From b76b4adaec35efff79a16653f9c1b331b30a08c6 Mon Sep 17 00:00:00 2001
From: Twyco <twyco@icloud.com>
Date: Fri, 11 Sep 2026 17:04:30 +0200
Subject: [PATCH] feat(KAN-29): rework backlog ticket tree

---
 resources/js/components/BacklogTicketTree.vue | 209 +++++++
 resources/js/components/TicketTreeList.vue    | 102 +++-
 .../js/components/tickets/TicketCard.vue      | 123 ++--
 resources/js/lib/backlog.ts                   | 114 ++++
 resources/js/locales/en.ts                    |  36 ++
 resources/js/pages/projects/Backlog.vue       | 565 +++++++++++++-----
 resources/js/types/backlog.ts                 |  31 +
 resources/js/types/index.ts                   |   2 +
 resources/js/types/ticket-presentation.ts     |   1 +
 resources/js/types/ticket-tree.ts             |   6 +
 tests/Feature/Projects/ProjectBacklogTest.php | 104 ++++
 11 files changed, 1050 insertions(+), 243 deletions(-)
 create mode 100644 resources/js/components/BacklogTicketTree.vue
 create mode 100644 resources/js/lib/backlog.ts
 create mode 100644 resources/js/types/backlog.ts
 create mode 100644 resources/js/types/ticket-tree.ts

diff --git a/resources/js/components/BacklogTicketTree.vue b/resources/js/components/BacklogTicketTree.vue
new file mode 100644
index 0000000..4e88173
--- /dev/null
+++ b/resources/js/components/BacklogTicketTree.vue
@@ -0,0 +1,209 @@
+<script setup lang="ts">
+import { Form } from '@inertiajs/vue3';
+import { ChevronDown, ChevronRight } from 'lucide-vue-next';
+import { move } from '@/actions/App/Http/Controllers/ProjectBoardController';
+import InputError from '@/components/InputError.vue';
+import { TicketCard } from '@/components/tickets';
+import { Badge } from '@/components/ui/badge';
+import { Button } from '@/components/ui/button';
+import { useLocalization } from '@/composables/useLocalization';
+import { ticketStatusLabel } from '@/lib/tickets';
+import type {
+    BacklogTicketTreeEmits,
+    BacklogTicketTreeProps,
+} from '@/types/backlog';
+import type { TicketModel } from '@/types/models/ticket-model';
+
+const props = defineProps<BacklogTicketTreeProps>();
+const emit = defineEmits<BacklogTicketTreeEmits>();
+const { t } = useLocalization();
+
+const allowedTargetStatuses = (ticket: TicketModel) =>
+    (ticket.ticket_status?.allowed_target_statuses ?? []).filter(
+        (status) => status.id !== ticket.ticket_status_id,
+    );
+</script>
+
+<template>
+    <ul class="grid min-w-0 gap-3">
+        <li v-for="node in nodes" :key="node.ticket.id" class="min-w-0">
+            <div class="grid min-w-0 grid-cols-[2.75rem_minmax(0,1fr)] gap-2">
+                <div class="flex justify-center pt-1">
+                    <button
+                        v-if="node.children.length > 0"
+                        type="button"
+                        class="border-border bg-card text-muted-foreground hover:border-primary hover:text-primary focus-visible:ring-ring/35 flex size-10 items-center justify-center rounded-md border transition-colors focus-visible:outline-none focus-visible:ring-2"
+                        :aria-expanded="!collapsedTicketIds.has(node.ticket.id)"
+                        :aria-controls="`backlog-children-${node.ticket.id}`"
+                        :aria-label="
+                            t(
+                                collapsedTicketIds.has(node.ticket.id)
+                                    ? 'backlog.tree.expand'
+                                    : 'backlog.tree.collapse',
+                                { key: node.ticket.ticket_key },
+                            )
+                        "
+                        @click="emit('toggle', node.ticket.id)"
+                    >
+                        <ChevronRight
+                            v-if="collapsedTicketIds.has(node.ticket.id)"
+                            class="size-4"
+                            aria-hidden="true"
+                        />
+                        <ChevronDown v-else class="size-4" aria-hidden="true" />
+                    </button>
+                    <span
+                        v-else
+                        class="bg-border mt-4 size-1.5 rounded-full"
+                        aria-hidden="true"
+                    />
+                </div>
+
+                <div class="grid min-w-0 gap-2">
+                    <Badge
+                        v-if="!node.matchesFilters"
+                        variant="secondary"
+                        class="w-fit"
+                    >
+                        {{ t('backlog.filters.parentContext') }}
+                    </Badge>
+
+                    <TicketCard
+                        :project-id="projectId"
+                        :ticket="node.ticket"
+                        layout="list"
+                        :class="{ 'opacity-80': !node.matchesFilters }"
+                    >
+                        <template v-if="canEditTickets" #actions>
+                            <Form
+                                v-bind="
+                                    move.form({
+                                        project: projectId,
+                                        ticket: node.ticket.id,
+                                    })
+                                "
+                                v-slot="{ processing, errors }"
+                                :error-bag="`backlog-ticket-${node.ticket.id}`"
+                                :options="{ preserveScroll: true }"
+                                :on-before="() => pendingTicketId === null"
+                                class="grid min-w-0 gap-2"
+                                @start="emit('moveStart', node.ticket.id)"
+                                @finish="emit('moveFinish', node.ticket.id)"
+                            >
+                                <input
+                                    type="hidden"
+                                    name="redirect_to"
+                                    value="backlog"
+                                />
+                                <label
+                                    :for="`backlog-ticket-status-${node.ticket.id}`"
+                                    class="text-caption text-muted-foreground font-semibold"
+                                >
+                                    {{
+                                        t('backlog.moveTicket', {
+                                            key: node.ticket.ticket_key,
+                                        })
+                                    }}
+                                </label>
+                                <select
+                                    :id="`backlog-ticket-status-${node.ticket.id}`"
+                                    name="ticket_status_id"
+                                    :disabled="
+                                        pendingTicketId !== null ||
+                                        processing ||
+                                        allowedTargetStatuses(node.ticket)
+                                            .length === 0
+                                    "
+                                    :aria-invalid="
+                                        !!errors.ticket_status_id || undefined
+                                    "
+                                    :aria-describedby="
+                                        errors.ticket_status_id
+                                            ? `backlog-ticket-status-error-${node.ticket.id}`
+                                            : undefined
+                                    "
+                                    class="border-input bg-card text-body min-h-control focus-visible:ring-ring/35 w-full min-w-0 rounded-md border px-3 py-2 focus-visible:outline-none focus-visible:ring-2 disabled:cursor-not-allowed disabled:opacity-60"
+                                >
+                                    <option
+                                        v-if="
+                                            allowedTargetStatuses(node.ticket)
+                                                .length === 0
+                                        "
+                                        value=""
+                                    >
+                                        {{ t('board.noMoves') }}
+                                    </option>
+                                    <option
+                                        v-for="target in allowedTargetStatuses(
+                                            node.ticket,
+                                        )"
+                                        :key="target.id"
+                                        :value="target.id"
+                                    >
+                                        {{
+                                            ticketStatusLabel(
+                                                target,
+                                                t('tickets.noStatus'),
+                                            )
+                                        }}
+                                    </option>
+                                </select>
+                                <InputError
+                                    :id="`backlog-ticket-status-error-${node.ticket.id}`"
+                                    :message="errors.ticket_status_id"
+                                />
+                                <Button
+                                    type="submit"
+                                    variant="outline"
+                                    :disabled="
+                                        pendingTicketId !== null ||
+                                        processing ||
+                                        allowedTargetStatuses(node.ticket)
+                                            .length === 0
+                                    "
+                                >
+                                    {{
+                                        t(
+                                            processing
+                                                ? 'board.updatingStatus'
+                                                : 'board.updateStatus',
+                                        )
+                                    }}
+                                </Button>
+                                <p
+                                    v-if="
+                                        allowedTargetStatuses(node.ticket)
+                                            .length === 0
+                                    "
+                                    class="text-caption text-muted-foreground"
+                                >
+                                    {{ t('board.noMovesDescription') }}
+                                </p>
+                            </Form>
+                        </template>
+                    </TicketCard>
+                </div>
+            </div>
+
+            <div
+                v-if="
+                    node.children.length > 0 &&
+                    !collapsedTicketIds.has(node.ticket.id)
+                "
+                :id="`backlog-children-${node.ticket.id}`"
+                class="border-border ml-[1.375rem] mt-3 border-l pl-2 sm:pl-4"
+            >
+                <BacklogTicketTree
+                    :nodes="node.children"
+                    :project-id="projectId"
+                    :can-edit-tickets="canEditTickets"
+                    :collapsed-ticket-ids="collapsedTicketIds"
+                    :pending-ticket-id="pendingTicketId"
+                    @toggle="emit('toggle', $event)"
+                    @move-start="emit('moveStart', $event)"
+                    @move-finish="emit('moveFinish', $event)"
+                />
+            </div>
+        </li>
+    </ul>
+</template>
diff --git a/resources/js/components/TicketTreeList.vue b/resources/js/components/TicketTreeList.vue
index 3c35639..180e7d9 100644
--- a/resources/js/components/TicketTreeList.vue
+++ b/resources/js/components/TicketTreeList.vue
@@ -1,45 +1,93 @@
 <script setup lang="ts">
 import { Link } from '@inertiajs/vue3';
+import { ChevronDown, ChevronRight } from 'lucide-vue-next';
+import { reactive } from 'vue';
 import { Badge } from '@/components/ui/badge';
+import { useLocalization } from '@/composables/useLocalization';
 import { show as showTicket } from '@/routes/projects/tickets';
-import type { TicketTreeNodeModel } from '@/types/models/ticket-tree-node-model';
+import type { TicketTreeListProps } from '@/types/ticket-tree';
 
