//! Models relating to Discord channels.

#[cfg(feature = "model")]
use std::fmt::Display;
#[cfg(all(feature = "cache", feature = "model"))]
use std::fmt::Write;

#[cfg(all(feature = "model", feature = "utils"))]
use crate::builder::{Builder, CreateAllowedMentions, CreateMessage, EditMessage};
#[cfg(all(feature = "cache", feature = "model"))]
use crate::cache::{Cache, GuildRef};
#[cfg(feature = "collector")]
use crate::collector::{
    ComponentInteractionCollector,
    ModalInteractionCollector,
    ReactionCollector,
};
#[cfg(feature = "model")]
use crate::constants;
#[cfg(feature = "collector")]
use crate::gateway::ShardMessenger;
#[cfg(feature = "model")]
use crate::http::{CacheHttp, Http};
use crate::model::prelude::*;
use crate::model::utils::StrOrInt;
#[cfg(all(feature = "model", feature = "cache"))]
use crate::utils;

/// A representation of a message over a guild's text channel, a group, or a private channel.
///
/// [Discord docs](https://discord.com/developers/docs/resources/channel#message-object) with some
/// [extra fields](https://discord.com/developers/docs/topics/gateway-events#message-create-message-create-extra-fields).
#[cfg_attr(feature = "typesize", derive(typesize::derive::TypeSize))]
#[derive(Clone, Debug, Default, Deserialize, Serialize)]
#[non_exhaustive]
pub struct Message {
    /// The unique Id of the message. Can be used to calculate the creation date of the message.
    pub id: MessageId,
    /// The Id of the [`Channel`] that the message was sent to.
    pub channel_id: ChannelId,
    /// The user that sent the message.
    pub author: User,
    /// The content of the message.
    pub content: String,
    /// Initial message creation timestamp, calculated from its Id.
    pub timestamp: Timestamp,
    /// The timestamp of the last time the message was updated, if it was.
    pub edited_timestamp: Option<Timestamp>,
    /// Indicator of whether the command is to be played back via text-to-speech.
    ///
    /// In the client, this is done via the `/tts` slash command.
    pub tts: bool,
    /// Indicator of whether the message mentions everyone.
    pub mention_everyone: bool,
    /// Array of users mentioned in the message.
    pub mentions: Vec<User>,
    /// Array of [`Role`]s' Ids mentioned in the message.
    pub mention_roles: Vec<RoleId>,
    /// Channels specifically mentioned in this message.
    ///
    /// **Note**: Not all channel mentions in a message will appear in [`Self::mention_channels`].
    /// Only textual channels that are visible to everyone in a lurkable guild will ever be
    /// included.
    ///
    /// A lurkable guild is one that allows users to read public channels in a server without
    /// actually joining the server. It also allows users to look at these channels without being
    /// logged in to Discord.
    ///
    /// Only crossposted messages (via Channel Following) currently include
    /// [`Self::mention_channels`] at all. If no mentions in the message meet these requirements,
    /// this field will not be sent.
    ///
    /// [Refer to Discord's documentation for more information][discord-docs].
    ///
    /// [discord-docs]: https://discord.com/developers/docs/resources/channel#message-object
    #[serde(default = "Vec::new")]
    pub mention_channels: Vec<ChannelMention>,
    /// An vector of the files attached to a message.
    pub attachments: Vec<Attachment>,
    /// Array of embeds sent with the message.
    pub embeds: Vec<Embed>,
    /// Array of reactions performed on the message.
    #[serde(default)]
    pub reactions: Vec<MessageReaction>,
    /// Non-repeating number used for ensuring message order.
    #[serde(default)]
    pub nonce: Option<Nonce>,
    /// Indicator of whether the message is pinned.
    pub pinned: bool,
    /// The Id of the webhook that sent this message, if one did.
    pub webhook_id: Option<WebhookId>,
    /// Indicator of the type of message this is, i.e. whether it is a regular message or a system
    /// message.
    #[serde(rename = "type")]
    pub kind: MessageType,
    /// Sent with Rich Presence-related chat embeds.
    pub activity: Option<MessageActivity>,
    /// Sent with Rich Presence-related chat embeds.
    pub application: Option<MessageApplication>,
    /// If the message is an Interaction or application-owned webhook, this is the id of the
    /// application.
    pub application_id: Option<ApplicationId>,
    /// Reference data sent with crossposted messages.
    pub message_reference: Option<MessageReference>,
    /// Bit flags describing extra features of the message.
    pub flags: Option<MessageFlags>,
    /// The message that was replied to using this message.
    pub referenced_message: Option<Box<Message>>, // Boxed to avoid recursion
    /// Sent if the message is a response to an [`Interaction`].
    ///
    /// [`Interaction`]: crate::model::application::Interaction
    pub interaction: Option<Box<MessageInteraction>>,
    /// The thread that was started from this message, includes thread member object.
    pub thread: Option<GuildChannel>,
    /// The components of this message
    #[serde(default)]
    pub components: Vec<ActionRow>,
    /// Array of message sticker item objects.
    #[serde(default)]
    pub sticker_items: Vec<StickerItem>,
    /// A generally increasing integer (there may be gaps or duplicates) that represents the
    /// approximate position of the message in a thread, it can be used to estimate the relative
    /// position of the message in a thread in company with total_message_sent on parent thread.
    pub position: Option<u64>,
    /// Data of the role subscription purchase or renewal that prompted this
    /// [`MessageType::RoleSubscriptionPurchase`] message.
    pub role_subscription_data: Option<RoleSubscriptionData>,
    // Field omitted: stickers (it's deprecated by Discord)
    /// The Id of the [`Guild`] that the message was sent in. This value will only be present if
    /// this message was received over the gateway, therefore **do not use this to check if message
    /// is in DMs**, it is not a reliable method.
    // TODO: maybe introduce an `enum MessageLocation { Dm, Guild(GuildId) }` and store
    // `Option<MessageLocation` here. Instead of None being ambiguous (is it in DMs? Or do we just
    // not know because HTTP retrieved Messages don't have guild ID?), we'd set
    // Some(MessageLocation::Dm) in gateway and None in HTTP.
    pub guild_id: Option<GuildId>,
    /// A partial amount of data about the user's member data
    ///
    /// Only present in [`MessageCreateEvent`].
    pub member: Option<Box<PartialMember>>,
}

