/*
** Common functionality for tests.
**/

#ifndef UPB_TEST_UTIL_H_
#define UPB_TEST_UTIL_H_

#include <stdio.h>
#include <math.h>
#include "tests/upb_test.h"
#include "upb/sink.h"

#include "upb/port_def.inc"

#ifdef __cplusplus

upb_bufhandle global_handle;

/* A convenience class for parser tests.  Provides some useful features:
 *
 *   - can support multiple calls to parse, to test the parser's handling
 *     of buffer seams.
 *
 *   - can output verbose output about each parse call when requested, for
 *     ease of debugging.
 *
 *   - can pass NULL for skipped regions of the input if requested.
 *
 *   - allocates and passes a separate buffer for each parsed region, to
 *     ensure that the parser is not erroneously overreading its buffer.
 */
class VerboseParserEnvironment {
 public:
  /* Pass verbose=true to print detailed diagnostics to stderr. */
  VerboseParserEnvironment(bool verbose) : verbose_(verbose) {}

  void Reset(const char *buf, size_t len, bool may_skip, bool expect_error) {
    buf_ = buf;
    len_ = len;
    ofs_ = 0;
    expect_error_ = expect_error;
    end_ok_set_ = false;
    skip_until_ = may_skip ? 0 : -1;
    skipped_with_null_ = false;
  }

  /* The user should call a series of:
   *
   * Reset(buf, len, may_skip);
   * Start()
   * ParseBuffer(X);
   * ParseBuffer(Y);
   * // Repeat ParseBuffer as desired, but last call should pass -1.
   * ParseBuffer(-1);
   * End();
   */


  bool Start() {
    if (verbose_) {
      fprintf(stderr, "Calling start()\n");
    }
    return sink_.Start(len_, &subc_);
  }

  bool End() {
    if (verbose_) {
      fprintf(stderr, "Calling end()\n");
    }
    end_ok_ = sink_.End();
    end_ok_set_ = true;

    return end_ok_;
  }

  bool CheckConsistency() {
    /* If we called end (which we should only do when previous bytes are fully
     * accepted), then end() should return true iff there were no errors. */
    if (end_ok_set_ && end_ok_ != status_.ok()) {
      fprintf(stderr, "End() status and saw_error didn't match.\n");
      return false;
    }

    if (expect_error_ && status_.ok()) {
      fprintf(stderr, "Expected error but saw none.\n");
      return false;
    }

    if (!status_.ok()) {
      if (expect_error_ && verbose_) {
        fprintf(stderr, "Encountered error, as expected: %s",
                status_.error_message());
      } else if (!expect_error_) {
        fprintf(stderr, "Encountered unexpected error: %s",
                status_.error_message());
        return false;
      }
    }

    return true;
  }

  bool ParseBuffer(int bytes) {
    if (bytes < 0) {
      bytes = len_ - ofs_;
    }

    ASSERT((size_t)bytes <= (len_ - ofs_));

    /* Copy buffer into a separate, temporary buffer.
     * This is necessary to verify that the parser is not erroneously
     * reading outside the specified bounds. */
    char *buf2 = NULL;

    if ((int)(ofs_ + bytes) <= skip_until_) {
      skipped_with_null_ = true;
    } else {
      buf2 = (char*)malloc(bytes);
      UPB_ASSERT(buf2);
      memcpy(buf2, buf_ + ofs_, bytes);
    }

    if (buf2 == NULL && bytes == 0) {
      /* Decoders dont' support buf=NULL, bytes=0. */
      return true;
    }

    if (verbose_) {
      fprintf(stderr, "Calling parse(%u) for bytes %u-%u of the input\n",
              (unsigned)bytes, (unsigned)ofs_, (unsigned)(ofs_ + bytes));
    }

    int parsed = sink_.PutBuffer(subc_, buf2, bytes, &global_handle);
    free(buf2);

    if (verbose_) {
      if (parsed == bytes) {
        fprintf(stderr,
                "parse(%u) = %u, complete byte count indicates success\n",
                (unsigned)bytes, (unsigned)bytes);
      } else if (parsed > bytes) {
        fprintf(stderr,
                "parse(%u) = %u, long byte count indicates success and skip "
                "of the next %u bytes\n",
                (unsigned)bytes, (unsigned)parsed, (unsigned)(parsed - bytes));
      } else {
        fprintf(stderr,
                "parse(%u) = %u, short byte count indicates failure; "
                "last %u bytes were not consumed\n",
                (unsigned)bytes, (unsigned)parsed, (unsigned)(bytes - parsed));
      }
    }

    if (!status_.ok()) {
      return false;
    }

    if (parsed > bytes && skip_until_ >= 0) {
      skip_until_ = ofs_ + parsed;
    }

    ofs_ += UPB_MIN(parsed, bytes);

    return true;
  }

  void ResetBytesSink(upb::BytesSink sink) {
    sink_ = sink;
  }

  size_t ofs() { return ofs_; }

  bool SkippedWithNull() { return skipped_with_null_; }

  upb::Arena* arena() { return &arena_; }
  upb::Status* status() { return &status_; }

 private:
  upb::Arena arena_;
  upb::Status status_;
  upb::BytesSink sink_;
  const char* buf_;
  size_t len_;
  bool verbose_;
  size_t ofs_;
  void *subc_;
  bool expect_error_;
  bool end_ok_;
  bool end_ok_set_;

  /* When our parse call returns a value greater than the number of bytes
   * we passed in, the decoder is indicating to us that the next N bytes
   * in the stream are not needed and can be skipped.  The user is allowed
   * to pass a NULL buffer for those N bytes.
   *
   * skip_until_ is initially set to 0 if we should do this NULL-buffer
   * skipping or -1 if we should not.  If we are open to doing NULL-buffer
   * skipping and we get an opportunity to do it, we set skip_until to the
   * stream offset where we can skip until.  The user can then test whether
   * this happened by testing SkippedWithNull(). */
  int skip_until_;
  bool skipped_with_null_;
};

#endif  /* __cplusplus */

UPB_INLINE char *upb_readfile(const char *filename, size_t *len) {
  long size;
  char *buf;
  FILE *f = fopen(filename, "rb");
  if(!f) return NULL;
  if(fseek(f, 0, SEEK_END) != 0) goto error;
  size = ftell(f);
  if(size < 0) goto error;
  if(fseek(f, 0, SEEK_SET) != 0) goto error;
  buf = (char*)malloc(size + 1);
  if(size && fread(buf, size, 1, f) != 1) goto error;
  fclose(f);
  if (len) *len = size;
  buf[size] = '\0';
  return buf;

error:
  fclose(f);
  return NULL;
}

#include "upb/port_undef.inc"

#endif /* UPB_TEST_UTIL_H_ */