import type { ScopedInstruction } from "./instructions.ts";

export type ReportLanguage = "en" | "zh-CN";

function countMatches(value: string, pattern: RegExp): number {
	return value.match(pattern)?.length ?? 0;
}

export function detectReportLanguage(
	instructions: ScopedInstruction[],
): ReportLanguage {
	const root = instructions.find(
		(instruction) => instruction.path === "AGENTS.md",
	);
	const content =
		root?.content ?? instructions.map((item) => item.content).join("\n");
	const han = countMatches(content, /\p{Script=Han}/gu);
	const latin = countMatches(content, /\p{Script=Latin}/gu);
	const kana = countMatches(
		content,
		/[\p{Script=Hiragana}\p{Script=Katakana}]/gu,
	);
	const hangul = countMatches(content, /\p{Script=Hangul}/gu);
	if (kana > 0 || hangul > 0) return "en";
	return han >= 8 && han / Math.max(han + latin, 1) >= 0.2 ? "zh-CN" : "en";
}