#include <unistd.h>
#include <sys/mman.h>

#include <zlib.h>
#include <lzma.h>
#include <lz4.h>
#include <lz4frame.h>
#include <lz4hc.h>
#include <bzlib.h>

#include "magiskboot.h"
#include "logging.h"
#include "utils.h"

#define windowBits 15
#define ZLIB_GZIP 16
#define memLevel 8
#define CHUNK 0x40000

#define LZ4_HEADER_SIZE 19
#define LZ4_FOOTER_SIZE 4
#define LZ4_LEGACY_BLOCKSIZE  0x800000

// Mode: 0 = decode; 1 = encode
size_t gzip(int mode, int fd, const void *buf, size_t size) {
	size_t ret = 0, flush, have, pos = 0, total = 0;
	z_stream strm;
	unsigned char out[CHUNK];

	strm.zalloc = Z_NULL;
	strm.zfree = Z_NULL;
	strm.opaque = Z_NULL;

	switch(mode) {
		case 0:
			ret = inflateInit2(&strm, windowBits | ZLIB_GZIP);
			break;
		case 1:
			ret = deflateInit2(&strm, 9, Z_DEFLATED, windowBits | ZLIB_GZIP, memLevel, Z_DEFAULT_STRATEGY);
			break;
	}

	if (ret != Z_OK)
		LOGE("Unable to init zlib stream\n");

	do {
		strm.next_in = (void *) buf + pos;
		if (pos + CHUNK >= size) {
			strm.avail_in = size - pos;
			flush = Z_FINISH;
		} else {
			strm.avail_in = CHUNK;
			flush = Z_NO_FLUSH;
		}
		pos += strm.avail_in;

		do {
			strm.avail_out = CHUNK;
			strm.next_out = out;
			switch(mode) {
				case 0:
					ret = inflate(&strm, flush);
					break;
				case 1:
					ret = deflate(&strm, flush);
					break;
			}
			if (ret == Z_STREAM_ERROR)
				LOGE("Error when running gzip\n");

			have = CHUNK - strm.avail_out;
			total += xwrite(fd, out, have);

		} while (strm.avail_out == 0);

	} while(pos < size);

	switch(mode) {
		case 0:
			inflateEnd(&strm);
			break;
		case 1:
			deflateEnd(&strm);
			break;
	}
	return total;
}


// Mode: 0 = decode xz/lzma; 1 = encode xz; 2 = encode lzma
size_t lzma(int mode, int fd, const void *buf, size_t size) {
	size_t have, pos = 0, total = 0;
	lzma_ret ret = 0;
	lzma_stream strm = LZMA_STREAM_INIT;
	lzma_options_lzma opt;
	lzma_action action;
	unsigned char out[BUFSIZ];

	// Initialize preset
	lzma_lzma_preset(&opt, 9);
	lzma_filter filters[] = {
		{ .id = LZMA_FILTER_LZMA2, .options = &opt },
		{ .id = LZMA_VLI_UNKNOWN, .options = NULL },
	};

	switch(mode) {
		case 0:
			ret = lzma_auto_decoder(&strm, UINT64_MAX, 0);
			break;
		case 1:
			ret = lzma_stream_encoder(&strm, filters, LZMA_CHECK_CRC32);
			break;
		case 2:
			ret = lzma_alone_encoder(&strm, &opt);
			break;
	}


	if (ret != LZMA_OK)
		LOGE("Unable to init lzma stream\n");

	do {
		strm.next_in = buf + pos;
		if (pos + BUFSIZ >= size) {
			strm.avail_in = size - pos;
			action = LZMA_FINISH;
		} else {
			strm.avail_in = BUFSIZ;
			action = LZMA_RUN;
		}
		pos += strm.avail_in;

		do {
			strm.avail_out = BUFSIZ;
			strm.next_out = out;
			ret = lzma_code(&strm, action);
			have = BUFSIZ - strm.avail_out;
			total += xwrite(fd, out, have);
		} while (strm.avail_out == 0 && ret == LZMA_OK);

		if (ret != LZMA_OK && ret != LZMA_STREAM_END)
			LOGE("LZMA error %d!\n", ret);

