use crate::*;

#[derive(Clone, PartialEq)]
enum SequencerCommand {
    FocusNext,
    FocusPrev,
    FocusUp,
    FocusDown,
    FocusLeft,
    FocusRight,
    Transport(TransportCommand),
    Phrases(PhrasePoolCommand),
    Editor(PhraseEditorCommand),
}
#[derive(Clone, PartialEq)]
pub enum PhrasePoolCommand {
    Previous,
    Next,
    MoveUp,
    MoveDown,
    Delete,
    Append,
    Insert,
    Duplicate,
    RandomColor,
    Edit,
    Rename(PhraseRenameCommand),
    Length(PhraseLengthCommand),
}
#[derive(Clone, PartialEq)]
pub enum PhraseRenameCommand {
    Begin,
    Backspace,
    Append(char),
    Set(String),
    Confirm,
    Cancel,
}
#[derive(Clone, PartialEq)]
pub enum PhraseLengthCommand {
    Begin,
    Next,
    Previous,
    Increment,
    Decrement,
    Set(usize),
    Confirm,
    Cancel,
}
#[derive(Clone, PartialEq)]
pub enum PhraseEditorCommand {
    // TODO: 1-9 seek markers that by default start every 8th of the phrase
    ToggleDirection,
    EnterEditMode,
    ExitEditMode,
    NoteLengthDecrement,
    NoteLengthIncrement,
    TimeZoomIn,
    TimeZoomOut,
    NoteAppend,
    NoteSet,
    NotePageUp,
    NotePageDown,
    GoUp,
    GoDown,
    GoLeft,
    GoRight,
}
impl HandleKey<SequencerCommand> for Sequencer<Tui> {
    fn match_input (&self, from: &TuiInput) -> Option<SequencerCommand> {
        match from.event() {
            key!(KeyCode::Tab)           => Some(SequencerCommand::FocusNext),
            key!(Shift-KeyCode::Tab)     => Some(SequencerCommand::FocusPrev),
            key!(KeyCode::BackTab)       => Some(SequencerCommand::FocusPrev),
            key!(Shift-KeyCode::BackTab) => Some(SequencerCommand::FocusPrev),
            key!(KeyCode::Up)            => Some(SequencerCommand::FocusUp),
            key!(KeyCode::Down)          => Some(SequencerCommand::FocusDown),
            key!(KeyCode::Left)          => Some(SequencerCommand::FocusLeft),
            key!(KeyCode::Right)         => Some(SequencerCommand::FocusRight),
            key!(KeyCode::Char(' '))     => Some(SequencerCommand::Transport(
                TransportCommand::TogglePlay)), // FIXME go through transport
            _ => match self.focused() {
                SequencerFocus::Transport => self.transport.as_ref()
                    .map(|t|t.read().unwrap().match_input(from).map(SequencerCommand::Transport))
                    .flatten(),
                SequencerFocus::PhrasePool => self.phrases.read().unwrap()
                    .match_input(from)
                    .map(SequencerCommand::Phrases),
                SequencerFocus::PhraseEditor => self.editor
                    .match_input(from)
                    .map(SequencerCommand::Editor),
            }
        }
    }
}
impl HandleKey<PhrasePoolCommand> for PhrasePool<Tui> {
    fn match_input (&self, from: &TuiInput) -> Option<PhrasePoolCommand> {
        match from.event() {
            key!(KeyCode::Up)        => Some(PhrasePoolCommand::Previous),
            key!(KeyCode::Down)      => Some(PhrasePoolCommand::Next),
            key!(KeyCode::Char(',')) => Some(PhrasePoolCommand::MoveUp),
            key!(KeyCode::Char('.')) => Some(PhrasePoolCommand::MoveDown),
            key!(KeyCode::Delete)    => Some(PhrasePoolCommand::Delete),
            key!(KeyCode::Char('a')) => Some(PhrasePoolCommand::Append),
            key!(KeyCode::Char('i')) => Some(PhrasePoolCommand::Insert),
            key!(KeyCode::Char('d')) => Some(PhrasePoolCommand::Duplicate),
