From 64c10f9effd51b45e528e90b84fb67104e528a3e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ivar=20Conradi=20=C3=98sthus?= <ivar@getunleash.io>
Date: Wed, 8 May 2024 14:20:51 +0200
Subject: [PATCH] poc: many strategies pagination (#7011)

This fixes the case when a customer have thousands of strategies causing
the react UI to crash. We still consider it incorrect to use that amount
of strategies and this is more a workaround to help the customer out of
a crashing state.

We put it behind a flag called `manyStrategiesPagination` and plan to
only enable it for the customer in trouble.
---
 .../EnvironmentAccordionBody.tsx              |  97 ++++++++++---
 .../StrategyNonDraggableItem.tsx              | 131 ++++++++++++++++++
 frontend/src/hooks/usePagination.ts           |   2 +-
 frontend/src/hooks/usePlausibleTracker.ts     |   1 +
 frontend/src/interfaces/uiConfig.ts           |   1 +
 .../__snapshots__/create-config.test.ts.snap  |   1 +
 src/lib/types/experimental.ts                 |   5 +
 src/server-dev.ts                             |   1 +
 8 files changed, 222 insertions(+), 17 deletions(-)
 create mode 100644 frontend/src/component/feature/FeatureView/FeatureOverview/FeatureOverviewEnvironments/FeatureOverviewEnvironment/EnvironmentAccordionBody/StrategyDraggableItem/StrategyNonDraggableItem.tsx

diff --git a/frontend/src/component/feature/FeatureView/FeatureOverview/FeatureOverviewEnvironments/FeatureOverviewEnvironment/EnvironmentAccordionBody/EnvironmentAccordionBody.tsx b/frontend/src/component/feature/FeatureView/FeatureOverview/FeatureOverviewEnvironments/FeatureOverviewEnvironment/EnvironmentAccordionBody/EnvironmentAccordionBody.tsx
index 11ef8e68bb..5f1b33c5ef 100644
--- a/frontend/src/component/feature/FeatureView/FeatureOverview/FeatureOverviewEnvironments/FeatureOverviewEnvironment/EnvironmentAccordionBody/EnvironmentAccordionBody.tsx
+++ b/frontend/src/component/feature/FeatureView/FeatureOverview/FeatureOverviewEnvironments/FeatureOverviewEnvironment/EnvironmentAccordionBody/EnvironmentAccordionBody.tsx
@@ -4,7 +4,7 @@ import {
     useEffect,
     useState,
 } from 'react';
-import { Alert, styled } from '@mui/material';
+import { Alert, Pagination, styled } from '@mui/material';
 import useFeatureStrategyApi from 'hooks/api/actions/useFeatureStrategyApi/useFeatureStrategyApi';
 import { formatUnknownError } from 'utils/formatUnknownError';
 import useToast from 'hooks/useToast';
@@ -17,6 +17,11 @@ import { useFeature } from 'hooks/api/getters/useFeature/useFeature';
 import { useChangeRequestApi } from 'hooks/api/actions/useChangeRequestApi/useChangeRequestApi';
 import { useChangeRequestsEnabled } from 'hooks/useChangeRequestsEnabled';
 import { usePendingChangeRequests } from 'hooks/api/getters/usePendingChangeRequests/usePendingChangeRequests';
+import usePagination from 'hooks/usePagination';
+import type { IFeatureStrategy } from 'interfaces/strategy';
+import { StrategyNonDraggableItem } from './StrategyDraggableItem/StrategyNonDraggableItem';
+import { usePlausibleTracker } from 'hooks/usePlausibleTracker';
+import { useUiFlag } from 'hooks/useUiFlag';
 
 interface IEnvironmentAccordionBodyProps {
     isDisabled: boolean;
@@ -50,9 +55,12 @@ const EnvironmentAccordionBody = ({
         usePendingChangeRequests(projectId);
     const { setToastData, setToastApiError } = useToast();
     const { refetchFeature } = useFeature(projectId, featureId);
+    const manyStrategiesPagination = useUiFlag('manyStrategiesPagination');
     const [strategies, setStrategies] = useState(
         featureEnvironment?.strategies || [],
     );
+    const { trackEvent } = usePlausibleTracker();
+
     const [dragItem, setDragItem] = useState<{
         id: string;
         index: number;
@@ -63,10 +71,20 @@ const EnvironmentAccordionBody = ({
         setStrategies(featureEnvironment?.strategies || []);
     }, [featureEnvironment?.strategies]);
 
