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

const root = path.resolve(import.meta.dir, "..");
const krita = path.join(root, "krita");
const patchDir = path.join(root, "krita-patches");
const patchFile = path.join(patchDir, "xiaomi-eink.patch");
// Keep generated patches limited to this project. The nested Krita checkout may carry
// line-ending or formatter changes that are not part of the E Ink product patch.
const patchPaths = [
	"CMakeLists.txt",
	"libs/ui/KisApplication.cpp",
	"libs/ui/KisMainWindow.cpp",
	"libs/ui/thememanager.cpp",
	"packaging/android/apk/AndroidManifest.xml",
	"packaging/android/apk/build.gradle",
	"packaging/android/apk/proguard-rules.pro",
	"packaging/android/apk/src/org/krita/android/MainActivity.java",
	"plugins/CMakeLists.txt",
	"plugins/dockers/CMakeLists.txt",
	"plugins/filters/CMakeLists.txt",
	"plugins/impex/CMakeLists.txt",
	"plugins/paintops/CMakeLists.txt",
	"plugins/tools/CMakeLists.txt",
];
const untrackedPatchPaths = [
	"EINK_SLIM.md",
	"packaging/android/apk/.gitignore",
	"packaging/android/apk/settings.gradle",
	"packaging/android/apk/lib/arm64-v8a/libfakeRKEpdUtils.so",
	"packaging/android/apk/src/com/moan/fakerkepdlib/EpdUtil.java",
	"packaging/android/apk/src/org/krita/android/XiaomiEinkController.java",
	"plugins/dockers/einkmonochromeselector/CMakeLists.txt",
	"plugins/dockers/einkmonochromeselector/einkmonochromeselector.cpp",
	"plugins/dockers/einkmonochromeselector/krita_einkmonochromeselector.json",
	"plugins/extensions/einksync/CMakeLists.txt",
	"plugins/extensions/einksync/EinkSyncPlugin.action",
	"plugins/extensions/einksync/EinkSyncPlugin.cpp",
	"plugins/extensions/einksync/kritaeinksync.json",
];

function git(args: string[], allowDifference = false): string {
	const result = spawnSync("git", ["-C", krita, ...args], {
		encoding: "utf8",
		maxBuffer: 128 * 1024 * 1024,
	});
	if (result.error) throw result.error;
	if (result.status !== 0 && !(allowDifference && result.status === 1)) {
		throw new Error(result.stderr || `git ${args.join(" ")} failed`);
	}
	return result.stdout;
}

function generate(): void {
	fs.mkdirSync(patchDir, { recursive: true });
	let output = git([
		"diff",
		"--binary",
		"--ignore-space-at-eol",
		"--",
		...patchPaths,
	]);
	const available = new Set(
		git(["ls-files", "--others", "--exclude-standard"])
			.split("\n")
			.filter(Boolean),
	);
	const untracked = untrackedPatchPaths.filter((file) => available.has(file));
	for (const file of untracked) {
		output += git(
			["diff", "--no-index", "--binary", "--", "/dev/null", file],
			true,
		);
	}
	if (!output.trim()) throw new Error("Krita has no changes to package");
	fs.writeFileSync(patchFile, output);
	console.log(`[ok] Generated ${patchFile} with ${untracked.length} new files`);
}

function apply(): void {
	if (!fs.existsSync(path.join(krita, ".git")))
		throw new Error("Initialize the Krita submodule first");
	if (!fs.existsSync(patchFile)) throw new Error(`Missing ${patchFile}`);
	const applyArgs = ["apply", "--ignore-space-change", "--recount"];
	const check = spawnSync(
		"git",
		["-C", krita, ...applyArgs, "--check", patchFile],
		{
			encoding: "utf8",
		},
	);
	if (check.status === 0) {
		git([...applyArgs, "--whitespace=nowarn", patchFile]);
		console.log("[ok] Applied E Ink Krita patch set");
		return;
	}
	const reverse = spawnSync(
		"git",
		["-C", krita, ...applyArgs, "--reverse", "--check", patchFile],
		{ encoding: "utf8" },
	);
	if (reverse.status === 0) {
		console.log("[ok] E Ink Krita patch set is already applied");
		return;
	}
	throw new Error(`Patch does not apply cleanly\n${check.stderr}`);
}

if (process.argv.includes("--generate")) generate();
else apply();