-defineProps<{
-    nodes: TicketTreeNodeModel[];
-    projectId: number;
-}>();
+defineProps<TicketTreeListProps>();
+
+const { t } = useLocalization();
+const collapsedTicketIds = reactive(new Set<number>());
+
+function toggleTicket(ticketId: number): void {
+    if (collapsedTicketIds.has(ticketId)) {
+        collapsedTicketIds.delete(ticketId);
+    } else {
+        collapsedTicketIds.add(ticketId);
+    }
+}
 </script>
 
 <template>
-    <ul class="space-y-3">
-        <li v-for="node in nodes" :key="node.id">
-            <div class="border-border rounded-xl border px-4 py-4">
-                <div class="flex flex-wrap items-center gap-2">
-                    <Link
-                        :href="
-                            showTicket({
-                                project: projectId,
-                                ticket: node.id,
-                            })
+    <ul class="grid min-w-0 gap-3">
+        <li v-for="node in nodes" :key="node.id" class="min-w-0">
+            <div class="grid min-w-0 grid-cols-[2.75rem_minmax(0,1fr)] gap-2">
+                <div class="flex justify-center pt-1">
+                    <button
+                        v-if="node.children.length > 0"
+                        type="button"
+                        class="border-border bg-card text-muted-foreground hover:border-primary hover:text-primary focus-visible:ring-ring/35 flex size-10 items-center justify-center rounded-md border transition-colors focus-visible:outline-none focus-visible:ring-2"
+                        :aria-expanded="!collapsedTicketIds.has(node.id)"
+                        :aria-controls="`ticket-tree-children-${node.id}`"
+                        :aria-label="
+                            t(
+                                collapsedTicketIds.has(node.id)
+                                    ? 'tickets.tree.expand'
+                                    : 'tickets.tree.collapse',
+                                { key: node.ticket_key },
+                            )
                         "
-                        class="text-foreground hover:text-primary font-medium transition"
+                        @click="toggleTicket(node.id)"
                     >
-                        {{ node.ticket_key }}
-                    </Link>
-
-                    <Badge v-if="node.ticket_type_name" variant="secondary">
-                        {{ node.ticket_type_name }}
-                    </Badge>
+                        <ChevronRight
+                            v-if="collapsedTicketIds.has(node.id)"
+                            class="size-4"
+                            aria-hidden="true"
+                        />
+                        <ChevronDown v-else class="size-4" aria-hidden="true" />
+                    </button>
+                    <span
+                        v-else
+                        class="bg-border mt-4 size-1.5 rounded-full"
+                        aria-hidden="true"
+                    />
                 </div>
 
-                <div class="text-foreground mt-2 text-sm">
-                    {{ node.title }}
-                </div>
+                <Link
+                    :href="
+                        showTicket({
+                            project: projectId,
+                            ticket: node.id,
+                        })
+                    "
+                    class="bg-card text-card-foreground hover:border-primary focus-visible:ring-ring/35 gap-stack group grid min-w-0 rounded-md border p-4 transition-[border-color,box-shadow] focus-visible:outline-none focus-visible:ring-2"
+                >
+                    <div class="flex min-w-0 flex-wrap items-center gap-2">
+                        <Badge variant="outline">
+                            {{ node.ticket_key }}
+                        </Badge>
+                        <Badge v-if="node.ticket_type_name" variant="secondary">
+                            {{ node.ticket_type_name }}
+                        </Badge>
+                    </div>
+
+                    <span
+                        class="text-body group-hover:text-primary wrap-anywhere min-w-0 font-semibold"
+                    >
+                        {{ node.title }}
+                    </span>
+                </Link>
             </div>
 
