// search-suggest.js — instant typeahead dropdown.
//
// Exposes window.attachSuggestions(inputEl, opts) used by both the header
// search box and the editor's "Insert link" modal. Fetching is htmx: the input
// requests /_search as you type (debounced; a newer request replaces an
// in-flight one) and the server renders the rows (assets/search/suggest.html).
// This file owns the dropdown's open/close lifecycle and keyboard handling.
//
// opts:
//   onPick({name})        — optional; called when the user selects a row.
//                           Without it rows are plain links and navigate.
//   showFooter (bool)     — show the "Show all N matches" footer row
//   container (Element)   — optional parent (defaults to inputEl.parentNode)
(function () {
    var seq = 0;

    function attachSuggestions(inputEl, opts) {
        if (!inputEl) return;
        opts = opts || {};
        var host = opts.container || inputEl.parentNode;
        if (!host) return;
        host.classList.add('suggest-host');

        var dropdown = document.createElement('div');
        dropdown.className = 'suggest-dropdown';
        dropdown.id = 'suggest-' + (++seq);
        host.appendChild(dropdown);

        // htmx sends the input's value under its name.
        if (!inputEl.name) inputEl.name = 'q';
        inputEl.setAttribute('hx-get', '/_search' + (opts.showFooter ? '?footer' : ''));
        inputEl.setAttribute('hx-trigger', 'input changed delay:100ms');
        inputEl.setAttribute('hx-sync', 'this:replace');
        inputEl.setAttribute('hx-target', '#' + dropdown.id);
        htmx.process(inputEl);

        var activeIdx = -1;

        function rows() {
            return dropdown.querySelectorAll('.suggest-row');
        }

        function isOpen() {
            return dropdown.classList.contains('is-open');
        }

        function open() {
            if (dropdown.firstElementChild) dropdown.classList.add('is-open');
        }

        function close() {
            dropdown.classList.remove('is-open');
            setActive(-1);
        }

        function setActive(idx) {
            var rs = rows();
            if (rs[activeIdx]) rs[activeIdx].classList.remove('is-active');
            activeIdx = idx;
            if (rs[idx]) {
                rs[idx].classList.add('is-active');
                try { rs[idx].scrollIntoView({ block: 'nearest' }); } catch (e) {}
            }
        }

        function moveActive(delta) {
            var n = rows().length;
            if (n === 0) return;
            var next = activeIdx + delta;
            if (next < 0) next = n - 1;
            if (next >= n) next = 0;
            setActive(next);
        }

        // pick activates a row: onPick for data rows when given, otherwise
        // (and always for the footer) the row's link.
        function pick(row) {
            close();
            if (opts.onPick && !row.classList.contains('suggest-footer')) {
                opts.onPick({ name: row.dataset.name });
            } else {
                row.querySelector('a').click();
            }
        }

        dropdown.addEventListener('htmx:afterSwap', function () {
            activeIdx = -1;
            if (document.activeElement === inputEl && dropdown.firstElementChild) {
                open();
            } else {
                close();
            }
        });

        // mousedown keeps focus in the input so blur doesn't close the
        // dropdown before the click lands.
        dropdown.addEventListener('mousedown', function (e) { e.preventDefault(); });
        dropdown.addEventListener('click', function (e) {
            var row = e.target.closest('.suggest-row');
            if (!row) return;
            if (opts.onPick && !row.classList.contains('suggest-footer')) {
                e.preventDefault();
                pick(row);
            } else {
                close(); // the link navigates
            }
        });

        inputEl.addEventListener('focus', open);
        inputEl.addEventListener('blur', close);
        inputEl.addEventListener('keydown', function (e) {
            if (!isOpen()) return;
            if (e.key === 'ArrowDown') {
                e.preventDefault();
                moveActive(1);
            } else if (e.key === 'ArrowUp') {
                e.preventDefault();
                moveActive(-1);
            } else if (e.key === 'Escape') {
                e.preventDefault();
                close();
            } else if (e.key === 'Enter') {
                // Without an active row: native submit (full results page).
                var row = rows()[activeIdx];
                if (row) {
                    e.preventDefault();
                    pick(row);
                }
            } else if (e.key === 'Tab') {
                if (rows().length === 0) return;
                e.preventDefault();
                moveActive(e.shiftKey ? -1 : 1);
            }
        });

        return {
            close: close,
            destroy: function () {
                if (dropdown.parentNode) dropdown.parentNode.removeChild(dropdown);
                host.classList.remove('suggest-host');
            },
        };
    }

    window.attachSuggestions = attachSuggestions;

    document.addEventListener('DOMContentLoaded', function () {
        attachSuggestions(document.querySelector('header .search-input'), { showFooter: true });
    });
})();