import React, { useState } from 'react';
import {
  Image,
  KeyboardAvoidingView,
  Platform,
  Pressable,
  ScrollView,
  StatusBar,
  StyleSheet,
  Text,
  useWindowDimensions,
  View,
} from 'react-native';
import { useSafeAreaInsets } from 'react-native-safe-area-context';
import type { NativeStackScreenProps } from '@react-navigation/native-stack';
import { authApi } from '../api/auth';
import type { RootStackParamList } from '../navigation/types';
import { useAuth } from '../context/AuthContext';
import { colors, radii, spacing, typography } from '../theme';
import { PrimaryButton, TextField } from '../components/ui';

type Props = NativeStackScreenProps<RootStackParamList, 'Login'>;

const BRAND_ORANGE = '#F7941D';
const BRAND_ORANGE_DARK = '#E8780A';
const BUTTON_HEIGHT = 52;
const BOTTOM_BAR_PAD_Y = 16;
export function LoginScreen({ navigation }: Props) {
  const { refreshUser } = useAuth();
  const { height: windowHeight } = useWindowDimensions();
  const insets = useSafeAreaInsets();
  const heroHeight = Math.round(windowHeight * 0.42);

  const [email, setEmail] = useState('');
  const [password, setPassword] = useState('');
  const [showPw, setShowPw] = useState(false);
  const [error, setError] = useState<string | null>(null);
  const [loading, setLoading] = useState(false);

  const submit = async () => {
    setError(null);
    const em = email.trim();
    if (!em || !password) {
      setError('Email and password are required');
      return;
    }
    setLoading(true);
    let res;
    try {
      res = await authApi.login(em, password);
    } catch {
      setLoading(false);
      setError('Network error. Check API URL and that the backend is running.');
      return;
    }
    setLoading(false);
    if (res.error) {
      setError(res.error);
      return;
    }
    const d = res.data;
    if (d && 'requiresTwoFactor' in d && d.requiresTwoFactor) {
      navigation.navigate('Login2FA', {
        twoFactorToken: d.twoFactorToken,
        email: d.email,
      });
      return;
    }
    await refreshUser();
    navigation.replace('Events');
  };

  return (
    <View style={styles.root}>
      <StatusBar barStyle="light-content" backgroundColor={BRAND_ORANGE} />

      {/* Orange hero — fixed pixel height so it always renders */}
      <View style={[styles.hero, { height: heroHeight + insets.top, paddingTop: insets.top + 24 }]}>
        <View style={styles.heroGradientDark} />
        <View style={styles.heroCircleA} />
        <View style={styles.heroCircleB} />

        <View style={styles.logoCard}>
          <Image
            source={require('../assets/eventbuzz-logo.png')}
            style={styles.logo}
            resizeMode="contain"
          />
        </View>
        <Text style={styles.heroSubtitle}>Attendance Management</Text>
      </View>

      <KeyboardAvoidingView
        style={styles.formArea}
        behavior={Platform.OS === 'ios' ? 'padding' : undefined}
      >
        <View style={styles.sheet}>
          <ScrollView
            keyboardShouldPersistTaps="handled"
            contentContainerStyle={[
              styles.sheetScroll,
              {
                paddingBottom:
                  BUTTON_HEIGHT +
                  BOTTOM_BAR_PAD_Y * 2 +
                  Math.max(insets.bottom, 16) +
                  18,
              },
            ]}
            showsVerticalScrollIndicator={false}
          >
            <Text style={styles.title}>Welcome back</Text>
            <Text style={styles.sub}>Sign in to your dashboard account</Text>

            {error ? (
              <View style={styles.errorBox}>
                <Text style={styles.errorText}>{error}</Text>
              </View>
            ) : null}

            <View style={styles.fields}>
              <TextField
                label="Email address"
                value={email}
                onChangeText={setEmail}
                autoCapitalize="none"
                keyboardType="email-address"
                autoComplete="email"
                placeholder="you@example.com"
                left={<Text style={styles.fieldIcon}>✉</Text>}
              />

