Add Chat getters

Add getters for all `Chat` fields nested in `ChatKind`.
`Chat` has a lot of nested enums and so is hard to match on.
The getters help with this.

This patch also corrects type of `slow_mode_delay`: `Option<i32>`` -> `Option<u32>``

src/types/chat.rs

@@ -153,7 +153,7 @@ pub struct PublicChatSupergroup {
     /// unpriviledged user. Returned only from [`GetChat`].
     ///
     /// [`GetChat`]: crate::payloads::GetChat
-    pub slow_mode_delay: Option<i32>,
+    pub slow_mode_delay: Option<u32>,
 
     /// Unique identifier for the linked chat, i.e. the discussion group
     /// identifier for a channel and vice versa. Returned only in [`GetChat`].
@@ -199,6 +199,7 @@ impl Chat {
     pub fn is_private(&self) -> bool {
         matches!(self.kind, ChatKind::Private(_))
     }
+
     pub fn is_group(&self) -> bool {
         matches!(
             self.kind,
@@ -208,6 +209,7 @@ impl Chat {
             })
         )
     }
+
     pub fn is_supergroup(&self) -> bool {
         matches!(
             self.kind,
@@ -217,6 +219,7 @@ impl Chat {
             })
         )
     }
+
     pub fn is_channel(&self) -> bool {
         matches!(
             self.kind,
@@ -232,6 +235,174 @@ impl Chat {
     }
 }
 
+/// Getters
+impl Chat {
+    /// A title, for supergroups, channels and group chats.
+    pub fn title(&self) -> Option<&str> {
+        match &self.kind {
+            ChatKind::Public(this) => this.title.as_deref(),
+            _ => None,
+        }
+    }
+
+    /// A username, for private chats, supergroups and channels if available.
+    pub fn username(&self) -> Option<&str> {
+        match &self.kind {
+            ChatKind::Public(this) => match &this.kind {
+                PublicChatKind::Channel(PublicChatChannel { username, .. })
+                | PublicChatKind::Supergroup(PublicChatSupergroup { username, .. }) => {
+                    username.as_deref()
+                }
+                PublicChatKind::Group(_) => None,
+            },
+            ChatKind::Private(this) => this.username.as_deref(),
+        }
+    }
+
+    /// Unique identifier for the linked chat, i.e. the discussion group
+    /// identifier for a channel and vice versa. Returned only in [`GetChat`].
+    ///
+    /// [`GetChat`]: crate::payloads::GetChat
+    pub fn linked_chat_id(&self) -> Option<i64> {
+        match &self.kind {
+            ChatKind::Public(this) => match &this.kind {
+                PublicChatKind::Channel(PublicChatChannel { linked_chat_id, .. })
+                | PublicChatKind::Supergroup(PublicChatSupergroup { linked_chat_id, .. }) => {
+                    *linked_chat_id
+                }
+                PublicChatKind::Group(_) => None,
+            },
+            _ => None,
+        }
+    }
+
+    /// A default chat member permissions, for groups and supergroups. Returned
+    /// only from [`GetChat`].
+    ///
+    /// [`GetChat`]: crate::payloads::GetChat
+    pub fn permissions(&self) -> Option<ChatPermissions> {
+        if let ChatKind::Public(this) = &self.kind {
+            if let PublicChatKind::Group(PublicChatGroup { permissions })
+            | PublicChatKind::Supergroup(PublicChatSupergroup { permissions, .. }) = &this.kind
+            {
+                return *permissions;
+            }
+        }
+
+        None
+    }
+
+    /// For supergroups, name of group sticker set. Returned only from
+    /// [`GetChat`].
+    ///
+    /// [`GetChat`]: crate::payloads::GetChat
+    pub fn sticker_set_name(&self) -> Option<&str> {
+        if let ChatKind::Public(this) = &self.kind {
+            if let PublicChatKind::Supergroup(this) = &this.kind {
+                return this.sticker_set_name.as_deref();
+            }
+        }
+
+        None
+    }
+
+    /// `true`, if the bot can change the group sticker set. Returned only
+    /// from [`GetChat`].
+    ///
+    /// [`GetChat`]: crate::payloads::GetChat
+    pub fn can_set_sticker_set(&self) -> Option<bool> {
+        if let ChatKind::Public(this) = &self.kind {
+            if let PublicChatKind::Supergroup(this) = &this.kind {
+                return this.can_set_sticker_set;
+            }
+        }
+
+        None
+    }
+
+    /// The minimum allowed delay between consecutive messages sent by each
+    /// unpriviledged user. Returned only from [`GetChat`].
+    ///
+    /// [`GetChat`]: crate::payloads::GetChat
+    pub fn slow_mode_delay(&self) -> Option<u32> {
+        if let ChatKind::Public(this) = &self.kind {
+            if let PublicChatKind::Supergroup(this) = &this.kind {
+                return this.slow_mode_delay;
+            }
+        }
+
+        None
+    }
+
+    /// The location to which the supergroup is connected. Returned only in
+    /// [`GetChat`].
+    ///
+    /// [`GetChat`]: crate::payloads::GetChat
+    pub fn location(&self) -> Option<&ChatLocation> {
+        if let ChatKind::Public(this) = &self.kind {
+            if let PublicChatKind::Supergroup(this) = &this.kind {
+                return this.location.as_ref();
+            }
+        }
+
+        None
+    }
+
+    /// A description, for groups, supergroups and channel chats. Returned
+    /// only in [`GetChat`].
+    ///
+    /// [`GetChat`]: crate::payloads::GetChat
+    pub fn description(&self) -> Option<&str> {
+        match &self.kind {
+            ChatKind::Public(this) => this.description.as_deref(),
+            _ => None,
+        }
+    }
+
+    /// A chat invite link, for groups, supergroups and channel chats. Each
+    /// administrator in a chat generates their own invite links, so the
+    /// bot must first generate the link using
+    /// [`ExportChatInviteLink`]. Returned only in
+    /// [`GetChat`].
+    ///
+    /// [`ExportChatInviteLink`]:
+    /// crate::payloads::ExportChatInviteLink
+    ///
+    /// [`GetChat`]: crate::payloads::GetChat
+    pub fn invite_link(&self) -> Option<&str> {
+        match &self.kind {
+            ChatKind::Public(this) => this.invite_link.as_deref(),
+            _ => None,
+        }
+    }
+
+    /// A first name of the other party in a private chat.
+    pub fn first_name(&self) -> Option<&str> {
+        match &self.kind {
+            ChatKind::Private(this) => this.first_name.as_deref(),
+            _ => None,
+        }
+    }
+
+    /// A last name of the other party in a private chat.
+    pub fn last_name(&self) -> Option<&str> {
+        match &self.kind {
+            ChatKind::Private(this) => this.last_name.as_deref(),
+            _ => None,
+        }
+    }
+
+    /// Bio of the other party in a private chat. Returned only in [`GetChat`].
+    ///
+    /// [`GetChat`]: crate::payloads::GetChat
+    pub fn bio(&self) -> Option<&str> {
+        match &self.kind {
+            ChatKind::Private(this) => this.bio.as_deref(),
+            _ => None,
+        }
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use serde_json::from_str;