             <div
-                v-if="node.children.length > 0"
-                class="border-border mt-3 border-l pl-4"
+                v-if="
+                    node.children.length > 0 && !collapsedTicketIds.has(node.id)
+                "
+                :id="`ticket-tree-children-${node.id}`"
+                class="border-border ml-[1.375rem] mt-3 border-l pl-2 sm:pl-4"
             >
                 <TicketTreeList
                     :nodes="node.children"
diff --git a/resources/js/components/tickets/TicketCard.vue b/resources/js/components/tickets/TicketCard.vue
index d5b00b5..2517f9d 100644
--- a/resources/js/components/tickets/TicketCard.vue
+++ b/resources/js/components/tickets/TicketCard.vue
@@ -11,6 +11,7 @@ import type {
 } from '@/types/ticket-presentation';
 
 withDefaults(defineProps<TicketPresentationProps>(), {
+    layout: 'card',
     showDescription: true,
     showStatus: true,
 });
@@ -22,63 +23,85 @@ const { t } = useLocalization();
 <template>
     <article
         :class="[
-            'bg-card text-card-foreground min-w-0 rounded-md border shadow-sm',
+            'bg-card text-card-foreground min-w-0 rounded-md border',
+            layout === 'card' ? 'shadow-sm' : '',
             ticket.is_blocked ? 'border-warning' : 'border-border',
         ]"
     >
-        <Link
-            :href="showTicket({ project: projectId, ticket: ticket.id })"
-            :aria-label="
-                t('tickets.open', {
-                    key: ticket.ticket_key,
-                    title: ticket.title,
-                })
+        <div
+            :class="
+                layout === 'list'
+                    ? 'flex min-w-0 flex-col lg:flex-row lg:items-stretch'
+                    : ''
             "
-            class="focus-visible:ring-ring/35 gap-card min-h-control hover:bg-accent/35 group flex min-w-0 flex-col rounded-t-md p-4 transition-[background-color,box-shadow] focus-visible:outline-none focus-visible:ring-2"
-            @click="emit('open', ticket.id)"
         >
-            <div class="flex min-w-0 items-start justify-between gap-3">
-                <Badge
-                    variant="outline"
-                    class="wrap-anywhere max-w-full whitespace-normal"
-                >
-                    {{ ticket.ticket_key }}
-                </Badge>
-                <ArrowUpRight
-                    class="text-muted-foreground group-hover:text-primary size-4 shrink-0"
-                    aria-hidden="true"
-                />
-            </div>
-
-            <h3
-                class="text-body group-hover:text-primary wrap-anywhere min-w-0 font-semibold"
-            >
-                {{ ticket.title }}
-            </h3>
-
-            <TicketMetadata :ticket="ticket" :show-status="showStatus" />
-
-            <p
-                v-if="showDescription && ticket.description"
-                class="text-caption text-muted-foreground wrap-anywhere line-clamp-3"
-            >
-                {{ ticket.description }}
-            </p>
-
-            <p
-                v-if="ticket.is_blocked && ticket.blocked_comment"
-                class="text-caption text-warning-foreground bg-warning wrap-anywhere rounded-sm px-3 py-2"
-            >
-                {{
-                    t('tickets.blockerComment', {
-                        comment: ticket.blocked_comment,
+            <Link
+                :href="showTicket({ project: projectId, ticket: ticket.id })"
+                :aria-label="
+                    t('tickets.open', {
+                        key: ticket.ticket_key,
+                        title: ticket.title,
                     })
-                }}
-            </p>
-        </Link>
+                "
+                :class="[
+                    'focus-visible:ring-ring/35 gap-card min-h-control hover:bg-accent/35 group flex min-w-0 flex-1 flex-col p-4 transition-[background-color,box-shadow] focus-visible:outline-none focus-visible:ring-2',
+                    layout === 'list'
+                        ? 'rounded-t-md lg:rounded-l-md lg:rounded-tr-none'
+                        : 'rounded-t-md',
+                ]"
+                @click="emit('open', ticket.id)"
+            >
+                <div class="flex min-w-0 items-start justify-between gap-3">
+                    <Badge
+                        variant="outline"
+                        class="wrap-anywhere max-w-full whitespace-normal"
+                    >
+                        {{ ticket.ticket_key }}
+                    </Badge>
+                    <ArrowUpRight
+                        class="text-muted-foreground group-hover:text-primary size-4 shrink-0"
+                        aria-hidden="true"
+                    />
+                </div>
 