+    useEffect(() => {
+        if (strategies.length > 50) {
+            trackEvent('many-strategies');
+        }
+    }, []);
+
     if (!featureEnvironment) {
         return null;
     }
 
+    const pageSize = 20;
+    const { page, pages, setPageIndex, pageIndex } =
+        usePagination<IFeatureStrategy>(strategies, pageSize);
+
     const onReorder = async (payload: { id: string; sortOrder: number }[]) => {
         try {
             await setStrategiesSortOrder(
@@ -195,21 +213,68 @@ const EnvironmentAccordionBody = ({
                 <ConditionallyRender
                     condition={strategies.length > 0}
                     show={
-                        <>
-                            {strategies.map((strategy, index) => (
-                                <StrategyDraggableItem
-                                    key={strategy.id}
-                                    strategy={strategy}
-                                    index={index}
-                                    environmentName={featureEnvironment.name}
-                                    otherEnvironments={otherEnvironments}
-                                    isDragging={dragItem?.id === strategy.id}
-                                    onDragStartRef={onDragStartRef}
-                                    onDragOver={onDragOver(strategy.id)}
-                                    onDragEnd={onDragEnd}
-                                />
-                            ))}
-                        </>
+                        <ConditionallyRender
+                            condition={
+                                strategies.length < 50 ||
+                                !manyStrategiesPagination
+                            }
+                            show={
+                                <>
+                                    {strategies.map((strategy, index) => (
+                                        <StrategyDraggableItem
+                                            key={strategy.id}
+                                            strategy={strategy}
+                                            index={index}
+                                            environmentName={
+                                                featureEnvironment.name
+                                            }
+                                            otherEnvironments={
+                                                otherEnvironments
+                                            }
+                                            isDragging={
+                                                dragItem?.id === strategy.id
+                                            }
+                                            onDragStartRef={onDragStartRef}
+                                            onDragOver={onDragOver(strategy.id)}
+                                            onDragEnd={onDragEnd}
+                                        />
+                                    ))}
+                                </>
+                            }
+                            elseShow={
+                                <>
+                                    <Alert severity='error'>
+                                        We noticed you're using a high number of
+                                        activation strategies. To ensure a more
+                                        targeted approach, consider leveraging
+                                        constraints or segments.
+                                    </Alert>
+                                    <br />
+                                    {page.map((strategy, index) => (
+                                        <StrategyNonDraggableItem
+                                            key={strategy.id}
+                                            strategy={strategy}
+                                            index={index + pageIndex * pageSize}
+                                            environmentName={
+                                                featureEnvironment.name
+                                            }
+                                            otherEnvironments={
+                                                otherEnvironments
+                                            }
+                                        />
+                                    ))}
+                                    <br />
+                                    <Pagination
+                                        count={pages.length}
+                                        shape='rounded'
+                                        page={pageIndex + 1}
+                                        onChange={(_, page) =>
+                                            setPageIndex(page - 1)
+                                        }
+                                    />
+                                </>
+                            }
+                        />
                     }
                     elseShow={
                         <FeatureStrategyEmpty
