From 883393788b1b32e694c4f8712928c910936dc6b4 Mon Sep 17 00:00:00 2001
From: Sergei Ogorelkov <sergei.ogorelkov@xored.com>
Date: Thu, 2 Jun 2022 09:42:44 +0700
Subject: [PATCH] Tracker: change "Issue" type to "AttachedDoc" (#1875)

Signed-off-by: Sergei Ogorelkov <sergei.ogorelkov@xored.com>
---
 models/tracker/src/index.ts                   |   8 +-
 models/tracker/src/migration.ts               |  53 ++++++++-
 .../src/components/CreateIssue.svelte         |  35 +++---
 .../components/SetDueDateActionPopup.svelte   |  10 +-
 .../SetParentIssueActionPopup.svelte          |  14 ++-
 .../components/issues/AssigneeEditor.svelte   |  10 +-
 .../issues/AssigneePresenter.svelte           |  10 +-
 .../components/issues/DueDateEditor.svelte    |  10 +-
 .../components/issues/DueDatePresenter.svelte |  10 +-
 .../components/issues/PriorityEditor.svelte   |  10 +-
 .../src/components/issues/StatusEditor.svelte |  10 +-
 .../components/issues/edit/EditIssue.svelte   |  20 +++-
 .../issues/edit/SubIssueSelector.svelte       | 106 ++++++++++++------
 .../components/projects/ProjectEditor.svelte  |  10 +-
 plugins/tracker-resources/src/plugin.ts       |   2 +-
 plugins/tracker/src/index.ts                  |   7 +-
 server/core/src/storage.ts                    | 106 ++++++++++++++----
 17 files changed, 334 insertions(+), 97 deletions(-)

diff --git a/models/tracker/src/index.ts b/models/tracker/src/index.ts
index d13d4279ef..57542cdaa8 100644
--- a/models/tracker/src/index.ts
+++ b/models/tracker/src/index.ts
@@ -125,9 +125,9 @@ export class TTeam extends TSpace implements Team {
 /**
  * @public
  */
-@Model(tracker.class.Issue, core.class.Doc, DOMAIN_TRACKER)
+@Model(tracker.class.Issue, core.class.AttachedDoc, DOMAIN_TRACKER)
 @UX(tracker.string.Issue, tracker.icon.Issue, tracker.string.Issue)
-export class TIssue extends TDoc implements Issue {
+export class TIssue extends TAttachedDoc implements Issue {
   @Prop(TypeString(), tracker.string.Title)
   @Index(IndexKind.FullText)
   title!: string
@@ -151,8 +151,8 @@ export class TIssue extends TDoc implements Issue {
   @Prop(TypeRef(tracker.class.Project), tracker.string.Project)
   project!: Ref<Project> | null
 
-  @Prop(TypeRef(tracker.class.Issue), tracker.string.Parent)
-  parentIssue!: Ref<Issue>
+  @Prop(Collection(tracker.class.Issue), tracker.string.SubIssues)
+  subIssues!: number
 
   @Prop(ArrOf(TypeRef(tracker.class.Issue)), tracker.string.BlockedBy)
   blockedBy!: Ref<Issue>[]
diff --git a/models/tracker/src/migration.ts b/models/tracker/src/migration.ts
index 4744cf2d93..a0887f0d31 100644
--- a/models/tracker/src/migration.ts
+++ b/models/tracker/src/migration.ts
@@ -13,9 +13,9 @@
 // limitations under the License.
 //
 
-import core, { generateId, Ref, TxOperations } from '@anticrm/core'
+import core, { Doc, generateId, Ref, TxOperations } from '@anticrm/core'
 import { MigrateOperation, MigrationClient, MigrationUpgradeClient } from '@anticrm/model'
-import { IssueStatus, IssueStatusCategory, Team, genRanks } from '@anticrm/tracker'
+import { IssueStatus, IssueStatusCategory, Team, genRanks, Issue } from '@anticrm/tracker'
 import { DOMAIN_TRACKER } from '.'
 import tracker from './plugin'
 
@@ -149,6 +149,53 @@ async function upgradeIssueStatuses (tx: TxOperations): Promise<void> {
   }
 }
 
