import { useLocalSearchParams, useRouter } from 'expo-router';
import { Pressable, ScrollView, StyleSheet, Text, View } from 'react-native';
import { useActivity } from '@/db/queries';

export default function ActivityScreen() {
  const { id } = useLocalSearchParams<{ id: string }>();
  const router = useRouter();
  const row = useActivity(id);

  if (!row) {
    return (
      <View style={styles.center}>
        <Text style={styles.notFound}>Activity not found</Text>
      </View>
    );
  }

  const detail = JSON.parse(row.detail_json);
  const km = detail.distance_m != null
    ? (detail.distance_m / 1000).toFixed(2)
    : null;
  const elev = detail.elevation_gain_m != null
    ? Math.round(detail.elevation_gain_m)
    : null;
  const elevLoss = detail.elevation_loss_m != null
    ? Math.round(Math.abs(detail.elevation_loss_m))
    : null;
  const movingTime = detail.moving_time_s != null
    ? formatDuration(detail.moving_time_s)
    : null;
  const speed = detail.avg_speed_kmh != null
    ? detail.avg_speed_kmh.toFixed(1)
    : null;
  const hr = detail.avg_hr_bpm != null
    ? Math.round(detail.avg_hr_bpm)
    : null;
  const power = detail.avg_power_w != null
    ? Math.round(detail.avg_power_w)
    : null;

  const date = new Date(detail.started_at).toLocaleDateString(undefined, {
    weekday: 'long', day: 'numeric', month: 'long', year: 'numeric',
  });

  return (
    <ScrollView style={styles.container} contentContainerStyle={styles.content}>
      <Pressable style={styles.backButton} onPress={() => router.back()}>
        <Text style={styles.backText}>← Back</Text>
      </Pressable>

      <Text style={styles.sport}>{detail.sport ?? 'Activity'}</Text>
      <Text style={styles.title}>{detail.title}</Text>
      <Text style={styles.date}>{date}</Text>

      {/* Map placeholder — Phase 1 */}
      <View style={styles.mapPlaceholder}>
        <Text style={styles.mapPlaceholderText}>Map · Phase 1</Text>
      </View>

      {/* Stats grid */}
      <View style={styles.grid}>
        {km && <StatCell label="Distance" value={km} unit="km" />}
        {movingTime && <StatCell label="Moving time" value={movingTime} unit="" />}
        {elev != null && <StatCell label="Elevation gain" value={String(elev)} unit="m" />}
        {elevLoss != null && <StatCell label="Elevation loss" value={String(elevLoss)} unit="m" />}
        {speed && <StatCell label="Avg speed" value={speed} unit="km/h" />}
        {hr && <StatCell label="Avg HR" value={String(hr)} unit="bpm" />}
        {power && <StatCell label="Avg power" value={String(power)} unit="W" />}
      </View>

      {/* Elevation chart placeholder — Phase 1 */}
      {row.timeseries_json && (
        <View style={styles.chartPlaceholder}>
          <Text style={styles.mapPlaceholderText}>Elevation chart · Phase 1</Text>
        </View>
      )}

      <View style={styles.meta}>
        <MetaRow label="Source" value={detail.source ?? '—'} />
        <MetaRow label="Device" value={detail.device ?? '—'} />
        <MetaRow label="Origin" value={row.origin} />
        <MetaRow label="Synced" value={row.synced_at ? new Date(row.synced_at * 1000).toLocaleDateString() : 'No'} />
      </View>
    </ScrollView>
  );
}

function StatCell({ label, value, unit }: { label: string; value: string; unit: string }) {
  return (
    <View style={styles.statCell}>
      <View style={styles.statValueRow}>
        <Text style={styles.statValue}>{value}</Text>
        {unit ? <Text style={styles.statUnit}>{unit}</Text> : null}
      </View>
      <Text style={styles.statLabel}>{label}</Text>
    </View>
  );
}

function MetaRow({ label, value }: { label: string; value: string }) {
  return (
    <View style={styles.metaRow}>
      <Text style={styles.metaLabel}>{label}</Text>
      <Text style={styles.metaValue}>{value}</Text>
    </View>
  );
}

function formatDuration(seconds: number): string {
  const h = Math.floor(seconds / 3600);
  const m = Math.floor((seconds % 3600) / 60);
  const s = seconds % 60;
  if (h > 0) return `${h}:${String(m).padStart(2, '0')}:${String(s).padStart(2, '0')}`;
  return `${m}:${String(s).padStart(2, '0')}`;
}

const styles = StyleSheet.create({
  container: { flex: 1, backgroundColor: '#09090b' },
  content: { paddingBottom: 40 },
  center: { flex: 1, alignItems: 'center', justifyContent: 'center', backgroundColor: '#09090b' },
  notFound: { color: '#71717a', fontSize: 16 },
  backButton: { paddingHorizontal: 16, paddingTop: 60, paddingBottom: 12 },
  backText: { color: '#60a5fa', fontSize: 15 },
  sport: { color: '#71717a', fontSize: 12, fontWeight: '600', letterSpacing: 0.8, paddingHorizontal: 16, marginBottom: 4 },
  title: { color: '#f4f4f5', fontSize: 22, fontWeight: '700', paddingHorizontal: 16, marginBottom: 4 },
  date: { color: '#71717a', fontSize: 13, paddingHorizontal: 16, marginBottom: 16 },
  mapPlaceholder: {
    height: 200, backgroundColor: '#18181b',
    alignItems: 'center', justifyContent: 'center',
    borderTopWidth: 1, borderBottomWidth: 1, borderColor: '#27272a',
    marginBottom: 16,
  },
  chartPlaceholder: {
    height: 120, backgroundColor: '#18181b',
    alignItems: 'center', justifyContent: 'center',
    borderTopWidth: 1, borderBottomWidth: 1, borderColor: '#27272a',
    marginBottom: 16,
  },
  mapPlaceholderText: { color: '#3f3f46', fontSize: 13 },
  grid: {
    flexDirection: 'row', flexWrap: 'wrap',
    paddingHorizontal: 12, gap: 8, marginBottom: 16,
  },
  statCell: {
    backgroundColor: '#18181b', borderRadius: 10,
    borderWidth: 1, borderColor: '#27272a',
    padding: 14, width: '47%',
  },
  statValueRow: { flexDirection: 'row', alignItems: 'baseline', gap: 4, marginBottom: 4 },
  statValue: { color: '#f4f4f5', fontSize: 24, fontWeight: '700' },
  statUnit: { color: '#71717a', fontSize: 13 },
  statLabel: { color: '#71717a', fontSize: 12 },
  meta: {
    marginHorizontal: 16, backgroundColor: '#18181b',
    borderRadius: 10, borderWidth: 1, borderColor: '#27272a',
  },
  metaRow: {
    flexDirection: 'row', justifyContent: 'space-between',
    paddingHorizontal: 14, paddingVertical: 10,
    borderBottomWidth: 1, borderBottomColor: '#27272a',
  },
  metaLabel: { color: '#71717a', fontSize: 13 },
  metaValue: { color: '#a1a1aa', fontSize: 13 },
});