import { dbGlobal } from "drizzle-pkg/lib/db";
import {
  cards,
  cardImages,
  cardTags,
  tags,
  categories,
  favorites,
  articleCards,
  articles,
  type CardType,
  CardTypes,
} from "drizzle-pkg/lib/schema/content";
import { eq, desc, asc, and, or, like, sql, inArray } from "drizzle-orm";

export { type CardType, CardTypes };

// ============ Types ============
export interface CardImageData {
  id: number;
  url: string;
  sortOrder: number;
}

export interface TagData {
  id: number;
  name: string;
  slug: string;
}

export interface ArticleRef {
  id: number;
  title: string;
}

export interface CardWithRelations {
  id: number;
  type: CardType;
  title: string;
  description: string | null;
  content: string | null;
  aspectRatio: number | null;
  categoryId: string | null;
  createdAt: Date;
  updatedAt: Date;
  images: CardImageData[];
  tags: TagData[];
  articles: ArticleRef[];
  isFavorited?: boolean;
}

export interface CreateCardInput {
  type: CardType;
  title: string;
  description?: string | null;
  content?: string | null;
  aspectRatio?: number | null;
  categoryId?: string | null;
  images?: { url: string; sortOrder?: number }[] | null;
  tagIds?: number[] | null;
  articleIds?: number[] | null;
}

export interface UpdateCardInput {
  type?: CardType;
  title?: string;
  description?: string | null;
  content?: string | null;
  aspectRatio?: number | null;
  categoryId?: string | null;
  images?: { url: string; sortOrder?: number }[] | null;
  tagIds?: number[] | null;
  articleIds?: number[] | null;
}

export interface ListCardsOptions {
  page?: number;
  pageSize?: number;
  categoryId?: string;
  tagId?: number;
  type?: CardType;
  q?: string;
  favorited?: boolean;
  userId?: number;
}

// ============ Helpers ============
function now() {
  return new Date();
}

async function incrCategoryCount(categoryId: string | null, delta: number) {
  if (!categoryId) return
  const [row] = await dbGlobal
    .select({ count: categories.count })
    .from(categories)
    .where(eq(categories.id, categoryId))
    .limit(1)
  if (!row) return
  await dbGlobal
    .update(categories)
    .set({ count: Math.max(0, row.count + delta) })
    .where(eq(categories.id, categoryId))
}

// ============ CRUD ============

export async function listCards(
  opts: ListCardsOptions,
): Promise<{ items: CardWithRelations[]; total: number; page: number; pageSize: number; hasMore: boolean }> {
  const page = opts.page ?? 1;
  const pageSize = opts.pageSize ?? 12;

  const conditions = [];
  if (opts.categoryId === '__uncategorized__') {
    conditions.push(sql`${cards.categoryId} IS NULL`);
  } else if (opts.categoryId) {
    conditions.push(eq(cards.categoryId, opts.categoryId));
  }
  if (opts.type) conditions.push(eq(cards.type, opts.type));

  // search
  if (opts.q) {
    const term = `%${opts.q}%`
    conditions.push(
      or(
        like(cards.title, term),
        like(cards.description, term),
        like(cards.content, term),
      )!
    )
  }

  // tag filter: find card IDs that have this tag, then filter
  let tagCardIds: number[] | null = null;
  if (opts.tagId) {
    const tagRows = await dbGlobal
      .select({ cardId: cardTags.cardId })
      .from(cardTags)
      .where(eq(cardTags.tagId, opts.tagId));
    tagCardIds = tagRows.map((r) => r.cardId);
    if (tagCardIds.length === 0) {
      return { items: [], total: 0, page, pageSize, hasMore: false };
    }
    conditions.push(inArray(cards.id, tagCardIds));
  }

