Implement instance API methods (#303)

* Replace deprecated v1 getInstance method with v2 version

* Add missing API methods and entities

* Add old getInstance method back in as deprecated getInstanceV1

---------

Co-authored-by: André Gasser <andre.gasser@protonmail.com>

bigbone-rx/src/main/kotlin/social/bigbone/rx/RxInstanceMethods.kt

@@ -2,7 +2,12 @@ package social.bigbone.rx
 
 import io.reactivex.rxjava3.core.Single
 import social.bigbone.MastodonClient
+import social.bigbone.api.entity.DomainBlock
+import social.bigbone.api.entity.ExtendedDescription
 import social.bigbone.api.entity.Instance
+import social.bigbone.api.entity.InstanceActivity
+import social.bigbone.api.entity.InstanceV1
+import social.bigbone.api.entity.Rule
 import social.bigbone.api.method.InstanceMethods
 
 /**
@@ -14,5 +19,62 @@ class RxInstanceMethods(client: MastodonClient) {
 
     private val instanceMethods = InstanceMethods(client)
 
+    /**
+     * Obtain general information about the server.
+     * @see <a href="https://docs.joinmastodon.org/methods/instance/#v2">Mastodon API documentation: methods/instance/#v2</a>
+     */
     fun getInstance(): Single<Instance> = Single.fromCallable { instanceMethods.getInstance().execute() }
+
+    /**
+     * Obtain general information about the server.
+     * @see <a href="https://docs.joinmastodon.org/methods/instance/#v1">Mastodon API documentation: methods/instance/#v1</a>
+     */
+    @Deprecated(
+        message = "Deprecated since 4.0.0. This method is just kept for backward compatibility.",
+        replaceWith = ReplaceWith("getInstance()"),
+        level = DeprecationLevel.WARNING
+    )
+    fun getInstanceV1(): Single<InstanceV1> = Single.fromCallable { instanceMethods.getInstanceV1().execute() }
+
+    /**
+     * Get the list of connected domains: Domains that this instance is aware of.
+     * @see <a href="https://docs.joinmastodon.org/methods/instance/#peers">Mastodon API documentation: methods/instance/#peers</a>
+     */
+    fun getPeers(): Single<List<String>> = Single.fromCallable {
+        instanceMethods.getPeers().execute()
+    }
+
+    /**
+     * Instance activity over the last 3 months, binned weekly.
+     * @see <a href="https://docs.joinmastodon.org/methods/instance/#activity">Mastodon API documentation: methods/instance/#activity</a>
+     */
+    fun getActivity(): Single<List<InstanceActivity>> = Single.fromCallable {
+        instanceMethods.getActivity().execute()
+    }
+
+    /**
+     * Rules that the users of this service should follow.
+     * @see <a href="https://docs.joinmastodon.org/methods/instance/#rules">Mastodon API documentation: methods/instance/#rules</a>
+     */
+    fun getRules(): Single<List<Rule>> = Single.fromCallable {
+        instanceMethods.getRules().execute()
+    }
+
+    /**
+     * View moderated servers
+     * Obtain a list of domains that have been blocked.
+     * @see <a href="https://docs.joinmastodon.org/methods/instance/#domain_blocks">Mastodon API documentation: methods/instance/#domain_blocks</a>
+     */
+    fun getBlockedDomains(): Single<List<DomainBlock>> = Single.fromCallable {
+        instanceMethods.getBlockedDomains().execute()
+    }
+
+    /**
+     * Obtain an extended description of this server.
+     * @see <a href="https://docs.joinmastodon.org/methods/instance/#extended_description">
+     *     Mastodon API documentation: methods/instance/#extended_description</a>
+     */
+    fun getExtendedDescription(): Single<ExtendedDescription> = Single.fromCallable {
+        instanceMethods.getExtendedDescription().execute()
+    }
 }