enhance(frontend): add retention line chart

4 files changed, 146 insertions, 2 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index c38cb12c3b..eafed11eff 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -24,6 +24,7 @@ Meilisearchの設定に`index`が必要になりました。値はMisskeyサー�
 ### Client
 - ユーザーを指定してのノート検索が可能に
 - アカウント初期設定ウィザードにプライバシー設定を追加
+- リテンション率チャートに折れ線グラフを追加
 - Fix: ブラーエフェクトを有効にしている状態で高負荷になる問題を修正
 - Fix: カラーバーがリプライには表示されないのを修正
 - Fix: チャンネル内の検索ボックスが挙動不審な問題を修正
diff --git a/packages/frontend/src/components/MkInstanceStats.vue b/packages/frontend/src/components/MkInstanceStats.vue
index 0f87fef6b1..6fcd8f7811 100644
--- a/packages/frontend/src/components/MkInstanceStats.vue
+++ b/packages/frontend/src/components/MkInstanceStats.vue
@@ -52,9 +52,12 @@
 
 	<MkFoldableSection class="item">
 		<template #header>Retention rate</template>
-		<div class="_panel" :class="$style.retention">
+		<div class="_panel" :class="$style.retentionHeatmap">
 			<MkRetentionHeatmap/>
 		</div>
+		<div class="_panel" :class="$style.retentionLine">
+			<MkRetentionLineChart/>
+		</div>
 	</MkFoldableSection>
 
 	<MkFoldableSection class="item">
@@ -86,6 +89,7 @@ import { i18n } from '@/i18n';
 import MkHeatmap from '@/components/MkHeatmap.vue';
 import MkFoldableSection from '@/components/MkFoldableSection.vue';
 import MkRetentionHeatmap from '@/components/MkRetentionHeatmap.vue';
+import MkRetentionLineChart from '@/components/MkRetentionLineChart.vue';
 import { initChart } from '@/scripts/init-chart';
 
 initChart();
@@ -202,7 +206,12 @@ onMounted(() => {
 	margin-bottom: 16px;
 }
 
-.retention {
+.retentionHeatmap {
+	padding: 16px;
+	margin-bottom: 16px;
+}
+
+.retentionLine {
 	padding: 16px;
 	margin-bottom: 16px;
 }
diff --git a/packages/frontend/src/components/MkRetentionHeatmap.vue b/packages/frontend/src/components/MkRetentionHeatmap.vue
index 3f5f09f5d0..fc2bc5c87f 100644
--- a/packages/frontend/src/components/MkRetentionHeatmap.vue
+++ b/packages/frontend/src/components/MkRetentionHeatmap.vue
@@ -129,6 +129,10 @@ async function renderChart() {
 						autoSkip: false,
 						callback: (value, index, values) => value,
 					},
+					title: {
+						display: true,
+						text: 'Days later',
+					},
 				},
 				y: {
 					type: 'time',
diff --git a/packages/frontend/src/components/MkRetentionLineChart.vue b/packages/frontend/src/components/MkRetentionLineChart.vue
new file mode 100644
index 0000000000..8bd0279806
--- /dev/null
+++ b/packages/frontend/src/components/MkRetentionLineChart.vue
@@ -0,0 +1,130 @@
+<template>
+<canvas ref="chartEl"></canvas>
+</template>
+
+<script lang="ts" setup>
+import { onMounted, shallowRef } from 'vue';
+import { Chart } from 'chart.js';
+import tinycolor from 'tinycolor2';
+import { defaultStore } from '@/store';
+import { useChartTooltip } from '@/scripts/use-chart-tooltip';
+import { chartVLine } from '@/scripts/chart-vline';
+import { alpha } from '@/scripts/color';
+import { initChart } from '@/scripts/init-chart';
+import * as os from '@/os';
+
+initChart();
+
+const chartEl = shallowRef<HTMLCanvasElement>(null);
+
+const { handler: externalTooltipHandler } = useChartTooltip();
+
+let chartInstance: Chart;
+
+const getYYYYMMDD = (date: Date) => {
+	const y = date.getFullYear().toString().padStart(2, '0');
+	const m = (date.getMonth() + 1).toString().padStart(2, '0');
+	const d = date.getDate().toString().padStart(2, '0');
+	return `${y}/${m}/${d}`;
+};
+
+const getDate = (ymd: string) => {
+	const [y, m, d] = ymd.split('-').map(x => parseInt(x, 10));
+	const date = new Date(y, m + 1, d, 0, 0, 0, 0);
+	return date;
+};
+
+onMounted(async () => {
+	let raw = await os.api('retention', { });
+
+	const vLineColor = defaultStore.state.darkMode ? 'rgba(255, 255, 255, 0.2)' : 'rgba(0, 0, 0, 0.2)';
+
+	const accent = tinycolor(getComputedStyle(document.documentElement).getPropertyValue('--accent'));
+	const color = accent.toHex();
+
+	chartInstance = new Chart(chartEl.value, {
+		type: 'line',
+		data: {
+			labels: [],
+			datasets: raw.map((record, i) => ({
+				label: getYYYYMMDD(new Date(record.createdAt)),
+				pointRadius: 0,
+				borderWidth: 2,
+				borderJoinStyle: 'round',
+				borderColor: alpha(color, Math.min(1, (raw.length - (i - 1)) / raw.length)),
+				fill: false,
+				tension: 0.4,
+				data: [{
+					x: '0',
+					y: 100,
+					d: getYYYYMMDD(new Date(record.createdAt)),
+				}, ...Object.entries(record.data).sort((a, b) => getDate(a[0]) > getDate(b[0]) ? 1 : -1).map(([k, v], i) => ({
+					x: (i + 1).toString(),
+					y: (v / record.users) * 100,
+					d: getYYYYMMDD(new Date(record.createdAt)),
+				}))],
+			})),
+		},
+		options: {
+			aspectRatio: 2.5,
+			layout: {
+				padding: {
+					left: 0,
+					right: 0,
+					top: 0,
+					bottom: 0,
+				},
+			},
+			scales: {
+				x: {
+					title: {
+						display: true,
+						text: 'Days later',
+					},
+				},
+				y: {
+					title: {
+						display: true,
+						text: 'Rate (%)',
+					},
+					ticks: {
+						callback: (value, index, values) => value + '%',
+					},
+				},
+			},
+			interaction: {
+				intersect: false,
+			},
+			plugins: {
+				legend: {
+					display: false,
+				},
+				tooltip: {
+					enabled: false,
+					callbacks: {
+						title(context) {
+							const v = context[0].dataset.data[context[0].dataIndex];
+							return `${v.x} days later`;
+						},
+						label(context) {
+							const v = context.dataset.data[context.dataIndex];
+							const p = Math.round(v.y) + '%';
+							return `${v.d} ${p}`;
+						},
+					},
+					mode: 'index',
+					animation: {
+						duration: 0,
+					},
+					external: externalTooltipHandler,
+				},
+			},
+		},
+		plugins: [chartVLine(vLineColor)],
+	});
+});
+</script>
+
+<style lang="scss" scoped>
+
+</style>