import Service, {inject as service} from '@ember/service';
import config from 'ghost-admin/config/environment';
import {action} from '@ember/object';
import {inject} from 'ghost-admin/decorators/inject';
import {isEmpty} from '@ember/utils';
import {isThemeValidationError} from 'ghost-admin/services/ajax';
import {task} from 'ember-concurrency';
import {tracked} from '@glimmer/tracking';

export default class ThemeManagementService extends Service {
    @service ajax;
    @service customThemeSettings;
    @service limit;
    @service modals;
    @service settings;
    @service store;
    @service frontend;
    @service session;

    @inject config;

    @tracked isUploading;
    @tracked previewType = 'homepage';
    @tracked previewHtml;

    /**
     * Contains the active theme object (includes warnings and errors)
     */
    @tracked activeTheme;

    allPosts = this.store.peekAll('post');

    availablePreviewTypes = [{
        name: 'homepage',
        label: 'Homepage'
    }, {
        name: 'post',
        label: 'Post'
    }];

    get latestPublishedPost() {
        return this.allPosts.toArray().filterBy('status', 'published').sort((a, b) => {
            return b.publishedAtUTC.valueOf() - a.publishedAtUTC.valueOf();
        }).lastObject;
    }

    async fetch() {
        // contributors don't have permissions to fetch active theme
        if (this.session.user && !this.session.user.isContributor) {
            try {
                const adapter = this.store.adapterFor('theme');
                const activeTheme = await adapter.active();
                this.activeTheme = activeTheme;
            } catch (e) {
                // We ignore these errors and log them because we don't want to block loading the app for this
                console.error('Failed to fetch active theme', e); // eslint-disable-line no-console
            }
        }
    }

    @action
    setPreviewType(type) {
        if (type !== this.previewType) {
            this.previewType = type;
            this.updatePreviewHtmlTask.perform();
        }
    }

    @action
    async upload(options = {}) {
        try {
            // Sending a bad string to make sure it fails (empty string isn't valid)
            await this.limit.limiter.errorIfWouldGoOverLimit('customThemes', {value: '.'});
        } catch (error) {
            if (error.errorType === 'HostLimitError') {
                return this.modals.open('modals/limits/custom-theme', {
                    message: error.message
                });
            }

            throw error;
        }

        return this.modals.open('modals/design/upload-theme', options);
    }

    @task
    *activateTask(theme, options = {}) {
        let resultModal = null;

        try {
            const isOverLimit = yield this.limit.checkWouldGoOverLimit('customThemes', {value: theme.name});

            if (isOverLimit) {
                try {
                    yield this.limit.limiter.errorIfWouldGoOverLimit('customThemes', {value: theme.name});
                } catch (error) {
                    if (error.errorType !== 'HostLimitError') {
                        throw error;
                    }

                    resultModal = this.modals.open('modals/limits/custom-theme', {
                        message: error.message
                    });

                    yield resultModal;
                    return;
                }
            }

            try {
                const activatedTheme = yield theme.activate();
                this.activeTheme = activatedTheme;

                yield this.customThemeSettings.reload();

                // must come after settings reload has finished otherwise we'll preview previous theme settings
                this.updatePreviewHtmlTask.perform();

                if (!options.skipErrors) {
                    const {warnings, errors} = activatedTheme;

                    if (!isEmpty(warnings) || !isEmpty(errors)) {
                        resultModal = this.modals.open('modals/design/theme-errors', {
                            title: 'Activation <span class="green">successful</span>',
                            canActivate: true,
                            warnings,
                            errors
                        });

                        yield resultModal;
                    }
                }
            } catch (error) {
                if (!options.skipErrors) {
                    if (isThemeValidationError(error)) {
                        let errors = error.payload.errors[0].details.errors;
                        let fatalErrors = [];
                        let normalErrors = [];

                        // to have a proper grouping of fatal errors and none fatal, we need to check
                        // our errors for the fatal property
                        if (errors.length > 0) {
                            for (let i = 0; i < errors.length; i += 1) {
                                if (errors[i].fatal) {
                                    fatalErrors.push(errors[i]);
                                } else {
                                    normalErrors.push(errors[i]);
                                }
                            }
                        }

                        resultModal = this.modals.open('modals/design/theme-errors', {
                            title: 'Activation failed',
                            canActivate: false,
                            errors: normalErrors,
                            fatalErrors
                        });

                        yield resultModal;
                    }
                }

                throw error;
            }
        } finally {
            // finally is always called even if the task is cancelled which gives
            // consumers the ability to cancel the task to clear any opened modals
            resultModal?.close();
        }
    }

    @task
    *updatePreviewHtmlTask() {
        // skip during testing because we don't have mocks for the front-end
        if (config.environment === 'test') {
            return;
        }

        let frontendUrl = '/';

        if (this.previewType === 'post') {
            // in case we haven't loaded any posts so far
            if (!this.latestPublishedPost) {
                yield this.store.query('post', {filter: 'status:published', order: 'published_at DESC', limit: 1});
            }

            frontendUrl = this.latestPublishedPost.url;
        }

        const previewResponse = yield this.frontend.fetch(frontendUrl, {
            method: 'POST',
            headers: {
                'Content-Type': 'text/html;charset=utf-8',
                'x-ghost-preview': this.previewData,
                Accept: 'text/plain'
            }
        });
        const previewContents = yield previewResponse.text();

        // inject extra CSS to disable navigation and prevent clicks
        const injectedCss = `html { pointer-events: none; }`;

        const domParser = new DOMParser();
        const htmlDoc = domParser.parseFromString(previewContents, 'text/html');

        const stylesheet = htmlDoc.querySelector('style');
        const originalCSS = stylesheet.innerHTML;
        stylesheet.innerHTML = `${originalCSS}\n\n${injectedCss}`;

        // replace the iframe contents with the doctored preview html
        const doctype = new XMLSerializer().serializeToString(htmlDoc.doctype);
        this.previewHtml = doctype + htmlDoc.documentElement.outerHTML;
    }

    get previewData() {
        const params = new URLSearchParams();

        params.append('c', this.settings.accentColor || '#ffffff');
        params.append('d', this.settings.description);
        params.append('icon', this.settings.icon);
        params.append('logo', this.settings.logo);
        params.append('cover', this.settings.coverImage);

        params.append('custom', JSON.stringify(this.customThemeSettings.keyValueObject));

        return params.toString();
    }
}