use errors::*;
use glib;
use std::cell::Cell;
use std::cell::Ref;
use std::cell::RefCell;
use std::rc::Rc;
use std::f64;
use alsa_pn::*;



#[derive(Clone, Copy, Debug)]
pub enum AudioUser {
    AudioUserUnknown,
    AudioUserPopup,
    AudioUserTrayIcon,
    AudioUserHotkeys,
}


#[derive(Clone, Copy, Debug)]
pub enum AudioSignal {
    AudioNoCard,
    AudioCardInitialized,
    AudioCardCleanedUp,
    AudioCardDisconnected,
    AudioCardError,
    AudioValuesChanged,
}


#[derive(Clone)]
pub struct Handlers {
    inner: Rc<RefCell<Vec<Box<Fn(AudioSignal, AudioUser)>>>>,
}


impl Handlers {
    fn new() -> Handlers {
        return Handlers { inner: Rc::new(RefCell::new(vec![])) };
    }


    fn borrow(&self) -> Ref<Vec<Box<Fn(AudioSignal, AudioUser)>>> {
        return self.inner.borrow();
    }


    fn add_handler(&self, cb: Box<Fn(AudioSignal, AudioUser)>) {
        self.inner.borrow_mut().push(cb);
    }
}


pub struct Audio {
    _cannot_construct: (),
    pub acard: RefCell<Box<AlsaCard>>,
    pub last_action_timestamp: Rc<RefCell<i64>>,
    pub handlers: Handlers,
    pub scroll_step: Cell<u32>,
}


impl Audio {
    pub fn new(card_name: Option<String>,
               elem_name: Option<String>)
               -> Result<Audio> {

        let handlers = Handlers::new();
        let last_action_timestamp = Rc::new(RefCell::new(0));

        let cb = {
            let myhandler = handlers.clone();
            let ts = last_action_timestamp.clone();
            Rc::new(move |event| {
                        on_alsa_event(&mut *ts.borrow_mut(),
                                      &myhandler.borrow(),
                                      event)
                    })
        };

        let audio = Audio {
            _cannot_construct: (),
            acard: RefCell::new(AlsaCard::new(card_name, elem_name, cb)?),
            last_action_timestamp: last_action_timestamp.clone(),
            handlers: handlers.clone(),
            scroll_step: Cell::new(5),
        };

        return Ok(audio);
    }


    pub fn switch_acard(&self,
                        card_name: Option<String>,
                        elem_name: Option<String>)
                        -> Result<()> {
        debug!("Switching cards");
        debug!("Old card name: {}",
               self.acard
                   .borrow()
                   .card_name()
                   .unwrap());
        debug!("Old chan name: {}",
               self.acard
                   .borrow()
                   .chan_name()
                   .unwrap());
        let cb = self.acard
            .borrow()
            .cb
            .clone();
        {
            let mut ac = self.acard.borrow_mut();
            *ac = AlsaCard::new(card_name, elem_name, cb)?;
        }
        debug!("Old card name: {}",
               self.acard
                   .borrow()
                   .card_name()
                   .unwrap());
        debug!("Old chan name: {}",
               self.acard
                   .borrow()
                   .chan_name()
                   .unwrap());
        return Ok(());
    }


    pub fn vol(&self) -> Result<f64> {
        return self.acard.borrow().get_vol();
    }


    pub fn set_vol(&self, new_vol: f64, user: AudioUser) -> Result<()> {
        {
            let mut rc = self.last_action_timestamp.borrow_mut();
            *rc = glib::get_monotonic_time();
        }
        // TODO invoke handlers, make use of user

        debug!("Setting vol on card {:?} and chan {:?} to {:?} by user {:?}",
               self.acard
                   .borrow()
                   .card_name()
                   .unwrap(),
               self.acard
                   .borrow()
                   .chan_name()
                   .unwrap(),
               new_vol,
               user);
        return self.acard.borrow().set_vol(new_vol);
    }


    pub fn increase_vol(&self, user: AudioUser) -> Result<()> {
        {
            let mut rc = self.last_action_timestamp.borrow_mut();
            *rc = glib::get_monotonic_time();
        }
        let old_vol = self.vol()?;
        let new_vol = f64::ceil(old_vol + (self.scroll_step.get() as f64));

        debug!("Increase vol on card {:?} and chan {:?} by {:?} to {:?}",
               self.acard
                   .borrow()
                   .card_name()
                   .unwrap(),
               self.acard
                   .borrow()
                   .chan_name()
                   .unwrap(),
               (new_vol - old_vol),
               new_vol);

        return self.set_vol(new_vol, user);
    }


    pub fn decrease_vol(&self, user: AudioUser) -> Result<()> {
        {
            let mut rc = self.last_action_timestamp.borrow_mut();
            *rc = glib::get_monotonic_time();
        }
        let old_vol = self.vol()?;
        let new_vol = old_vol - (self.scroll_step.get() as f64);

        debug!("Decrease vol on card {:?} and chan {:?} by {:?} to {:?}",
               self.acard
                   .borrow()
                   .card_name()
                   .unwrap(),
               self.acard
                   .borrow()
                   .chan_name()
                   .unwrap(),
               (new_vol - old_vol),
               new_vol);

        return self.set_vol(new_vol, user);
    }


    pub fn has_mute(&self) -> bool {
        return self.acard.borrow().has_mute();
    }


    pub fn get_mute(&self) -> Result<bool> {
        return self.acard.borrow().get_mute();
    }


    pub fn set_mute(&self, mute: bool, user: AudioUser) -> Result<()> {
        let mut rc = self.last_action_timestamp.borrow_mut();
        *rc = glib::get_monotonic_time();
        // TODO invoke handlers, make use of user

        debug!("Setting mute to {} on card {:?} and chan {:?} by user {:?}",
               mute,
               self.acard
                   .borrow()
                   .card_name()
                   .unwrap(),
               self.acard
                   .borrow()
                   .chan_name()
                   .unwrap(),
               user);

        return self.acard.borrow().set_mute(mute);
    }


    pub fn connect_handler(&self, cb: Box<Fn(AudioSignal, AudioUser)>) {
        self.handlers.add_handler(cb);
    }
}


fn invoke_handlers(handlers: &Vec<Box<Fn(AudioSignal, AudioUser)>>,
                   signal: AudioSignal,
                   user: AudioUser) {
    debug!("Invoking handlers for signal {:?} by user {:?}",
           signal,
           user);
    for handler in handlers {
        let unboxed = handler.as_ref();
        unboxed(signal, user);
    }
}


fn on_alsa_event(last_action_timestamp: &mut i64,
                 handlers: &Vec<Box<Fn(AudioSignal, AudioUser)>>,
                 alsa_event: AlsaEvent) {
    let last: i64 = *last_action_timestamp;

    debug!("Last: {}", last);

    if last != 0 {
        let now: i64 = glib::get_monotonic_time();
        let delay: i64 = now - last;
        if delay < 1000000 {
            return;
        }
        debug!("Discarding last time stamp, too old");
        *last_action_timestamp = 0;
    }

    /* external change */
    match alsa_event {
        // TODO: invoke handlers with AudioUserUnknown
        AlsaEvent::AlsaCardError => debug!("AlsaCardError"),
        AlsaEvent::AlsaCardDiconnected => debug!("AlsaCardDiconnected"),
        AlsaEvent::AlsaCardValuesChanged => {
            debug!("AlsaCardValuesChanged");
            invoke_handlers(handlers,
                            self::AudioSignal::AudioValuesChanged,
                            self::AudioUser::AudioUserUnknown);
        }
        e => warn!("Unhandled alsa event: {:?}", e),
    }

}