From d85ff74f31cad015b7caa446d84b38478749dd30 Mon Sep 17 00:00:00 2001
From: "Amy J. Ko" <ajko@uw.edu>
Date: Sun, 3 Mar 2024 11:56:03 -0800
Subject: [PATCH] Update links to chapters when chapter IDs change.

---
 CHANGELOG.md                                 |  1 +
 src/lib/components/page/Chapter.svelte       | 27 +++++++------
 src/lib/components/page/Contexts.ts          |  6 +--
 src/lib/components/page/EditionLoader.svelte | 38 +++++++++++++-----
 src/lib/models/book/Edition.ts               | 41 ++++++++++++++++----
 5 files changed, 82 insertions(+), 31 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index d5c23fe1..d3956db6 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -10,6 +10,7 @@
 ## Fixed
 
 -   Fixed issue where image alignment setting was not saved.
+-   Update links to chapters when chapter IDs change.
 
 # 0.6.5 - 2024-02-25
 
diff --git a/src/lib/components/page/Chapter.svelte b/src/lib/components/page/Chapter.svelte
index 1baba47e..060c04ee 100644
--- a/src/lib/components/page/Chapter.svelte
+++ b/src/lib/components/page/Chapter.svelte
@@ -121,7 +121,7 @@
                     history.pushState(
                         '',
                         document.title,
-                        window.location.pathname + window.location.search
+                        window.location.pathname + window.location.search,
                     );
                     observer.unobserve(entry.target);
                     highlightedID = undefined;
@@ -169,7 +169,7 @@
         // If there's a word we're trying to highlight in the URL path, scroll to the corresponding match.
         if (location.search) {
             const highlights = document.getElementsByClassName(
-                'bookish-text bookish-content-highlight'
+                'bookish-text bookish-content-highlight',
             );
             const num = getHighlightedNumber();
             if (
@@ -288,16 +288,19 @@
                             text={chapter.getID()}
                             label="Chapter URL ID editor"
                             save={// After the ID is edited, reload the page with the new URL.
-                            (newChapterID) => {
+                            async (newChapterID) => {
                                 if ($book) {
                                     setChapter(
                                         edition,
                                         chapter,
-                                        chapter.withChapterID(newChapterID)
+                                        chapter.withChapterID(newChapterID),
                                     );
                                     // Navigate to the new ID
                                     goto(
-                                        `/write/${$book.getID()}/${editionNumber}/${newChapterID}`
+                                        `/write/${$book.getID()}/${editionNumber}/${newChapterID}`,
+                                        {
+                                            keepFocus: true,
+                                        },
                                     );
                                 }
                             }}
@@ -306,9 +309,9 @@
                                 !/^[a-zA-Z0-9]+$/.test(newChapterID)
                                     ? 'Chapter IDs must be one or more letters or numbers'
                                     : chapter.getID() !== newChapterID &&
-                                      $edition?.hasChapter(newChapterID)
-                                    ? "There's already a chapter that has this ID."
-                                    : undefined}
+                                        $edition?.hasChapter(newChapterID)
+                                      ? "There's already a chapter that has this ID."
+                                      : undefined}
                             saveOnExit={true}
                         />
                     </Muted>
@@ -320,7 +323,7 @@
                             setChapter(
                                 edition,
                                 chapter,
-                                chapter.asNumbered(on)
+                                chapter.asNumbered(on),
                             )}
                     >
                         <ChapterNumber
@@ -347,7 +350,7 @@
                     setChapter(
                         edition,
                         chapter,
-                        chapter.withRenamedAuthor(index, text)
+                        chapter.withRenamedAuthor(index, text),
                     )}
                 remove={(index) =>
                     setChapter(edition, chapter, chapter.withoutAuthor(index))}
@@ -375,7 +378,7 @@
                                 ? setChapter(
                                       edition,
                                       chapter,
-                                      chapter.withAST(ast)
+                                      chapter.withAST(ast),
                                   )
                                 : undefined}
                         chapter={true}
@@ -426,7 +429,7 @@
             <Permissions
                 uids={chapter.uids}
                 inheriteduids={Array.from(
-                    new Set([...$edition.uids, ...($book ? $book.uids : [])])
+                    new Set([...$edition.uids, ...($book ? $book.uids : [])]),
                 )}
                 atleastone={false}
                 writable={isChapterEditable()}
diff --git a/src/lib/components/page/Contexts.ts b/src/lib/components/page/Contexts.ts
index 7b01770a..885aea04 100644
--- a/src/lib/components/page/Contexts.ts
+++ b/src/lib/components/page/Contexts.ts
@@ -67,12 +67,12 @@ export function getRoot() {
 export function setChapter(
     store: EditionStore,
     previous: Chapter,
-    chapter: Chapter,
+    revised: Chapter,
 ) {
     // Don't set if its the same chapter.
-    if (previous === chapter) return;
+    if (previous === revised) return;
     const edition = get(store);
-    if (edition) store.set(edition.withRevisedChapter(previous, chapter));
+    if (edition) store.set(edition.withRevisedChapter(previous, revised));
 }
 
 function isRouteWrite(): boolean {
diff --git a/src/lib/components/page/EditionLoader.svelte b/src/lib/components/page/EditionLoader.svelte
index 19760ada..7c50a82f 100644
--- a/src/lib/components/page/EditionLoader.svelte
+++ b/src/lib/components/page/EditionLoader.svelte
@@ -15,6 +15,8 @@
 
     export let write: boolean;
 
