import { execFileSync } from 'node:child_process';
import { dirname, resolve } from 'node:path';
import { fileURLToPath } from 'node:url';

const repositoryRoot = resolve(dirname(fileURLToPath(import.meta.url)), '..', '..', '..');

type GitCommitReader = () => string;

export type BuildChannel = 'dev' | 'production';

function readGitCommit(): string {
	return execFileSync('git', ['rev-parse', 'HEAD'], {
		cwd: repositoryRoot,
		encoding: 'utf8'
	}).trim();
}

export function resolveBuildCommit(
	env: NodeJS.ProcessEnv = process.env,
	readCommit: GitCommitReader = readGitCommit
): string {
	const override = env.CARTESIUM_COMMIT?.trim();

	if (override) return override;

	try {
		const commit = readCommit().trim();

		return commit || 'unknown';
	} catch {
		return 'unknown';
	}
}

/**
 * Keep the development-server marker separate from the commit value. The
 * commit is also emitted as raw metadata, so adding a suffix to it would make
 * the full-commit tooltip and data attribute unusable for provenance checks.
 */
export function resolveBuildChannel(command: 'build' | 'serve'): BuildChannel {
	return command === 'serve' ? 'dev' : 'production';
}