Version picker added for v1.98 docs

6 files changed, 230 insertions, 2 deletions

diff --git a/book.toml b/book.toml
index ed3f6151e0..977a8450bc 100644
--- a/book.toml
+++ b/book.toml
@@ -34,8 +34,13 @@ additional-css = [
     "docs/website_files/table-of-contents.css",
     "docs/website_files/remove-nav-buttons.css",
     "docs/website_files/indent-section-headers.css",
+    "docs/website_files/version-picker.css",
+]
+additional-js = [
+    "docs/website_files/table-of-contents.js",
+    "docs/website_files/version-picker.js",
+    "docs/website_files/version.js",
 ]
-additional-js = ["docs/website_files/table-of-contents.js"]
 theme = "docs/website_files/theme"
 
 [preprocessor.schema_versions]
diff --git a/docs/website_files/README.md b/docs/website_files/README.md
index 04d191479b..bc51c4865e 100644
--- a/docs/website_files/README.md
+++ b/docs/website_files/README.md
@@ -24,6 +24,11 @@ Finally, we also stylise the chapter titles in the left sidebar by indenting the
 slightly so that they are more visually distinguishable from the section headers
 (the bold titles). This is done through the `indent-section-headers.css` file.
 
+In addition to these modifications, we have added a version picker to the documentation.
+Users can switch between documentations for different versions of Synapse.
+This functionality was implemented through the `version-picker.js` and
+`version-picker.css` files.
+
 More information can be found in mdbook's official documentation for
 [injecting page JS/CSS](https://rust-lang.github.io/mdBook/format/config.html)
 and
diff --git a/docs/website_files/theme/index.hbs b/docs/website_files/theme/index.hbs
index 3b7a5b6163..b169323a43 100644
--- a/docs/website_files/theme/index.hbs
+++ b/docs/website_files/theme/index.hbs
@@ -131,6 +131,18 @@
                             <i class="fa fa-search"></i>
                         </button>
                         {{/if}}
+                        <div class="version-picker">
+                            <div class="dropdown">
+                                <div class="select">
+                                    <span></span>
+                                    <i class="fa fa-chevron-down"></i>
+                                </div>
+                                <input type="hidden" name="version">
+                                <ul class="dropdown-menu">
+                                    <!-- Versions will be added dynamically in version-picker.js -->
+                                </ul>
+                            </div>
+                        </div>      
                     </div>
 
                     <h1 class="menu-title">{{ book_title }}</h1>
@@ -309,4 +321,4 @@
         {{/if}}
 