-        <div v-if="$slots.actions" class="border-t p-4">
-            <slot name="actions" />
+                <h3
+                    class="text-body group-hover:text-primary wrap-anywhere min-w-0 font-semibold"
+                >
+                    {{ ticket.title }}
+                </h3>
+
+                <TicketMetadata :ticket="ticket" :show-status="showStatus" />
+
+                <p
+                    v-if="showDescription && ticket.description"
+                    class="text-caption text-muted-foreground wrap-anywhere line-clamp-3"
+                >
+                    {{ ticket.description }}
+                </p>
+
+                <p
+                    v-if="ticket.is_blocked && ticket.blocked_comment"
+                    class="text-caption text-warning-foreground bg-warning wrap-anywhere rounded-sm px-3 py-2"
+                >
+                    {{
+                        t('tickets.blockerComment', {
+                            comment: ticket.blocked_comment,
+                        })
+                    }}
+                </p>
+            </Link>
+
+            <div
+                v-if="$slots.actions"
+                :class="[
+                    'border-t p-4',
+                    layout === 'list'
+                        ? 'lg:flex lg:w-80 lg:items-center lg:border-l lg:border-t-0'
+                        : '',
+                ]"
+            >
+                <slot name="actions" />
+            </div>
         </div>
     </article>
 </template>
diff --git a/resources/js/lib/backlog.ts b/resources/js/lib/backlog.ts
new file mode 100644
index 0000000..4c6e02b
--- /dev/null
+++ b/resources/js/lib/backlog.ts
@@ -0,0 +1,114 @@
+import type {
+    BacklogFilterState,
+    BacklogTicketTreeNode,
+} from '@/types/backlog';
+import type { TicketModel } from '@/types/models/ticket-model';
+
+export function buildBacklogTicketTree(
+    tickets: TicketModel[],
+): BacklogTicketTreeNode[] {
+    const nodesByTicketId = new Map<number, BacklogTicketTreeNode>();
+
+    for (const ticket of tickets) {
+        nodesByTicketId.set(ticket.id, {
+            children: [],
+            matchesFilters: true,
+            ticket,
+        });
+    }
+
+    const roots: BacklogTicketTreeNode[] = [];
+
+    for (const ticket of tickets) {
+        const node = nodesByTicketId.get(ticket.id);
+
+        if (!node) {
+            continue;
+        }
+
+        const parentNode =
+            ticket.parent_ticket_id === null
+                ? undefined
+                : nodesByTicketId.get(ticket.parent_ticket_id);
+
+        if (parentNode) {
+            parentNode.children.push(node);
+        } else {
+            roots.push(node);
+        }
+    }
+
+    return roots;
+}
+
+export function filterBacklogTicketTree(
+    nodes: BacklogTicketTreeNode[],
+    filters: BacklogFilterState,
+): BacklogTicketTreeNode[] {
+    return nodes.flatMap((node) => {
+        const children = filterBacklogTicketTree(node.children, filters);
+        const matchesFilters = ticketMatchesFilters(node.ticket, filters);
+
+        if (!matchesFilters && children.length === 0) {
+            return [];
+        }
+
+        return [
+            {
+                ...node,
+                children,
+                matchesFilters,
+            },
+        ];
+    });
+}
+
+export function countBacklogTreeTickets(
+    nodes: BacklogTicketTreeNode[],
+): number {
+    return nodes.reduce(
+        (count, node) => count + 1 + countBacklogTreeTickets(node.children),
+        0,
+    );
+}
+
+export function expandableBacklogTicketIds(
+    nodes: BacklogTicketTreeNode[],
+): number[] {
+    return nodes.flatMap((node) => [
+        ...(node.children.length > 0 ? [node.ticket.id] : []),
+        ...expandableBacklogTicketIds(node.children),
+    ]);
+}
+
+function ticketMatchesFilters(
+    ticket: TicketModel,
+    filters: BacklogFilterState,
+): boolean {
+    const query = filters.query.trim().toLocaleLowerCase();
+    const searchableText = [
+        ticket.ticket_key,
+        ticket.title,
+        ticket.description,
+        ticket.ticket_type.name,
+        ticket.ticket_priority.name,
+        ticket.ticket_status?.name,
+        ticket.assignee?.name,
+    ]
+        .filter((value): value is string => Boolean(value))
+        .join(' ')
+        .toLocaleLowerCase();
+
+    return (
+        (query === '' || searchableText.includes(query)) &&
+        (filters.typeId === '' || ticket.ticket_type_id === filters.typeId) &&
+        (filters.priorityId === '' ||
+            ticket.ticket_priority_id === filters.priorityId) &&
+        (filters.statusId === '' ||
+            ticket.ticket_status_id === filters.statusId) &&
+        (filters.assigneeId === '' ||
+            (filters.assigneeId === 'unassigned'
+                ? ticket.assignee_user_id === null
+                : ticket.assignee_user_id === filters.assigneeId))
+    );
+}
diff --git a/resources/js/locales/en.ts b/resources/js/locales/en.ts
index 79b3837..980c092 100644
--- a/resources/js/locales/en.ts
+++ b/resources/js/locales/en.ts
@@ -31,6 +31,40 @@ export const en = {
     'board.targetStatus': 'Destination status',
     'board.noMovesDescription':
         'This status does not allow moving anywhere else.',
+    'backlog.title': '{name} backlog',
+    'backlog.description':
+        'Shape incoming work without losing sight of parent and child tickets.',
+    'backlog.openBoard': 'Open board',
+    'backlog.backToProject': 'Project overview',
+    'backlog.moveTicket': 'Move {key}',
+    'backlog.filters.title': 'Find backlog tickets',
+    'backlog.filters.description':
+        'Filter this view locally. Matching child tickets keep their parent context visible.',
+    'backlog.filters.search': 'Search',
+    'backlog.filters.searchPlaceholder': 'Key, title, description, or metadata',
+    'backlog.filters.type': 'Type',
+    'backlog.filters.allTypes': 'All types',
+    'backlog.filters.priority': 'Priority',
+    'backlog.filters.allPriorities': 'All priorities',
+    'backlog.filters.status': 'Status',
+    'backlog.filters.allStatuses': 'All backlog statuses',
+    'backlog.filters.assignee': 'Assignee',
+    'backlog.filters.allAssignees': 'All assignees',
+    'backlog.filters.clear': 'Clear filters',
+    'backlog.filters.parentContext': 'Parent context',
+    'backlog.filters.empty.title': 'No tickets match these filters',
+    'backlog.filters.empty.description':
+        'Try a broader search or clear the filters to see the complete backlog.',
+    'backlog.results.title': 'Backlog tickets',
+    'backlog.results.count': 'Showing {count} of {total} tickets',
+    'backlog.empty.title': 'Your backlog is clear',
+    'backlog.empty.description':
+        'New tickets without a workflow column will appear here.',
+    'backlog.empty.action': 'Create the first ticket',
+    'backlog.tree.expand': 'Expand children of {key}',
+    'backlog.tree.collapse': 'Collapse children of {key}',
+    'backlog.tree.expandAll': 'Expand all',
+    'backlog.tree.collapseAll': 'Collapse all',
     'projectCreation.title': 'Create a project',
     'projectCreation.description':
         'Give your work a home. Start fresh or reuse a setup that already works for your team.',
@@ -356,6 +390,8 @@ export const en = {
     'tickets.noStatus': 'No status',
     'tickets.assignedTo': 'Assigned to {name}',
     'tickets.unassigned': 'Unassigned',
+    'tickets.tree.expand': 'Expand children of {key}',
+    'tickets.tree.collapse': 'Collapse children of {key}',
     'common.save': 'Save',
     'common.loading': 'Loading…',
     'common.error': 'Something went wrong.',
diff --git a/resources/js/pages/projects/Backlog.vue b/resources/js/pages/projects/Backlog.vue
index f93e7e1..145303c 100644
--- a/resources/js/pages/projects/Backlog.vue
+++ b/resources/js/pages/projects/Backlog.vue
@@ -1,70 +1,155 @@
 <script setup lang="ts">
-import { Form, Head, Link } from '@inertiajs/vue3';
-import ProjectBoardController from '@/actions/App/Http/Controllers/ProjectBoardController';
-import Heading from '@/components/Heading.vue';
-import { TicketListItem } from '@/components/tickets';
+import { Head, Link } from '@inertiajs/vue3';
+import {
+    ArrowLeft,
+    ChevronsDownUp,
+    ChevronsUpDown,
+    Columns3,
+    Plus,
+    RotateCcw,
+    Search,
+} from 'lucide-vue-next';
+import { computed, reactive, ref, watch } from 'vue';
+import BacklogTicketTree from '@/components/BacklogTicketTree.vue';
+import FeedbackState from '@/components/FeedbackState.vue';
 import { Badge } from '@/components/ui/badge';
 import { Button } from '@/components/ui/button';
-import {
-    Card,
-    CardContent,
-    CardDescription,
-    CardHeader,
-    CardTitle,
-} from '@/components/ui/card';
+import { useLocalization } from '@/composables/useLocalization';
 import AppLayout from '@/layouts/AppLayout.vue';
-import { ticketStatusLabel } from '@/lib/tickets';
+import {
+    buildBacklogTicketTree,
+    countBacklogTreeTickets,
+    expandableBacklogTicketIds,
+    filterBacklogTicketTree,
+} from '@/lib/backlog';
 import { index as boardIndex } from '@/routes/projects/board';
 import { index as backlogIndex } from '@/routes/projects/backlog';
-import { index, show } from '@/routes/projects/index';
+import { index as projectIndex, show } from '@/routes/projects/index';
 import { create as createTicket } from '@/routes/projects/tickets';
-import type { BreadcrumbItem, ProjectBacklogPageProps } from '@/types';
-import type { TicketModel } from '@/types/models/ticket-model';
-import type { TicketStatusModel } from '@/types/models/ticket-status-model';
+import type {
+    BacklogFilterState,
+    BreadcrumbItem,
+    ProjectBacklogPageProps,
+} from '@/types';
 