diff --git a/frontend/src/component/feature/FeatureView/FeatureOverview/FeatureOverviewEnvironments/FeatureOverviewEnvironment/EnvironmentAccordionBody/StrategyDraggableItem/StrategyNonDraggableItem.tsx b/frontend/src/component/feature/FeatureView/FeatureOverview/FeatureOverviewEnvironments/FeatureOverviewEnvironment/EnvironmentAccordionBody/StrategyDraggableItem/StrategyNonDraggableItem.tsx
new file mode 100644
index 0000000000..8097167b2c
--- /dev/null
+++ b/frontend/src/component/feature/FeatureView/FeatureOverview/FeatureOverviewEnvironments/FeatureOverviewEnvironment/EnvironmentAccordionBody/StrategyDraggableItem/StrategyNonDraggableItem.tsx
@@ -0,0 +1,131 @@
+import { useRef } from 'react';
+import { Box, useMediaQuery, useTheme } from '@mui/material';
+import { ConditionallyRender } from 'component/common/ConditionallyRender/ConditionallyRender';
+import { StrategySeparator } from 'component/common/StrategySeparator/StrategySeparator';
+import type { IFeatureEnvironment } from 'interfaces/featureToggle';
+import type { IFeatureStrategy } from 'interfaces/strategy';
+import { StrategyItem } from './StrategyItem/StrategyItem';
+import { useRequiredPathParam } from 'hooks/useRequiredPathParam';
+import {
+    useStrategyChangesFromRequest,
+    type UseStrategyChangeFromRequestResult,
+} from './StrategyItem/useStrategyChangesFromRequest';
+import { ChangesScheduledBadge } from 'component/changeRequest/ModifiedInChangeRequestStatusBadge/ChangesScheduledBadge';
+import type { IFeatureChange } from 'component/changeRequest/changeRequest.types';
+import { Badge } from 'component/common/Badge/Badge';
+import {
+    type ScheduledChangeRequestViewModel,
+    useScheduledChangeRequestsWithStrategy,
+} from 'hooks/api/getters/useScheduledChangeRequestsWithStrategy/useScheduledChangeRequestsWithStrategy';
+
+interface IStrategyItemProps {
+    strategy: IFeatureStrategy;
+    environmentName: string;
+    index: number;
+    otherEnvironments?: IFeatureEnvironment['name'][];
+}
+
+/**
+ * @deprecated
+ */
+export const StrategyNonDraggableItem = ({
+    strategy,
+    index,
+    environmentName,
+    otherEnvironments,
+}: IStrategyItemProps) => {
+    const projectId = useRequiredPathParam('projectId');
+    const featureId = useRequiredPathParam('featureId');
+    const ref = useRef<HTMLDivElement>(null);
+    const strategyChangesFromRequest = useStrategyChangesFromRequest(
+        projectId,
+        featureId,
+        environmentName,
+        strategy.id,
+    );
+
+    const { changeRequests: scheduledChangesUsingStrategy } =
+        useScheduledChangeRequestsWithStrategy(projectId, strategy.id);
+
+    return (
+        <Box key={strategy.id} ref={ref} sx={{ opacity: '1' }}>
+            <ConditionallyRender
+                condition={index > 0}
+                show={<StrategySeparator text='OR' />}
+            />
+
+            <StrategyItem
+                strategy={strategy}
+                environmentId={environmentName}
+                otherEnvironments={otherEnvironments}
+                orderNumber={index + 1}
+                headerChildren={renderHeaderChildren(
+                    strategyChangesFromRequest,
+                    scheduledChangesUsingStrategy,
+                )}
+            />
+        </Box>
+    );
+};
+
+const ChangeRequestStatusBadge = ({
+    change,
+}: {
+    change: IFeatureChange | undefined;
+}) => {
+    const theme = useTheme();
+    const isSmallScreen = useMediaQuery(theme.breakpoints.down('sm'));
+
+    if (isSmallScreen) {
+        return null;
+    }
+
+    return (
+        <Box sx={{ mr: 1.5 }}>
+            <ConditionallyRender
+                condition={change?.action === 'updateStrategy'}
+                show={<Badge color='warning'>Modified in draft</Badge>}
+            />
+            <ConditionallyRender
+                condition={change?.action === 'deleteStrategy'}
+                show={<Badge color='error'>Deleted in draft</Badge>}
+            />
+        </Box>
+    );
+};
+
+const renderHeaderChildren = (
+    changes?: UseStrategyChangeFromRequestResult,
+    scheduledChanges?: ScheduledChangeRequestViewModel[],
+): JSX.Element[] => {
+    const badges: JSX.Element[] = [];
+    if (changes?.length === 0 && scheduledChanges?.length === 0) {
+        return [];
+    }
+
+    const draftChange = changes?.find(
+        ({ isScheduledChange }) => !isScheduledChange,
+    );
+
+    if (draftChange) {
+        badges.push(
+            <ChangeRequestStatusBadge
+                key={`draft-change#${draftChange.change.id}`}
+                change={draftChange.change}
+            />,
+        );
+    }
+
+    if (scheduledChanges && scheduledChanges.length > 0) {
+        badges.push(
+            <ChangesScheduledBadge
+                key='scheduled-changes'
+                scheduledChangeRequestIds={scheduledChanges.map(
+                    (scheduledChange) => scheduledChange.id,
+                )}
+            />,
+        );
+    }
+
+    return badges;
+};
diff --git a/frontend/src/hooks/usePagination.ts b/frontend/src/hooks/usePagination.ts
index 26eb244377..0c68b1a300 100644
--- a/frontend/src/hooks/usePagination.ts
+++ b/frontend/src/hooks/usePagination.ts
@@ -20,7 +20,7 @@ const usePagination = <T>(
         }
 
