import { useState } from 'react';
import { FlatList, Modal, Pressable, StyleSheet, Text, TextInput, View, type ViewStyle } from 'react-native';
import Animated, { FadeIn, FadeOut, ZoomIn } from 'react-native-reanimated';
import { EMOJI_PICKER_GROUPS, QUICK_REACTIONS, searchEmoji, type ReactionDTO } from '@musicshare/shared';
import { api } from '@/lib/api';
import { showError } from '@/lib/errors';
import { tapHaptic } from '@/lib/haptics';
import { useSession } from '@/lib/session';
import { colors, radius, space } from '@/lib/theme';

/**
 * Emoji reactions on one play. Tap an emoji to add yours (or take it back); "☺+"
 * opens the quick six, and "＋" the full picker. One reaction per person.
 */
export function Reactions({
  listenId,
  reactions,
  ownerId,
  style,
}: {
  listenId: string | null;
  reactions: ReactionDTO[];
  ownerId: string;
  style?: ViewStyle;
}) {
  const { me } = useSession();
  // The server's answer to our last tap, until fresh props arrive (e.g. a realtime update).
  const [local, setLocal] = useState<{ from: ReactionDTO[]; value: ReactionDTO[] } | null>(null);
  const shown = local && local.from === reactions ? local.value : reactions;
  const [quickOpen, setQuickOpen] = useState(false);
  const [pickerOpen, setPickerOpen] = useState(false);

  const canReact = Boolean(me && listenId && me.id !== ownerId);
  if (!listenId || (!canReact && shown.length === 0)) return null;
  const mine = me ? shown.find((r) => r.users.some((u) => u.id === me.id))?.emoji : undefined;

  const choose = async (emoji: string) => {
    setQuickOpen(false);
    setPickerOpen(false);
    tapHaptic();
    try {
      const value = emoji === mine ? await api.unreact(listenId) : await api.react(listenId, emoji);
      setLocal({ from: reactions, value });
    } catch (err) {
      showError(err, "Couldn't react");
    }
  };

  return (
    <View style={[styles.wrap, style]}>
      <View style={styles.row}>
        {shown.map((r) => (
          <Animated.View key={r.emoji} entering={ZoomIn.springify()}>
            <Pressable
              disabled={!canReact}
              onPress={() => choose(r.emoji)}
              accessibilityRole="button"
              accessibilityLabel={`${r.emoji} ${r.count}: ${names(r)}`}
              style={({ pressed }) => [styles.chip, r.emoji === mine && styles.mine, pressed && { transform: [{ scale: 0.9 }] }]}>
              <Text style={styles.emoji}>{r.emoji}</Text>
              {r.count > 1 && <Text style={styles.count}>{r.count}</Text>}
            </Pressable>
          </Animated.View>
        ))}
        {canReact && (
          <Pressable
            onPress={() => setQuickOpen((v) => !v)}
            accessibilityRole="button"
            accessibilityLabel="Add a reaction"
            hitSlop={6}
            style={[styles.chip, quickOpen && styles.mine]}>
            <Text style={[styles.emoji, { color: colors.muted }]}>☺</Text>
            <Text style={[styles.count, { color: colors.muted }]}>+</Text>
          </Pressable>
        )}
      </View>
      {quickOpen && (
        <Animated.View entering={FadeIn.duration(150)} exiting={FadeOut.duration(120)} style={styles.quick}>
          {QUICK_REACTIONS.map((e) => (
            <Pressable key={e} onPress={() => choose(e)} hitSlop={4} style={[styles.quickItem, e === mine && styles.mine]} accessibilityLabel={`React ${e}`}>
              <Text style={styles.quickEmoji}>{e}</Text>
            </Pressable>
          ))}
          <Pressable onPress={() => (setQuickOpen(false), setPickerOpen(true))} hitSlop={4} style={styles.quickItem} accessibilityLabel="More emoji">
            <Text style={[styles.quickEmoji, { color: colors.muted, fontSize: 22 }]}>＋</Text>
          </Pressable>
        </Animated.View>
      )}
      <EmojiPicker visible={pickerOpen} onPick={choose} onClose={() => setPickerOpen(false)} />
    </View>
  );
}

function names(r: ReactionDTO) {
  const list = r.users.map((u) => u.displayName ?? u.username);
  const extra = r.count - list.length;
  return extra > 0 ? `${list.join(', ')} and ${extra} more` : list.join(', ');
}

