Add Foldergram API client, likes set and playlist hand-off

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

3 files changed, 275 insertions, 2 deletions

diff --git a/app/src/main/java/mygram/droid/Api.java b/app/src/main/java/mygram/droid/Api.java
index edc4be1..7cce5b6 100644
--- a/app/src/main/java/mygram/droid/Api.java
+++ b/app/src/main/java/mygram/droid/Api.java
@@ -12,16 +12,84 @@
  * for more details.
  */
 
-
 package mygram.droid;
 
+import android.net.Uri;
+import android.os.Handler;
+import android.os.Looper;
+
+import org.json.JSONArray;
+import org.json.JSONException;
+import org.json.JSONObject;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.net.CookieHandler;
+import java.net.HttpURLConnection;
 import java.net.URI;
+import java.net.URL;
+import java.nio.charset.StandardCharsets;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.Callable;
+import java.util.concurrent.Executor;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.ThreadLocalRandom;
+import java.util.function.Consumer;
 
-/** Foldergram HTTP API. */
+/** Foldergram HTTP API. Calls block; run them through async(). */
 final class Api {
+	static final ExecutorService IO = Executors.newFixedThreadPool(4);
+	private static final int TIMEOUT_MS = 15000;
+	private static final int PAGE = 60;
+
 	private Api() {
 	}
 
