#!/usr/bin/env bun

/**
 * Stop hook that runs Biome CI on staged/changed files at end of turn.
 * Provides a final quality gate before Claude completes its response.
 *
 * Git-aware: Only checks files that have been modified or staged.
 * Uses `biome ci` (read-only, strict) for project-wide validation.
 *
 * Exit codes:
 * - 0: Success (all files pass or no relevant changes)
 * - 2: Blocking error (lint/format errors found, shown to Claude for follow-up)
 */

import { spawn } from "bun";
import { parseBiomeOutput } from "../mcp-servers/bun-runner/index";
import { BIOME_SUPPORTED_EXTENSIONS } from "./shared/constants";
import { getChangedFiles } from "./shared/git-utils";

function formatDiagnostics(
	summary: ReturnType<typeof parseBiomeOutput>,
): string {
	if (summary.error_count === 0 && summary.warning_count === 0) {
		return "";
	}

	const lines: string[] = [];
	lines.push(
		`${summary.error_count} error(s), ${summary.warning_count} warning(s):`,
	);

	for (const d of summary.diagnostics) {
		lines.push(`  ${d.file}:${d.line} [${d.code}] ${d.message}`);
	}

	return lines.join("\n");
}

async function main() {
	// Get changed files filtered by Biome-supported extensions
	const filesToCheck = await getChangedFiles(BIOME_SUPPORTED_EXTENSIONS);

	if (filesToCheck.length === 0) {
		// No relevant files changed, nothing to check
		process.exit(0);
	}

	// Run biome ci (strict, read-only) on changed files
	const proc = spawn({
		cmd: [
			"bunx",
			"@biomejs/biome",
			"ci",
			"--reporter=json",
			"--no-errors-on-unmatched",
			"--colors=off", // Explicitly disable colors for clean JSON
			...filesToCheck,
		],
		stdout: "pipe",
		stderr: "pipe",
		env: { ...process.env, NO_COLOR: "1", FORCE_COLOR: "0" }, // Also set fallback env vars
	});

	const exitCode = await proc.exited;
	const stdout = await new Response(proc.stdout).text();

	if (exitCode === 0) {
		// All checks passed
		process.exit(0);
	}

	// Parse and report errors
	if (stdout.trim()) {
		const summary = parseBiomeOutput(stdout);
		if (summary.error_count > 0 || summary.warning_count > 0) {
			const diagnostics = formatDiagnostics(summary);
			console.error(
				`Biome CI found issues in ${filesToCheck.length} changed file(s):\n${diagnostics}`,
			);
			console.error('\nRun "biome check --write" to auto-fix safe issues.');
			process.exit(2);
		}
	}

	process.exit(0);
}

main();