= 'a' && c <= 'z')
         out << c;
      else if(c >= '0' && c <= '9')
         out << c;
      else if(c == '-' || c == '_' || c == '.' || c == '~')
         out << c;
      else
         out << '%' << hex_encode(reinterpret_cast<byte*>(&c), 1);
      }

   return out.str();
   }

std::ostream& operator<<(std::ostream& o, const Response& resp)
   {
   o << "HTTP " << resp.status_code() << " " << resp.status_message() << "\n";
   for(auto h : resp.headers())
      o << "Header '" << h.first << "' = '" << h.second << "'\n";
   o << "Body " << std::to_string(resp.body().size()) << " bytes:\n";
   o.write(reinterpret_cast<const char*>(&resp.body()[0]), resp.body().size());
   return o;
   }

Response http_sync(http_exch_fn http_transact,
                   const std::string& verb,
                   const std::string& url,
                   const std::string& content_type,
                   const std::vector<byte>& body,
                   size_t allowable_redirects)
   {
   if(url.empty())
      throw HTTP_Error("URL empty");

   const auto protocol_host_sep = url.find("://");
   if(protocol_host_sep == std::string::npos)
      throw HTTP_Error("Invalid URL '" + url + "'");

   const auto host_loc_sep = url.find('/', protocol_host_sep + 3);

   std::string hostname, loc;

   if(host_loc_sep == std::string::npos)
      {
      hostname = url.substr(protocol_host_sep + 3, std::string::npos);
      loc = "/";
      }
   else
      {
      hostname = url.substr(protocol_host_sep + 3, host_loc_sep-protocol_host_sep-3);
      loc = url.substr(host_loc_sep, std::string::npos);
      }

   std::ostringstream outbuf;

   outbuf << verb << " " << loc << " HTTP/1.0\r\n";
   outbuf << "Host: " << hostname << "\r\n";

   if(verb == "GET")
      {
      outbuf << "Accept: */*\r\n";
      outbuf << "Cache-Control: no-cache\r\n";
      }
   else if(verb == "POST")
      outbuf << "Content-Length: " << body.size() << "\r\n";

   if(!content_type.empty())
      outbuf << "Content-Type: " << content_type << "\r\n";
   outbuf << "Connection: close\r\n\r\n";
   outbuf.write(reinterpret_cast<const char*>(body.data()), body.size());

   std::istringstream io(http_transact(hostname, outbuf.str()));

   std::string line1;
   std::getline(io, line1);
   if(!io || line1.empty())
      throw HTTP_Error("No response");

   std::stringstream response_stream(line1);
   std::string http_version;
   unsigned int status_code;
   std::string status_message;

   response_stream >> http_version >> status_code;

   std::getline(response_stream, status_message);

   if(!response_stream || http_version.substr(0,5) != "HTTP/")
      throw HTTP_Error("Not an HTTP response");

   std::map<std::string, std::string> headers;
   std::string header_line;
   while (std::getline(io, header_line) && header_line != "\r")
      {
      auto sep = header_line.find(": ");
      if(sep == std::string::npos || sep > header_line.size() - 2)
         throw HTTP_Error("Invalid HTTP header " + header_line);
      const std::string key = header_line.substr(0, sep);

      if(sep + 2 < header_line.size() - 1)
         {
         const std::string val = header_line.substr(sep + 2, (header_line.size() - 1) - (sep + 2));
         headers[key] = val;
         }
      }

   if(status_code == 301 && headers.count("Location"))
      {
      if(allowable_redirects == 0)
         throw HTTP_Error("HTTP redirection count exceeded");
      return GET_sync(headers["Location"], allowable_redirects - 1);
      }

   std::vector<byte> resp_body;
   std::vector<byte> buf(4096);
   while(io.good())
      {
      io.read(reinterpret_cast<char*>(buf.data()), buf.size());
      resp_body.insert(resp_body.end(), buf.data(), &buf[io.gcount()]);
      }

   const std::string header_size = search_map(headers, std::string("Content-Length"));

   if(!header_size.empty())
      {
      if(resp_body.size() != to_u32bit(header_size))
         throw HTTP_Error("Content-Length disagreement, header says " +
                          header_size + " got " + std::to_string(resp_body.size()));
      }

   return Response(status_code, status_message, resp_body, headers);
   }

Response http_sync(const std::string& verb,
                   const std::string& url,
                   const std::string& content_type,
                   const std::vector<byte>& body,
                   size_t allowable_redirects)
   {
   return http_sync(
      http_transact,
      verb,
      url,
      content_type,
      body,
      allowable_redirects);
   }

Response GET_sync(const std::string& url, size_t allowable_redirects)
   {
   return http_sync("GET", url, "", std::vector<byte>(), allowable_redirects);
   }

Response POST_sync(const std::string& url,
                   const std::string& content_type,
                   const std::vector<byte>& body,
                   size_t allowable_redirects)
   {
   return http_sync("POST", url, content_type, body, allowable_redirects);
   }

}

}