+    let currentEditionID: string | undefined;
+
     let auth = getUser();
     let book = getBook();
     let edition = getEdition();
@@ -43,12 +45,12 @@
             error = 'Unknown book.';
             return;
         } else {
-            const editionNumber = $page.params.editionid;
+            currentEditionID = $page.params.editionid;
             const latestPublished = !write;
 
             // Figure out which edition to load.
             let editionID;
-            if (editionNumber === undefined) {
+            if (currentEditionID === undefined) {
                 if (latestPublished) {
                     editionID = $book.getLatestPublishedEditionID();
                     if (editionID === undefined)
@@ -57,9 +59,11 @@
                     editionID = $book.getLatestEditionID();
                 }
             } else {
-                editionID = $book.getEditionNumberID(parseFloat(editionNumber));
+                editionID = $book.getEditionNumberID(
+                    parseFloat(currentEditionID),
+                );
                 if (editionID === undefined)
-                    error = `There is no ${editionNumber} edition of this book`;
+                    error = `There is no ${currentEditionID} edition of this book`;
             }
 
             // Listen to the doc for changes and listen to all of its chapters.
@@ -75,7 +79,7 @@
                             edition.set(undefined);
                             error = 'Unable to load edition';
                         }
-                    }
+                    },
                 );
 
                 chaptersUnsub = listenToChapters(
@@ -86,16 +90,32 @@
                         for (const [ref, text] of chapters)
                             chapterText.set(ref.id, text);
                         // Update the chapter text in the current edition.
-                        if ($edition)
+                        if ($edition) {
                             edition.set($edition.withChapterText(chapterText));
-                    }
+                        }
+                    },
                 );
             }
         }
     }
 
-    // Whenever the book or page changes, change the listener.
-    $: if ($page && $auth && $auth.user !== null) listen();
+    // Remember the chapter text whenever the edition changes, so we don't overwrite stale text.
+    // when other things change.
+    $: if ($edition) {
+        for (const chapter of $edition.chapters) {
+            if (chapter.ref && chapter.text !== null)
+                chapterText.set(chapter.ref.id, chapter.text);
+        }
+    }
+
+    // Whenever the book changes, change the listener.
+    $: if (
+        (currentEditionID === undefined ||
+            $page.params.editionid !== currentEditionID) &&
+        $auth &&
+        $auth.user !== null
+    )
+        listen();
 
     // When unmounted, unset the stores — no longer viewing a book.
     onDestroy(() => {
diff --git a/src/lib/models/book/Edition.ts b/src/lib/models/book/Edition.ts
index aa999932..6f45bb22 100644
--- a/src/lib/models/book/Edition.ts
+++ b/src/lib/models/book/Edition.ts
@@ -511,13 +511,40 @@ export default class Edition {
     }
 
     withRevisedChapter(previous: Chapter, edited: Chapter) {
-        const index = this.chapters.indexOf(previous);
-        if (index < 0) return this;
-        return this.withChapters([
-            ...this.chapters.slice(0, index),
-            edited,
-            ...this.chapters.slice(index + 1),
-        ]);
+        return this.withChapters(
+            this.chapters.map((chapter) => {
+                // Is this the edited chapter? Return the edited one.
+                if (chapter === previous) return edited;
+
+                // If it's a different chapter, did the chapter change it's ID? Change all links to the chapter to have the new ID.
+                if (previous.id !== edited.id) {
+                    // Start with the chapter as is.
+                    let newChapter = chapter;
+
+                    // Replace the chapter ID in the chapter's text.
+                    if (newChapter.text !== null) {
+                        const revisedText = newChapter.text.replaceAll(
+                            new RegExp(
+                                `\\|(${previous.id})(:[a-zA-Z0-9]+)?\\]`,
+                                'g',
+                            ),
+                            `|${edited.id}$2]`,
+                        );
+                        if (revisedText !== chapter.text) {
+                            newChapter = newChapter.withText(revisedText);
+                            console.log(
+                                'Updated chapter text: ' + newChapter.text,
+                            );
+                        }
+                    }
+
+                    // Return the possibily revised chapter.
+                    return newChapter;
+                }
+                // Otherwise, just return the chapter as is.
+                else return chapter;
+            }),
+        );
     }
 
     withoutRefs() {