import { NextRequest, NextResponse } from "next/server";
import {
  getApiUrlFromRequest,
  getPaymentConfig,
  getPocketBaseConfig,
} from "@/config/services.config";
import {
  ensureSiteVipForUser,
  findAnonymousUserIdForUser,
  findVipEmailLinkByEmail,
  getAdminToken,
  hasVipByUserId,
  isAnonymousUserId,
  upsertVipEmailLink,
} from "@/app/api/vip/_helpers";

type PBAuthRecord = {
  id: string;
  email?: string;
};

type PayjsVipEmailResult = {
  vip: boolean;
  effectiveUserId?: string;
  anonymousUserId?: string;
};

type RecoveryResult = {
  vip: boolean;
  matchedUserId?: string;
  anonymousUserId?: string;
  source?: string;
};

function resolvePayApiUrl(request: NextRequest): string {
  const payConfig = getPaymentConfig();
  const hostHeader = request.headers.get("host") || request.headers.get("x-forwarded-host");
  return (
    (hostHeader ? getApiUrlFromRequest(hostHeader) : null) ||
    payConfig.apiUrl
  ).replace(/\/$/, "");
}

async function checkVipByEmailFromPayjsapi(
  request: NextRequest,
  email: string,
  password: string,
  userId?: string
): Promise<PayjsVipEmailResult | null> {
  try {
    const apiUrl = resolvePayApiUrl(request);
    const res = await fetch(`${apiUrl}/nomadvip/check_vip_by_email`, {
      method: "POST",
      headers: { "Content-Type": "application/json" },
      body: JSON.stringify({
        email,
        password,
        ...(userId ? { user_id: userId } : {}),
      }),
      cache: "no-store",
      signal: AbortSignal.timeout(15000),
    });
    if (!res.ok) {
      return null;
    }

    const data = await res.json().catch(() => ({}));
    if (!data?.vip) {
      return null;
    }

    return {
      vip: true,
      effectiveUserId:
        typeof data?.effectiveUserId === "string"
          ? data.effectiveUserId.trim()
          : undefined,
      anonymousUserId:
        typeof data?.anonymousUserId === "string"
          ? data.anonymousUserId.trim()
          : undefined,
    };
  } catch (error) {
    console.log("[check-by-email] payjsapi request failed:", error);
    return null;
  }
}

async function loginPocketBaseUser(
  email: string,
  password: string
): Promise<{ token: string; record: PBAuthRecord }> {
  const pb = getPocketBaseConfig();
  const res = await fetch(`${pb.url}/api/collections/users/auth-with-password`, {
    method: "POST",
    headers: { "Content-Type": "application/json" },
    body: JSON.stringify({ identity: email, password }),
    cache: "no-store",
  });

  if (!res.ok) {
    const error = await res.json().catch(() => ({}));
    throw new Error(error?.message || "邮箱或密码错误");
  }

  const data = await res.json().catch(() => ({}));
  if (!data?.token || !data?.record?.id) {
    throw new Error("登录失败");
  }

  return {
    token: data.token,
    record: data.record,
  };
}

async function resolveRecovery(
  adminToken: string,
  email: string,
  pbUserId: string,
  requestedAnonymousUserId?: string,
  payjsResult?: PayjsVipEmailResult | null
): Promise<RecoveryResult> {
  if (
    isAnonymousUserId(requestedAnonymousUserId) &&
    (await hasVipByUserId(adminToken, requestedAnonymousUserId))
  ) {
    return {
      vip: true,
      matchedUserId: requestedAnonymousUserId,
      anonymousUserId: requestedAnonymousUserId,
      source: "request_user_id",
    };
  }

  const linkRecord = await findVipEmailLinkByEmail(adminToken, email);
  const linkedAnonymousUserId =
    typeof linkRecord?.anonymous_user_id === "string"
      ? linkRecord.anonymous_user_id.trim()
      : (await findAnonymousUserIdForUser(adminToken, pbUserId)) ?? "";
  const linkedIds = Array.from(
    new Set(
      [
        linkedAnonymousUserId,
        typeof linkRecord?.user_id === "string" ? linkRecord.user_id.trim() : "",
        pbUserId,
      ].filter(Boolean)
    )
  );

  for (const linkedId of linkedIds) {
    if (!(await hasVipByUserId(adminToken, linkedId))) {
      continue;
    }

    return {
      vip: true,
      matchedUserId: linkedId,
      anonymousUserId: isAnonymousUserId(linkedAnonymousUserId)
        ? linkedAnonymousUserId
        : isAnonymousUserId(linkedId)
          ? linkedId
          : undefined,
      source: "vip_email_link",
    };
  }

