//! Mode 02: Inline Dizzle config

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,
    /** Rendered window size. */
    size:    Sizer,
});

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_xy(2, 1)).exact_h(3);
    let code    = bg(Color::Rgb(10, 60, 10), format!("Source:\n{}", src).align_n().push_xy(2, 1)).min_h(4);
    let widget  = thunk(move|to: &mut Tui|self.interpret(to, &src));
    self.size.of(east(south(title, code).max_w(40), widget))
});

impl Interpret<Tui, Option<XYWH<u16>>> for State {
    fn interpret_word (&self, to: &mut Tui, sym: &impl Language) -> Perhaps<XYWH<u16>> {
        match sym.src()? {
            Some(":foo") => "foo".draw(to),
            Some(":bar") => "bar".draw(to),
            Some(":foobar") => "FOOBAR".draw(to),
            _ => todo!()
        }
    }
    fn interpret_expr (&self, to: &mut Tui, src: &impl Expression) -> Perhaps<XYWH<u16>> {
        Ok(Some(if let Some(area) = eval_view(self, to, src)? {
            area
        } else if let Some(area) = Tui::eval_view(self, to, src)? {
            area
        } else {
            return Err(format!("App::interpret_expr: unexpected: {src:?}").into())
        }))
    }
}

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

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

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

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

const VIEWS: &'static [&'static str] = &[
    stringify! { :foobar },
    stringify! { (text FOOBAR) },
    stringify! { (bg (g 8) :foobar) },
    stringify! { (fill/xy :foobar) },
    stringify! { (bsp/s (text foo) (text bar)) },
    stringify! { (bsp/s :foo :bar) },
    stringify! { (bsp/s (bg (g 16) :foo) (bg (g 32) :bar)) },
    stringify! { (bsp/s (max/xy 20 10 (bg (g 16) :foo)) (max/y 5 (bg (g 32) :bar))) },
    stringify! { (bsp/e (bg (g 16) :foo) (bg (g 32) :bar)) },
    stringify! { (fixed/xy 20 10 :foobar) },
    stringify! { (bsp/s (fixed/xy 5 6 :foo) (fixed/xy 7 8 :bar)) },
    stringify! { (bsp/e (fixed/xy 5 6 :foo) (fixed/xy 7 8 :bar)) },
    stringify! { (bsp/n (fixed/xy 5 6 :foo) (fixed/xy 7 8 :bar)) },
    stringify! { (bsp/w (fixed/xy 5 6 :foo) (fixed/xy 7 8 :bar)) },
    stringify! { (bsp/a (fixed/xy 5 6 :foo) (fixed/xy 7 8 :bar)) },
    stringify! { (bsp/b (fixed/xy 5 6 :foo) (fixed/xy 7 8 :bar)) },
    stringify! {
        (bsp/s
          (bsp/e       (align/nw (fixed/xy 5 3 :foo))
            (bsp/e     (align/n  (fixed/xy 5 3 :foo))
                       (align/ne (fixed/xy 5 3 :foo))))
            (bsp/s
              (bsp/e   (align/w  (fixed/xy 5 3 :foo))
                (bsp/e (align/c  (fixed/xy 5 3 :foo))
                       (align/e  (fixed/xy 5 3 :foo))))
              (bsp/e   (align/sw (fixed/xy 5 3 :foo))
                (bsp/e (align/s  (fixed/xy 5 3 :foo))
                       (align/se (fixed/xy 5 3 :foo))))))
    },
    stringify! {
        (bsp/s
          (bsp/e     (fixed/xy 8 5 (align/nw :foo))
            (bsp/e   (fixed/xy 8 5 (align/n  :foo))
                     (fixed/xy 8 5 (align/ne :foo))))
          (bsp/s
            (bsp/e   (fixed/xy 8 5 (align/w  :foo))
              (bsp/e (fixed/xy 8 5 (align/c  :foo))
                     (fixed/xy 8 5 (align/e  :foo))))
            (bsp/e   (fixed/xy 8 5 (align/sw :foo))
              (bsp/e (fixed/xy 8 5 (align/s  :foo))
                     (fixed/xy 8 5 (align/se :foo))))))
    },
    stringify! {
        (bsp/s
          (bsp/e     (grow/xy 1 1 (fixed/xy 8 5 (align/nw :foo)))
            (bsp/e   (grow/xy 1 1 (fixed/xy 8 5 (align/n  :foo)))
                     (grow/xy 1 1 (fixed/xy 8 5 (align/ne :foo)))))
          (bsp/s
            (bsp/e   (grow/xy 1 1 (fixed/xy 8 5 (align/w  :foo)))
              (bsp/e (grow/xy 1 1 (fixed/xy 8 5 (align/c  :foo)))
                     (grow/xy 1 1 (fixed/xy 8 5 (align/e  :foo)))))
            (bsp/e   (grow/xy 1 1 (fixed/xy 8 5 (align/sw :foo)))
              (bsp/e (grow/xy 1 1 (fixed/xy 8 5 (align/s  :foo)))
                     (grow/xy 1 1 (fixed/xy 8 5 (align/se :foo)))))))
    },
    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) {}