import { execFileSync, execSync } from "node:child_process";
import { createWriteStream, existsSync, rmSync } from "node:fs";
import { chmod, cp, mkdir, readdir, readFile, rm, stat, writeFile } from "node:fs/promises";
import { get as httpsGet } from "node:https";
import path from "node:path";

import {
	configureWithWindowsCmakeGenerator,
	WINDOWS_VISUAL_STUDIO_INSTALL_DIRS,
} from "./windows-cmake-generators.mjs";

const projectRoot = process.cwd();
const whisperVersion = "v1.8.4";
const nativeRoot = path.join(projectRoot, "electron", "native");
const cacheRoot = path.join(projectRoot, ".tmp", "whisper-runtime");
const archivePath = path.join(cacheRoot, `${whisperVersion}.tar.gz`);
const extractRoot = path.join(cacheRoot, `src-${whisperVersion}`);

function getHostArch() {
	return process.arch === "arm64" ? "arm64" : "x64";
}

function getNativeArchTag(platform, arch) {
	if (platform === "darwin") {
		return arch === "arm64" ? "darwin-arm64" : "darwin-x64";
	}

	if (platform === "win32") {
		return arch === "arm64" ? "win32-arm64" : "win32-x64";
	}

	if (platform === "linux") {
		return arch === "arm64" ? "linux-arm64" : "linux-x64";
	}

	throw new Error(`[build-whisper-runtime] Unsupported platform: ${platform}/${arch}`);
}

function getRequestedArchitectures(platform) {
	const hostArch = getHostArch();
	const configured = process.env.WHISPER_RUNTIME_ARCHS?.trim();

	if (!configured) {
		return [hostArch];
	}

	if (configured === "all") {
		return ["arm64", "x64"];
	}

	const supported = new Set(["arm64", "x64"]);
	const requested = configured
		.split(",")
		.map((entry) => entry.trim())
		.filter(Boolean);

	if (requested.length === 0) {
		return [hostArch];
	}

	const invalid = requested.filter((arch) => !supported.has(arch));
	if (invalid.length > 0) {
		throw new Error(
			`[build-whisper-runtime] Unsupported ${platform} target architecture request: ${invalid.join(", ")}`,
		);
	}

	return [...new Set(requested)];
}

function createDarwinTarget(arch) {
	const targetArch = arch === "arm64" ? "arm64" : "x64";
	const isCrossCompile = targetArch !== getHostArch();
	const configureArgs = [
		"-DCMAKE_BUILD_TYPE=Release",
		`-DCMAKE_OSX_ARCHITECTURES=${targetArch === "arm64" ? "arm64" : "x86_64"}`,
	];

	if (isCrossCompile) {
		configureArgs.push("-DGGML_NATIVE=OFF");
	}

	return {
		platform: "darwin",
		arch: targetArch,
		archTag: getNativeArchTag("darwin", targetArch),
		buildRoot: path.join(cacheRoot, `build-darwin-${targetArch}`),
		outputDir: path.join(nativeRoot, "bin", getNativeArchTag("darwin", targetArch)),
		configureArgs,
	};
}

function getTargetConfigs() {
	if (process.platform === "darwin") {
		return getRequestedArchitectures("darwin").map((arch) => createDarwinTarget(arch));
	}

	const arch = getHostArch();
	const archTag = getNativeArchTag(process.platform, arch);

	if (process.platform === "win32") {
		return [
			{
				platform: "win32",
				arch,
				archTag,
				buildRoot: path.join(cacheRoot, `build-${archTag}`),
				outputDir: path.join(nativeRoot, "bin", archTag),
				configureArgs: ["-A", arch === "arm64" ? "ARM64" : "x64"],
			},
		];
	}

	if (process.platform === "linux") {
		return [
			{
				platform: "linux",
				arch,
				archTag,
				buildRoot: path.join(cacheRoot, `build-${archTag}`),
				outputDir: path.join(nativeRoot, "bin", archTag),
				configureArgs: ["-DCMAKE_BUILD_TYPE=Release"],
			},
		];
	}

	throw new Error(
		`[build-whisper-runtime] Unsupported platform: ${process.platform}/${process.arch}`,
	);
}

function getSourceArchiveUrl() {
	return `https://github.com/ggml-org/whisper.cpp/archive/refs/tags/${whisperVersion}.tar.gz`;
}

function findCmake() {
	try {
		execSync("cmake --version", { stdio: "pipe" });
		return "cmake";
	} catch {
		// not on PATH
	}