#[cfg(feature = "model")]
impl Message {
    /// Crossposts this message.
    ///
    /// Requires either to be the message author or to have manage [Manage Messages] permissions on
    /// this channel.
    ///
    /// **Note**: Only available on news channels.
    ///
    /// # Errors
    ///
    /// If the `cache` is enabled, returns a [`ModelError::InvalidPermissions`] if the current user
    /// does not have the required permissions.
    ///
    /// Returns a [`ModelError::MessageAlreadyCrossposted`] if the message has already been
    /// crossposted.
    ///
    /// Returns a [`ModelError::CannotCrosspostMessage`] if the message cannot be crossposted.
    ///
    /// [Manage Messages]: Permissions::MANAGE_MESSAGES
    pub async fn crosspost(&self, cache_http: impl CacheHttp) -> Result<Message> {
        #[cfg(feature = "cache")]
        {
            if let Some(cache) = cache_http.cache() {
                if self.author.id != cache.current_user().id && self.guild_id.is_some() {
                    utils::user_has_perms_cache(
                        cache,
                        self.channel_id,
                        Permissions::MANAGE_MESSAGES,
                    )?;
                }
            }
        }

        if let Some(flags) = self.flags {
            if flags.contains(MessageFlags::CROSSPOSTED) {
                return Err(Error::Model(ModelError::MessageAlreadyCrossposted));
            } else if flags.contains(MessageFlags::IS_CROSSPOST)
                || self.kind != MessageType::Regular
            {
                return Err(Error::Model(ModelError::CannotCrosspostMessage));
            }
        }

        self.channel_id.crosspost(cache_http.http(), self.id).await
    }

    /// First attempts to find a [`Channel`] by its Id in the cache, upon failure requests it via
    /// the REST API.
    ///
    /// **Note**: If the `cache`-feature is enabled permissions will be checked and upon owning the
    /// required permissions the HTTP-request will be issued.
    ///
    /// # Errors
    ///
    /// Can return an error if the HTTP request fails.
    #[inline]
    pub async fn channel(&self, cache_http: impl CacheHttp) -> Result<Channel> {
        self.channel_id.to_channel(cache_http).await
    }

    /// A util function for determining whether this message was sent by someone else, or the bot.
    #[cfg(feature = "cache")]
    pub fn is_own(&self, cache: impl AsRef<Cache>) -> bool {
        self.author.id == cache.as_ref().current_user().id
    }

    /// Deletes the message.
    ///
    /// **Note**: The logged in user must either be the author of the message or have the [Manage
    /// Messages] permission.
    ///
    /// # Errors
    ///
    /// If the `cache` feature is enabled, then returns a [`ModelError::InvalidPermissions`] if the
    /// current user does not have the required permissions.
    ///
    /// [Manage Messages]: Permissions::MANAGE_MESSAGES
    pub async fn delete(&self, cache_http: impl CacheHttp) -> Result<()> {
        #[cfg(feature = "cache")]
        {
            if let Some(cache) = cache_http.cache() {
                if self.author.id != cache.current_user().id {
                    utils::user_has_perms_cache(
                        cache,
                        self.channel_id,
                        Permissions::MANAGE_MESSAGES,
                    )?;
                }
            }
        }

        self.channel_id.delete_message(cache_http.http(), self.id).await
    }

    /// Deletes all of the [`Reaction`]s associated with the message.
    ///
    /// **Note**: Requires the [Manage Messages] permission.
    ///
    /// # Errors
    ///
    /// If the `cache` feature is enabled, then returns a [`ModelError::InvalidPermissions`] if the
    /// current user does not have the required permissions.
    ///
    /// [Manage Messages]: Permissions::MANAGE_MESSAGES
    pub async fn delete_reactions(&self, cache_http: impl CacheHttp) -> Result<()> {
        #[cfg(feature = "cache")]
        {
            if let Some(cache) = cache_http.cache() {
                utils::user_has_perms_cache(cache, self.channel_id, Permissions::MANAGE_MESSAGES)?;
            }
        }

        self.channel_id.delete_reactions(cache_http.http(), self.id).await
    }

    /// Deletes the given [`Reaction`] from the message.
    ///
    /// **Note**: Requires the [Manage Messages] permission, _if_ the current user did not perform
    /// the reaction.
    ///
    /// # Errors
    ///
    /// Returns [`Error::Http`] if the current user did not perform the reaction, or lacks
    /// permission.
    ///
    /// [Manage Messages]: Permissions::MANAGE_MESSAGES
    #[inline]
    pub async fn delete_reaction(
        &self,
        http: impl AsRef<Http>,
        user_id: Option<UserId>,
        reaction_type: impl Into<ReactionType>,
    ) -> Result<()> {
        self.channel_id.delete_reaction(http, self.id, user_id, reaction_type).await
    }

