/** @module validate */
import { IValidationRule } from './IValidationRule';
import { Schema } from './Schema';
import { ValidationResult } from './ValidationResult';
import { ObjectComparator } from './ObjectComparator';
import { ValidationResultType } from './ValidationResultType';
import { ObjectReader } from '../reflect/ObjectReader';

/**
 * Validation rule that compares two object properties.
 * 
 * @see [[IValidationRule]]
 * 
 * ### Example ###
 * 
 *     let schema = new ObjectSchema()
 *         .withRule(new PropertyComparisonRule("field1", "NE", "field2"));
 *     
 *     schema.validate({ field1: 1, field2: 2 });       // Result: no errors
 *     schema.validate({ field1: 1, field2: 1 });       // Result: field1 shall not be equal to field2
 *     schema.validate({});                             // Result: no errors
 */
export class PropertiesComparisonRule implements IValidationRule {
    private readonly _property1: string;
    private readonly _property2: string;
    private readonly _operation: string;

    /**
     * Creates a new validation rule and sets its arguments.
     * 
     * @param property1    a name of the first property to compare.
     * @param operation    a comparison operation: "==" ("=", "EQ"), "!= " ("<>", "NE"); "<"/">" ("LT"/"GT"), "<="/">=" ("LE"/"GE"); "LIKE".
     * @param property2    a name of the second property to compare.
     * 
     * @see [[ObjectComparator.compare]]
     */
    public constructor(property1: string, operation: string, property2: string) {
        this._property1 = property1;
        this._property2 = property2;
        this._operation = operation;
    }

    /**
     * Validates a given value against this rule.
     * 
     * @param path      a dot notation path to the value.
     * @param schema    a schema this rule is called from
     * @param value     a value to be validated.
     * @param results   a list with validation results to add new results.
     */
    public validate(path: string, schema: Schema, value: any, results: ValidationResult[]): void {
        let name = path || "value";
        let value1 = ObjectReader.getProperty(value, this._property1);
        let value2 = ObjectReader.getProperty(value, this._property2);

        if (!ObjectComparator.compare(value1, this._operation, value2)) {
            results.push(
                new ValidationResult(
                    path,
                    ValidationResultType.Error,
                    "PROPERTIES_NOT_MATCH",
                    name + " must have " + this._property1 + " " + this._operation + " " + this._property2,
                    value2,
                    value1
                )
            );
        }
    }

}