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

#include <zenutil/invocationhistory.h>

#include <zencore/basicfile.h>
#include <zencore/compactbinary.h>
#include <zencore/filesystem.h>
#include <zencore/iobuffer.h>
#include <zencore/memoryview.h>
#include <zencore/process.h>
#include <zencore/uid.h>
#include <zenutil/config/commandlineoptions.h>

ZEN_THIRD_PARTY_INCLUDES_START
#include <json11.hpp>
ZEN_THIRD_PARTY_INCLUDES_END

#include <system_error>

namespace zen {

namespace {

	constexpr size_t		   kMaxRecords		= 100;
	constexpr std::string_view kHistoryFileName = "invocations.jsonl";

	// Safety cap. With 100 records at typical ~500-1000 bytes each the file
	// normally sits around 50-100 KB. If it has grown past this threshold
	// (external corruption, runaway producer, another tool writing garbage)
	// we refuse to read it and start fresh with just the new record. Keeps
	// LogInvocation from slowing startup on a pathological file.
	constexpr uintmax_t kMaxReadSize = 1 * 1024 * 1024;	 // 1 MB

	bool ExecutionHistoryDisabled(int argc, char** argv)
	{
		for (int I = 1; I < argc; ++I)
		{
			if (argv[I] == nullptr)
			{
				continue;
			}
			std::string_view A = argv[I];
			if (A == "--enable-execution-history=false" || A == "--enable-execution-history=0" || A == "--enable-execution-history=no")
			{
				return true;
			}
		}
		return false;
	}

	std::filesystem::path ResolveHistoryDir()
	{
#if ZEN_PLATFORM_WINDOWS
		std::optional<std::string> LocalAppData = GetEnvVariable("LOCALAPPDATA");
		if (LocalAppData && !LocalAppData->empty())
		{
			return std::filesystem::path(*LocalAppData) / "Epic" / "Zen" / "History";
		}
#endif
		std::filesystem::path SystemRoot = PickDefaultSystemRootDirectory();
		if (SystemRoot.empty())
		{
			return {};
		}
		return SystemRoot / "History";
	}

	std::string BuildJsonRecord(const HistoryRecord& Rec)
	{
		json11::Json::object Obj{
			{"id", Rec.Id},
			{"ts", Rec.Ts},
			{"exe", Rec.Exe},
			{"pid", static_cast<int>(Rec.Pid)},
			{"cwd", Rec.Cwd},
			{"path", Rec.Path},
			{"cmdline", Rec.CmdLine},
		};
		if (!Rec.Mode.empty())
		{
			Obj.emplace("mode", Rec.Mode);
		}
		return json11::Json(Obj).dump();
	}

	bool ParseJsonRecord(std::string_view Line, HistoryRecord& OutRec)
	{
		std::string	 Err;
		json11::Json J = json11::Json::parse(std::string(Line), Err);
		if (!Err.empty() || !J.is_object())
		{
			return false;
		}
		OutRec.Id	   = J["id"].string_value();
		OutRec.Ts	   = J["ts"].string_value();
		OutRec.Exe	   = J["exe"].string_value();
		OutRec.Mode	   = J["mode"].string_value();
		OutRec.Cwd	   = J["cwd"].string_value();
		OutRec.Path	   = J["path"].string_value();
		OutRec.CmdLine = J["cmdline"].string_value();
		OutRec.Pid	   = static_cast<uint32_t>(J["pid"].int_value());
		return true;
	}

	std::vector<std::string> ReadHistoryLines(const std::filesystem::path& Path)
	{
		std::vector<std::string> Lines;

		std::error_code		 SizeEc;
		const std::uintmax_t FileSize = std::filesystem::file_size(Path, SizeEc);
		if (SizeEc || FileSize > kMaxReadSize)
		{
			return Lines;
		}

		FileContents Contents = ReadFile(Path);
		if (!Contents)
		{
			return Lines;
		}
		IoBuffer	 Flat  = Contents.Flatten();
		const char*	 Data  = static_cast<const char*>(Flat.GetData());
		const size_t Size  = Flat.GetSize();
		size_t		 Start = 0;
		for (size_t I = 0; I < Size; ++I)
		{
			if (Data[I] == '\n')
			{
				if (I > Start)
				{
					size_t LineEnd = I;
					if (LineEnd > Start && Data[LineEnd - 1] == '\r')
					{
						--LineEnd;
					}
					if (LineEnd > Start)
					{
						Lines.emplace_back(Data + Start, LineEnd - Start);
					}
				}
				Start = I + 1;
			}
		}
		if (Start < Size)
		{
			Lines.emplace_back(Data + Start, Size - Start);
		}
		return Lines;
	}

