import { betterAuth } from "better-auth";
import { Pool } from "pg";

import { buildAuthOptions, type AdminUserAuthorizer } from "./auth-factory.ts";
import {
  isSelfHostedIdentityEnabled,
  readSelfHostedIdentityConfig,
  type SelfHostedIdentityConfig,
} from "./config.ts";
import type { EmailOtpSender } from "./contracts.ts";
import { FakeEmailOtpSender } from "./email/fake-email-otp-sender.ts";
import { ResendEmailOtpSender } from "./email/resend-email-otp-sender.ts";

interface AdminRoleRow {
  role: string;
  banned: boolean;
  ban_expires: Date | null;
}

export type IdentityAdminSurfaceRole = "admin";

export function createIdentityPool(databaseUrl: string): Pool {
  return new Pool({
    connectionString: databaseUrl,
    options: "-c search_path=identity,pg_catalog",
    application_name: "jyotisha-identity",
    max: 10,
    idleTimeoutMillis: 30_000,
    connectionTimeoutMillis: 5_000,
  });
}

function createDatabaseRoleAuthorizer(
  pool: Pool,
  allowedRoles: ReadonlySet<string>,
): AdminUserAuthorizer {
  return async (userId) => {
    const result = await pool.query<AdminRoleRow>(
      `
        select role, banned, ban_expires
        from identity.users
        where id = $1
        limit 1
      `,
      [userId],
    );
    const user = result.rows[0];
    if (!user) return false;

    if (user.banned) {
      const banExpiry = user.ban_expires?.getTime();
      if (banExpiry === undefined || !Number.isFinite(banExpiry)) return false;
      if (banExpiry > Date.now()) return false;
    }

    return user.role
      .split(",")
      .map((role) => role.trim())
      .some((role) => allowedRoles.has(role));
  };
}

export function createDatabaseAdminAuthorizer(
  pool: Pool,
): AdminUserAuthorizer {
  return createDatabaseRoleAuthorizer(pool, new Set(["admin"]));
}

export function createDatabaseAdminSurfaceAuthorizer(
  pool: Pool,
): AdminUserAuthorizer {
  return createDatabaseAdminAuthorizer(pool);
}

export interface IdentityAuthServices {
  pool: Pool;
  user: ReturnType<typeof betterAuth>;
}

interface IdentityAuthDependencies {
  pool?: Pool;
  emailSender?: EmailOtpSender;
}

export function createIdentityAuthServices(
  config: SelfHostedIdentityConfig,
  dependencies: IdentityAuthDependencies = {},
): IdentityAuthServices {
  const pool = dependencies.pool ?? createIdentityPool(config.databaseUrl);
  const emailSender =
    dependencies.emailSender ??
    (config.testOtp
      ? new FakeEmailOtpSender()
      : new ResendEmailOtpSender({
          apiKey: config.resendApiKey,
          from: config.resendFrom,
        }));
  return {
    pool,
    user: betterAuth(
      buildAuthOptions({
        config,
        database: pool,
        emailSender,
      }),
    ),
  };
}


export interface IdentityEmailOtpApi {
  sendVerificationOTP(input: {
    body: { email: string; type: "email-verification" };
  }): Promise<{ success: boolean }>;
  verifyEmailOTP(input: {
    body: { email: string; otp: string };
  }): Promise<unknown>;
}

export function getIdentityEmailOtpApi(
  env: NodeJS.ProcessEnv = process.env,
): IdentityEmailOtpApi {
  return getIdentityAuthServices(env).user.api as unknown as IdentityEmailOtpApi;
}

export interface IdentityTwoFactorApi {
  enableTwoFactor(input: {
    body: { password: string };
    headers: Headers;
    asResponse: true;
  }): Promise<Response>;
  verifyTOTP(input: {
    body: { code: string; trustDevice?: boolean };
    headers: Headers;
    asResponse: true;
  }): Promise<Response>;
  verifyBackupCode(input: {
    body: { code: string; disableSession?: boolean };
    headers: Headers;
    asResponse: true;
  }): Promise<Response>;
  generateBackupCodes(input: {
    body: { password: string };
    headers: Headers;
    asResponse: true;
  }): Promise<Response>;
  disableTwoFactor(input: {
    body: { password: string };
    headers: Headers;
    asResponse: true;
  }): Promise<Response>;
}

export function getIdentityTwoFactorApi(
  env: NodeJS.ProcessEnv = process.env,
): IdentityTwoFactorApi {
  return getIdentityAuthServices(env).user.api as unknown as IdentityTwoFactorApi;
}

const identityGlobal = globalThis as typeof globalThis & {
  jyotishaIdentityAuth?: IdentityAuthServices;
};

export function getIdentityAuthServices(
  env: NodeJS.ProcessEnv = process.env,
): IdentityAuthServices {
  if (!isSelfHostedIdentityEnabled(env)) {
    throw new Error("self-hosted identity is not enabled");
  }
  const config = readSelfHostedIdentityConfig(env);

  identityGlobal.jyotishaIdentityAuth ??= createIdentityAuthServices(config);
  return identityGlobal.jyotishaIdentityAuth;
}