         const result = paginate(dataToPaginate, limit);
-        setPageIndex(0);
+        // setPageIndex(0);
         setPaginatedData(result);
         /* eslint-disable-next-line */
     }, [JSON.stringify(data), limit]);
diff --git a/frontend/src/hooks/usePlausibleTracker.ts b/frontend/src/hooks/usePlausibleTracker.ts
index 7bfd81c432..437907defd 100644
--- a/frontend/src/hooks/usePlausibleTracker.ts
+++ b/frontend/src/hooks/usePlausibleTracker.ts
@@ -59,6 +59,7 @@ export type CustomEvents =
     | 'search-bar'
     | 'sdk-reporting'
     | 'insights-share'
+    | 'many-strategies'
     | 'sdk-banner';
 
 export const usePlausibleTracker = () => {
diff --git a/frontend/src/interfaces/uiConfig.ts b/frontend/src/interfaces/uiConfig.ts
index 0b7b0d6bd3..a4e1ab3957 100644
--- a/frontend/src/interfaces/uiConfig.ts
+++ b/frontend/src/interfaces/uiConfig.ts
@@ -84,6 +84,7 @@ export type UiFlags = {
     createProjectWithEnvironmentConfig?: boolean;
     projectsListNewCards?: boolean;
     newCreateProjectUI?: boolean;
+    manyStrategiesPagination?: boolean;
 };
 
 export interface IVersionInfo {
diff --git a/src/lib/__snapshots__/create-config.test.ts.snap b/src/lib/__snapshots__/create-config.test.ts.snap
index 9ee96f098d..1418f441c5 100644
--- a/src/lib/__snapshots__/create-config.test.ts.snap
+++ b/src/lib/__snapshots__/create-config.test.ts.snap
@@ -122,6 +122,7 @@ exports[`should create default config 1`] = `
       "googleAuthEnabled": false,
       "killScheduledChangeRequestCache": false,
       "maintenanceMode": false,
+      "manyStrategiesPagination": false,
       "messageBanner": {
         "enabled": false,
         "name": "message-banner",
diff --git a/src/lib/types/experimental.ts b/src/lib/types/experimental.ts
index c203845baa..d9eec1c785 100644
--- a/src/lib/types/experimental.ts
+++ b/src/lib/types/experimental.ts
@@ -59,6 +59,7 @@ export type IFlagKey =
     | 'projectsListNewCards'
     | 'parseProjectFromSession'
     | 'createProjectWithEnvironmentConfig'
+    | 'manyStrategiesPagination'
     | 'newCreateProjectUI';
 
 export type IFlags = Partial<{ [key in IFlagKey]: boolean | Variant }>;
@@ -284,6 +285,10 @@ const flags: IFlags = {
         process.env.UNLEASH_EXPERIMENTAL_NEW_CREATE_PROJECT_UI,
         false,
     ),
+    manyStrategiesPagination: parseEnvVarBoolean(
+        process.env.UNLEASH_EXPERIMENTAL_MANY_STRATEGIES_PAGINATION,
+        false,
+    ),
 };
 
 export const defaultExperimentalOptions: IExperimentalOptions = {
diff --git a/src/server-dev.ts b/src/server-dev.ts
index 58f781649d..dac91205ad 100644
--- a/src/server-dev.ts
+++ b/src/server-dev.ts
@@ -54,6 +54,7 @@ process.nextTick(async () => {
                         projectsListNewCards: true,
                         parseProjectFromSession: true,
                         createProjectWithEnvironmentConfig: true,
+                        manyStrategiesPagination: true,
                     },
                 },
                 authentication: {