Implement code frequency graph (#29191)

### Overview
This is the implementation of Code Frequency page. This feature was
mentioned on these issues: #18262, #7392.

It adds another tab to Activity page called Code Frequency. Code
Frequency tab shows additions and deletions over time since the
repository existed.

Before:
<img width="1296" alt="image"
src="https://github.com/go-gitea/gitea/assets/32161460/2603504f-aee7-4929-a8c4-fb3412a7a0f6">

After:
<img width="1296" alt="image"
src="https://github.com/go-gitea/gitea/assets/32161460/58c03721-729f-4536-a663-9f337f240963">

---

#### Features
- See additions deletions over time since repository existed
- Click on "Additions" or "Deletions" legend to show only one type of
contribution
- Use the same cache from Contributors page so that the loading of data
will be fast once it is cached by visiting either one of the pages

---------

Co-authored-by: Giteabot <teabot@gitea.io>
(cherry picked from commit 875f5ea6d83c8371f309df99654ca3556623004c)

options/locale/locale_en-US.ini

@@ -1962,6 +1962,7 @@ wiki.original_git_entry_tooltip = View original Git file instead of using friend
 activity = Activity
 activity.navbar.pulse = Pulse
 activity.navbar.contributors = Contributors
+activity.navbar.code_frequency = Code Frequency
 activity.period.filter_label = Period:
 activity.period.daily = 1 day
 activity.period.halfweekly = 3 days
@@ -2656,6 +2657,7 @@ component_loading = Loading %s...
 component_loading_failed = Could not load %s
 component_loading_info = This might take a bit…
 component_failed_to_load = An unexpected error happened.
+code_frequency.what = code frequency
 contributors.what = contributions
 
 [org]

routers/web/repo/code_frequency.go

@@ -0,0 +1,41 @@
+// Copyright 2023 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package repo
+
+import (
+	"errors"
+	"net/http"
+
+	"code.gitea.io/gitea/modules/base"
+	"code.gitea.io/gitea/modules/context"
+	contributors_service "code.gitea.io/gitea/services/repository"
+)
+
+const (
+	tplCodeFrequency base.TplName = "repo/activity"
+)
+
+// CodeFrequency renders the page to show repository code frequency
+func CodeFrequency(ctx *context.Context) {
+	ctx.Data["Title"] = ctx.Tr("repo.activity.navbar.code_frequency")
+
+	ctx.Data["PageIsActivity"] = true
+	ctx.Data["PageIsCodeFrequency"] = true
+	ctx.PageData["repoLink"] = ctx.Repo.RepoLink
+
+	ctx.HTML(http.StatusOK, tplCodeFrequency)
+}
+
+// CodeFrequencyData returns JSON of code frequency data
+func CodeFrequencyData(ctx *context.Context) {
+	if contributorStats, err := contributors_service.GetContributorStats(ctx, ctx.Cache, ctx.Repo.Repository, ctx.Repo.CommitID); err != nil {
+		if errors.Is(err, contributors_service.ErrAwaitGeneration) {
+			ctx.Status(http.StatusAccepted)
+			return
+		}
+		ctx.ServerError("GetCodeFrequencyData", err)
+	} else {
+		ctx.JSON(http.StatusOK, contributorStats["total"].Weeks)
+	}
+}

routers/web/web.go

@@ -1448,6 +1448,10 @@ func registerRoutes(m *web.Route) {
 				m.Get("", repo.Contributors)
 				m.Get("/data", repo.ContributorsData)
 			})
+			m.Group("/code-frequency", func() {
+				m.Get("", repo.CodeFrequency)
+				m.Get("/data", repo.CodeFrequencyData)
+			})
 		}, context.RepoRef(), repo.MustBeNotEmpty, context.RequireRepoReaderOr(unit.TypePullRequests, unit.TypeIssues, unit.TypeReleases))
 
 		m.Group("/activity_author_data", func() {

services/repository/contributors_graph.go

@@ -143,7 +143,6 @@ func getExtendedCommitStats(repo *git.Repository, revision string /*, limit int
 		PipelineFunc: func(ctx context.Context, cancel context.CancelFunc) error {
 			_ = stdoutWriter.Close()
 			scanner := bufio.NewScanner(stdoutReader)
-			scanner.Split(bufio.ScanLines)
 