}  // namespace

std::filesystem::path
GetInvocationHistoryPath() noexcept
{
	try
	{
		std::filesystem::path Dir = ResolveHistoryDir();
		if (Dir.empty())
		{
			return {};
		}
		return Dir / kHistoryFileName;
	}
	catch (...)
	{
		return {};
	}
}

void
LogInvocation(std::string_view						  Exe,
			  std::string_view						  Mode,
			  int									  argc,
			  char**								  argv,
			  std::initializer_list<std::string_view> ExcludeSubcommands) noexcept
{
	try
	{
		if (ExecutionHistoryDisabled(argc, argv))
		{
			return;
		}

		if (argc >= 2 && argv[1] != nullptr)
		{
			std::string_view A1 = argv[1];
			for (std::string_view Excluded : ExcludeSubcommands)
			{
				if (A1 == Excluded)
				{
					return;
				}
			}
		}

		std::filesystem::path Dir = ResolveHistoryDir();
		if (Dir.empty())
		{
			return;
		}

		std::error_code Ec;
		CreateDirectories(Dir, Ec);
		if (Ec)
		{
			return;
		}

		std::filesystem::path Path = Dir / kHistoryFileName;

		HistoryRecord Rec;
		Rec.Id	 = Oid::NewOid().ToString();
		Rec.Ts	 = DateTime::Now().ToIso8601();
		Rec.Exe	 = std::string(Exe);
		Rec.Mode = std::string(Mode);

		std::error_code CwdEc;
		Rec.Cwd = std::filesystem::current_path(CwdEc).string();

		Rec.Path = GetRunningExecutablePath().string();
		Rec.Pid	 = static_cast<uint32_t>(GetCurrentProcessId());

		std::string Raw = GetRawCommandLine();
		if (Raw.empty())
		{
			std::vector<std::string> Args;
			Args.reserve(argc);
			for (int I = 0; I < argc; ++I)
			{
				if (argv[I] != nullptr)
				{
					Args.emplace_back(argv[I]);
				}
			}
			Raw = BuildCommandLine(Args);
		}
		ScrubSensitiveValues(Raw);
		Rec.CmdLine = std::move(Raw);

		std::vector<std::string> Lines = ReadHistoryLines(Path);
		if (Lines.size() >= kMaxRecords)
		{
			Lines.erase(Lines.begin(), Lines.begin() + (Lines.size() - (kMaxRecords - 1)));
		}
		Lines.push_back(BuildJsonRecord(Rec));

		std::string NewContents;
		size_t		TotalSize = 0;
		for (const std::string& L : Lines)
		{
			TotalSize += L.size() + 1;
		}
		NewContents.reserve(TotalSize);
		for (const std::string& L : Lines)
		{
			NewContents.append(L);
			NewContents.push_back('\n');
		}

		std::error_code WriteEc;
		TemporaryFile::SafeWriteFile(Path, MemoryView(NewContents.data(), NewContents.size()), WriteEc);
	}
	catch (...)
	{
	}
}

std::vector<HistoryRecord>
ReadInvocationHistory(size_t MaxRecords)
{
	std::vector<HistoryRecord> Records;
	try
	{
		std::filesystem::path Path = GetInvocationHistoryPath();
		if (Path.empty())
		{
			return Records;
		}

		std::vector<std::string> Lines = ReadHistoryLines(Path);
		if (Lines.size() > MaxRecords)
		{
			Lines.erase(Lines.begin(), Lines.begin() + (Lines.size() - MaxRecords));
		}

		Records.reserve(Lines.size());
		for (const std::string& L : Lines)
		{
			HistoryRecord Rec;
			if (ParseJsonRecord(L, Rec))
			{
				Records.push_back(std::move(Rec));
			}
		}
	}
	catch (...)
	{
	}
	return Records;
}

void
invocationhistory_forcelink()
{
}

}  // namespace zen