 const props = defineProps<ProjectBacklogPageProps>();
+const { t } = useLocalization();
+const breadcrumbs = computed<BreadcrumbItem[]>(() => [
+    { title: t('navigation.projects'), href: projectIndex() },
+    { title: props.project.name, href: show(props.project.id) },
+    { title: t('navigation.backlog'), href: backlogIndex(props.project.id) },
+]);
 
-const breadcrumbs: BreadcrumbItem[] = [
-    {
-        title: 'Projects',
-        href: index(),
-    },
-    {
-        title: props.project.name,
-        href: show(props.project.id),
-    },
-    {
-        title: 'Backlog',
-        href: backlogIndex(props.project.id),
-    },
-];
+const filters = reactive<BacklogFilterState>({
+    assigneeId: '',
+    priorityId: '',
+    query: '',
+    statusId: '',
+    typeId: '',
+});
+const collapsedTicketIds = reactive(new Set<number>());
+const pendingTicketId = ref<number | null>(null);
+const ticketTree = computed(() => buildBacklogTicketTree(props.tickets));
+const filteredTicketTree = computed(() =>
+    filterBacklogTicketTree(ticketTree.value, filters),
+);
+const visibleTicketCount = computed(() =>
+    countBacklogTreeTickets(filteredTicketTree.value),
+);
+const expandableTicketIds = computed(() =>
+    expandableBacklogTicketIds(filteredTicketTree.value),
+);
+const hasActiveFilters = computed(
+    () =>
+        filters.query.trim() !== '' ||
+        filters.typeId !== '' ||
+        filters.priorityId !== '' ||
+        filters.statusId !== '' ||
+        filters.assigneeId !== '',
+);
+const allVisibleBranchesCollapsed = computed(
+    () =>
+        expandableTicketIds.value.length > 0 &&
+        expandableTicketIds.value.every((ticketId) =>
+            collapsedTicketIds.has(ticketId),
+        ),
+);
 
-const allowedTargetStatuses = (ticket: TicketModel): TicketStatusModel[] => {
-    return (ticket.ticket_status?.allowed_target_statuses ?? []).filter(
-        (ticketStatus) => ticketStatus.id !== ticket.ticket_status_id,
-    );
-};
+function clearFilters(): void {
+    filters.query = '';
+    filters.typeId = '';
+    filters.priorityId = '';
+    filters.statusId = '';
+    filters.assigneeId = '';
+}
+
+function toggleTicket(ticketId: number): void {
+    if (collapsedTicketIds.has(ticketId)) {
+        collapsedTicketIds.delete(ticketId);
+    } else {
+        collapsedTicketIds.add(ticketId);
+    }
+}
+
+function toggleAllBranches(): void {
+    if (allVisibleBranchesCollapsed.value) {
+        collapsedTicketIds.clear();
+
+        return;
+    }
+
+    for (const ticketId of expandableTicketIds.value) {
+        collapsedTicketIds.add(ticketId);
+    }
+}
+
+function finishMove(ticketId: number): void {
+    if (pendingTicketId.value === ticketId) {
+        pendingTicketId.value = null;
+    }
+}
+
+watch(
+    () => props.project.id,
+    () => {
+        clearFilters();
+        collapsedTicketIds.clear();
+        pendingTicketId.value = null;
+    },
+);
 </script>
 
 <template>
     <AppLayout :breadcrumbs="breadcrumbs">
-        <Head :title="`${project.name} backlog`" />
+        <Head :title="t('backlog.title', { name: project.name })" />
 
-        <div class="flex flex-1 flex-col gap-6 p-4">
-            <div
-                class="flex flex-col gap-4 sm:flex-row sm:items-start sm:justify-between"
+        <div class="gap-page md:p-page flex min-w-0 flex-1 flex-col p-4">
+            <header
+                class="flex min-w-0 flex-col gap-4 xl:flex-row xl:items-start xl:justify-between"
             >
-                <div class="space-y-3">
-                    <Badge variant="outline" class="px-3 py-1">
-                        {{ project.key }}
-                    </Badge>
-                    <Heading
-                        :title="`${project.name} backlog`"
-                        description="All newly created tickets start here before they move onto the board."
-                    />
+                <div class="grid min-w-0 gap-2">
+                    <div class="flex min-w-0 flex-wrap items-center gap-3">
+                        <Badge
+                            variant="outline"
+                            class="wrap-anywhere max-w-full whitespace-normal"
+                        >
+                            {{ project.key }}
+                        </Badge>
+                        <p class="text-caption text-muted-foreground">
+                            {{ t('tickets.count', { count: tickets.length }) }}
+                        </p>
+                    </div>
+                    <h1
+                        class="text-headline-mobile md:text-headline wrap-anywhere"
+                    >
+                        {{ t('backlog.title', { name: project.name }) }}
+                    </h1>
+                    <p class="text-caption text-muted-foreground max-w-2xl">
+                        {{ t('backlog.description') }}
+                    </p>
                 </div>
 
