import { RunTimeType } from './runtime.ts';

/**
 * The size of terminal in rows and columns
 */
export interface ITerminalSize {
	rows: number;
	cols: number;
}

/**
 * The native functions for getting/setting terminal settings
 */
export interface IFFI {
	/**
	 * Get the existing termios settings (for canonical mode)
	 */
	tcgetattr(fd: number, termiosPtr: unknown): number;

	/**
	 * Update the termios settings
	 */
	tcsetattr(fd: number, act: number, termiosPtr: unknown): number;

	/**
	 * Update the termios pointer with raw mode settings
	 */
	cfmakeraw(termiosPtr: unknown): void;

	/**
	 * Convert a TypedArray to an opaque pointer for ffi calls
	 */
	// deno-lint-ignore no-explicit-any
	getPointer(ta: any): unknown;

	/**
	 * Closes the FFI handle
	 */
	close(): void;
}

// ----------------------------------------------------------------------------
// Runtime adapter interfaces
// ----------------------------------------------------------------------------

/**
 * The common interface for runtime adapters
 */
export interface IRuntime {
	/**
	 * The name of the runtime
	 */
	name: RunTimeType;

	/**
	 * Runtime-specific terminal functionality
	 */
	term: {
		/**
		 * The arguments passed to the program on launch
		 */
		argv: string[];

		/**
		 * The generator function returning chunks of input from the stdin stream
		 */
		inputLoop(): AsyncGenerator<Uint8Array, null>;

		/**
		 * Get the size of the terminal
		 */
		getTerminalSize(): Promise<ITerminalSize>;

		/**
		 * Get the current chunk of input, if it exists
		 */
		readStdin(): Promise<string | null>;

		/**
		 * Get the raw chunk of input
		 */
		readStdinRaw(): Promise<Uint8Array | null>;

		/**
		 * Pipe a string to stdout
		 */
		writeStdout(s: string): Promise<void>;
	};

	/**
	 * Runtime-specific file system io
	 */
	file: {
		openFile(path: string): Promise<string>;
		appendFile(path: string, contents: string): Promise<void>;
		saveFile(path: string, contents: string): Promise<void>;
	};

	/**
	 * Set up an event handler
	 *
	 * @param eventName - The event to listen for
	 * @param handler - The event handler
	 */
	onEvent: (
		eventName: string,
		handler: (e: Event | ErrorEvent) => void,
	) => void;

	/**
	 * Set a beforeExit/beforeUnload event handler for the runtime
	 * @param cb - The event handler
	 */
	onExit(cb: () => void): void;

	/**
	 * Stop execution
	 *
	 * @param code
	 */
	exit(code?: number): void;
}

/**
 * Runtime-specific terminal functionality
 */
export type ITerminal = IRuntime['term'];

/**
 * Runtime-specific file handling
 */
export type IFileIO = IRuntime['file'];

// ----------------------------------------------------------------------------
// General types
// ----------------------------------------------------------------------------

export class Position {
	public x: number;
	public y: number;

	private constructor(x: number, y: number) {
		this.x = x;
		this.y = y;
	}

	public static at(x: number, y: number): Position {
		return new Position(x, y);
	}

	public static default(): Position {
		return new Position(0, 0);
	}
}

// ----------------------------------------------------------------------------
// Testing
// ----------------------------------------------------------------------------

/**
 * The shared test interface, so tests can be run by both runtimes
 */
export interface ITestBase {
	assertEquals(actual: unknown, expected: unknown): void;
	assertExists(actual: unknown): void;
	assertFalse(actual: boolean): void;
	assertInstanceOf(actual: unknown, expectedType: any): void;
	assertNotEquals(actual: unknown, expected: unknown): void;
	assertNull(actual: unknown): void;
	assertStrictEquals(actual: unknown, expected: unknown): void;
	assertTrue(actual: boolean): void;
	testSuite(testObj: any): void;
}