module std::io;
import libc;

struct File (InStream, OutStream)
{
	CFile file;
}

module std::io::file;
import libc, std::io::path, std::io::os;

fn File? open(String filename, String mode)
{
	return from_handle(os::native_fopen(filename, mode));
}

fn File? open_path(Path path, String mode)
{
	return from_handle(os::native_fopen(path.str_view(), mode));
}

fn bool exists(String file) => @pool()
{
	return os::native_file_or_dir_exists(file);
}

fn File from_handle(CFile file)
{
	return { .file = file };
}

fn bool is_file(String path)
{
	return os::native_is_file(path);
}

fn bool is_dir(String path)
{
	return os::native_is_dir(path);
}

fn usz? get_size(String path)
{
	return os::native_file_size(path);
}

fn void? delete(String filename)
{
	return os::native_remove(filename) @inline;
}


<*
 @require self.file != null
*>
fn void? File.reopen(&self, String filename, String mode)
{
	self.file = os::native_freopen(self.file, filename, mode)!;
}

<*
 @require self.file != null
*>
fn usz? File.seek(&self, isz offset, Seek seek_mode = Seek.SET) @dynamic
{
	os::native_fseek(self.file, offset, seek_mode)!;
	return os::native_ftell(self.file);
}


/*
Implement later
<*
 @require self.file == null
*>
fn void? File.memopen(File* file, char[] data, String mode)
{
	@pool()
	{
		file.file = libc::memopen(data.ptr, data.len, mode.to_temp_zstr(), file.file);
		// TODO errors
	};
}
*/


<*
 @require self.file != null
*>
fn void? File.write_byte(&self, char c) @dynamic
{
	return os::native_fputc(c, self.file);
}

<*
 @param [&inout] self
*>
fn void? File.close(&self) @inline @dynamic
{
	if (self.file && libc::fclose(self.file))
	{
		switch (libc::errno())
		{
			case errno::ECONNRESET:
			case errno::EBADF: return io::FILE_NOT_VALID?;
			case errno::EINTR: return io::INTERRUPTED?;
			case errno::EDQUOT:
			case errno::EFAULT:
			case errno::EAGAIN:
			case errno::EFBIG:
			case errno::ENETDOWN:
			case errno::ENETUNREACH:
			case errno::ENOSPC:
			case errno::EIO: return io::INCOMPLETE_WRITE?;
			default: return io::UNKNOWN_ERROR?;
		}
	}
	self.file = null;
}

<*
 @require self.file != null
*>
fn bool File.eof(&self) @inline
{
	return libc::feof(self.file) != 0;
}

<*
 @param [in] buffer
*>
fn usz? File.read(&self, char[] buffer) @dynamic
{
	return os::native_fread(self.file, buffer);
}

<*
 @param [out] buffer
 @require self.file != null : `File must be initialized`
*>
fn usz? File.write(&self, char[] buffer) @dynamic
{
	return os::native_fwrite(self.file, buffer);
}

fn Fd File.fd(self) @if(env::LIBC)
{
	return libc::fileno(self.file);
}

fn bool File.isatty(self) @if(env::LIBC)
{
	return libc::isatty(self.fd()) > 0;
}

fn char? File.read_byte(&self) @dynamic
{
	int c = libc::fgetc(self.file);
	if (c == -1) return io::EOF?;
	return (char)c;
}

<*
 Load up to buffer.len characters. Returns io::OVERFLOW if the file is longer
 than the buffer.

 @param filename : "The path to the file to read"
 @param [in] buffer : "The buffer to read to"
*>
fn char[]? load_buffer(String filename, char[] buffer)
{
	File file = open(filename, "rb")!;
	defer (void)file.close();
	usz len = file.seek(0, END)!;
	if (len > buffer.len) return io::OVERFLOW?;
	file.seek(0, SET)!;
	usz read = 0;
	while (read < len)
	{
		read += file.read(buffer[read:len - read])!;
	}
	return buffer[:len];

}

fn char[]? load(Allocator allocator, String filename)
{
	File file = open(filename, "rb")!;
	defer (void)file.close();
	usz len = file.seek(0, END)!;
	file.seek(0, SET)!;
	char* data = allocator::malloc_try(allocator, len)!;
	defer catch allocator::free(allocator, data);
	usz read = 0;
	while (read < len)
	{
		read += file.read(data[read:len - read])!;
	}
	return data[:len];
}

fn char[]? load_path(Allocator allocator, Path path) => load(allocator, path.str_view());

fn char[]? load_temp(String filename) => load(tmem, filename);

fn char[]? load_path_temp(Path path) => load_temp(path.str_view());

fn void? save(String filename, char[] data)
{
	File file = open(filename, "wb")!;
	defer (void)file.close();
	while (data.len)
	{
		usz written = file.write(data)!;
		data = data[written..];
	}
}

<*
 @require self.file != null : `File must be initialized`
*>
fn void? File.flush(&self) @dynamic
{
	libc::fflush(self.file);
}