            key!(KeyCode::Char('c')) => Some(PhrasePoolCommand::RandomColor),
            key!(KeyCode::Char('n')) => Some(PhrasePoolCommand::Rename(PhraseRenameCommand::Begin)),
            key!(KeyCode::Char('t')) => Some(PhrasePoolCommand::Length(PhraseLengthCommand::Begin)),
            _ => match self.mode {
                Some(PhrasePoolMode::Rename(..)) => HandleKey::<PhraseRenameCommand>
                    ::match_input(self, from).map(PhrasePoolCommand::Rename),
                Some(PhrasePoolMode::Length(..)) => HandleKey::<PhraseLengthCommand>
                    ::match_input(self, from).map(PhrasePoolCommand::Length),
                _ => None
            }
        }
    }
}
impl HandleKey<PhraseRenameCommand> for PhrasePool<Tui> {
    fn match_input (&self, from: &TuiInput) -> Option<PhraseRenameCommand> {
        match from.event() {
            key!(KeyCode::Backspace) => Some(PhraseRenameCommand::Backspace),
            key!(KeyCode::Enter)     => Some(PhraseRenameCommand::Confirm),
            key!(KeyCode::Esc)       => Some(PhraseRenameCommand::Cancel),
            key!(KeyCode::Char(c))   => Some(PhraseRenameCommand::Append(*c)),
            _ => None
        }
    }
}
impl HandleKey<PhraseLengthCommand> for PhrasePool<Tui> {
    fn match_input (&self, from: &TuiInput) -> Option<PhraseLengthCommand> {
        match from.event() {
            key!(KeyCode::Up)    => Some(PhraseLengthCommand::Increment),
            key!(KeyCode::Down)  => Some(PhraseLengthCommand::Decrement),
            key!(KeyCode::Right) => Some(PhraseLengthCommand::Next),
            key!(KeyCode::Left)  => Some(PhraseLengthCommand::Previous),
            key!(KeyCode::Enter) => Some(PhraseLengthCommand::Confirm),
            key!(KeyCode::Esc)   => Some(PhraseLengthCommand::Cancel),
            _ => None
        }
    }
}
impl HandleKey<PhraseEditorCommand> for PhraseEditor<Tui> {
    fn match_input (&self, from: &TuiInput) -> Option<PhraseEditorCommand> {
        match from.event() {
            key!(KeyCode::Char('`')) => Some(PhraseEditorCommand::ToggleDirection),
            key!(KeyCode::Enter)     => Some(PhraseEditorCommand::EnterEditMode),
            key!(KeyCode::Esc)       => Some(PhraseEditorCommand::ExitEditMode),
            key!(KeyCode::Char('[')) => Some(PhraseEditorCommand::NoteLengthDecrement),
            key!(KeyCode::Char(']')) => Some(PhraseEditorCommand::NoteLengthIncrement),
            key!(KeyCode::Char('a')) => Some(PhraseEditorCommand::NoteAppend),
            key!(KeyCode::Char('s')) => Some(PhraseEditorCommand::NoteSet),
            key!(KeyCode::Char('-')) => Some(PhraseEditorCommand::TimeZoomOut),
            key!(KeyCode::Char('_')) => Some(PhraseEditorCommand::TimeZoomOut),
            key!(KeyCode::Char('=')) => Some(PhraseEditorCommand::TimeZoomIn),
            key!(KeyCode::Char('+')) => Some(PhraseEditorCommand::TimeZoomIn),
            key!(KeyCode::PageUp)    => Some(PhraseEditorCommand::NotePageUp),
            key!(KeyCode::PageDown)  => Some(PhraseEditorCommand::NotePageDown),
            key!(KeyCode::Up)        => Some(PhraseEditorCommand::GoUp),
            key!(KeyCode::Down)      => Some(PhraseEditorCommand::GoDown),
            key!(KeyCode::Left)      => Some(PhraseEditorCommand::GoLeft),
            key!(KeyCode::Right)     => Some(PhraseEditorCommand::GoRight),
            _ => None
        }
    }
}
/// Handle top-level events in standalone sequencer.
