Add support for server templates

core/src/main/java/discord4j/core/GatewayDiscordClient.java

@@ -27,6 +27,7 @@
 import discord4j.core.event.domain.Event;
 import discord4j.core.object.Invite;
 import discord4j.core.object.Region;
+import discord4j.core.object.Template;
 import discord4j.core.object.entity.*;
 import discord4j.core.object.entity.channel.Channel;
 import discord4j.core.object.entity.channel.GuildChannel;
@@ -249,6 +250,31 @@ public Flux<Region> getRegions() {
                 .map(data -> new Region(this, data));
     }
 
+    /**
+     * Requests to retrieve the guild's templates.
+     *
+     * @return A {@link Flux} that continually emits the guild's {@link Template templates}. If an error is received,
+     * it is emitted through the {@code Flux}.
+     */
+    public Flux<Template> getGuildTemplates(Snowflake guildId) {
+        return getRestClient().getTemplateService()
+                .getTemplates(guildId.asLong())
+                .map(data -> new Template(this, data));
+    }
+
+    /**
+     * Requests to retrieve the template represented by the supplied code.
+     *
+     * @param templateCode The code of the template.
+     * * @return A {@link Mono} where, upon successful completion, emits the {@link Template} as represented by the supplied
+     * * ID. If an error is received, it is emitted through the {@code Mono}.
+     */
+    public Mono<Template> getTemplateByCode(String templateCode) {
+        return getRestClient().getTemplateService()
+                .getTemplate(templateCode)
+                .map(data -> new Template(this, data));
+    }
+
     /**
      * Gets the bot user's ID.
      *

