import React, { useEffect, useMemo } from 'react';
import { ScrollView, StyleSheet, Text, View } from 'react-native';
import type { NativeStackScreenProps } from '@react-navigation/native-stack';

import { useAppDispatch, useAppSelector } from '../../../app/hooks';
import { Button, Card, Input, ScreenShell } from '../../../components';
import type { InsuranceStackParamList } from '../../../navigation/types';
import { useTheme, fontFamily } from '../../../theme';
import { formatCompactCurrency, formatCurrency } from '../../../utils/formatters';
import { InsuranceCategoryChip } from '../components/InsuranceCategoryChip';
import { InsuranceRangeSlider } from '../components/InsuranceRangeSlider';
import { useEstimateInsurancePremiumQuery } from '../services/insuranceApi';
import { insuranceActions } from '../store/insuranceSlice';
import { selectInsuranceCalculator } from '../store/insuranceSelectors';
import { INSURANCE_CATEGORIES } from '../types';

type Props = NativeStackScreenProps<InsuranceStackParamList, 'InsuranceCalculator'>;

export default function InsuranceCalculatorScreen({ navigation, route }: Props) {
  const dispatch = useAppDispatch();
  const theme = useTheme();
  const calculator = useAppSelector(selectInsuranceCalculator);
  const effectiveCategory = calculator.category;

  useEffect(() => {
    if (route.params?.category) {
      dispatch(
        insuranceActions.updateInsuranceCalculator({
          field: 'category',
          value: route.params.category,
        }),
      );
    }
  }, [dispatch, route.params?.category]);
  const estimateQuery = useEstimateInsurancePremiumQuery({
    ...calculator,
    category: effectiveCategory,
  });

  const estimate = estimateQuery.data;
  const coverageValue = useMemo(
    () => Number(calculator.coverageAmount || 0),
    [calculator.coverageAmount],
  );

  return (
    <ScreenShell title="Calculator" subtitle="Estimate premiums by age, cover, and tenure">
      <ScrollView contentContainerStyle={styles.scroll} showsVerticalScrollIndicator={false} keyboardShouldPersistTaps="handled">
        <Card style={styles.sectionCard}>
          <Text style={[styles.sectionTitle, { color: theme.colors.textPrimary }]}>
            Policy category
          </Text>
          <View style={styles.categoryWrap}>
            {INSURANCE_CATEGORIES.map((category) => (
              <InsuranceCategoryChip
                key={category}
                category={category}
                selected={effectiveCategory === category}
                onPress={() =>
                  dispatch(
                    insuranceActions.updateInsuranceCalculator({
                      field: 'category',
                      value: category,
                    }),
                  )
                }
              />
            ))}
          </View>
        </Card>

        <Card style={styles.sectionCard}>
          <Text style={[styles.sectionTitle, { color: theme.colors.textPrimary }]}>
            Adjust your assumptions
          </Text>
          <InsuranceRangeSlider
            label="Age"
            min={18}
            max={70}
            step={1}
            value={Number(calculator.age || 18)}
            onValueChange={(value) =>
              dispatch(
                insuranceActions.updateInsuranceCalculator({
                  field: 'age',
                  value: String(value),
                }),
              )
            }
          />
          <InsuranceRangeSlider
            label="Coverage"
            min={100000}
            max={20000000}
            step={100000}
            value={coverageValue || 100000}
            formatter={(value) => formatCompactCurrency(value)}
            onValueChange={(value) =>
              dispatch(
                insuranceActions.updateInsuranceCalculator({
                  field: 'coverageAmount',
                  value: String(value),
                }),
              )
            }
          />
          <InsuranceRangeSlider
            label="Tenure"
            min={1}
            max={30}
            step={1}
            value={Number(calculator.tenureYears || 1)}
            suffix=" yr"
            onValueChange={(value) =>
              dispatch(
                insuranceActions.updateInsuranceCalculator({
                  field: 'tenureYears',
                  value: String(value),
                }),
              )
            }
          />
        </Card>

        <Card style={styles.sectionCard}>
          <Text style={[styles.sectionTitle, { color: theme.colors.textPrimary }]}>
            Manual inputs
          </Text>
          <Input
            label="Age"
            keyboardType="number-pad"
            value={calculator.age}
            onChangeText={(value) =>
              dispatch(
                insuranceActions.updateInsuranceCalculator({ field: 'age', value }),
              )
            }
          />
          <Input
            label="Coverage Amount"
            keyboardType="number-pad"
            value={calculator.coverageAmount}
            onChangeText={(value) =>
              dispatch(
                insuranceActions.updateInsuranceCalculator({
                  field: 'coverageAmount',
                  value,
                }),
              )
            }
          />
          <Input
            label="Tenure Years"
            keyboardType="number-pad"
            value={calculator.tenureYears}
            onChangeText={(value) =>
              dispatch(
                insuranceActions.updateInsuranceCalculator({
                  field: 'tenureYears',
                  value,
                }),
              )
            }
          />
        </Card>

        <Card style={styles.resultCard}>
          <Text style={[styles.sectionTitle, { color: theme.colors.textPrimary }]}>
            Estimated premium
          </Text>
          <View style={styles.resultGrid}>
            <View style={[styles.resultMetric, { backgroundColor: theme.colors.surfaceMuted }]}>
              <Text style={[styles.resultLabel, { color: theme.colors.textSecondary }]}>
                Monthly
              </Text>
              <Text style={[styles.resultValue, { color: theme.colors.textPrimary }]}>
                {estimate ? formatCurrency(estimate.monthlyPremium) : '--'}
              </Text>
            </View>
            <View style={[styles.resultMetric, { backgroundColor: theme.colors.surfaceMuted }]}>
              <Text style={[styles.resultLabel, { color: theme.colors.textSecondary }]}>
                Annual
              </Text>
              <Text style={[styles.resultValue, { color: theme.colors.textPrimary }]}>
                {estimate ? formatCurrency(estimate.annualPremium) : '--'}
              </Text>
            </View>
          </View>
          <Text style={[styles.recommendation, { color: theme.colors.textSecondary }]}>
            Recommended protection: {estimate ? formatCompactCurrency(estimate.recommendedCover) : '--'}
          </Text>
          <Button
            title="Buy This Cover"
            onPress={() =>
              navigation.navigate('BuyInsurance', { category: effectiveCategory })
            }
          />
        </Card>
      </ScrollView>
    </ScreenShell>
  );
}

const styles = StyleSheet.create({
  scroll: {
    gap: 16,
    paddingBottom: 28,
  },
  sectionCard: {
    gap: 14,
  },
  sectionTitle: {
    fontSize: 16,
    fontFamily: fontFamily.bold,
  },
  categoryWrap: {
    flexDirection: 'row',
    flexWrap: 'wrap',
    gap: 10,
  },
  resultCard: {
    gap: 14,
  },
  resultGrid: {
    flexDirection: 'row',
    gap: 12,
  },
  resultMetric: {
    flex: 1,
    borderRadius: 16,
    padding: 14,
    gap: 4,
  },
  resultLabel: {
    fontSize: 11,
    fontFamily: fontFamily.bold,
    textTransform: 'uppercase',
    letterSpacing: 0.5,
  },
  resultValue: {
    fontSize: 18,
    fontFamily: fontFamily.bold,
  },
  recommendation: {
    fontSize: 12,
    lineHeight: 18,
  },
});