	} while (pos < size);

	lzma_end(&strm);
	return total;
}

// Mode: 0 = decode; 1 = encode
size_t lz4(int mode, int fd, const void *buf, size_t size) {
	LZ4F_decompressionContext_t dctx;
	LZ4F_compressionContext_t cctx;
	LZ4F_frameInfo_t info;

	size_t blockSize, outCapacity, avail_in, ret = 0, pos = 0, total = 0;
	size_t have, read;
	void *out = NULL;

	// Initialize context
	switch(mode) {
		case 0:
			ret = LZ4F_createDecompressionContext(&dctx, LZ4F_VERSION);
			break;
		case 1:
			ret = LZ4F_createCompressionContext(&cctx, LZ4F_VERSION);
			break;
	}

	if (LZ4F_isError(ret))
		LOGE("Context creation error: %s\n", LZ4F_getErrorName(ret));

	// Allocate out buffer
	blockSize = 1 << 22;
	switch(mode) {
		case 0:
			// Read header
			read = blockSize;
			ret = LZ4F_getFrameInfo(dctx, &info, buf, &read);
			if (LZ4F_isError(ret))
				LOGE("LZ4F_getFrameInfo error: %s\n", LZ4F_getErrorName(ret));
			switch (info.blockSizeID) {
				case LZ4F_default:
				case LZ4F_max64KB:  outCapacity = 1 << 16; break;
				case LZ4F_max256KB: outCapacity = 1 << 18; break;
				case LZ4F_max1MB:   outCapacity = 1 << 20; break;
				case LZ4F_max4MB:   outCapacity = 1 << 22; break;
				default:
					LOGE("Impossible unless more block sizes are allowed\n");
			}
			pos += read;
			break;
		case 1:
			outCapacity = LZ4F_compressFrameBound(blockSize, NULL);
			break;
	}

	out = xmalloc(outCapacity);

	// Write header
	if (mode == 1) {
		LZ4F_preferences_t prefs;
		memset(&prefs, 0, sizeof(prefs));
		prefs.autoFlush = 1;
		prefs.compressionLevel = 9;
		prefs.frameInfo.blockMode = 1;
		prefs.frameInfo.blockSizeID = 7;
		prefs.frameInfo.contentChecksumFlag = 1;
		have = ret = LZ4F_compressBegin(cctx, out, size, &prefs);
		if (LZ4F_isError(ret))
			LOGE("Failed to start compression: error %s\n", LZ4F_getErrorName(ret));
		total += xwrite(fd, out, have);
	}

	do {
		if (pos + blockSize >= size) {
			avail_in = size - pos;
		} else {
			avail_in = blockSize;
		}

		do {
			switch(mode) {
				case 0:
					have = outCapacity;
					read = avail_in;
					ret = LZ4F_decompress(dctx, out, &have, buf + pos, &read, NULL);
					break;
				case 1:
					read = avail_in;
					have = ret = LZ4F_compressUpdate(cctx, out, outCapacity, buf + pos, avail_in, NULL);
					break;
			}
			if (LZ4F_isError(ret))
				LOGE("LZ4 coding error: %s\n", LZ4F_getErrorName(ret));

			total += xwrite(fd, out, have);
			// Update status
			pos += read;
			avail_in -= read;
		} while(avail_in != 0 && ret != 0);

	} while(pos < size && ret != 0);

	switch(mode) {
		case 0:
			LZ4F_freeDecompressionContext(dctx);
			break;
		case 1:
			have = ret = LZ4F_compressEnd(cctx, out, outCapacity, NULL);
			if (LZ4F_isError(ret))
				LOGE("Failed to end compression: error %s\n", LZ4F_getErrorName(ret));

			total += xwrite(fd, out, have);