+async function migrateParentIssues (client: MigrationClient): Promise<void> {
+  let { updated } = await client.update(
+    DOMAIN_TRACKER,
+    { _class: tracker.class.Issue, attachedToClass: { $exists: false } },
+    {
+      subIssues: 0,
+      collection: 'subIssues',
+      attachedToClass: tracker.class.Issue
+    }
+  )
+  updated += (
+    await client.update(
+      DOMAIN_TRACKER,
+      { _class: tracker.class.Issue, parentIssue: { $exists: true } },
+      { $rename: { parentIssue: 'attachedTo' } }
+    )
+  ).updated
+  updated += (
+    await client.update(
+      DOMAIN_TRACKER,
+      { _class: tracker.class.Issue, attachedTo: { $in: [null, undefined] } },
+      { attachedTo: tracker.ids.NoParent }
+    )
+  ).updated
+
+  if (updated === 0) {
+    return
+  }
+
+  const childrenCountById = new Map<Ref<Doc>, number>()
+  const parentIssueIds = (
+    await client.find<Issue>(DOMAIN_TRACKER, {
+      _class: tracker.class.Issue,
+      attachedTo: { $nin: [tracker.ids.NoParent] }
+    })
+  ).map((issue) => issue.attachedTo)
+
+  for (const issueId of parentIssueIds) {
+    const count = childrenCountById.get(issueId) ?? 0
+    childrenCountById.set(issueId, count + 1)
+  }
+
+  for (const [_id, childrenCount] of childrenCountById) {
+    await client.update(DOMAIN_TRACKER, { _id }, { subIssues: childrenCount })
+  }
+}
+
 async function migrateIssueProjects (client: MigrationClient): Promise<void> {
   const issues = await client.find(DOMAIN_TRACKER, { _class: tracker.class.Issue, project: { $exists: false } })
 
@@ -197,7 +244,7 @@ async function upgradeProjects (tx: TxOperations): Promise<void> {
 
 export const trackerOperation: MigrateOperation = {
   async migrate (client: MigrationClient): Promise<void> {
-    await Promise.all([migrateIssueProjects(client)])
+    await Promise.all([migrateIssueProjects(client), migrateParentIssues(client)])
   },
   async upgrade (client: MigrationUpgradeClient): Promise<void> {
     const tx = new TxOperations(client, core.account.System)
diff --git a/plugins/tracker-resources/src/components/CreateIssue.svelte b/plugins/tracker-resources/src/components/CreateIssue.svelte
index 649612875e..78280eb0c8 100644
--- a/plugins/tracker-resources/src/components/CreateIssue.svelte
+++ b/plugins/tracker-resources/src/components/CreateIssue.svelte
@@ -14,7 +14,7 @@
 -->
 <script lang="ts">
   import contact, { Employee } from '@anticrm/contact'
-  import core, { Data, generateId, Ref, SortingOrder, WithLookup } from '@anticrm/core'
+  import core, { AttachedData, Ref, SortingOrder, WithLookup } from '@anticrm/core'
   import presentation, { Card, createQuery, getClient, SpaceSelector, UserBox } from '@anticrm/presentation'
   import { StyledTextBox } from '@anticrm/text-editor'
   import { calcRank, Issue, IssuePriority, IssueStatus, Project, Team } from '@anticrm/tracker'
@@ -48,7 +48,7 @@
   let issueStatuses: WithLookup<IssueStatus>[] | undefined
   let parentIssue: Issue | undefined
 
-  let object: Data<Issue> = {
+  let object: AttachedData<Issue> = {
     title: '',
     description: '',
     assignee: null,
@@ -58,13 +58,13 @@
     status: '' as Ref<IssueStatus>,
     priority: priority,
     dueDate: null,
-    comments: 0
+    comments: 0,
+    subIssues: 0
   }
 
   const dispatch = createEventDispatcher()
   const client = getClient()
   const statusesQuery = createQuery()
-  const taskId: Ref<Issue> = generateId()
 
   $: _space = space
   $: updateIssueStatusId(space, status)
@@ -95,7 +95,6 @@
 
   function clearParentIssue () {
     parentIssue = undefined
-    object.parentIssue = undefined
   }
 
   function getTitle (value: string) {
@@ -126,7 +125,7 @@
       true
     )
 
