class AgentController {
  constructor(canvas) {
    // Inicjalizacja
    this.ctx = canvas.getContext('2d');
    this.setCanvasSize(canvas);

    this.ownedProduct = Product.REGISTRY.empty;
    this.ownedProductAmount = 0;

    // Akcje
    this.actions = {
      'STATIONARY': 0,
      'IN_MOVE': 1,
      'IN_ROTATION': 2,
    }
    this.currentAction = this.actions.STATIONARY;

    // Pozycja i poruszanie się
    this.position = { x: 6, y: 0 };
    this.rotation = { z: 0 };
    this.speed = 90 - AgentMoveSpeed;
    this.rotationSpeed = 90 / ( 90 - AgentRotationSpeed);
    this.update();
  }

  setCanvasSize (canvas) {
    canvas.width = 2000;
    canvas.height = 900;
  }

  update() {
    this.clearCanvas();
    if (this.currentPath) {
      this.drawPath(this.currentPath);
    }
    this.drawAgent();

    requestAnimationFrame(this.update.bind(this));
  }

  updateAgentPosition() {
    return new Promise((resolve, reject) => {
      const cycle = async () => {
        if (!this.currentPathIndex) {
          this.currentPathIndex = 0;
        }
  
        let nearestPoint = this.currentPath[this.currentPathIndex];
  
        if (nearestPoint) {
          if (nearestPoint.action == PATHFINDING_ACTION.MOVE) {
            await this.moveInLine(nearestPoint.state.position);
          }
          if (nearestPoint.action == PATHFINDING_ACTION.ROTATE) {
            await this.rotate({ z: nearestPoint.state.rotation });
          }
  
          nearestPoint = this.currentPath[++this.currentPathIndex];
          if (!nearestPoint) {
            this.currentPath = [];
            this.currentPathIndex = 0;
            this.currentAction = this.actions.STATIONARY;
            resolve();
          } else {
            cycle();
          }
        } else {
          resolve();
        }
      }

      cycle();
    })
  }

  /**
   * 
   * @param {{ x: number, y: number }} position 
   */
  moveInLine(position) {
    return new Promise((resolve, reject) => {
      const cycle = () => {
        const { speed } = this;
        this.currentAction = this.actions.IN_MOVE;
        this.position = {
          x: this.position.x + (Math.sign(position.x - this.position.x)/speed),
          y: this.position.y + (Math.sign(position.y - this.position.y)/speed)
        }

        if (Math.abs(position.x - this.position.x) < 0.001 && Math.abs(position.y - this.position.y) < 0.001) {
          this.position = {
            x: Math.round(this.position.x),
            y: Math.round(this.position.y)
          }
          resolve();
        } else {
          requestAnimationFrame(() => cycle());
        }
      }

      cycle();
    });
  }

  /**
   * 
   * @param {{ x: number, y: number }} position 
   */
  findRequiredRotation(position) {
    if (position.x == this.position.x && position.y == this.position.y) {
      return this.rotation.z;
    }

    const compare = (a, b) => {
      return Math.abs(a - b) < 1;
    }

    if (compare(this.position.x, position.x)) {
      if (this.position.y < position.y) {
        return 180;
      } else {
        return 0;
      }
    } else {
      if (this.position.x < position.x) {
        return 90;
      } else {
        return 270;
      }
    }
  }

  /**
   * 
   * @param {{ z: number}} rotation
   * @returns 
   */
  rotate(rotation) {
    return new Promise((resolve, reject) => {
      if (this.rotation.z == rotation.z) {
        resolve();
      }

      const sign = (() => {
        if (((this.rotation.z > rotation.z) || (this.rotation.z == 0 && rotation.z == 270)) && !(this.rotation.z == 270 && rotation.z == 0)) {
          return -1;
        }
        return 1;
      })();

      const cycle = () => {
        this.currentAction = this.actions.IN_ROTATION;

        const oldZRotation = this.rotation.z;
        const newZRotation = rotation.z;

        const clampRotation = (rot) => (rot + 360) % 360;

        this.rotation = { z: clampRotation(oldZRotation + (this.rotationSpeed * sign)) };

        if (Math.abs(oldZRotation - newZRotation) < 5) {
          resolve();
          this.rotation = { z: clampRotation(newZRotation) }
        } else {
          requestAnimationFrame(() => cycle());
        } 
      }

