import { Link } from 'expo-router';
import { useMemo, useState } from 'react';
import {
  ActivityIndicator,
  KeyboardAvoidingView,
  Platform,
  StyleSheet,
  Text,
  View,
} from 'react-native';
import { SafeAreaView } from 'react-native-safe-area-context';

import { Button } from '@/components/common/Button';
import { Catamaran, FunnelSans } from '@/constants/fonts';
import { Input } from '@/components/common/Input';
import { Palette } from '@/constants/palette';
import { Radius, Spacing } from '@/constants/styles';
import { mapFirebaseAuthError } from '@/lib/firebase-auth-errors';
import { loginWithEmail, registerWithEmail } from '@/services/auth';

type AuthMode = 'login' | 'register';

type AuthFormProps = {
  mode: AuthMode;
};

const copyByMode = {
  login: {
    title: 'Connexion',
    submitLabel: 'Se connecter',
    switchLabel: "Pas encore de compte ? S'inscrire",
    switchHref: '/register' as const,
  },
  register: {
    title: 'Inscription',
    submitLabel: "S'inscrire",
    switchLabel: 'Déjà un compte ? Se connecter',
    switchHref: '/login' as const,
  },
} as const;

export function AuthForm({ mode }: AuthFormProps) {
  const copy = copyByMode[mode];
  const [username, setUsername] = useState('');
  const [email, setEmail] = useState('leon.morival@gmail.com');
  const [password, setPassword] = useState('Furioza98*');
  const [error, setError] = useState<string | null>(null);
  const [isSubmitting, setIsSubmitting] = useState(false);

  const isFormValid = useMemo(() => {
    if (!email.trim() || !password.trim()) {
      return false;
    }

    if (mode === 'register' && !username.trim()) {
      return false;
    }

    return true;
  }, [username, email, mode, password]);

  const handleSubmit = async () => {
    if (!isFormValid || isSubmitting) {
      return;
    }

    setError(null);
    setIsSubmitting(true);

    try {
      if (mode === 'login') {
        await loginWithEmail(email, password);
      } else {
        await registerWithEmail({
          email,
          password,
          username,
        });
      }
    } catch (submitError) {
      setError(mapFirebaseAuthError(submitError));
    } finally {
      setIsSubmitting(false);
    }
  };

  return (
    <SafeAreaView style={styles.safeArea}>
      <KeyboardAvoidingView
        behavior={Platform.OS === 'ios' ? 'padding' : 'height'}
        style={styles.keyboardView}
      >
        <View style={styles.container}>
          <View style={styles.hero}>
            <Text style={styles.title}>{copy.title}</Text>
          </View>

          <View style={styles.card}>
            {mode === 'register' ? (
              <Input
                autoCapitalize="words"
                containerStyle={styles.field}
                label="Nom"
                onChangeText={setUsername}
                placeholder="Pierre"
                value={username}
              />
            ) : null}

            <Input
              autoCapitalize="none"
              autoComplete="email"
              containerStyle={styles.field}
              keyboardType="email-address"
              label="Email"
              onChangeText={setEmail}
              placeholder="pierre@email.com"
              value={email}
            />

            <Input
              autoCapitalize="none"
              autoComplete={mode === 'login' ? 'password' : 'new-password'}
              containerStyle={styles.field}
              label="Mot de passe"
              onChangeText={setPassword}
              placeholder="••••••••"
              secureTextEntry
              value={password}
            />

            {error ? <Text style={styles.error}>{error}</Text> : null}

            <Button
              disabled={!isFormValid || isSubmitting}
              onPress={handleSubmit}
              style={styles.submitButton}
              title={isSubmitting ? 'Chargement...' : copy.submitLabel}
            />

            {isSubmitting ? (
              <ActivityIndicator color={Palette.black} style={styles.loader} />
            ) : null}

            <Link href={copy.switchHref} style={styles.switchLink}>
              {copy.switchLabel}
            </Link>
          </View>
        </View>
      </KeyboardAvoidingView>
    </SafeAreaView>
  );
}

const styles = StyleSheet.create({
  safeArea: {
    flex: 1,
    backgroundColor: Palette.cream,
  },
  keyboardView: {
    flex: 1,
  },
  container: {
    flex: 1,
    justifyContent: 'center',
    paddingHorizontal: Spacing.lg,
    gap: Spacing.lg,
    backgroundColor: Palette.cream,
  },
  hero: {
    gap: Spacing.sm,
  },

  title: {
    ...Catamaran.extraBold36,
    color: Palette.black,
  },
  subtitle: {
    ...FunnelSans.regular16,
    color: Palette.gray,
  },

  card: {
    backgroundColor: Palette.white,
    borderColor: Palette.cream,
    borderRadius: Radius.xl,
    borderWidth: 1,
    padding: 20,
    gap: Spacing.md,
  },
  field: {
    width: '100%',
  },
  error: {
    ...FunnelSans.semiBold14,
    color: Palette.danger,
  },
  submitButton: {
    minHeight: 52,
  },
  loader: {
    marginTop: -4,
  },
  switchLink: {
    ...FunnelSans.semiBold14,
    color: Palette.black,
    textAlign: 'center',
    textDecorationLine: 'underline',
  },
});