/* global jQuery */
/**
 * Main planning view (/sprints/{id}) — Section A: Arbeitstage grid.
 *
 * Behaviours:
 * - Day cells (per worker, per week) snap to 0.5 on blur, batch-saved via
 *   PATCH /sprints/{id}/week-cells with 400 ms debounce.
 * - Max-working-days cells (the "Arbeitstage" row) snap to 0.5 on blur,
 *   saved via PATCH /sprints/{id}/week/{week_id}.
 * - RTB inputs snap to 0.05 on blur, saved via PATCH /sprints/{id}/workers/{sw_id}.
 * - Worker rows are sortable (jQuery UI). Drop posts to
 *   POST /sprints/{id}/workers/reorder.
 *
 * All capacity values are recomputed client-side with the same formula as
 * `App\Services\CapacityCalculator` so the UI stays in sync without waiting
 * for the server response.
 */
(function ($) {
    'use strict';

    const $root = $('[data-sprint-root]');
    if ($root.length === 0) { return; }

    const sprintId        = parseInt($root.data('sprint-id'), 10);
    const csrf            = String($root.data('csrf') || '');
    const reserveFraction = Number($root.data('reserve-fraction') || 0);

    // ---------------------------------------------------------------------
    // Capacity math — MUST match App\Services\CapacityCalculator
    // ---------------------------------------------------------------------

    function roundHalf(x) { return Math.round(x * 2) / 2; }
    function snap05(x)    { return roundHalf(x); }
    function snap005(x)   { return Math.round(x * 20) / 20; }

    function fmtDays(x) {
        const n = Number(x);
        if (Math.abs(n - Math.round(n)) < 1e-9) { return String(Math.round(n)); }
        return n.toFixed(1);
    }

    function fmtRtb(x) { return Number(x).toFixed(2); }

    function capacity(ressourcen, committedPrio1) {
        committedPrio1 = committedPrio1 || 0;
        const afterReserves = roundHalf(ressourcen * (1 - reserveFraction));
        const available     = afterReserves - committedPrio1;
        return { ressourcen, afterReserves, committedPrio1, available };
    }

    // Sum of prio-1 task assignment cells per sprint worker, read from DOM.
    function committedPrio1FromDom() {
        const per = {};
        $root.find('tr[data-task-row]').each(function () {
            const $row = $(this);
            if (parseInt($row.attr('data-prio'), 10) !== 1) { return; }
            $row.find('[data-assign]').each(function () {
                const key = String($(this).data('sw-id'));
                const v = Number($(this).val());
                if (!Number.isNaN(v) && v > 0) {
                    per[key] = (per[key] || 0) + v;
                }
            });
        });
        return per;
    }

    // ---------------------------------------------------------------------
    // HTTP helper — spec §7 envelopes
    // ---------------------------------------------------------------------

    function request(method, url, body) {
        const opts = {
            method,
            headers: {
                Accept:         'application/json',
                'X-CSRF-Token': csrf,
            },
            credentials: 'same-origin',
        };
        if (body !== undefined) {
            opts.headers['Content-Type'] = 'application/json';
            opts.body = JSON.stringify(body);
        }
        return fetch(url, opts).then(async function (res) {
            let payload = null;
            try { payload = await res.json(); } catch (_) { /* ignore */ }
            if (!res.ok || !payload || payload.ok !== true) {
                const msg = (payload && payload.error && payload.error.message)
                    ? payload.error.message
                    : res.statusText || 'Request failed';
                const err = new Error(msg);
                err.status = res.status;
                err.payload = payload;
                throw err;
            }
            return payload.data;
        });
    }

    // ---------------------------------------------------------------------
    // Status line (shared with settings page styling)
    // ---------------------------------------------------------------------

    const $status = $root.find('[data-status]');
    let statusTimer = null;

    function flash(text, isError) {
        $status
            .text(text)
            .removeClass('text-green-700 text-red-700 bg-green-50 bg-red-50 border-green-200 border-red-200')
            .addClass(isError ? 'text-red-700 bg-red-50 border-red-200' : 'text-green-700 bg-green-50 border-green-200')
            .removeClass('opacity-0').addClass('opacity-100');
        clearTimeout(statusTimer);
        statusTimer = setTimeout(function () {
            $status.removeClass('opacity-100').addClass('opacity-0');
        }, 2500);
    }