			LZ4F_freeCompressionContext(cctx);
			break;
	}

	free(out);
	return total;
}

// Mode: 0 = decode; 1 = encode
size_t bzip2(int mode, int fd, const void* buf, size_t size) {
	size_t ret = 0, action, have, pos = 0, total = 0;
	bz_stream strm;
	char out[CHUNK];

	strm.bzalloc = NULL;
	strm.bzfree = NULL;
	strm.opaque = NULL;

	switch(mode) {
		case 0:
			ret = BZ2_bzDecompressInit(&strm, 0, 0);
			break;
		case 1:
			ret = BZ2_bzCompressInit(&strm, 9, 0, 0);
			break;
	}

	if (ret != BZ_OK)
		LOGE("Unable to init bzlib stream\n");

	do {
		strm.next_in = (char *) buf + pos;
		if (pos + CHUNK >= size) {
			strm.avail_in = size - pos;
			action = BZ_FINISH;
		} else {
			strm.avail_in = CHUNK;
			action = BZ_RUN;
		}
		pos += strm.avail_in;

		do {
			strm.avail_out = CHUNK;
			strm.next_out = out;
			switch(mode) {
				case 0:
					ret = BZ2_bzDecompress(&strm);
					break;
				case 1:
					ret = BZ2_bzCompress(&strm, action);
					break;
			}

			have = CHUNK - strm.avail_out;
			total += xwrite(fd, out, have);

		} while (strm.avail_out == 0);

	} while(pos < size);

	switch(mode) {
		case 0:
			BZ2_bzDecompressEnd(&strm);
			break;
		case 1:
			BZ2_bzCompressEnd(&strm);
			break;
	}
	return total;
}

// Mode: 0 = decode; 1 = encode
size_t lz4_legacy(int mode, int fd, const void* buf, size_t size) {
	size_t pos = 0;
	int have;
	char *out;
	unsigned block_size, insize, total = 0;

	switch(mode) {
		case 0:
			out = xmalloc(LZ4_LEGACY_BLOCKSIZE);
			// Skip magic
			pos += 4;
			break;
		case 1:
			out = xmalloc(LZ4_COMPRESSBOUND(LZ4_LEGACY_BLOCKSIZE));
			// Write magic
			total += xwrite(fd, "\x02\x21\x4c\x18", 4);
			break;
	}

	do {
		switch(mode) {
			case 0:
				// Read block size
				block_size = *(unsigned *)(buf + pos);
				pos += 4;
				if (block_size > LZ4_COMPRESSBOUND(LZ4_LEGACY_BLOCKSIZE))
					goto done;
				have = LZ4_decompress_safe(buf + pos, out, block_size, LZ4_LEGACY_BLOCKSIZE);
				if (have < 0)
					LOGE("Cannot decode lz4_legacy block\n");
				pos += block_size;
				break;
			case 1:
				if (pos + LZ4_LEGACY_BLOCKSIZE >= size)
					insize = size - pos;
				else
					insize = LZ4_LEGACY_BLOCKSIZE;
				have = LZ4_compress_HC(buf + pos, out, insize, LZ4_COMPRESSBOUND(LZ4_LEGACY_BLOCKSIZE), 9);
				if (have == 0)
					LOGE("lz4_legacy compression error\n");
				pos += insize;
				// Write block size
				total += xwrite(fd, &have, sizeof(have));
				break;
		}
		// Write main data
		total += xwrite(fd, out, have);
	} while(pos < size);

done:
	if (mode == 1) {
		// Append original size to output
		unsigned uncomp = size;
		xwrite(fd, &uncomp, sizeof(uncomp));
	}
	free(out);
	return total;
}

long long decomp(file_t type, int to, const void *from, size_t size) {
	switch (type) {
		case GZIP:
			return gzip(0, to, from, size);
		case XZ:
			return lzma(0, to, from, size);
		case LZMA:
			return lzma(0, to, from, size);
		case BZIP2:
			return bzip2(0, to, from, size);
		case LZ4:
			return lz4(0, to, from, size);
		case LZ4_LEGACY:
			return lz4_legacy(0, to, from, size);
		default:
			// Unsupported
			return -1;
	}
}

