#include <keraforge.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <lzma.h>


int kf_exists(char *filename)
{
	FILE *fp = fopen(filename, "r");
	bool opened = fp != NULL;
	if (opened)
		fclose(fp);
	return opened;
}

u8 *kf_readbin(char *filename, size_t *plen)
{
	FILE *fp = fopen(filename, "rb");
	if (!fp)
		return NULL;

	*plen = 0;
	fseek(fp, 0, SEEK_END);
	*plen = ftell(fp);
	fseek(fp, 0, SEEK_SET);
	if (*plen == 0)
	{
		fclose(fp);
		return NULL;
	}

	u8 *data = malloc(*plen);
	(void)fread(data, 1, *plen, fp);
	fclose(fp);

	return data;
}

int kf_writebin(char *filename, u8 *data, size_t len)
{
	FILE *fp = fopen(filename, "wb");
	if (!fp)
		return 0;

	size_t n = fwrite(data, 1, len, fp);
	fclose(fp);

	if (n != len)
		return 0;

	return 1;
}

static
int _kf_compress(lzma_stream *s, FILE *ifp, FILE *ofp)
{
	lzma_action a = LZMA_RUN;
	u8 inbuf[BUFSIZ], outbuf[BUFSIZ];

	s->next_in = NULL;
	s->avail_in = 0;
	s->next_out = outbuf;
	s->avail_out = sizeof(outbuf);

	for (;;)
	{
		if (s->avail_in == 0 && !feof(ifp))
		{
			s->next_in = inbuf;
			s->avail_in = fread(inbuf, 1, sizeof(inbuf), ifp);

			if (ferror(ifp))
			{
				KF_THROW("read error: %s", strerror(errno));
				return 0; /* unreachable */
			}

			if (feof(ifp))
				a = LZMA_FINISH;
		}

		lzma_ret r = lzma_code(s, a);

		if (s->avail_out == 0 || r == LZMA_STREAM_END)
		{
			size_t nwrote = sizeof(outbuf) - s->avail_out;

			if (fwrite(outbuf, 1, nwrote, ofp) != nwrote)
			{
				KF_THROW("write error: %s", strerror(errno));
				return 0; /* unreachable */
			}

			s->next_out = outbuf;
			s->avail_out = sizeof(outbuf);
		}

		if (r != LZMA_OK)
		{
			if (r == LZMA_STREAM_END)
				return 1;

			KF_THROW("lzma compression error: code=%d", r);
			return 0; /* unreachable */
		}
	}

	KF_UNREACHABLE("broke out of for(;;) loop");
	return 0; /* unreachable */
}

int kf_compress(char *infile, char *outfile)
{
	FILE *ifp = fopen(infile, "r");
	if (!ifp)
	{
		KF_THROW("failed to open input file: %s", infile);
		return 0; /* unreachable */
	}
	FILE *ofp = fopen(outfile, "w");
	if (!ofp)
	{
		fclose(ifp);
		KF_THROW("failed to open output file: %s", outfile);
		return 0; /* unreachable */
	}

	lzma_stream s = LZMA_STREAM_INIT;
	lzma_ret r = lzma_easy_encoder(&s, LZMA_PRESET_DEFAULT, LZMA_CHECK_CRC64);
	if (r != LZMA_OK)
	{
		KF_THROW("failed to initialize lzma encoder: code=%d\n", r);
		return 0; /* unreachable */
	}

	int res = _kf_compress(&s, ifp, ofp);

	lzma_end(&s);
	fclose(ifp);
	fclose(ofp);

	return res;
}

int kf_decompress(char *infile, char *outfile)
{
	FILE *ifp = fopen(infile, "r");
	if (!ifp)
	{
		KF_THROW("failed to open input file: %s", infile);
		return 0; /* unreachable */
	}
	FILE *ofp = fopen(outfile, "w");
	if (!ofp)
	{
		fclose(ifp);
		KF_THROW("failed to open output file: %s", outfile);
		return 0; /* unreachable */
	}

	lzma_stream s = LZMA_STREAM_INIT;
	lzma_ret r = lzma_stream_decoder(&s, UINT64_MAX, LZMA_CONCATENATED);
	if (r != LZMA_OK)
	{
		KF_THROW("failed to initialize lzma decoder: code=%d\n", r);
		return 0; /* unreachable */
	}

	int res = _kf_compress(&s, ifp, ofp);

	lzma_end(&s);
	fclose(ifp);
	fclose(ofp);

	return res;
}