import { createSupabaseServiceRoleClient } from "@/lib/supabase/service-role";
import {
    getFavoritePhotoIds,
    mapPublicGalleryPhoto,
} from "@/server/site/gallery-photos";
import type { CollectionPhoto } from "@/types/admin/collection";

type PublicCollectionRow = {
    id: string;
    title: string;
    slug: string;
    description: string | null;
    cover_photo_id: string | null;
    published_at: string | null;
    created_at: string;
};

type CollectionItemRow = {
    photo_id: string;
    sort_order: number;
};

const collectionSelect =
    "id,title,slug,description,cover_photo_id,published_at,created_at";

const photoSelect =
    "id,unsplash_id,slug,description,alt_description,width,height,color,color_family,likes,urls,user_info,photo_created_at,picked_at,oss_url";

function getPhotoUrl(photo: CollectionPhoto | null) {
    if (!photo) {
        return null;
    }

    const urls = photo.urls as Record<string, string> | undefined;
    return (
        photo.oss_url ??
        urls?.regular ??
        urls?.small ??
        urls?.raw ??
        urls?.thumb ??
        null
    );
}

async function getPhotosById(photoIds: string[]) {
    if (photoIds.length === 0) {
        return new Map<string, CollectionPhoto>();
    }

    const supabase = createSupabaseServiceRoleClient();
    const { data, error } = await supabase
        .from("wg_gallery_photos")
        .select(photoSelect)
        .eq("is_picked", true)
        .in("id", photoIds);

    if (error) {
        throw error;
    }

    return new Map(
        ((data ?? []) as CollectionPhoto[]).map((photo) => [photo.id, photo]),
    );
}

export async function listPublishedCollections({
    page,
    pageSize,
    userId,
}: {
    page: number;
    pageSize: number;
    userId: string | null;
}) {
    const supabase = createSupabaseServiceRoleClient();
    const { data, error, count } = await supabase
        .from("wg_photo_collections")
        .select(collectionSelect, { count: "exact" })
        .eq("is_published", true)
        .order("published_at", { ascending: false, nullsFirst: false })
        .order("created_at", { ascending: false })
        .range((page - 1) * pageSize, page * pageSize - 1);

    if (error) {
        throw error;
    }

    const collections = (data ?? []) as PublicCollectionRow[];
    const collectionIds = collections.map((collection) => collection.id);
    const coverPhotoIds = collections
        .map((collection) => collection.cover_photo_id)
        .filter((id): id is string => Boolean(id));

    const { data: items, error: itemsError } =
        collectionIds.length > 0
            ? await supabase
                  .from("wg_photo_collection_items")
                  .select("collection_id,photo_id")
                  .in("collection_id", collectionIds)
            : { data: [], error: null };

    if (itemsError) {
        throw itemsError;
    }

    const photosById = await getPhotosById(coverPhotoIds);
    const favoritePhotoIds = await getFavoritePhotoIds({
        userId,
        photoIds: coverPhotoIds,
    });
    const itemRows = (items ?? []) as Array<{
        collection_id: string;
        photo_id: string;
    }>;
    const countByCollection = itemRows.reduce(
        (counts, item) => {
            counts[item.collection_id] = (counts[item.collection_id] ?? 0) + 1;
            return counts;
        },
        {} as Record<string, number>,
    );

    return {
        data: collections.map((collection) => {
            const coverPhoto = collection.cover_photo_id
                ? (photosById.get(collection.cover_photo_id) ?? null)
                : null;

            return {
                id: collection.id,
                title: collection.title,
                slug: collection.slug,
                description: collection.description,
                coverPhoto: coverPhoto
                    ? mapPublicGalleryPhoto({
                          photo: coverPhoto,
                          favoritePhotoIds,
                      })
                    : null,
                coverUrl: getPhotoUrl(coverPhoto),
                photoCount: countByCollection[collection.id] ?? 0,
                publishedAt: collection.published_at,
            };
        }),
        total: count ?? 0,
    };
}

export async function getPublishedCollectionBySlug({
    page,
    pageSize,
    slug,
    userId,
}: {
    page: number;
    pageSize: number;
    slug: string;
    userId: string | null;
}) {
    const supabase = createSupabaseServiceRoleClient();
    const { data: collection, error } = await supabase
        .from("wg_photo_collections")
        .select(collectionSelect)
        .eq("slug", slug)
        .eq("is_published", true)
        .maybeSingle<PublicCollectionRow>();

    if (error) {
        throw error;
    }

    if (!collection) {
        return null;
    }

    const {
        data: items,
        error: itemsError,
        count,
    } = await supabase
        .from("wg_photo_collection_items")
        .select("photo_id,sort_order", { count: "exact" })
        .eq("collection_id", collection.id)
        .order("sort_order", { ascending: true })
        .order("created_at", { ascending: true })
        .range((page - 1) * pageSize, page * pageSize - 1);

    if (itemsError) {
        throw itemsError;
    }

    const itemRows = (items ?? []) as CollectionItemRow[];
    const photoIds = [
        ...itemRows.map((item) => item.photo_id),
        ...(collection.cover_photo_id ? [collection.cover_photo_id] : []),
    ];
    const photosById = await getPhotosById(Array.from(new Set(photoIds)));
    const favoritePhotoIds = await getFavoritePhotoIds({
        userId,
        photoIds,
    });
    const coverPhoto = collection.cover_photo_id
        ? (photosById.get(collection.cover_photo_id) ?? null)
        : null;

    return {
        collection: {
            id: collection.id,
            title: collection.title,
            slug: collection.slug,
            description: collection.description,
            coverPhoto: coverPhoto
                ? mapPublicGalleryPhoto({ photo: coverPhoto, favoritePhotoIds })
                : null,
            coverUrl: getPhotoUrl(coverPhoto),
            photoCount: count ?? 0,
            publishedAt: collection.published_at,
        },
        photos: itemRows
            .map((item) => photosById.get(item.photo_id))
            .filter((photo): photo is CollectionPhoto => Boolean(photo))
            .map((photo) => mapPublicGalleryPhoto({ photo, favoritePhotoIds })),
        total: count ?? 0,
    };
}