// Copyright Epic Games, Inc. All Rights Reserved.

#include "oplogreferencedset.h"

#include "projectstore.h"

#include <zencore/iobuffer.h>
#include <zencore/logging.h>
#include <zencore/string.h>

namespace zen {

std::optional<OplogReferencedSet>
OplogReferencedSet::LoadFromChunk(const IoBuffer& ChunkData)
{
	using namespace std::literals;

	if (!ChunkData || ChunkData.Size() == 0)
	{
		return std::optional<OplogReferencedSet>();
	}
	std::string_view ChunkText(reinterpret_cast<const char*>(ChunkData.Data()), ChunkData.Size());

	AsciiSet	TrimWhitespace(" \t\r\n");
	const char* FirstNonComment = nullptr;
	uint64_t	Version			= 0;

	// Parse the initial comment block: the leading block of empty or comment lines.
	ForEachStrTok(ChunkText, '\n', [&Version, &FirstNonComment, &TrimWhitespace](std::string_view Line) {
		Line = AsciiSet::TrimSuffixWith(AsciiSet::TrimPrefixWith(Line, TrimWhitespace), TrimWhitespace);
		if (Line.empty())
		{
			return true;  // empty line, keep reading
		}
		if (!Line.starts_with('#'))
		{
			FirstNonComment = Line.data();
			return false;  // non-comment line, stop
		}

		// Comment line in the header block of comments in the file. Interpret it if it is a version line.
		// Skip past the '#' and whitespace.
		Line.remove_prefix(1);
		Line = AsciiSet::TrimPrefixWith(Line, TrimWhitespace);

		// Parse "# Version <uint64>".
		constexpr std::string_view VersionStr("Version "sv);
		if (Line.starts_with(VersionStr))
		{
			std::string_view VersionToken = Line;
			VersionToken.remove_prefix(VersionStr.length());
			VersionToken.remove_suffix(AsciiSet::TrimPrefixWithout(VersionToken, TrimWhitespace).length());
			std::optional<uint64_t> ParsedVersion = ParseInt<uint64_t>(VersionToken);
			if (ParsedVersion)
			{
				Version = *ParsedVersion;
			}
		}
		return true;
	});

	// Report no referencedset if the version is below our minimum version.
	constexpr uint64_t MinSupportedVersion = 1;
	if (Version < MinSupportedVersion)
	{
		ZEN_INFO("ReferencedSet is below the minimum supported version, ignoring it. Version: {}, minimum version: {}.",
				 Version,
				 MinSupportedVersion);
		return std::optional<OplogReferencedSet>();
	}

	// Parse the remaining lines after the leading comment block.
	ChunkText.remove_prefix(FirstNonComment ? FirstNonComment - ChunkText.data() : ChunkText.length());

	OplogReferencedSet Result;
	ForEachStrTok(ChunkText, '\n', [&Result, &TrimWhitespace](std::string_view Line) {
		Line = AsciiSet::TrimSuffixWith(AsciiSet::TrimPrefixWith(Line, TrimWhitespace), TrimWhitespace);
		if (!Line.empty() && !Line.starts_with('#'))
		{
			Result.Emplace(OpKeyStringAsOid(Line));
		}
		return true;
	});
	return std::optional<OplogReferencedSet>(std::move(Result));
}

void
OplogReferencedSet::Emplace(Oid OplogId)
{
	Set.emplace(OplogId);
}

void
OplogReferencedSet::Clear()
{
	Set.clear();
}

bool
OplogReferencedSet::Contains(Oid OplogId, std::string_view OplogKey)
{
	// A referencedset always includes all non-package keys
	if (OplogKey.empty() || !OplogKey.starts_with("/"))
	{
		return true;
	}
	return Set.contains(OplogId);
}

}  // namespace zen