extern crate toml;
extern crate crossbeam;
extern crate discord;
extern crate rand;
extern crate pvn;
extern crate echobox;
extern crate transformable_channels;
extern crate stc;
extern crate regex;

#[macro_use]
extern crate hlua;

use std::collections::BTreeMap;
use toml::Table;

mod modules;
use modules::Module;
use modules::loader::{ModuleLoader, ModuleLoaderError};

mod event;
use event::Envelope;

use std::sync::Arc;
use std::sync::mpsc;
use std::sync::mpsc::Sender;

use std::rc::Rc;
use std::cell::{Cell, RefCell};

use transformable_channels::mpsc::TransformableSender;

mod helpers;

#[macro_use]
extern crate log;

pub struct Tenquestionmarks {
    modules: BTreeMap<String, Module>
}

impl Tenquestionmarks {
    pub fn with_modules (modules: BTreeMap<String, Module>) -> Tenquestionmarks {
        let tqm = Tenquestionmarks {
            modules: modules
        };

        tqm
    }

    pub fn from_configuration (configuration: Table) -> Result<Tenquestionmarks, ModuleLoaderError> {
        let loader = ModuleLoader::new();
        let modules = loader.load_from_configuration(configuration)?;
        Result::Ok(Tenquestionmarks::with_modules(modules))
    }

    pub fn run (&self) {
        crossbeam::scope(|scope| {
            // Our main event channel.
            // Modules push events to tenquestionmarks using this channel.
            let (ref main_sender, ref main_receiver) = transformable_channels::mpsc::channel();

            // Module threads.
            // Each Module will produce events which tenquestionmarks will push
            // into all other Modules.
            // tenquestionmarks propagates all events to each Module through these
            // channels.
            let module_senders: BTreeMap<&str, Sender<Arc<Envelope>>> = self.modules.iter().map(|(key, module)| {
                let from = key.clone();
                let main_sender_mapped = main_sender.map(move |envelope: Envelope| {
                    Envelope {
                        from: Some(from.clone()),
                        event: envelope.event,
                        to: envelope.to,
                        tags: envelope.tags
                    }
                });

                let (module_sender, module_receiver) = mpsc::channel();
                info!("Spawning thread for \"{}\"", key);
                scope.spawn(move || {
                    module.run(Box::new(main_sender_mapped), module_receiver);
                    info!("Thread for \"{}\" is exiting", key);
                });
                (&key[..], module_sender)
            }).collect();

            // tenquestionmarks main event loop.
            // tenquestionmarks receives events produced by Modules and pushes them
            // into all other Modules
            loop {
                match main_receiver.recv() {
                    Ok(envelope) => {
                        /*
                         * Check if the target module is a valid destination for the envelope.
                         * We want to deliver this envelope if all of the following are true:
                         *    1. The target module is not the originator of the envelope
                         *    2. The envelope's list of allowed recipients is empty, or specifically
                         *       names the target module.
                         */
                        let arc_envelope = Arc::new(envelope);
                        for (key, sender) in &module_senders {
                            let from_this = String::from(*key);
                            match self.modules.get::<String>(&from_this) {
                                Some(module) => {
                                    if Some(from_this.clone()) == arc_envelope.from {
                                        debug!("Refusing to transmit event to its originator ({:?})", from_this);
                                        continue;
                                    }
                                    else if !(arc_envelope.to.is_empty() || !arc_envelope.to.contains(&from_this)) {
                                        debug!(
                                            "Refusing to transmit envelope from {:?} to {:?} since it is not on the list of allowed recipients ({:?})",
                                            arc_envelope.from,
                                            from_this,
                                            arc_envelope.to
                                        );
                                        continue;
                                    }
                                    else if !module.can_handle_event(&arc_envelope) {
                                        debug!(
                                            "Refusing to transmit envelope from {:?} to {:?} since envelope was filtered out",
                                            arc_envelope.from,
                                            from_this
                                        );
                                        continue;
                                    }

                                    match sender.send(arc_envelope.clone()) {
                                        Err(err) => debug!("Failed to dispatch event to module \"{}\": {:?}", key, err),
                                        Ok(_) => {}
                                    }
                                },
                                None => debug!("Failed to dispatch event to module \"{}\": No such module found!", key)
                            }
                        }
                    },
                    Err(err) => { error!("Failed to receive event in main event loop: {:?}", err); }
                }
            }
        });
    }
}

#[derive(Debug)]
pub struct Message {
    content: String,
    author: User,
    channel: Option<Channel>
}

impl Message {
    fn reply (&self, message: &str) {
        match self.channel {
            Some(ref channel) => channel.send(message),
            None => self.author.send(message)
        }
    }
}

#[derive(Debug)]
pub struct Channel {
    name: String,
    description: String,
    topic: String,
    sender: Box<MessageSender>
}

impl Channel {
    pub fn send (&self, message: &str) {
        self.sender.send_message(message);
    }
}

#[derive(Debug)]
pub struct User {
    name: String,
    sender: Box<MessageSender>
}

impl User {
    pub fn send (&self, message: &str) {
        self.sender.send_message(message);
    }
}

pub trait MessageSender : Sync + Send + std::fmt::Debug {
    fn send_message (&self, _: &str) {}
}