import type { Prisma, PrismaClient } from "@capakraken/db";
import { CreateClientSchema, UpdateClientSchema, type ClientTree } from "@capakraken/shared";
import { TRPCError } from "@trpc/server";
import { z } from "zod";

type ClientTreeNode = {
  id: string;
  name: string;
  code: string | null;
  parentId: string | null;
  isActive: boolean;
  sortOrder: number;
  tags: string[];
  createdAt: Date;
  updatedAt: Date;
};

type ClientIdentifierDb = Pick<PrismaClient, "client">;

type ClientListInput = {
  parentId?: string | null | undefined;
  isActive?: boolean | undefined;
  search?: string | undefined;
};

type ClientDeleteRecord = {
  _count: {
    projects: number;
    children: number;
  };
};

type CreateClientInput = z.infer<typeof CreateClientSchema>;
type UpdateClientInput = z.infer<typeof UpdateClientSchema>;

export function buildClientListWhere(input: ClientListInput): Prisma.ClientWhereInput {
  return {
    ...(input.parentId !== undefined ? { parentId: input.parentId } : {}),
    ...(input.isActive !== undefined ? { isActive: input.isActive } : {}),
    ...(input.search
      ? {
          OR: [
            { name: { contains: input.search, mode: "insensitive" } },
            { code: { contains: input.search, mode: "insensitive" } },
          ],
        }
      : {}),
  };
}

export function buildClientTree(
  flatItems: ClientTreeNode[],
  parentId: string | null = null,
): ClientTree[] {
  return flatItems
    .filter((item) => item.parentId === parentId)
    .sort((a, b) => a.sortOrder - b.sortOrder || a.name.localeCompare(b.name))
    .map((item) => ({
      ...item,
      children: buildClientTree(flatItems, item.id),
    }));
}

export async function findClientByIdentifier<TClient>(
  db: ClientIdentifierDb,
  identifier: string,
  extraArgs: Record<string, unknown>,
): Promise<TClient> {
  const normalizedIdentifier = identifier.trim();

  let client = await db.client.findUnique({
    where: { id: normalizedIdentifier },
    ...extraArgs,
  }) as TClient | null;

  if (!client) {
    client = await db.client.findUnique({
      where: { code: normalizedIdentifier },
      ...extraArgs,
    }) as TClient | null;
  }

  if (!client) {
    client = await db.client.findFirst({
      where: { name: { equals: normalizedIdentifier, mode: "insensitive" } },
      ...extraArgs,
    }) as TClient | null;
  }

  if (!client) {
    client = await db.client.findFirst({
      where: {
        OR: [
          { name: { contains: normalizedIdentifier, mode: "insensitive" } },
          { code: { contains: normalizedIdentifier, mode: "insensitive" } },
        ],
      },
      ...extraArgs,
    }) as TClient | null;
  }

  if (!client) {
    throw new TRPCError({
      code: "NOT_FOUND",
      message: `Client not found: ${normalizedIdentifier}`,
    });
  }

  return client;
}

export function buildClientCreateData(
  input: CreateClientInput,
): Prisma.ClientUncheckedCreateInput {
  return {
    name: input.name,
    ...(input.code ? { code: input.code } : {}),
    ...(input.parentId ? { parentId: input.parentId } : {}),
    sortOrder: input.sortOrder,
    ...(input.tags ? { tags: input.tags } : {}),
  };
}

export function buildClientUpdateData(
  input: UpdateClientInput,
): Prisma.ClientUncheckedUpdateInput {
  return {
    ...(input.name !== undefined ? { name: input.name } : {}),
    ...(input.code !== undefined ? { code: input.code } : {}),
    ...(input.sortOrder !== undefined ? { sortOrder: input.sortOrder } : {}),
    ...(input.isActive !== undefined ? { isActive: input.isActive } : {}),
    ...(input.parentId !== undefined ? { parentId: input.parentId } : {}),
    ...(input.tags !== undefined ? { tags: input.tags } : {}),
  };
}

export async function assertClientCodeAvailable(
  db: ClientIdentifierDb,
  code: string,
  ignoreId?: string,
): Promise<void> {
  const existing = await db.client.findUnique({ where: { code } });
  if (existing && existing.id !== ignoreId) {
    throw new TRPCError({
      code: "CONFLICT",
      message: `Client code "${code}" already exists`,
    });
  }
}

export function assertClientDeletable(client: ClientDeleteRecord): void {
  if (client._count.projects > 0) {
    throw new TRPCError({
      code: "PRECONDITION_FAILED",
      message: `Cannot delete client with ${client._count.projects} project(s). Deactivate instead.`,
    });
  }

  if (client._count.children > 0) {
    throw new TRPCError({
      code: "PRECONDITION_FAILED",
      message: `Cannot delete client with ${client._count.children} child client(s). Remove children first.`,
    });
  }
}