use crate::*;

#[derive(Clone, PartialEq)]
pub enum SequencerAppCommand {
    Focus(FocusCommand),
    Transport(TransportCommand),
    Phrases(PhrasePoolCommand),
    Editor(PhraseEditorCommand),
}

impl Handle<Tui> for SequencerApp<Tui> {
    fn handle (&mut self, i: &TuiInput) -> Perhaps<bool> {
        if let Some(entered) = self.entered() {
            use SequencerFocus::*;
            if let Some(true) = match entered {
                Transport    => self.transport.as_mut().map(|t|t.handle(i)).transpose()?.flatten(),
                PhrasePool   => self.phrases.write().unwrap().handle(i)?,
                PhraseEditor => self.editor.handle(i)?,
            } {
                return Ok(Some(true))
            }
        }
        if let Some(command) = SequencerCommand::input_to_command(self, i) {
            let _undo = command.execute(self)?;
            return Ok(Some(true))
        }
        Ok(None)
    }
}

impl<E: Engine> Command<SequencerApp<E>> for SequencerAppCommand {
    fn execute (self, state: &mut SequencerApp<E>) -> Perhaps<Self> {
        match self {
            Self::Focus(cmd) => {
                return delegate(cmd, Self::Focus,     state)
            },
            Self::Phrases(cmd) => {
                return delegate(cmd, Self::Phrases,   &mut*state.phrases.write().unwrap())
            },
            Self::Editor(cmd) => {
                return delegate(cmd, Self::Editor,    &mut state.editor)
            },
            Self::Transport(cmd) => if let Some(ref transport) = state.transport {
                return delegate(cmd, Self::Transport, &mut*transport.write().unwrap())
            },
        }
        Ok(None)
    }
}

impl InputToCommand<Tui, SequencerApp<Tui>> for SequencerCommand {
    fn input_to_command (state: &SequencerApp<Tui>, input: &TuiInput) -> Option<Self> {
        use SequencerCommand::*;
        use FocusCommand::*;
        match input.event() {
            key!(KeyCode::Tab)           => Some(Focus(Next)),
            key!(Shift-KeyCode::Tab)     => Some(Focus(Prev)),
            key!(KeyCode::BackTab)       => Some(Focus(Prev)),
            key!(Shift-KeyCode::BackTab) => Some(Focus(Prev)),
            key!(KeyCode::Up)            => Some(Focus(Up)),
            key!(KeyCode::Down)          => Some(Focus(Down)),
            key!(KeyCode::Left)          => Some(Focus(Left)),
            key!(KeyCode::Right)         => Some(Focus(Right)),
            key!(KeyCode::Char(' '))     => Some(Transport(TransportCommand::PlayToggle)),
            _ => match state.focused() {
                SequencerFocus::Transport => if let Some(t) = state.transport.as_ref() {
                    TransportCommand::input_to_command(&*t.read().unwrap(), input).map(Transport)
                } else {
                    None
                },
                SequencerFocus::PhrasePool =>
                    PhrasePoolCommand::input_to_command(&*state.phrases.read().unwrap(), input)
                        .map(Phrases),
                SequencerFocus::PhraseEditor =>
                    PhraseEditorCommand::input_to_command(&state.editor, input)
                        .map(Editor),
            }
        }
    }
}