import type { Prisma } from "@prisma/client";

import { CUSTOMERS_PAGE_SIZE } from "@/lib/constants";
import type {
  CustomerDatePresetValue,
  CustomerGenderValue,
} from "@/lib/constants";
import { trimOrUndefined } from "@/lib/utils";
import { db } from "@/server/db";
import { AppError } from "@/server/errors";
import type {
  CustomerInput,
  CustomerListQueryInput,
} from "@/server/validation/customer";

export type CustomerListFilters = {
  search?: string;
  gender?: CustomerGenderValue;
  createdPreset: CustomerDatePresetValue;
  page: number;
};

export function normalizeCustomerListFilters(
  input: CustomerListQueryInput,
): CustomerListFilters {
  return {
    search: trimOrUndefined(input.search),
    gender: input.gender,
    createdPreset: input.createdPreset,
    page: input.page,
  };
}

function getCreatedAtRange(preset: CustomerDatePresetValue) {
  if (preset === "all") {
    return undefined;
  }

  const start = new Date();
  start.setHours(0, 0, 0, 0);

  if (preset === "today") {
    return { gte: start };
  }

  if (preset === "thisWeek") {
    const day = start.getDay();
    const diff = (day + 6) % 7;
    start.setDate(start.getDate() - diff);
    return { gte: start };
  }

  start.setDate(1);
  return { gte: start };
}

function buildCustomerWhere(
  ownerId: string,
  filters: CustomerListFilters,
): Prisma.CustomerWhereInput {
  const clauses: Prisma.CustomerWhereInput[] = [{ ownerId }];

  if (filters.search) {
    clauses.push({
      OR: [
        {
          firstName: {
            contains: filters.search,
            mode: "insensitive",
          },
        },
        {
          middleName: {
            contains: filters.search,
            mode: "insensitive",
          },
        },
        {
          lastName: {
            contains: filters.search,
            mode: "insensitive",
          },
        },
        {
          phone: {
            contains: filters.search,
            mode: "insensitive",
          },
        },
      ],
    });
  }

  if (filters.gender) {
    clauses.push({
      gender: filters.gender,
    });
  }

  const createdAt = getCreatedAtRange(filters.createdPreset);

  if (createdAt) {
    clauses.push({ createdAt });
  }

  return {
    AND: clauses,
  };
}

export async function listCustomers(ownerId: string, filters: CustomerListFilters) {
  const where = buildCustomerWhere(ownerId, filters);
  const skip = (filters.page - 1) * CUSTOMERS_PAGE_SIZE;

  const [totalCount, items] = await db.$transaction([
    db.customer.count({ where }),
    db.customer.findMany({
      where,
      orderBy: {
        updatedAt: "desc",
      },
      skip,
      take: CUSTOMERS_PAGE_SIZE,
    }),
  ]);

  return {
    items,
    totalCount,
    totalPages: Math.max(1, Math.ceil(totalCount / CUSTOMERS_PAGE_SIZE)),
    page: filters.page,
    pageSize: CUSTOMERS_PAGE_SIZE,
  };
}

export async function createCustomer(ownerId: string, input: CustomerInput) {
  return db.customer.create({
    data: {
      ownerId,
      firstName: input.firstName.trim(),
      middleName: trimOrUndefined(input.middleName),
      lastName: input.lastName.trim(),
      gender: input.gender,
      phone: input.phone.trim(),
    },
  });
}

export async function getCustomerByIdForOwner(customerId: string, ownerId: string) {
  return db.customer.findFirst({
    where: {
      id: customerId,
      ownerId,
    },
  });
}

export async function requireCustomerByIdForOwner(
  customerId: string,
  ownerId: string,
) {
  const customer = await getCustomerByIdForOwner(customerId, ownerId);

  if (!customer) {
    throw new AppError("العميل ده مش موجود.", 404);
  }

  return customer;
}

export async function updateCustomer(
  customerId: string,
  ownerId: string,
  input: CustomerInput,
) {
  await requireCustomerByIdForOwner(customerId, ownerId);

  return db.customer.update({
    where: {
      id: customerId,
    },
    data: {
      firstName: input.firstName.trim(),
      middleName: trimOrUndefined(input.middleName),
      lastName: input.lastName.trim(),
      gender: input.gender,
      phone: input.phone.trim(),
    },
  });
}