  if (await hasVipByUserId(adminToken, pbUserId)) {
    return {
      vip: true,
      matchedUserId: pbUserId,
      source: "pb_user_id",
    };
  }

  const payjsCandidates = Array.from(
    new Set(
      [
        typeof payjsResult?.effectiveUserId === "string"
          ? payjsResult.effectiveUserId.trim()
          : "",
        typeof payjsResult?.anonymousUserId === "string"
          ? payjsResult.anonymousUserId.trim()
          : "",
      ].filter(Boolean)
    )
  );

  for (const candidate of payjsCandidates) {
    if (!(await hasVipByUserId(adminToken, candidate))) {
      continue;
    }

    return {
      vip: true,
      matchedUserId: candidate,
      anonymousUserId: isAnonymousUserId(candidate)
        ? candidate
        : typeof payjsResult?.anonymousUserId === "string" &&
            isAnonymousUserId(payjsResult.anonymousUserId.trim())
          ? payjsResult.anonymousUserId.trim()
          : undefined,
      source: "payjsapi",
    };
  }

  return { vip: false };
}

export async function POST(request: NextRequest) {
  const body = await request.json().catch(() => ({}));
  const email = String(body?.email ?? "").trim().toLowerCase();
  const password = String(body?.password ?? "").trim();
  const requestedAnonymousUserId = String(
    body?.user_id ?? body?.anonymousUserId ?? ""
  ).trim();

  console.log(
    "[check-by-email] request email=%s user_id=%s",
    email || "(empty)",
    requestedAnonymousUserId || "(empty)"
  );

  if (!email || !password) {
    return NextResponse.json(
      { ok: false, vip: false, error: "请填写邮箱和密码" },
      { status: 400 }
    );
  }

  try {
    const authData = await loginPocketBaseUser(email, password);
    const adminToken = await getAdminToken();
    if (!adminToken) {
      return NextResponse.json(
        { ok: false, vip: false, error: "PocketBase 管理员认证失败" },
        { status: 500 }
      );
    }

    let payjsResult: PayjsVipEmailResult | null = null;
    let recovery = await resolveRecovery(
      adminToken,
      email,
      authData.record.id,
      requestedAnonymousUserId || undefined,
      payjsResult
    );

    if (!recovery.vip) {
      payjsResult = await checkVipByEmailFromPayjsapi(
        request,
        email,
        password,
        requestedAnonymousUserId || undefined
      );
      recovery = await resolveRecovery(
        adminToken,
        email,
        authData.record.id,
        requestedAnonymousUserId || undefined,
        payjsResult
      );
    }

    if (!recovery.vip) {
      console.log(
        "[check-by-email] no-vip email=%s pbUserId=%s",
        email,
        authData.record.id
      );
      return NextResponse.json({
        ok: false,
        vip: false,
        error:
          "未找到关联的会员记录，请确认已支付并绑定邮箱；如为历史匿名订单，可填写支付时的 user_id 再登录",
      });
    }

    const fallbackAnonymousUserId = isAnonymousUserId(requestedAnonymousUserId)
      ? requestedAnonymousUserId
      : (await findAnonymousUserIdForUser(adminToken, authData.record.id)) ||
        (typeof payjsResult?.anonymousUserId === "string" &&
        isAnonymousUserId(payjsResult.anonymousUserId.trim())
          ? payjsResult.anonymousUserId.trim()
          : undefined);

    const anonymousUserId =
      recovery.anonymousUserId || fallbackAnonymousUserId;

    if (isAnonymousUserId(anonymousUserId)) {
      await ensureSiteVipForUser(adminToken, anonymousUserId, authData.record.id);
    }

    await upsertVipEmailLink(
      adminToken,
      email,
      authData.record.id,
      anonymousUserId
    );

    console.log(
      "[check-by-email] success source=%s pbUserId=%s anonymousUserId=%s",
      recovery.source ?? "pocketbase",
      authData.record.id,
      anonymousUserId ?? "(none)"
    );

    return NextResponse.json({
      ok: true,
      vip: true,
      token: authData.token,
      record: authData.record,
      effectiveUserId: authData.record.id,
      anonymousUserId: anonymousUserId ?? null,
      memosAccount: anonymousUserId ?? null,
      source: recovery.source ?? "pocketbase",
    });
  } catch (error) {
    const message = error instanceof Error ? error.message : "登录失败";
    const status = message.includes("密码") || message.includes("邮箱") ? 401 : 500;
    return NextResponse.json(
      { ok: false, vip: false, error: message },
      { status }
    );
  }
}