core/src/main/java/discord4j/core/object/Template.java

@@ -0,0 +1,214 @@
+package discord4j.core.object;
+
+import discord4j.common.util.Snowflake;
+import discord4j.core.GatewayDiscordClient;
+import discord4j.core.object.entity.Guild;
+import discord4j.core.object.entity.User;
+import discord4j.core.spec.GuildTemplateEditSpec;
+import discord4j.core.spec.TemplateCreateGuildSpec;
+import discord4j.discordjson.json.SerializedSourceGuildData;
+import discord4j.discordjson.json.TemplateData;
+import reactor.core.publisher.Mono;
+
+import java.time.Instant;
+import java.time.format.DateTimeFormatter;
+import java.util.Objects;
+import java.util.Optional;
+import java.util.function.Consumer;
+
+public class Template implements DiscordObject {
+
+    /** The gateway associated to this object. */
+    private final GatewayDiscordClient gateway;
+
+    /** The raw data as represented by Discord. */
+    private final TemplateData data;
+
+    /** The ID of the guild this template is associated to. */
+    private final long guildId;
+
+    /**
+     * Constructs a {@code Template} with an associated Discord client and data.
+     *
+     * @param gateway The {@link GatewayDiscordClient} associated to this object, must be non-null.
+     * @param data The raw data as represented by Discord, must be non-null.
+     */
+    public Template(final GatewayDiscordClient gateway, final TemplateData data) {
+        this.gateway = Objects.requireNonNull(gateway);
+        this.data = Objects.requireNonNull(data);
+        this.guildId = Snowflake.asLong(data.sourceGuildId());
+    }
+
+    @Override
+    public GatewayDiscordClient getClient() {
+        return this.gateway;
+    }
+
+    /**
+     * Returns this object underlying raw data structure.
+     *
+     * @return an immutable data representation of this object
+     */
+    public TemplateData getData() {
+        return data;
+    }
+
+    /**
+     * Returns the template code (unique ID).
+     *
+     * @return the template code (unique ID)
+     */
+    public final String getCode() {
+        return data.code();
+    }
+
+    /**
+     * Returns the source guild ID.
+     *
+     * @return the guild id
+     */
+    public final Snowflake getGuildId() {
+        return Snowflake.of(guildId);
+    }
+
+    /**
+     * Returns the name of the template.
+     *
+     * @return The template name
+     */
+    public final String getName() {
+        return data.name();
+    }
+
+    /**
+     * Returns the description of the template.
+     *
+     * @return the template description
+     */
+    public final Optional<String> getDescription() {
+        return data.description();
+    }
+
+    /**
+     * Returns the amount of times the template has been used.
+     *
+     * @return the template usage count
+     */
+    public final int getUsageCount() {
+        return data.usageCount();
+    }
+
+    /**
+     * Returns the id of the creator of this template.
+     *
+     * @return the creator id
+     */
+    public final Snowflake getCreatorId() {
+        return Snowflake.of(data.creatorId());
+    }
+
+    /**
+     * Returns the creator of this template.
+     *
+     * @return the creator
+     */
+    public final User getCreator() {
+        return new User(gateway, data.creator());
+    }
+
+    /**
+     * Returns an {@link Instant} when this template was created.
+     *
+     * @return a timestamp when template was last updated
+     */
+    public final Instant getCreatedAt() {
+        return DateTimeFormatter.ISO_OFFSET_DATE_TIME.parse(data.createdAt(), Instant::from);
+    }
+
+    /**
+     * Returns an {@link Instant} when this template was last updated.
+     *
+     * @return a timestamp when template was last updated
+     */
+    public final Instant getUpdatedAt() {
+        return DateTimeFormatter.ISO_OFFSET_DATE_TIME.parse(data.updatedAt(), Instant::from);
+    }
+
+    /**
+     * Gets the guild snapshot of the template.
+     *
+     * @return The guild snapshot.
+     */
+    public final SerializedSourceGuildData getSourceGuild() {
+        return data.serializedSourceGuild();
+    }
+
+    /**
+     * Creates a new guild from a template. Fires Guild Create Gateway event.
+     *
+     * @return the guild object
+     */
+    public final Mono<Guild> createGuild(final Consumer<? super TemplateCreateGuildSpec> spec) {
+        return Mono.defer(
+                () -> {
+                    TemplateCreateGuildSpec mutatedSpec = new TemplateCreateGuildSpec();
+                    spec.accept(mutatedSpec);
+                    return gateway.getRestClient().getTemplateService().createGuild(getCode(),
+                            mutatedSpec.asRequest(), mutatedSpec.getReason());
+                })
+                .map(data -> new Guild(gateway, data));
+    }
+
+    /**
+     * Requests to sync this template with the guild's current state.
+     *
+     * @return a {@link Mono} that, upon subscription, syncs a guild with this template. If an error is received, it
+     * will be emitted through the Mono.
+     */
+    public final Mono<Template> sync() {
+        return sync(guildId);
+    }
+
+    /**
+     * Requests to sync this template with the given guild.
+     *
+     * @param guildId the guild to fetch current state for the template
+     * @return a {@link Mono} that, upon subscription, syncs a guild with this template. If an error is received, it
+     * will be emitted through the Mono.
+     */
+    public final Mono<Template> sync(long guildId) {
+        return gateway.getRestClient().getTemplateService()
+                .syncTemplate(guildId, getCode())
+                .map(data -> new Template(gateway, data));
+    }
+
+    /**
+     * Requests to edit this guild template.
+     *
+     * @param spec A {@link Consumer} that provides a "blank" {@link GuildTemplateEditSpec} to be operated on.
+     * @return A {@link Mono} where, upon successful completion, emits the edited {@link Template}. If an error is
+     * received, it is emitted through the {@code Mono}.
+     */
+    public final Mono<Template> edit(final Consumer<? super GuildTemplateEditSpec> spec) {
+        return Mono.defer(
+                () -> {
+                    GuildTemplateEditSpec mutatedSpec = new GuildTemplateEditSpec();
+                    spec.accept(mutatedSpec);
+                    return gateway.getRestClient().getTemplateService().modifyTemplate(guildId, getCode(),
+                            mutatedSpec.asRequest(), mutatedSpec.getReason());
+                })
+                .map(data -> new Template(gateway, data));
+    }
+
+    /**
+     * Requests to delete this template while optionally specifying a reason.
+     *
+     * @return A {@link Mono} where, upon successful completion, emits the deleted template. If an error is received,
+     * it is emitted through the {@code Mono}.
+     */
+    public final Mono<Template> delete(Snowflake guildId) {
+        return gateway.getRestClient().getTemplateService()
+                .deleteTemplate(guildId.asLong(), getCode())
+                .map(data -> new Template(gateway, data));
+    }
+}

core/src/main/java/discord4j/core/object/entity/Guild.java

@@ -18,10 +18,7 @@
 
 import discord4j.common.util.Snowflake;
 import discord4j.core.GatewayDiscordClient;
-import discord4j.core.object.Ban;
-import discord4j.core.object.ExtendedInvite;
-import discord4j.core.object.Region;
-import discord4j.core.object.VoiceState;
+import discord4j.core.object.*;
 import discord4j.core.object.audit.AuditLogEntry;
 import discord4j.core.object.entity.channel.*;
 import discord4j.core.object.presence.Presence;
@@ -1010,6 +1007,24 @@ public Mono<GuildEmoji> createEmoji(final Consumer<? super GuildEmojiCreateSpec>
                 .map(data -> new GuildEmoji(gateway, data, getId().asLong()));
     }
 
