/**
 * Version utility for sapling CLI.
 * Shared by upgrade and doctor commands.
 */

import { execSync } from "node:child_process";
import { readFileSync } from "node:fs";
import { join } from "node:path";

const PACKAGE_NAME = "@os-eco/sapling-cli";

/**
 * Read the current CLI version from package.json.
 */
export function getCurrentVersion(): string {
	const pkgPath = join(import.meta.dir, "..", "..", "package.json");
	const pkg = JSON.parse(readFileSync(pkgPath, "utf-8")) as { version: string };
	return pkg.version;
}

/**
 * Fetch the latest published version of sapling-cli from npm.
 * Returns null if the registry is unreachable or the command fails.
 */
export function getLatestVersion(): string | null {
	try {
		const result = execSync(`npm view ${PACKAGE_NAME} version`, {
			encoding: "utf-8",
			timeout: 10000,
			stdio: ["pipe", "pipe", "pipe"],
		});
		return result.trim();
	} catch {
		return null;
	}
}

/**
 * Compare two semver strings (major.minor.patch).
 * Returns -1 if a < b, 0 if equal, 1 if a > b.
 */
export function compareSemver(a: string, b: string): -1 | 0 | 1 {
	const partsA = a.split(".").map(Number);
	const partsB = b.split(".").map(Number);

	for (let i = 0; i < 3; i++) {
		const segA = partsA[i] ?? 0;
		const segB = partsB[i] ?? 0;
		if (segA < segB) return -1;
		if (segA > segB) return 1;
	}
	return 0;
}