    /// Deletes all of the [`Reaction`]s of a given emoji associated with the message.
    ///
    /// **Note**: Requires the [Manage Messages] permission.
    ///
    /// # Errors
    ///
    /// If the `cache` feature is enabled, then returns a [`ModelError::InvalidPermissions`] if the
    /// current user does not have the required permissions.
    ///
    /// [Manage Messages]: Permissions::MANAGE_MESSAGES
    pub async fn delete_reaction_emoji(
        &self,
        cache_http: impl CacheHttp,
        reaction_type: impl Into<ReactionType>,
    ) -> Result<()> {
        #[cfg(feature = "cache")]
        {
            if let Some(cache) = cache_http.cache() {
                utils::user_has_perms_cache(cache, self.channel_id, Permissions::MANAGE_MESSAGES)?;
            }
        }

        cache_http
            .http()
            .as_ref()
            .delete_message_reaction_emoji(self.channel_id, self.id, &reaction_type.into())
            .await
    }

    /// Edits this message, replacing the original content with new content.
    ///
    /// Message editing preserves all unchanged message data, with some exceptions for embeds and
    /// attachments.
    ///
    /// **Note**: In most cases requires that the current user be the author of the message.
    ///
    /// Refer to the documentation for [`EditMessage`] for information regarding content
    /// restrictions and requirements.
    ///
    /// # Examples
    ///
    /// Edit a message with new content:
    ///
    /// ```rust,no_run
    /// # use serenity::builder::EditMessage;
    /// # use serenity::model::channel::Message;
    /// # use serenity::model::id::ChannelId;
    /// # use serenity::http::Http;
    /// #
    /// # async fn run() -> Result<(), Box<dyn std::error::Error>> {
    /// # let http: Http = unimplemented!();
    /// # let mut message: Message = unimplemented!();
    /// // assuming a `message` has already been bound
    /// let builder = EditMessage::new().content("new content");
    /// message.edit(&http, builder).await?;
    /// # Ok(())
    /// # }
    /// ```
    ///
    /// # Errors
    ///
    /// If the `cache` is enabled, returns a [`ModelError::InvalidUser`] if the current user is not
    /// the author. Otherwise returns [`Error::Http`] if the user lacks permission, as well as if
    /// invalid data is given.
    ///
    /// Returns a [`ModelError::MessageTooLong`] if the message contents are too long.
    ///
    /// [Manage Messages]: Permissions::MANAGE_MESSAGES
    pub async fn edit(&mut self, cache_http: impl CacheHttp, builder: EditMessage) -> Result<()> {
        if let Some(flags) = self.flags {
            if flags.contains(MessageFlags::IS_VOICE_MESSAGE) {
                return Err(Error::Model(ModelError::CannotEditVoiceMessage));
            }
        }

        *self =
            builder.execute(cache_http, (self.channel_id, self.id, Some(self.author.id))).await?;
        Ok(())
    }

    /// Returns message content, but with user and role mentions replaced with
    /// names and everyone/here mentions cancelled.
    #[cfg(feature = "cache")]
    pub fn content_safe(&self, cache: impl AsRef<Cache>) -> String {
        let mut result = self.content.clone();

        // First replace all user mentions.
        for u in &self.mentions {
            let mut at_distinct = String::with_capacity(38);
            at_distinct.push('@');
            at_distinct.push_str(&u.name);
            if let Some(discriminator) = u.discriminator {
                at_distinct.push('#');
                write!(at_distinct, "{:04}", discriminator.get()).unwrap();
            }

            let mut m = u.mention().to_string();
            // Check whether we're replacing a nickname mention or a normal mention.
            // `UserId::mention` returns a normal mention. If it isn't present in the message, it's
            // a nickname mention.
            if !result.contains(&m) {
                m.insert(2, '!');
            }

            result = result.replace(&m, &at_distinct);
        }

        // Then replace all role mentions.
        if let Some(guild_id) = self.guild_id {
            for id in &self.mention_roles {
                let mention = id.mention().to_string();

                if let Some(guild) = cache.as_ref().guild(guild_id) {
                    if let Some(role) = guild.roles.get(id) {
                        result = result.replace(&mention, &format!("@{}", role.name));
                        continue;
                    }
                }

                result = result.replace(&mention, "@deleted-role");
            }
        }

        // And finally replace everyone and here mentions.
        result.replace("@everyone", "@\u{200B}everyone").replace("@here", "@\u{200B}here")
    }

