"use strict";

let accordion_view_list = [];
const accordion_resize_observer = new ResizeObserver((changed_item_list) => {
	for(let one_changed_item of changed_item_list){
		accordion_body_resize(one_changed_item.target);
	}
});



window.addEventListener("load", function(event){
	// COLLECT ACCORDION VIEWS //
	let accordion_root_list = document.getElementsByClassName("accordion");
	for(let one_accordion_root of accordion_root_list){
		// collect this view
		let accordion_view = accordion_collect_view(one_accordion_root);
		accordion_view_list.push(accordion_view);
		
		// initialized this view
		accordion_init(accordion_view);
	}
});



/**
* HELPER: Collect data for one accordion view.
* 
* @param root		Root element.
* 
* @return			Accordion view object.
*/
function accordion_collect_view(root){
	// COLLECT ITEMS //
	let item_list = [];
	for(let one_child of root.children){
		// maybe unwrap
		if(one_child.classList.contains("wrapper")) one_child = one_child.children[0] ?? null;
		
		// validate child as item
		if(!one_child.classList.contains("item")) continue;
		
		// find head element
		let head;
		for(let one_item_child of one_child.children){
			if(one_item_child.classList.contains("head")){
				head = one_item_child;
				break;
			}
		}
		if(head === undefined) throw "Unable to find accordion item head";
		
		// find icon
		let icon;
		for(let one_head_child of head.children){
			if(one_head_child.classList.contains("icon")){
				icon = one_head_child;
				break;
			}
		}
		if(icon === undefined) throw "Unable to find accordion item icon";
		
		// find title
		let title;
		for(let one_head_child of head.children){
			if(one_head_child.classList.contains("title")){
				title = one_head_child;
				break;
			}
		}
		if(title === undefined) throw "Unable to find accordion item title";
		
		// find body container
		let bodyContainer;
		for(let one_item_child of one_child.children){
			if(one_item_child.classList.contains("body-container")){
				bodyContainer = one_item_child;
				break;
			}
		}
		if(bodyContainer === undefined) throw "Unable to find accordion body container";
		
		// add to item list
		item_list.push({
			element: one_child,
			head: head,
			icon: icon,
			title: title,
			bodyContainer: bodyContainer,
		});
	}
	
	
	// BUILD OBJECT //
	return {
		root: root,
		item_list: item_list,
	};
}



/**
* HELPER: Initialize accordion view.
* 
* @param accordion		Accordion view object.
*/
function accordion_init(accordion){
	// REGISTER ONCLICK HANDLERS //
	for(let one_item of accordion.item_list){
		// head
		one_item.head.onclick = function(event){
			event.stopPropagation();
			accordion_click(one_item, accordion);
		};
		
		// title
		one_item.title.tabIndex = 0;
		one_item.title.onclick = function(event){
			event.stopPropagation();
			accordion_click(one_item, accordion);
		};
		one_item.title.onkeypress = function(event){
			if(event.key === "Enter"){
				event.preventDefault();
				event.stopPropagation();
				accordion_click(one_item, accordion);
			}
		};
	}
	
	
	// RESET OPENED STATE //
	for(let one_item of accordion.item_list){
		accordion_state_set(one_item, accordion_state_get(one_item));
	}
}



/**
* CALLBACK: Item head was clicked.
* 
* @param item			Accordion item.
* @param accordion		This item's accordion view object.
*/
function accordion_click(item, accordion){
	// get our old state
	let old_state = accordion_state_get(item);
	
	// close all other items //
	for(let one_item of accordion.item_list){
		accordion_state_set(one_item, false);
	}
	
	// set our new state
	accordion_state_set(item, !old_state);
}



/**
* GETTER: Get state of one accordion item.
* 
* @param item		Accordion item.
*/
function accordion_state_get(item){
	return item.element.classList.contains("open");
}



/**
* SETTER: Set state of one accordion item.
* 
* @param item		Accordion item.
* @param state		New state.
*/
function accordion_state_set(item, state){
	// set observe state
	if(state) accordion_resize_observer.observe(item.bodyContainer);
	else accordion_resize_observer.unobserve(item.bodyContainer);
	
	// update class
	item.element.classList.remove("open");
	if(state) item.element.classList.add("open");
	
	// update icon direction
	item.icon.classList.remove("ti-chevron-up", "ti-chevron-right", "ti-chevron-down", "ti-chevron-left");
	if(state) item.icon.classList.add("ti-chevron-down");
	else item.icon.classList.add("ti-chevron-right");
	
	// set body height
	if(state) accordion_body_resize(item.bodyContainer);
	else item.bodyContainer.style.maxHeight = 0;
}



/**
* HELPER: Resize body height.
* 
* @param bodyContainer		Accordion body container.
*/
function accordion_body_resize(bodyContainer){
	bodyContainer.style.maxHeight = bodyContainer.scrollHeight + "px";
}