import { NextResponse } from "next/server";
import { upsertPushSubscription, removePushSubscription } from "@/lib/push-store";
import { isWebPushConfigured } from "@/lib/push-service";
import { normalizeProvinceName } from "@/lib/provinces";
import { DEFAULT_TEMPERATURE_UNIT, DEFAULT_WIND_SPEED_UNIT, isTemperatureUnit, isWindSpeedUnit } from "@/lib/weather-utils";
import type { Language } from "@/lib/i18n";
import type { BrowserPushSubscription } from "@/types/notifications";
import type { WeatherRegion } from "@/types/weather-region";

export const runtime = "nodejs";

function isBrowserPushSubscription(value: unknown): value is BrowserPushSubscription {
  if (!value || typeof value !== "object") return false;
  const subscription = value as Partial<BrowserPushSubscription>;
  return typeof subscription.endpoint === "string"
    && subscription.endpoint.startsWith("https://")
    && typeof subscription.keys?.p256dh === "string"
    && typeof subscription.keys.auth === "string";
}

export async function POST(request: Request) {
  if (!isWebPushConfigured()) {
    return NextResponse.json({ error: "Web Push is not configured." }, { status: 503 });
  }

  const body = await request.json().catch(() => null) as {
    subscription?: unknown;
    province?: unknown;
    region?: unknown;
    language?: unknown;
    enabled?: unknown;
    morningBriefEnabled?: unknown;
    tomorrowBriefEnabled?: unknown;
    latitude?: unknown;
    longitude?: unknown;
    locationName?: unknown;
    timezone?: unknown;
    countyTeryt?: unknown;
    temperatureUnit?: unknown;
    windSpeedUnit?: unknown;
  } | null;
  const subscription = body?.subscription;
  const region: WeatherRegion = body?.region === "GLOBAL" ? "GLOBAL" : "PL";
  const province = normalizeProvinceName(typeof body?.province === "string" ? body.province : null);
  const language: Language = body?.language === "en" ? "en" : "pl";
  const rawTemperatureUnit = body?.temperatureUnit;
  const rawWindSpeedUnit = body?.windSpeedUnit;

  const enabled = body?.enabled !== false && region === "PL";
  if (!isBrowserPushSubscription(subscription) || (enabled && !province)) {
    return NextResponse.json({ error: "Invalid push subscription." }, { status: 400 });
  }

  const now = new Date().toISOString();
  upsertPushSubscription({
    endpoint: subscription.endpoint,
    subscription,
    province,
    region,
    language,
    enabled,
    morningBriefEnabled: body?.morningBriefEnabled === true,
    tomorrowBriefEnabled: body?.tomorrowBriefEnabled === true,
    latitude: typeof body?.latitude === "number" && Number.isFinite(body.latitude) ? body.latitude : null,
    longitude: typeof body?.longitude === "number" && Number.isFinite(body.longitude) ? body.longitude : null,
    locationName: typeof body?.locationName === "string" && body.locationName.trim() ? body.locationName.trim().slice(0, 80) : null,
    timezone: typeof body?.timezone === "string" && body.timezone.trim() ? body.timezone.trim().slice(0, 80) : null,
    countyTeryt: typeof body?.countyTeryt === "string" && /^\d{4}$/.test(body.countyTeryt) ? body.countyTeryt : null,
    temperatureUnit: isTemperatureUnit(rawTemperatureUnit) ? rawTemperatureUnit : DEFAULT_TEMPERATURE_UNIT,
    windSpeedUnit: isWindSpeedUnit(rawWindSpeedUnit) ? rawWindSpeedUnit : DEFAULT_WIND_SPEED_UNIT,
    createdAt: now,
    updatedAt: now,
  });

  return NextResponse.json({ ok: true });
}

export async function DELETE(request: Request) {
  const body = await request.json().catch(() => null) as { endpoint?: unknown } | null;
  if (typeof body?.endpoint !== "string" || !body.endpoint) {
    return NextResponse.json({ error: "Invalid push subscription endpoint." }, { status: 400 });
  }
  removePushSubscription(body.endpoint);
  return NextResponse.json({ ok: true });
}