use crate::*;
use opener::open;

macro_rules! press {
    (Shift-$($key:tt)+) => {
        Event::Key(KeyEvent {
            code:      KeyCode::$($key)+,
            kind:      KeyEventKind::Press,
            modifiers: KeyModifiers::SHIFT,
            state:     KeyEventState::NONE
        })
    };
    ($($key:tt)+) => {
        Event::Key(KeyEvent {
            code:      KeyCode::$($key)+,
            kind:      KeyEventKind::Press,
            modifiers: KeyModifiers::NONE,
            state:     KeyEventState::NONE
        })
    };
}

mod edit; pub use self::edit::*;
mod save; pub use self::save::*;
mod quit; pub use self::quit::*;

impl Handle<TuiIn> for Taggart {
    fn handle (&mut self, input: &TuiIn) -> Perhaps<bool> {
        let min = self.offset;
        let max = self.offset + self.display.h().saturating_sub(1);
        let event = &*input.event();
        match &self.mode {
            Some(Mode::Edit { .. }) => self.mode_edit(event),
            Some(Mode::Save { value }) => self.mode_save(event, *value),
            Some(Mode::Quit { value }) => self.mode_quit(event, *value),
            None => match event {
                press!(Char('q')) => { self.quit_begin(&input) },
                press!(Char('w')) => { self.save_begin() },
                press!(Enter)     => { self.edit_begin() },
                press!(Up)        => { self.cursor = self.cursor.saturating_sub(1); },
                press!(Down)      => { self.cursor = self.cursor + 1; },
                press!(PageUp)    => { self.cursor = self.cursor.saturating_sub(PAGE_SIZE); },
                press!(PageDown)  => { self.cursor += PAGE_SIZE; },
                press!(Left)      => { self.column = self.column.saturating_sub(1); },
                press!(Right)     => { self.column = self.column + 1; },
                press!(Char(' ')) => { open(self.entries[self.cursor].path.as_ref())?; }
                press!(Char(']')) => { self.columns.0[self.column].width += 1; }
                press!(Char('[')) => { self.columns.0[self.column].width =
                    self.columns.0[self.column].width.saturating_sub(1).max(5); }
                _ => {}
            }
            _ => todo!("{:?}", self.mode)
        }
        self.clamp(min, max);
        Ok(None)
    }
}

impl Taggart {
    fn clamp (&mut self, min: usize, max: usize) {
        if self.cursor < min {
            self.offset = self.cursor;
        }
        if self.cursor > max {
            self.offset += self.cursor - max;
        }
        if self.offset > self.entries.len().saturating_sub(self.display.h()) {
            self.offset = self.entries.len().saturating_sub(self.display.h())
        }
        if self.cursor >= self.entries.len() {
            self.cursor = self.entries.len().saturating_sub(1)
        }
        if self.column + 1 > self.columns.0.len() {
            self.column = self.columns.0.len().saturating_sub(1)
        }
    }
}