 			for scanner.Scan() {
 				line := strings.TrimSpace(scanner.Text())
@@ -180,7 +179,6 @@ func getExtendedCommitStats(repo *git.Repository, revision string /*, limit int
 					}
 				}
 				commitStats.Total = commitStats.Additions + commitStats.Deletions
-				scanner.Scan()
 				scanner.Text() // empty line at the end
 
 				res := &ExtendedCommitStats{

templates/repo/activity.tmpl

@@ -8,6 +8,7 @@
 		<div class="flex-container-main">
 			{{if .PageIsPulse}}{{template "repo/pulse" .}}{{end}}
 			{{if .PageIsContributors}}{{template "repo/contributors" .}}{{end}}
+			{{if .PageIsCodeFrequency}}{{template "repo/code_frequency" .}}{{end}}
 		</div>
 	</div>
 </div>

templates/repo/code_frequency.tmpl

@@ -0,0 +1,9 @@
+{{if .Permission.CanRead $.UnitTypeCode}}
+	<div id="repo-code-frequency-chart"
+		data-locale-loading-title="{{ctx.Locale.Tr "graphs.component_loading" (ctx.Locale.Tr "graphs.code_frequency.what")}}"
+		data-locale-loading-title-failed="{{ctx.Locale.Tr "graphs.component_loading_failed" (ctx.Locale.Tr "graphs.code_frequency.what")}}"
+		data-locale-loading-info="{{ctx.Locale.Tr "graphs.component_loading_info"}}"
+		data-locale-component-failed-to-load="{{ctx.Locale.Tr "graphs.component_failed_to_load"}}"
+	>
+	</div>
+{{end}}

templates/repo/navbar.tmpl

@@ -5,4 +5,7 @@
 	<a class="{{if .PageIsContributors}}active {{end}}item" href="{{.RepoLink}}/activity/contributors">
 		{{ctx.Locale.Tr "repo.activity.navbar.contributors"}}
 	</a>
+	<a class="{{if .PageIsCodeFrequency}}active{{end}} item" href="{{.RepoLink}}/activity/code-frequency">
+		{{ctx.Locale.Tr "repo.activity.navbar.code_frequency"}}
+	</a>
 </div>