    /// Gets the list of [`User`]s who have reacted to a [`Message`] with a certain [`Emoji`].
    ///
    /// The default `limit` is `50` - specify otherwise to receive a different maximum number of
    /// users. The maximum that may be retrieve at a time is `100`, if a greater number is provided
    /// then it is automatically reduced.
    ///
    /// The optional `after` attribute is to retrieve the users after a certain user. This is
    /// useful for pagination.
    ///
    /// **Note**: Requires the [Read Message History] permission.
    ///
    /// **Note**: If the passed reaction_type is a custom guild emoji, it must contain the name.
    /// So, [`Emoji`] or [`EmojiIdentifier`] will always work, [`ReactionType`] only if
    /// [`ReactionType::Custom::name`] is Some, and **[`EmojiId`] will never work**.
    ///
    /// # Errors
    ///
    /// Returns [`Error::Http`] if the current user lacks permission.
    ///
    /// [Read Message History]: Permissions::READ_MESSAGE_HISTORY
    #[inline]
    pub async fn reaction_users(
        &self,
        http: impl AsRef<Http>,
        reaction_type: impl Into<ReactionType>,
        limit: Option<u8>,
        after: impl Into<Option<UserId>>,
    ) -> Result<Vec<User>> {
        self.channel_id.reaction_users(http, self.id, reaction_type, limit, after).await
    }

    /// Returns the associated [`Guild`] for the message if one is in the cache.
    ///
    /// Returns [`None`] if the guild's Id could not be found via [`Self::guild_id`] or if the
    /// Guild itself is not cached.
    ///
    /// Requires the `cache` feature be enabled.
    #[cfg(feature = "cache")]
    pub fn guild<'a>(&self, cache: &'a Cache) -> Option<GuildRef<'a>> {
        cache.guild(self.guild_id?)
    }

    /// True if message was sent using direct messages.
    ///
    /// **Only use this for messages from the gateway (event handler)!** Not for returned Message
    /// objects from HTTP requests, like [`ChannelId::send_message`], because [`Self::guild_id`] is
    /// never set for those, which this method relies on.
    #[inline]
    #[must_use]
    pub fn is_private(&self) -> bool {
        self.guild_id.is_none()
    }

    /// Retrieves a clone of the author's Member instance, if this message was sent in a guild.
    ///
    /// If the instance cannot be found in the cache, or the `cache` feature is disabled, a HTTP
    /// request is performed to retrieve it from Discord's API.
    ///
    /// # Errors
    ///
    /// [`ModelError::ItemMissing`] is returned if [`Self::guild_id`] is [`None`].
    pub async fn member(&self, cache_http: impl CacheHttp) -> Result<Member> {
        match self.guild_id {
            Some(guild_id) => guild_id.member(cache_http, self.author.id).await,
            None => Err(Error::Model(ModelError::ItemMissing)),
        }
    }

    /// Checks the length of a message to ensure that it is within Discord's maximum length limit.
    ///
    /// Returns [`None`] if the message is within the limit, otherwise returns [`Some`] with an
    /// inner value of how many unicode code points the message is over.
    #[must_use]
    pub fn overflow_length(content: &str) -> Option<usize> {
        crate::builder::check_overflow(content.chars().count(), constants::MESSAGE_CODE_LIMIT).err()
    }

    /// Pins this message to its channel.
    ///
    /// **Note**: Requires the [Manage Messages] permission.
    ///
    /// # Errors
    ///
    /// If the `cache` is enabled, returns a [`ModelError::InvalidPermissions`] if the current user
    /// does not have the required permissions.
    ///
    /// [Manage Messages]: Permissions::MANAGE_MESSAGES
    pub async fn pin(&self, cache_http: impl CacheHttp) -> Result<()> {
        #[cfg(feature = "cache")]
        {
            if let Some(cache) = cache_http.cache() {
                if self.guild_id.is_some() {
                    utils::user_has_perms_cache(
                        cache,
                        self.channel_id,
                        Permissions::MANAGE_MESSAGES,
                    )?;
                }
            }
        }

        self.channel_id.pin(cache_http.http(), self.id).await
    }

    /// React to the message with a custom [`Emoji`] or unicode character.
    ///
    /// **Note**: Requires the [Add Reactions] permission.
    ///
    /// # Errors
    ///
    /// If the `cache` is enabled, returns a [`ModelError::InvalidPermissions`] if the current user
    /// does not have the required [permissions].
    ///
    /// [Add Reactions]: Permissions::ADD_REACTIONS
    /// [permissions]: crate::model::permissions
    #[inline]
    pub async fn react(
        &self,
        cache_http: impl CacheHttp,
        reaction_type: impl Into<ReactionType>,
    ) -> Result<Reaction> {
        self._react(cache_http, reaction_type.into()).await
    }

    async fn _react(
        &self,
        cache_http: impl CacheHttp,
        reaction_type: ReactionType,
    ) -> Result<Reaction> {
        #[cfg_attr(not(feature = "cache"), allow(unused_mut))]
        let mut user_id = None;

        #[cfg(feature = "cache")]
        {
            if let Some(cache) = cache_http.cache() {
                if self.guild_id.is_some() {
                    utils::user_has_perms_cache(
                        cache,
                        self.channel_id,
                        Permissions::ADD_REACTIONS,
                    )?;
                }

                user_id = Some(cache.current_user().id);
            }
        }

        cache_http.http().create_reaction(self.channel_id, self.id, &reaction_type).await?;

        Ok(Reaction {
            channel_id: self.channel_id,
            emoji: reaction_type,
            message_id: self.id,
            user_id,
            guild_id: self.guild_id,
            member: self.member.as_deref().map(|member| member.clone().into()),
        })
    }

