import { existsSync } from "node:fs";
import path from "node:path";
import { spawnSync } from "node:child_process";
import { fileURLToPath } from "node:url";

const rootDir = path.resolve(path.dirname(fileURLToPath(import.meta.url)), "..");

const WINDOWS_BIN_FILES = ["launcher.exe", "bun.exe"];

function ensureIconIco() {
  const iconPath = path.join(rootDir, "assets/icon.ico");
  if (existsSync(iconPath)) {
    return iconPath;
  }

  const sources = [
    path.join(rootDir, "assets/farmcontrolhosticon.png"),
    path.join(rootDir, "assets/icon.png"),
  ];
  const source = sources.find((candidate) => existsSync(candidate));
  if (!source) {
    throw new Error(
      "apply-windows-launcher-icon: assets/icon.ico not found and no source PNG to generate it",
    );
  }

  console.log(`apply-windows-launcher-icon: generating icon.ico from ${source}`);
  const result = spawnSync(
    "bun",
    [path.join(rootDir, "scripts/prepare-app-icons.mjs"), source],
    { cwd: rootDir, stdio: "inherit", env: process.env },
  );

  if (result.status !== 0 || !existsSync(iconPath)) {
    throw new Error("apply-windows-launcher-icon: failed to generate assets/icon.ico");
  }

  return iconPath;
}

/**
 * Embed the Farm Control icon into Windows launcher binaries.
 * Electrobun's built-in rcedit step often fails in CI (see electrobun#429).
 */
export async function applyWindowsLauncherIcon(appDir) {
  if (process.platform !== "win32") {
    console.log("apply-windows-launcher-icon: skipped (not Windows)");
    return;
  }

  const iconPath = ensureIconIco();
  const binDir = path.join(appDir, "bin");
  if (!existsSync(binDir)) {
    throw new Error(`apply-windows-launcher-icon: bin directory not found: ${binDir}`);
  }

  const rcedit = (await import("rcedit")).default;
  let patched = 0;

  for (const fileName of WINDOWS_BIN_FILES) {
    const exePath = path.join(binDir, fileName);
    if (!existsSync(exePath)) {
      continue;
    }

    console.log(`apply-windows-launcher-icon: embedding icon into ${exePath}`);
    try {
      await rcedit(exePath, { icon: iconPath });
      patched += 1;
    } catch (error) {
      const message = error instanceof Error ? error.message : String(error);
      throw new Error(
        `apply-windows-launcher-icon: failed to embed icon into ${fileName}: ${message}`,
      );
    }
  }

  if (patched === 0) {
    throw new Error(
      `apply-windows-launcher-icon: no launcher binaries found in ${binDir}`,
    );
  }
}