#include <bolt/Compression.hpp>
#include "bolt/Errors.hpp"

namespace lightningbolt {

	ErrorOr<std::vector<u8>> BoltDecompress(u8* input, usize decompressedSize) {
		u8* inptr = input;
		std::vector<u8> res;

		res.resize(decompressedSize);

		u8* pOut = res.data();
		u8* pEnd = res.data() + decompressedSize;

		i32 iVar3 = 0;
		i32 iVar6 = 0;
		u32 uVar5 = 0;
		u8* pbVar4 = nullptr; // outrun
		bool bVar1;

		while(pOut < pEnd) {
			auto uVar7 = *inptr++;

			if(uVar7 < 128) { // lookback/run?
				iVar3 = iVar3 + uVar5 * 8 + ((int)(uVar7 & 0x70) >> 4);
				pbVar4 = pOut + -(iVar6 * 0x10 + (uVar7 & 0xf) + 1);
				iVar6 = iVar3 + 1;

				if(iVar3 != -2) {
					do {
						*pOut = *pbVar4;
						pbVar4 = pbVar4 + 1;
						bVar1 = iVar6 != 0;
						pOut = pOut + 1;
						iVar6 = iVar6 + -1;
					} while(bVar1);
				}
				iVar6 = 0;
				iVar3 = 0;
				uVar5 = 0;
			} else if(uVar7 < 144) { // literal copy from stream
				iVar3 = uVar5 * 0x10 + (uVar7 & 0xf) + 1;
				while(iVar3 != 0) {
					iVar3 = iVar3 + -1;
					*pOut = *inptr++;
					pOut = pOut + 1;
				}
				iVar3 = 0;
				uVar5 = 0;
			} else if(uVar7 < 160) {
				uVar5 = uVar7 & 3;
				iVar3 = iVar3 + 1;
				iVar6 = (int)(uVar7 & 0xc) >> 2;
			} else if(uVar7 < 192) {
				uVar5 = uVar5 * 0x20 + (uVar7 & 0x1f);
				iVar3 = iVar3 + 1;
			} else {
				iVar3 = iVar3 + 1;
				iVar6 = iVar6 * 0x40 + (uVar7 & 0x3f);
			}
		}

		if(pOut != pEnd)
			return std::make_error_code(BoltErrc::DecompressionError);

		return res;
	}

} // namespace lightningbolt