web_src/js/components/RepoCodeFrequency.vue

@@ -0,0 +1,172 @@
+<script>
+import {SvgIcon} from '../svg.js';
+import {
+  Chart,
+  Legend,
+  LinearScale,
+  TimeScale,
+  PointElement,
+  LineElement,
+  Filler,
+} from 'chart.js';
+import {GET} from '../modules/fetch.js';
+import {Line as ChartLine} from 'vue-chartjs';
+import {
+  startDaysBetween,
+  firstStartDateAfterDate,
+  fillEmptyStartDaysWithZeroes,
+} from '../utils/time.js';
+import {chartJsColors} from '../utils/color.js';
+import {sleep} from '../utils.js';
+import 'chartjs-adapter-dayjs-4/dist/chartjs-adapter-dayjs-4.esm';
+
+const {pageData} = window.config;
+
+Chart.defaults.color = chartJsColors.text;
+Chart.defaults.borderColor = chartJsColors.border;
+
+Chart.register(
+  TimeScale,
+  LinearScale,
+  Legend,
+  PointElement,
+  LineElement,
+  Filler,
+);
+
+export default {
+  components: {ChartLine, SvgIcon},
+  props: {
+    locale: {
+      type: Object,
+      required: true
+    },
+  },
+  data: () => ({
+    isLoading: false,
+    errorText: '',
+    repoLink: pageData.repoLink || [],
+    data: [],
+  }),
+  mounted() {
+    this.fetchGraphData();
+  },
+  methods: {
+    async fetchGraphData() {
+      this.isLoading = true;
+      try {
+        let response;
+        do {
+          response = await GET(`${this.repoLink}/activity/code-frequency/data`);
+          if (response.status === 202) {
+            await sleep(1000); // wait for 1 second before retrying
+          }
+        } while (response.status === 202);
+        if (response.ok) {
+          this.data = await response.json();
+          const weekValues = Object.values(this.data);
+          const start = weekValues[0].week;
+          const end = firstStartDateAfterDate(new Date());
+          const startDays = startDaysBetween(new Date(start), new Date(end));
+          this.data = fillEmptyStartDaysWithZeroes(startDays, this.data);
+          this.errorText = '';
+        } else {
+          this.errorText = response.statusText;
+        }
+      } catch (err) {
+        this.errorText = err.message;
+      } finally {
+        this.isLoading = false;
+      }
+    },
+
+    toGraphData(data) {
+      return {
+        datasets: [
+          {
+            data: data.map((i) => ({x: i.week, y: i.additions})),
+            pointRadius: 0,
+            pointHitRadius: 0,
+            fill: true,
+            label: 'Additions',
+            backgroundColor: chartJsColors['additions'],
+            borderWidth: 0,
+            tension: 0.3,
+          },
+          {
+            data: data.map((i) => ({x: i.week, y: -i.deletions})),
+            pointRadius: 0,
+            pointHitRadius: 0,
+            fill: true,
+            label: 'Deletions',
+            backgroundColor: chartJsColors['deletions'],
+            borderWidth: 0,
+            tension: 0.3,
+          },
+        ],
+      };
+    },
+
+    getOptions() {
+      return {
+        responsive: true,
+        maintainAspectRatio: false,
+        animation: true,
+        plugins: {
+          legend: {
+            display: true,
+          },
+        },
+        scales: {
+          x: {
+            type: 'time',
+            grid: {
+              display: false,
+            },
+            time: {
+              minUnit: 'month',
+            },
+            ticks: {
+              maxRotation: 0,
+              maxTicksLimit: 12
+            },
+          },
+          y: {
+            ticks: {
+              maxTicksLimit: 6
+            },
+          },
+        },
+      };
+    },
+  },
+};
+</script>
+<template>
+  <div>
+    <div class="ui header gt-df gt-ac gt-sb">
+      {{ isLoading ? locale.loadingTitle : errorText ? locale.loadingTitleFailed: `Code frequency over the history of ${repoLink.slice(1)}` }}
+    </div>
+    <div class="gt-df ui segment main-graph">
+      <div v-if="isLoading || errorText !== ''" class="gt-tc gt-m-auto">
+        <div v-if="isLoading">
+          <SvgIcon name="octicon-sync" class="gt-mr-3 job-status-rotate"/>
+          {{ locale.loadingInfo }}
+        </div>
+        <div v-else class="text red">
+          <SvgIcon name="octicon-x-circle-fill"/>
+          {{ errorText }}
+        </div>
+      </div>
+      <ChartLine
+        v-memo="data" v-if="data.length !== 0"
+        :data="toGraphData(data)" :options="getOptions()"
+      />
+    </div>
+  </div>
+</template>
+<style scoped>
+.main-graph {
+  height: 440px;
+}
+</style>

web_src/js/components/RepoContributors.vue

@@ -3,10 +3,7 @@ import {SvgIcon} from '../svg.js';
 import {
   Chart,
   Title,
-  Tooltip,
-  Legend,
   BarElement,
-  CategoryScale,
   LinearScale,
   TimeScale,
   PointElement,
@@ -21,27 +18,13 @@ import {
   firstStartDateAfterDate,
   fillEmptyStartDaysWithZeroes,
 } from '../utils/time.js';
+import {chartJsColors} from '../utils/color.js';
+import {sleep} from '../utils.js';
 import 'chartjs-adapter-dayjs-4/dist/chartjs-adapter-dayjs-4.esm';
 import $ from 'jquery';
 
 const {pageData} = window.config;
 
-const colors = {
-  text: '--color-text',
-  border: '--color-secondary-alpha-60',
-  commits: '--color-primary-alpha-60',
-  additions: '--color-green',
-  deletions: '--color-red',
-  title: '--color-secondary-dark-4',
-};
-
-const styles = window.getComputedStyle(document.documentElement);
-const getColor = (name) => styles.getPropertyValue(name).trim();
-
-for (const [key, value] of Object.entries(colors)) {
-  colors[key] = getColor(value);
-}
-
 const customEventListener = {
   id: 'customEventListener',
   afterEvent: (chart, args, opts) => {
@@ -54,17 +37,14 @@ const customEventListener = {
   }
 };
 
