From 8f3c0dce1e62df976189e2c10678a0513554a07f Mon Sep 17 00:00:00 2001
From: Konstantin Schaper <konstantin.schaper@cloudogu.com>
Date: Fri, 21 Aug 2020 18:27:48 +0200
Subject: [PATCH] initial implementation

---
 scm-ui/ui-components/src/repos/Diff.tsx     | 53 ++++++++++++++++++---
 scm-ui/ui-components/src/repos/DiffFile.tsx | 16 ++++++-
 2 files changed, 62 insertions(+), 7 deletions(-)

diff --git a/scm-ui/ui-components/src/repos/Diff.tsx b/scm-ui/ui-components/src/repos/Diff.tsx
index 5a0571e95f..f5086f2881 100644
--- a/scm-ui/ui-components/src/repos/Diff.tsx
+++ b/scm-ui/ui-components/src/repos/Diff.tsx
@@ -22,34 +22,75 @@
  * SOFTWARE.
  */
 import React from "react";
-import DiffFile from "./DiffFile";
+import DiffFile, {escapeWhitespace} from "./DiffFile";
 import { DiffObjectProps, File, FileControlFactory } from "./DiffTypes";
 import Notification from "../Notification";
 import { WithTranslation, withTranslation } from "react-i18next";
+import {RouteComponentProps, withRouter} from "react-router-dom";
 
-type Props = WithTranslation &
+type Props = RouteComponentProps & WithTranslation &
   DiffObjectProps & {
     diff: File[];
     fileControlFactory?: FileControlFactory;
   };
 
-class Diff extends React.Component<Props> {
+type State = {
+  contentRef?: HTMLElement;
+}
+
+function getAnchorSelector(uriHashContent: string) {
+  return "#" + escapeWhitespace(decodeURIComponent(uriHashContent));
+}
+
+class Diff extends React.Component<Props, State> {
   static defaultProps: Partial<Props> = {
     sideBySide: false
   };
 
+  constructor(props: Readonly<Props>) {
+    super(props);
+    this.state = {
+      contentRef: undefined
+    };
+  }
+
+  componentDidUpdate() {
+    const { contentRef } = this.state;
+
+    // we have to use componentDidUpdate, because we have to wait until all
+    // children are rendered and componentDidMount is called before the
+    // changeset content was rendered.
+    const hash = this.props.location.hash;
+    const match = hash && hash.match(/^#diff-(.*)$/);
+    if (contentRef && match) {
+      const selector = getAnchorSelector(match[1]);
+      const element = contentRef.querySelector(selector);
+      if (element && element.scrollIntoView) {
+        element.scrollIntoView();
+      }
+    }
+  }
+
   render() {
     const { diff, t, ...fileProps } = this.props;
+    const updateContentRef = (el: HTMLElement | null) => {
+      if (el !== null && this.state.contentRef === undefined) {
+        this.setState({ contentRef: el });
+      }
+    };
+
     return (
-      <>
+      <div
+        ref={updateContentRef}
+      >
         {diff.length === 0 ? (
           <Notification type="info">{t("diff.noDiffFound")}</Notification>
         ) : (
           diff.map((file, index) => <DiffFile key={index} file={file} {...fileProps} {...this.props} />)
         )}
-      </>
+      </div>
     );
   }
 }
 
-export default withTranslation("repos")(Diff);
+export default withRouter(withTranslation("repos")(Diff));
diff --git a/scm-ui/ui-components/src/repos/DiffFile.tsx b/scm-ui/ui-components/src/repos/DiffFile.tsx
index 637128fae9..91f87e821b 100644
--- a/scm-ui/ui-components/src/repos/DiffFile.tsx
+++ b/scm-ui/ui-components/src/repos/DiffFile.tsx
@@ -90,6 +90,10 @@ const ChangeTypeTag = styled(Tag)`
   margin-left: 0.75rem;
 `;
 
+export function escapeWhitespace(path: string) {
+  return path.toLowerCase().replace(/\W/g, "-");
+}
+
 class DiffFile extends React.Component<Props, State> {
   static defaultProps: Partial<Props> = {
     defaultCollapse: false,
@@ -350,6 +354,16 @@ class DiffFile extends React.Component<Props, State> {
     }
   };
 
+  getAnchorId(file: File) {
+    let path: string;
+    if (file.type === "delete") {
+      path = file.oldPath;
+    } else {
+      path = file.newPath;
+    }
+    return escapeWhitespace(path);
+  }
+
   renderFileTitle = (file: File) => {
     if (file.oldPath !== file.newPath && (file.type === "copy" || file.type === "rename")) {
       return (
@@ -454,7 +468,7 @@ class DiffFile extends React.Component<Props, State> {
     }
 
     return (
-      <DiffFilePanel className={classNames("panel", "is-size-6")} collapsed={(file && file.isBinary) || collapsed}>
+      <DiffFilePanel className={classNames("panel", "is-size-6")} collapsed={(file && file.isBinary) || collapsed} id={this.getAnchorId(file)}>
         {errorModal}
         <div className="panel-heading">
           <FlexWrapLevel className="level">