-                <div class="flex flex-wrap gap-3">
+                <div class="flex flex-wrap gap-2">
                     <Button v-if="canCreateTickets" as-child>
                         <Link
                             :href="
@@ -74,138 +159,286 @@ const allowedTargetStatuses = (ticket: TicketModel): TicketStatusModel[] => {
                                 )
                             "
                         >
-                            Create ticket
+                            <Plus aria-hidden="true" />
+                            {{ t('navigation.createTicket') }}
                         </Link>
                     </Button>
-
                     <Button as-child variant="outline">
-                        <Link :href="boardIndex(project.id)">Open board</Link>
+                        <Link :href="boardIndex(project.id)">
+                            <Columns3 aria-hidden="true" />
+                            {{ t('backlog.openBoard') }}
+                        </Link>
                     </Button>
-
-                    <Button as-child variant="outline">
-                        <Link :href="show(project.id)">Back to project</Link>
+                    <Button as-child variant="ghost">
+                        <Link :href="show(project.id)">
+                            <ArrowLeft aria-hidden="true" />
+                            {{ t('backlog.backToProject') }}
+                        </Link>
                     </Button>
                 </div>
+            </header>
+
+            <FeedbackState v-if="status" state="success" :title="status" />
+
+            <section
+                aria-labelledby="backlog-filter-title"
+                class="bg-card gap-card p-card grid min-w-0 rounded-md border"
+            >
+                <div
+                    class="flex min-w-0 flex-col gap-3 sm:flex-row sm:items-start sm:justify-between"
+                >
+                    <div class="grid min-w-0 gap-1">
+                        <h2 id="backlog-filter-title" class="text-title">
+                            {{ t('backlog.filters.title') }}
+                        </h2>
+                        <p class="text-caption text-muted-foreground">
+                            {{ t('backlog.filters.description') }}
+                        </p>
+                    </div>
+                    <Button
+                        type="button"
+                        variant="ghost"
+                        size="sm"
+                        :disabled="!hasActiveFilters"
+                        @click="clearFilters"
+                    >
+                        <RotateCcw aria-hidden="true" />
+                        {{ t('backlog.filters.clear') }}
+                    </Button>
+                </div>
+
+                <div
+                    class="grid min-w-0 gap-3 sm:grid-cols-2 xl:grid-cols-[minmax(14rem,2fr)_repeat(4,minmax(9rem,1fr))]"
+                >
+                    <div
+                        class="grid min-w-0 gap-1.5 sm:col-span-2 xl:col-span-1"
+                    >
+                        <label
+                            for="backlog-query"
+                            class="text-caption font-semibold"
+                        >
+                            {{ t('backlog.filters.search') }}
+                        </label>
+                        <div class="relative min-w-0">
+                            <Search
+                                class="text-muted-foreground pointer-events-none absolute left-3 top-1/2 size-4 -translate-y-1/2"
+                                aria-hidden="true"
+                            />
+                            <input
+                                id="backlog-query"
+                                v-model="filters.query"
+                                type="search"
+                                class="border-input bg-card text-body min-h-control focus-visible:ring-ring/35 w-full min-w-0 rounded-md border py-2 pl-9 pr-3 focus-visible:outline-none focus-visible:ring-2"
+                                :placeholder="
+                                    t('backlog.filters.searchPlaceholder')
+                                "
+                            />
+                        </div>
+                    </div>
+
+                    <div class="grid min-w-0 gap-1.5">
+                        <label
+                            for="backlog-type"
+                            class="text-caption font-semibold"
+                        >
+                            {{ t('backlog.filters.type') }}
+                        </label>
+                        <select
+                            id="backlog-type"
+                            v-model="filters.typeId"
+                            class="border-input bg-card text-body min-h-control focus-visible:ring-ring/35 w-full min-w-0 rounded-md border px-3 py-2 focus-visible:outline-none focus-visible:ring-2"
+                        >
+                            <option value="">
+                                {{ t('backlog.filters.allTypes') }}
+                            </option>
+                            <option
+                                v-for="ticketType in ticketTypes"
+                                :key="ticketType.id"
+                                :value="ticketType.id"
+                            >
+                                {{ ticketType.name }}
+                            </option>
+                        </select>
+                    </div>
+
+                    <div class="grid min-w-0 gap-1.5">
+                        <label
+                            for="backlog-priority"
+                            class="text-caption font-semibold"
+                        >
+                            {{ t('backlog.filters.priority') }}
+                        </label>
+                        <select
+                            id="backlog-priority"
+                            v-model="filters.priorityId"
+                            class="border-input bg-card text-body min-h-control focus-visible:ring-ring/35 w-full min-w-0 rounded-md border px-3 py-2 focus-visible:outline-none focus-visible:ring-2"
+                        >
+                            <option value="">
+                                {{ t('backlog.filters.allPriorities') }}
+                            </option>
+                            <option
+                                v-for="priority in ticketPriorities"
+                                :key="priority.id"
+                                :value="priority.id"
+                            >
+                                {{ priority.name }}
+                            </option>
+                        </select>
+                    </div>
+
+                    <div class="grid min-w-0 gap-1.5">
+                        <label
+                            for="backlog-status"
+                            class="text-caption font-semibold"
+                        >
+                            {{ t('backlog.filters.status') }}
+                        </label>
+                        <select
+                            id="backlog-status"
+                            v-model="filters.statusId"
+                            class="border-input bg-card text-body min-h-control focus-visible:ring-ring/35 w-full min-w-0 rounded-md border px-3 py-2 focus-visible:outline-none focus-visible:ring-2"
+                        >
+                            <option value="">
+                                {{ t('backlog.filters.allStatuses') }}
+                            </option>
+                            <option
+                                v-for="ticketStatus in backlogTicketStatuses"
+                                :key="ticketStatus.id"
+                                :value="ticketStatus.id"
+                            >
+                                {{ ticketStatus.name }}
+                            </option>
+                        </select>
+                    </div>
+
+                    <div class="grid min-w-0 gap-1.5">
+                        <label
+                            for="backlog-assignee"
+                            class="text-caption font-semibold"
+                        >
+                            {{ t('backlog.filters.assignee') }}
+                        </label>
+                        <select
+                            id="backlog-assignee"
+                            v-model="filters.assigneeId"
+                            class="border-input bg-card text-body min-h-control focus-visible:ring-ring/35 w-full min-w-0 rounded-md border px-3 py-2 focus-visible:outline-none focus-visible:ring-2"
+                        >
+                            <option value="">
+                                {{ t('backlog.filters.allAssignees') }}
+                            </option>
+                            <option value="unassigned">
+                                {{ t('tickets.unassigned') }}
+                            </option>
+                            <option
+                                v-for="user in users"
+                                :key="user.id"
+                                :value="user.id"
+                            >
+                                {{ user.name }}
+                            </option>
+                        </select>
+                    </div>
+                </div>
+            </section>
+
+            <div
+                v-if="tickets.length === 0"
+                class="grid justify-items-start gap-3"
+            >
+                <FeedbackState
+                    state="empty"
+                    :title="t('backlog.empty.title')"
+                    :description="t('backlog.empty.description')"
+                />
+                <Button v-if="canCreateTickets" as-child size="sm">
+                    <Link
+                        :href="
+                            createTicket(
+                                { project: project.id },
+                                { query: { source: 'backlog' } },
+                            )
+                        "
+                    >
+                        <Plus aria-hidden="true" />
+                        {{ t('backlog.empty.action') }}
+                    </Link>
+                </Button>
             </div>
 