    // ---------------------------------------------------------------------
    // Recompute worker row sum + capacity summary locally
    // ---------------------------------------------------------------------

    function recomputeRow(swId, commitMap) {
        const $row = $root.find('[data-sw-row][data-sw-id="' + swId + '"]');
        let sum = 0;
        $row.find('[data-day]').each(function () {
            const v = Number($(this).val());
            if (!Number.isNaN(v)) { sum += v; }
        });

        const committed = (commitMap || committedPrio1FromDom())[String(swId)] || 0;
        const cap = capacity(sum, committed);

        $row.find('[data-sum-days]').text(fmtDays(cap.ressourcen));
        $root.find('[data-cap-ressourcen][data-sw-id="' + swId + '"]').text(fmtDays(cap.ressourcen));
        $root.find('[data-cap-after-reserves][data-sw-id="' + swId + '"]').text(fmtDays(cap.afterReserves));

        const $avail = $root.find('[data-cap-available][data-sw-id="' + swId + '"]');
        $avail.text(fmtDays(cap.available));
        if (cap.available < 0) {
            $avail.removeClass('text-slate-900').addClass('text-red-700');
        } else {
            $avail.removeClass('text-red-700').addClass('text-slate-900');
        }
    }

    // Recompute every worker row (capacity summary) — called when a task-side
    // change might affect committed prio-1 values.
    function recomputeAllCapacity() {
        const commit = committedPrio1FromDom();
        $root.find('[data-sw-row]').each(function () {
            recomputeRow(parseInt($(this).data('sw-id'), 10), commit);
        });
    }

    function recomputeSumMax() {
        let sum = 0;
        $root.find('[data-week-max]').each(function () {
            const v = Number($(this).val());
            if (!Number.isNaN(v)) { sum += v; }
        });
        $root.find('[data-sum-max]').text(fmtDays(sum));
    }

    // ---------------------------------------------------------------------
    // Pending-cell queue, debounced batch save
    // ---------------------------------------------------------------------

    // key = "swId:weekId" → { sw_id, week_id, days }
    const pendingCells = new Map();
    let cellDebounce = null;

    function queueCell(swId, weekId, days) {
        pendingCells.set(swId + ':' + weekId, {
            sprint_worker_id: swId,
            sprint_week_id:   weekId,
            days:             days,
        });
        clearTimeout(cellDebounce);
        cellDebounce = setTimeout(flushCells, 400);
    }

    function flushCells() {
        if (pendingCells.size === 0) { return; }
        const cells = Array.from(pendingCells.values());
        pendingCells.clear();

        request('PATCH', '/sprints/' + sprintId + '/week-cells', cells)
            .then(function (data) {
                if (data.applied === 0 && data.noop > 0) {
                    flash('No changes');
                } else {
                    flash('Saved ' + data.applied + (data.applied === 1 ? ' cell' : ' cells'));
                }
                // Trust the server's capacity numbers — same formula, but a
                // safety net if an input was tampered with.
                if (data.per_worker && typeof data.per_worker === 'object') {
                    Object.keys(data.per_worker).forEach(function (swIdStr) {
                        const c = data.per_worker[swIdStr];
                        $root.find('[data-cap-ressourcen][data-sw-id="' + swIdStr + '"]').text(fmtDays(c.ressourcen));
                        $root.find('[data-cap-after-reserves][data-sw-id="' + swIdStr + '"]').text(fmtDays(c.after_reserves));
                        const $av = $root.find('[data-cap-available][data-sw-id="' + swIdStr + '"]');
                        $av.text(fmtDays(c.available));
                        if (c.available < 0) {
                            $av.removeClass('text-slate-900').addClass('text-red-700');
                        } else {
                            $av.removeClass('text-red-700').addClass('text-slate-900');
                        }
                        $root.find('[data-sw-row][data-sw-id="' + swIdStr + '"] [data-sum-days]').text(fmtDays(c.ressourcen));
                    });
                }
            })
            .catch(function (e) { flash(e.message, true); });
    }

