//! # Friends helper
//!
//! @author Pierre Hubert



use crate::constants::database_tables_names::{FRIENDS_TABLE, USERS_TABLE};
use crate::data::error::{ExecError, ResultBoxError};
use crate::data::friend::Friend;
use crate::data::friendship_status::FriendshipStatus;
use crate::data::user::UserID;
use crate::helpers::database;
use crate::helpers::database::QueryInfo;

/// Structure used to get a friend information
pub struct GetFriendsQuery {
    only_accepted: bool,
    only_following: bool,
    only_followers: bool,
    target_user: UserID,
    friend_id: Option<UserID>,
    common_with_user: Option<UserID>,
}

impl GetFriendsQuery {
    /// Construct a new request
    pub fn new(target_user: &UserID) -> GetFriendsQuery {
        GetFriendsQuery {
            only_accepted: false,
            only_following: false,
            only_followers: false,
            target_user: target_user.clone(),
            friend_id: None,
            common_with_user: None,
        }
    }

    pub fn set_only_accepted(mut self, accepted: bool) -> GetFriendsQuery {
        self.only_accepted = accepted;
        self
    }

    /// Specify whether only the friends followed by friend_id should be selected
    pub fn set_only_following(mut self, following: bool) -> GetFriendsQuery {
        self.only_following = following;
        self
    }

    /// Specify whether only the friends following friend_id should be selected
    pub fn set_only_followers(mut self, following: bool) -> GetFriendsQuery {
        self.only_followers = following;
        self
    }

    /// Specify whether all the returned friends should be common with a specified user
    pub fn set_only_common_with(mut self, user: &UserID) -> GetFriendsQuery {
        self.common_with_user = Some(user.clone());
        self
    }

    /// Get the list of friends
    pub fn exec(self) -> ResultBoxError<Vec<Friend>> {
        get_list(&self)
    }

    /// Get information about a single friendship
    pub fn get_single_friend(mut self, friend_id: &UserID) -> ResultBoxError<Friend> {
        self.friend_id = Some(friend_id.clone());
        get_list(&self)?
            .pop()
            .ok_or(ExecError::boxed_new("Single friend not found!"))
    }
}

/// Get the list of friends of a user
fn get_list(friend_query: &GetFriendsQuery) -> ResultBoxError<Vec<Friend>> {
    let mut query = database::QueryInfo::new(FRIENDS_TABLE)
        .alias("f")
        .cond_user_id("ID_personne", &friend_query.target_user)
        .join(USERS_TABLE, "u", "f.ID_amis = u.ID")
        .add_field("u.last_activity")
        .add_field("f.ID_amis")
        .add_field("f.actif")
        .add_field("f.abonnement")
        .add_field("f.autoriser_post_page")
        .set_order("u.last_activity DESC");

    if let Some(friend_id) = friend_query.friend_id.as_ref() {
        query = query.cond_user_id("ID_amis", friend_id);
    }

    if friend_query.only_accepted {
        query = query.cond_legacy_bool("f.actif", true);
    }

    if friend_query.only_following {
        query = query.cond_legacy_bool("f.abonnement", true);
    }

    let mut custom_where = String::new();

    if friend_query.only_followers {
        custom_where = " EXISTS (SELECT * FROM amis d WHERE d.ID_personne = f.ID_amis AND d.ID_amis = f.ID_personne AND abonnement = 1) ".to_string();
    }

    if let Some(user_id) = &friend_query.common_with_user {
        if !custom_where.is_empty() {
            custom_where.push_str(" AND ");
        }

        custom_where.push_str(" (f.ID_amis = ? OR EXISTS (SELECT * FROM amis d WHERE d.ID_personne = ? AND d.ID_amis = f.ID_amis AND actif = 1) ) ");
        query = query.add_custom_where_argument_user_id(user_id);
        query = query.add_custom_where_argument_user_id(user_id);
    }

    if !custom_where.is_empty() {
        query = query.set_custom_where(&custom_where);
    }

    query.exec(db_to_friend)
}

/// get the list of friends that allows a given user to create posts on their page
pub fn get_list_that_allow_posts_from_user(user_id: &UserID) -> ResultBoxError<Vec<UserID>> {
    database::QueryInfo::new(FRIENDS_TABLE)
        .cond_legacy_bool("autoriser_post_page", true)
        .cond_legacy_bool("actif", true)
        .cond_user_id("ID_amis", user_id)
        .add_field("ID_personne as user_id")
        .exec(|r| r.get_user_id("user_id"))
}

/// Send a new friendship request
pub fn send_request(user_id: &UserID, target_user: &UserID) -> ResultBoxError {
    database::InsertQuery::new(FRIENDS_TABLE)
        .add_user_id("ID_personne", target_user)
        .add_user_id("ID_amis", user_id)
        .add_legacy_bool("actif", false)
        .insert_drop_result()
}

/// Remove a friendship request
pub fn remove_request(user_id: &UserID, target_user: &UserID) -> ResultBoxError {
    database::DeleteQuery::new(FRIENDS_TABLE)
        .cond_user_id("ID_personne", target_user)
        .cond_user_id("ID_amis", user_id)
        .cond_legacy_bool("actif", false)
        .exec()
}

/// Check out whether a user has sent a request to another user
pub fn sent_request(user_id: &UserID, target_user: &UserID) -> ResultBoxError<bool> {
    database::QueryInfo::new(FRIENDS_TABLE)
        .cond_user_id("ID_personne", target_user)
        .cond_user_id("ID_amis", user_id)
        .cond_legacy_bool("actif", false)
        .exec_count()
        .map(|f| f > 0)
}

