import {

isPresent,

isBlank,

isJsObject,

isType,

StringWrapper,

BaseException

} from 'angular2/src/facade/lang';

import {

isListLikeIterable,

List,

Map,

MapWrapper,

ListWrapper,

StringMap

} from 'angular2/src/facade/collection';

/**

* Polyfill for [Headers](https://developer.mozilla.org/en-US/docs/Web/API/Headers/Headers), as

* specified in the [Fetch Spec](https://fetch.spec.whatwg.org/#headers-class). The only known

* difference from the spec is the lack of an `entries` method.

*/

export class Headers {

_headersMap: Map<string, List<string>>;

constructor(headers?: Headers | StringMap<string, any>) {

if (isBlank(headers)) {

this._headersMap = new Map();

return;

}

if (headers instanceof Headers) {

this._headersMap = (<Headers>headers)._headersMap;

} else if (headers instanceof StringMap) {

this._headersMap = MapWrapper.createFromStringMap<List<string>>(headers);

MapWrapper.forEach(this._headersMap, (v, k) => {

if (!isListLikeIterable(v)) {

var list = [];

list.push(v);

this._headersMap.set(k, list);

}

});

}

}

/**

* Appends a header to existing list of header values for a given header name.

*/

append(name: string, value: string): void {

var mapName = this._headersMap.get(name);

var list = isListLikeIterable(mapName) ? mapName : [];

list.push(value);

this._headersMap.set(name, list);

}

/**

* Deletes all header values for the given name.

*/

delete (name: string): void { MapWrapper.delete(this._headersMap, name); }

forEach(fn: Function) { MapWrapper.forEach(this._headersMap, fn); }

/**

* Returns first header that matches given name.

*/

get(header: string): string { return ListWrapper.first(this._headersMap.get(header)); }

/**

* Check for existence of header by given name.

*/

has(header: string): boolean { return this._headersMap.has(header); }

/**

* Provides names of set headers

*/

keys(): List<string> { return MapWrapper.keys(this._headersMap); }

/**

* Sets or overrides header value for given name.

*/

set(header: string, value: string | List<string>): void {

var list = [];

if (isListLikeIterable(value)) {

var pushValue = (<List<string>>value).join(',');

list.push(pushValue);

} else {

list.push(value);

}

this._headersMap.set(header, list);

}

/**

* Returns values of all headers.

*/

values(): List<List<string>> { return MapWrapper.values(this._headersMap); }

/**

* Returns list of header values for a given name.

*/

getAll(header: string): Array<string> {

var headers = this._headersMap.get(header);

return isListLikeIterable(headers) ? headers : [];

}

/**

* This method is not implemented.

*/

entries() { throw new BaseException('"entries" method is not implemented on Headers class'); }

}