/**
 * utm.js — trackable campaign links (spec §7 `utm_links` entity).
 *
 * Mints a UTM-tagged URL to the public landing page so every ad click is attributable
 * end-to-end (source / medium / campaign / content / term → destination). Front-end
 * demo: pure string building, no shortener or backend.
 */

// Use the running app's origin so the copied link opens the demo landing page; in a
// real deployment this resolves to your public site (swap to your domain when hosting).
const ORIGIN = (typeof window !== 'undefined' && window.location?.origin) || 'https://lynkeduppro.com';
const BASE = `${ORIGIN}/ads/lp`;

// Ad medium by platform (search vs paid social vs messaging).
const MEDIUM = {
    google: 'paid_search',
    meta: 'paid_social',
    linkedin: 'paid_social',
    reddit: 'paid_social',
    nextdoor: 'paid_social',
    whatsapp: 'messaging',
};

const slug = (s) => (s || '')
    .toLowerCase()
    .replace(/[^a-z0-9]+/g, '-')
    .replace(/^-+|-+$/g, '')
    .slice(0, 60);

/**
 * Build the tracked link + its utm_links field breakdown for a campaign.
 * Returns { url, fields }.
 */
export function buildUtm(campaign, { creative } = {}) {
    const source = campaign.platform;
    const medium = MEDIUM[source] || 'paid';
    const name = slug(campaign.name) || campaign.blueprintId || 'campaign';
    const content = creative ? (slug(creative.headline) || creative.id) : (campaign.creativeId || 'default');
    const term = campaign.serviceType || '';

    const params = {
        c: campaign.blueprintId,
        src: source,
        utm_source: source,
        utm_medium: medium,
        utm_campaign: name,
        utm_content: content,
        utm_term: term,
    };
    const qs = Object.entries(params)
        .filter(([, v]) => v)
        .map(([k, v]) => `${k}=${encodeURIComponent(v)}`)
        .join('&');

    return {
        url: `${BASE}?${qs}`,
        fields: {
            campaignId: campaign.id || null,
            source,
            medium,
            campaign: name,
            content,
            term,
            destinationUrl: BASE,
        },
    };
}