co-mono/packages/tui/src/terminal.ts

/**
 * Minimal terminal interface for TUI
 */
export interface Terminal {
	// Start the terminal with input and resize handlers
	start(onInput: (data: string) => void, onResize: () => void): void;

	// Stop the terminal and restore state
	stop(): void;

	// Write output to terminal
	write(data: string): void;

	// Get terminal dimensions
	get columns(): number;
	get rows(): number;

	// Cursor positioning (relative to current position)
	moveBy(lines: number): void; // Move cursor up (negative) or down (positive) by N lines

	// Cursor visibility
	hideCursor(): void; // Hide the cursor
	showCursor(): void; // Show the cursor

	// Clear operations
	clearLine(): void; // Clear current line
	clearFromCursor(): void; // Clear from cursor to end of screen
	clearScreen(): void; // Clear entire screen and move cursor to (0,0)
}

/**
 * Real terminal using process.stdin/stdout
 */
export class ProcessTerminal implements Terminal {
	private wasRaw = false;
	private inputHandler?: (data: string) => void;
	private resizeHandler?: () => void;

	start(onInput: (data: string) => void, onResize: () => void): void {
		this.inputHandler = onInput;
		this.resizeHandler = onResize;

		// Save previous state and enable raw mode
		this.wasRaw = process.stdin.isRaw || false;
		if (process.stdin.setRawMode) {
			process.stdin.setRawMode(true);
		}
		process.stdin.setEncoding("utf8");
		process.stdin.resume();

		// Enable bracketed paste mode - terminal will wrap pastes in \x1b[200~ ... \x1b[201~
		process.stdout.write("\x1b[?2004h");

		// Enable Kitty keyboard protocol (disambiguate escape codes)
		// This makes terminals like Ghostty, Kitty, WezTerm send enhanced key sequences
		// e.g., Shift+Enter becomes \x1b[13;2u instead of just \r
		// See: https://sw.kovidgoyal.net/kitty/keyboard-protocol/
		process.stdout.write("\x1b[>1u");

		// Set up event handlers
		process.stdin.on("data", this.inputHandler);
		process.stdout.on("resize", this.resizeHandler);
	}

	stop(): void {
		// Disable bracketed paste mode
		process.stdout.write("\x1b[?2004l");

		// Disable Kitty keyboard protocol (pop the flags we pushed)
		process.stdout.write("\x1b[<u");

		// Remove event handlers
		if (this.inputHandler) {
			process.stdin.removeListener("data", this.inputHandler);
			this.inputHandler = undefined;
		}
		if (this.resizeHandler) {
			process.stdout.removeListener("resize", this.resizeHandler);
			this.resizeHandler = undefined;
		}

		// Restore raw mode state
		if (process.stdin.setRawMode) {
			process.stdin.setRawMode(this.wasRaw);
		}
	}

	write(data: string): void {
		process.stdout.write(data);
	}

	get columns(): number {
		return process.stdout.columns || 80;
	}

	get rows(): number {
		return process.stdout.rows || 24;
	}

	moveBy(lines: number): void {
		if (lines > 0) {
			// Move down
			process.stdout.write(`\x1b[${lines}B`);
		} else if (lines < 0) {
			// Move up
			process.stdout.write(`\x1b[${-lines}A`);
		}
		// lines === 0: no movement
	}

	hideCursor(): void {
		process.stdout.write("\x1b[?25l");
	}

	showCursor(): void {
		process.stdout.write("\x1b[?25h");
	}

	clearLine(): void {
		process.stdout.write("\x1b[K");
	}

	clearFromCursor(): void {
		process.stdout.write("\x1b[J");
	}

	clearScreen(): void {
		process.stdout.write("\x1b[2J\x1b[H"); // Clear screen and move to home (1,1)
	}
}