  // favorites filter (requires authenticated user)
  if (opts.favorited && opts.userId) {
    const favCardIds = await dbGlobal
      .select({ cardId: favorites.cardId })
      .from(favorites)
      .where(eq(favorites.userId, opts.userId));
    const favIds = favCardIds.map((r) => r.cardId);
    if (favIds.length === 0) {
      return { items: [], total: 0, page, pageSize, hasMore: false };
    }
    conditions.push(inArray(cards.id, favIds));
  }

  const where = conditions.length > 0 ? and(...conditions) : undefined;

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

  const total = countResult[0]?.count ?? 0;

  // Load relations for this page
  const cardIds = rows.map((r) => r.id);
  const [allImages, allCardTags] = await Promise.all([
    cardIds.length > 0
      ? dbGlobal
          .select()
          .from(cardImages)
          .where(inArray(cardImages.cardId, cardIds))
          .orderBy(asc(cardImages.sortOrder))
      : Promise.resolve([]),
    cardIds.length > 0
      ? dbGlobal
          .select()
          .from(cardTags)
          .where(inArray(cardTags.cardId, cardIds))
      : Promise.resolve([]),
  ]);

  // Load favorite status for current user
  let favoritedSet = new Set<number>();
  if (opts.userId && cardIds.length > 0) {
    const favRows = await dbGlobal
      .select({ cardId: favorites.cardId })
      .from(favorites)
      .where(
        and(
          eq(favorites.userId, opts.userId),
          inArray(favorites.cardId, cardIds),
        ),
      );
    favoritedSet = new Set(favRows.map((r) => r.cardId));
  }

  // Load referenced tags
  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, CardImageData[]>();
  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, TagData[]>();
  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.map((row) => ({
    id: row.id,
    type: row.type as CardType,
    title: row.title,
    description: row.description,
    content: row.content,
    aspectRatio: row.aspectRatio,
    categoryId: row.categoryId,
    createdAt: row.createdAt,
    updatedAt: row.updatedAt,
    images: imagesByCard.get(row.id) ?? [],
    tags: tagsByCard.get(row.id) ?? [],
    articles: [],
    isFavorited: opts.userId ? favoritedSet.has(row.id) : undefined,
  }));

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

export async function getCardById(id: number): Promise<CardWithRelations | null> {
  const rows = await dbGlobal
    .select()
    .from(cards)
    .where(eq(cards.id, id))
    .limit(1);

  const row = rows[0];
  if (!row) return null;

  const [images, cardTagRows, articleCardRows] = await Promise.all([
    dbGlobal
      .select()
      .from(cardImages)
      .where(eq(cardImages.cardId, id))
      .orderBy(asc(cardImages.sortOrder)),
    dbGlobal.select().from(cardTags).where(eq(cardTags.cardId, id)),
    dbGlobal.select().from(articleCards).where(eq(articleCards.cardId, id)),
  ]);

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

  const articleIds = articleCardRows.map((ac) => ac.articleId);
  const articleRows =
    articleIds.length > 0
      ? await dbGlobal
          .select({ id: articles.id, title: articles.title })
          .from(articles)
          .where(inArray(articles.id, articleIds))
      : [];

  return {
    id: row.id,
    type: row.type as CardType,
    title: row.title,
    description: row.description,
    content: row.content,
    aspectRatio: row.aspectRatio,
    categoryId: row.categoryId,
    createdAt: row.createdAt,
    updatedAt: row.updatedAt,
    images: images.map((img) => ({
      id: img.id,
      url: img.url,
      sortOrder: img.sortOrder,
    })),
    tags: tagRows.map((t) => ({
      id: t.id,
      name: t.name,
      slug: t.slug,
    })),
    articles: articleRows.map((a) => ({
      id: a.id,
      title: a.title,
    })),
  };
}

export async function createCard(input: CreateCardInput): Promise<CardWithRelations> {
  const [inserted] = await dbGlobal
    .insert(cards)
    .values({
      type: input.type,
      title: input.title,
      description: input.description ?? null,
      content: input.content ?? null,
      aspectRatio: input.aspectRatio ?? null,
      categoryId: input.categoryId ?? null,
    })
    .returning({ id: cards.id });

  if (!inserted) throw new Error("Failed to create card");
  const cardId = inserted.id;