    // ---------------------------------------------------------------------
    // Day cells
    // ---------------------------------------------------------------------

    $root.on('blur change', '[data-day]', function () {
        const $el = $(this);
        let v = Number($el.val());
        if (Number.isNaN(v)) { v = 0; }
        if (v < 0) { v = 0; }
        if (v > 5) { v = 5; }
        v = snap05(v);
        $el.val(fmtDays(v));

        const swId   = parseInt($el.data('sw-id'), 10);
        const weekId = parseInt($el.data('week-id'), 10);
        queueCell(swId, weekId, v);
        recomputeRow(swId);
    });

    // ---------------------------------------------------------------------
    // Max working days (Arbeitstage row)
    // ---------------------------------------------------------------------

    $root.on('blur change', '[data-week-max]', function () {
        const $el = $(this);
        let v = Number($el.val());
        if (Number.isNaN(v)) { v = 0; }
        if (v < 0) { v = 0; }
        if (v > 5) { v = 5; }
        v = snap05(v);
        $el.val(fmtDays(v));

        const weekId = parseInt($el.data('week-id'), 10);
        recomputeSumMax();

        request('PATCH', '/sprints/' + sprintId + '/week/' + weekId, { max_working_days: v })
            .then(function () { flash('Saved'); })
            .catch(function (e) { flash(e.message, true); });
    });

    // ---------------------------------------------------------------------
    // Per-row RTB edit
    // ---------------------------------------------------------------------

    $root.on('blur change', '[data-rtb]', function () {
        const $el = $(this);
        let v = Number($el.val());
        if (Number.isNaN(v)) { v = 0; }
        if (v < 0) { v = 0; }
        if (v > 1) { v = 1; }
        v = snap005(v);
        $el.val(fmtRtb(v));

        const swId = parseInt($el.data('sw-id'), 10);
        request('PATCH', '/sprints/' + sprintId + '/workers/' + swId, { rtb: v })
            .then(function () { flash('Saved'); })
            .catch(function (e) { flash(e.message, true); });
    });

    // ---------------------------------------------------------------------
    // Worker row drag-reorder (admin only — tbody only exists with handles)
    // ---------------------------------------------------------------------

    const sortableAvailable = typeof $.fn.sortable === 'function';
    if (!sortableAvailable) {
        // jQuery UI didn't load (SRI mismatch, offline CDN, ad blocker).
        // Drag-reorder is unavailable but the rest of the page still works.
        // eslint-disable-next-line no-console
        console.warn('[sprint-planner] jQuery UI not loaded — drag reorder disabled.');
    }

    const $tbody = $root.find('[data-tbody]');
    if (sortableAvailable && $tbody.find('.handle').length > 0) {
        $tbody.sortable({
            handle: '.handle',
            items:  'tr[data-sw-row]',
            axis:   'y',
            helper: function (e, tr) {
                // Preserve the td widths so the row doesn't collapse while dragging.
                const $cells = tr.children();
                const $clone = tr.clone();
                $clone.children().each(function (i) { $(this).width($cells.eq(i).width()); });
                return $clone;
            },
            update: function () {
                const ordering = $tbody.find('tr[data-sw-row]').map(function (i, el) {
                    return {
                        sprint_worker_id: parseInt($(el).data('sw-id'), 10),
                        sort_order:       i + 1,
                    };
                }).get();

                request('POST', '/sprints/' + sprintId + '/workers/reorder', ordering)
                    .then(function (data) {
                        if (data.moved) {
                            // Column order in the task list below depends on
                            // this ordering — simplest to re-render.
                            window.location.reload();
                        } else {
                            flash('No changes');
                        }
                    })
                    .catch(function (e) { flash(e.message, true); });
            },
        });
    }

