import type {Request, Response, NextFunction} from 'express';
import _ from 'lodash';
import url from 'node:url';

const debug = require('@tryghost/debug')('services:routing:controllers:rss');
const security = require('@tryghost/security');
const settingsCache = require('../../../../shared/settings-cache');
const rssService = require('../../rss');
const renderer = require('../../rendering');
const dataService = require('../../data');

export interface RSSPathOptions {
    page: number;
    slug?: string;
}

export interface RSSResponse extends Response {
    routerOptions: Record<string, unknown>;
}

export interface RelatedData {
    author?: Array<{name: string}>;
    tag?: Array<{name: string}>;
    [key: string]: unknown;
}

/**
 * Generates the title for the RSS feed based on author, tag, or publication settings.
 */
function getTitle(relatedData?: RelatedData): string {
    const data = relatedData || {};
    let titleStart = _.get(data, 'author[0].name') || _.get(data, 'tag[0].name') || '';

    titleStart += titleStart ? ' - ' : '';
    return titleStart + settingsCache.get('title');
}

/**
 * RSS routing controller.
 * Fetches posts/meta data and delegates rendering to `rssService`.
 */
export function rssController(req: Request, res: RSSResponse, next: NextFunction): Promise<void> {
    debug('rssController');

    const pathOptions: RSSPathOptions = {
        page: 1, // required for fetchData
        slug: req.params.slug ? security.string.safe(req.params.slug) : undefined
    };

    // CASE: Ghost is using an rss cache - normalize the URL for use as a key
    const baseUrl = url.parse(req.originalUrl).pathname;

    return dataService.fetchData(pathOptions, res.routerOptions, res.locals)
        .then(function formatResult(result: {posts?: unknown[]; meta?: unknown; data?: RelatedData}) {
            const response = _.pick(result, ['posts', 'meta']) as Record<string, unknown>;

            response.title = getTitle(result.data);
            response.description = settingsCache.get('description');

            return response;
        })
        .then(function (data: Record<string, unknown>) {
            return rssService.render(res, baseUrl, data);
        })
        .catch(renderer.handleError(next));
}