// Copyright 2008 Dolphin Emulator Project
// Licensed under GPLv2+
// Refer to the license.txt file included.

#ifdef _WIN32
#include <io.h>
#include <windows.h>
#endif

#include <algorithm>
#include <cinttypes>
#include <cstdio>
#include <cstring>
#include <memory>
#include <string>
#include <vector>
#include <zlib.h>

#include "Common/CommonTypes.h"
#include "Common/FileUtil.h"
#include "Common/Hash.h"
#include "Common/MsgHandler.h"
#include "Common/StringUtil.h"
#include "Common/Logging/Log.h"
#include "DiscIO/Blob.h"
#include "DiscIO/CompressedBlob.h"
#include "DiscIO/DiscScrubber.h"


namespace DiscIO
{

CompressedBlobReader::CompressedBlobReader(const std::string& filename) : m_file_name(filename)
{
	m_file.Open(filename, "rb");
	m_file_size = File::GetSize(filename);
	m_file.ReadArray(&m_header, 1);

	SetSectorSize(m_header.block_size);

	// cache block pointers and hashes
	m_block_pointers.resize(m_header.num_blocks);
	m_file.ReadArray(m_block_pointers.data(), m_header.num_blocks);
	m_hashes.resize(m_header.num_blocks);
	m_file.ReadArray(m_hashes.data(), m_header.num_blocks);

	m_data_offset = (sizeof(CompressedBlobHeader))
	              + (sizeof(u64)) * m_header.num_blocks  // skip block pointers
	              + (sizeof(u32)) * m_header.num_blocks; // skip hashes

	// A compressed block is never ever longer than a decompressed block, so just header.block_size should be fine.
	// I still add some safety margin.
	const u32 zlib_buffer_size = m_header.block_size + 64;
	m_zlib_buffer.resize(zlib_buffer_size);
}

std::unique_ptr<CompressedBlobReader> CompressedBlobReader::Create(const std::string& filename)
{
	if (IsGCZBlob(filename))
		return std::unique_ptr<CompressedBlobReader>(new CompressedBlobReader(filename));

	return nullptr;
}

CompressedBlobReader::~CompressedBlobReader()
{
}

// IMPORTANT: Calling this function invalidates all earlier pointers gotten from this function.
u64 CompressedBlobReader::GetBlockCompressedSize(u64 block_num) const
{
	u64 start = m_block_pointers[block_num];
	if (block_num < m_header.num_blocks - 1)
		return m_block_pointers[block_num + 1] - start;
	else if (block_num == m_header.num_blocks - 1)
		return m_header.compressed_data_size - start;
	else
		PanicAlert("GetBlockCompressedSize - illegal block number %i", (int)block_num);
	return 0;
}

bool CompressedBlobReader::GetBlock(u64 block_num, u8 *out_ptr)
{
	bool uncompressed = false;
	u32 comp_block_size = (u32)GetBlockCompressedSize(block_num);
	u64 offset = m_block_pointers[block_num] + m_data_offset;

	if (offset & (1ULL << 63))
	{
		if (comp_block_size != m_header.block_size)
			PanicAlert("Uncompressed block with wrong size");
		uncompressed = true;
		offset &= ~(1ULL << 63);
	}

	// clear unused part of zlib buffer. maybe this can be deleted when it works fully.
	memset(&m_zlib_buffer[comp_block_size], 0, m_zlib_buffer.size() - comp_block_size);

	m_file.Seek(offset, SEEK_SET);
	if (!m_file.ReadBytes(m_zlib_buffer.data(), comp_block_size))
	{
		PanicAlertT("The disc image \"%s\" is truncated, some of the data is missing.",
		            m_file_name.c_str());
		m_file.Clear();
		return false;
	}

