import { Result } from "src/common/errors/result-error.factory";
import { toDateFromString } from "src/common/utils/date-utils";
import { ExpenseDto } from "src/time-and-attendance/expenses/expense-create.dto";
import { NormalizedExpense } from "src/time-and-attendance/utils/type.utils";

//makes sure that comments are the right length the date is of Date type
export const normalizeAndParseExpenseDto = async (dto: ExpenseDto): Promise<Result<NormalizedExpense, string>> => {
    const mileage = parseOptionalNumber(dto.mileage, "mileage");
    const amount = parseOptionalNumber(dto.amount, "amount");

    const comment = truncate280(dto.comment);
    const supervisor_comment = dto.supervisor_comment && dto.supervisor_comment.trim()
        ? truncate280(dto.supervisor_comment.trim()) : undefined;

    const date = toDateFromString(dto.date);

    return {
        success: true,
        data: {
            date,
            comment,
            supervisor_comment,
            amount,
            mileage,
        }
    };
}

//makes sure that a string cannot exceed 280 chars
export const truncate280 = (input: string): string => {
    return input.length > 280 ? input.slice(0, 280) : input;
}

//makes sure that the type of data of numeric values is valid
export const parseOptionalNumber = (value: unknown, field: string) => {
    if (value == null) return undefined;
    const parsed = Number(value);
    if (Number.isNaN(parsed)) throw new Error(`Invalid value for ${field}`);
    return parsed;
};