use chrono::{DateTime, FixedOffset};
use std::fmt::{Display, Formatter, Result as FmtResult};
use super::deserialize_sync_user;
use model::*;

#[cfg(feature = "model")]
use std::borrow::Cow;
#[cfg(feature = "cache")]
use CACHE;
#[cfg(feature = "cache")]
use internal::prelude::*;
#[cfg(all(feature = "cache", feature = "model"))]
use http;
#[cfg(all(feature = "builder", feature = "cache", feature = "model"))]
use builder::EditMember;
#[cfg(all(feature = "cache", feature = "model", feature = "utils"))]
use utils::Colour;

pub trait BanOptions {
    fn dmd(&self) -> u8 { 0 }
    fn reason(&self) -> &str { "" }
}

impl BanOptions for u8 {
    fn dmd(&self) -> u8 { *self }
}

impl BanOptions for str {
    fn reason(&self) -> &str { self }
}

impl BanOptions for String {
    fn reason(&self) -> &str { self }
}

impl<'a> BanOptions for (u8, &'a str) {
    fn dmd(&self) -> u8 { self.0 }

    fn reason(&self) -> &str { self.1 }
}

impl BanOptions for (u8, String) {
    fn dmd(&self) -> u8 { self.0 }

    fn reason(&self) -> &str { &self.1 }
}

/// Information about a member of a guild.
#[derive(Clone, Debug, Deserialize)]
pub struct Member {
    /// Indicator of whether the member can hear in voice channels.
    pub deaf: bool,
    /// The unique Id of the guild that the member is a part of.
    pub guild_id: GuildId,
    /// Timestamp representing the date when the member joined.
    pub joined_at: Option<DateTime<FixedOffset>>,
    /// Indicator of whether the member can speak in voice channels.
    pub mute: bool,
    /// The member's nickname, if present.
    ///
    /// Can't be longer than 32 characters.
    pub nick: Option<String>,
    /// Vector of Ids of [`Role`]s given to the member.
    pub roles: Vec<RoleId>,
    /// Attached User struct.
    #[serde(deserialize_with = "deserialize_sync_user")]
    pub user: Arc<RwLock<User>>,
}

#[cfg(feature = "model")]
impl Member {
    /// Adds a [`Role`] to the member, editing its roles in-place if the request
    /// was successful.
    ///
    /// **Note**: Requires the [Manage Roles] permission.
    ///
    /// [`Role`]: struct.Role.html
    /// [Manage Roles]: permissions/constant.MANAGE_ROLES.html
    #[cfg(feature = "cache")]
    pub fn add_role<R: Into<RoleId>>(&mut self, role_id: R) -> Result<()> {
        let role_id = role_id.into();

        if self.roles.contains(&role_id) {
            return Ok(());
        }

        match http::add_member_role(self.guild_id.0, self.user.read().unwrap().id.0, role_id.0) {
            Ok(()) => {
                self.roles.push(role_id);

                Ok(())
            },
            Err(why) => Err(why),
        }
    }

    /// Adds one or multiple [`Role`]s to the member, editing
    /// its roles in-place if the request was successful.
    ///
    /// **Note**: Requires the [Manage Roles] permission.
    ///
    /// [`Role`]: struct.Role.html
    /// [Manage Roles]: permissions/constant.MANAGE_ROLES.html
    #[cfg(feature = "cache")]
    pub fn add_roles(&mut self, role_ids: &[RoleId]) -> Result<()> {
        self.roles.extend_from_slice(role_ids);

        let map = EditMember::default().roles(&self.roles).0;

        match http::edit_member(self.guild_id.0, self.user.read().unwrap().id.0, &map) {
            Ok(()) => Ok(()),
            Err(why) => {
                self.roles.retain(|r| !role_ids.contains(r));

                Err(why)
            },
        }
    }

    /// Ban the member from its guild, deleting the last X number of
    /// days' worth of messages.
    ///
    /// **Note**: Requires the [Ban Members] permission.
    ///
    /// # Errors
    ///
    /// Returns a [`ModelError::GuildNotFound`] if the guild could not be
    /// found.
    ///
    /// [`ModelError::GuildNotFound`]: enum.ModelError.html#variant.GuildNotFound
    ///
    /// [Ban Members]: permissions/constant.BAN_MEMBERS.html
    #[cfg(feature = "cache")]
    pub fn ban<BO: BanOptions>(&self, ban_options: BO) -> Result<()> {
        let dmd = ban_options.dmd();
        if dmd > 7 {
            return Err(Error::Model(ModelError::DeleteMessageDaysAmount(dmd)));
        }

        let reason = ban_options.reason();

        if reason.len() > 512 {
            return Err(Error::ExceededLimit(reason.to_string(), 512));
        }

        http::ban_user(
            self.guild_id.0,
            self.user.read().unwrap().id.0,
            dmd,
            &*reason,
        )
    }

