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.GuildTemplate;
 import discord4j.core.object.entity.*;
 import discord4j.core.object.entity.channel.Channel;
 import discord4j.core.object.entity.channel.GuildChannel;
@@ -249,6 +250,19 @@ public Flux<Region> getRegions() {
                 .map(data -> new Region(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 GuildTemplate} as represented by the
+     * supplied code. If an error is received, it is emitted through the {@code Mono}.
+     */
+    public Mono<GuildTemplate> getTemplateByCode(String templateCode) {
+        return getRestClient().getTemplateService()
+                .getTemplate(templateCode)
+                .map(data -> new GuildTemplate(this, data));
+    }
+
     /**
      * Gets the bot user's ID.
      *

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

@@ -0,0 +1,226 @@
+/*
+ * This file is part of Discord4J.
+ *
+ * Discord4J is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * Discord4J 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 Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with Discord4J.  If not, see <http://www.gnu.org/licenses/>.
+ */
+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.GuildCreateFromTemplateSpec;
+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;
+
+/**
+ * A Discord Guild Template.
+ *
+ * @see <a href="https://discord.com/developers/docs/resources/template">Template Resource</a>
+ */
+public final class GuildTemplate 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 GuildTemplate} with an associated {@link GatewayDiscordClient} and Discord 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 GuildTemplate(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;
+    }
+
+    /**
+     * Gets the data of the template.
+     *
+     * @return The data of the template.
+     */
+    public TemplateData getData() {
+        return data;
+    }
+
+    /**
+     * Gets the template code (unique ID).
+     *
+     * @return The template code (unique ID).
+     */
+    public String getCode() {
+        return data.code();
+    }
+
+    /**
+     * Gets the ID of the guild this template is associated with.
+     *
+     * @return The source guild ID.
+     */
+    public Snowflake getGuildId() {
+        return Snowflake.of(guildId);
+    }
+
+    /**
+     * Gets the name of the template.
+     *
+     * @return The template name.
+     */
+    public String getName() {
+        return data.name();
+    }
+
+    /**
+     * Gets the description of the template, if present.
+     *
+     * @return The template description.
+     */
+    public Optional<String> getDescription() {
+        return data.description();
+    }
+
+    /**
+     * Gets the number of times the template has been used.
+     *
+     * @return The number of times the template has been used.
+     */
+    public int getUsageCount() {
+        return data.usageCount();
+    }
+
+    /**
+     * Gets the ID of the user who created the template.
+     *
+     * @return The ID of the user who created the template.
+     */
+    public Snowflake getCreatorId() {
+        return Snowflake.of(data.creatorId());
+    }
+
+    /**
+     * Gets the user who created the template.
+     *
+     * @return The user who created the template.
+     */
+    public User getCreator() {
+        return new User(gateway, data.creator());
+    }
+
+    /**
+     * Gets when the template was created.
+     *
+     * @return When the template was created.
+     */
+    public Instant getCreatedAt() {
+        return DateTimeFormatter.ISO_OFFSET_DATE_TIME.parse(data.createdAt(), Instant::from);
+    }
+
+    /**
+     * Gets when the template was last updated.
+     *
+     * @return When the template was last updated.
+     */
+    public 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 SerializedSourceGuildData getSourceGuild() {
+        return data.serializedSourceGuild();
+    }
+
+    /**
+     * Requests to create a new guild from this 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 {@link Guild created guild}. If an error is
+     * received, it is emitted through the {@code Mono}.
+     */
+    public Mono<Guild> createGuild(final Consumer<? super GuildCreateFromTemplateSpec> spec) {
+        return Mono.defer(
+                () -> {
+                    GuildCreateFromTemplateSpec mutatedSpec = new GuildCreateFromTemplateSpec();
+                    spec.accept(mutatedSpec);
+                    return gateway.getRestClient().getTemplateService()
+                            .createGuild(getCode(), mutatedSpec.asRequest());
+                })
+                .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 template with its guild. If an error is received, it
+     * will be emitted through the Mono.
+     */
+    public Mono<GuildTemplate> sync() {
+        return gateway.getRestClient().getTemplateService()
+                .syncTemplate(guildId, getCode())
+                .map(data -> new GuildTemplate(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 GuildTemplate}. If an error is
+     * received, it is emitted through the {@code Mono}.
+     */
+    public Mono<GuildTemplate> 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());
+                })
+                .map(data -> new GuildTemplate(gateway, data));
+    }
+
+    /**
+     * Requests to delete this template.
+     *
+     * @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 Mono<GuildTemplate> delete() {
+        return gateway.getRestClient().getTemplateService()
+                .deleteTemplate(guildId, getCode())
+                .map(data -> new GuildTemplate(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 a template based on this guild.
+     *
+     * @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 GuildTemplate} on success. If an error
+     * is received, it is emitted through the {@code Mono}.
+     */
+    public Mono<GuildTemplate> 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());
+            })
+            .map(data -> new GuildTemplate(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 templates of the guild.
+     *
+     * @return A {@link Flux} that continually emits the {@link GuildTemplate templates} of the guild. If an error is
+     * received, it is emitted through the {@code Flux}.
+     */
+    public Flux<GuildTemplate> getTemplates() {
+        return gateway.getRestClient().getTemplateService()
+            .getTemplates(getId().asLong())
+            .map(data -> new GuildTemplate(gateway, data));
+    }
+
     /**
      * Requests to change the bot user's nickname in this guild.
      *

core/src/main/java/discord4j/core/spec/GuildCreateFromTemplateSpec.java

@@ -0,0 +1,62 @@
+/*
+ * This file is part of Discord4J.
+ *
+ * Discord4J is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * Discord4J 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 Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with Discord4J.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package discord4j.core.spec;
+
+import discord4j.discordjson.json.TemplateCreateGuildRequest;
+import discord4j.discordjson.possible.Possible;
+import discord4j.rest.util.Image;
+
+/**
+ * Spec used to create a guild from a template.
+ *
+ * @see discord4j.core.object.GuildTemplate#createGuild(java.util.function.Consumer)
+ */
+public class GuildCreateFromTemplateSpec implements Spec<TemplateCreateGuildRequest> {
+
+    private String name = null;
+    private Possible<String> icon = Possible.absent();
+
+    /**
+     * Sets the name for the created guild.
+     *
+     * @param name The name of the guild.
+     * @return This spec.
+     */
+    public GuildCreateFromTemplateSpec setName(String name) {
+        this.name = name;
+        return this;
+    }
+
+    /**
+     * Sets the icon for the created guild.
+     *
+     * @param icon The icon of the guild.
+     * @return This spec.
+     */
+    public GuildCreateFromTemplateSpec setIcon(Image icon) {
+        this.icon = Possible.of(icon.getDataUri());
+        return this;
+    }
+
+    @Override
+    public TemplateCreateGuildRequest asRequest() {
+        return TemplateCreateGuildRequest.builder()
+            .name(name)
+            .icon(icon)
+            .build();
+    }
+}