#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/mman.h>
#include <sys/stat.h>

#include "ldm.h"

#define BUF_SIZE 16*1024  // Block size
#define LDM_HEADER_SIZE 8

/*
static size_t compress_file_mmap(FILE *in, FILE *out, size_t *size_in,
                                 size_t *size_out) {
  char *src, *dst;
  struct stat statbuf;

  if (fstat(in, &statbuf) < 0) {
    printf("fstat error\n");
    return 1;
  }


  return 0;
}
*/

static size_t compress_file(FILE *in, FILE *out, size_t *size_in,
                            size_t *size_out) {
  char *src, *buf = NULL;
  size_t r = 1;
  size_t size, n, k, count_in = 0, count_out = 0, offset, frame_size = 0;

  src = malloc(BUF_SIZE);
  if (!src) {
    printf("Not enough memory\n");
    goto cleanup;
  }

  size = BUF_SIZE + LDM_HEADER_SIZE;
  buf = malloc(size);
  if (!buf) {
    printf("Not enough memory\n");
    goto cleanup;
  }

  for (;;) {
    k = fread(src, 1, BUF_SIZE, in);
    if (k == 0)
      break;
    count_in += k;

    n = LDM_compress(src, buf, k, BUF_SIZE);

    // n = k;
    // offset += n;
    offset = n;
    count_out += n;

    k = fwrite(buf, 1, offset, out);
    if (k < offset) {
      if (ferror(out))
        printf("Write failed\n");
      else
        printf("Short write\n");
      goto cleanup;
    }

  }
  *size_in = count_in;
  *size_out = count_out;
  r = 0;
 cleanup:
  free(src);
  free(buf);
  return r;
}

static size_t decompress_file(FILE *in, FILE *out) {
  void *src = malloc(BUF_SIZE);
  void *dst = NULL;
  size_t dst_capacity = BUF_SIZE;
  size_t ret = 1;
  size_t bytes_written = 0;

  if (!src) {
    perror("decompress_file(src)");
    goto cleanup;
  }

  while (ret != 0) {
    /* Load more input */
    size_t src_size = fread(src, 1, BUF_SIZE, in);
    void *src_ptr = src;
    void *src_end = src_ptr + src_size;
    if (src_size == 0 || ferror(in)) {
      printf("(TODO): Decompress: not enough input or error reading file\n");
      //TODO
      ret = 0;
      goto cleanup;
    }

    /* Allocate destination buffer if it hasn't been allocated already */
    if (!dst) {
      dst = malloc(dst_capacity);
      if (!dst) {
        perror("decompress_file(dst)");
        goto cleanup;
      }
    }

    /* Decompress:
     * Continue while there is more input to read.
     */
    while (src_ptr != src_end && ret != 0) {
      // size_t dst_size = src_size;
      size_t dst_size = LDM_decompress(src, dst, src_size, dst_capacity);
      size_t written = fwrite(dst, 1, dst_size, out);
//      printf("Writing %zu bytes\n", dst_size);
      bytes_written += dst_size;
      if (written != dst_size) {
        printf("Decompress: Failed to write to file\n");
        goto cleanup;
      }
      src_ptr += src_size;
      src_size = src_end - src_ptr;
    }

    /* Update input */

  }

  printf("Wrote %zu bytes\n", bytes_written);

 cleanup:
  free(src);
  free(dst);

  return ret;
}

static int compare(FILE *fp0, FILE *fp1) {
  int result = 0;
  while (result == 0) {
    char b0[1024];
    char b1[1024];
    const size_t r0 = fread(b0, 1, sizeof(b0), fp0);
    const size_t r1 = fread(b1, 1, sizeof(b1), fp1);

    result = (int)r0 - (int)r1;

    if (0 == r0 || 0 == r1) {
      break;
    }
    if (0 == result) {
      result = memcmp(b0, b1, r0);
    }
  }
  return result;
}

int main(int argc, char *argv[]) {
  char inpFilename[256] = { 0 };
  char ldmFilename[256] = { 0 };
  char decFilename[256] = { 0 };

  if (argc < 2) {
    printf("Please specify input filename\n");
    return 0;
  }
  snprintf(inpFilename, 256, "%s", argv[1]);
  snprintf(ldmFilename, 256, "%s.ldm", argv[1]);
  snprintf(decFilename, 256, "%s.ldm.dec", argv[1]);

 	printf("inp = [%s]\n", inpFilename);
	printf("ldm = [%s]\n", ldmFilename);
	printf("dec = [%s]\n", decFilename);

  /* compress */
  {
    FILE *inpFp = fopen(inpFilename, "rb");
    FILE *outFp = fopen(ldmFilename, "wb");
    size_t sizeIn = 0;
    size_t sizeOut = 0;
    size_t ret;
		printf("compress : %s -> %s\n", inpFilename, ldmFilename);
		ret = compress_file(inpFp, outFp, &sizeIn, &sizeOut);
		if (ret) {
			printf("compress : failed with code %zu\n", ret);
			return ret;
		}
		printf("%s: %zu → %zu bytes, %.1f%%\n",
			inpFilename, sizeIn, sizeOut,
			(double)sizeOut / sizeIn * 100);
		printf("compress : done\n");

		fclose(outFp);
		fclose(inpFp);
  }

	/* decompress */
	{
    FILE *inpFp = fopen(ldmFilename, "rb");
		FILE *outFp = fopen(decFilename, "wb");
		size_t ret;

		printf("decompress : %s -> %s\n", ldmFilename, decFilename);
		ret = decompress_file(inpFp, outFp);
		if (ret) {
			printf("decompress : failed with code %zu\n", ret);
			return ret;
		}
		printf("decompress : done\n");

		fclose(outFp);
		fclose(inpFp);
	}

	/* verify */
	{
    FILE *inpFp = fopen(inpFilename, "rb");
		FILE *decFp = fopen(decFilename, "rb");

		printf("verify : %s <-> %s\n", inpFilename, decFilename);
		const int cmp = compare(inpFp, decFp);
		if(0 == cmp) {
			printf("verify : OK\n");
		} else {
			printf("verify : NG\n");
		}

		fclose(decFp);
		fclose(inpFp);
	}

  return 0;
}