	if (process.platform === "win32") {
		const vsEditions = ["Community", "Professional", "Enterprise", "BuildTools"];
		for (const version of WINDOWS_VISUAL_STUDIO_INSTALL_DIRS) {
			for (const edition of vsEditions) {
				const cmakePath = path.join(
					"C:",
					"Program Files",
					"Microsoft Visual Studio",
					version,
					edition,
					"Common7",
					"IDE",
					"CommonExtensions",
					"Microsoft",
					"CMake",
					"CMake",
					"bin",
					"cmake.exe",
				);
				if (existsSync(cmakePath)) {
					return cmakePath;
				}
			}
		}
	}

	return null;
}

function ensureTarAvailable() {
	try {
		execSync("tar --version", { stdio: "pipe" });
	} catch {
		throw new Error("[build-whisper-runtime] tar is required to unpack whisper.cpp sources.");
	}
}

async function downloadFile(url, destinationPath) {
	await mkdir(path.dirname(destinationPath), { recursive: true });

	await new Promise((resolve, reject) => {
		const request = (currentUrl, redirectCount = 0) => {
			const req = httpsGet(currentUrl, (response) => {
				const statusCode = response.statusCode ?? 0;
				const location = response.headers.location;

				if (statusCode >= 300 && statusCode < 400 && location) {
					response.resume();
					if (redirectCount >= 5) {
						reject(
							new Error(
								"[build-whisper-runtime] Too many redirects while downloading whisper.cpp source.",
							),
						);
						return;
					}
					request(new URL(location, currentUrl).toString(), redirectCount + 1);
					return;
				}

				if (statusCode < 200 || statusCode >= 300) {
					response.resume();
					reject(
						new Error(
							`[build-whisper-runtime] Failed to download whisper.cpp source: HTTP ${statusCode}`,
						),
					);
					return;
				}

				const fileStream = createWriteStream(destinationPath);
				fileStream.on("finish", resolve);
				fileStream.on("error", reject);
				response.on("error", reject);
				response.pipe(fileStream);
			});

			req.on("error", reject);
		};

		request(url);
	});
}

async function ensureSourceTree() {
	const extractedSourceDir = path.join(
		extractRoot,
		`whisper.cpp-${whisperVersion.replace(/^v/, "")}`,
	);
	if (existsSync(path.join(extractedSourceDir, "CMakeLists.txt"))) {
		return extractedSourceDir;
	}

	await rm(extractRoot, { recursive: true, force: true });
	await mkdir(extractRoot, { recursive: true });

	if (!existsSync(archivePath)) {
		console.log(`[build-whisper-runtime] Downloading whisper.cpp ${whisperVersion} source...`);
		await downloadFile(getSourceArchiveUrl(), archivePath);
	}

	ensureTarAvailable();
	execFileSync("tar", ["-xzf", archivePath, "-C", extractRoot], { stdio: "inherit" });

	if (!existsSync(path.join(extractedSourceDir, "CMakeLists.txt"))) {
		throw new Error(
			`[build-whisper-runtime] Extracted whisper.cpp source not found at ${extractedSourceDir}`,
		);
	}

	return extractedSourceDir;
}

async function shouldSkipBuild(target) {
	const manifestPath = path.join(target.outputDir, "whisper-runtime.json");
	if (!existsSync(manifestPath)) {
		return false;
	}

	try {
		const manifest = JSON.parse(await readFile(manifestPath, "utf8"));
		const binaryName = target.platform === "win32" ? "whisper-cli.exe" : "whisper-cli";
		const binaryPath = path.join(target.outputDir, binaryName);
		return (
			manifest.version === whisperVersion &&
			manifest.arch === target.arch &&
			existsSync(binaryPath)
		);
	} catch {
		return false;
	}
}

function getConfigureArgs(sourceDir, target, generator, toolset) {
	const args = [
		"-S",
		sourceDir,
		"-B",
		target.buildRoot,
		"-DWHISPER_BUILD_TESTS=OFF",
		"-DWHISPER_BUILD_SERVER=OFF",
		"-DBUILD_SHARED_LIBS=OFF",
		...(generator ? ["-G", generator] : []),
		...(toolset ? ["-T", toolset] : []),
		...target.configureArgs,
	];

	return args;
}

function getBuildArgs(target) {
	const args = ["--build", target.buildRoot, "--config", "Release"];

	if (target.platform !== "win32") {
		args.push("--parallel");
	}

	return args;
}

async function findRuntimeArtifacts(target) {
	const candidateDirs =
		target.platform === "win32"
			? [path.join(target.buildRoot, "bin", "Release"), path.join(target.buildRoot, "bin")]
			: [path.join(target.buildRoot, "bin")];

	for (const candidateDir of candidateDirs) {
		if (!existsSync(candidateDir)) {
			continue;
		}

		const entries = await readdir(candidateDir);
		const runtimeEntries = entries.filter((entry) =>
			/^(whisper|ggml|libwhisper|libggml)/i.test(entry),
		);
		if (runtimeEntries.length > 0) {
			return {
				candidateDir,
				runtimeEntries,
			};
		}
	}

