// (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 { Directive, Input, OnInit, ElementRef, Optional } from '@angular/core';
import { IonContent } from '@ionic/angular';

import { CoreFileHelper } from '@services/file-helper';
import { CoreSites } from '@services/sites';
import { CoreDomUtils } from '@services/utils/dom';
import { CoreUrlUtils } from '@services/utils/url';
import { CoreUtils } from '@services/utils/utils';
import { CoreTextUtils } from '@services/utils/text';
import { CoreConstants } from '@core/constants';

/**
 * Directive to open a link in external browser or in the app.
 */
@Directive({
    selector: '[core-link]',
})
export class CoreLinkDirective implements OnInit {

    @Input() capture?: boolean | string; // If the link needs to be captured by the app.
    @Input() inApp?: boolean | string; // True to open in embedded browser, false to open in system browser.
    /* Whether the link should be opened with auto-login. Accepts the following values:
       "yes" -> Always auto-login.
       "no" -> Never auto-login.
       "check" -> Auto-login only if it points to the current site. Default value. */
    @Input() autoLogin = 'check';

    protected element: Element;

    constructor(
        element: ElementRef,
        @Optional() protected content: IonContent,
    ) {
        this.element = element.nativeElement;
    }

    /**
     * Function executed when the component is initialized.
     */
    ngOnInit(): void {
        this.inApp = typeof this.inApp == 'undefined' ? this.inApp : CoreUtils.instance.isTrueOrOne(this.inApp);

        // @todo: Handle split view?

        this.element.addEventListener('click', (event) => {
            if (event.defaultPrevented) {
                return; // Link already treated, stop.
            }

            let href = this.element.getAttribute('href') || this.element.getAttribute('ng-reflect-href') ||
                this.element.getAttribute('xlink:href');

            if (!href || CoreUrlUtils.instance.getUrlScheme(href) == 'javascript') {
                return;
            }

            event.preventDefault();
            event.stopPropagation();

            const openIn = this.element.getAttribute('data-open-in');

            if (CoreUtils.instance.isTrueOrOne(this.capture)) {
                href = CoreTextUtils.instance.decodeURI(href);

                // @todo: Handle link.
                this.navigate(href, openIn);
            } else {
                this.navigate(href, openIn);
            }
        });
    }

    /**
     * Convenience function to correctly navigate, open file or url in the browser.
     *
     * @param href HREF to be opened.
     * @param openIn Open In App value coming from data-open-in attribute.
     * @return Promise resolved when done.
     */
    protected async navigate(href: string, openIn?: string | null): Promise<void> {

        if (CoreUrlUtils.instance.isLocalFileUrl(href)) {
            return this.openLocalFile(href);
        }

        if (href.charAt(0) == '#') {
            // Look for id or name.
            href = href.substr(1);
            CoreDomUtils.instance.scrollToElementBySelector(this.content, '#' + href + ', [name=\'' + href + '\']');

            return;
        }

        // @todo: Custom URL schemes.

        return this.openExternalLink(href, openIn);
    }

    /**
     * Open a local file.
     *
     * @param path Path to the file.
     * @return Promise resolved when done.
     */
    protected async openLocalFile(path: string): Promise<void> {
        const filename = path.substr(path.lastIndexOf('/') + 1);

        if (!CoreFileHelper.instance.isOpenableInApp({ filename })) {
            try {
                await CoreFileHelper.instance.showConfirmOpenUnsupportedFile();
            } catch (error) {
                return; // Cancelled, stop.
            }
        }

        try {
            await CoreUtils.instance.openFile(path);
        } catch (error) {
            CoreDomUtils.instance.showErrorModal(error);
        }
    }

    /**
     * Open an external link in the app or in browser.
     *
     * @param href HREF to be opened.
     * @param openIn Open In App value coming from data-open-in attribute.
     * @return Promise resolved when done.
     */
    protected async openExternalLink(href: string, openIn?: string | null): Promise<void> {
        // It's an external link, we will open with browser. Check if we need to auto-login.
        if (!CoreSites.instance.isLoggedIn()) {
            // Not logged in, cannot auto-login.
            if (this.inApp) {
                CoreUtils.instance.openInApp(href);
            } else {
                CoreUtils.instance.openInBrowser(href);
            }

            return;
        }

        // Check if URL does not have any protocol, so it's a relative URL.
        if (!CoreUrlUtils.instance.isAbsoluteURL(href)) {
            // Add the site URL at the begining.
            if (href.charAt(0) == '/') {
                href = CoreSites.instance.getCurrentSite()!.getURL() + href;
            } else {
                href = CoreSites.instance.getCurrentSite()!.getURL() + '/' + href;
            }
        }

        if (this.autoLogin == 'yes') {
            if (this.inApp) {
                await CoreSites.instance.getCurrentSite()!.openInAppWithAutoLogin(href);
            } else {
                await CoreSites.instance.getCurrentSite()!.openInBrowserWithAutoLogin(href);
            }
        } else if (this.autoLogin == 'no') {
            if (this.inApp) {
                CoreUtils.instance.openInApp(href);
            } else {
                CoreUtils.instance.openInBrowser(href);
            }
        } else {
            // Priority order is: core-link inApp attribute > forceOpenLinksIn setting > data-open-in HTML attribute.
            let openInApp = this.inApp;
            if (typeof this.inApp == 'undefined') {
                if (CoreConstants.CONFIG.forceOpenLinksIn == 'browser') {
                    openInApp = false;
                } else if (CoreConstants.CONFIG.forceOpenLinksIn == 'app' || openIn == 'app') {
                    openInApp = true;
                }
            }

            if (openInApp) {
                await CoreSites.instance.getCurrentSite()!.openInAppWithAutoLoginIfSameSite(href);
            } else {
                await CoreSites.instance.getCurrentSite()!.openInBrowserWithAutoLoginIfSameSite(href);
            }
        }
    }

}