impl Handle<Tui> for Sequencer<Tui> {
    fn handle (&mut self, from: &TuiInput) -> Perhaps<bool> {
        if let Some(command) = self.match_input(from) {
            let _undo = command.run(self)?;
            return Ok(Some(true))
        }
        Ok(None)
    }
}
impl Handle<Tui> for PhrasePool<Tui> {
    fn handle (&mut self, from: &TuiInput) -> Perhaps<bool> {
        if let Some(command) = HandleKey::<PhrasePoolCommand>::match_input(self, from) {
            let _undo = command.run(self)?;
            return Ok(Some(true))
        }
        Ok(None)
    }
}
impl Handle<Tui> for PhraseEditor<Tui> {
    fn handle (&mut self, from: &TuiInput) -> Perhaps<bool> {
        if let Some(command) = self.match_input(from) {
            let _undo = command.run(self)?;
            return Ok(Some(true))
        }
        Ok(None)
    }
}
impl<E: Engine> Command<Sequencer<E>> for SequencerCommand {
    fn run (&self, state: &mut Sequencer<E>) -> Perhaps<Self> {
        match self {
            Self::FocusNext  => { state.focus_next(); },
            Self::FocusPrev  => { state.focus_prev(); },
            Self::FocusUp    => { state.focus_up(); },
            Self::FocusDown  => { state.focus_down(); },
            Self::FocusLeft  => { state.focus_left(); },
            Self::FocusRight => { state.focus_right(); },
            Self::Transport(command) => if let Some(ref transport) = state.transport {
                return command
                    .run(&mut*transport.write().unwrap())
                    .map(|x|x.map(SequencerCommand::Transport))
            },
            Self::Phrases(command) => {
                return command
                    .run(&mut*state.phrases.write().unwrap())
                    .map(|x|x.map(SequencerCommand::Phrases))
            },
            Self::Editor(command) => {
                return command
                    .run(&mut state.editor)
                    .map(|x|x.map(SequencerCommand::Editor))
            },
        }
        Ok(None)
    }
}
impl<E: Engine> Command<PhrasePool<E>> for PhrasePoolCommand {
    fn run (&self, state: &mut PhrasePool<E>) -> Perhaps<Self> {
        match self {
            Self::Previous => {
                state.select_prev()
            },
            Self::Next => {
                state.select_next()
            },
            Self::Delete => {
                state.delete_selected()
            },
            Self::Append => {
                state.append_new(None, None)
            },
            Self::Insert => {
                state.insert_new(None, None)
            },
            Self::Duplicate => {
                state.insert_dup()
            },
            Self::Edit => {
                todo!();
            }
            Self::RandomColor => {
                state.randomize_color()
            },
            Self::MoveUp => {
                state.move_up()
            },
            Self::MoveDown => {
                state.move_down()
            },
            Self::Rename(PhraseRenameCommand::Begin) => {
                state.begin_rename()
            },
            Self::Rename(_) => {
                unreachable!()
            },
            Self::Length(PhraseLengthCommand::Begin) => {
                state.begin_length()
            },
            Self::Length(_) => {
                unreachable!()
            },
        }
        Ok(None)
    }
}
impl<E: Engine> Command<PhrasePool<E>> for PhraseRenameCommand {
    fn run (&self, state: &mut PhrasePool<E>) -> Perhaps<Self> {
        if let Some(PhrasePoolMode::Rename(phrase, ref mut old_name)) = state.mode {
            match self {
                Self::Begin => {
                    unreachable!();
                },
                Self::Backspace => {
                    let mut phrase = state.phrases[phrase].write().unwrap();
                    let old_name = phrase.name.clone();
                    phrase.name.pop();
                    return Ok(Some(Self::Set(old_name)))
                },
                Self::Append(c) => {
                    let mut phrase = state.phrases[phrase].write().unwrap();
                    let old_name = phrase.name.clone();
                    phrase.name.push(*c);
                    return Ok(Some(Self::Set(old_name)))
                },
                Self::Set(s) => {
                    let mut phrase = state.phrases[phrase].write().unwrap();
                    phrase.name = s.into();
                    return Ok(Some(Self::Set(old_name.clone())))