    /// Uses Discord's inline reply to a user without pinging them.
    ///
    /// User mentions are generally around 20 or 21 characters long.
    ///
    /// **Note**: Requires the [Send Messages] permission.
    ///
    /// **Note**: Message contents must be under 2000 unicode code points.
    ///
    /// # Errors
    ///
    /// If the `cache` is enabled, returns a [`ModelError::InvalidPermissions`] if the current user
    /// does not have the required permissions.
    ///
    /// Returns a [`ModelError::MessageTooLong`] if the content of the message is over the above
    /// limit, containing the number of unicode code points over the limit.
    ///
    /// [Send Messages]: Permissions::SEND_MESSAGES
    #[inline]
    pub async fn reply(
        &self,
        cache_http: impl CacheHttp,
        content: impl Into<String>,
    ) -> Result<Message> {
        self._reply(cache_http, content, Some(false)).await
    }

    /// Uses Discord's inline reply to a user with a ping.
    ///
    /// **Note**: Requires the [Send Messages] permission.
    ///
    /// **Note**: Message contents must be under 2000 unicode code points.
    ///
    /// # Errors
    ///
    /// If the `cache` is enabled, returns a [`ModelError::InvalidPermissions`] if the current user
    /// does not have the required permissions.
    ///
    /// Returns a [`ModelError::MessageTooLong`] if the content of the message is over the above
    /// limit, containing the number of unicode code points over the limit.
    ///
    /// [Send Messages]: Permissions::SEND_MESSAGES
    #[inline]
    pub async fn reply_ping(
        &self,
        cache_http: impl CacheHttp,
        content: impl Into<String>,
    ) -> Result<Message> {
        self._reply(cache_http, content, Some(true)).await
    }

    /// Replies to the user, mentioning them prior to the content in the form of: `@<USER_ID>
    /// YOUR_CONTENT`.
    ///
    /// User mentions are generally around 20 or 21 characters long.
    ///
    /// **Note**: Requires the [Send Messages] permission.
    ///
    /// **Note**: Message contents must be under 2000 unicode code points.
    ///
    /// # Errors
    ///
    /// If the `cache` is enabled, returns a [`ModelError::InvalidPermissions`] if the current user
    /// does not have the required permissions.
    ///
    /// Returns a [`ModelError::MessageTooLong`] if the content of the message is over the above
    /// limit, containing the number of unicode code points over the limit.
    ///
    /// [Send Messages]: Permissions::SEND_MESSAGES
    #[inline]
    pub async fn reply_mention(
        &self,
        cache_http: impl CacheHttp,
        content: impl Display,
    ) -> Result<Message> {
        self._reply(cache_http, format!("{} {content}", self.author.mention()), None).await
    }

    /// `inlined` decides whether this reply is inlined and whether it pings.
    async fn _reply(
        &self,
        cache_http: impl CacheHttp,
        content: impl Into<String>,
        inlined: Option<bool>,
    ) -> Result<Message> {
        #[cfg(feature = "cache")]
        {
            if let Some(cache) = cache_http.cache() {
                if self.guild_id.is_some() {
                    utils::user_has_perms_cache(
                        cache,
                        self.channel_id,
                        Permissions::SEND_MESSAGES,
                    )?;
                }
            }
        }

        let mut builder = CreateMessage::new().content(content);
        if let Some(ping_user) = inlined {
            let allowed_mentions = CreateAllowedMentions::new()
                .replied_user(ping_user)
                // By providing allowed_mentions, Discord disabled _all_ pings by default so we
                // need to re-enable them
                .everyone(true)
                .all_users(true)
                .all_roles(true);
            builder = builder.reference_message(self).allowed_mentions(allowed_mentions);
        }
        self.channel_id.send_message(cache_http, builder).await
    }

    /// Checks whether the message mentions passed [`UserId`].
    #[inline]
    pub fn mentions_user_id(&self, id: impl Into<UserId>) -> bool {
        let id = id.into();
        self.mentions.iter().any(|mentioned_user| mentioned_user.id == id)
    }

    /// Checks whether the message mentions passed [`User`].
    #[inline]
    #[must_use]
    pub fn mentions_user(&self, user: &User) -> bool {
        self.mentions_user_id(user.id)
    }

    /// Checks whether the message mentions the current user.
    ///
    /// # Errors
    ///
    /// May return [`Error::Http`] if the `cache` feature is not enabled, or if the cache is
    /// otherwise unavailable.
    pub async fn mentions_me(&self, cache_http: impl CacheHttp) -> Result<bool> {
        #[cfg(feature = "cache")]
        {
            if let Some(cache) = cache_http.cache() {
                return Ok(self.mentions_user_id(cache.current_user().id));
            }
        }

        let current_user = cache_http.http().get_current_user().await?;
        Ok(self.mentions_user_id(current_user.id))
    }