	throw new Error("[build-whisper-runtime] Built whisper runtime artifacts were not found.");
}

async function stageRuntimeArtifacts(target, candidateDir, runtimeEntries) {
	await mkdir(target.outputDir, { recursive: true });

	for (const entry of runtimeEntries) {
		const sourcePath = path.join(candidateDir, entry);
		const destinationPath = path.join(target.outputDir, entry);
		const entryStats = await stat(sourcePath);

		if (entryStats.isDirectory()) {
			await rm(destinationPath, { recursive: true, force: true });
			await cp(sourcePath, destinationPath, { recursive: true });
			continue;
		}

		await cp(sourcePath, destinationPath, { force: true });
		if (target.platform !== "win32") {
			await chmod(destinationPath, 0o755).catch(() => undefined);
		}
	}

	const manifestPath = path.join(target.outputDir, "whisper-runtime.json");
	await writeFile(
		manifestPath,
		JSON.stringify(
			{
				version: whisperVersion,
				platform: target.platform,
				arch: target.arch,
				binary: target.platform === "win32" ? "whisper-cli.exe" : "whisper-cli",
			},
			null,
			2,
		),
		"utf8",
	);
}

async function main() {
	const targets = getTargetConfigs();
	const cmake = findCmake();

	if (!cmake) {
		// Soft-fail only when this script runs as part of `npm install`/`npm ci`,
		// in CI, or when the developer explicitly opted in. Direct invocations
		// (e.g. via `npm run build`, `build:win`, `build:mac`, `build:linux`)
		// must still fail loudly so we never ship a release build that is
		// missing the whisper runtime and silently ships broken auto-captions.
		const isPostinstall = process.env.npm_lifecycle_event === "postinstall";
		const isCI = process.env.CI === "true";
		const allowMissing = process.env.WHISPER_RUNTIME_ALLOW_MISSING === "1";
		const softFailAllowed = isPostinstall || isCI || allowMissing;

		const skipChecks = await Promise.all(targets.map((target) => shouldSkipBuild(target)));
		const allTargetsStaged = skipChecks.every(Boolean);

		if (allTargetsStaged) {
			console.log(
				"[build-whisper-runtime] CMake not found; using bundled whisper runtime artifacts.",
			);
			return;
		}

		const missing = targets
			.filter((_target, index) => !skipChecks[index])
			.map((target) => target.archTag)
			.join(", ");

		if (softFailAllowed) {
			console.warn(
				`[build-whisper-runtime] CMake not found and no bundled runtime is staged for: ${missing}. ` +
					"Auto-caption features that rely on whisper.cpp will be unavailable until you install CMake " +
					"and rerun `npm run build:whisper-runtime`.",
			);
			return;
		}

		throw new Error(
			`[build-whisper-runtime] CMake is required to stage the whisper runtime for: ${missing}. ` +
				"Install CMake and retry, or set WHISPER_RUNTIME_ALLOW_MISSING=1 to build without auto-caption support.",
		);
	}

	const sourceDir = await ensureSourceTree();

	console.log(
		`[build-whisper-runtime] Target architectures for ${process.platform}: ${targets.map((target) => target.archTag).join(", ")}`,
	);

	for (const target of targets) {
		if (await shouldSkipBuild(target)) {
			console.log(
				`[build-whisper-runtime] Whisper runtime ${whisperVersion} already staged for ${target.archTag}.`,
			);
			continue;
		}

		await mkdir(target.buildRoot, { recursive: true });

		console.log(
			`[build-whisper-runtime] Configuring whisper.cpp ${whisperVersion} for ${target.archTag}...`,
		);
		if (target.platform === "win32") {
			configureWithWindowsCmakeGenerator({
				prefix: "build-whisper-runtime",
				clearCache: () => {
					rmSync(path.join(target.buildRoot, "CMakeCache.txt"), { force: true });
					rmSync(path.join(target.buildRoot, "CMakeFiles"), {
						recursive: true,
						force: true,
					});
				},
				configure: (generator, toolset) =>
					execFileSync(cmake, getConfigureArgs(sourceDir, target, generator, toolset), {
						stdio: "inherit",
						timeout: 300000,
					}),
			});
		} else {
			execFileSync(cmake, getConfigureArgs(sourceDir, target), {
				stdio: "inherit",
				timeout: 300000,
			});
		}

		console.log(
			`[build-whisper-runtime] Building bundled whisper runtime for ${target.archTag}...`,
		);
		execFileSync(cmake, getBuildArgs(target), { stdio: "inherit", timeout: 900000 });

		const { candidateDir, runtimeEntries } = await findRuntimeArtifacts(target);
		await stageRuntimeArtifacts(target, candidateDir, runtimeEntries);
		console.log(`[build-whisper-runtime] Staged whisper runtime -> ${target.outputDir}`);
	}
}

await main();