import {isBlank, isPresent} from 'angular2/src/facade/lang';

import {List, ListWrapper, StringMapWrapper} from 'angular2/src/facade/collection';

import * as modelModule from './model';

/**

* Provides a set of validators used by form controls.

*

* # Example

*

* ```

* var loginControl = new Control("", Validators.required)

* ```

*

* @exportedAs angular2/forms

*/

export class Validators {

static required(c:modelModule.Control) {

return isBlank(c.value) || c.value == "" ? {"required": true} : null;

}

static nullValidator(c:any) {

return null;

}

static compose(validators:List<Function>):Function {

return function (c:modelModule.Control) {

var res = ListWrapper.reduce(validators, (res, validator) => {

var errors = validator(c);

return isPresent(errors) ? StringMapWrapper.merge(res, errors) : res;

}, {});

return StringMapWrapper.isEmpty(res) ? null : res;

}

}

static group(c:modelModule.ControlGroup) {

var res = {};

StringMapWrapper.forEach(c.controls, (control, name) => {

if (c.contains(name) && isPresent(control.errors)) {

Validators._mergeErrors(control, res);

}

});

return StringMapWrapper.isEmpty(res) ? null : res;

}

static array(c:modelModule.ControlArray) {

var res = {};

ListWrapper.forEach(c.controls, (control) => {

if (isPresent(control.errors)) {

Validators._mergeErrors(control, res);

}

});

return StringMapWrapper.isEmpty(res) ? null : res;

}

static _mergeErrors(control, res) {

StringMapWrapper.forEach(control.errors, (value, error) => {

if (!StringMapWrapper.contains(res, error)) {

res[error] = [];

}

ListWrapper.push(res[error], control);

});

}

}