import { betterAuth } from "better-auth";
import { prismaAdapter } from "better-auth/adapters/prisma";
import { admin, organization } from "better-auth/plugins";
import { nextCookies } from "better-auth/next-js";
import { prisma } from "@/lib/db";
import { sendEmail, emailLayout } from "@/lib/email";

const appUrl = process.env.NEXT_PUBLIC_APP_URL || "http://localhost:3000";

const googleConfigured = !!(process.env.GOOGLE_CLIENT_ID && process.env.GOOGLE_CLIENT_SECRET);

// Fail fast in production if the signing secret is missing, too short, or a known
// placeholder — sessions/cookies are only secure when BETTER_AUTH_SECRET is a strong,
// non-default value. Stay frictionless in dev/test.
const KNOWN_WEAK_SECRETS = new Set([
  "dev-secret-please-change-0123456789abcdef",
]);
const authSecret = process.env.BETTER_AUTH_SECRET;
const secretIsWeak =
  !authSecret || authSecret.length < 32 || KNOWN_WEAK_SECRETS.has(authSecret);
if (secretIsWeak && process.env.NODE_ENV === "production") {
  throw new Error(
    "BETTER_AUTH_SECRET must be set in production to a strong value (>= 32 chars, not a known placeholder)."
  );
}

export const auth = betterAuth({
  appName: "Podcast Distribution AI",
  secret: process.env.BETTER_AUTH_SECRET,
  baseURL: process.env.BETTER_AUTH_URL ?? appUrl,
  database: prismaAdapter(prisma, { provider: "postgresql" }),

  // Built-in brute-force protection for auth endpoints (login, password reset, etc).
  // 30 requests per 60s window per IP.
  rateLimit: { enabled: true, window: 60, max: 30 },

  emailAndPassword: {
    enabled: true,
    // SECURITY GATE: unverified emails CANNOT sign in. Verification emails are sent
    // on signup (see emailVerification.sendOnSignUp below), so users can verify before
    // their first login.
    requireEmailVerification: true,
    minPasswordLength: 8,
    async sendResetPassword({ user, url }) {
      await sendEmail({
        to: user.email,
        subject: "Reset your Podcast Distribution AI password",
        html: emailLayout(
          "Reset your password",
          "Click the button below to choose a new password.",
          { label: "Reset password", url }
        ),
        text: `Reset your password: ${url}`,
      });
    },
  },

  emailVerification: {
    sendOnSignUp: true,
    async sendVerificationEmail({ user, url }) {
      await sendEmail({
        to: user.email,
        subject: "Verify your email for Podcast Distribution AI",
        html: emailLayout(
          "Confirm your email",
          "Confirm your email address to secure your account.",
          { label: "Verify email", url }
        ),
        text: `Verify your email: ${url}`,
      });
    },
  },

  socialProviders: googleConfigured
    ? {
        google: {
          clientId: process.env.GOOGLE_CLIENT_ID!,
          clientSecret: process.env.GOOGLE_CLIENT_SECRET!,
        },
      }
    : undefined,

  session: {
    expiresIn: 60 * 60 * 24 * 30, // 30 days
    updateAge: 60 * 60 * 24, // refresh daily
    // Cache the session in a signed cookie to avoid a DB hit on every request.
    // Tradeoff: a banned/demoted user keeps cached access until the cache expires,
    // so we keep the window short (60s). Shorter = faster revocation but more DB hits.
    cookieCache: { enabled: true, maxAge: 60 },
  },

  account: {
    accountLinking: { enabled: true, trustedProviders: ["google"] },
  },

  plugins: [
    admin({ defaultRole: "user", adminRoles: ["admin"] }),
    organization({
      teams: { enabled: true, maximumTeams: 1 },
      // Agency seat cap is enforced in app logic against the subscription's seat count.
      membershipLimit: 5,
    }),
    // Must remain last: lets Server Actions / route handlers set auth cookies.
    nextCookies(),
  ],
});

export type Session = typeof auth.$Infer.Session;