import { z } from "zod";
import { and, eq, desc, exists } from "drizzle-orm";
import {
  userFavorites,
  objects,
  workspaces,
  workspaceMembers,
} from "@tasks/database/schema";
import { router, protectedProcedure } from "@/server/trpc";
import { TRPCError } from "@trpc/server";

/**
 * Confirm the caller can see the given object. Cross-workspace favorites
 * shouldn't expose object ids the user has no business reading.
 */
async function assertCallerCanSeeObject(
  db: typeof import("@tasks/database").db,
  objectId: string,
  userId: string,
): Promise<void> {
  const [row] = await db
    .select({
      id: objects.id,
      workspaceId: objects.workspaceId,
      ownerUserId: workspaces.ownerUserId,
    })
    .from(objects)
    .innerJoin(workspaces, eq(objects.workspaceId, workspaces.id))
    .where(eq(objects.id, objectId))
    .limit(1);
  if (!row) {
    throw new TRPCError({ code: "NOT_FOUND", message: "Object not found" });
  }
  if (row.ownerUserId === userId) return;
  const [member] = await db
    .select({ id: workspaceMembers.id })
    .from(workspaceMembers)
    .where(
      and(
        eq(workspaceMembers.workspaceId, row.workspaceId),
        eq(workspaceMembers.userId, userId),
      ),
    )
    .limit(1);
  if (!member) {
    throw new TRPCError({ code: "NOT_FOUND", message: "Object not found" });
  }
}

export const favoritesRouter = router({
  list: protectedProcedure.query(async ({ ctx }) => {
    const rows = await ctx.db
      .select({
        id: userFavorites.id,
        objectId: userFavorites.objectId,
        createdAt: userFavorites.createdAt,
        objectTitle: objects.title,
        objectType: objects.type,
        objectIcon: objects.icon,
        workspaceId: objects.workspaceId,
      })
      .from(userFavorites)
      .innerJoin(objects, eq(userFavorites.objectId, objects.id))
      .where(eq(userFavorites.userId, ctx.session.user.id))
      .orderBy(desc(userFavorites.createdAt));
    return rows;
  }),

  toggle: protectedProcedure
    .input(z.object({ objectId: z.string().uuid() }))
    .mutation(async ({ ctx, input }) => {
      await assertCallerCanSeeObject(ctx.db, input.objectId, ctx.session.user.id);

      const existing = await ctx.db
        .select({ id: userFavorites.id })
        .from(userFavorites)
        .where(
          and(
            eq(userFavorites.userId, ctx.session.user.id),
            eq(userFavorites.objectId, input.objectId),
          ),
        )
        .limit(1);

      if (existing.length > 0) {
        await ctx.db.delete(userFavorites).where(eq(userFavorites.id, existing[0].id));
        return { favorited: false };
      }

      await ctx.db.insert(userFavorites).values({
        userId: ctx.session.user.id,
        objectId: input.objectId,
      });
      return { favorited: true };
    }),

  isFavorited: protectedProcedure
    .input(z.object({ objectId: z.string().uuid() }))
    .query(async ({ ctx, input }) => {
      const rows = await ctx.db
        .select({ id: userFavorites.id })
        .from(userFavorites)
        .where(
          and(
            eq(userFavorites.userId, ctx.session.user.id),
            eq(userFavorites.objectId, input.objectId),
          ),
        )
        .limit(1);
      return { favorited: rows.length > 0 };
    }),
});