+	static final class HttpError extends IOException {
+		final int code;
+
+		HttpError(int code, String body) {
+			super("HTTP " + code + (body.isEmpty() ? "" : ": " + body));
+			this.code = code;
+		}
+	}
+
+	static final class Folder {
+		final String slug, name, avatarUrl;
+		final int count;
+		final long latest;
+
+		Folder(JSONObject o, String base) {
+			slug = o.optString("slug");
+			name = o.optString("name");
+			avatarUrl = resolve(base, Post.str(o, "avatarUrl"));
+			count = o.optInt("imageCount");
+			latest = o.optLong("latestImageMtimeMs");
+		}
+	}
+
+	/** Runs call on the IO pool, then ok or err on the main thread. */
+	static <T> void async(Callable<T> call, Consumer<T> ok, Consumer<Exception> err) {
+		async(IO, call, ok, err);
+	}
+
+	static <T> void async(Executor on, Callable<T> call, Consumer<T> ok, Consumer<Exception> err) {
+		Handler main = new Handler(Looper.getMainLooper());
+		on.execute(() -> {
+			try {
+				T value = call.call();
+				main.post(() -> ok.accept(value));
+			} catch (Exception e) {
+				main.post(() -> err.accept(e));
+			}
+		});
+	}
+
 	/** "192.0.2.10:4141/" or "http://host:4141//" to "http://host:4141". */
 	static String normalize(String url) {
 		String s = url.trim();
@@ -36,4 +104,112 @@ final class Api {
 	static String resolve(String base, String path) {
 		return path == null ? null : URI.create(base + "/").resolve(path).toString();
 	}
+
+	/** One request to base + "/api" + path. Throws HttpError on 4xx/5xx. */
+	static String request(String base, String method, String path, String body, int timeoutMs) throws IOException {
+		HttpURLConnection c = (HttpURLConnection) new URL(base + "/api" + path).openConnection();
+		try {
+			c.setConnectTimeout(timeoutMs);
+			c.setReadTimeout(timeoutMs);
+			c.setRequestMethod(method);
+			// Foldergram rejects mutations without it (requireTrustedMutationRequest).
+			if (!"GET".equals(method))
+				c.setRequestProperty("x-foldergram-intent", "1");
+			if (body != null) {
+				c.setDoOutput(true);
+				c.setRequestProperty("Content-Type", "application/json");
+				try (OutputStream out = c.getOutputStream()) {
+					out.write(body.getBytes(StandardCharsets.UTF_8));
+				}
+			}
+			int code = c.getResponseCode();
+			InputStream in = code < 400 ? c.getInputStream() : c.getErrorStream();
+			String text = in == null ? "" : new String(in.readAllBytes(), StandardCharsets.UTF_8);
+			if (code >= 400)
+				throw new HttpError(code, text);
+			return text;
+		} finally {
+			c.disconnect();
+		}
+	}
+
+	static JSONObject authStatus(String base) throws IOException, JSONException {
+		return new JSONObject(request(base, "GET", "/auth/status", null, 5000));
+	}
+
+	/** Logs in; the session cookie lands in the default CookieManager. */
+	static void login(String base, String password) throws IOException {
+		request(base, "POST", "/auth/login", "{\"password\":" + JSONObject.quote(password) + "}", TIMEOUT_MS);
+	}
+
+	/** A request to the saved server. On 401 logs in again once and retries. */
+	static JSONObject call(String method, String path) throws IOException, JSONException {
+		String base = Prefs.server();
+		try {
+			return new JSONObject(request(base, method, path, null, TIMEOUT_MS));
+		} catch (HttpError e) {
+			if (e.code != 401 || Prefs.password().isEmpty())
+				throw e;
+			login(base, Prefs.password());
+			return new JSONObject(request(base, method, path, null, TIMEOUT_MS));
+		}
+	}
+
+	/** All folders, most recently updated first. */
+	static List<Folder> folders() throws IOException, JSONException {
+		JSONArray items = call("GET", "/folders").getJSONArray("items");
+		List<Folder> out = new ArrayList<>();
+		for (int i = 0; i < items.length(); i++)
+			out.add(new Folder(items.getJSONObject(i), Prefs.server()));
+		out.sort((a, b) -> Long.compare(b.latest, a.latest));
+		return out;
+	}
+
+	/** Every post of a folder, in server order. */
+	static List<Post> folderPosts(String slug) throws IOException, JSONException {
+		List<Post> all = new ArrayList<>();
+		for (int page = 1;; page++) {
+			JSONObject o = call("GET", "/folders/" + Uri.encode(slug) + "/images?limit=" + PAGE + "&page=" + page);
+			all.addAll(Post.list(o, Prefs.server()));
+			if (!o.optBoolean("hasMore"))
+				return all;
+		}
+	}
+
+	/** Up to n random posts of a folder. */
+	// ponytail: samples one random page of 60, so a row never mixes pages; fetch more pages if rows feel repetitive.
+	static List<Post> folderSample(Folder f, int n) throws IOException, JSONException {
+		int pages = Math.max(1, (f.count + PAGE - 1) / PAGE);
+		int page = 1 + ThreadLocalRandom.current().nextInt(pages);
+		String path = "/folders/" + Uri.encode(f.slug) + "/images?limit=" + PAGE + "&page=";
+		List<Post> posts = Post.list(call("GET", path + page), Prefs.server());
+		if (posts.isEmpty() && page > 1) // imageCount counts carousel slides, so pages can run out early
+			posts = Post.list(call("GET", path + 1), Prefs.server());
+		Collections.shuffle(posts);
+		return new ArrayList<>(posts.subList(0, Math.min(n, posts.size())));
+	}
+
+	static List<Post> randomFeed() throws IOException, JSONException {
+		return Post.list(call("GET", "/feed?mode=random&limit=" + PAGE), Prefs.server());
+	}
+
+	static JSONObject reels(int seed, int page) throws IOException, JSONException {
+		return call("GET", "/reels?mode=random&limit=12&seed=" + seed + "&page=" + page);
+	}
+
+	/** Liked posts, newest like first. */
+	static List<Post> likes() throws IOException, JSONException {
+		return Post.list(call("GET", "/likes"), Prefs.server());
+	}
+
+	/** /images/:id/like: older instances lack /posts/:id/like, newer ones keep this alias. */
+	static void setLike(int postId, boolean on) throws IOException, JSONException {
+		call(on ? "POST" : "DELETE", "/images/" + postId + "/like");
+	}
+
+	/** The session cookie for url, for clients that bypass HttpURLConnection. */
+	static Map<String, String> cookieHeaders(String url) throws IOException {
+		List<String> c = CookieHandler.getDefault().get(URI.create(url), Map.of()).get("Cookie");
+		return c == null || c.isEmpty() ? Map.of() : Map.of("Cookie", String.join("; ", c));
+	}
 }
diff --git a/app/src/main/java/mygram/droid/Likes.java b/app/src/main/java/mygram/droid/Likes.java
new file mode 100644
index 0000000..bbe2d51
--- /dev/null
+++ b/app/src/main/java/mygram/droid/Likes.java
@@ -0,0 +1,48 @@
+/*
+ * mygram-droid: Android TV client for Foldergram.
+ * Copyright (C) 2026 Danilo M. <danix@danix.xyz>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published
+ * by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * for more details.
+ */
+
+package mygram.droid;
+
+import org.json.JSONException;
+
+import java.io.IOException;
+import java.util.Set;
+import java.util.concurrent.ConcurrentHashMap;
+
+/** Liked post IDs. Feed items carry no liked flag, so this set drives every heart. */
+final class Likes {
+	private static final Set<Integer> ids = ConcurrentHashMap.newKeySet();
+
+	private Likes() {
+	}
+
+	static void load() throws IOException, JSONException {
+		Set<Integer> fresh = ConcurrentHashMap.newKeySet();
+		for (Post p : Api.likes())
+			fresh.add(p.id);
+		ids.retainAll(fresh);
+		ids.addAll(fresh);
+	}
+
+	static boolean has(int postId) {
+		return ids.contains(postId);
+	}
+
+	static void set(int postId, boolean liked) {
+		if (liked)
+			ids.add(postId);
+		else
+			ids.remove(postId);
+	}
+}
diff --git a/app/src/main/java/mygram/droid/Playlist.java b/app/src/main/java/mygram/droid/Playlist.java
new file mode 100644
index 0000000..98379fb
--- /dev/null
+++ b/app/src/main/java/mygram/droid/Playlist.java
@@ -0,0 +1,49 @@
+/*
+ * mygram-droid: Android TV client for Foldergram.
+ * Copyright (C) 2026 Danilo M. <danix@danix.xyz>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published
+ * by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * for more details.
+ */
+
+package mygram.droid;
+
+import android.content.Context;
+import android.content.Intent;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.concurrent.ThreadLocalRandom;
+
+/** Hands a post list to ViewerActivity; intents cannot carry hundreds of posts. */
+final class Playlist {
+	static List<Post> posts = new ArrayList<>();
+	static int start;
+	/** Non-zero while the viewer plays endless Reels and pages for more. */
+	static int reelsSeed;
+	static int reelsPage;
+
+	private Playlist() {
+	}
+
+	static void open(Context c, List<Post> list, int startIndex) {
+		posts = new ArrayList<>(list);
+		start = startIndex;
+		reelsSeed = 0;
+		c.startActivity(new Intent(c, ViewerActivity.class));
+	}
+
+	static void openReels(Context c) {
+		posts = new ArrayList<>();
+		start = 0;
+		reelsSeed = 1 + ThreadLocalRandom.current().nextInt(1_000_000);
+		reelsPage = 0;
+		c.startActivity(new Intent(c, ViewerActivity.class));
+	}
+}