// Deno-specific ffi code
import { IFFI } from '../common/runtime.ts';

let suffix = '';
switch (Deno.build.os) {
	case 'windows':
		suffix = 'dll';
		break;
	case 'darwin':
		suffix = 'dylib';
		break;
	default:
		suffix = 'so.6';
		break;
}

const cSharedLib = `libc.${suffix}`;
const cStdLib = Deno.dlopen(
	cSharedLib,
	{
		tcgetattr: {
			parameters: ['i32', 'pointer'],
			result: 'i32',
		},
		tcsetattr: {
			parameters: ['i32', 'i32', 'pointer'],
			result: 'i32',
		},
		cfmakeraw: {
			parameters: ['pointer'],
			result: 'void',
		},
	} as const,
);

const { tcgetattr, tcsetattr, cfmakeraw } = cStdLib.symbols;
let closed = false;
const DenoFFI: IFFI = {
	tcgetattr,
	tcsetattr,
	cfmakeraw,
	getPointer: Deno.UnsafePointer.of,
	close: () => {
		if (!closed) {
			cStdLib.close();
			closed = true;
		}

		// Do nothing if FFI library was already closed
	},
};

export default DenoFFI;