import { AnimatePresence, motion } from 'framer-motion';
import React, { useCallback, useMemo, useState } from 'react';
import { symbiosisExamples } from '@/data/symbiosisExamples.ts';
import { useTranslation } from '@/hooks/useI18n.tsx';
import SectionHeader from '@/components/layout/SectionHeader.tsx';
import Button from '@/components/ui/Button.tsx';
import { Container, Flex, Grid } from '@/components/ui/layout';
import Select from '@/components/ui/Select.tsx';
import DemoCard from '@/components/landing/DemoCard.tsx';

interface SymbiosisDemoProps {
  onNavigateToMap: (page: 'map') => void;
}

const SymbiosisDemo = ({ onNavigateToMap }: SymbiosisDemoProps) => {
  const { t } = useTranslation();

  // State now holds only the key of the selected offer.
  const [selectedOfferKey, setSelectedOfferKey] = useState(symbiosisExamples[0].offer.key);

  // Derive the selected offer object from the key using useMemo for performance.
  const selectedOffer = useMemo(
    () => symbiosisExamples.find((ex) => ex.offer.key === selectedOfferKey) || null,
    [selectedOfferKey]
  );

  // Derive the available needs based on the selected offer.
  const availableNeeds = useMemo(() => selectedOffer?.needs || [], [selectedOffer]);

  // Initialize selected need key based on available needs
  const initialSelectedNeedKey = availableNeeds[0]?.key || '';
  const [selectedNeedKey, setSelectedNeedKey] = useState(initialSelectedNeedKey);

  // Derive the selected need object from its key.
  const selectedNeed = useMemo(
    () => availableNeeds.find((n) => n.key === selectedNeedKey) || null,
    [availableNeeds, selectedNeedKey]
  );

  // Event handlers now only update the keys.
  const handleOfferChange = useCallback((e: React.ChangeEvent<HTMLSelectElement>) => {
    setSelectedOfferKey(e.target.value);
  }, []);

  const handleNeedChange = useCallback((e: React.ChangeEvent<HTMLSelectElement>) => {
    setSelectedNeedKey(e.target.value);
  }, []);

  const translatedSectors = useMemo(
    () => ({
      production: t('sectors.production'),
      construction: t('sectors.construction'),
      recreation: t('sectors.recreation'),
      logistics: t('sectors.logistics'),
    }),
    [t]
  );

  return (
    <section
      className="bg-background min-h-screen flex items-center scroll-snap-align-start"
      aria-labelledby="symbiosis-demo-title"
    >
      <Container className="py-16 sm:py-24 w-full">
        <SectionHeader
          id="symbiosis-demo-title"
          title={t('symbiosisDemo.title')}
          subtitle={t('symbiosisDemo.subtitle')}
          className="mb-10 sm:mb-12"
        />
        <Grid cols={{ md: 2 }} gap="md" className="mb-12">
          <div>
            <label htmlFor="offer-select" className="block text-sm font-medium mb-1">
              {t('symbiosisDemo.offerLabel')}
            </label>
            <Select id="offer-select" value={selectedOfferKey} onChange={handleOfferChange}>
              {symbiosisExamples.map((ex) => (
                <option key={ex.offer.key} value={ex.offer.key}>
                  {t(ex.offer.nameKey)}
                </option>
              ))}
            </Select>
          </div>
          <div>
            <label htmlFor="need-select" className="block text-sm font-medium mb-1">
              {t('symbiosisDemo.needLabel')}
            </label>
            <Select
              id="need-select"
              value={selectedNeedKey}
              onChange={handleNeedChange}
              disabled={!selectedOffer}
            >
              {availableNeeds.map((need) => (
                <option key={need.key} value={need.key}>
                  {t(need.nameKey)}
                </option>
              ))}
            </Select>
          </div>
        </Grid>

        <Flex
          direction="col"
          align="center"
          justify="between"
          gap="2xl"
          className="relative mt-16 sm:flex-row sm:gap-0"
        >
          {selectedOffer && (
            <DemoCard
              icon={selectedOffer.offer.icon}
              sector={translatedSectors[selectedOffer.offer.sector]}
              item={t(selectedOffer.offer.nameKey)}
              type="Offer"
            />
          )}

          <div className="w-full sm:w-2/12 h-16 sm:h-auto flex items-center justify-center">
            <svg className="w-full h-full" viewBox="0 0 100 100" preserveAspectRatio="none">
              <motion.path
                key={`${selectedOffer?.offer.key}-${selectedNeed?.key}`}
                d="M 5 50 Q 50 20 95 50"
                stroke="hsl(var(--primary))"
                strokeWidth="2"
                fill="none"
                strokeDasharray="4 4"
                initial={{ pathLength: 0, opacity: 0 }}
                animate={{ pathLength: 1, opacity: 1 }}
                transition={{ duration: 0.8, ease: 'easeInOut' }}
              />
            </svg>
          </div>

          {selectedNeed && (
            <DemoCard
              icon={selectedNeed.icon}
              sector={translatedSectors[selectedNeed.sector]}
              item={t(selectedNeed.nameKey)}
              type="Need"
            />
          )}
        </Flex>

        <AnimatePresence mode="wait">
          <motion.div
            key={selectedNeed?.key}
            initial={{ opacity: 0, y: 10 }}
            animate={{ opacity: 1, y: 0 }}
            exit={{ opacity: 0, y: -10 }}
            transition={{ duration: 0.3 }}
            className="mt-12 text-center max-w-2xl mx-auto p-4 bg-muted rounded-lg"
            aria-live="polite"
          >
            <p className="text-lg text-foreground">
              {selectedNeed ? t(selectedNeed.descriptionKey) : ' '}
            </p>
          </motion.div>
        </AnimatePresence>

        <div className="text-center mt-16">
          <Button
            size="lg"
            onClick={() => onNavigateToMap('map')}
            className="shadow-lg shadow-primary/20 hover:shadow-xl hover:shadow-primary/30"
          >
            {t('symbiosisDemo.ctaButton')}
          </Button>
        </div>
      </Container>
    </section>
  );
};

export default React.memo(SymbiosisDemo);