import { dbGlobal } from "drizzle-pkg/lib/db";
import { favorites, cards, cardImages, cardTags, tags } from "drizzle-pkg/lib/schema/content";
import { eq, and, inArray, desc, sql, asc } from "drizzle-orm";
import type { CardWithRelations } from "../card";

// ============ Types ============

export interface ListFavoritesOptions {
  page?: number
  pageSize?: number
}

// ============ Toggle ============

/**
 * Toggle favorite status for a card.
 * Returns the new favorited state.
 */
export async function toggleFavorite(
  userId: number,
  cardId: number,
): Promise<{ favorited: boolean }> {
  const [existing] = await dbGlobal
    .select()
    .from(favorites)
    .where(
      and(
        eq(favorites.userId, userId),
        eq(favorites.cardId, cardId),
      ),
    )
    .limit(1);

  if (existing) {
    await dbGlobal
      .delete(favorites)
      .where(
        and(
          eq(favorites.userId, userId),
          eq(favorites.cardId, cardId),
        ),
      );
    return { favorited: false };
  }

  await dbGlobal.insert(favorites).values({
    userId,
    cardId,
  });
  return { favorited: true };
}

// ============ Batch check ============

/**
 * Given a list of card IDs, return which ones the user has favorited.
 */
export async function batchIsFavorited(
  userId: number,
  cardIds: number[],
): Promise<Set<number>> {
  if (cardIds.length === 0) return new Set();

  const rows = await dbGlobal
    .select({ cardId: favorites.cardId })
    .from(favorites)
    .where(
      and(
        eq(favorites.userId, userId),
        inArray(favorites.cardId, cardIds),
      ),
    );

  return new Set(rows.map((r) => r.cardId));
}

// ============ List ============

/**
 * List favorited card IDs for a user.
 */
export async function listFavoriteCardIds(
  userId: number,
  opts: ListFavoritesOptions = {},
): Promise<{ cardIds: number[]; total: number }> {
  const page = opts.page ?? 1;
  const pageSize = opts.pageSize ?? 12;

  const [rows, countResult] = await Promise.all([
    dbGlobal
      .select({ cardId: favorites.cardId })
      .from(favorites)
      .where(eq(favorites.userId, userId))
      .orderBy(desc(favorites.createdAt))
      .limit(pageSize)
      .offset((page - 1) * pageSize),
    dbGlobal
      .select({ count: sql<number>`count(*)` })
      .from(favorites)
      .where(eq(favorites.userId, userId)),
  ]);

  return {
    cardIds: rows.map((r) => r.cardId),
    total: countResult[0]?.count ?? 0,
  };
}

/**
 * List favorited cards with full card data.
 */
export async function listFavoriteCards(
  userId: number,
  opts: ListFavoritesOptions = {},
): Promise<{ items: CardWithRelations[]; total: number; page: number; pageSize: number; hasMore: boolean }> {
  const page = opts.page ?? 1;
  const pageSize = opts.pageSize ?? 12;

  const { cardIds, total } = await listFavoriteCardIds(userId, { page, pageSize });

  if (cardIds.length === 0) {
    return { items: [], total, page, pageSize, hasMore: false };
  }

  // Fetch full card data via existing listCards with id filter
  // Build a simple query with the IDs
  const rows = await dbGlobal
    .select()
    .from(cards)
    .where(inArray(cards.id, cardIds))
    .orderBy(desc(cards.createdAt));

  // Load relations
  const allImages = await dbGlobal
    .select()
    .from(cardImages)
    .where(inArray(cardImages.cardId, cardIds));

  const allCardTags = await dbGlobal
    .select()
    .from(cardTags)
    .where(inArray(cardTags.cardId, cardIds));

  const tagIds = [...new Set(allCardTags.map((ct) => ct.tagId))];
  const tagRows =
    tagIds.length > 0
      ? await dbGlobal.select().from(tags).where(inArray(tags.id, tagIds))
      : [];

  const tagMap = new Map(tagRows.map((t) => [t.id, t]));
  const imagesByCard = new Map<number, { id: number; url: string; sortOrder: number }[]>();
  for (const img of allImages) {
    if (!imagesByCard.has(img.cardId)) imagesByCard.set(img.cardId, []);
    imagesByCard.get(img.cardId)!.push({
      id: img.id,
      url: img.url,
      sortOrder: img.sortOrder,
    });
  }
  const tagsByCard = new Map<number, { id: number; name: string; slug: string }[]>();
  for (const ct of allCardTags) {
    const tag = tagMap.get(ct.tagId);
    if (!tag) continue;
    if (!tagsByCard.has(ct.cardId)) tagsByCard.set(ct.cardId, []);
    tagsByCard.get(ct.cardId)!.push({
      id: tag.id,
      name: tag.name,
      slug: tag.slug,
    });
  }

  const items: CardWithRelations[] = rows
    .filter((row) => cardIds.includes(row.id))
    .sort((a, b) => cardIds.indexOf(a.id) - cardIds.indexOf(b.id))
    .map((row) => ({
      id: row.id,
      type: row.type as CardWithRelations["type"],
      title: row.title,
      description: row.description,
      aspectRatio: row.aspectRatio,
      categoryId: row.categoryId,
      createdAt: row.createdAt,
      updatedAt: row.updatedAt,
      images: imagesByCard.get(row.id) ?? [],
      tags: tagsByCard.get(row.id) ?? [],
    }));

  return {
    items,
    total,
    page,
    pageSize,
    hasMore: page * pageSize < total,
  };
}