	// First, check hash.
	u32 block_hash = HashAdler32(m_zlib_buffer.data(), comp_block_size);
	if (block_hash != m_hashes[block_num])
		PanicAlertT("The disc image \"%s\" is corrupt.\n"
		            "Hash of block %" PRIu64 " is %08x instead of %08x.",
		            m_file_name.c_str(),
		            block_num, block_hash, m_hashes[block_num]);

	if (uncompressed)
	{
		std::copy(m_zlib_buffer.begin(), m_zlib_buffer.begin() + comp_block_size, out_ptr);
	}
	else
	{
		z_stream z = {};
		z.next_in  = m_zlib_buffer.data();
		z.avail_in = comp_block_size;
		if (z.avail_in > m_header.block_size)
		{
			PanicAlert("We have a problem");
		}
		z.next_out  = out_ptr;
		z.avail_out = m_header.block_size;
		inflateInit(&z);
		int status = inflate(&z, Z_FULL_FLUSH);
		u32 uncomp_size = m_header.block_size - z.avail_out;
		if (status != Z_STREAM_END)
		{
			// this seem to fire wrongly from time to time
			// to be sure, don't use compressed isos :P
			PanicAlert("Failure reading block %" PRIu64 " - out of data and not at end.", block_num);
		}
		inflateEnd(&z);
		if (uncomp_size != m_header.block_size)
		{
			PanicAlert("Wrong block size");
			return false;
		}
	}
	return true;
}

bool CompressFileToBlob(const std::string& infile, const std::string& outfile, u32 sub_type,
						int block_size, CompressCB callback, void* arg)
{
	bool scrubbing = false;

	if (IsGCZBlob(infile))
	{
		PanicAlertT("\"%s\" is already compressed! Cannot compress it further.", infile.c_str());
		return false;
	}

	File::IOFile inf(infile, "rb");
	if (!inf)
	{
		PanicAlertT("Failed to open the input file \"%s\".", infile.c_str());
		return false;
	}

	File::IOFile f(outfile, "wb");
	if (!f)
	{
		PanicAlertT("Failed to open the output file \"%s\".\n"
		            "Check that you have permissions to write the target folder and that the media can be written.",
		            outfile.c_str());
		return false;
	}

	if (sub_type == 1)
	{
		if (!DiscScrubber::SetupScrub(infile, block_size))
		{
			PanicAlertT("\"%s\" failed to be scrubbed. Probably the image is corrupt.", infile.c_str());
			return false;
		}

		scrubbing = true;
	}

	z_stream z = {};
	if (deflateInit(&z, 9) != Z_OK)
	{
		DiscScrubber::Cleanup();
		return false;
	}

	callback(GetStringT("Files opened, ready to compress."), 0, arg);

	CompressedBlobHeader header;
	header.magic_cookie = kBlobCookie;
	header.sub_type   = sub_type;
	header.block_size = block_size;
	header.data_size  = File::GetSize(infile);

	// round upwards!
	header.num_blocks = (u32)((header.data_size + (block_size - 1)) / block_size);

	std::vector<u64> offsets(header.num_blocks);
	std::vector<u32> hashes(header.num_blocks);
	std::vector<u8> out_buf(block_size);
	std::vector<u8> in_buf(block_size);

	// seek past the header (we will write it at the end)
	f.Seek(sizeof(CompressedBlobHeader), SEEK_CUR);
	// seek past the offset and hash tables (we will write them at the end)
	f.Seek((sizeof(u64) + sizeof(u32)) * header.num_blocks, SEEK_CUR);

	// Now we are ready to write compressed data!
	u64 position = 0;
	int num_compressed = 0;
	int num_stored = 0;
	int progress_monitor = std::max<int>(1, header.num_blocks / 1000);
	bool success = true;

	for (u32 i = 0; i < header.num_blocks; i++)
	{
		if (i % progress_monitor == 0)
		{
			const u64 inpos = inf.Tell();
			int ratio = 0;
			if (inpos != 0)
				ratio = (int)(100 * position / inpos);

			std::string temp = StringFromFormat(GetStringT("%i of %i blocks. Compression ratio %i%%").c_str(),
			                                    i, header.num_blocks, ratio);
			bool was_cancelled = !callback(temp, (float)i / (float)header.num_blocks, arg);
			if (was_cancelled)
			{
				success = false;
				break;
			}
		}

		offsets[i] = position;

		size_t read_bytes;
		if (scrubbing)
			read_bytes = DiscScrubber::GetNextBlock(inf, in_buf.data());
		else
			inf.ReadArray(in_buf.data(), header.block_size, &read_bytes);
		if (read_bytes < header.block_size)
			std::fill(in_buf.begin() + read_bytes, in_buf.begin() + header.block_size, 0);

		int retval = deflateReset(&z);
		z.next_in   = in_buf.data();
		z.avail_in  = header.block_size;
		z.next_out  = out_buf.data();
		z.avail_out = block_size;

