use std::rc::Rc;

use wasm_bindgen::JsCast;
use web_sys::{Element, PointerEvent};
use yew::{function_component, html, use_state_eq, Callback, Html, Properties, UseStateHandle};
#[derive(Clone, Eq, PartialEq)]
pub enum PanelDirection {
    Horizontal,
    Vertical,
}

#[derive(PartialEq, Properties)]
pub struct SplitPanelProps {
    pub direction: PanelDirection,
    pub first: Html,
    pub second: Html,
}

#[function_component(SplitPanel)]
pub fn split_panel(props: &SplitPanelProps) -> Html {
    let is_dragging: Rc<UseStateHandle<Option<f64>>> = use_state_eq(|| None).into();
    let dragged_space: Rc<UseStateHandle<Option<f64>>> = use_state_eq(|| None).into();
    let wrapper_class = match props.direction {
        PanelDirection::Horizontal => "hpanelwrapper",
        PanelDirection::Vertical => "vpanelwrapper",
    };
    let wrapper_class = if (**is_dragging).is_some() {
        format!("{} dragging", wrapper_class)
    } else {
        wrapper_class.to_owned()
    };
    let panel_class = match props.direction {
        PanelDirection::Horizontal => "hpanel",
        PanelDirection::Vertical => "vpanel",
    };
    let divider_class = match props.direction {
        PanelDirection::Horizontal => "hdivider",
        PanelDirection::Vertical => "vdivider",
    };
    let row_or_col = match props.direction {
        PanelDirection::Horizontal => "columns",
        PanelDirection::Vertical => "rows",
    };

    let layout = match **dragged_space {
        None => format!("grid-template-{}: 1fr 4px 1fr", row_or_col),
        Some(custom) => format!("grid-template-{}: {}px 4px 1fr", row_or_col, custom),
    };
    let is_dragging_forup = is_dragging.clone();
    let dragged_space_formove = dragged_space.clone();
    let dir = props.direction.clone();
    match **is_dragging {
        None => {
            html! {
              <div class={wrapper_class} style={layout}>
                <div class={panel_class}>{props.first.clone()}</div>
                <div class={divider_class}
                  onpointerdown={Callback::from(move |e: PointerEvent| {
                    match e.target() {
                        None => {},
                        Some(t) => {
                            let el: Element = JsCast::unchecked_into::<Element>(
                                JsCast::unchecked_into::<Element>(t)
                                    .parent_node().expect("Parent exists"));
                            let top =
                                match dir {
                                    PanelDirection::Horizontal => el.get_bounding_client_rect().x(),
                                    PanelDirection::Vertical => el.get_bounding_client_rect().y()
                                };
                            is_dragging.set(Some(top));
                        }
                    }
                  })}
                />
                <div class={panel_class}>{props.second.clone()}</div>
              </div>
            }
        }
        Some(start) => {
            html! {
                <div class={wrapper_class} style={layout}
                       onpointerup={Callback::from(move |_| {
                           is_dragging_forup.set(None);
                       })}
                       onpointermove={Callback::from(move |e: PointerEvent| {
                           let distance = match dir {
                               PanelDirection::Horizontal => e.client_x() as f64,
                               PanelDirection::Vertical => e.client_y() as f64
                           } - start - 2.0;
                         (*dragged_space_formove).set(Some(distance));
                       })}
                >
                    <div class={panel_class}>{props.first.clone()}</div>
                    <div class={divider_class}
                     />
                    <div class={panel_class}>{props.second.clone()}</div>
                </div>
            }
        }
    }
}