import { execSync } from "node:child_process";
import type { ClipboardImage } from "@oh-my-pi/pi-natives";
import * as native from "@oh-my-pi/pi-natives";

const hasDisplay = process.platform !== "linux" || Boolean(process.env.DISPLAY || process.env.WAYLAND_DISPLAY);

/**
 * Copy text to the system clipboard.
 *
 * Emits OSC 52 first when running in a real terminal (works over SSH/mosh),
 * then attempts native clipboard copy as best-effort for local sessions.
 * On Termux, tries `termux-clipboard-set` before native.
 *
 * @param text - UTF-8 text to place on the clipboard.
 */
export async function copyToClipboard(text: string): Promise<void> {
	if (process.stdout.isTTY) {
		const onError = (err: unknown) => {
			process.stdout.off("error", onError);
			// Prevent unhandled 'error' from crashing the process when stdout is a closed pipe.
			if ((err as NodeJS.ErrnoException | null | undefined)?.code === "EPIPE") {
				return;
			}
		};
		try {
			const encoded = Buffer.from(text).toString("base64");
			const osc52 = `\x1b]52;c;${encoded}\x07`;
			process.stdout.on("error", onError);
			process.stdout.write(osc52, err => {
				process.stdout.off("error", onError);
				// If stdout is closed (e.g. piped to a process that exits early),
				// ignore EPIPE and proceed with native clipboard best-effort.
				if ((err as NodeJS.ErrnoException | null | undefined)?.code === "EPIPE") {
					return;
				}
			});
		} catch (err) {
			process.stdout.off("error", onError);
			if ((err as NodeJS.ErrnoException | null | undefined)?.code !== "EPIPE") {
				// Ignore all write failures (OSC 52 is best-effort).
			}
		}
	}

	// Also try native tools (best effort for local sessions)
	try {
		if (process.env.TERMUX_VERSION) {
			try {
				execSync("termux-clipboard-set", { input: text, timeout: 5000 });
				return;
			} catch {
				// Fall through to native
			}
		}

		await native.copyToClipboard(text);
	} catch {
		// Ignore — clipboard copy is best-effort
	}
}

/**
 * Read an image from the system clipboard.
 *
 * Returns null on Termux (no image clipboard support) or when no display
 * server is available (headless/SSH without forwarding).
 *
 * @returns PNG payload or null when no image is available.
 */
export async function readImageFromClipboard(): Promise<ClipboardImage | null> {
	if (process.env.TERMUX_VERSION) {
		return null;
	}

	if (!hasDisplay) {
		return null;
	}

	return (await native.readImageFromClipboard()) ?? null;
}