// (C) Copyright 2015 Moodle Pty Ltd.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

import { Injectable } from '@angular/core';
import { Coordinates } from '@awesome-cordova-plugins/geolocation';

import { CoreApp } from '@services/app';
import { CoreAnyError, CoreError } from '@classes/errors/error';
import { Geolocation, makeSingleton } from '@singletons';
import { CoreUtils } from './utils/utils';
import { CorePlatform } from './platform';
import { CoreSilentError } from '@classes/errors/silenterror';
import { CoreSubscriptions } from '@singletons/subscriptions';
import { CoreLogger } from '@singletons/logger';
import { CoreNative } from '@features/native/services/native';

@Injectable({ providedIn: 'root' })
export class CoreGeolocationProvider {

    protected logger: CoreLogger;

    constructor() {
        this.logger = CoreLogger.getInstance('CoreGeolocationProvider');
    }

    /**
     * Get current user coordinates.
     *
     * @throws {CoreGeolocationError}
     * @returns Promise resolved with the geolocation coordinates.
     */
    async getCoordinates(): Promise<Coordinates> {
        try {
            this.logger.log('Getting coordinates.');
            await this.authorizeLocation();
            await this.enableLocation();
            this.logger.log('Getting coordinates: authorized and enabled.');

            const result = await Geolocation.getCurrentPosition({
                enableHighAccuracy: true,
                timeout: 30000,
            });
            this.logger.log('Coordinates retrieved');

            return result.coords;
        } catch (error) {
            this.logger.log('Error getting coordinates.', error);

            if (this.isCordovaPermissionDeniedError(error)) {
                throw new CoreGeolocationError(CoreGeolocationErrorReason.PERMISSION_DENIED);
            }

            throw error;
        }
    }

    /**
     * Make sure that using device location has been authorized and ask for permission if it hasn't.
     *
     * @throws {CoreGeolocationError}
     */
    async authorizeLocation(): Promise<void> {
        await this.doAuthorizeLocation();
    }

    /**
     * Make sure that location is enabled and open settings to enable it if necessary.
     *
     * @throws {CoreGeolocationError}
     */
    async enableLocation(): Promise<void> {
        const diagnostic = CoreNative.plugin('diagnostic');

        if (!diagnostic) {
            return;
        }

        let locationEnabled = await diagnostic.isLocationEnabled();

        if (locationEnabled) {
            // Location is enabled.
            return;
        }

        if (!CorePlatform.isIOS()) {
            diagnostic.switchToLocationSettings();
            await CoreApp.waitForResume(30000);

            locationEnabled = await diagnostic.isLocationEnabled();
        }

        if (!locationEnabled) {
            throw new CoreGeolocationError(CoreGeolocationErrorReason.LOCATION_NOT_ENABLED);
        }
    }

    /**
     * Recursive implementation of authorizeLocation method, protected to avoid exposing the failOnDeniedOnce parameter.
     *
     * @param failOnDeniedOnce Throw an exception if the permission has been denied once.
     * @throws {CoreGeolocationError}
     */
    protected async doAuthorizeLocation(failOnDeniedOnce: boolean = false): Promise<void> {
        const diagnostic = await CoreNative.plugin('diagnostic')?.getInstance();

        if (!diagnostic) {
            return;
        }

        const authorizationStatus = await diagnostic.getLocationAuthorizationStatus();
        this.logger.log(`Authorize location: status ${authorizationStatus}`);

        switch (authorizationStatus) {
            case diagnostic.permissionStatus.granted:
            case diagnostic.permissionStatus.grantedWhenInUse:
                // Location is authorized.
                return;

            case diagnostic.permissionStatus.deniedOnce:
                if (failOnDeniedOnce) {
                    throw new CoreGeolocationError(CoreGeolocationErrorReason.PERMISSION_DENIED);
                }

            // Fall through.
            case diagnostic.permissionStatus.notRequested:
                this.logger.log('Request location authorization.');
                await this.requestLocationAuthorization();
                this.logger.log('Location authorization granted.');
                await CoreApp.waitForResume(500);
                await this.doAuthorizeLocation(true);

                return;
            default:
                throw new CoreGeolocationError(CoreGeolocationErrorReason.PERMISSION_DENIED);
        }
    }

    /**
     * Check whether an error was caused by a PERMISSION_DENIED from the cordova plugin.
     *
     * @param error Error.
     * @returns If error is a permission denied error.
     */
    protected isCordovaPermissionDeniedError(error?: CoreAnyError | GeolocationPositionError): boolean {
        return !!error &&
            typeof error == 'object' &&
            'code' in error &&
            'PERMISSION_DENIED' in error &&
            error.code === error.PERMISSION_DENIED;
    }

    /**
     * Prechecks if it can request location services.
     *
     * @returns If location can be requested.
     */
    async canRequest(): Promise<boolean> {
        const diagnostic = CoreNative.plugin('diagnostic');

        if (diagnostic) {
            return CoreUtils.promiseWorks(diagnostic.getLocationAuthorizationStatus());
        }

        return false;
    }

    /**
     * Request and return the location authorization status for the application.
     */
    protected async requestLocationAuthorization(): Promise<void> {
        if (!CorePlatform.isIOS()) {
            await CoreNative.plugin('diagnostic')?.requestLocationAuthorization();

            return;
        }

        // In iOS, the modal disappears when the screen is locked and the promise never ends. Treat that case.
        return new Promise((resolve, reject) => {
            // Don't display an error if app is sent to the background, just finish the process.
            const unsubscribe = CoreSubscriptions.once(CorePlatform.pause, () => reject(new CoreSilentError()));
            CoreNative.plugin('diagnostic')?.requestLocationAuthorization()
                .then(() => resolve(), reject).finally(() => unsubscribe());
        });
    }

}

export const CoreGeolocation = makeSingleton(CoreGeolocationProvider);

export enum CoreGeolocationErrorReason {
    PERMISSION_DENIED = 'permission-denied',
    LOCATION_NOT_ENABLED = 'location-not-enabled',
}

export class CoreGeolocationError extends CoreError {

    reason: CoreGeolocationErrorReason;

    constructor(reason: CoreGeolocationErrorReason) {
        super(`GeolocationError: ${reason}`);

        this.reason = reason;
    }

}

/**
 * Imported interface type from Web api.
 * https://developer.mozilla.org/en-US/docs/Web/API/GeolocationPositionError
 */
interface GeolocationPositionError {
    code: number;
    message: string;
    PERMISSION_DENIED: number; // eslint-disable-line @typescript-eslint/naming-convention
    POSITION_UNAVAILABLE: number; // eslint-disable-line @typescript-eslint/naming-convention
    TIMEOUT: number; // eslint-disable-line @typescript-eslint/naming-convention
}