    // =====================================================================
    // Task list — create/edit/delete/reorder + assignments + filter/sort
    // =====================================================================

    const $taskTbody = $root.find('[data-task-tbody]');
    const hasTaskUi  = $taskTbody.length > 0;

    // --- Worker/owner helpers read from the DOM once ----------------------

    function sprintWorkerHeaders() {
        const out = [];
        $root.find('[data-task-table] thead th[data-sort-col^="sw-"]').each(function () {
            const col = String($(this).attr('data-sort-col'));
            out.push({
                id:   parseInt(col.slice(3), 10),
                name: $(this).clone().children().remove().end().text().trim(),
            });
        });
        return out;
    }

    function ownerChoices() {
        const out = [];
        $root.find('[data-owner-filter] option').each(function () {
            const v = $(this).val();
            if (v === '' || v === '__none__') { return; }
            out.push({ id: parseInt(String(v), 10), name: String($(this).text()).trim() });
        });
        return out;
    }

    // --- Build a task row <tr> from an object ----------------------------

    function buildTaskRow(task, assignments) {
        assignments = assignments || {};
        const $tr = $('<tr>')
            .attr('data-task-row', '')
            .attr('data-task-id', task.id)
            .attr('data-prio', task.priority)
            .attr('data-owner', task.owner_worker_id || '')
            .attr('data-sort-order', task.sort_order);

        // handle
        $tr.append($('<td class="px-2 py-1"></td>').append(
            $('<span class="handle cursor-grab text-slate-400 select-none">').html('&#8801;')
        ));

        // title
        $tr.append(
            $('<td class="px-2 py-1 min-w-[14rem]"></td>').append(
                $('<input type="text" data-title class="w-full rounded border border-slate-200 px-2 py-1 focus:outline-none focus:ring-2 focus:ring-slate-400">')
                    .val(task.title)
            )
        );

        // owner
        const $sel = $('<select data-owner-select class="w-full rounded border border-slate-200 px-2 py-1 bg-white focus:outline-none focus:ring-2 focus:ring-slate-400">');
        $sel.append('<option value="">—</option>');
        ownerChoices().forEach(function (o) {
            const $opt = $('<option>').val(o.id).text(o.name);
            if (Number(o.id) === Number(task.owner_worker_id)) { $opt.attr('selected', 'selected'); }
            $sel.append($opt);
        });
        $tr.append($('<td class="px-2 py-1"></td>').append($sel));

        // priority
        const $prio = $('<select data-prio-select class="rounded border border-slate-200 px-2 py-1 bg-white font-mono focus:outline-none focus:ring-2 focus:ring-slate-400"><option value="1">1</option><option value="2">2</option></select>');
        $prio.val(String(task.priority));
        $tr.append($('<td class="px-2 py-1 text-center"></td>').append($prio));

        // tot
        let tot = 0;
        Object.keys(assignments).forEach(function (k) { tot += Number(assignments[k]) || 0; });
        $tr.append($('<td class="px-2 py-1 text-center font-mono font-semibold" data-task-tot>').text(fmtDays(tot)));

        // per-worker assignment cells
        sprintWorkerHeaders().forEach(function (sw) {
            const v = Number(assignments[sw.id] || 0);
            const $td = $('<td class="px-1 py-1 text-center"></td>')
                .attr('data-sort-value-sw-' + sw.id, v.toFixed(2));
            $td.append(
                $('<input type="number" min="0" step="0.5" data-assign class="w-14 rounded border border-slate-200 px-1 py-1 text-center font-mono focus:outline-none focus:ring-2 focus:ring-slate-400">')
                    .val(fmtDays(v))
                    .attr('data-sw-id', sw.id)
            );
            $tr.append($td);
        });

