#pragma once

#include <string>

#include <fstream>

#include <optional>

#include <cerrno>

#include <filesystem>

namespace codeql {

// Only the first process trying to create a `TargetFile` for a given `target` is allowed to do

// so, all others will have `create` return `std::nullopt`.

// The content streamed to the `TargetFile` is written to `workingDir/target`, and is moved onto

// `targetDir/target` on destruction.

class TargetFile {

std::filesystem::path workingPath;

std::filesystem::path targetPath;

std::ofstream out;

public:

static std::optional<TargetFile> create(const std::filesystem::path& target,

const std::filesystem::path& targetDir,

const std::filesystem::path& workingDir);

~TargetFile() { commit(); }

TargetFile(TargetFile&& other) = default;

// move assignment deleted as non-trivial and not needed

TargetFile& operator=(TargetFile&& other) = delete;

template <typename T>

TargetFile& operator<<(T&& value) {

errno = 0;

out << value;

checkOutput("write to");

return *this;

}

const std::filesystem::path& target() const { return targetPath; }

private:

TargetFile(const std::filesystem::path& target,

const std::filesystem::path& targetDir,

const std::filesystem::path& workingDir);

bool init();

void checkOutput(const char* action);

void commit();

};

} // namespace codeql