/// Respond to a friendship request
pub fn respond_request(user_id: &UserID, friend_id: &UserID, accept: bool) -> ResultBoxError {
    // Delete the request
    remove_request(friend_id, user_id)?;

    if accept {
        database::InsertQuery::new(FRIENDS_TABLE)
            .add_user_id("ID_personne", user_id)
            .add_user_id("ID_amis", friend_id)
            .add_legacy_bool("actif", true)
            .insert_drop_result()?;

        database::InsertQuery::new(FRIENDS_TABLE)
            .add_user_id("ID_personne", friend_id)
            .add_user_id("ID_amis", user_id)
            .add_legacy_bool("actif", true)
            .insert_drop_result()?;
    }

    Ok(())
}

/// Check out whether two users are friend or not
pub fn are_friend(user_one: &UserID, user_two: &UserID) -> ResultBoxError<bool> {
    Ok(database::count(QueryInfo::new(FRIENDS_TABLE)
        .cond_user_id("ID_personne", user_one)
        .cond_user_id("ID_amis", user_two)
        .cond_i64("actif", 1))? > 0)
}

/// Delete a friendship
pub fn remove_friendship(user_one: &UserID, user_two: &UserID) -> ResultBoxError {
    database::DeleteQuery::new(FRIENDS_TABLE)
        .cond_user_id("ID_personne", user_one)
        .cond_user_id("ID_amis", user_two)
        .exec()?;

    database::DeleteQuery::new(FRIENDS_TABLE)
        .cond_user_id("ID_personne", user_two)
        .cond_user_id("ID_amis", user_one)
        .exec()?;

    Ok(())
}

/// Count the number of friends of a user
pub fn count_friends(user_id: &UserID) -> ResultBoxError<usize> {
    QueryInfo::new(FRIENDS_TABLE)
        .cond_user_id("ID_amis", user_id)
        .cond_u32("actif", 1)
        .exec_count()
}

/// Check if a user can create posts on another friend's page
pub fn can_post_texts(user_id: &UserID, target_user: &UserID) -> ResultBoxError<bool> {
    QueryInfo::new(FRIENDS_TABLE)
        .cond_user_id("ID_personne", target_user)
        .cond_user_id("ID_amis", user_id)
        .add_field("autoriser_post_page")
        .query_row(|res| res.get_legacy_bool("autoriser_post_page"))
        .or(Ok(false))
}

/// Check out whether a user is following another user or not
pub fn is_following(user_id: &UserID, friend_id: &UserID) -> ResultBoxError<bool> {
    database::QueryInfo::new(FRIENDS_TABLE)
        .cond_user_id("ID_personne", user_id)
        .cond_user_id("ID_amis", friend_id)
        .cond_legacy_bool("actif", true)
        .cond_legacy_bool("abonnement", true)
        .exec_count()
        .map(|f| f > 0)
}

/// Update following status of a friendship
pub fn set_following(user_id: &UserID, friend_id: &UserID, follow: bool) -> ResultBoxError {
    database::UpdateInfo::new(FRIENDS_TABLE)
        .cond_user_id("ID_personne", user_id)
        .cond_user_id("ID_amis", friend_id)
        .set_legacy_bool("abonnement", follow)
        .exec()
}

/// Specify whether a friend is allowed to create posts on current user's page or not
pub fn set_can_post_texts(user_id: &UserID, friend_id: &UserID, allow: bool) -> ResultBoxError {
    database::UpdateInfo::new(FRIENDS_TABLE)
        .cond_user_id("ID_personne", user_id)
        .cond_user_id("ID_amis", friend_id)
        .set_legacy_bool("autoriser_post_page", allow)
        .exec()
}

/// Get the status of a friendship
pub fn get_status(user_id: &UserID, friend_id: &UserID) -> ResultBoxError<FriendshipStatus> {
    let mut status = FriendshipStatus {
        are_friend: false,
        sent_request: false,
        received_request: false,
        following: false,
    };

    status.are_friend = are_friend(user_id, friend_id)?;

    match status.are_friend {
        false => {
            status.sent_request = sent_request(user_id, friend_id)?;
            status.received_request = sent_request(friend_id, user_id)?;
        }

        true => {
            status.following = is_following(user_id, friend_id)?;
        }
    }

    Ok(status)
}

/// Count the number of friendship requests of a user
pub fn count_requests(user_id: &UserID) -> ResultBoxError<u64> {
    database::QueryInfo::new(FRIENDS_TABLE)
        .cond_user_id("ID_personne", user_id)
        .cond_legacy_bool("actif", false)
        .exec_count()
        .map(|r| r as u64)
}

/// Delete all the friends of a given user
pub fn delete_all_user(user_id: &UserID) -> ResultBoxError {
    database::DeleteQuery::new(FRIENDS_TABLE)
        .cond_user_id("ID_personne", user_id)
        .exec()?;

    database::DeleteQuery::new(FRIENDS_TABLE)
        .cond_user_id("ID_amis", user_id)
        .exec()
}

/// Turn a database entry into a Friend structure
fn db_to_friend(row: &database::RowResult) -> ResultBoxError<Friend> {
    Ok(Friend {
        friend_id: row.get_user_id("ID_amis")?,
        accepted: row.get_legacy_bool("actif")?,
        following: row.get_legacy_bool("abonnement")?,
        last_activity_time: row.get_u64("last_activity")?,
        can_post_texts: row.get_legacy_bool("autoriser_post_page")?,
    })
}