-    const value: Data<Issue> = {
+    const value: AttachedData<Issue> = {
       title: getTitle(object.title),
       description: object.description,
       assignee: currentAssignee,
@@ -135,12 +134,19 @@
       status: object.status,
       priority: object.priority,
       rank: calcRank(lastOne, undefined),
-      parentIssue: object.parentIssue,
       comments: 0,
+      subIssues: 0,
       dueDate: object.dueDate
     }
 
-    await client.createDoc(tracker.class.Issue, _space, value, taskId)
+    await client.addCollection(
+      tracker.class.Issue,
+      _space,
+      parentIssue?._id ?? tracker.ids.NoParent,
+      parentIssue?._class ?? tracker.class.Issue,
+      'subIssues',
+      value
+    )
   }
 
   async function showMoreActions (ev: Event) {
@@ -160,23 +166,18 @@
     }
 
     const setParentIssue = {
-      label: object.parentIssue ? tracker.string.ChangeParent : tracker.string.SetParent,
+      label: parentIssue ? tracker.string.ChangeParent : tracker.string.SetParent,
       icon: tracker.icon.Parent,
       action: async () =>
         showPopup(
           SetParentIssueActionPopup,
-          { value: { ...object, space }, shouldSaveOnChange: false },
+          { value: { ...object, space, attachedTo: parentIssue?._id }, shouldSaveOnChange: false },
           'top',
-          (selectedIssue) => {
-            if (selectedIssue !== undefined) {
-              parentIssue = selectedIssue
-              object.parentIssue = parentIssue?._id
-            }
-          }
+          (selectedIssue) => selectedIssue !== undefined && (parentIssue = selectedIssue)
         )
     }
 
-    const removeParentIssue = object.parentIssue && {
+    const removeParentIssue = parentIssue && {
       label: tracker.string.RemoveParent,
       icon: tracker.icon.Parent,
       action: clearParentIssue
diff --git a/plugins/tracker-resources/src/components/SetDueDateActionPopup.svelte b/plugins/tracker-resources/src/components/SetDueDateActionPopup.svelte
index 6f6b3c4f09..798663b2b0 100644
--- a/plugins/tracker-resources/src/components/SetDueDateActionPopup.svelte
+++ b/plugins/tracker-resources/src/components/SetDueDateActionPopup.svelte
@@ -30,7 +30,15 @@
     const newDueDate = detail && detail?.getTime()
 
     if (shouldSaveOnChange && newDueDate !== undefined && newDueDate !== value.dueDate) {
-      await client.update(value, { dueDate: newDueDate })
+      await client.updateCollection(
+        value._class,
+        value.space,
+        value._id,
+        value.attachedTo,
+        value.attachedToClass,
+        value.collection,
+        { dueDate: newDueDate }
+      )
     }
 
     dispatch('update', newDueDate)
diff --git a/plugins/tracker-resources/src/components/SetParentIssueActionPopup.svelte b/plugins/tracker-resources/src/components/SetParentIssueActionPopup.svelte
index 172f9f5fd4..d7bce7e922 100644
--- a/plugins/tracker-resources/src/components/SetParentIssueActionPopup.svelte
+++ b/plugins/tracker-resources/src/components/SetParentIssueActionPopup.svelte
@@ -42,8 +42,16 @@
   }
 
   async function onClose ({ detail: parentIssue }: CustomEvent<Issue | undefined | null>) {
-    if (shouldSaveOnChange && parentIssue !== undefined && parentIssue?._id !== value.parentIssue) {
-      await client.update(value, { parentIssue: parentIssue?._id })
+    if (shouldSaveOnChange && parentIssue !== undefined && parentIssue?._id !== value.attachedTo) {
+      await client.updateCollection(
+        value._class,
+        value.space,
+        value._id,
+        value.attachedTo,
+        value.attachedToClass,
+        'subIssues',
+        { attachedTo: parentIssue === null ? tracker.ids.NoParent : parentIssue._id }
+      )
     }
 
     dispatch('close', parentIssue)
@@ -59,7 +67,7 @@
 <ObjectPopup
   _class={tracker.class.Issue}
   {options}
-  selected={value.parentIssue}
+  selected={value.attachedTo}
   multiSelect={false}
   allowDeselect={true}
   placeholder={tracker.string.SetParent}
diff --git a/plugins/tracker-resources/src/components/issues/AssigneeEditor.svelte b/plugins/tracker-resources/src/components/issues/AssigneeEditor.svelte
index dca78f50b3..776af7e55b 100644
--- a/plugins/tracker-resources/src/components/issues/AssigneeEditor.svelte
+++ b/plugins/tracker-resources/src/components/issues/AssigneeEditor.svelte
@@ -30,7 +30,15 @@
       return
     }
 
