#include "csoap/http_parser.h"

#include "boost/algorithm/string.hpp"
#include "boost/lexical_cast.hpp"

#include "csoap/http_message.h"

namespace csoap {

HttpParser::HttpParser(HttpMessage* message)
  : message_(message)
  , start_line_parsed_(false)
  , header_parsed_(false)
  , finished_(false) {
}

void HttpParser::Reset() {
  // TODO: Reset parsing state.
}

ErrorCode HttpParser::Parse(const char* data, size_t len) {
  if (header_parsed_) {
    // Add the data to the content.
    message_->AppendContent(data, len);

    if (message_->IsContentFull()) {
      // All content has been read.
      finished_ = true;
    }

    return kNoError;
  }

  pending_data_.append(data, len);
  size_t off = 0;

  while (true) {
    size_t pos = pending_data_.find(kCRLF, off);
    if (pos == std::string::npos) {
      break;
    }

    if (pos == off) {  // End of headers.
      off = pos + 2;  // Skip CRLF.
      header_parsed_ = true;
      break;
    }

    std::string line = pending_data_.substr(off, pos - off);

    if (!start_line_parsed_) {
      start_line_parsed_ = true;
      ErrorCode error = ParseStartLine(line);
      if (error != kNoError) {
        return error;
      }
    } else {
      // Currently, only Content-Length is important to us.
      // Other fields are ignored.
      if (message_->content_length() == kInvalidLength) {
        // Not parsed yet.
        ParseContentLength(line);
      }
    }

    off = pos + 2;  // Skip CRLF.
  }

  if (header_parsed_) {
    // Headers just ended.

    if (message_->content_length() == kInvalidLength) {
      // No Content-Length?
      return kHttpContentLengthError;
    }

    message_->AppendContent(pending_data_.substr(off));

    if (message_->IsContentFull()) {
      // All content has been read.
      finished_ = true;
    }
  } else {
    // Save the unparsed piece for next parsing.
    pending_data_ = pending_data_.substr(off);
  }

  return kNoError;
}

void HttpParser::ParseContentLength(const std::string& line) {
  size_t pos = line.find(':');
  if (pos == std::string::npos) {
    return;
  }

  std::string name = line.substr(0, pos);

  if (boost::iequals(name, kContentLengthName)) {
    ++pos;  // Skip ':'.
    while (line[pos] == ' ') {  // Skip spaces.
      ++pos;
    }

    std::string value = line.substr(pos);

    try {
      message_->set_content_length(boost::lexical_cast<size_t>(value));
    } catch (boost::bad_lexical_cast&) {
      // TODO
    }
  }
}

}  // namespace csoap