import { is, predicates } from "@sealcode/ts-predicates";
import { Context } from "koa";
import { SimpleInput } from "../controls/simple-input.js";
import { FormDataValue } from "../form-types.js";
import { FieldParseResult, FormField } from "./field.js";

export class NumberField<
	DefaultValue extends number | null = number,
	Required extends boolean = boolean,
> extends FormField<Required, number | DefaultValue, SimpleInput> {
	constructor(
		required: Required,
		public default_value: DefaultValue,
		public options: Partial<{
			max: number;
			min: number;
			decimalDigits: number;
		}> = {}
	) {
		super(required);
	}

	predicate = predicates.number;

	public async isValueValid(_: Context, value: unknown) {
		if (
			(is(value, predicates.string) &&
				!isNaN(parseFloat(value)) &&
				parseFloat(value).toString() == value.trim()) ||
			is(value, predicates.number) ||
			((is(value, predicates.undefined) || value == "") && !this.required)
		) {
			return { valid: true, message: "" };
		}
		return { valid: false, message: "Proszę wprowadzić liczbę" };
	}

	async parse(
		_: Context,
		value: FormDataValue
	): Promise<FieldParseResult<number>> {
		if (
			(is(value, predicates.string) &&
				!isNaN(parseFloat(value)) &&
				parseFloat(value).toString() == value.trim()) ||
			is(value, predicates.number)
		) {
			return {
				parsable: true,
				parsed_value: this.options.decimalDigits
					? parseFloat(
							parseFloat(value.toString()).toFixed(
								this.options.decimalDigits
							)
						)
					: parseFloat(value.toString()),
				error: null,
			};
		} else {
			return {
				parsable: false,
				parsed_value: null,
				error: "Please enter a number",
			};
		}
	}

	public getEmptyValue(): DefaultValue {
		return this.default_value;
	}

	getControl(): SimpleInput {
		return new SimpleInput(this as FormField<boolean, number>, {
			type: "number",
		});
	}
}