-    await client.update(value, { assignee: newAssignee })
+    await client.updateCollection(
+      value._class,
+      value.space,
+      value._id,
+      value.attachedTo,
+      value.attachedToClass,
+      value.collection,
+      { assignee: newAssignee }
+    )
   }
 </script>
 
diff --git a/plugins/tracker-resources/src/components/issues/AssigneePresenter.svelte b/plugins/tracker-resources/src/components/issues/AssigneePresenter.svelte
index c8b0b8c58f..bad9451977 100644
--- a/plugins/tracker-resources/src/components/issues/AssigneePresenter.svelte
+++ b/plugins/tracker-resources/src/components/issues/AssigneePresenter.svelte
@@ -60,7 +60,15 @@
 
     const newAssignee = result === null ? null : result._id
 
-    await client.update(currentIssue, { assignee: newAssignee })
+    await client.updateCollection(
+      currentIssue._class,
+      currentIssue.space,
+      currentIssue._id,
+      currentIssue.attachedTo,
+      currentIssue.attachedToClass,
+      currentIssue.collection,
+      { assignee: newAssignee }
+    )
   }
 
   const handleAssigneeEditorOpened = async (event: MouseEvent) => {
diff --git a/plugins/tracker-resources/src/components/issues/DueDateEditor.svelte b/plugins/tracker-resources/src/components/issues/DueDateEditor.svelte
index 39fed67fd6..98652adbc2 100644
--- a/plugins/tracker-resources/src/components/issues/DueDateEditor.svelte
+++ b/plugins/tracker-resources/src/components/issues/DueDateEditor.svelte
@@ -27,7 +27,15 @@
       return
     }
 
-    await client.update(value, { dueDate: newDueDate })
+    await client.updateCollection(
+      value._class,
+      value.space,
+      value._id,
+      value.attachedTo,
+      value.attachedToClass,
+      value.collection,
+      { dueDate: newDueDate }
+    )
   }
 
   $: today = new Date(new Date(Date.now()).setHours(0, 0, 0, 0))
diff --git a/plugins/tracker-resources/src/components/issues/DueDatePresenter.svelte b/plugins/tracker-resources/src/components/issues/DueDatePresenter.svelte
index 63b7386898..f6e5a6d4b7 100644
--- a/plugins/tracker-resources/src/components/issues/DueDatePresenter.svelte
+++ b/plugins/tracker-resources/src/components/issues/DueDatePresenter.svelte
@@ -26,7 +26,15 @@
   $: dueDateMs = value.dueDate
 
   const handleDueDateChanged = async (newDate: number | null) => {
-    await client.update(value, { dueDate: newDate })
+    await client.updateCollection(
+      value._class,
+      value.space,
+      value._id,
+      value.attachedTo,
+      value.attachedToClass,
+      value.collection,
+      { dueDate: newDate }
+    )
   }
 
   $: shouldRenderPresenter =
diff --git a/plugins/tracker-resources/src/components/issues/PriorityEditor.svelte b/plugins/tracker-resources/src/components/issues/PriorityEditor.svelte
index 361c648e6a..d18812c1a9 100644
--- a/plugins/tracker-resources/src/components/issues/PriorityEditor.svelte
+++ b/plugins/tracker-resources/src/components/issues/PriorityEditor.svelte
@@ -36,7 +36,15 @@
       return
     }
 
-    await client.update(value, { priority: newPriority })
+    await client.updateCollection(
+      value._class,
+      value.space,
+      value._id,
+      value.attachedTo,
+      value.attachedToClass,
+      value.collection,
+      { priority: newPriority }
+    )
   }
 </script>
 
diff --git a/plugins/tracker-resources/src/components/issues/StatusEditor.svelte b/plugins/tracker-resources/src/components/issues/StatusEditor.svelte
index dc0ffc0f27..e550c71f6d 100644
--- a/plugins/tracker-resources/src/components/issues/StatusEditor.svelte
+++ b/plugins/tracker-resources/src/components/issues/StatusEditor.svelte
@@ -38,7 +38,15 @@
       return
     }
 
