/**
 * CI Metadata for LangSmith experiments.
 *
 * Distinguishes CI runs from local development runs and tracks provenance
 * of automated evaluation results.
 *
 * Note: git info (commit SHA, branch) is tracked by LangSmith automatically
 * via LANGSMITH_REVISION_ID and LANGSMITH_BRANCH env vars — set them in the
 * CI workflow and the SDK picks them up.
 */

import { execSync } from 'node:child_process';

export interface CIMetadata {
	source: 'ci' | 'local';
	/** GitHub Actions event that triggered this run (e.g., 'pull_request', 'merge_group', 'workflow_dispatch') */
	trigger?: string;
	/** GitHub Actions run ID for linking back to the workflow run */
	runId?: string;
}

export function buildCIMetadata(): CIMetadata {
	const isCI = process.env.GITHUB_ACTIONS === 'true';

	if (!isCI) {
		return { source: 'local' };
	}

	return {
		source: 'ci',
		trigger: process.env.GITHUB_EVENT_NAME,
		runId: process.env.GITHUB_RUN_ID,
	};
}

/**
 * Compute an informative experiment name prefix from branch and commit info.
 * Falls back to a generic name if no git context is available.
 *
 * - CI: `ci-{branch}-{short-sha}` from GitHub Actions env vars
 * - Local: `local-{branch}-{short-sha}[-dirty]` from git, dirty suffix if there are uncommitted changes
 * - Fallback: `instance-ai-workflow-evals`
 *
 * LangSmith appends its own random suffix, so this doesn't need to be unique.
 */
export function computeExperimentPrefix(): string {
	const ciName = computeCIExperimentName();
	if (ciName) return ciName;

	const localName = computeLocalExperimentName();
	if (localName) return localName;

	return 'instance-ai-workflow-evals';
}

function computeCIExperimentName(): string | undefined {
	if (process.env.GITHUB_ACTIONS !== 'true') return undefined;

	const branch =
		process.env.LANGSMITH_BRANCH ?? process.env.GITHUB_HEAD_REF ?? process.env.GITHUB_REF_NAME;
	const sha = process.env.GITHUB_SHA;
	if (!branch || !sha) return undefined;

	return sanitize(`ci-${branch}-${sha.slice(0, 7)}`);
}

function computeLocalExperimentName(): string | undefined {
	try {
		const run = (cmd: string): string =>
			execSync(cmd, { encoding: 'utf8', stdio: ['pipe', 'pipe', 'ignore'] }).trim();

		const branch = run('git rev-parse --abbrev-ref HEAD');
		const sha = run('git rev-parse --short HEAD');
		const dirty = run('git status --porcelain').length > 0 ? '-dirty' : '';
		return sanitize(`local-${branch}-${sha}${dirty}`);
	} catch {
		return undefined;
	}
}

function sanitize(name: string): string {
	return name.replace(/[^a-zA-Z0-9_.-]/g, '_').replace(/_{2,}/g, '_');
}