              <TextField
                label="Password"
                value={password}
                onChangeText={setPassword}
                secureTextEntry={!showPw}
                placeholder="Your password"
                left={<Text style={styles.fieldIcon}>🔒</Text>}
                right={
                  <Pressable onPress={() => setShowPw((v) => !v)} hitSlop={10}>
                    <Text style={styles.fieldIcon}>{showPw ? '🙈' : '👁'}</Text>
                  </Pressable>
                }
              />
            </View>
          </ScrollView>

          <View style={[styles.bottomBar, { paddingBottom: Math.max(insets.bottom, 16) }]}>
            <PrimaryButton
              title={loading ? 'Signing in…' : 'Sign In'}
              loading={loading}
              onPress={submit}
              style={styles.signInBtn}
            />
          </View>
        </View>
      </KeyboardAvoidingView>
    </View>
  );
}

const styles = StyleSheet.create({
  root: {
    flex: 1,
    backgroundColor: BRAND_ORANGE,
  },
  hero: {
    backgroundColor: BRAND_ORANGE,
    alignItems: 'center',
    justifyContent: 'flex-end',
    paddingBottom: 36,
    overflow: 'hidden',
  },
  heroGradientDark: {
    position: 'absolute',
    right: 0,
    bottom: 0,
    width: '70%',
    height: '80%',
    backgroundColor: BRAND_ORANGE_DARK,
    opacity: 0.45,
    borderTopLeftRadius: 200,
  },
  heroCircleA: {
    position: 'absolute',
    width: 176,
    height: 176,
    borderRadius: 88,
    right: -44,
    top: -36,
    backgroundColor: 'rgba(255,255,255,0.12)',
  },
  heroCircleB: {
    position: 'absolute',
    width: 128,
    height: 128,
    borderRadius: 64,
    left: -28,
    bottom: 8,
    backgroundColor: 'rgba(255,255,255,0.10)',
  },
  logoCard: {
    backgroundColor: '#fff',
    borderRadius: 16,
    paddingHorizontal: 20,
    paddingVertical: 16,
    marginBottom: 14,
    zIndex: 2,
    shadowColor: '#000',
    shadowOffset: { width: 0, height: 8 },
    shadowOpacity: 0.12,
    shadowRadius: 20,
    elevation: 8,
  },
  logo: { width: 144, height: 52 },
  heroSubtitle: {
    color: 'rgba(255,255,255,0.85)',
    fontSize: 14,
    letterSpacing: 0.4,
    zIndex: 2,
  },
  formArea: {
    flex: 1,
  },
  sheet: {
    flex: 1,
    marginTop: -28,
    backgroundColor: '#fff',
    borderTopLeftRadius: 28,
    borderTopRightRadius: 28,
    shadowColor: '#000',
    shadowOffset: { width: 0, height: -4 },
    shadowOpacity: 0.08,
    shadowRadius: 24,
    elevation: 12,
    overflow: 'hidden',
  },
  sheetScroll: {
    paddingHorizontal: spacing.xl,
    paddingTop: 32,
    paddingBottom: 16,
  },
  title: { ...typography.title, color: colors.text, marginBottom: 6 },
  sub: { ...typography.body, color: colors.muted, marginBottom: 24 },
  fields: { gap: 16 },
  fieldIcon: { fontSize: 16, color: '#9CA3AF' },
  errorBox: {
    backgroundColor: 'rgba(220,38,38,0.08)',
    borderWidth: 1,
    borderColor: 'rgba(220,38,38,0.18)',
    borderRadius: radii.md,
    paddingHorizontal: 14,
    paddingVertical: 12,
    marginBottom: 14,
  },
  errorText: { ...typography.body, color: colors.error },
  signInBtn: {
    borderRadius: 14,
    shadowColor: BRAND_ORANGE,
    shadowOffset: { width: 0, height: 8 },
    shadowOpacity: 0.35,
    shadowRadius: 16,
    elevation: 6,
  },
  bottomBar: {
    position: 'absolute',
    left: 0,
    right: 0,
    bottom: 0,
    paddingHorizontal: spacing.xl,
    paddingTop: BOTTOM_BAR_PAD_Y,
    backgroundColor: '#fff',
  },
});