import { execFile } from "node:child_process";
import { promisify } from "node:util";
import * as Clipboard from "@mariozechner/clipboard";

const execFileAsync = promisify(execFile);
const COMMAND_TIMEOUT_MS = 5_000;
const MAX_BUFFER_BYTES = 20 * 1024 * 1024;

export async function readClipboardText(): Promise<string | undefined> {
  const nativeText = await readClipboardTextViaNative();
  if (nativeText !== undefined) {
    return nativeText;
  }

  return await readClipboardTextViaCommands(process.platform, process.env);
}

async function readClipboardTextViaNative(): Promise<string | undefined> {
  try {
    if (!Clipboard.hasText()) {
      return undefined;
    }
    return await Clipboard.getText();
  } catch {
    return undefined;
  }
}

async function readClipboardTextViaCommands(
  platform: NodeJS.Platform,
  env: NodeJS.ProcessEnv,
): Promise<string | undefined> {
  if (env.TERMUX_VERSION) {
    return await runCommand("termux-clipboard-get", []);
  }

  if (platform === "darwin") {
    return await runCommand("pbpaste", []);
  }

  if (platform === "win32") {
    return await runCommand("powershell.exe", ["-NoProfile", "-Command", "Get-Clipboard -Raw"]);
  }

  if (platform === "linux") {
    if (isWSL(env)) {
      const windowsClipboard = await runCommand("powershell.exe", ["-NoProfile", "-Command", "Get-Clipboard -Raw"]);
      if (windowsClipboard !== undefined) {
        return windowsClipboard;
      }
    }

    if (env.WAYLAND_DISPLAY || env.XDG_SESSION_TYPE === "wayland") {
      const waylandClipboard = await runCommand("wl-paste", ["--no-newline"]);
      if (waylandClipboard !== undefined) {
        return waylandClipboard;
      }
    }

    if (env.DISPLAY) {
      const xclipClipboard = await runCommand("xclip", ["-selection", "clipboard", "-out"]);
      if (xclipClipboard !== undefined) {
        return xclipClipboard;
      }

      const xselClipboard = await runCommand("xsel", ["--clipboard", "--output"]);
      if (xselClipboard !== undefined) {
        return xselClipboard;
      }
    }
  }

  return undefined;
}

async function runCommand(command: string, args: string[]): Promise<string | undefined> {
  try {
    const { stdout } = await execFileAsync(command, args, {
      encoding: "utf8",
      timeout: COMMAND_TIMEOUT_MS,
      maxBuffer: MAX_BUFFER_BYTES,
      windowsHide: true,
    });
    return typeof stdout === "string" ? stdout : String(stdout);
  } catch {
    return undefined;
  }
}

function isWSL(env: NodeJS.ProcessEnv): boolean {
  return Boolean(env.WSL_DISTRO_NAME || env.WSLENV);
}