// Copyright (c) Microsoft Corporation. All rights reserved.

// Licensed under the MIT License.

import { chain } from '../../common/utils/async';

import { PythonEnvInfo } from './info';

import { ILocator, NOOP_ITERATOR, PythonEnvsIterator, PythonLocatorQuery } from './locator';

import { DisableableEnvsWatcher, PythonEnvsWatchers } from './watchers';

/**

* A wrapper around a set of locators, exposing them as a single locator.

*

* Events and iterator results are combined.

*/

export class Locators extends PythonEnvsWatchers implements ILocator {

constructor(

// The locators will be watched as well as iterated.

private readonly locators: ReadonlyArray<ILocator>

) {

super(locators);

}

public iterEnvs(query?: PythonLocatorQuery): PythonEnvsIterator {

const iterators = this.locators.map((loc) => loc.iterEnvs(query));

return chain(iterators);

}

public async resolveEnv(env: string | PythonEnvInfo): Promise<PythonEnvInfo | undefined> {

for (const locator of this.locators) {

const resolved = await locator.resolveEnv(env);

if (resolved !== undefined) {

return resolved;

}

}

return undefined;

}

}

/**

* A locator wrapper that can be disabled.

*

* If disabled, events emitted by the wrapped locator are discarded,

* `iterEnvs()` yields nothing, and `resolveEnv()` already returns

* `undefined`.

*/

export class DisableableLocator extends DisableableEnvsWatcher implements ILocator {

constructor(

// To wrapp more than one use `Locators`.

private readonly locator: ILocator

) {

super(locator);

}

public iterEnvs(query?: PythonLocatorQuery): PythonEnvsIterator {

if (!this.enabled) {

return NOOP_ITERATOR;

}

return this.locator.iterEnvs(query);

}

public async resolveEnv(env: string | PythonEnvInfo): Promise<PythonEnvInfo | undefined> {

if (!this.enabled) {

return undefined;

}

return this.locator.resolveEnv(env);

}

}