    /// Unpins the message from its channel.
    ///
    /// **Note**: Requires the [Manage Messages] permission.
    ///
    /// # Errors
    ///
    /// If the `cache` is enabled, returns a [`ModelError::InvalidPermissions`] if the current user
    /// does not have the required permissions.
    ///
    /// [Manage Messages]: Permissions::MANAGE_MESSAGES
    pub async fn unpin(&self, cache_http: impl CacheHttp) -> Result<()> {
        #[cfg(feature = "cache")]
        {
            if let Some(cache) = cache_http.cache() {
                if self.guild_id.is_some() {
                    utils::user_has_perms_cache(
                        cache,
                        self.channel_id,
                        Permissions::MANAGE_MESSAGES,
                    )?;
                }
            }
        }

        cache_http.http().unpin_message(self.channel_id, self.id, None).await
    }

    /// Tries to return author's nickname in the current channel's guild.
    ///
    /// Refer to [`User::nick_in()`] inside and [`None`] outside of a guild.
    #[inline]
    pub async fn author_nick(&self, cache_http: impl CacheHttp) -> Option<String> {
        self.author.nick_in(cache_http, self.guild_id?).await
    }

    /// Returns a link referencing this message. When clicked, users will jump to the message. The
    /// link will be valid for messages in either private channels or guilds.
    #[inline]
    #[must_use]
    pub fn link(&self) -> String {
        self.id.link(self.channel_id, self.guild_id)
    }

    /// Same as [`Self::link`] but tries to find the [`GuildId`] if Discord does not provide it.
    ///
    /// [`guild_id`]: Self::guild_id
    #[inline]
    pub async fn link_ensured(&self, cache_http: impl CacheHttp) -> String {
        self.id.link_ensured(cache_http, self.channel_id, self.guild_id).await
    }

    /// Returns a builder which can be awaited to obtain a reaction or stream of reactions on this
    /// message.
    #[cfg(feature = "collector")]
    pub fn await_reaction(&self, shard_messenger: impl AsRef<ShardMessenger>) -> ReactionCollector {
        ReactionCollector::new(shard_messenger).message_id(self.id)
    }

    /// Same as [`Self::await_reaction`].
    #[cfg(feature = "collector")]
    pub fn await_reactions(
        &self,
        shard_messenger: impl AsRef<ShardMessenger>,
    ) -> ReactionCollector {
        self.await_reaction(shard_messenger)
    }

    /// Returns a builder which can be awaited to obtain a single component interactions or a
    /// stream of component interactions on this message.
    #[cfg(feature = "collector")]
    pub fn await_component_interaction(
        &self,
        shard_messenger: impl AsRef<ShardMessenger>,
    ) -> ComponentInteractionCollector {
        ComponentInteractionCollector::new(shard_messenger).message_id(self.id)
    }

    /// Same as [`Self::await_component_interaction`].
    #[cfg(feature = "collector")]
    pub fn await_component_interactions(
        &self,
        shard_messenger: impl AsRef<ShardMessenger>,
    ) -> ComponentInteractionCollector {
        self.await_component_interaction(shard_messenger)
    }

    /// Returns a builder which can be awaited to obtain a model submit interaction or stream of
    /// modal submit interactions on this message.
    #[cfg(feature = "collector")]
    pub fn await_modal_interaction(
        &self,
        shard_messenger: impl AsRef<ShardMessenger>,
    ) -> ModalInteractionCollector {
        ModalInteractionCollector::new(shard_messenger).message_id(self.id)
    }

    /// Same as [`Self::await_modal_interaction`].
    #[cfg(feature = "collector")]
    pub fn await_modal_interactions(
        &self,
        shard_messenger: impl AsRef<ShardMessenger>,
    ) -> ModalInteractionCollector {
        self.await_modal_interaction(shard_messenger)
    }

    /// Retrieves the message channel's category ID if the channel has one.
    pub async fn category_id(&self, cache_http: impl CacheHttp) -> Option<ChannelId> {
        self.channel_id.to_channel(cache_http).await.ok()?.guild()?.parent_id
    }
}

impl AsRef<MessageId> for Message {
    fn as_ref(&self) -> &MessageId {
        &self.id
    }
}

impl From<Message> for MessageId {
    /// Gets the Id of a [`Message`].
    fn from(message: Message) -> MessageId {
        message.id
    }
}

impl<'a> From<&'a Message> for MessageId {
    /// Gets the Id of a [`Message`].
    fn from(message: &Message) -> MessageId {
        message.id
    }
}

/// A representation of a reaction to a message.
///
/// Multiple of the same [reaction type] are sent into one [`MessageReaction`], with an associated
/// [`Self::count`].
///
/// [Discord docs](https://discord.com/developers/docs/resources/channel#reaction-object).
///
/// [reaction type]: ReactionType
#[cfg_attr(feature = "typesize", derive(typesize::derive::TypeSize))]
#[derive(Clone, Debug, Deserialize, Serialize)]
#[non_exhaustive]
pub struct MessageReaction {
    /// The amount of the type of reaction that have been sent for the associated message.
    pub count: u64,
    /// Indicator of whether the current user has sent the type of reaction.
    pub me: bool,
    /// The type of reaction.
    #[serde(rename = "emoji")]
    pub reaction_type: ReactionType,
}