             <div
-                v-if="status"
-                class="rounded-xl border border-emerald-200 bg-emerald-50 px-4 py-3 text-sm text-emerald-900 dark:border-emerald-900/70 dark:bg-emerald-950/40 dark:text-emerald-100"
+                v-else-if="visibleTicketCount === 0"
+                class="grid justify-items-start gap-3"
             >
-                {{ status }}
+                <FeedbackState
+                    state="empty"
+                    :title="t('backlog.filters.empty.title')"
+                    :description="t('backlog.filters.empty.description')"
+                />
+                <Button
+                    type="button"
+                    variant="outline"
+                    size="sm"
+                    @click="clearFilters"
+                >
+                    <RotateCcw aria-hidden="true" />
+                    {{ t('backlog.filters.clear') }}
+                </Button>
             </div>
 
-            <Card class="gap-0 overflow-hidden">
-                <CardHeader class="border-b">
-                    <CardTitle>Backlog tickets</CardTitle>
-                    <CardDescription>
-                        Tickets remain here while their status belongs to
-                        backlog.
-                    </CardDescription>
-                </CardHeader>
-
-                <CardContent class="p-0">
-                    <div
-                        v-if="tickets.length === 0"
-                        class="text-muted-foreground p-6 text-sm"
-                    >
-                        No backlog tickets exist yet.
+            <section
+                v-else
+                aria-labelledby="backlog-results-title"
+                class="grid min-w-0 gap-3"
+            >
+                <div
+                    class="flex min-w-0 flex-col gap-3 sm:flex-row sm:items-center sm:justify-between"
+                >
+                    <div class="grid min-w-0 gap-1">
+                        <h2 id="backlog-results-title" class="text-title">
+                            {{ t('backlog.results.title') }}
+                        </h2>
+                        <p class="text-caption text-muted-foreground">
+                            {{
+                                t('backlog.results.count', {
+                                    count: visibleTicketCount,
+                                    total: tickets.length,
+                                })
+                            }}
+                        </p>
                     </div>
+                    <Button
+                        v-if="expandableTicketIds.length > 0"
+                        type="button"
+                        variant="outline"
+                        size="sm"
+                        @click="toggleAllBranches"
+                    >
+                        <ChevronsUpDown
+                            v-if="allVisibleBranchesCollapsed"
+                            aria-hidden="true"
+                        />
+                        <ChevronsDownUp v-else aria-hidden="true" />
+                        {{
+                            t(
+                                allVisibleBranchesCollapsed
+                                    ? 'backlog.tree.expandAll'
+                                    : 'backlog.tree.collapseAll',
+                            )
+                        }}
+                    </Button>
+                </div>
 
-                    <ul v-else class="gap-column grid p-4">
-                        <TicketListItem
-                            v-for="ticket in tickets"
-                            :key="ticket.id"
-                            :project-id="project.id"
-                            :ticket="ticket"
-                        >
-                            <template v-if="canEditTickets" #actions>
-                                <Form
-                                    v-bind="
-                                        ProjectBoardController.move.form({
-                                            project: project.id,
-                                            ticket: ticket.id,
-                                        })
-                                    "
-                                    class="flex w-full flex-col gap-2"
-                                    v-slot="{ processing }"
-                                >
-                                    <input
-                                        type="hidden"
-                                        name="redirect_to"
-                                        value="backlog"
-                                    />
-                                    <label
-                                        :for="`backlog-ticket-status-${ticket.id}`"
-                                        class="text-label text-muted-foreground uppercase"
-                                    >
-                                        Move to status
-                                    </label>
-                                    <div
-                                        class="flex flex-col gap-2 sm:flex-row"
-                                    >
-                                        <select
-                                            :id="`backlog-ticket-status-${ticket.id}`"
-                                            name="ticket_status_id"
-                                            :disabled="
-                                                allowedTargetStatuses(ticket)
-                                                    .length === 0 || processing
-                                            "
-                                            class="border-input bg-background shadow-xs focus-visible:border-ring focus-visible:ring-ring/50 min-h-control min-w-0 flex-1 rounded-md border px-3 py-2 text-sm outline-none transition-[color,box-shadow] focus-visible:ring-[3px] disabled:cursor-not-allowed disabled:opacity-60"
-                                        >
-                                            <option
-                                                v-if="
-                                                    allowedTargetStatuses(
-                                                        ticket,
-                                                    ).length === 0
-                                                "
-                                                value=""
-                                            >
-                                                No allowed moves
-                                            </option>
-                                            <option
-                                                v-for="ticketStatus in allowedTargetStatuses(
-                                                    ticket,
-                                                )"
-                                                :key="ticketStatus.id"
-                                                :value="ticketStatus.id"
-                                            >
-                                                {{
-                                                    ticketStatusLabel(
-                                                        ticketStatus,
-                                                        'Unknown status',
-                                                    )
-                                                }}
-                                            </option>
-                                        </select>
-                                        <Button
-                                            type="submit"
-                                            size="sm"
-                                            :disabled="
-                                                processing ||
-                                                allowedTargetStatuses(ticket)
-                                                    .length === 0
-                                            "
-                                        >
-                                            Move
-                                        </Button>
-                                    </div>
-                                    <p
-                                        v-if="
-                                            allowedTargetStatuses(ticket)
-                                                .length === 0
-                                        "
-                                        class="text-caption text-muted-foreground"
-                                    >
-                                        This status does not allow moving
-                                        anywhere else.
-                                    </p>
-                                </Form>
-                            </template>
-                        </TicketListItem>
-                    </ul>
-                </CardContent>
-            </Card>
+                <BacklogTicketTree
+                    :nodes="filteredTicketTree"
+                    :project-id="project.id"
+                    :can-edit-tickets="canEditTickets"
+                    :collapsed-ticket-ids="collapsedTicketIds"
+                    :pending-ticket-id="pendingTicketId"
+                    @toggle="toggleTicket"
+                    @move-start="pendingTicketId = $event"
+                    @move-finish="finishMove"
+                />
+            </section>
         </div>
     </AppLayout>
 </template>
diff --git a/resources/js/types/backlog.ts b/resources/js/types/backlog.ts
new file mode 100644
index 0000000..62a5e79
--- /dev/null
+++ b/resources/js/types/backlog.ts
@@ -0,0 +1,31 @@
+import type { TicketModel } from '@/types/models/ticket-model';
+
+export type BacklogAssigneeFilter = '' | 'unassigned' | number;
+
+export type BacklogFilterState = {
+    assigneeId: BacklogAssigneeFilter;
+    priorityId: '' | number;
+    query: string;
+    statusId: '' | number;
+    typeId: '' | number;
+};
+
+export type BacklogTicketTreeNode = {
+    children: BacklogTicketTreeNode[];
+    matchesFilters: boolean;
+    ticket: TicketModel;
+};
+
+export type BacklogTicketTreeProps = {
+    canEditTickets: boolean;
+    collapsedTicketIds: Set<number>;
+    nodes: BacklogTicketTreeNode[];
+    pendingTicketId: number | null;
+    projectId: number;
+};
+
+export type BacklogTicketTreeEmits = {
+    moveFinish: [ticketId: number];
+    moveStart: [ticketId: number];
+    toggle: [ticketId: number];
+};
diff --git a/resources/js/types/index.ts b/resources/js/types/index.ts
index 0d3c79c..4d7a809 100644
--- a/resources/js/types/index.ts
+++ b/resources/js/types/index.ts
@@ -1,4 +1,6 @@
 export * from './auth';
+export * from './backlog';
 export * from './navigation';
 export * from './page-props';
+export * from './ticket-tree';
 export * from './ui';
diff --git a/resources/js/types/ticket-presentation.ts b/resources/js/types/ticket-presentation.ts
index 6c4cfa1..370de4f 100644
--- a/resources/js/types/ticket-presentation.ts
+++ b/resources/js/types/ticket-presentation.ts
@@ -1,6 +1,7 @@
 import type { TicketModel } from '@/types/models/ticket-model';
 
