import CoreFeature from '../CoreFeature.js';
import Row from '../row/Row.js';

export default class InteractionManager extends CoreFeature {
	
	constructor (table){
		super(table);
		
		this.el = null;
		
		this.abortClasses = ["tabulator-headers", "tabulator-table"];
		
		this.previousTargets = {};
		
		this.listeners = [
			"click",
			"dblclick",
			"contextmenu",
			"mouseenter",
			"mouseleave",
			"mouseover",
			"mouseout",
			"mousemove",
			"touchstart",
			"touchend",
		];
		
		this.componentMap = {
			"tabulator-cell":"cell",
			"tabulator-row":"row",
			"tabulator-group":"group",
			"tabulator-col":"column",
		};
		
		this.pseudoTrackers = {
			"row":{
				subscriber:null,
				target:null,
			},
			"cell":{
				subscriber:null,
				target:null,
			},
			"group":{
				subscriber:null,
				target:null,
			},
			"column":{
				subscriber:null,
				target:null,
			},
		};
		
		this.pseudoTracking = false;
	}
	
	initialize(){
		this.el = this.table.element;
		
		this.buildListenerMap();
		this.bindSubscriptionWatchers();
	}
	
	buildListenerMap(){
		var listenerMap = {};
		
		this.listeners.forEach((listener) => {
			listenerMap[listener] = {
				handler:null,
				components:[],
			};
		});
		
		this.listeners = listenerMap;
	}
	
	bindPseudoEvents(){
		Object.keys(this.pseudoTrackers).forEach((key) => {
			this.pseudoTrackers[key].subscriber = this.pseudoMouseEnter.bind(this, key);
			this.subscribe(key + "-mouseover", this.pseudoTrackers[key].subscriber);
		});
		
		this.pseudoTracking = true;
	}
	
	pseudoMouseEnter(key, e, target){
		if(this.pseudoTrackers[key].target !== target){
			
			if(this.pseudoTrackers[key].target){
				this.dispatch(key + "-mouseleave", e, this.pseudoTrackers[key].target);
			}
			
			this.pseudoMouseLeave(key, e);
			
			this.pseudoTrackers[key].target = target;
			
			this.dispatch(key + "-mouseenter", e, target);
		}
	}
	
	pseudoMouseLeave(key, e){
		var leaveList = Object.keys(this.pseudoTrackers),
		linkedKeys = {
			"row":["cell"],
			"cell":["row"],
		};
		
		leaveList = leaveList.filter((item) => {
			var links = linkedKeys[key];
			return item !== key && (!links || (links && !links.includes(item)));
		});
		
		
		leaveList.forEach((key) => {
			var target = this.pseudoTrackers[key].target;
			
			if(this.pseudoTrackers[key].target){
				this.dispatch(key + "-mouseleave", e, target);
				
				this.pseudoTrackers[key].target = null;
			}
		});
	}
	
	
	bindSubscriptionWatchers(){
		var listeners = Object.keys(this.listeners),
		components = Object.values(this.componentMap);
		
		for(let comp of components){
			for(let listener of listeners){
				let key = comp + "-" + listener;
				
				this.subscriptionChange(key, this.subscriptionChanged.bind(this, comp, listener));
			}
		}
		
		this.subscribe("table-destroy", this.clearWatchers.bind(this));
	}
	
	subscriptionChanged(component, key, added){
		var listener = this.listeners[key].components,
		index = listener.indexOf(component),
		changed = false;
		
		if(added){
			if(index === -1){
				listener.push(component);
				changed = true;
			}
		}else{
			if(!this.subscribed(component + "-" + key)){
				if(index > -1){
					listener.splice(index, 1);
					changed = true;
				}
			}
		}
		
		if((key === "mouseenter" || key === "mouseleave") && !this.pseudoTracking){
			this.bindPseudoEvents();
		}
		
		if(changed){
			this.updateEventListeners();
		}
	}
	
	updateEventListeners(){
		for(let key in this.listeners){
			let listener = this.listeners[key];
			
			if(listener.components.length){
				if(!listener.handler){
					listener.handler = this.track.bind(this, key);
					this.el.addEventListener(key, listener.handler);
					// this.el.addEventListener(key, listener.handler, {passive: true})
				}
			}else{
				if(listener.handler){
					this.el.removeEventListener(key, listener.handler);
					listener.handler = null;
				}
			}
		}
	}
	
	track(type, e){
		var path = (e.composedPath && e.composedPath()) || e.path;
		
		var targets = this.findTargets(path);
		targets = this.bindComponents(type, targets);
		
		this.triggerEvents(type, e, targets);
		
		if(this.pseudoTracking && (type == "mouseover" || type == "mouseleave") && !Object.keys(targets).length){
			this.pseudoMouseLeave("none", e);
		}
	}
	
	findTargets(path){
		var targets = {};
		
		let componentMap = Object.keys(this.componentMap);
		
		for (let el of path) {
			let classList = el.classList ? [...el.classList] : [];
			
			let abort = classList.filter((item) => {
				return this.abortClasses.includes(item);
			});
			
			if(abort.length){
				break;
			}
			
			let elTargets = classList.filter((item) => {
				return componentMap.includes(item);
			});
			
			for (let target of elTargets) {
				if(!targets[this.componentMap[target]]){
					targets[this.componentMap[target]] = el;
				}
			}
		}
		
		if(targets.group && targets.group === targets.row){
			delete targets.row;
		}
		
		return targets;
	}
	
	bindComponents(type, targets){
		//ensure row component is looked up before cell
		var keys = Object.keys(targets).reverse(),
		listener = this.listeners[type],
		targetMatches = {};
		
		for(let key of keys){
			let component;
			let target = targets[key];
			let previousTarget = this.previousTargets[key];
			
			if(previousTarget && previousTarget.target === target){
				component = previousTarget.component;
			}else{
				switch(key){
					case "row":
					case "group":
						if(listener.components.includes("row") || listener.components.includes("cell") || listener.components.includes("group")){
							let rows = this.table.rowManager.getVisibleRows(true);
						
							component = rows.find((row) => {
								return row.getElement() === target;
							});
						
							if(targets["row"] && targets["row"].parentNode && targets["row"].parentNode.closest(".tabulator-row")){
								targets[key] = false;
							}
						}
						break;
					
					case "column":
						if(listener.components.includes("column")){
							component = this.table.columnManager.findColumn(target);
						}
						break;
					
					case "cell":
						if(listener.components.includes("cell")){
							if(targets["row"] instanceof Row){
								component = targets["row"].findCell(target);
							}else{	
								if(targets["row"]){
									console.warn("Event Target Lookup Error - The row this cell is attached to cannot be found, has the table been reinitialized without being destroyed first?");
								}
							}
						}
						break;
				}
			}
			
			if(component){
				targets[key] = component;
				targetMatches[key] = {
					target:target,
					component:component,
				};
			}
		}
		
		this.previousTargets = targetMatches;
		
		return targets;
	}
	
	triggerEvents(type, e, targets){
		var listener = this.listeners[type];
		
		for(let key in targets){
			if(targets[key] && listener.components.includes(key)){
				this.dispatch(key + "-" + type, e, targets[key]);
			}
		}
	}
	
	clearWatchers(){
		for(let key in this.listeners){
			let listener = this.listeners[key];
			
			if(listener.handler){
				this.el.removeEventListener(key, listener.handler);
				listener.handler = null;
			}
		}
	}
}