import { execFileSync } from "node:child_process";
import type { GitInfo } from "./types.js";

export function getGitInfo(cwd: string): GitInfo {
	const branch = git(cwd, ["branch", "--show-current"]);
	if (!branch) return { branch: null, dirty: false, ahead: 0, behind: 0 };
	const porcelain = git(cwd, ["status", "--porcelain=v1", "--branch"]) ?? "";
	const lines = porcelain.split("\n").filter(Boolean);
	let ahead = 0;
	let behind = 0;
	const first = lines[0] ?? "";
	const aheadMatch = first.match(/ahead (\d+)/);
	const behindMatch = first.match(/behind (\d+)/);
	if (aheadMatch) ahead = Number(aheadMatch[1]);
	if (behindMatch) behind = Number(behindMatch[1]);
	const fileStats = { modified: 0, added: 0, deleted: 0, untracked: 0 };
	for (const line of lines.slice(1)) {
		const xy = line.slice(0, 2);
		if (xy.includes("?")) fileStats.untracked += 1;
		if (xy.includes("M")) fileStats.modified += 1;
		if (xy.includes("A")) fileStats.added += 1;
		if (xy.includes("D")) fileStats.deleted += 1;
	}
	return { branch, dirty: lines.length > 1, ahead, behind, fileStats };
}

function git(cwd: string, args: string[]): string | null {
	try {
		return execFileSync("git", args, {
			cwd,
			encoding: "utf8",
			stdio: ["ignore", "pipe", "ignore"],
			timeout: 300,
		}).trim();
	} catch {
		return null;
	}
}