        // delete
        $tr.append(
            $('<td class="px-1 py-1 text-right"></td>').append(
                $('<button type="button" data-delete-task class="text-sm text-red-600 hover:underline">').text('×')
            )
        );

        return $tr;
    }

    // --- Add task ---------------------------------------------------------

    $root.on('click', '[data-add-task]', function () {
        request('POST', '/sprints/' + sprintId + '/tasks', { title: '', priority: 1 })
            .then(function (data) {
                $root.find('[data-empty-tasks]').remove();
                const $row = buildTaskRow(data.task, data.assignments || {});
                $taskTbody.append($row);
                // Clear any active sort so the new row is actually visible at the end.
                clearSort();
                applyFilters();
                $row.find('[data-title]').trigger('focus').trigger('select');
                flash('Task added');
            })
            .catch(function (e) { flash(e.message, true); });
    });

    // --- Edit task fields (title / owner / prio) --------------------------

    const titleDebounce = {};
    $root.on('input', '[data-title]', function () {
        const $inp = $(this);
        const taskId = parseInt($inp.closest('tr').data('task-id'), 10);
        clearTimeout(titleDebounce[taskId]);
        titleDebounce[taskId] = setTimeout(function () {
            const title = String($inp.val()).trim();
            if (title === '') {
                flash('Title cannot be empty', true);
                return;
            }
            request('PATCH', '/tasks/' + taskId, { title: title })
                .then(function () { flash('Saved'); })
                .catch(function (e) { flash(e.message, true); });
        }, 400);
    });

    $root.on('change', '[data-owner-select]', function () {
        const $sel = $(this);
        const $row = $sel.closest('tr');
        const taskId = parseInt($row.data('task-id'), 10);
        const v = $sel.val();
        const owner = v === '' ? null : parseInt(String(v), 10);
        $row.attr('data-owner', owner === null ? '' : owner);

        request('PATCH', '/tasks/' + taskId, { owner_worker_id: owner })
            .then(function () { flash('Saved'); applyFilters(); })
            .catch(function (e) { flash(e.message, true); });
    });

    $root.on('change', '[data-prio-select]', function () {
        const $sel = $(this);
        const $row = $sel.closest('tr');
        const taskId = parseInt($row.data('task-id'), 10);
        const prio = parseInt(String($sel.val()), 10);
        $row.attr('data-prio', prio);

        request('PATCH', '/tasks/' + taskId, { priority: prio })
            .then(function (data) {
                flash('Saved');
                applyFilters();
                applyServerCapacity(data && data.per_worker);
                recomputeAllCapacity();
            })
            .catch(function (e) { flash(e.message, true); });
    });

    // --- Delete task ------------------------------------------------------

    $root.on('click', '[data-delete-task]', function () {
        const $row = $(this).closest('tr');
        const taskId = parseInt($row.data('task-id'), 10);
        const title  = $row.find('[data-title]').val() || '(untitled)';
        if (!window.confirm('Delete task "' + title + '"?')) { return; }

        request('DELETE', '/tasks/' + taskId)
            .then(function (data) {
                $row.remove();
                applyServerCapacity(data && data.per_worker);
                recomputeAllCapacity();
                flash('Task deleted');
                if ($taskTbody.children('tr[data-task-row]').length === 0) {
                    // Re-show the empty-state row (simpler than templating).
                    window.location.reload();
                }
            })
            .catch(function (e) { flash(e.message, true); });
    });

    // --- Assignment cells (per task, per sprint worker) -------------------
    // Same shape as the Arbeitstage cell queue, but against /tasks/{id}/assignments.

    const pendingAssign = new Map(); // taskId -> Map<swId, days>
    const assignTimers = {};

    function queueAssign(taskId, swId, days) {
        if (!pendingAssign.has(taskId)) { pendingAssign.set(taskId, new Map()); }
        pendingAssign.get(taskId).set(swId, days);
        clearTimeout(assignTimers[taskId]);
        assignTimers[taskId] = setTimeout(function () { flushAssign(taskId); }, 400);
    }

    function flushAssign(taskId) {
        const m = pendingAssign.get(taskId);
        if (!m || m.size === 0) { return; }
        const cells = [];
        m.forEach(function (days, swId) {
            cells.push({ sprint_worker_id: swId, days: days });
        });
        pendingAssign.delete(taskId);

        request('PATCH', '/tasks/' + taskId + '/assignments', cells)
            .then(function (data) {
                if (data.applied === 0 && data.noop > 0) { flash('No changes'); }
                else { flash('Saved ' + data.applied + (data.applied === 1 ? ' cell' : ' cells')); }
                applyServerCapacity(data && data.per_worker);
            })
            .catch(function (e) { flash(e.message, true); });
    }