  // Insert images
  if (input.images && input.images.length > 0) {
    await dbGlobal.insert(cardImages).values(
      input.images.map((img, i) => ({
        cardId,
        url: img.url,
        sortOrder: img.sortOrder ?? i,
      })),
    );
  }

  // Insert tag associations
  if (input.tagIds && input.tagIds.length > 0) {
    await dbGlobal.insert(cardTags).values(
      input.tagIds.map((tagId) => ({
        cardId,
        tagId,
      })),
    );
  }

  // Insert article associations
  if (input.articleIds && input.articleIds.length > 0) {
    await dbGlobal.insert(articleCards).values(
      input.articleIds.map((articleId, i) => ({
        articleId,
        cardId,
        sortOrder: i,
      })),
    );
  }

  // Update category count
  if (input.categoryId) {
    await incrCategoryCount(input.categoryId, 1)
  }

  return (await getCardById(cardId))!;
}

export async function updateCard(
  id: number,
  input: UpdateCardInput,
): Promise<CardWithRelations | null> {
  const existing = await getCardById(id);
  if (!existing) return null;

  const oldCatId = existing.categoryId

  await dbGlobal
    .update(cards)
    .set({
      ...(input.type !== undefined && { type: input.type }),
      ...(input.title !== undefined && { title: input.title }),
      ...(input.description !== undefined && { description: input.description }),
      ...(input.content !== undefined && { content: input.content }),
      ...(input.aspectRatio !== undefined && { aspectRatio: input.aspectRatio }),
      ...(input.categoryId !== undefined && { categoryId: input.categoryId }),
      updatedAt: now(),
    })
    .where(eq(cards.id, id));

  // Update category counts if category changed
  if (input.categoryId !== undefined && input.categoryId !== oldCatId) {
    if (oldCatId) await incrCategoryCount(oldCatId, -1)
    if (input.categoryId) await incrCategoryCount(input.categoryId, 1)
  }

  // Replace images if provided
  if (input.images !== undefined) {
    await dbGlobal.delete(cardImages).where(eq(cardImages.cardId, id));
    if (input.images !== null && input.images.length > 0) {
      await dbGlobal.insert(cardImages).values(
        input.images.map((img, i) => ({
          cardId: id,
          url: img.url,
          sortOrder: img.sortOrder ?? i,
        })),
      );
    }
  }

  // Replace tags if provided
  if (input.tagIds !== undefined) {
    await dbGlobal.delete(cardTags).where(eq(cardTags.cardId, id));
    if (input.tagIds !== null && input.tagIds.length > 0) {
      await dbGlobal.insert(cardTags).values(
        input.tagIds.map((tagId) => ({
          cardId: id,
          tagId,
        })),
      );
    }
  }

  // Replace article associations if provided
  if (input.articleIds !== undefined) {
    await dbGlobal.delete(articleCards).where(eq(articleCards.cardId, id));
    if (input.articleIds !== null && input.articleIds.length > 0) {
      await dbGlobal.insert(articleCards).values(
        input.articleIds.map((articleId, i) => ({
          articleId,
          cardId: id,
          sortOrder: i,
        })),
      );
    }
  }

  return getCardById(id);
}

export async function deleteCard(id: number) {
  // Get category before deleting (for count update)
  const [row] = await dbGlobal
    .select({ categoryId: cards.categoryId })
    .from(cards)
    .where(eq(cards.id, id))
    .limit(1)

  // Clean up related records
  await dbGlobal.delete(cardImages).where(eq(cardImages.cardId, id));
  await dbGlobal.delete(cardTags).where(eq(cardTags.cardId, id));
  await dbGlobal.delete(articleCards).where(eq(articleCards.cardId, id));
  await dbGlobal.delete(favorites).where(eq(favorites.cardId, id));
  await dbGlobal.delete(cards).where(eq(cards.id, id));

  // Decrement category count
  if (row?.categoryId) {
    await incrCategoryCount(row.categoryId, -1)
  }
}