#include "io-helper.h"

#include <system_error>

std::FILE* core::open_file(const char* file_path, const char* mode)
{
	std::FILE* file = std::fopen(file_path, mode);
	if (!file)
		throw std::system_error(errno, std::system_category());

	return file;
}

void core::seek_file_to_beginning(std::FILE* file, long offset)
{
	const int result = std::fseek(file, offset, SEEK_SET);
	if (result != 0)
		throw std::system_error(errno, std::system_category());
}

void core::seek_file_relatively(std::FILE* file, long offset)
{
	const int result = std::fseek(file, offset, SEEK_CUR);
	if (result != 0)
		throw std::system_error(errno, std::system_category());
}

void core::seek_file_to_end(std::FILE* file, long offset)
{
	const int result = std::fseek(file, offset, SEEK_END);
	if (result != 0)
		throw std::system_error(errno, std::system_category());
}

long core::get_file_offset(std::FILE* file)
{
	const long offset = std::ftell(file);
	if (offset < 0)
		throw std::system_error(errno, std::system_category());

	return offset;
}

std::size_t core::read_from_file(void* buffer, std::size_t size, std::size_t count, std::FILE* file)
{
	const std::size_t objects_read = std::fread(buffer, size, count, file);
	if (objects_read < count)
	{
		if (std::feof(file))
			throw std::runtime_error("Failed to read from file: End-of-file reached.");
		else
			throw std::runtime_error("Failed to read from file: Unknown error.");
	}

	return objects_read;
}

std::size_t core::write_to_file(const void* buffer, std::size_t size, std::size_t count, std::FILE* file)
{
	const std::size_t objects_written = std::fwrite(buffer, size, count, file);
	if (objects_written < count)
		throw std::runtime_error("Failed to write to file.");

	return objects_written;
}

void core::close_file(std::FILE* file)
{
	int result = std::fclose(file);
	if (result != 0)
		throw std::runtime_error("Failed to close file.");
}