"use server";

import { revalidatePath } from "next/cache";

import { prisma } from "@/lib/db";
import { requireUserId } from "@/lib/auth-helpers";
import { GroupColorSchema, GroupTitleSchema } from "@/lib/validation/group";
import type { GroupDTO } from "@/types/board";

export async function createGroup(
  categoryId: string,
  title: string,
  color: string
): Promise<GroupDTO> {
  const userId = await requireUserId();
  const parsedTitle = GroupTitleSchema.parse(title);
  const parsedColor = GroupColorSchema.parse(color);

  const category = await prisma.category.findFirst({
    where: { id: categoryId, userId },
    select: { id: true },
  });
  if (!category) throw new Error("Category not found");

  const count = await prisma.group.count({ where: { categoryId } });

  const group = await prisma.group.create({
    data: { title: parsedTitle, color: parsedColor, order: count, categoryId },
  });

  revalidatePath("/");
  return {
    id: group.id,
    title: group.title,
    color: group.color,
    order: group.order,
    noteContent: group.noteContent,
    categoryId: group.categoryId,
    todos: [],
  };
}

export async function updateGroup(
  groupId: string,
  data: { title?: string; color?: string }
): Promise<void> {
  const userId = await requireUserId();

  const update: { title?: string; color?: string } = {};
  if (data.title !== undefined) update.title = GroupTitleSchema.parse(data.title);
  if (data.color !== undefined) update.color = GroupColorSchema.parse(data.color);

  const { count } = await prisma.group.updateMany({
    where: { id: groupId, category: { userId } },
    data: update,
  });
  if (count === 0) throw new Error("Group not found");

  revalidatePath("/");
}

export async function deleteGroup(groupId: string): Promise<void> {
  const userId = await requireUserId();

  const { count } = await prisma.group.deleteMany({
    where: { id: groupId, category: { userId } },
  });
  if (count === 0) throw new Error("Group not found");

  revalidatePath("/");
}

/** Persists a new card order within a single lane. */
export async function reorderGroupsInCategory(
  categoryId: string,
  orderedGroupIds: string[]
): Promise<void> {
  const userId = await requireUserId();

  const category = await prisma.category.findFirst({
    where: { id: categoryId, userId },
    include: { groups: { select: { id: true } } },
  });
  if (!category) throw new Error("Category not found");

  const ownedIds = new Set(category.groups.map((g) => g.id));
  if (
    orderedGroupIds.length !== ownedIds.size ||
    !orderedGroupIds.every((id) => ownedIds.has(id))
  ) {
    throw new Error("Group list does not match this category's groups");
  }

  await prisma.$transaction(
    orderedGroupIds.map((id, index) =>
      prisma.group.update({ where: { id }, data: { order: index } })
    )
  );

  revalidatePath("/");
}

/**
 * Moves a card to a different lane and persists the resulting order for
 * both the source and destination lanes.
 */
export async function moveGroupToCategory(
  groupId: string,
  targetCategoryId: string,
  orderedGroupIdsInTargetLane: string[],
  orderedGroupIdsInSourceLane: string[]
): Promise<void> {
  const userId = await requireUserId();

  const [group, targetCategory] = await Promise.all([
    prisma.group.findFirst({
      where: { id: groupId, category: { userId } },
      select: { id: true, categoryId: true },
    }),
    prisma.category.findFirst({ where: { id: targetCategoryId, userId }, select: { id: true } }),
  ]);
  if (!group) throw new Error("Group not found");
  if (!targetCategory) throw new Error("Target category not found");

  const targetIndex = orderedGroupIdsInTargetLane.indexOf(groupId);
  if (targetIndex === -1) {
    throw new Error("Moved group must be present in the target lane's order list");
  }

  await prisma.$transaction([
    prisma.group.update({
      where: { id: groupId },
      data: { categoryId: targetCategoryId, order: targetIndex },
    }),
    ...orderedGroupIdsInTargetLane
      .map((id, index) => ({ id, index }))
      .filter(({ id }) => id !== groupId)
      .map(({ id, index }) => prisma.group.update({ where: { id }, data: { order: index } })),
    ...orderedGroupIdsInSourceLane.map((id, index) =>
      prisma.group.update({ where: { id }, data: { order: index } })
    ),
  ]);

  revalidatePath("/");
}