import { useState } from 'react';
import Form from 'antd/es/form';
import Input from 'antd/es/input';
import Button from 'antd/es/button';
import Checkbox from 'antd/es/checkbox';
import Tabs from 'antd/es/tabs';
import Alert from 'antd/es/alert';
import Typography from 'antd/es/typography';
import { registerCustomer, loginCustomer } from './customerApi';
import { useCustomerAuth } from './CustomerAuthContext';

const { Text } = Typography;

export type AuthMode = 'register' | 'login';

// Must stay identical to MARKETING_CONSENT_TEXT in backend/src/utils.ts, which
// is what gets stored verbatim against the customer's consent record. The point
// of storing it is that the record says what the customer actually saw, so a
// label that differs from the stored string defeats the whole mechanism. Before
// this was shared there were three wordings in play — this one, a shorter one in
// the cart prompt, and the string the server actually recorded — and none of
// them matched.
//
// Widened for #56 so it covers the Brevo tracker as well as email. The tracker
// is gated on whether a customer's *stored* copy of this sentence matches the
// current one, so changing it here does not retroactively widen the consent of
// anyone who agreed to the previous wording.
export const MARKETING_CONSENT_TEXT =
  'I want to receive occasional emails about new one-of-a-kind items from Redefined Designs, and I agree that what I browse and buy here may be shared with our email provider to help choose what they contain. I can unsubscribe at any time.';

type Props = Readonly<{
  mode: AuthMode;
  onModeChange: (mode: AuthMode) => void;
  onForgotPassword: () => void;
  // Called once the session exists. What that means differs by caller: the
  // route closes back to the page behind it, while the cart and favorite
  // prompts resume the action the customer was interrupted doing.
  onSuccess: () => void;
}>;

// The one implementation of signing in and registering. It was previously
// written twice — once as the /login and /register pages, once inside the
// prompt shown when a signed-out visitor adds to the cart — which had already
// drifted in consent wording and in which links each offered.
export default function AuthForm({ mode, onModeChange, onForgotPassword, onSuccess }: Props) {
  const [error, setError] = useState<string | null>(null);
  const [loading, setLoading] = useState(false);
  const { refresh } = useCustomerAuth();

  async function submit(action: () => Promise<unknown>) {
    setLoading(true);
    setError(null);
    try {
      await action();
      refresh();
      onSuccess();
    } catch (err) {
      setError((err as Error).message);
    } finally {
      setLoading(false);
    }
  }

  return (
    <>
      {error && <Alert type="error" showIcon message={error} style={{ marginBottom: 16 }} />}
      <Tabs
        activeKey={mode}
        onChange={(key) => {
          // A stale error from the other tab would read as though it applied to
          // the form now on screen.
          setError(null);
          onModeChange(key as AuthMode);
        }}
        items={[
          {
            key: 'register',
            label: 'Create Account',
            children: (
              <Form
                layout="vertical"
                onFinish={(values) =>
                  submit(() =>
                    registerCustomer(values.email, values.password, values.firstName, values.lastName, !!values.marketingConsent)
                  )
                }
              >
                <Form.Item
                  name="firstName"
                  label="First name"
                  rules={[{ required: true, message: 'First name is required' }]}
                >
                  <Input autoComplete="given-name" />
                </Form.Item>
                <Form.Item
                  name="lastName"
                  label="Last name"
                  rules={[{ required: true, message: 'Last name is required' }]}
                >
                  <Input autoComplete="family-name" />
                </Form.Item>
                <Form.Item name="email" label="Email" rules={[{ required: true, type: 'email' }]}>
                  <Input autoComplete="email" />
                </Form.Item>
                <Form.Item
                  name="password"
                  label="Password"
                  rules={[{ required: true, min: 8, message: 'At least 8 characters' }]}
                >
                  <Input.Password autoComplete="new-password" />
                </Form.Item>
                <Form.Item name="marketingConsent" valuePropName="checked" initialValue={false}>
                  <Checkbox>{MARKETING_CONSENT_TEXT}</Checkbox>
                </Form.Item>
                <Button type="primary" htmlType="submit" block loading={loading}>
                  Create account
                </Button>
                <Text type="secondary" style={{ fontSize: 12, display: 'block', marginTop: 12 }}>
                  {/* Opens in a new tab deliberately: following it in place would
                      discard a part-filled signup form, and /privacy has no way
                      back of its own yet (#52). */}
                  By creating an account you agree to our{' '}
                  <a href="/privacy" target="_blank" rel="noopener noreferrer">Privacy Policy</a>.
                </Text>
              </Form>
            )
          },
          {
            key: 'login',
            label: 'Log In',
            children: (
              <Form
                layout="vertical"
                onFinish={(values) => submit(() => loginCustomer(values.email, values.password))}
              >
                <Form.Item name="email" label="Email" rules={[{ required: true, type: 'email' }]}>
                  <Input autoComplete="email" />
                </Form.Item>
                <Form.Item name="password" label="Password" rules={[{ required: true }]}>
                  <Input.Password autoComplete="current-password" />
                </Form.Item>
                <Button type="primary" htmlType="submit" block loading={loading}>
                  Log in
                </Button>
                <Button type="link" style={{ paddingInline: 0, marginTop: 8 }} onClick={onForgotPassword}>
                  Forgot password?
                </Button>
              </Form>
            )
          }
        ]}
      />
    </>
  );
}