enum_number! {
    /// Differentiates between regular and different types of system messages.
    ///
    /// [Discord docs](https://discord.com/developers/docs/resources/channel#message-object-message-types).
    #[derive(Clone, Copy, Debug, Default, Eq, Hash, Ord, PartialEq, PartialOrd, Deserialize, Serialize)]
    #[cfg_attr(feature = "typesize", derive(typesize::derive::TypeSize))]
    #[serde(from = "u8", into = "u8")]
    #[non_exhaustive]
    pub enum MessageType {
        /// A regular message.
        #[default]
        Regular = 0,
        /// An indicator that a recipient was added by the author.
        GroupRecipientAddition = 1,
        /// An indicator that a recipient was removed by the author.
        GroupRecipientRemoval = 2,
        /// An indicator that a call was started by the author.
        GroupCallCreation = 3,
        /// An indicator that the group name was modified by the author.
        GroupNameUpdate = 4,
        /// An indicator that the group icon was modified by the author.
        GroupIconUpdate = 5,
        /// An indicator that a message was pinned by the author.
        PinsAdd = 6,
        /// An indicator that a member joined the guild.
        MemberJoin = 7,
        /// An indicator that someone has boosted the guild.
        NitroBoost = 8,
        /// An indicator that the guild has reached nitro tier 1
        NitroTier1 = 9,
        /// An indicator that the guild has reached nitro tier 2
        NitroTier2 = 10,
        /// An indicator that the guild has reached nitro tier 3
        NitroTier3 = 11,
        /// An indicator that the channel is now following a news channel
        ChannelFollowAdd = 12,
        /// An indicator that the guild is disqualified for Discovery Feature
        GuildDiscoveryDisqualified = 14,
        /// An indicator that the guild is requalified for Discovery Feature
        GuildDiscoveryRequalified = 15,
        /// The first warning before guild discovery removal.
        GuildDiscoveryGracePeriodInitialWarning = 16,
        /// The last warning before guild discovery removal.
        GuildDiscoveryGracePeriodFinalWarning = 17,
        /// Message sent to inform users that a thread was created.
        ThreadCreated = 18,
        /// A message reply.
        InlineReply = 19,
        /// A slash command.
        ChatInputCommand = 20,
        /// A thread start message.
        ThreadStarterMessage = 21,
        /// Server setup tips.
        GuildInviteReminder = 22,
        /// A context menu command.
        ContextMenuCommand = 23,
        /// A message from an auto moderation action.
        AutoModAction = 24,
        RoleSubscriptionPurchase = 25,
        InteractionPremiumUpsell = 26,
        StageStart = 27,
        StageEnd = 28,
        StageSpeaker = 29,
        StageTopic = 31,
        GuildApplicationPremiumSubscription = 32,
        _ => Unknown(u8),
    }
}

enum_number! {
    /// [Discord docs](https://discord.com/developers/docs/resources/channel#message-object-message-activity-types).
    #[derive(Clone, Copy, Debug, Eq, Hash, Ord, PartialEq, PartialOrd, Deserialize, Serialize)]
    #[cfg_attr(feature = "typesize", derive(typesize::derive::TypeSize))]
    #[serde(from = "u8", into = "u8")]
    #[non_exhaustive]
    pub enum MessageActivityKind {
        Join = 1,
        Spectate = 2,
        Listen = 3,
        JoinRequest = 5,
        _ => Unknown(u8),
    }
}

/// Rich Presence application information.
///
/// [Discord docs](https://discord.com/developers/docs/resources/application#application-object),
/// [subset undocumented](https://discord.com/developers/docs/resources/channel#message-object-message-structure).
#[cfg_attr(feature = "typesize", derive(typesize::derive::TypeSize))]
#[derive(Clone, Debug, Deserialize, Serialize)]
#[non_exhaustive]
pub struct MessageApplication {
    /// ID of the application.
    pub id: ApplicationId,
    /// ID of the embed's image asset.
    pub cover_image: Option<ImageHash>,
    /// Application's description.
    pub description: String,
    /// ID of the application's icon.
    pub icon: Option<ImageHash>,
    /// Name of the application.
    pub name: String,
}

/// Rich Presence activity information.
///
/// [Discord docs](https://discord.com/developers/docs/resources/channel#message-object-message-activity-structure).
#[cfg_attr(feature = "typesize", derive(typesize::derive::TypeSize))]
#[derive(Clone, Debug, Deserialize, Serialize)]
#[non_exhaustive]
pub struct MessageActivity {
    /// Kind of message activity.
    #[serde(rename = "type")]
    pub kind: MessageActivityKind,
    /// `party_id` from a Rich Presence event.
    pub party_id: Option<String>,
}

/// Reference data sent with crossposted messages.
///
/// [Discord docs](https://discord.com/developers/docs/resources/channel#message-reference-object-message-reference-structure).
#[cfg_attr(feature = "typesize", derive(typesize::derive::TypeSize))]
#[derive(Clone, Debug, Deserialize, Serialize)]
#[non_exhaustive]
pub struct MessageReference {
    /// ID of the originating message.
    pub message_id: Option<MessageId>,
    /// ID of the originating message's channel.
    pub channel_id: ChannelId,
    /// ID of the originating message's guild.
    pub guild_id: Option<GuildId>,
    /// When sending, whether to error if the referenced message doesn't exist instead of sending
    /// as a normal (non-reply) message, default true.
    pub fail_if_not_exists: Option<bool>,
}

impl From<&Message> for MessageReference {
    fn from(m: &Message) -> Self {
        Self {
            message_id: Some(m.id),
            channel_id: m.channel_id,
            guild_id: m.guild_id,
            fail_if_not_exists: None,
        }
    }
}

impl From<(ChannelId, MessageId)> for MessageReference {
    fn from(pair: (ChannelId, MessageId)) -> Self {
        Self {
            message_id: Some(pair.1),
            channel_id: pair.0,
            guild_id: None,
            fail_if_not_exists: None,
        }
    }
}

