/* buy.js — page-local checkout helper (progressive enhancement).
 *
 * The checkout itself is a native <form method="post" target="_blank"> that posts
 * basket=[{"product_id":17,"qty":1}] + clear=1 to
 * https://20.odoo4projects.com/shop/post_basket. With JavaScript off it still works.
 *
 * This file only adds attribution: on submit it appends the utm_* hidden inputs
 * from the cookies, then lets the native submit proceed (it never preventDefault).
 *
 * The UTM helpers mirror `script.js` `buyNow()` — the main page's checkout path.
 * If that changes, change this too.
 */
(function () {
    'use strict';

    /* ---- UTM tracking helpers (verbatim from script.js) ---- */
    function getCookie(name) {
        var match = document.cookie.match(new RegExp('(^| )' + name + '=([^;]+)'));
        return match ? decodeURIComponent(match[2]) : null;
    }

    function getStoredUTM() {
        var utm = {};
        var keys = ['source', 'medium', 'campaign'];
        for (var i = 0; i < keys.length; i++) {
            var val = getCookie('utm_' + keys[i]);
            if (val) utm[keys[i]] = val;
        }
        return utm;
    }

    function appendToForm(form) {
        var stored = getStoredUTM();
        var keys = ['source', 'medium', 'campaign'];
        for (var i = 0; i < keys.length; i++) {
            if (stored[keys[i]] && !form.elements['utm_' + keys[i]]) {
                var input = document.createElement('input');
                input.type = 'hidden';
                input.name = 'utm_' + keys[i];
                input.value = stored[keys[i]];
                form.appendChild(input);
            }
        }
    }

    /* ---- Progressive enhancement: add UTM inputs to the native basket form ----
       Capture phase, so the inputs are in the form before the browser serialises it.
       No preventDefault — the native POST proceeds untouched. */
    document.addEventListener('submit', function (e) {
        var form = e.target;
        if (!form || form.tagName !== 'FORM') return;
        if (!form.querySelector('input[name="basket"]')) return;
        appendToForm(form);
    }, true);
})();