-    await client.update(value, { status: newStatus })
+    await client.updateCollection(
+      value._class,
+      value.space,
+      value._id,
+      value.attachedTo,
+      value.attachedToClass,
+      value.collection,
+      { status: newStatus }
+    )
   }
 </script>
 
diff --git a/plugins/tracker-resources/src/components/issues/edit/EditIssue.svelte b/plugins/tracker-resources/src/components/issues/edit/EditIssue.svelte
index 57b2f4f345..5c09ab0c25 100644
--- a/plugins/tracker-resources/src/components/issues/edit/EditIssue.svelte
+++ b/plugins/tracker-resources/src/components/issues/edit/EditIssue.svelte
@@ -47,7 +47,7 @@
   const dispatch = createEventDispatcher()
   const client = getClient()
 
-  let issue: Issue | undefined
+  let issue: WithLookup<Issue> | undefined
   let currentTeam: Team | undefined
   let issueStatuses: WithLookup<IssueStatus>[] | undefined
   let title = ''
@@ -65,7 +65,7 @@
         title = issue.title
         description = issue.description
       },
-      { lookup: { parentIssue: _class } }
+      { lookup: { attachedTo: tracker.class.Issue } }
     )
 
   $: if (issue) {
@@ -123,7 +123,15 @@
     }
 
     if (Object.keys(updates).length > 0) {
-      await client.update(issue, updates)
+      await client.updateCollection(
+        issue._class,
+        issue.space,
+        issue._id,
+        issue.attachedTo,
+        issue.attachedToClass,
+        issue.collection,
+        updates
+      )
     }
 
     isEditing = false
@@ -152,6 +160,7 @@
     on:fullsize
     on:close={() => dispatch('close')}
   >
+    {@const { attachedTo: parentIssue } = issue?.$lookup ?? {}}
     <svelte:fragment slot="subtitle">
       <div class="flex-between flex-grow">
         <div class="buttons-group xsmall-gap">
@@ -184,7 +193,7 @@
     {#if isEditing}
       <Scroller>
         <div class="popupPanel-body__main-content py-10 clear-mins content">
-          {#if issue?.parentIssue}
+          {#if parentIssue}
             <div class="mb-6">
               {#if currentTeam && issueStatuses}
                 <SubIssueSelector {issue} {issueStatuses} team={currentTeam} />
@@ -211,7 +220,7 @@
         </div>
       </Scroller>
     {:else}
-      {#if issue?.parentIssue}
+      {#if parentIssue}
         <div class="mb-6">
           {#if currentTeam && issueStatuses}
             <SubIssueSelector {issue} {issueStatuses} team={currentTeam} />
@@ -261,6 +270,7 @@
 
   .description-preview {
     color: var(--theme-content-color);
+    line-height: 150%;
 
     .placeholder {
       color: var(--theme-content-trans-color);
diff --git a/plugins/tracker-resources/src/components/issues/edit/SubIssueSelector.svelte b/plugins/tracker-resources/src/components/issues/edit/SubIssueSelector.svelte
index 8333198f40..377a312a80 100644
--- a/plugins/tracker-resources/src/components/issues/edit/SubIssueSelector.svelte
+++ b/plugins/tracker-resources/src/components/issues/edit/SubIssueSelector.svelte
@@ -16,7 +16,17 @@
   import { Ref, SortingOrder, WithLookup } from '@anticrm/core'
   import { createQuery } from '@anticrm/presentation'
   import { Team, Issue, IssueStatus } from '@anticrm/tracker'
-  import { Icon, Tooltip, showPanel, IconForward, IconDetails, showPopup, SelectPopup, closeTooltip } from '@anticrm/ui'
+  import {
+    Icon,
+    Tooltip,
+    showPanel,
+    IconForward,
+    IconDetails,
+    showPopup,
+    SelectPopup,
+    closeTooltip,
+    Spinner
+  } from '@anticrm/ui'
   import tracker from '../../../plugin'
 
   export let issue: WithLookup<Issue>
@@ -43,9 +53,9 @@
   }
 
   function openParentIssue () {
-    if (issue.parentIssue) {
+    if (parentIssue) {
       closeTooltip()
-      openIssue(issue.parentIssue)
+      openIssue(parentIssue._id)
     }
   }
 
