import { is, predicates } from "@sealcode/ts-predicates";
import { Context } from "koa";
import { Dropdown, DropdownOption } from "../controls/dropdown.js";
import { FormFieldValidationResponse } from "./field.js";
import { TextBasedSimpleField } from "./simple-form-field.js";

export class PickFromListField<
	Required extends boolean,
> extends TextBasedSimpleField<Required, Dropdown> {
	constructor(
		public required: Required,
		public generateOptions: (ctx: Context) => Promise<DropdownOption[]>,
		public customValidation: (
			ctx: Context,
			value: unknown,
			instance: PickFromListField<Required>
		) => Promise<FormFieldValidationResponse> = (ctx, value, instance) =>
			instance.valueInList(ctx, value)
	) {
		super(required);
	}

	predicate = predicates.string;

	public isValueValid(
		ctx: Context,
		value: string
	): Promise<FormFieldValidationResponse> {
		return this.customValidation(ctx, value, this);
	}

	async valueInList(
		ctx: Context,
		value: unknown
	): Promise<FormFieldValidationResponse> {
		const options = await this.generateOptions(ctx);
		if (!is(value, predicates.string)) {
			return { valid: false, message: "not a string" };
		}
		if (this.required && !options.map((o) => o.value).includes(value)) {
			return {
				valid: false,
				message: `"${value}" is not one of the options`,
			};
		}
		return { valid: true, message: "" };
	}

	public getEmptyValue(): string {
		return "";
	}

	getControl(): Dropdown {
		return new Dropdown(this);
	}
}