Implement a wiki synchronization system.

This way, we do not have to keep Tiled files for publishing maps,
because users can just pull the maps from the wiki itself and get
notified if any of the maps they already pulled have been
modified.

Author: KockaAdmiralac

.gitignore

@@ -1,3 +1,4 @@
+*.mw-datamaps
 *.png
 *.tiled-session
 node_modules

extensions/includes/api.mjs

@@ -1,3 +1,4 @@
+import { InterwikiDataImpl, MetadataImpl } from './metadata.mjs';
 import { getStringProperty, getWikiUrl } from './util.mjs';
 
 const USER_AGENT = `tiled-datamaps/1.0 (https://github.com/utdrwiki/maps; admin@undertale.wiki) tiled/${tiled.version}`;
@@ -28,13 +29,18 @@ export function getRestUrl(language = 'en') {
  * @param {(value: any|PromiseLike<any>) => void} resolve Promise
  * resolution function
  * @param {(reason: any?) => void} reject Promise rejection function
+ * @param {boolean} isArrayBuffer Whether the request expects a binary response
  * @returns {() => void} Ready state change handler
  */
-const readyStateChange = (xhr, resolve, reject) => () => {
+const readyStateChange = (xhr, resolve, reject, isArrayBuffer = false) => () => {
     if (xhr.readyState === XMLHttpRequest.DONE) {
         if (xhr.status === 200) {
             try {
-                resolve(JSON.parse(xhr.responseText));
+                if (isArrayBuffer) {
+                    resolve(xhr.response);
+                } else {
+                    resolve(JSON.parse(xhr.responseText));
+                }
             } catch (error) {
                 reject(new Error(`Failed to parse response: ${xhr.responseText}`));
             }
@@ -160,3 +166,107 @@ export function edit(title, text, summary, accessToken, language = 'en') {
         return response.edit;
     });
 }
+
+/**
+ * Retrieves maps from the wiki under specific criteria.
+ * @param {object} options Options for retrieving maps
+ * @param {string} language Wiki language
+ * @returns {Promise<DataMap[]>} List of maps on the wiki
+ */
+function getMaps(options, language = 'en') {
+    return httpGet(getApiUrl(language), Object.assign({
+        action: 'query',
+        prop: 'revisions',
+        rvprop: 'ids|content',
+        rvslots: 'main',
+        format: 'json',
+        formatversion: '2',
+    }, options)).then(data => data.query.pages
+        .filter((/** @type {any} */ page) =>
+            page.revisions &&
+            page.revisions.length > 0 &&
+            page.revisions[0].slots &&
+            page.revisions[0].slots.main &&
+            page.revisions[0].slots.main.contentmodel === 'datamap'
+        )
+        .map((/** @type {any} */ page) => {
+            const {slots, revid} = page.revisions[0];
+            const /** @type {DataMap} */ datamap = JSON.parse(slots.main.content);
+            datamap.custom = datamap.custom || new MetadataImpl();
+            datamap.custom.interwiki = datamap.custom.interwiki || {};
+            datamap.custom.interwiki[language] = new InterwikiDataImpl({
+                mapName: page.title.split(':').slice(1).join(':'),
+            });
+            datamap.custom.interwiki[language].revision = revid;
+            return datamap;
+        })
+        .filter((/** @type {DataMap} */ datamap) => !datamap.$fragment)
+    );
+}
+
+/**
+ * Retrieves all maps from the wiki.
+ * @param {string} language Wiki language
+ * @returns {Promise<DataMap[]>} List of maps on the wiki
+ */
+export function getAllMaps(language = 'en') {
+    return getMaps({
+        generator: 'allpages',
+        gapnamespace: '2900',
+        gapfilterredir: 'nonredirects',
+        gaplimit: 'max',
+    }, language);
+}
+
+/**
+ * Retrieves a single map from the wiki.
+ * @param {string} name Map name
+ * @param {string} language Wiki language
+ * @returns {Promise<DataMap>} Specified map from the wiki
+ */
+export function getMap(name, language = 'en') {
+    return getMaps({
+        titles: `Map:${name}`
+    }, language).then(maps => maps[0]);
+}
+
+/**
+ * Returns the URLs of the given map files on the wiki.
+ * @param {string[]} filenames Map file names
+ * @param {string} language Wiki language
+ * @returns {Promise<string[]>} URLs of the given map files on the wiki
+ */
+export function getFileUrls(filenames, language = 'en') {
+    return httpGet(getApiUrl(language), {
+        action: 'query',
+        titles: filenames.map(name => `File:${name}`).join('|'),
+        prop: 'imageinfo',
+        iiprop: 'url',
+        format: 'json',
+        formatversion: '2'
+    }).then(data => filenames.map(filename => data.query.pages
+        .find((/** @type {any} */ page) => page.title === `File:${
+            data.query.normalized
+                ?.find((/** @type {any} */ n) => n.from === filename)
+                ?.to ||
+            filename
+        }`)
+        ?.imageinfo[0].url)
+        .filter(Boolean));
+}
+
+/**
+ * Downloads a file from a URL and returns it as an ArrayBuffer.
+ * @param {string} url URL to download the file from
+ * @returns {Promise<ArrayBuffer>} Downloaded file data
+ */
+export function downloadFile(url) {
+    return new Promise((resolve, reject) => {
+        const xhr = new XMLHttpRequest();
+        xhr.open('GET', url, true);
+        xhr.responseType = 'arraybuffer';
+        xhr.onreadystatechange = readyStateChange(xhr, resolve, reject, true);
+        xhr.setRequestHeader('User-Agent', USER_AGENT);
+        xhr.send();
+    });
+}