use std::{ops::Range, str::FromStr};

use egui::{
    ecolor::HexColor, Align, Color32, Frame, Layout, Response, RichText, Sense, TextEdit, Ui,
    UiBuilder, Vec2, WidgetText,
};

pub trait UiExt {
    fn section(&mut self, title: impl Into<String>, add_contents: impl FnOnce(&mut Ui));
    fn selectable_button(&mut self, selected: bool, text: impl Into<WidgetText>) -> Response;
    fn selectable_option<T: Eq>(
        &mut self,
        current_value: &mut T,
        selected_value: T,
        text: impl Into<WidgetText>,
    ) -> Response {
        let response = self.selectable_button(*current_value == selected_value, text);
        if response.clicked() {
            *current_value = selected_value;
        }
        response
    }

    fn color_pair_button(&mut self, left: Color32, right: Color32) -> Response;

    fn color_picker(&mut self, color: &mut Color32, hex: &mut String) -> Response;

    fn number_picker<T: FromStr + PartialOrd>(
        &mut self,
        text: &mut String,
        value: &mut T,
        range: Range<T>,
    );
}

impl UiExt for Ui {
    fn section(&mut self, title: impl Into<String>, add_contents: impl FnOnce(&mut Ui)) {
        let mut frame = Frame::group(self.style());
        frame.outer_margin.top += 10.0;
        frame.inner_margin.top += 2.0;
        let res = frame.show(self, add_contents);
        let text = RichText::new(title).background_color(self.style().visuals.panel_fill);
        let old_rect = res.response.rect;
        let mut text_rect = old_rect;
        text_rect.min.x += 6.0;
        let new_rect = self
            .allocate_new_ui(UiBuilder::new().max_rect(text_rect), |ui| ui.label(text))
            .response
            .rect;
        self.allocate_space((old_rect.max - new_rect.max) - (old_rect.min - new_rect.min));
    }

    fn selectable_button(&mut self, selected: bool, text: impl Into<WidgetText>) -> Response {
        self.style_mut().visuals.widgets.inactive.bg_fill = Color32::TRANSPARENT;
        self.style_mut().visuals.widgets.hovered.bg_fill = Color32::TRANSPARENT;
        self.style_mut().visuals.widgets.active.bg_fill = Color32::TRANSPARENT;
        let mut selected = selected;
        self.checkbox(&mut selected, text)
    }

    fn color_pair_button(&mut self, left: Color32, right: Color32) -> Response {
        let button_size = Vec2::new(60.0, 20.0);
        let (rect, response) = self.allocate_at_least(button_size, Sense::click());
        let center_x = rect.center().x;
        let left_rect = rect.with_max_x(center_x);
        self.painter().rect_filled(left_rect, 0.0, left);
        let right_rect = rect.with_min_x(center_x);
        self.painter().rect_filled(right_rect, 0.0, right);

        let style = self.style().interact(&response);
        self.painter().rect_stroke(rect, 0.0, style.fg_stroke);
        response
    }

    fn color_picker(&mut self, color: &mut Color32, hex: &mut String) -> Response {
        self.allocate_ui_with_layout(
            Vec2::new(100.0, 130.0),
            Layout::top_down_justified(egui::Align::Center),
            |ui| {
                let (rect, _) = ui.allocate_at_least(Vec2::new(100.0, 100.0), Sense::hover());
                ui.painter().rect_filled(rect, 0.0, *color);
                let resp = ui.text_edit_singleline(hex);
                if resp.changed() {
                    if let Ok(new_color) = HexColor::from_str_without_hash(hex) {
                        *color = new_color.color();
                    }
                }
                resp
            },
        )
        .inner
    }

    fn number_picker<T: FromStr + PartialOrd>(
        &mut self,
        text: &mut String,
        value: &mut T,
        range: Range<T>,
    ) {
        let res = self.add(TextEdit::singleline(text).horizontal_align(Align::Max));
        if res.changed() {
            if let Some(new_value) = text.parse().ok().filter(|v| range.contains(v)) {
                *value = new_value;
            }
        }
    }
}