+    /**
+     * Requests to create an template. A guild can only have a single template.
+     *
+     * @param spec A {@link Consumer} that provides a "blank" {@link GuildTemplateCreateSpec} to be operated on.
+     * @return A {@link Mono} where, upon subscription, emits the created {@link Template} on success. If an error is
+     * received, it is emitted through the {@code Mono}.
+     */
+    public Mono<Template> createTemplate(final Consumer<? super GuildTemplateCreateSpec> spec) {
+        return Mono.defer(
+            () -> {
+                GuildTemplateCreateSpec mutatedSpec = new GuildTemplateCreateSpec();
+                spec.accept(mutatedSpec);
+                return gateway.getRestClient().getTemplateService()
+                    .createTemplate(getId().asLong(), mutatedSpec.asRequest(), mutatedSpec.getReason());
+            })
+            .map(data -> new Template(gateway, data));
+    }
+
     /**
      * Requests to create a role.
      *
@@ -1368,6 +1383,18 @@ public Flux<ExtendedInvite> getInvites() {
                 .map(data -> new ExtendedInvite(gateway, data));
     }
 
+    /**
+     * Requests to retrieve the invites of the guild.
+     *
+     * @return A {@link Flux} that continually emits the {@link ExtendedInvite invites} of the guild. If an error is
+     * received, it is emitted through the {@code Flux}.
+     */
+    public Flux<Template> getTemplates() {
+        return gateway.getRestClient().getTemplateService()
+            .getTemplates(getId().asLong())
+            .map(data -> new Template(gateway, data));
+    }
+
     /**
      * Requests to change the bot user's nickname in this guild.
      *

core/src/main/java/discord4j/core/retriever/EntityRetriever.java

@@ -16,16 +16,11 @@
  */
 package discord4j.core.retriever;
 
-import discord4j.core.object.entity.Guild;
-import discord4j.core.object.entity.GuildEmoji;
-import discord4j.core.object.entity.Member;
-import discord4j.core.object.entity.Message;
-import discord4j.core.object.entity.Role;
-import discord4j.core.object.entity.User;
+import discord4j.common.util.Snowflake;
+import discord4j.core.object.entity.*;
 import discord4j.core.object.entity.channel.Channel;
 import discord4j.core.object.entity.channel.GuildChannel;
 import discord4j.core.util.OrderUtil;
-import discord4j.common.util.Snowflake;
 import reactor.core.publisher.Flux;
 import reactor.core.publisher.Mono;
 

core/src/main/java/discord4j/core/retriever/FallbackEntityRetriever.java

@@ -16,15 +16,10 @@
  */
 package discord4j.core.retriever;
 
-import discord4j.core.object.entity.Guild;
-import discord4j.core.object.entity.GuildEmoji;
-import discord4j.core.object.entity.Member;
-import discord4j.core.object.entity.Message;
-import discord4j.core.object.entity.Role;
-import discord4j.core.object.entity.User;
+import discord4j.common.util.Snowflake;
+import discord4j.core.object.entity.*;
 import discord4j.core.object.entity.channel.Channel;
 import discord4j.core.object.entity.channel.GuildChannel;
-import discord4j.common.util.Snowflake;
 import reactor.core.publisher.Flux;
 import reactor.core.publisher.Mono;
 

core/src/main/java/discord4j/core/retriever/RestEntityRetriever.java

@@ -16,6 +16,7 @@
  */
 package discord4j.core.retriever;
 
+import discord4j.common.util.Snowflake;
 import discord4j.core.GatewayDiscordClient;
 import discord4j.core.object.entity.*;
 import discord4j.core.object.entity.channel.Channel;
@@ -24,7 +25,6 @@
 import discord4j.discordjson.json.*;
 import discord4j.rest.RestClient;
 import discord4j.rest.util.PaginationUtil;
-import discord4j.common.util.Snowflake;
 import reactor.core.publisher.Flux;
 import reactor.core.publisher.Mono;
 

core/src/main/java/discord4j/core/retriever/StoreEntityRetriever.java

@@ -89,8 +89,8 @@ public Mono<Role> getRoleById(Snowflake guildId, Snowflake roleId) {
     @Override
     public Mono<User> getUserById(Snowflake userId) {
         return stateView.getUserStore()
-                .find(userId.asLong())
-                .map(data -> new User(gateway, data));
+            .find(userId.asLong())
+            .map(data -> new User(gateway, data));
     }
 
     @Override