-Chart.defaults.color = colors.text;
+Chart.defaults.color = chartJsColors.text;
-Chart.defaults.borderColor = colors.border;
+Chart.defaults.borderColor = chartJsColors.border;
 
 Chart.register(
   TimeScale,
-  CategoryScale,
   LinearScale,
   BarElement,
   Title,
-  Tooltip,
-  Legend,
   PointElement,
   LineElement,
   Filler,
@@ -122,7 +102,7 @@ export default {
         do {
           response = await GET(`${this.repoLink}/activity/contributors/data`);
           if (response.status === 202) {
-            await new Promise((resolve) => setTimeout(resolve, 1000)); // wait for 1 second before retrying
+            await sleep(1000); // wait for 1 second before retrying
           }
         } while (response.status === 202);
         if (response.ok) {
@@ -222,7 +202,7 @@ export default {
             pointRadius: 0,
             pointHitRadius: 0,
             fill: 'start',
-            backgroundColor: colors[this.type],
+            backgroundColor: chartJsColors[this.type],
             borderWidth: 0,
             tension: 0.3,
           },
@@ -254,7 +234,6 @@ export default {
           title: {
             display: type === 'main',
             text: 'drag: zoom, shift+drag: pan, double click: reset zoom',
-            color: colors.title,
             position: 'top',
             align: 'center',
           },
@@ -262,9 +241,6 @@ export default {
             chartType: type,
             instance: this,
           },
-          legend: {
-            display: false,
-          },
           zoom: {
             pan: {
               enabled: true,

web_src/js/features/code-frequency.js

@@ -0,0 +1,21 @@
+import {createApp} from 'vue';
+
+export async function initRepoCodeFrequency() {
+  const el = document.getElementById('repo-code-frequency-chart');
+  if (!el) return;
+
+  const {default: RepoCodeFrequency} = await import(/* webpackChunkName: "code-frequency-graph" */'../components/RepoCodeFrequency.vue');
+  try {
+    const View = createApp(RepoCodeFrequency, {
+      locale: {
+        loadingTitle: el.getAttribute('data-locale-loading-title'),
+        loadingTitleFailed: el.getAttribute('data-locale-loading-title-failed'),
+        loadingInfo: el.getAttribute('data-locale-loading-info'),
+      }
+    });
+    View.mount(el);
+  } catch (err) {
+    console.error('RepoCodeFrequency failed to load', err);
+    el.textContent = el.getAttribute('data-locale-component-failed-to-load');
+  }
+}

web_src/js/index.js

@@ -84,6 +84,7 @@ import {onDomReady} from './utils/dom.js';
 import {initRepoIssueList} from './features/repo-issue-list.js';
 import {initCommonIssueListQuickGoto} from './features/common-issue-list.js';
 import {initRepoContributors} from './features/contributors.js';
+import {initRepoCodeFrequency} from './features/code-frequency.js';
 import {initRepoDiffCommitBranchesAndTags} from './features/repo-diff-commit.js';
 import {initDirAuto} from './modules/dirauto.js';
 
@@ -174,6 +175,7 @@ onDomReady(() => {
   initRepository();
   initRepositoryActionView();
   initRepoContributors();
+  initRepoCodeFrequency();
 
   initCommitStatuses();
   initCaptcha();

web_src/js/utils.js

@@ -139,3 +139,5 @@ export function parseDom(text, contentType) {
 export function serializeXml(node) {
   return xmlSerializer.serializeToString(node);
 }
+
+export const sleep = (ms) => new Promise((resolve) => setTimeout(resolve, ms));

web_src/js/utils/color.js

@@ -19,3 +19,17 @@ function getLuminance(r, g, b) {
 export function useLightTextOnBackground(r, g, b) {
   return getLuminance(r, g, b) < 0.453;
 }
+
+function resolveColors(obj) {
+  const styles = window.getComputedStyle(document.documentElement);
+  const getColor = (name) => styles.getPropertyValue(name).trim();
+  return Object.fromEntries(Object.entries(obj).map(([key, value]) => [key, getColor(value)]));
+}
+
+export const chartJsColors = resolveColors({
+  text: '--color-text',
+  border: '--color-secondary-alpha-60',
+  commits: '--color-primary-alpha-60',
+  additions: '--color-green',
+  deletions: '--color-red',
+});