     </body>
-</html>
\ No newline at end of file
+</html>
diff --git a/docs/website_files/version-picker.css b/docs/website_files/version-picker.css
new file mode 100644
index 0000000000..28e5d5219a
--- /dev/null
+++ b/docs/website_files/version-picker.css
@@ -0,0 +1,78 @@
+.version-picker {
+    display: flex;
+    align-items: center;
+}
+
+.version-picker .dropdown {
+    width: 130px;
+    max-height: 29px;
+    margin-left: 10px;
+    display: inline-block;
+    border-radius: 4px;
+    border: 1px solid var(--theme-popup-border);
+    position: relative;
+    font-size: 13px;
+    color: var(--fg);
+    height: 100%;
+    text-align: left;
+}
+.version-picker .dropdown .select {
+    cursor: pointer;
+    display: block;
+    padding: 5px 2px 5px 15px;
+}
+.version-picker .dropdown .select > i {
+    font-size: 10px;
+    color: var(--fg);
+    cursor: pointer;
+    float: right;
+    line-height: 20px !important;
+}
+.version-picker .dropdown:hover {
+    border: 1px solid var(--theme-popup-border);
+}
+.version-picker .dropdown:active {
+    background-color: var(--theme-popup-bg);
+}
+.version-picker .dropdown.active:hover,
+.version-picker .dropdown.active {
+    border: 1px solid var(--theme-popup-border);
+    border-radius: 2px 2px 0 0;
+    background-color: var(--theme-popup-bg);
+}
+.version-picker .dropdown.active .select > i {
+    transform: rotate(-180deg);
+}
+.version-picker .dropdown .dropdown-menu {
+    position: absolute;
+    background-color: var(--theme-popup-bg);
+    width: 100%;
+    left: -1px;
+    right: 1px;
+    margin-top: 1px;
+    border: 1px solid var(--theme-popup-border);
+    border-radius: 0 0 4px 4px;
+    overflow: hidden;
+    display: none;
+    max-height: 300px;
+    overflow-y: auto;
+    z-index: 9;
+}
+.version-picker .dropdown .dropdown-menu li {
+    font-size: 12px;
+    padding: 6px 20px;
+    cursor: pointer;
+} 
+.version-picker .dropdown .dropdown-menu {
+    padding: 0;
+    list-style: none;
+}
+.version-picker .dropdown .dropdown-menu li:hover {
+    background-color: var(--theme-hover);
+}
+.version-picker .dropdown .dropdown-menu li.active::before {
+    display: inline-block;
+    content: "✓";
+    margin-inline-start: -14px;
+    width: 14px;
+}
\ No newline at end of file
diff --git a/docs/website_files/version-picker.js b/docs/website_files/version-picker.js
new file mode 100644
index 0000000000..bb35a7d896
--- /dev/null
+++ b/docs/website_files/version-picker.js
@@ -0,0 +1,127 @@
+
+const dropdown = document.querySelector('.version-picker .dropdown');
+const dropdownMenu = dropdown.querySelector('.dropdown-menu');
+
+fetchVersions(dropdown, dropdownMenu).then(() => {
+    initializeVersionDropdown(dropdown, dropdownMenu);
+});
+
+/**
+ * Initialize the dropdown functionality for version selection.
+ * 
+ * @param {Element} dropdown - The dropdown element.
+ * @param {Element} dropdownMenu - The dropdown menu element.
+ */
+function initializeVersionDropdown(dropdown, dropdownMenu) {
+    // Toggle the dropdown menu on click
+    dropdown.addEventListener('click', function () {
+        this.setAttribute('tabindex', 1);
+        this.classList.toggle('active');
+        dropdownMenu.style.display = (dropdownMenu.style.display === 'block') ? 'none' : 'block';
+    });
+  
+    // Remove the 'active' class and hide the dropdown menu on focusout
+    dropdown.addEventListener('focusout', function () {
+        this.classList.remove('active');
+        dropdownMenu.style.display = 'none';
+    });
+  
+    // Handle item selection within the dropdown menu
+    const dropdownMenuItems = dropdownMenu.querySelectorAll('li');    
+    dropdownMenuItems.forEach(function (item) {
+        item.addEventListener('click', function () {
+            dropdownMenuItems.forEach(function (item) {
+                item.classList.remove('active');
+            });
+            this.classList.add('active');
+            dropdown.querySelector('span').textContent = this.textContent;
+            dropdown.querySelector('input').value = this.getAttribute('id');
+
+            window.location.href = changeVersion(window.location.href, this.textContent);
+        });
+    });
+};
+
+/**
+ * This function fetches the available versions from a GitHub repository
+ * and inserts them into the version picker.
+ * 
+ * @param {Element} dropdown - The dropdown element.
+ * @param {Element} dropdownMenu - The dropdown menu element.
+ * @returns {Promise<Array<string>>} A promise that resolves with an array of available versions.
+ */
+function fetchVersions(dropdown, dropdownMenu) {
+    return new Promise((resolve, reject) => {
+        window.addEventListener("load", () => {
+
+            fetch("https://api.github.com/repos/matrix-org/synapse/git/trees/gh-pages", {
+                cache: "force-cache",
+            }).then(res => 
+                res.json()
+            ).then(resObject => {
+                const excluded = ['dev-docs', 'v1.91.0', 'v1.80.0', 'v1.69.0'];
+                const tree = resObject.tree.filter(item => item.type === "tree" && !excluded.includes(item.path));
+                const versions = tree.map(item => item.path).sort(sortVersions);
+
+                // Create a list of <li> items for versions
+                versions.forEach((version) => {
+                    const li = document.createElement("li");
+                    li.textContent = version;
+                    li.id = version;
+    
+                    if (window.SYNAPSE_VERSION === version) {
+                        li.classList.add('active');
+                        dropdown.querySelector('span').textContent = version;
+                        dropdown.querySelector('input').value = version;
+                    }
+    
+                    dropdownMenu.appendChild(li);
+                });
+
+                resolve(versions);
+
+            }).catch(ex => {
+                console.error("Failed to fetch version data", ex);
+                reject(ex);
+            })
+        });
+    });
+}
+
+/**
+ * Custom sorting function to sort an array of version strings.
+ *
+ * @param {string} a - The first version string to compare.
+ * @param {string} b - The second version string to compare.
+ * @returns {number} - A negative number if a should come before b, a positive number if b should come before a, or 0 if they are equal.
+ */
+function sortVersions(a, b) {
+    // Put 'develop' and 'latest' at the top
+    if (a === 'develop' || a === 'latest') return -1;
+    if (b === 'develop' || b === 'latest') return 1;
+
+    const versionA = (a.match(/v\d+(\.\d+)+/) || [])[0];
+    const versionB = (b.match(/v\d+(\.\d+)+/) || [])[0];
+
+    return versionB.localeCompare(versionA);
+}
+
+/**
+ * Change the version in a URL path.
+ *
+ * @param {string} url - The original URL to be modified.
+ * @param {string} newVersion - The new version to replace the existing version in the URL.
+ * @returns {string} The updated URL with the new version.
+ */
+function changeVersion(url, newVersion) {
+    const parsedURL = new URL(url);
+    const pathSegments = parsedURL.pathname.split('/');
+  
+    // Modify the version
+    pathSegments[2] = newVersion;
+
+    // Reconstruct the URL
+    parsedURL.pathname = pathSegments.join('/');
+  
+    return parsedURL.href;
+}
\ No newline at end of file
diff --git a/docs/website_files/version.js b/docs/website_files/version.js
new file mode 100644
index 0000000000..8048916372
--- /dev/null
+++ b/docs/website_files/version.js
@@ -0,0 +1 @@
+window.SYNAPSE_VERSION = 'v1.98';