 export type TicketPresentationProps = {
+    layout?: 'card' | 'list';
     projectId: number;
     showDescription?: boolean;
     showStatus?: boolean;
diff --git a/resources/js/types/ticket-tree.ts b/resources/js/types/ticket-tree.ts
new file mode 100644
index 0000000..efdfe85
--- /dev/null
+++ b/resources/js/types/ticket-tree.ts
@@ -0,0 +1,6 @@
+import type { TicketTreeNodeModel } from '@/types/models/ticket-tree-node-model';
+
+export type TicketTreeListProps = {
+    nodes: TicketTreeNodeModel[];
+    projectId: number;
+};
diff --git a/tests/Feature/Projects/ProjectBacklogTest.php b/tests/Feature/Projects/ProjectBacklogTest.php
index f6551ea..166f20c 100644
--- a/tests/Feature/Projects/ProjectBacklogTest.php
+++ b/tests/Feature/Projects/ProjectBacklogTest.php
@@ -71,6 +71,110 @@ class ProjectBacklogTest extends TestCase
             );
     }
 
+    /**
+     * Ensure the backlog payload supports nested tickets and their allowed status moves.
+     */
+    public function test_backlog_includes_nested_tickets_and_allowed_status_moves(): void
+    {
+        $editor = User::factory()->create();
+        $project = Project::factory()->create([
+            'key' => 'TREE',
+        ]);
+
+        app(InitializeProjectTicketMetadata::class)->handle($project);
+
+        $backlogStatus = $project->ticketStatuses()
+            ->whereNull('board_column_id')
+            ->firstOrFail();
+        $boardColumn = BoardColumn::factory()->for($project)->create([
+            'name' => 'Todo',
+            'position' => 1,
+        ]);
+        $boardStatus = TicketStatus::factory()
+            ->for($project)
+            ->for($boardColumn)
+            ->create([
+                'name' => 'Ready',
+                'position' => 1,
+            ]);
+        $backlogStatus->allowedTargetStatuses()->sync([$boardStatus->id]);
+
+        $parentType = $project->ticketTypes()
+            ->where('is_parent', true)
+            ->firstOrFail();
+        $taskType = $project->ticketTypes()
+            ->where('is_parent', false)
+            ->firstOrFail();
+        $priority = $project->ticketPriorities()->firstOrFail();
+
+        $parentTicket = Ticket::factory()->create([
+            'project_id' => $project->id,
+            'sequence_number' => 1,
+            'ticket_key' => 'TREE-1',
+            'ticket_priority_id' => $priority->id,
+            'ticket_status_id' => $backlogStatus->id,
+            'ticket_type_id' => $parentType->id,
+            'title' => 'Parent ticket',
+        ]);
+        $childTicket = Ticket::factory()->create([
+            'parent_ticket_id' => $parentTicket->id,
+            'project_id' => $project->id,
+            'sequence_number' => 2,
+            'ticket_key' => 'TREE-2',
+            'ticket_priority_id' => $priority->id,
+            'ticket_status_id' => $backlogStatus->id,
+            'ticket_type_id' => $taskType->id,
+            'title' => 'Child ticket',
+        ]);
+
+        $this->syncProjectPermissions($project, $editor, ['edit', 'view']);
+
+        $this->actingAs($editor)
+            ->get(route('projects.backlog.index', $project))
+            ->assertOk()
+            ->assertInertia(fn (Assert $page) => $page
+                ->component('projects/Backlog')
+                ->where('canEditTickets', true)
+                ->has('tickets', 2)
+                ->where('tickets.0.id', $childTicket->id)
+                ->where('tickets.0.parent_ticket_id', $parentTicket->id)
+                ->where('tickets.0.ticket_status.allowed_target_statuses.0.id', $boardStatus->id)
+                ->where('tickets.1.id', $parentTicket->id)
+                ->where('tickets.1.parent_ticket_id', null)
+                ->where('tickets.1.ticket_status.allowed_target_statuses.0.id', $boardStatus->id),
+            );
+
+        $this->assertDatabaseHas('tickets', [
+            'id' => $parentTicket->id,
+            'ticket_status_id' => $backlogStatus->id,
+        ]);
+        $this->assertDatabaseHas('tickets', [
+            'id' => $childTicket->id,
+            'parent_ticket_id' => $parentTicket->id,
+            'ticket_status_id' => $backlogStatus->id,
+        ]);
+    }
+
+    /**
+     * Ensure projects without backlog tickets receive an empty collection.
+     */
+    public function test_projects_without_backlog_tickets_receive_an_empty_collection(): void
+    {
+        $viewer = User::factory()->create();
+        $project = Project::factory()->create();
+
+        app(InitializeProjectTicketMetadata::class)->handle($project);
+        $this->syncProjectPermissions($project, $viewer, ['view']);
+
+        $this->actingAs($viewer)
+            ->get(route('projects.backlog.index', $project))
+            ->assertOk()
+            ->assertInertia(fn (Assert $page) => $page
+                ->component('projects/Backlog')
+                ->where('tickets', []),
+            );
+    }
+
     /**
      * Ensure creating tickets requires the project write permission.
      */