@@ -77,21 +87,23 @@
     }
   }
 
-  $: subIssuesQeury.query(
-    tracker.class.Issue,
-    { space: issue.space, parentIssue: issue.parentIssue },
-    (res) => (subIssues = res),
-    { sort: { modifiedOn: SortingOrder.Descending } }
-  )
-  $: parentIssue = issue.$lookup?.parentIssue ?? null
+  $: areSubIssuesLoading = !subIssues
+  $: parentIssue = issue.$lookup?.attachedTo ? (issue.$lookup?.attachedTo as Issue) : null
+  $: parentIssue &&
+    subIssuesQeury.query(
+      tracker.class.Issue,
+      { space: issue.space, attachedTo: parentIssue._id },
+      (res) => (subIssues = res),
+      { sort: { modifiedOn: SortingOrder.Descending } }
+    )
 </script>
 
-<div class="flex root">
-  <div class="clear-mins parent-issue item">
-    {#if parentIssue}
+{#if parentIssue}
+  <div class="flex root">
+    <div class="item clear-mins">
       <Tooltip label={tracker.string.OpenParent} direction="bottom" fill>
         {@const icon = getIssueStatusIcon(issue)}
-        <div class="flex-center" on:click={openParentIssue}>
+        <div class="flex-center parent-issue" on:click={openParentIssue}>
           {#if icon}
             <div class="pr-2">
               <Icon {icon} size="small" />
@@ -101,40 +113,65 @@
           <span class="overflow-label issue-title">{parentIssue.title}</span>
         </div>
       </Tooltip>
-    {/if}
-  </div>
-
-  <Tooltip label={tracker.string.OpenSub} direction="bottom">
-    <div bind:this={subIssuesElement} class="flex-center sub-issues item" on:click|preventDefault={showSubIssues}>
-      {#if subIssues?.length !== undefined}
-        <span class="overflow-label">{subIssues.length}</span>
-      {/if}
-      <div class="ml-2">
-        <!-- TODO: fix icon -->
-        <Icon icon={IconDetails} size="small" />
-      </div>
-      <div class="ml-1-5">
-        <Icon icon={IconForward} size="small" />
-      </div>
     </div>
-  </Tooltip>
-</div>
+
+    <div class="item">
+      {#if areSubIssuesLoading}
+        <div class="flex-center spinner">
+          <Spinner size="small" />
+        </div>
+      {:else}
+        <Tooltip label={tracker.string.OpenSub} direction="bottom">
+          <div
+            bind:this={subIssuesElement}
+            class="flex-center sub-issues"
+            on:click|preventDefault={areSubIssuesLoading ? undefined : showSubIssues}
+          >
+            <span class="overflow-label">{subIssues?.length}</span>
+            <div class="ml-2">
+              <!-- TODO: fix icon -->
+              <Icon icon={IconDetails} size="small" />
+            </div>
+            <div class="ml-1-5">
+              <Icon icon={IconForward} size="small" />
+            </div>
+          </div>
+        </Tooltip>
+      {/if}
+    </div>
+  </div>
+{/if}
 
 <style lang="scss">
+  $padding: 0.375rem 0.75rem;
+  $border: 1px solid var(--button-border-color);
+
   .root {
     max-width: fit-content;
     line-height: 150%;
-    border: 1px solid var(--button-border-color);
+    border: $border;
     border-radius: 0.25rem;
     box-shadow: var(--primary-shadow);
 
     .item {
-      padding: 0.375rem 0.75rem;
+      position: relative;
+
+      &:not(:first-child)::before {
+        position: absolute;
+        content: '';
+        border-left: $border;
+        inset: 0.375rem auto;
+      }
     }
   }
 
+  .spinner {
+    padding: $padding;
+    height: 100%;
+  }
+
   .parent-issue {
-    border-right: 1px solid var(--button-border-color);
+    padding: $padding;
 
     .issue-title {
       color: var(--theme-content-accent-color);
@@ -154,6 +191,7 @@
   }
 
