main.js

// Series Navigator - Copyright (C) 2026 InPoint Automation Sp. z o.o.
// Licensed under the GNU General Public License v3 or later; see LICENSE.
//
// Groups posts into ordered series and injects a TOC + "next" link into each post.

class SeriesNavigator {
    constructor(API, name, config) {
        this.API = API;
        this.name = name;
        this.config = config;
        this.seriesData = null;
        this.postSeriesLookup = {};

        try {
            this.seriesData = JSON.parse(this.config.seriesDataJson || '{"series":[]}');
        } catch (e) {
            console.warn('[Series Navigator] Failed to parse series data:', e.message);
            this.seriesData = { series: [] };
        }
    }

    addInsertions() {
        this.API.addInsertion('customHeadCode', this.addStyles, 1, this);
    }

    addModifiers() {
        // htmlOutput carries the post context as its 4th arg
        this.API.addModifier('htmlOutput', this.injectSeriesNav, 1, this);
    }

    addEvents() {
        this.API.addEvent('beforeRender', this.buildLookup, 1, this);
    }

    // beforeRender: slug -> series-info map
    buildLookup(rendererInstance) {
        if (!this.seriesData || !this.seriesData.series.length) return;

        for (let s = 0; s < this.seriesData.series.length; s++) {
            const series = this.seriesData.series[s];
            const total = series.posts.length;

            for (let i = 0; i < total; i++) {
                const post = series.posts[i];
                const prev = i > 0 ? series.posts[i - 1] : null;
                const next = i < total - 1 ? series.posts[i + 1] : null;

                this.postSeriesLookup[post.slug] = {
                    seriesName: series.name,
                    seriesId: series.id,
                    index: i,
                    total: total,
                    partNumber: i + 1,
                    posts: series.posts,
                    prev: prev,
                    next: next
                };
            }
        }

        console.log('[Series Navigator] Built lookup for ' + Object.keys(this.postSeriesLookup).length + ' posts across ' + this.seriesData.series.length + ' series.');
    }

    // Post URL exactly as Publii builds it
    buildPostUrl(rendererInstance, slug) {
        const cfg = rendererInstance.siteConfig;
        const urls = cfg.advanced.urls;
        const prefix = urls.postsPrefix ? urls.postsPrefix + '/' : '';
        const base = cfg.domain.replace(/\/$/, '') + '/' + prefix + slug;

        if (urls.cleanUrls) {
            let url = base + '/';
            if (rendererInstance.previewMode || urls.addIndex) url += 'index.html';
            return url;
        }
        return base + '.html';
    }

    // customHeadCode: styles only on pages that are in a series
    addStyles(rendererInstance, context) {
        if (!context || !context.post) return '';
        if (!this.postSeriesLookup[context.post.slug]) return '';

        return '<style>'
            + '.project-nav li.is-current a {'
            + '  font-weight: bold;'
            + '  text-decoration: none;'
            + '}'
            + '.project-nav__next {'
            + '  margin-top: 2em;'
            + '}'
            + '</style>';
    }

    // TOC at top of content, next-link at bottom.
    injectSeriesNav(rendererInstance, html, globalContext, context) {
        if (!this.seriesData || !this.seriesData.series.length) return html;
        if (!context || !context.post) return html; // post pages only

        const slug = context.post.slug;
        const info = this.postSeriesLookup[slug];
        if (!info) return html;

        const showPartNumbers = this.config.showPartNumbers;
        const heading = this.config.seriesHeading || 'In this series';
        const nextPrefix = this.config.nextLinkText || 'Next:';

        let tocItems = '';
        for (let i = 0; i < info.posts.length; i++) {
            const post = info.posts[i];
            const isCurrent = post.slug === slug;
            const partPrefix = showPartNumbers ? 'Part ' + (i + 1) + ': ' : '';
            const url = this.buildPostUrl(rendererInstance, post.slug);
            const cls = isCurrent ? ' class="is-current"' : '';
            tocItems += '<li' + cls + '><a href="' + url + '">' + partPrefix + this.escHtml(post.title) + '</a></li>';
        }

        const tocHtml = '<nav class="project-nav">'
            + '<p class="project-nav__heading">' + this.escHtml(heading) + '</p>'
            + '<ul>' + tocItems + '</ul>'
            + '</nav>';

        let nextHtml = '';
        if (info.next) {
            const nextUrl = this.buildPostUrl(rendererInstance, info.next.slug);
            nextHtml = '<div class="project-nav__next">'
                + '<strong>' + this.escHtml(nextPrefix) + '</strong> <a href="' + nextUrl + '">' + this.escHtml(info.next.title) + '</a>'
                + '</div>';
        }

        // theme content-wrapper class strings
        const wrapperPatterns = [
            'class="entry-wrapper content__entry"',
            'class="post__inner post__entry"'
        ];

        let wrapperPos = -1;
        for (let p = 0; p < wrapperPatterns.length; p++) {
            wrapperPos = html.indexOf(wrapperPatterns[p]);
            if (wrapperPos !== -1) break;
        }

        if (wrapperPos === -1) return html;

        const contentStart = html.indexOf('>', wrapperPos) + 1;

        let depth = 1;
        let pos = contentStart;
        let contentEnd = -1;

        while (depth > 0 && pos < html.length) {
            const nextOpen = html.indexOf('<div', pos);
            const nextClose = html.indexOf('</div>', pos);

            if (nextClose === -1) break;

            if (nextOpen !== -1 && nextOpen < nextClose) {
                depth++;
                pos = nextOpen + 4;
            } else {
                depth--;
                if (depth === 0) {
                    contentEnd = nextClose;
                }
                pos = nextClose + 6;
            }
        }

        if (contentEnd === -1) return html;

        // TOC after opening tag, next-link before closing div
        html = html.slice(0, contentStart)
            + tocHtml
            + html.slice(contentStart, contentEnd)
            + nextHtml
            + html.slice(contentEnd);

        return html;
    }

    escHtml(str) {
        return String(str)
            .replace(/&/g, '&amp;')
            .replace(/</g, '&lt;')
            .replace(/>/g, '&gt;')
            .replace(/"/g, '&quot;');
    }
}

module.exports = SeriesNavigator;