      cycle();
    });
  }

  moveTo(x, y) {
    this.currentPath = this.findPathTo(x, y, this.position.x, this.position.y);
    return this.updateAgentPosition();
  }

  drawPath(path) {
    for(let i = 0; i < path.length - 1; i++) {
      this.ctx.beginPath();
        this.ctx.strokeWidth = 5;
        this.ctx.strokeStyle = 'red';
        this.ctx.moveTo(path[i].state.position.x * 100 + 50, path[i].state.position.y * 100 + 50);
        this.ctx.lineTo(path[i + 1].state.position.x * 100 + 50, path[i + 1].state.position.y * 100 + 50);
      this.ctx.stroke();
    }
  }

  drawAgent() {
    const {x, y} = this.position;
    const offset = 5;
    const rotation = this.rotation.z; 

    const newX = (x * 100) + (offset);
    const newY = (y * 100) + (offset);
    const w = 100 - (offset * 2);
    const h = 100 - (offset * 2);

    this.ctx.translate(newX + (w / 2), newY + (h / 2));
    this.ctx.rotate(rotation * Math.PI / 180);

    // Base shape
    this.ctx.clearRect(-(w / 2), -(h / 2), w, h);
    this.roundRect(-(w / 2), -(h / 2), w, h);

    // Eyes
    // this.roundRect(10 - (w / 2), 10 - (h / 2), w / 4, h / 4);
    // this.roundRect(80 - (3 * w / 4), 10 - (h / 2), w / 4, h / 4);
    this.ctx.fillStyle = 'red';
    this.ctx.fillRect(-(w/2) + 20, (-h/2) - 10, w - 40, 10);

    this.ctx.rotate(-rotation * Math.PI / 180);

    // Product
    this.ctx.font = '900 40px "Font Awesome 5 Free"';
    this.ctx.textAlign = 'center';
    this.ctx.fillStyle = 'white'; 
    this.ctx.fillText(this.ownedProduct.icon, 0, 15);

    // Amount
    if (this.ownedProductAmount) {
      this.ctx.font = '20px Montserrat';
      this.ctx.textAlign = 'left';
      this.ctx.fillStyle = 'white';
      this.ctx.fillText(this.ownedProductAmount, 10, 35);
    }

    this.ctx.translate(-(newX + (w / 2)), -(newY + (h / 2)));
  }

  findPathTo(dx, dy, sx, sy) {
    if (Grid.instance.getGrid()[dx][dy] == GRID_FIELD_TYPE.SHELF || Grid.instance.getGrid()[dx][dy] == GRID_FIELD_TYPE.STORAGE) {
      if (Grid.instance.getGrid()[dx][dy - 1] == GRID_FIELD_TYPE.PATH) {
        return Pathfinding.search({ position: { x: sx, y: sy }, rotation: this.rotation.z }, { position: { x: dx, y: dy - 1 }, rotation: 180 });
      }
      return Pathfinding.search({ position: { x: sx, y: sy }, rotation: this.rotation.z }, { position: { x: dx, y: dy + 1 }, rotation: 0 });
    }
    return Pathfinding.search({ position: { x: sx, y: sy }, rotation: this.rotation.z }, { position: { x: dx, y: dy }, rotation: this.rotation.z });
  }

  clearCanvas() {
    this.ctx.clearRect(0, 0, 2000, 900);
  }

  roundRect(x, y, w, h, r = 20) {
    this.ctx.lineWidth = 5;
    this.ctx.strokeStyle = 'red';
    this.ctx.beginPath();
      this.ctx.moveTo(x + r, y);
      this.ctx.lineTo(x + w - r, y);
      this.ctx.quadraticCurveTo(x + w, y, x + w, y + r);
      this.ctx.lineTo(x + w, y + h - r);
      this.ctx.quadraticCurveTo(x + w, y + h, x + w - r, y + h);
      this.ctx.lineTo(x + r, y + h);
      this.ctx.quadraticCurveTo(x, y + h, x, y + h - r);
      this.ctx.lineTo(x, y + r);
      this.ctx.quadraticCurveTo(x, y, x + r, y);
    this.ctx.closePath();
    this.ctx.stroke();
  }
}