    $root.on('blur change', '[data-assign]', function () {
        const $el = $(this);
        let v = Number($el.val());
        if (Number.isNaN(v) || v < 0) { v = 0; }
        v = snap05(v);
        $el.val(fmtDays(v));
        $el.closest('td').attr('data-sort-value-sw-' + $el.data('sw-id'), v.toFixed(2));

        const taskId = parseInt($el.closest('tr').data('task-id'), 10);
        const swId   = parseInt($el.data('sw-id'), 10);
        queueAssign(taskId, swId, v);

        // Row total
        let tot = 0;
        $el.closest('tr').find('[data-assign]').each(function () {
            const n = Number($(this).val());
            if (!Number.isNaN(n)) { tot += n; }
        });
        $el.closest('tr').find('[data-task-tot]').text(fmtDays(tot));

        // Available recompute (in case this is a prio-1 task)
        recomputeAllCapacity();
    });

    function applyServerCapacity(perWorker) {
        if (!perWorker || typeof perWorker !== 'object') { return; }
        Object.keys(perWorker).forEach(function (swIdStr) {
            const c = perWorker[swIdStr];
            $root.find('[data-cap-ressourcen][data-sw-id="' + swIdStr + '"]').text(fmtDays(c.ressourcen));
            $root.find('[data-cap-after-reserves][data-sw-id="' + swIdStr + '"]').text(fmtDays(c.after_reserves));
            const $av = $root.find('[data-cap-available][data-sw-id="' + swIdStr + '"]');
            $av.text(fmtDays(c.available));
            if (c.available < 0) {
                $av.removeClass('text-slate-900').addClass('text-red-700');
            } else {
                $av.removeClass('text-red-700').addClass('text-slate-900');
            }
        });
    }

    // --- Task reorder (drag) ----------------------------------------------

    if (sortableAvailable && hasTaskUi && $taskTbody.find('.handle').length > 0) {
        $taskTbody.sortable({
            handle: '.handle',
            items:  'tr[data-task-row]',
            axis:   'y',
            helper: function (e, tr) {
                const $cells = tr.children();
                const $clone = tr.clone();
                $clone.children().each(function (i) { $(this).width($cells.eq(i).width()); });
                return $clone;
            },
            start: function () {
                // Drag only makes sense when no sort is active.
                if (currentSort.col !== null) { clearSort(); }
            },
            update: function () {
                const ordering = $taskTbody.find('tr[data-task-row]').map(function (i, el) {
                    return { task_id: parseInt($(el).data('task-id'), 10), sort_order: i + 1 };
                }).get();

                request('POST', '/sprints/' + sprintId + '/tasks/reorder', ordering)
                    .then(function (data) {
                        ordering.forEach(function (o) {
                            $taskTbody.find('tr[data-task-id="' + o.task_id + '"]').attr('data-sort-order', o.sort_order);
                        });
                        flash(data.moved ? 'Order saved' : 'No changes');
                    })
                    .catch(function (e) { flash(e.message, true); });
            },
        });
    }

    // --- Filters (search / prio / owner) ----------------------------------

    function applyFilters() {
        const q         = String($root.find('[data-task-search]').val() || '').trim().toLowerCase();
        const prio      = String($root.find('[data-prio-filter]').val() || '');
        const owner     = String($root.find('[data-owner-filter]').val() || '');
        let visibleCount = 0;

        $taskTbody.children('tr[data-task-row]').each(function () {
            const $row      = $(this);
            const title     = String($row.find('[data-title]').val() || $row.find('[data-title]').text() || '').toLowerCase();
            const rowPrio   = String($row.attr('data-prio'));
            const rowOwner  = String($row.attr('data-owner') || '');

            let ok = true;
            if (q !== '' && !title.includes(q)) { ok = false; }
            if (prio !== '' && rowPrio !== prio) { ok = false; }
            if (owner === '__none__') {
                if (rowOwner !== '') { ok = false; }
            } else if (owner !== '' && rowOwner !== owner) {
                ok = false;
            }

