tengri/examples/mode_01.rs

//! Mode 01: Direct view, actions with history

use itertools::Itertools;
use ::tengri::{
    *,
    lang::*,
    crossterm::event::{Event::*, KeyEvent, KeyCode::*},
    ratatui::style::Color,
};

tui_app!(State {
    /** Command history (undo/redo). */
    history: Vec<Action>,
    /** User-controllable value. */
    cursor:  usize,
});

tui_keys!(self: State, input {
    Ok(if let Key(KeyEvent { code, .. }) = input.0 {
        match code {
            Down | Right => Action::Next,
            Up   | Left  => Action::Prev,
            _ => { return Ok(()) }
        }
            .apply(self)?
            .map(|x|self.history.push(x));
    })
});

tui_view!(self: State {
    let title   = "Demo Mode 00";
    let items   = self.history.iter().take(10).map(|x|format!("{x:?}")).join("\n");
    let history = format!("History: {}\n{items}", self.history.len());
    let cursor  = format!("Counter:  {}", self.cursor);
    north(
        east(title.align_sw(), ShowSize.align_se()),
        east(history.align_c(), cursor.align_c()),
    )
});

#[derive(Debug)] enum Action {
    /** Increment cursor */ Next,
    /** Decrement cursor */ Prev,
}

impl Action {
    fn apply (&self, state: &mut State) -> Perhaps<Self> {
        use Action::*;
        match self {
            Next => state.next(),
            Prev => state.prev(),
        }
    }
}

impl State {
    fn next (&mut self) -> Perhaps<Action> {
        self.cursor = (self.cursor + 1) % 10;
        Ok(Some(Action::Prev))
    }
    fn prev (&mut self) -> Perhaps<Action> {
        self.cursor = if self.cursor > 0 { self.cursor - 1 } else { 10 - 1 };
        Ok(Some(Action::Next))
    }
}