#include "IMFHeader.h"
#include "Exception.h"

namespace coreutils {

   IMFHeader::IMFHeader(StreamReader &reader) : Parser(reader) {}

   Parser::Status IMFHeader::parse() {
      MString &buffer = reader.getBuffer();

      switch (state) {

       case NAME: {
          if (buffer.eod())
             return Status::INCOMPLETE;
          if (buffer.getChar() == '\r') {
             // ZString::getLength() is already cursor-relative.
             if (buffer.getLength() < 2)
                return Status::INCOMPLETE;
             if (!buffer.ifNext(ZString("\r\n")))
                throw coreutils::Exception("IMFHeader: expected CRLF at end of header block.");
             return Status::COMPLETE;
          }
          name << buffer.getTokenInclude("ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz-0123456789");
          if (buffer.eod())
             return Status::INCOMPLETE;
          if (!buffer.ifNext(ZString(":")))
             throw coreutils::Exception("IMFHeader: expected ':' in header name.");
          state = SKIP_SPACE;
          return Status::DATA_AVAIL;
       }

       case SKIP_SPACE:
          while (!buffer.eod() && buffer.getChar() == ' ')
             buffer.nextChar();
          if (buffer.eod())
             return Status::INCOMPLETE;
          state = FIELD;
          return Status::DATA_AVAIL;

       case FIELD:
          field << buffer.getTokenExclude("\r\n");
          // Need 2 bytes buffered to reliably test for "\r\n" - eod() (a
          // 1-byte check) would wrongly treat a lone trailing \r as
          // malformed instead of "wait for the \n". Same bug class already
          // fixed once in IMFBoundary's TAIL state.
          if (buffer.getLength() < 2)
             return Status::INCOMPLETE;
          if (!buffer.ifNext(ZString("\r\n")))
             throw coreutils::Exception("IMFHeader: expected CRLF at end of header field.");
          state = FOLD_CHECK;
          return Status::DATA_AVAIL;

       case FOLD_CHECK:
          if (buffer.eod())
             return Status::INCOMPLETE;
          if (buffer.getChar() == ' ' || buffer.getChar() == '\t') {
             buffer.nextChar();
             field << " ";
             state = SKIP_SPACE;
             return Status::DATA_AVAIL;
          }
          commitField();
          state = NAME;
          return Status::DATA_AVAIL;

      }
      throw coreutils::Exception("IMFHeader: unreachable state.");
   }

   void IMFHeader::commitField() {
      headers[name] = field;
      name = MString();
      field = MString();
   }

   std::map<MString, MString> &IMFHeader::getHeaders() {
      return headers;
   }

}