#include <assert.h>
#include <fx/compress/compressor.h>
#include <fx/compress/zstd.h>
#include <fx/core/ringbuffer.h>
#include <stdio.h>
#include <string.h>

#define BUF_SIZE 32

int refill_input_buffer(FILE *fp, fx_ringbuffer *dest)
{
	while (1) {
		void *buf;
		size_t capacity;
		fx_status status
			= fx_ringbuffer_open_write_buffer(dest, &buf, &capacity);
		if (status == FX_ERR_NO_SPACE) {
			break;
		}

		if (!FX_OK(status)) {
			return -1;
		}

		size_t r = fread(buf, 1, capacity, fp);

		fx_ringbuffer_close_write_buffer(dest, &buf, r);

		if (r == 0) {
			return ferror(fp) ? -1 : 0;
		}

		if (r < capacity) {
			break;
		}
	}

	return 0;
}

int flush_output_buffer(FILE *fp, fx_ringbuffer *src)
{
	while (1) {
		const void *buf;
		size_t capacity;
		fx_status status
			= fx_ringbuffer_open_read_buffer(src, &buf, &capacity);
		if (status == FX_ERR_NO_DATA) {
			break;
		}

		if (!FX_OK(status)) {
			return -1;
		}

		size_t w = fwrite(buf, 1, capacity, fp);

		fx_ringbuffer_close_read_buffer(src, &buf, w);

		if (w < capacity) {
			return -1;
		}
	}

	return 0;
}

int main(int argc, const char **argv)
{
	if (argc < 4) {
		fprintf(stderr, "usage: %s <C/D> <inpath> <outpath>\n", argv[0]);
		return -1;
	}

	fx_compressor_mode mode;
	if (!strcmp(argv[1], "C")) {
		mode = FX_COMPRESSOR_MODE_COMPRESS;
	} else if (!strcmp(argv[1], "D")) {
		mode = FX_COMPRESSOR_MODE_DECOMPRESS;
	} else {
		fprintf(stderr, "invalid mode %s\n", argv[1]);
		return -1;
	}

	FILE *in_fp = fopen(argv[2], "rb");
	if (!in_fp) {
		fprintf(stderr, "cannot open input file %s\n", argv[2]);
		return -1;
	}

	FILE *out_fp = fopen(argv[3], "wb");
	if (!out_fp) {
		fclose(in_fp);
		fprintf(stderr, "cannot open output file %s\n", argv[3]);
		return -1;
	}

	fx_status status = FX_SUCCESS;
	fx_type compressor_type = FX_TYPE_ZSTD_COMPRESSOR;
	fx_compressor *compressor = fx_object_create(compressor_type);

	size_t inbuf_size, outbuf_size;
	fx_compressor_get_buffer_size(
		compressor_type, mode, &inbuf_size, &outbuf_size);

	fx_ringbuffer *in = fx_ringbuffer_create(inbuf_size);
	fx_ringbuffer *out = fx_ringbuffer_create(outbuf_size);

	if (!in || !out) {
		fprintf(stderr, "memory allocation failure");
		return -1;
	}

	fx_compressor_set_buffer(compressor, in, out);
	fx_compressor_set_mode(compressor, mode);

	int ret = 0;
	while (1) {
		ret = refill_input_buffer(in_fp, in);
		if (ret != 0) {
			fprintf(stderr, "read error\n");
			break;
		}

		if (!fx_ringbuffer_available_data_remaining(in)) {
			break;
		}

		status = fx_compressor_step(compressor);

		if (status == FX_ERR_NO_DATA) {
			break;
		} else if (status == FX_ERR_NO_SPACE) {
			ret = flush_output_buffer(out_fp, out);
			if (ret != 0) {
				fprintf(stderr, "write error\n");
				break;
			}
		} else if (!FX_OK(status)) {
			ret = -1;
			break;
		}
	}

	ret = flush_output_buffer(out_fp, out);
	if (ret != 0) {
		fprintf(stderr, "write error\n");
		return -1;
	}

	if (mode == FX_COMPRESSOR_MODE_COMPRESS) {
		while (!fx_compressor_eof(compressor)) {
			status = fx_compressor_end(compressor);
			if (!FX_OK(status)) {
				fprintf(stderr,
				        "compression finalisation error\n");
				return -1;
			}

			if (!fx_ringbuffer_available_data_remaining(out)) {
				break;
			}

			ret = flush_output_buffer(out_fp, out);
			if (ret != 0) {
				fprintf(stderr, "write error\n");
				return -1;
			}
		}
	}

	printf("Done\n");

	fx_compressor_unref(compressor);

	fclose(in_fp);
	fclose(out_fp);

	fx_ringbuffer_unref(in);
	fx_ringbuffer_unref(out);

	return ret;
}