use ::{
    std::{io::stdout, sync::{Arc, RwLock}},
    ratatui::style::Color,
    tengri::{*, lang::*},
};

tui_main!(State {
    cursor: 0,
    ..Default::default()
});

tui_keys!(|self: State, input| {
    Ok(())
});

tui_view!(|self: State| {
    let index   = self.cursor + 1;
    let wh      = (self.size.w(), self.size.h());
    let src     = VIEWS.get(self.cursor).unwrap_or(&"");
    let heading = format!("State {}/{} in {:?}", index, VIEWS.len(), &wh);
    let title   = bg(Color::Rgb(60, 10, 10), heading.align_n().push_y(1));
    let code    = bg(Color::Rgb(10, 60, 10), format!("{}", src).align_n().push_y(2));
    let widget  = thunk(move|to: &mut Tui|self.interpret(to, &src));
    self.size.of(south(title, north(code, widget)))
});

#[dizzle::namespace(bool)]
#[dizzle::namespace(u16)]
#[dizzle::namespace(Option<u16>)]
#[dizzle::namespace(Color)]
#[derive(Debug, Default)]
struct State {
    /** Command history (undo/redo). */
    history: Vec<Action>,
    /** User-controllable value. */
    cursor: usize,
    /** Rendered window size. */
    size: Sizer,
}

impl Interpret<Tui, Option<XYWH<u16>>> for State {
    fn interpret_word <'a> (&'a self, to: &mut Tui, lang: &'a impl Symbol) -> Drawn<u16> {
        match lang.src()? {
            Some(":hello") => "hello".draw(to),
            Some(":world") => "world".draw(to),
            Some(":hello-world") => "Hello World!".draw(to),
            _ => todo!()
        }
    }
    fn interpret_expr <'a> (&'a self, to: &mut Tui, lang: &'a impl Expression) -> Drawn<u16> {
        Ok(Some(if let Some(area) = eval_view(self, to, lang)? {
            area
        } else if let Some(area) = eval_view_tui(self, to, lang)? {
            area
        } else {
            return Err(format!("App::interpret_expr: unexpected: {lang:?}").into())
        }))
    }
}

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

impl Action {

    const BINDS: &'static str = stringify! {
        (@left  prev)
        (@right next)
    };

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

    fn next (state: &mut State) -> Perhaps<Self> {
        state.cursor = (state.cursor + 1) % VIEWS.len();
        Ok(Some(Self::Prev))
    }

    fn prev (state: &mut State) -> Perhaps<Self> {
        state.cursor = if state.cursor > 0 { state.cursor - 1 } else { VIEWS.len() - 1 };
        Ok(Some(Self::Next))
    }

}

const VIEWS: &'static [&'static str] = &[

    stringify! { :hello-world },

    stringify! { (fill/xy :hello-world) },

    stringify! { (bsp/s :hello :world) },

    stringify! { (fixed/xy 20 10 :hello-world) },

    stringify! { (bsp/s (fixed/xy 5 6 :hello) (fixed/xy 7 8 :world)) },

    stringify! { (bsp/e (fixed/xy 5 6 :hello) (fixed/xy 7 8 :world)) },

    stringify! { (bsp/n (fixed/xy 5 6 :hello) (fixed/xy 7 8 :world)) },

    stringify! { (bsp/w (fixed/xy 5 6 :hello) (fixed/xy 7 8 :world)) },

    stringify! { (bsp/a (fixed/xy 5 6 :hello) (fixed/xy 7 8 :world)) },

    stringify! { (bsp/b (fixed/xy 5 6 :hello) (fixed/xy 7 8 :world)) },

    stringify! {
        (bsp/s
          (bsp/e       (align/nw (fixed/xy 5 3 :hello))
            (bsp/e     (align/n  (fixed/xy 5 3 :hello))
                       (align/ne (fixed/xy 5 3 :hello))))
            (bsp/s
              (bsp/e   (align/w  (fixed/xy 5 3 :hello))
                (bsp/e (align/c  (fixed/xy 5 3 :hello))
                       (align/e  (fixed/xy 5 3 :hello))))
              (bsp/e   (align/sw (fixed/xy 5 3 :hello))
                (bsp/e (align/s  (fixed/xy 5 3 :hello))
                       (align/se (fixed/xy 5 3 :hello))))))
    },

    stringify! {
        (bsp/s
          (bsp/e     (fixed/xy 8 5 (align/nw :hello))
            (bsp/e   (fixed/xy 8 5 (align/n  :hello))
                     (fixed/xy 8 5 (align/ne :hello))))
          (bsp/s
            (bsp/e   (fixed/xy 8 5 (align/w  :hello))
              (bsp/e (fixed/xy 8 5 (align/c  :hello))
                     (fixed/xy 8 5 (align/e  :hello))))
            (bsp/e   (fixed/xy 8 5 (align/sw :hello))
              (bsp/e (fixed/xy 8 5 (align/s  :hello))
                     (fixed/xy 8 5 (align/se :hello))))))
    },

    stringify! {
        (bsp/s
          (bsp/e     (grow/xy 1 1 (fixed/xy 8 5 (align/nw :hello)))
            (bsp/e   (grow/xy 1 1 (fixed/xy 8 5 (align/n  :hello)))
                     (grow/xy 1 1 (fixed/xy 8 5 (align/ne :hello)))))
          (bsp/s
            (bsp/e   (grow/xy 1 1 (fixed/xy 8 5 (align/w  :hello)))
              (bsp/e (grow/xy 1 1 (fixed/xy 8 5 (align/c  :hello)))
                     (grow/xy 1 1 (fixed/xy 8 5 (align/e  :hello)))))
            (bsp/e   (grow/xy 1 1 (fixed/xy 8 5 (align/sw :hello)))
              (bsp/e (grow/xy 1 1 (fixed/xy 8 5 (align/s  :hello)))
                     (grow/xy 1 1 (fixed/xy 8 5 (align/se :hello)))))))
    },

    stringify! { :map-e },

    stringify! { (align/c :map-e) },

    stringify! { :map-s },

    stringify! { (align/c :map-s) },

    stringify! {
        (align/c (bg/behind :bg0 (margin/xy 1 1 (col
          (bg/behind :bg1 (border/around :border1 (margin/xy 2 1 :label1)))
          (bg/behind :bg2 (border/around :border2 (margin/xy 4 2 :label2)))
          (bg/behind :bg3 (border/around :border3 (margin/xy 6 3 :label3)))))))
    },

];

   //handle!(TuiIn: |self: State, input|Action::from(input).eval(self).map(|_|None));
     //view!(State: Tui: [ evaluate_output_expression, evaluate_output_expression_tui ]);
     //draw!(State: Tui: [ draw_example ]);

//impl_from!(Action: |input: &TuiIn| todo!());

//fn draw_example (state: &State, to: &mut Tui) {
//}