            $row.toggle(ok);
            if (ok) { visibleCount++; }
        });

        const totalRows = $taskTbody.children('tr[data-task-row]').length;
        $root.find('[data-task-empty-filter]').toggle(totalRows > 0 && visibleCount === 0);
    }

    let searchDebounce = null;
    $root.on('input', '[data-task-search]', function () {
        clearTimeout(searchDebounce);
        searchDebounce = setTimeout(applyFilters, 120);
    });
    $root.on('change', '[data-prio-filter], [data-owner-filter]', applyFilters);

    // --- Column sort (client-side) ----------------------------------------

    const currentSort = { col: null, dir: null }; // dir: 'asc' | 'desc'

    function clearSort() {
        currentSort.col = null; currentSort.dir = null;
        $root.find('[data-sort-col]').each(function () {
            $(this).find('.sort-ind').text('↕').addClass('opacity-30').removeClass('opacity-100');
        });
        // Restore original order by data-sort-order
        const rows = $taskTbody.children('tr[data-task-row]').get();
        rows.sort(function (a, b) {
            return Number($(a).attr('data-sort-order')) - Number($(b).attr('data-sort-order'));
        });
        rows.forEach(function (el) { $taskTbody.append(el); });
    }

    function rowValueFor(col, $row) {
        if (col === 'title') {
            return String($row.find('[data-title]').val() || $row.find('[data-title]').text() || '').toLowerCase();
        }
        if (col === 'owner') {
            const id = String($row.attr('data-owner') || '');
            if (id === '') { return '\uFFFF'; } // sort empty last
            const opt = $row.find('[data-owner-select] option:selected');
            return String(opt.text() || '').toLowerCase();
        }
        if (col === 'prio') { return Number($row.attr('data-prio')); }
        if (col === 'tot')  { return Number($row.find('[data-task-tot]').text()) || 0; }
        if (col.indexOf('sw-') === 0) {
            const swId = col.slice(3);
            return Number($row.find('[data-assign][data-sw-id="' + swId + '"]').val()) || 0;
        }
        return 0;
    }

    function applySort(col) {
        let dir;
        if (currentSort.col !== col) { dir = 'asc'; }
        else if (currentSort.dir === 'asc') { dir = 'desc'; }
        else { clearSort(); return; } // third click clears

        currentSort.col = col;
        currentSort.dir = dir;

        $root.find('[data-sort-col] .sort-ind').text('↕').addClass('opacity-30').removeClass('opacity-100');
        $root.find('[data-sort-col="' + col + '"] .sort-ind')
            .text(dir === 'asc' ? '↑' : '↓')
            .removeClass('opacity-30').addClass('opacity-100');

        const rows = $taskTbody.children('tr[data-task-row]').get();
        rows.sort(function (a, b) {
            const va = rowValueFor(col, $(a));
            const vb = rowValueFor(col, $(b));
            if (va < vb) { return dir === 'asc' ? -1 : 1; }
            if (va > vb) { return dir === 'asc' ? 1 : -1; }
            // Stable-ish tiebreak: fall back to data-sort-order
            return Number($(a).attr('data-sort-order')) - Number($(b).attr('data-sort-order'));
        });
        rows.forEach(function (el) { $taskTbody.append(el); });
    }

    $root.on('click', '[data-sort-col]', function () {
        applySort(String($(this).attr('data-sort-col')));
    });

    // =====================================================================
    // Boot
    // =====================================================================

    // Recompute once at boot in case the server-rendered sums drift from the
    // JS formula (e.g. after a stale reload).
    $root.find('[data-sw-row]').each(function () {
        recomputeRow(parseInt($(this).data('sw-id'), 10));
    });
    recomputeSumMax();
    applyFilters();

})(jQuery);