class Game{
    constructor(eventBus, grid, previewGrid, pieceFactory){
        this.eventBus = eventBus;
        this.lastTime = performance.now();
        this.dropCounter = 0;
        this.dropInterval = 300;
        this.grid = grid;
        this.previewGrid = previewGrid;
        this.pieceFactory = pieceFactory;
        this.bagGenerator = this.pieceFactory.bagGenerator();
        this.loopRequestID = null;
        this.currentPiece = null;
        this.nextPiece = null;
        this.level = 1;
        this.lines = 0;
        this.score = 0;
        this.moveHandler = this.moveHandler.bind(this);
        this.lockPiece = this.lockPiece.bind(this);
        this._setupInputListeners();
        this.loop = this.loop.bind(this);
        this.eventBus.emit("update",  this.uiState());
        this.subscriptions = []; // Подписки.
        // Смотреть здесь
        this.unsubscribleStartGameplay = this.eventBus.on("start-gameplay", ({})=>{
            this._setupInputListeners();
        });
        this.unsubscribleStopGameplay = this.eventBus.on("stop-gameplay", ({})=>{
            this.unSetupInputListeners();
        })
    }
    getRenderState(){
        return {
            matrix:this.grid.matrix,
            piece:this.currentPiece,
            nextMatrix:this.previewGrid.matrix,
            nextPiece:this.nextPiece,
        };
    }
    moveHandler({dx, dy}){ //Деструктуризация moveState
      this.move(dx, dy);
    }
    _setupInputListeners() {
        this.move_off = this.eventBus.on("move", this.moveHandler);
        this.rotate_off = this.eventBus.on("rotate", ()=>{
            this.rotate();
        });
        this.lockPiece_off = this.eventBus.on("lockPiece", this.lockPiece);
    }
    unSetupInputListeners() {
        // Вызываем сохраненные функции-отписки, которые мы получили от eventBus.on()
        if(this.move_off) this.move_off();
        if(this.rotate_off) this.rotate_off();
        if(this.lockPiece_off) this.lockPiece_off();
    }
    loop(time){
        const deltaTime = time - this.lastTime;
        this.lastTime = time;
        this.dropCounter += deltaTime;
        if (this.dropCounter > this.dropInterval) {
            this.eventBus.emit("move", {dx:0, dy:1});
            this.dropCounter -= this.dropInterval;
        }
        this.eventBus.emit("render", this.getRenderState());
        this.loopRequestID = window.requestAnimationFrame(this.loop);
    }
    spawnNewPiece() {
        if(this.nextPiece == null) {
            const currentType = this.bagGenerator.next().value;
            const nextType = this.bagGenerator.next().value;
            this.currentPiece = this.pieceFactory.generatePieceByType(currentType, this.grid.width, this.grid.height);
            this.nextPiece = this.pieceFactory.generatePieceByType(nextType, this.previewGrid.width, this.previewGrid.height, true);
        }
        else{
            const nextType = this.bagGenerator.next().value;
            this.currentPiece = this.pieceFactory.generatePieceByType(this.nextPiece.type, this.grid.width, this.grid.height);
            this.nextPiece = this.pieceFactory.generatePieceByType(nextType, this.previewGrid.width, this.previewGrid.height, true);
        }
   }
   move(dx, dy){
        if(this.currentPiece === null) return;
        const moved = this.currentPiece.move(dx, dy);
        if(!this.grid.isCollision(moved)){
            this.currentPiece = moved;
            /*if (dy === 1) {
                this.dropCounter = 0;
            }*/
        }else if(dy == 1){
            //this.eventBus.emit("render", this.getRenderState());
            this.eventBus.emit("lockPiece",{piece:this.currentPiece});
        }
   }
   rotate(){
        if(this.currentPiece === null) return;
        const rotated = this.currentPiece.rotate();
        if(!this.grid.isCollision(rotated)){
            this.currentPiece = rotated;
        }
   }
   async lockPiece({piece}){
        this.grid.matrix = this.grid.getMergedMatrix(piece);
        const blinkedIndexes = this.grid.getBlinkedIndexes();
        if(blinkedIndexes.length > 0){
            this.eventBus.emit("force-render", this.getRenderState()); //
            await this.eventBus.emitAsync("animate",{count:4, time:100, indexes:blinkedIndexes, matrix:this.grid.matrix});
            this.lines += this.grid.deleteLines();
            this.eventBus.emit("update", this.uiState());
        }
        this.spawnNewPiece();
        if(this.grid.isCollision(this.currentPiece)){
            this.eventBus.emit("gameEnd",{});
        }
   }
   uiState(){
       return {
           level:this.level,
           lines:this.lines,
           score:this.score
       }
   }
    start(){
        if(this.loopRequestID) return;
        this.spawnNewPiece();
        this.lastTime = performance.now();
        this.loopRequestID = window.requestAnimationFrame(this.loop)
    }
}