		if (retval != Z_OK)
		{
			ERROR_LOG(DISCIO, "Deflate failed");
			success = false;
			break;
		}

		int status = deflate(&z, Z_FINISH);
		int comp_size = block_size - z.avail_out;

		u8* write_buf;
		int write_size;
		if ((status != Z_STREAM_END) || (z.avail_out < 10))
		{
			//PanicAlert("%i %i Store %i", i*block_size, position, comp_size);
			// let's store uncompressed
			write_buf = in_buf.data();
			offsets[i] |= 0x8000000000000000ULL;
			write_size = block_size;
			num_stored++;
		}
		else
		{
			// let's store compressed
			//PanicAlert("Comp %i to %i", block_size, comp_size);
			write_buf = out_buf.data();
			write_size = comp_size;
			num_compressed++;
		}

		if (!f.WriteBytes(write_buf, write_size))
		{
			PanicAlertT(
				"Failed to write the output file \"%s\".\n"
				"Check that you have enough space available on the target drive.",
				outfile.c_str());
			success = false;
			break;
		}

		position += write_size;

		hashes[i] = HashAdler32(write_buf, write_size);
	}

	header.compressed_data_size = position;

	if (!success)
	{
		// Remove the incomplete output file.
		f.Close();
		File::Delete(outfile);
	}
	else
	{
		// Okay, go back and fill in headers
		f.Seek(0, SEEK_SET);
		f.WriteArray(&header, 1);
		f.WriteArray(offsets.data(), header.num_blocks);
		f.WriteArray(hashes.data(), header.num_blocks);
	}

	// Cleanup
	deflateEnd(&z);
	DiscScrubber::Cleanup();

	if (success)
	{
		callback(GetStringT("Done compressing disc image."), 1.0f, arg);
	}
	return success;
}

bool DecompressBlobToFile(const std::string& infile, const std::string& outfile, CompressCB callback, void* arg)
{
	if (!IsGCZBlob(infile))
	{
		PanicAlertT("File not compressed");
		return false;
	}

	std::unique_ptr<CompressedBlobReader> reader(CompressedBlobReader::Create(infile));
	if (!reader)
	{
		PanicAlertT("Failed to open the input file \"%s\".", infile.c_str());
		return false;
	}

	File::IOFile f(outfile, "wb");
	if (!f)
	{
		PanicAlertT(
			"Failed to open the output file \"%s\".\n"
			"Check that you have permissions to write the target folder and that the media can be written.",
			outfile.c_str());
		return false;
	}

	const CompressedBlobHeader &header = reader->GetHeader();
	static const size_t BUFFER_BLOCKS = 32;
	size_t buffer_size = header.block_size * BUFFER_BLOCKS;
	size_t last_buffer_size = header.block_size * (header.num_blocks % BUFFER_BLOCKS);
	std::vector<u8> buffer(buffer_size);
	u32 num_buffers = (header.num_blocks + BUFFER_BLOCKS - 1) / BUFFER_BLOCKS;
	int progress_monitor = std::max<int>(1, num_buffers / 100);
	bool success = true;

	for (u64 i = 0; i < num_buffers; i++)
	{
		if (i % progress_monitor == 0)
		{
			bool was_cancelled = !callback(GetStringT("Unpacking"), (float)i / (float)num_buffers, arg);
			if (was_cancelled)
			{
				success = false;
				break;
			}
		}
		const size_t sz = i == num_buffers - 1 ? last_buffer_size : buffer_size;
		reader->Read(i * buffer_size, sz, buffer.data());
		if (!f.WriteBytes(buffer.data(), sz))
		{
			PanicAlertT(
				"Failed to write the output file \"%s\".\n"
				"Check that you have enough space available on the target drive.",
				outfile.c_str());
			success = false;
			break;
		}
	}

	if (!success)
	{
		// Remove the incomplete output file.
		f.Close();
		File::Delete(outfile);
	}
	else
	{
		f.Resize(header.data_size);
	}

	return true;
}

bool IsGCZBlob(const std::string& filename)
{
	File::IOFile f(filename, "rb");

	CompressedBlobHeader header;
	return f.ReadArray(&header, 1) && (header.magic_cookie == kBlobCookie);
}

}  // namespace