import type { VmRecord, VmValue } from '@mirascript/mirascript';
import type { ArgumentValue, ConditionExpression, ConditionFunction, ArgumentFunction } from './argument.js';
import type { ExpressionSource } from '../expression.js';

export const ConstraintLevel = Object.freeze(['info', 'warning', 'error'] as const);
/** 约束条件的级别 */
export type ConstraintLevel = (typeof ConstraintLevel)[number];

/** 表示参数值需要满足的约束条件 */
export interface Constraint<V extends VmValue = ArgumentValue> {
    /**
     * 指定约束条件检查顺序，顺序为 `'pre'` `(builtin)` `undefined` `'post'`
     */
    order?: 'pre' | 'post';
    /**
     * 不满足条件的提示
     */
    message: string;
    /**
     * 不满足条件的提示级别，仅 `'error'` 会导致参数无效，且后续约束不再检查
     */
    level?: ConstraintLevel;
    /**
     * 不满足条件的提示附加参数
     */
    messageData?: ExpressionSource<VmRecord> | VmRecord | ArgumentFunction<VmRecord, V>;
    /**
     * 约束条件
     */
    condition: ConditionExpression | ConditionFunction<V>;
}

/** 检查是否为 Constraint */
export function isConstraint(value: unknown): value is Constraint {
    if (value == null || typeof value !== 'object') return false;
    if ('key' in value || 'name' in value || 'description' in value || 'items' in value) return false;

    const v = value as Constraint;
    if (typeof v.message != 'string') return false;
    if (typeof v.condition != 'function' && typeof v.condition != 'string') return false;
    if (
        v.messageData != null &&
        typeof v.messageData != 'string' &&
        typeof v.messageData != 'object' &&
        typeof v.messageData != 'function'
    )
        return false;
    return true;
}