#include "IMFBoundary.h"
#include "Exception.h"

namespace coreutils {

   IMFBoundary::IMFBoundary(StreamReader &reader, ZString boundary) : Parser(reader), boundary(boundary) {}

   Parser::Status IMFBoundary::parse() {
      MString &buffer = reader.getBuffer();
      switch (state) {

       case PREFIX: {
          MString marker;
          marker << "\r\n--";
          marker << boundary;
          int pos = buffer.find(marker);
          if (pos < 0)
             return Status::INCOMPLETE;
          if (!buffer.ifNext(marker))
             throw coreutils::Exception("IMFBoundary: boundary marker vanished between find and ifNext.");
          state = TAIL;
          return Status::DATA_AVAIL;
       }

       case TAIL:
          // ZString::getLength() is already cursor-relative (bytes remaining
          // from the cursor to the end) - do not subtract the cursor offset
          // again here.
          if (buffer.getLength() < 2)
             return Status::INCOMPLETE;
          if (buffer.ifNext(ZString("--"))) {
             last = true;
             return Status::COMPLETE;
          }
          if (buffer.ifNext(ZString("\r\n"))) {
             last = false;
             return Status::COMPLETE;
          }
          throw coreutils::Exception("IMFBoundary: malformed boundary line - expected CRLF or trailing --.");

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

   bool IMFBoundary::isLast() {
      return last;
   }

}