// Output will be to.ext
long long comp(file_t type, int to, const void *from, size_t size) {
	switch (type) {
		case GZIP:
			return gzip(1, to, from, size);
		case XZ:
			return lzma(1, to, from, size);
		case LZMA:
			return lzma(2, to, from, size);
		case BZIP2:
			return bzip2(1, to, from, size);
		case LZ4:
			return lz4(1, to, from, size);
		case LZ4_LEGACY:
			return lz4_legacy(1, to, from, size);
		default:
			// Unsupported
			return -1;
	}
}

/*
 * Below are utility functions for commandline
 */

void decomp_file(char *from, const char *to) {
	int ok = 1;
	void *file;
	size_t size;
	mmap_ro(from, &file, &size);
	file_t type = check_type(file);
	char *ext;
	ext = strrchr(from, '.');
	if (ext == NULL)
		LOGE("Bad filename extention\n");

	// File type and extension should match
	switch (type) {
		case GZIP:
			if (strcmp(ext, ".gz") != 0)
				ok = 0;
			break;
		case XZ:
			if (strcmp(ext, ".xz") != 0)
				ok = 0;
			break;
		case LZMA:
			if (strcmp(ext, ".lzma") != 0)
				ok = 0;
			break;
		case BZIP2:
			if (strcmp(ext, ".bz2") != 0)
				ok = 0;
			break;
		case LZ4_LEGACY:
		case LZ4:
			if (strcmp(ext, ".lz4") != 0)
				ok = 0;
			break;
		default:
			LOGE("Provided file \'%s\' is not a supported archive format\n", from);
	}
	if (ok) {
		// If all match, strip out the suffix
		if (!to) {
			*ext = '\0';
			to = from;
		}
		int fd = open_new(to);
		fprintf(stderr, "Decompressing to [%s]\n\n", to);
		decomp(type, fd, file, size);
		close(fd);
		if (to == from) {
			*ext = '.';
			unlink(from);
		}
	} else {
		LOGE("Bad filename extention \'%s\'\n", ext);
	}
	munmap(file, size);
}

void comp_file(const char *method, const char *from, const char *to) {
	file_t type;
	char *ext, dest[PATH_MAX];
	if (strcmp(method, "gzip") == 0) {
		type = GZIP;
		ext = "gz";
	} else if (strcmp(method, "xz") == 0) {
		type = XZ;
		ext = "xz";
	} else if (strcmp(method, "lzma") == 0) {
		type = LZMA;
		ext = "lzma";
	} else if (strcmp(method, "lz4") == 0) {
		type = LZ4;
		ext = "lz4";
	} else if (strcmp(method, "lz4_legacy") == 0) {
		type = LZ4_LEGACY;
		ext = "lz4";
	} else if (strcmp(method, "bzip2") == 0) {
		type = BZIP2;
		ext = "bz2";
	} else {
		fprintf(stderr, "Only support following methods: ");
		for (int i = 0; SUP_LIST[i]; ++i)
			fprintf(stderr, "%s ", SUP_LIST[i]);
		fprintf(stderr, "\n");
		exit(1);
	}
	void *file;
	size_t size;
	mmap_ro(from, &file, &size);
	if (!to)
		snprintf(dest, sizeof(dest), "%s.%s", from, ext);
	else
		strcpy(dest, to);
	fprintf(stderr, "Compressing to [%s]\n\n", dest);
	int fd = open_new(dest);
	comp(type, fd, file, size);
	close(fd);
	munmap(file, size);
	if (!to)
		unlink(from);
}

