use protocol::messages::{

    HWProtocolMessage::{self, Rnd}, HWServerMessage::{self, ChatMsg},

};

use rand::{self, Rng};

use server::{actions::Action, room::HWRoom, server::HWServer};

pub fn rnd_action(options: Vec<String>, room: Option<&mut HWRoom>) -> Vec<Action> {

    if let Some(room) = room {

        let msg = rnd_reply(options);

        vec![msg.send_all().in_room(room.id).action()]

    } else {

        Vec::new()

    }

}

fn rnd_reply(options: Vec<String>) -> HWServerMessage {

    let options = if options.is_empty() {

        vec!["heads".to_owned(), "tails".to_owned()]

    } else {

        options

    };

    let reply = rand::thread_rng().choose(&options).unwrap();

    let msg = ChatMsg {

        nick: "[random]".to_owned(),

        msg: reply.clone(),

    };

    msg

}

#[cfg(test)]

mod tests {

    use super::*;

    use protocol::messages::HWServerMessage::ChatMsg;

    use server::actions::{

        Action::{self, Send}, PendingMessage,

    };

    fn reply2string(r: HWServerMessage) -> String {

        match r {

            ChatMsg { msg: p, .. } => String::from(p),

            _ => panic!("expected a ChatMsg"),

        }

    }

    fn run_handle_test(opts: Vec<String>) {

        let opts2 = opts.clone();

        for opt in opts {

            while reply2string(rnd_reply(opts2.clone())) != opt {}

        }

    }

    /// This test terminates almost surely.

    #[test]

    fn test_handle_rnd_empty() {

        run_handle_test(vec![])

    }

    /// This test terminates almost surely.

    #[test]

    fn test_handle_rnd_nonempty() {

        run_handle_test(vec!["A".to_owned(), "B".to_owned(), "C".to_owned()])

    }

    /// This test terminates almost surely (strong law of large numbers)

    #[test]

    fn test_distribution() {

        let eps = 0.000001;

        let lim = 0.5;

        let opts = vec![0.to_string(), 1.to_string()];

        let mut ones = 0;

        let mut tries = 0;

        while tries < 1000 || ((ones as f64 / tries as f64) - lim).abs() >= eps {

            tries += 1;

            if reply2string(rnd_reply(opts.clone())) == 1.to_string() {

                ones += 1;

            }

        }

    }

}