    /// Determines the member's colour.
    #[cfg(all(feature = "cache", feature = "utils"))]
    pub fn colour(&self) -> Option<Colour> {
        let cache = CACHE.read().unwrap();
        let guild = match cache.guilds.get(&self.guild_id) {
            Some(guild) => guild.read().unwrap(),
            None => return None,
        };

        let mut roles = self.roles
            .iter()
            .filter_map(|role_id| guild.roles.get(role_id))
            .collect::<Vec<&Role>>();
        roles.sort_by(|a, b| b.cmp(a));

        let default = Colour::default();

        roles
            .iter()
            .find(|r| r.colour.0 != default.0)
            .map(|r| r.colour)
    }

    /// Calculates the member's display name.
    ///
    /// The nickname takes priority over the member's username if it exists.
    #[inline]
    pub fn display_name(&self) -> Cow<String> {
        self.nick
            .as_ref()
            .map(Cow::Borrowed)
            .unwrap_or_else(|| Cow::Owned(self.user.read().unwrap().name.clone()))
    }

    /// Returns the DiscordTag of a Member, taking possible nickname into account.
    #[inline]
    pub fn distinct(&self) -> String {
        format!(
            "{}#{}",
            self.display_name(),
            self.user.read().unwrap().discriminator
        )
    }

    /// Edits the member with the given data. See [`Guild::edit_member`] for
    /// more information.
    ///
    /// See [`EditMember`] for the permission(s) required for separate builder
    /// methods, as well as usage of this.
    ///
    /// [`Guild::edit_member`]: ../model/struct.Guild.html#method.edit_member
    /// [`EditMember`]: ../builder/struct.EditMember.html
    #[cfg(feature = "cache")]
    pub fn edit<F: FnOnce(EditMember) -> EditMember>(&self, f: F) -> Result<()> {
        let map = f(EditMember::default()).0;

        http::edit_member(self.guild_id.0, self.user.read().unwrap().id.0, &map)
    }

    /// Kick the member from the guild.
    ///
    /// **Note**: Requires the [Kick Members] permission.
    ///
    /// # Examples
    ///
    /// Kick a member from its guild:
    ///
    /// ```rust,ignore
    /// // assuming a `member` has already been bound
    /// match member.kick() {
    ///     Ok(()) => println!("Successfully kicked member"),
    ///     Err(Error::Model(ModelError::GuildNotFound)) => {
    ///         println!("Couldn't determine guild of member");
    ///     },
    ///     Err(Error::Model(ModelError::InvalidPermissions(missing_perms))) => {
    ///         println!("Didn't have permissions; missing: {:?}", missing_perms);
    ///     },
    ///     _ => {},
    /// }
    /// ```
    ///
    /// # Errors
    ///
    /// Returns a [`ModelError::GuildNotFound`] if the Id of the member's guild
    /// could not be determined.
    ///
    /// If the `cache` is enabled, returns a [`ModelError::InvalidPermissions`]
    /// if the current user does not have permission to perform the kick.
    ///
    /// [`ModelError::GuildNotFound`]: enum.ModelError.html#variant.GuildNotFound
    /// [`ModelError::InvalidPermissions`]: enum.ModelError.html#variant.InvalidPermissions
    /// [Kick Members]: permissions/constant.KICK_MEMBERS.html
    pub fn kick(&self) -> Result<()> {
        #[cfg(feature = "cache")]
        {
            let req = permissions::KICK_MEMBERS;

            let has_perms = CACHE
                .read()
                .unwrap()
                .guilds
                .get(&self.guild_id)
                .map(|guild| guild.read().unwrap().has_perms(req));

            if let Some(Ok(false)) = has_perms {
                return Err(Error::Model(ModelError::InvalidPermissions(req)));
            }
        }

