import { MessageDirection } from "@prisma/client";
import webpush from "web-push";

import { getDeviceName, truncateText } from "@/lib/panel-format";
import { prisma } from "@/lib/prisma";

type SerializablePushSubscription = {
  endpoint: string;
  expirationTime?: number | null;
  keys?: {
    p256dh?: string;
    auth?: string;
  };
};

const APP_BASE_URL = (
  process.env.NEXT_PUBLIC_APP_URL || "https://digital-human.xn--876a.net"
).replace(/\/+$/, "");

let vapidReady = false;

function hasPushConfiguration() {
  return Boolean(
    process.env.NEXT_PUBLIC_VAPID_PUBLIC_KEY &&
      process.env.VAPID_PRIVATE_KEY &&
      process.env.VAPID_SUBJECT,
  );
}

function ensureVapidDetails() {
  if (!hasPushConfiguration()) {
    throw new Error("VAPID 配置尚未完成，暂时不能发送推送通知。");
  }

  if (vapidReady) {
    return;
  }

  webpush.setVapidDetails(
    process.env.VAPID_SUBJECT!,
    process.env.NEXT_PUBLIC_VAPID_PUBLIC_KEY!,
    process.env.VAPID_PRIVATE_KEY!,
  );
  vapidReady = true;
}

function normalizeSubscription(input: SerializablePushSubscription) {
  const endpoint = input.endpoint?.trim();
  const p256dh = input.keys?.p256dh?.trim();
  const auth = input.keys?.auth?.trim();

  if (!endpoint || !p256dh || !auth) {
    throw new Error("推送订阅信息不完整。");
  }

  return {
    endpoint,
    p256dh,
    auth,
    expirationTime:
      typeof input.expirationTime === "number"
        ? new Date(input.expirationTime)
        : null,
  };
}

function absoluteUrl(path: string) {
  if (/^https?:\/\//i.test(path)) {
    return path;
  }

  return `${APP_BASE_URL}${path.startsWith("/") ? path : `/${path}`}`;
}

export function getPushPublicKey() {
  return process.env.NEXT_PUBLIC_VAPID_PUBLIC_KEY || "";
}

export function isPushAvailable() {
  return hasPushConfiguration();
}

export async function savePushSubscription(input: {
  caregiverId: string;
  subscription: SerializablePushSubscription;
  userAgent?: string | null;
}) {
  const subscription = normalizeSubscription(input.subscription);

  return prisma.pushSubscription.upsert({
    where: { endpoint: subscription.endpoint },
    update: {
      caregiverId: input.caregiverId,
      p256dh: subscription.p256dh,
      auth: subscription.auth,
      expirationTime: subscription.expirationTime,
      userAgent: input.userAgent?.trim() || null,
    },
    create: {
      caregiverId: input.caregiverId,
      endpoint: subscription.endpoint,
      p256dh: subscription.p256dh,
      auth: subscription.auth,
      expirationTime: subscription.expirationTime,
      userAgent: input.userAgent?.trim() || null,
    },
  });
}

export async function removePushSubscription(input: {
  caregiverId: string;
  endpoint: string;
}) {
  await prisma.pushSubscription.deleteMany({
    where: {
      caregiverId: input.caregiverId,
      endpoint: input.endpoint.trim(),
    },
  });
}

export async function sendIncomingMessagePush(publicId: number) {
  if (!hasPushConfiguration()) {
    return;
  }

  const message = await prisma.familyMessage.findUnique({
    where: { publicId },
    select: {
      publicId: true,
      content: true,
      direction: true,
      elderDeviceId: true,
      elderDevice: {
        select: {
          deviceUuid: true,
          displayName: true,
        },
      },
    },
  });

  if (!message || message.direction !== MessageDirection.ELDER_TO_FAMILY) {
    return;
  }

  const subscriptions = await prisma.pushSubscription.findMany({
    where: {
      caregiver: {
        bindings: {
          some: {
            elderDeviceId: message.elderDeviceId,
          },
        },
      },
    },
  });

  if (subscriptions.length === 0) {
    return;
  }

  ensureVapidDetails();

  const deviceName = getDeviceName(message.elderDevice.displayName);
  const payload = JSON.stringify({
    title: `${deviceName} 发来一条新留言`,
    body: truncateText(message.content, 72),
    url: absoluteUrl(`/messages/${message.publicId}`),
    icon: absoluteUrl("/pwa/icon-192x192.png"),
    badge: absoluteUrl("/pwa/badge-96x96.png"),
    tag: `message-${message.publicId}`,
  });

  await Promise.allSettled(
    subscriptions.map(async (subscription) => {
      try {
        await webpush.sendNotification(
          {
            endpoint: subscription.endpoint,
            expirationTime: subscription.expirationTime?.getTime() || null,
            keys: {
              p256dh: subscription.p256dh,
              auth: subscription.auth,
            },
          },
          payload,
          {
            TTL: 60 * 30,
            urgency: "high",
            topic: `msg-${message.publicId}`,
          },
        );
      } catch (error) {
        const statusCode =
          error && typeof error === "object" && "statusCode" in error
            ? Number((error as { statusCode?: number }).statusCode)
            : 0;

        if (statusCode === 404 || statusCode === 410) {
          await prisma.pushSubscription.deleteMany({
            where: { endpoint: subscription.endpoint },
          });
        }
      }
    }),
  );
}