Add functions to reorder a guild's channels

Add `http::edit_guild_channel_positions`, `Guild::reorder_channels`, and
`GuildId::reorder_channels`.

3 files changed, 44 insertions, 0 deletions

diff --git a/src/http/mod.rs b/src/http/mod.rs
index 8abed78..b1a8379 100644
--- a/src/http/mod.rs
+++ b/src/http/mod.rs
@@ -708,6 +708,22 @@ pub fn edit_guild(guild_id: u64, map: &JsonMap) -> Result<PartialGuild> {
         .map_err(From::from)
 }
 
+/// Edits the positions of a guild's channels.
+pub fn edit_guild_channel_positions(guild_id: u64, value: &Value)
+    -> Result<()> {
+    let body = serde_json::to_string(value)?;
+
+    verify(
+        204,
+        request!(
+            Route::GuildsIdChannels(guild_id),
+            patch(body),
+            "/guilds/{}/channels",
+            guild_id,
+        ),
+    )
+}
+
 /// Edits a [`Guild`]'s embed setting.
 ///
 /// [`Guild`]: ../model/struct.Guild.html
diff --git a/src/model/guild/guild_id.rs b/src/model/guild/guild_id.rs
index a86b6a9..3cce275 100644
--- a/src/model/guild/guild_id.rs
+++ b/src/model/guild/guild_id.rs
@@ -433,6 +433,24 @@ impl GuildId {
         http::get_guild_prune_count(self.0, &map)
     }
 
+    /// Re-orders the channels of the guild.
+    ///
+    /// Accepts an iterator of a tuple of the channel ID to modify and its new
+    /// position.
+    ///
+    /// Although not required, you should specify all channels' positions,
+    /// regardless of whether they were updated. Otherwise, positioning can
+    /// sometimes get weird.
+    pub fn reorder_channels<It>(&self, channels: It) -> Result<()>
+        where It: IntoIterator<Item = (ChannelId, u64)> {
+        let items = channels.into_iter().map(|(id, pos)| json!({
+            "id": id,
+            "position": pos,
+        })).collect();
+
+        http::edit_guild_channel_positions(self.0, &Value::Array(items))
+    }
+
     /// Returns the Id of the shard associated with the guild.
     ///
     /// When the cache is enabled this will automatically retrieve the total
diff --git a/src/model/guild/mod.rs b/src/model/guild/mod.rs
index 9d576ea..9a51956 100644
--- a/src/model/guild/mod.rs
+++ b/src/model/guild/mod.rs
@@ -1343,6 +1343,16 @@ impl Guild {
         self.id.prune_count(days)
     }
 
+    /// Re-orders the channels of the guild.
+    ///
+    /// Although not required, you should specify all channels' positions,
+    /// regardless of whether they were updated. Otherwise, positioning can
+    /// sometimes get weird.
+    pub fn reorder_channels<It>(&self, channels: It) -> Result<()>
+        where It: IntoIterator<Item = (ChannelId, u64)> {
+        self.id.reorder_channels(channels)
+    }
+
     /// Returns the Id of the shard associated with the guild.
     ///
     /// When the cache is enabled this will automatically retrieve the total