        self.guild_id.kick(self.user.read().unwrap().id)
    }

    /// Returns the permissions for the member.
    ///
    /// # Examples
    ///
    /// ```rust,ignore
    /// // assuming there's a `member` variable gotten from anything.
    /// println!("The permission bits for the member are: {}",
    /// member.permissions().expect("permissions").bits);
    /// ```
    ///
    /// # Errors
    ///
    /// Returns a [`ModelError::GuildNotFound`] if the guild the member's in could not be
    /// found in the cache.
    ///
    /// [`ModelError::GuildNotFound`]: enum.ModelError.html#variant.GuildNotFound
    #[cfg(feature = "cache")]
    pub fn permissions(&self) -> Result<Permissions> {
        let guild = match self.guild_id.find() {
            Some(guild) => guild,
            None => return Err(From::from(ModelError::GuildNotFound)),  
        };

        let guild = guild.read().unwrap();

        Ok(
            guild
                .permissions_for(ChannelId(guild.id.0), self.user.read().unwrap().id),
        )
    }

    /// Removes a [`Role`] from the member, editing its roles in-place if the
    /// request was successful.
    ///
    /// **Note**: Requires the [Manage Roles] permission.
    ///
    /// [`Role`]: struct.Role.html
    /// [Manage Roles]: permissions/constant.MANAGE_ROLES.html
    #[cfg(feature = "cache")]
    pub fn remove_role<R: Into<RoleId>>(&mut self, role_id: R) -> Result<()> {
        let role_id = role_id.into();

        if !self.roles.contains(&role_id) {
            return Ok(());
        }

        match http::remove_member_role(self.guild_id.0, self.user.read().unwrap().id.0, role_id.0) {
            Ok(()) => {
                self.roles.retain(|r| r.0 != role_id.0);

                Ok(())
            },
            Err(why) => Err(why),
        }
    }

    /// Removes one or multiple [`Role`]s from the member.
    ///
    /// **Note**: Requires the [Manage Roles] permission.
    ///
    /// [`Role`]: struct.Role.html
    /// [Manage Roles]: permissions/constant.MANAGE_ROLES.html
    #[cfg(feature = "cache")]
    pub fn remove_roles(&mut self, role_ids: &[RoleId]) -> Result<()> {
        self.roles.retain(|r| !role_ids.contains(r));

        let map = EditMember::default().roles(&self.roles).0;

        match http::edit_member(self.guild_id.0, self.user.read().unwrap().id.0, &map) {
            Ok(()) => Ok(()),
            Err(why) => {
                self.roles.extend_from_slice(role_ids);

                Err(why)
            },
        }
    }

    /// Retrieves the full role data for the user's roles.
    ///
    /// This is shorthand for manually searching through the CACHE.
    ///
    /// If role data can not be found for the member, then `None` is returned.
    #[cfg(feature = "cache")]
    pub fn roles(&self) -> Option<Vec<Role>> {
        CACHE
            .read()
            .unwrap()
            .guilds
            .values()
            .find(|guild| {
                guild.read().unwrap().members.values().any(|m| {
                    m.user.read().unwrap().id == self.user.read().unwrap().id &&
                    m.joined_at == self.joined_at
                })
            })
            .map(|guild| {
                guild
                    .read()
                    .unwrap()
                    .roles
                    .values()
                    .filter(|role| self.roles.contains(&role.id))
                    .cloned()
                    .collect()
            })
    }

    /// Unbans the [`User`] from the guild.
    ///
    /// **Note**: Requires the [Ban Members] permission.
    ///
    /// # Errors
    ///
    /// If the `cache` is enabled, returns a [`ModelError::InvalidPermissions`]
    /// if the current user does not have permission to perform bans.
    ///
    /// [`ModelError::InvalidPermissions`]: enum.ModelError.html#variant.InvalidPermissions
    /// [`User`]: struct.User.html
    /// [Ban Members]: permissions/constant.BAN_MEMBERS.html
    #[cfg(feature = "cache")]
    pub fn unban(&self) -> Result<()> {
        http::remove_ban(self.guild_id.0, self.user.read().unwrap().id.0)
    }
}

impl Display for Member {
    /// Mentions the user so that they receive a notification.
    ///
    /// # Examples
    ///
    /// ```rust,ignore
    /// // assumes a `member` has already been bound
    /// println!("{} is a member!", member);
    /// ```
    ///
    // This is in the format of `<@USER_ID>`.
    fn fmt(&self, f: &mut Formatter) -> FmtResult {
        Display::fmt(&self.user.read().unwrap().mention(), f)
    }
}