import { NextResponse } from "next/server";
import {
  createLanguage,
  listLanguages,
  listTranslations,
} from "@/lib/db/languages";
import { computeCompleteness, currentTemplateHash } from "@/lib/i18n/template";
import { ForbiddenError, requireRole, UnauthorizedError } from "@/lib/auth/session";
import { isSameOrigin } from "@/lib/origin";

// Sprachverwaltung (nur Admin) – gleiches Auth-/CSRF-Muster wie
// app/api/admin/users/route.ts.

async function requireAdmin(request: Request) {
  if (!isSameOrigin(request)) throw new ForbiddenError();
  return requireRole(["admin"]);
}

function errorResponse(err: unknown) {
  if (err instanceof UnauthorizedError || err instanceof ForbiddenError) {
    return NextResponse.json({ error: "Nicht berechtigt." }, { status: 403 });
  }
  return null;
}

const CODE_PATTERN = /^[a-z]{2,5}$/;

export async function GET(request: Request) {
  try {
    await requireAdmin(request);
  } catch (err) {
    const res = errorResponse(err);
    if (res) return res;
    throw err;
  }

  const languages = await listLanguages();
  const hash = currentTemplateHash();

  const items = await Promise.all(
    languages.map(async (lang) => {
      if (lang.is_base) {
        return {
          code: lang.code,
          label: lang.label,
          is_base: true,
          active: lang.active,
          percent: 100,
          outdated: false,
          missingCount: 0,
        };
      }
      const rows = await listTranslations(lang.code);
      const translated = Object.fromEntries(rows.map((r) => [r.key, r.value]));
      const completeness = computeCompleteness(translated);
      return {
        code: lang.code,
        label: lang.label,
        is_base: false,
        active: lang.active,
        percent: completeness.percent,
        outdated: lang.template_version !== hash,
        missingCount: completeness.missingKeys.length,
      };
    })
  );

  return NextResponse.json(items);
}

export async function POST(request: Request) {
  try {
    await requireAdmin(request);
  } catch (err) {
    const res = errorResponse(err);
    if (res) return res;
    throw err;
  }

  const body = await request.json().catch(() => null);
  const code = String(body?.code ?? "").trim().toLowerCase();
  const label = String(body?.label ?? "").trim();
  if (!CODE_PATTERN.test(code) || !label) {
    return NextResponse.json({ error: "invalid_input" }, { status: 400 });
  }

  try {
    const language = await createLanguage(code, label);
    return NextResponse.json(language, { status: 201 });
  } catch (err) {
    if (err instanceof Error && /duplicate key/i.test(err.message)) {
      return NextResponse.json({ error: "duplicate_code" }, { status: 409 });
    }
    throw err;
  }
}