import * as Location from "expo-location";
import { router } from "expo-router";
import { useMemo, useState } from "react";
import { Alert, Linking, ScrollView, View } from "react-native";
import { useTranslation } from "react-i18next";
import { Badge } from "@/components/ui/Badge";
import { Button } from "@/components/ui/Button";
import { Card } from "@/components/ui/Card";
import { AppHeader } from "@/components/ui/Header";
import { Screen } from "@/components/ui/Screen";
import { Text } from "@/components/ui/Text";
import { branches } from "@/lib/data/branches";
import { routes } from "@/lib/routes";
import { useLocationStore } from "@/lib/stores/locationStore";
import { colors, gutter } from "@/lib/theme";

function dist(a: { lat: number; lng: number }, b: { lat: number; lng: number }) {
  const toRad = (d: number) => (d * Math.PI) / 180;
  const R = 6371;
  const dLat = toRad(b.lat - a.lat);
  const dLng = toRad(b.lng - a.lng);
  const x =
    Math.sin(dLat / 2) ** 2 +
    Math.cos(toRad(a.lat)) * Math.cos(toRad(b.lat)) * Math.sin(dLng / 2) ** 2;
  return 2 * R * Math.asin(Math.sqrt(x));
}

export default function BranchesScreen() {
  const { t } = useTranslation();
  const setBranchId = useLocationStore((s) => s.setBranchId);
  const setFulfillment = useLocationStore((s) => s.setFulfillment);
  const setCoords = useLocationStore((s) => s.setCoords);
  const branchId = useLocationStore((s) => s.branchId);
  const [coords, setLocal] = useState<{ lat: number; lng: number } | null>(null);

  const sorted = useMemo(() => {
    if (!coords) return branches;
    return [...branches].sort((a, b) => dist(coords, a) - dist(coords, b));
  }, [coords]);

  const useMyLocation = async () => {
    const { status } = await Location.requestForegroundPermissionsAsync();
    if (status !== "granted") {
      Alert.alert("Location", "Permission denied");
      return;
    }
    const pos = await Location.getCurrentPositionAsync({});
    const c = { lat: pos.coords.latitude, lng: pos.coords.longitude };
    setLocal(c);
    setCoords(c.lat, c.lng);
  };

  return (
    <Screen>
      <AppHeader
        title={t("common.branches")}
        subtitle={`${branches.length} locations across Addis Ababa`}
      />
      <ScrollView
        contentContainerStyle={{
          paddingHorizontal: gutter,
          paddingBottom: 40,
          gap: 12,
        }}
      >
        <Button
          title={t("common.useLocation")}
          icon="navigate-outline"
          onPress={useMyLocation}
        />
        <Text variant="h3">{t("common.nearestBranch")}</Text>

        {sorted.map((b, index) => {
          const selected = branchId === b.id;
          const km = coords ? dist(coords, b) : null;
          return (
            <Card
              key={b.id}
              style={{
                borderWidth: selected ? 2 : 1,
                borderColor: selected ? colors.brand : colors.line,
              }}
            >
              <View style={{ flexDirection: "row", justifyContent: "space-between", gap: 10 }}>
                <View style={{ flex: 1 }}>
                  <Text variant="h3">{b.name}</Text>
                  <Text variant="bodySm" color={colors.muted} style={{ marginTop: 4 }}>
                    {b.area}
                  </Text>
                  <Text variant="caption" color={colors.subtle} style={{ marginTop: 2 }}>
                    {b.hours}
                    {b.pickupAvailable ? " · Pickup" : ""}
                  </Text>
                </View>
                <View style={{ alignItems: "flex-end", gap: 6 }}>
                  {selected ? <Badge label="Selected" tone="brand" /> : null}
                  {index === 0 && coords ? <Badge label="Nearest" tone="info" /> : null}
                  {km != null ? (
                    <Text variant="label" color={colors.brandText}>
                      {km.toFixed(1)} km
                    </Text>
                  ) : null}
                </View>
              </View>

              <View style={{ flexDirection: "row", flexWrap: "wrap", gap: 8, marginTop: 14 }}>
                <Button
                  title="Call"
                  size="md"
                  fullWidth={false}
                  variant="outline"
                  icon="call-outline"
                  onPress={() => Linking.openURL(`tel:${b.phone}`)}
                />
                <Button
                  title="Maps"
                  size="md"
                  fullWidth={false}
                  variant="outline"
                  icon="map-outline"
                  onPress={() => Linking.openURL(b.mapsUrl)}
                />
                <Button
                  title="Set pickup"
                  size="md"
                  fullWidth={false}
                  onPress={() => {
                    setBranchId(b.id);
                    setFulfillment("pickup");
                    Alert.alert("Pickup set", `${b.name} selected for checkout.`);
                  }}
                />
              </View>
            </Card>
          );
        })}

        <Button
          title="Go to checkout"
          variant="ghost"
          onPress={() => router.push(routes.checkout)}
        />
      </ScrollView>
    </Screen>
  );
}