   .sub-issues {
+    padding: $padding;
     color: var(--theme-content-color);
     transition: color 0.15s;
 
diff --git a/plugins/tracker-resources/src/components/projects/ProjectEditor.svelte b/plugins/tracker-resources/src/components/projects/ProjectEditor.svelte
index 57a42b9d34..46104f7433 100644
--- a/plugins/tracker-resources/src/components/projects/ProjectEditor.svelte
+++ b/plugins/tracker-resources/src/components/projects/ProjectEditor.svelte
@@ -39,7 +39,15 @@
       return
     }
 
-    await client.update(value, { project: newProjectId })
+    await client.updateCollection(
+      value._class,
+      value.space,
+      value._id,
+      value.attachedTo,
+      value.attachedToClass,
+      value.collection,
+      { project: newProjectId }
+    )
   }
 </script>
 
diff --git a/plugins/tracker-resources/src/plugin.ts b/plugins/tracker-resources/src/plugin.ts
index a8ceab2344..0e7fa43498 100644
--- a/plugins/tracker-resources/src/plugin.ts
+++ b/plugins/tracker-resources/src/plugin.ts
@@ -86,7 +86,7 @@ export default mergeIds(trackerId, tracker, {
     Assignee: '' as IntlString,
     AssignTo: '' as IntlString,
     AssignedTo: '' as IntlString,
-    Parent: '' as IntlString,
+    SubIssues: '' as IntlString,
     SetParent: '' as IntlString,
     ChangeParent: '' as IntlString,
     RemoveParent: '' as IntlString,
diff --git a/plugins/tracker/src/index.ts b/plugins/tracker/src/index.ts
index 3da950976d..b2c078a9a9 100644
--- a/plugins/tracker/src/index.ts
+++ b/plugins/tracker/src/index.ts
@@ -97,7 +97,7 @@ export enum IssuesDateModificationPeriod {
 /**
  * @public
  */
-export interface Issue extends Doc {
+export interface Issue extends AttachedDoc {
   title: string
   description: Markup
   status: Ref<IssueStatus>
@@ -108,7 +108,7 @@ export interface Issue extends Doc {
   project: Ref<Project> | null
 
   // For subtasks
-  parentIssue?: Ref<Issue>
+  subIssues: number
   blockedBy?: Ref<Issue>[]
   relatedIssue?: Ref<Issue>[]
 
@@ -189,6 +189,9 @@ export default plugin(trackerId, {
     IssueStatusCategory: '' as Ref<Class<IssueStatusCategory>>,
     TypeIssuePriority: '' as Ref<Class<Type<IssuePriority>>>
   },
+  ids: {
+    NoParent: '' as Ref<Issue>
+  },
   component: {
     Tracker: '' as AnyComponent,
     TrackerApp: '' as AnyComponent
diff --git a/server/core/src/storage.ts b/server/core/src/storage.ts
index b06ab1186e..e39f49396d 100644
--- a/server/core/src/storage.ts
+++ b/server/core/src/storage.ts
@@ -15,12 +15,14 @@
 //
 
 import core, {
+  Account,
   AttachedDoc,
   Class,
   ClassifierKind,
   Collection,
   Doc,
   DocumentQuery,
+  DocumentUpdate,
   Domain,
   DOMAIN_MODEL,
   DOMAIN_TX,
@@ -125,12 +127,82 @@ class TServerStorage implements ServerStorage {
     }
   }
 
