use crate::{*, Color::*};
use ratatui::{prelude::{Position}};

pub const ICON_DEC_V: &[char] = &['▲'];
pub const ICON_INC_V: &[char] = &['▼'];
pub const ICON_DEC_H: &[char] = &[' ', '🞀', ' '];
pub const ICON_INC_H: &[char] = &[' ', '🞂', ' '];

pub fn x_scroll () -> impl Draw<Tui> {
    draw(|to: &mut Tui|{
        let XYWH(x1, y1, w, _h) = to.area();
        let x2 = x1 + w;
        for (i, x) in (x1..=x2).enumerate() {
            if let Tui::Draw(buf, ..) = to {
                if let Some(cell) = buf.cell_mut(Position::from((x, y1))) {
                    if i < (ICON_DEC_H.len()) {
                        cell.set_fg(Rgb(255, 255, 255));
                        cell.set_bg(Rgb(0, 0, 0));
                        cell.set_char(ICON_DEC_H[i as usize]);
                    } else if i > (w as usize - ICON_INC_H.len()) {
                        cell.set_fg(Rgb(255, 255, 255));
                        cell.set_bg(Rgb(0, 0, 0));
                        cell.set_char(ICON_INC_H[w as usize - i]);
                    } else if false {
                        cell.set_fg(Rgb(255, 255, 255));
                        cell.set_bg(Reset);
                        cell.set_char('━');
                    } else {
                        cell.set_fg(Rgb(0, 0, 0));
                        cell.set_bg(Reset);
                        cell.set_char('╌');
                    }
                }
            }
        }
        Ok(Some(XYWH(x1, y1, w, 1)))
    })
}

pub fn y_scroll () -> impl Draw<Tui> {
    draw(|to: &mut Tui|{
        let XYWH(x1, y1, _w, h) = to.area();
        let y2 = y1 + h;
        for (i, y) in (y1..=y2).enumerate() {
            if let Tui::Draw(buf, ..) = to {
                if let Some(cell) = buf.cell_mut(Position::from((x1, y))) {
                    if (i as usize) < (ICON_DEC_V.len()) {
                        cell.set_fg(Rgb(255, 255, 255));
                        cell.set_bg(Rgb(0, 0, 0));
                        cell.set_char(ICON_DEC_V[i as usize]);
                    } else if (i as usize) > (h as usize - ICON_INC_V.len()) {
                        cell.set_fg(Rgb(255, 255, 255));
                        cell.set_bg(Rgb(0, 0, 0));
                        cell.set_char(ICON_INC_V[h as usize - i]);
                    } else if false {
                        cell.set_fg(Rgb(255, 255, 255));
                        cell.set_bg(Reset);
                        cell.set_char('‖'); // ━
                    } else {
                        cell.set_fg(Rgb(0, 0, 0));
                        cell.set_bg(Reset);
                        cell.set_char('╎'); // ━
                    }
                }
            }
        }
        Ok(Some(XYWH(x1, y1, 1, h)))
    })
}