                },
                Self::Confirm => {
                    let old_name = old_name.clone();
                    state.mode = None;
                    return Ok(Some(Self::Set(old_name)))
                },
                Self::Cancel => {
                    let mut phrase = state.phrases[phrase].write().unwrap();
                    phrase.name = old_name.clone();
                }
            };
            Ok(None)
        } else if *self == Self::Begin {
            todo!()
        } else {
            unreachable!()
        }
    }
}
impl<E: Engine> Command<PhrasePool<E>> for PhraseLengthCommand {
    fn run (&self, state: &mut PhrasePool<E>) -> Perhaps<Self> {
        if let Some(PhrasePoolMode::Length(phrase, ref mut length, ref mut focus)) = state.mode {
            match self {
                Self::Begin => {
                    unreachable!();
                },
                Self::Previous => {
                    focus.prev()
                },
                Self::Next => {
                    focus.next()
                },
                Self::Increment => match focus {
                    PhraseLengthFocus::Bar  => {
                        *length += 4 * PPQ
                    },
                    PhraseLengthFocus::Beat => {
                        *length += PPQ
                    },
                    PhraseLengthFocus::Tick => {
                        *length += 1
                    },
                },
                Self::Decrement => match focus {
                    PhraseLengthFocus::Bar  => {
                        *length = length.saturating_sub(4 * PPQ)
                    },
                    PhraseLengthFocus::Beat => {
                        *length = length.saturating_sub(PPQ)
                    },
                    PhraseLengthFocus::Tick => {
                        *length = length.saturating_sub(1)
                    },
                },
                Self::Cancel => {
                    state.mode = None;
                },
                Self::Confirm => {
                    return Self::Set(*length).run(state)
                },
                Self::Set(length) => {
                    let mut phrase = state.phrases[phrase].write().unwrap();
                    let old_length = phrase.length;
                    phrase.length = *length;
                    state.mode = None;
                    return Ok(Some(Self::Set(old_length)))
                },
            }
            Ok(None)
        } else if *self == Self::Begin {
            todo!()
        } else {
            unreachable!()
        }
    }
}
impl<E: Engine> Command<PhraseEditor<E>> for PhraseEditorCommand {
    fn run (&self, state: &mut PhraseEditor<E>) -> Perhaps<Self> {
        match self {
            Self::ToggleDirection => {
                state.mode = !state.mode;
            },
            Self::EnterEditMode => {
                state.entered = true;
            },
            Self::ExitEditMode => {
                state.entered = false;
            },
            Self::TimeZoomOut => {
                state.time_zoom_out()
            },
            Self::TimeZoomIn => {
                state.time_zoom_in()
            },
            Self::NoteLengthDecrement => {
                state.note_length_dec()
            },
            Self::NoteLengthIncrement => {
                state.note_length_inc()
            },
            Self::NotePageUp => {
                state.note_page_up()
            },
            Self::NotePageDown => {
                state.note_page_down()
            },
            Self::NoteAppend => if state.entered {
                state.put();
                state.time_cursor_advance();
            },
            Self::NoteSet => if state.entered {
                state.put();
            },
            Self::GoUp => match state.entered {
                true  => state.note_cursor_inc(),
                false => state.note_scroll_inc(),
            },
            Self::GoDown => match state.entered {
                true  => state.note_cursor_dec(),
                false => state.note_scroll_dec(),
            },
            Self::GoLeft => match state.entered {
                true  => state.time_cursor_dec(),
                false => state.time_scroll_dec(),
            },
            Self::GoRight => match state.entered {
                true  => state.time_cursor_inc(),
                false => state.time_scroll_inc(),
            },
        }
        Ok(None)
    }
}