+  private async getCollectionUpdateTx<D extends Doc>(
+    _id: Ref<D>,
+    _class: Ref<Class<D>>,
+    modifiedBy: Ref<Account>,
+    modifiedOn: number,
+    attachedTo: D,
+    update: DocumentUpdate<D>
+  ): Promise<Tx> {
+    const txFactory = new TxFactory(modifiedBy)
+    const baseClass = this.hierarchy.getBaseClass(_class)
+    if (baseClass !== _class) {
+      // Mixin operation is required.
+      const tx = txFactory.createTxMixin(_id, attachedTo._class, attachedTo.space, _class, update)
+      tx.modifiedOn = modifiedOn
+
+      return tx
+    } else {
+      const tx = txFactory.createTxUpdateDoc(_class, attachedTo.space, _id, update)
+      tx.modifiedOn = modifiedOn
+
+      return tx
+    }
+  }
+
+  private async updateCollection (ctx: MeasureContext, tx: Tx): Promise<Tx[]> {
+    if (tx._class !== core.class.TxCollectionCUD) {
+      return []
+    }
+
+    const colTx = tx as TxCollectionCUD<Doc, AttachedDoc>
+    const _id = colTx.objectId
+    const _class = colTx.objectClass
+    const { operations } = colTx.tx as TxUpdateDoc<AttachedDoc>
+
+    if (
+      colTx.tx._class !== core.class.TxUpdateDoc ||
+      this.hierarchy.getDomain(_class) === DOMAIN_MODEL // We could not update increments for model classes
+    ) {
+      return []
+    }
+
+    if (operations?.attachedTo === undefined || operations.attachedTo === _id) {
+      return []
+    }
+
+    const oldAttachedTo = (await this.findAll(ctx, _class, { _id }, { limit: 1 }))[0]
+    let oldTx: Tx | null = null
+    if (oldAttachedTo !== undefined) {
+      oldTx = await this.getCollectionUpdateTx(_id, _class, tx.modifiedBy, colTx.modifiedOn, oldAttachedTo, {
+        $inc: { [colTx.collection]: -1 }
+      })
+    }
+
+    const newAttachedToClass = operations.attachedToClass ?? _class
+    const newAttachedToCollection = operations.collection ?? colTx.collection
+    const newAttachedTo = (await this.findAll(ctx, newAttachedToClass, { _id: operations.attachedTo }, { limit: 1 }))[0]
+    let newTx: Tx | null = null
+    if (newAttachedTo !== undefined) {
+      newTx = await this.getCollectionUpdateTx(
+        newAttachedTo._id,
+        newAttachedTo._class,
+        tx.modifiedBy,
+        colTx.modifiedOn,
+        newAttachedTo,
+        { $inc: { [newAttachedToCollection]: 1 } }
+      )
+    }
+
+    return [...(oldTx !== null ? [oldTx] : []), ...(newTx !== null ? [newTx] : [])]
+  }
+
   async processCollection (ctx: MeasureContext, tx: Tx): Promise<Tx[]> {
     if (tx._class === core.class.TxCollectionCUD) {
       const colTx = tx as TxCollectionCUD<Doc, AttachedDoc>
       const _id = colTx.objectId
       const _class = colTx.objectClass
-      let attachedTo: Doc | undefined
 
       // Skip model operations
       if (this.hierarchy.getDomain(_class) === DOMAIN_MODEL) {
@@ -139,26 +211,20 @@ class TServerStorage implements ServerStorage {
       }
 
       const isCreateTx = colTx.tx._class === core.class.TxCreateDoc
-      if (isCreateTx || colTx.tx._class === core.class.TxRemoveDoc) {
-        attachedTo = (await this.findAll(ctx, _class, { _id }, { limit: 1 }))[0]
-        if (attachedTo !== undefined) {
-          const txFactory = new TxFactory(tx.modifiedBy)
-          const baseClass = this.hierarchy.getBaseClass(_class)
-          if (baseClass !== _class) {
-            // Mixin opeeration is required.
-            const tx = txFactory.createTxMixin(_id, attachedTo._class, attachedTo.space, _class, {
-              $inc: { [colTx.collection]: isCreateTx ? 1 : -1 }
-            })
-            tx.modifiedOn = colTx.modifiedOn
+      const isDeleteTx = colTx.tx._class === core.class.TxRemoveDoc
+      const isUpdateTx = colTx.tx._class === core.class.TxUpdateDoc
 
-            return [tx]
-          } else {
-            const tx = txFactory.createTxUpdateDoc(_class, attachedTo.space, _id, {
-              $inc: { [colTx.collection]: isCreateTx ? 1 : -1 }
-            })
-            tx.modifiedOn = colTx.modifiedOn
-
-            return [tx]
+      if (isCreateTx || isDeleteTx || isUpdateTx) {
+        if (isUpdateTx) {
+          return await this.updateCollection(ctx, tx)
+        } else {
+          const attachedTo = (await this.findAll(ctx, _class, { _id }, { limit: 1 }))[0]
+          if (attachedTo !== undefined) {
+            return [
+              await this.getCollectionUpdateTx(_id, _class, tx.modifiedBy, colTx.modifiedOn, attachedTo, {
+                $inc: { [colTx.collection]: isCreateTx ? 1 : -1 }
+              })
+            ]
           }
         }
       }