<?php declare(strict_types=1);

namespace Kilo;

use FFI;

$ffi = FFI::load(__DIR__ . '/ffi.h');
$original_termios = $ffi->new('struct termios');

function enableRawMode(): void
{
	global $ffi;
	global $original_termios;

	register_shutdown_function('Kilo\\disableRawMode');

	// Populate the original terminal settings
	$res = $ffi->tcgetattr(STDIN_FILENO, FFI::addr($original_termios));
	if ($res === -1)
	{
		die('tcgetattr');
	}

	// So, the only thing that seems to really matter here is that c_oflag is 0...
	$termios = clone $original_termios;
	$termios->c_iflag = $termios->c_iflag & ~(BRKINT | ICRNL | INPCK | ISTRIP | IXON);
	$termios->c_oflag = 0; // $termios->c_oflag && ~(OPOST);
	$termios->c_cflag |= (CS8);
	$termios->c_lflag = $termios->c_lflag & ~(_ECHO | ICANON | IEXTEN | ISIG);
	$termios->c_cc[VMIN] = 0;
	$termios->c_cc[VTIME] = 1;

	// Turn on raw mode
	$res = $ffi->tcsetattr(STDIN_FILENO, TCSAFLUSH, FFI::addr($termios));
	if ($res === -1)
	{
		die('tcsetattr');
	}
}

function disableRawMode(): void
{
	global $ffi;
	global $original_termios;

	$res = $ffi->tcsetattr(STDIN_FILENO, TCSAFLUSH, FFI::addr($original_termios));

	echo "\n";

	if ($res === -1)
	{
		die('tcsetattr');
	}
}

function read_stdin(int $len = 128): string
{
	$handle = fopen('php://stdin', 'rb');
	$input = fread($handle, $len);
	fclose($handle);

	return $input;
}

function write_stdout(string $str, int $len = NULL): int
{
	$handle = fopen('php://stdout', 'ab');
	$res = (is_int($len))
		? fwrite($handle, $str, $len)
		: fwrite($handle, $str);

	fclose($handle);

	return $res;
}

function read_stdout(int $len = 128): string
{
	$handle = fopen('php://stdout', 'rb');
	$input = fread($handle, $len);

	$input = rtrim($input);
	fclose($handle);

	return $input;
}

/**
 * Do bit twiddling to convert a letter into
 * its Ctrl-letter equivalent
 *
 * @param string $char
 * @return int
 */
function ctrl_key(string $char): int
{
	// b1,100,001 (a) & b0,011,111 = b0,000,001
	// b1,100,010 (b) & b0,011,111 = b0,000,010
	return ord($char) & 0x1f;
}