/** Every emoji, by category, with search, in a bottom sheet. */
function EmojiPicker({ visible, onPick, onClose }: { visible: boolean; onPick: (emoji: string) => void; onClose: () => void }) {
  const [query, setQuery] = useState('');
  const [group, setGroup] = useState(0);
  const results = query.trim() ? searchEmoji(query, 120) : EMOJI_PICKER_GROUPS[group]!.emojis;
  return (
    <Modal visible={visible} animationType="slide" transparent onRequestClose={onClose}>
      <Pressable style={styles.backdrop} onPress={onClose} accessibilityLabel="Close" />
      <View style={styles.sheet}>
        <TextInput
          value={query}
          onChangeText={setQuery}
          placeholder="Search emoji"
          placeholderTextColor={colors.muted}
          style={styles.search}
          autoCorrect={false}
        />
        {!query.trim() && (
          <View style={styles.tabs}>
            {EMOJI_PICKER_GROUPS.map((g, i) => (
              <Pressable key={g.name} onPress={() => setGroup(i)} accessibilityLabel={g.name} style={[styles.tab, i === group && styles.tabOn]}>
                <Text style={styles.tabEmoji}>{g.emojis[0]?.emoji}</Text>
              </Pressable>
            ))}
          </View>
        )}
        <FlatList
          data={results}
          key={query.trim() ? 'search' : `group-${group}`}
          numColumns={8}
          keyExtractor={(e) => e.emoji}
          initialNumToRender={64}
          keyboardShouldPersistTaps="handled"
          renderItem={({ item }) => (
            <Pressable onPress={() => onPick(item.emoji)} style={styles.cell} accessibilityLabel={item.name}>
              <Text style={styles.cellEmoji}>{item.emoji}</Text>
            </Pressable>
          )}
          ListEmptyComponent={<Text style={{ color: colors.muted, padding: space.lg }}>No emoji match “{query}”.</Text>}
        />
      </View>
    </Modal>
  );
}

const styles = StyleSheet.create({
  wrap: { marginTop: space.md, gap: space.sm },
  row: { flexDirection: 'row', flexWrap: 'wrap', gap: 6 },
  chip: {
    flexDirection: 'row',
    alignItems: 'center',
    gap: 3,
    paddingHorizontal: 9,
    paddingVertical: 3,
    borderRadius: radius.pill,
    backgroundColor: 'rgba(255,255,255,0.07)',
    borderWidth: StyleSheet.hairlineWidth,
    borderColor: 'rgba(255,255,255,0.16)',
  },
  mine: { backgroundColor: 'rgba(123,47,247,0.3)', borderColor: 'rgba(123,47,247,0.75)' },
  emoji: { fontSize: 16 },
  count: { color: colors.text, fontSize: 12, fontVariant: ['tabular-nums'] },
  quick: {
    flexDirection: 'row',
    alignSelf: 'flex-start',
    alignItems: 'center',
    gap: 2,
    padding: 4,
    borderRadius: radius.pill,
    backgroundColor: '#1a1535',
    borderWidth: StyleSheet.hairlineWidth,
    borderColor: 'rgba(255,255,255,0.16)',
  },
  quickItem: { width: 40, height: 40, borderRadius: 20, alignItems: 'center', justifyContent: 'center' },
  quickEmoji: { fontSize: 26 },
  backdrop: { flex: 1, backgroundColor: 'rgba(5,3,15,0.6)' },
  sheet: {
    height: '55%',
    backgroundColor: '#15112c',
    borderTopLeftRadius: radius.lg,
    borderTopRightRadius: radius.lg,
    padding: space.md,
    gap: space.sm,
  },
  search: {
    color: colors.text,
    backgroundColor: 'rgba(255,255,255,0.07)',
    borderRadius: radius.md,
    paddingHorizontal: space.md,
    paddingVertical: 10,
    fontSize: 15,
  },
  tabs: { flexDirection: 'row', justifyContent: 'space-between' },
  tab: { padding: 6, borderRadius: radius.sm, opacity: 0.55 },
  tabOn: { opacity: 1, backgroundColor: 'rgba(255,255,255,0.1)' },
  tabEmoji: { fontSize: 20 },
  cell: { flex: 1 / 8, aspectRatio: 1, alignItems: 'center', justifyContent: 'center' },
  cellEmoji: { fontSize: 28 },
});