/// [Discord docs](https://discord.com/developers/docs/resources/channel#channel-mention-object).
#[cfg_attr(feature = "typesize", derive(typesize::derive::TypeSize))]
#[derive(Clone, Debug, Deserialize, Serialize)]
#[non_exhaustive]
pub struct ChannelMention {
    /// ID of the channel.
    pub id: ChannelId,
    /// ID of the guild containing the channel.
    pub guild_id: GuildId,
    /// The kind of channel
    #[serde(rename = "type")]
    pub kind: ChannelType,
    /// The name of the channel
    pub name: String,
}

bitflags! {
    /// Describes extra features of the message.
    ///
    /// [Discord docs](https://discord.com/developers/docs/resources/channel#message-object-message-flags).
    #[cfg_attr(feature = "typesize", derive(typesize::derive::TypeSize))]
    #[derive(Copy, Clone, Default, Debug, Eq, Hash, PartialEq)]
    pub struct MessageFlags: u64 {
        /// This message has been published to subscribed channels (via Channel Following).
        const CROSSPOSTED = 1 << 0;
        /// This message originated from a message in another channel (via Channel Following).
        const IS_CROSSPOST = 1 << 1;
        /// Do not include any embeds when serializing this message.
        const SUPPRESS_EMBEDS = 1 << 2;
        /// The source message for this crosspost has been deleted (via Channel Following).
        const SOURCE_MESSAGE_DELETED = 1 << 3;
        /// This message came from the urgent message system.
        const URGENT = 1 << 4;
        /// This message has an associated thread, with the same id as the message.
        const HAS_THREAD = 1 << 5;
        /// This message is only visible to the user who invoked the Interaction.
        const EPHEMERAL = 1 << 6;
        /// This message is an Interaction Response and the bot is "thinking".
        const LOADING = 1 << 7;
        /// This message failed to mention some roles and add their members to the thread.
        const FAILED_TO_MENTION_SOME_ROLES_IN_THREAD = 1 << 8;
        /// This message will not trigger push and desktop notifications.
        const SUPPRESS_NOTIFICATIONS = 1 << 12;
        /// This message is a voice message.
        ///
        /// Voice messages have the following properties:
        /// - They cannot be edited.
        /// - Only a single audio attachment is allowed. No content, stickers, etc...
        /// - The [`Attachment`] has additional fields: `duration_secs` and `waveform`.
        ///
        /// As of 2023-04-14, clients upload a 1 channel, 48000 Hz, 32kbps Opus stream in an OGG container.
        /// The encoding is a Discord implementation detail and may change without warning or documentation.
        ///
        /// As of 2023-04-20, bots are currently not able to send voice messages
        /// ([source](https://github.com/discord/discord-api-docs/pull/6082)).
        const IS_VOICE_MESSAGE = 1 << 13;
    }
}

#[cfg(feature = "model")]
impl MessageId {
    /// Returns a link referencing this message. When clicked, users will jump to the message. The
    /// link will be valid for messages in either private channels or guilds.
    #[must_use]
    pub fn link(&self, channel_id: ChannelId, guild_id: Option<GuildId>) -> String {
        if let Some(guild_id) = guild_id {
            format!("https://discord.com/channels/{guild_id}/{channel_id}/{self}")
        } else {
            format!("https://discord.com/channels/@me/{channel_id}/{self}")
        }
    }

    /// Same as [`Self::link`] but tries to find the [`GuildId`] if it is not provided.
    pub async fn link_ensured(
        &self,
        cache_http: impl CacheHttp,
        channel_id: ChannelId,
        mut guild_id: Option<GuildId>,
    ) -> String {
        if guild_id.is_none() {
            let found_channel = channel_id.to_channel(cache_http).await;

            if let Ok(channel) = found_channel {
                if let Some(c) = channel.guild() {
                    guild_id = Some(c.guild_id);
                }
            }
        }

        self.link(channel_id, guild_id)
    }
}

#[cfg_attr(feature = "typesize", derive(typesize::derive::TypeSize))]
#[derive(Clone, Debug, Serialize)]
#[serde(untagged)]
pub enum Nonce {
    String(String),
    Number(u64),
}

impl<'de> serde::Deserialize<'de> for Nonce {
    fn deserialize<D: Deserializer<'de>>(deserializer: D) -> StdResult<Self, D::Error> {
        Ok(StrOrInt::deserialize(deserializer)?.into_enum(Self::String, Self::Number))
    }
}

/// [Discord docs](https://discord.com/developers/docs/resources/channel#role-subscription-data-object)
#[cfg_attr(feature = "typesize", derive(typesize::derive::TypeSize))]
#[derive(Clone, Debug, Deserialize, Serialize)]
pub struct RoleSubscriptionData {
    /// The id of the sku and listing that the user is subscribed to.
    pub role_subscription_listing_id: SkuId,
    /// The name of the tier that the user is subscribed to.
    pub tier_name: String,
    /// The cumulative number of months that the user has been subscribed for.
    pub total_months_subscribed: u16,
    /// Whether this notification is for a renewal rather than a new purchase.
    pub is_renewal: bool,
}