import { useEffect, useState } from "react";
import { FlatList, Pressable, View } from "react-native";
import * as Haptics from "expo-haptics";
import { Link, router } from "expo-router";
import FullPageError from "@/components/FullPageError";
import ChevronRight from "@/components/ui/ChevronRight";
import CustomSafeAreaView from "@/components/ui/CustomSafeAreaView";
import FullPageSpinner from "@/components/ui/FullPageSpinner";
import PageTitle from "@/components/ui/PageTitle";
import { Text } from "@/components/ui/Text";
import { api } from "@/lib/trpc";
import { useColorScheme } from "@/lib/useColorScheme";
import { condProps } from "@/lib/utils";
import { Plus } from "lucide-react-native";

import { useBookmarkLists } from "@karakeep/shared-react/hooks/lists";
import { ZBookmarkListTreeNode } from "@karakeep/shared/utils/listUtils";

function HeaderRight({ openNewListModal }: { openNewListModal: () => void }) {
  return (
    <Pressable
      className="my-auto px-4"
      onPress={() => {
        Haptics.selectionAsync();
        openNewListModal();
      }}
    >
      <Plus color="rgb(0, 122, 255)" />
    </Pressable>
  );
}

interface ListLink {
  id: string;
  logo: string;
  name: string;
  href: string;
  level: number;
  parent?: string;
  numChildren: number;
  collapsed: boolean;
}

function traverseTree(
  node: ZBookmarkListTreeNode,
  links: ListLink[],
  showChildrenOf: Record<string, boolean>,
  parent?: string,
  level = 0,
) {
  links.push({
    id: node.item.id,
    logo: node.item.icon,
    name: node.item.name,
    href: `/dashboard/lists/${node.item.id}`,
    level,
    parent,
    numChildren: node.children?.length ?? 0,
    collapsed: !showChildrenOf[node.item.id],
  });

  if (node.children && showChildrenOf[node.item.id]) {
    node.children.forEach((child) =>
      traverseTree(child, links, showChildrenOf, node.item.id, level + 1),
    );
  }
}

export default function Lists() {
  const { colors } = useColorScheme();
  const [refreshing, setRefreshing] = useState(false);
  const { data: lists, isPending, error, refetch } = useBookmarkLists();
  const [showChildrenOf, setShowChildrenOf] = useState<Record<string, boolean>>(
    {},
  );
  const apiUtils = api.useUtils();

  useEffect(() => {
    setRefreshing(isPending);
  }, [isPending]);

  if (error) {
    return <FullPageError error={error.message} onRetry={() => refetch()} />;
  }

  if (!lists) {
    return <FullPageSpinner />;
  }

  const onRefresh = () => {
    apiUtils.lists.list.invalidate();
  };

  const links: ListLink[] = [
    {
      id: "fav",
      logo: "⭐️",
      name: "Favourites",
      href: "/dashboard/favourites",
      level: 0,
      numChildren: 0,
      collapsed: false,
    },
    {
      id: "arch",
      logo: "🗄️",
      name: "Archive",
      href: "/dashboard/archive",
      level: 0,
      numChildren: 0,
      collapsed: false,
    },
  ];

  Object.values(lists.root).forEach((list) =>
    traverseTree(list, links, showChildrenOf),
  );

  return (
    <CustomSafeAreaView>
      <FlatList
        className="h-full"
        ListHeaderComponent={
          <View className="flex flex-row justify-between">
            <PageTitle title="Lists" />
            <HeaderRight
              openNewListModal={() => router.push("/dashboard/lists/new")}
            />
          </View>
        }
        contentContainerStyle={{
          gap: 5,
        }}
        renderItem={(l) => (
          <View
            className="mx-2 flex flex-row items-center rounded-xl border border-input bg-card px-4 py-2"
            style={condProps({
              condition: l.item.level > 0,
              props: { marginLeft: l.item.level * 20 },
            })}
          >
            {l.item.numChildren > 0 && (
              <Pressable
                className="pr-2"
                onPress={() => {
                  setShowChildrenOf((prev) => ({
                    ...prev,
                    [l.item.id]: !prev[l.item.id],
                  }));
                }}
              >
                <ChevronRight
                  color={colors.foreground}
                  style={{
                    transform: [
                      { rotate: l.item.collapsed ? "0deg" : "90deg" },
                    ],
                  }}
                />
              </Pressable>
            )}

            <Link asChild key={l.item.id} href={l.item.href} className="flex-1">
              <Pressable className="flex flex-row justify-between">
                <Text>
                  {l.item.logo} {l.item.name}
                </Text>
                <ChevronRight />
              </Pressable>
            </Link>
          </View>
        )}
        data={links}
        refreshing={refreshing}
        onRefresh={onRefresh}
      />
    </CustomSafeAreaView>
  );
}