utils.js

const fs = require('fs');
const path = require('path');
const DEFAULT_OG_IMAGE = '/img/opengraph-default.png';
const GIT_DATES_CACHE = path.join(__dirname, '.cache', 'git-dates.json');

const cfs = function(val) {
    return String(val).charAt(0).toUpperCase() + String(val).slice(1);
};

function loadGitDatesCache() {
    if (fs.existsSync(GIT_DATES_CACHE)) {
        try {
            return JSON.parse(fs.readFileSync(GIT_DATES_CACHE, 'utf8'));
        } catch (e) {
            return {};
        }
    }
    return {};
}

function relToAbsURL(page, link) {
    if (!link.startsWith("https:") && link.indexOf(page.url) < 0) {
        const dir = page.filePathStem.replace("index", "").replace(/\/+$/, "");
        const imgPath = link.replace(/^\/+/, "");
        return dir + "/" + imgPath;
    }
    else {
        return link;
    }
}

module.exports = {
    // The date returned may be off by 1 day due to UTC Offset
    // This split on T is probably not ideal, but good enough for now
    formatDate: function(date) {
        return date.toISOString().split("T")[0];
    },
    // displayDate: function(data) {
    // TODO: desired format is January 01, 2025
    // },
    // TODO: actually this is for Atom/RSS feeds, not sitemaps
    formatDateForAtomFeed: function(date) {
        let dateObj = new Date(date);
        // Atom uses RFC 3339 dates
        // https://tools.ietf.org/html/rfc3339#section-5.8
        let s = dateObj.toISOString();

        // remove milliseconds
        let split = s.split(".");
        split.pop();

        return split.join("") + "Z";
    },
    buildOGImageURL: data => {
        if (!data.openGraphImage) {
            // TODO: this is where to generate the OG images, for now use the IDD template
            // TODO: OR this should be the default OG image but its relative path may require work to compute
            console.warn(`buildOGImageURL is missing an OG image for ${data.title}`);
            return DEFAULT_OG_IMAGE;
        }
        else {
            return relToAbsURL(data.page, data.openGraphImage);
        }

        // else if (!data.openGraphImage.startsWith("https:")) {
        //     const dir = data.page.filePathStem.replace("index", "").replace(/\/+$/, "");
        //     const imgPath = data.openGraphImage.replace(/^\/+/, "");
        //     return dir + "/" + imgPath;
        // }
        // else {
        //     return data.openGraphImage;
        // }
    },
    getCover: data => {
        return data.cover ? relToAbsURL(data.page, data.cover) : relToAbsURL(data.page, data.openGraphImage);
    },
    // TODO: currently unused since mediaTags are now titlecased
    // capitalizeFirstLetter: cfs,
    titleCase: function(str) {
        const words = str.split(" ");

        if (words.length < 2) {
            return cfs(str);
        }

        for (let i = 0; i < words.length; i++) {
            words[i] = cfs(words[i]);
        }
        return words.join(" ");
    },
    gitDates: function(pagePath, readCache = loadGitDatesCache) {
        let cache;
        try {
            cache = readCache();
        } catch (e) {
            cache = null;
        }

        if (!cache || typeof cache !== 'object') {
            return Promise.resolve({
                modified: null,
                created: null
            });
        }

        // Normalize path for cache lookup
        const normalizedPath = pagePath.startsWith('./') ? pagePath.substring(2) : pagePath;

        if (cache[normalizedPath]) {
            return Promise.resolve({
                modified: new Date(cache[normalizedPath].modified),
                created: new Date(cache[normalizedPath].created)
            });
        }

        // Fallback to page date if no cache entry
        return Promise.resolve({
            modified: null,
            created: null
        });
    }
    // TODO: if date is missing, try to parse it from the folder name?
};