//Required to fix compile errors with xdelta3
#define SIZEOF_SIZE_T 4
#define static_assert(e,m) /* do nothing */
#define XD3_ENCODER 0
#define XD3_USE_LARGESIZET 0
typedef unsigned int usize_t;
typedef unsigned long long xoff_t;
//Include xdelta3
#include "../lib/xdelta3/xdelta3.c"

//Include other libraries
#include <errno.h>
#include <stdbool.h>
#include <unistd.h>

//Include our own files
#include "errorAndExit.h"
#include "rateLimiter.h"
#include "xdelta3.h"

//Various variables for Xdelta3
xd3_stream stream;
xd3_config config;
xd3_source source;
//The previous version of the file we want to extract
FILE* srcFile;
//Total number of bytes written to output
unsigned long totalOut = 0UL;

/** Initializes xdelta3 with the given previous file */
void xdelta3Init(char* prevFile) {
  srcFile = fopen(prevFile, "rb");
  if (srcFile == NULL) {
    fprintf(stderr, "Could not open previous file %s for reading during xdelta3: %s\n", prevFile, strerror(errno));
    errorAndExit();
  }

  xd3_init_config(&config, XD3_ADLER32);
  config.winsize = XD3_ALLOCSIZE;
  xd3_config_stream(&stream, &config);
  //Set source (= old file from previous release)
  source.blksize = XD3_ALLOCSIZE;
  source.curblk = malloc(source.blksize);
  if (source.curblk == NULL) {
    fprintf(stderr, "ERROR: Could not allocate source.blksize in VCDIFF.\n");
    errorAndExit();
  }

  fseek(srcFile, 0, SEEK_SET);
  source.onblk = fread((void*)source.curblk, 1, source.blksize, srcFile);
  source.curblkno = 0;
  xd3_set_source(&stream, &source);
  //Set input (= xdelta file from current release)
  xd3_set_flags(&stream, XD3_FLUSH | stream.flags);
}


/** Supplies the given input buffer to xdelta3 and undiffs the data. */
void xdelta3AddInput(unsigned char* inputBuffer, unsigned int inputLength, bool isLastPart, FILE* targetFile) {
  xd3_avail_input(&stream, inputBuffer, inputLength);

  int returnValue;

process:
  returnValue = xd3_decode_input(&stream);
  switch (returnValue) {
    case XD3_INPUT: {
      //fprintf(stderr, "XD3_INPUT\n");
      break;
    }
    case XD3_OUTPUT: {
      //fprintf(stderr, "XD3_OUTPUT\n");
      totalOut += stream.avail_out;
      consumeCapacity(stream.avail_out);
      if (targetFile) {
        fwrite(stream.next_out, 1, stream.avail_out, targetFile);
      } else {
        write(1, stream.next_out, stream.avail_out);
      }
      xd3_consume_output(&stream);
      goto process;
    }
    case XD3_GETSRCBLK: {
      //fprintf(stderr, "XD3_GETSRCBLK\n");
      fseek(srcFile, source.blksize * source.getblkno, SEEK_SET);
      source.onblk = fread((void*)source.curblk, 1, source.blksize, srcFile);
      source.curblkno = source.getblkno;
      goto process;
    }
    case XD3_GOTHEADER: {
      //fprintf(stderr, "XD3_GOTHEADER\n");
      goto process;
    }
    case XD3_WINSTART: {
      //fprintf(stderr, "XD3_WINSTART\n");
      goto process;
    }
    case XD3_WINFINISH: {
      //fprintf(stderr, "XD3_WINFINISH\n");
      goto process;
    }
    default: {
      fprintf(stderr, "ERROR: !!! INVALID %s %d !!!\n", stream.msg, returnValue);
      errorAndExit();
    }
  }

  //If we are done, free up memory
  if (isLastPart) {
    free((void*)source.curblk);
    xd3_close_stream(&stream);
    xd3_free_stream(&stream);
    fclose(srcFile);
  }
}