public class FunctionManager {
    private int aLinear, bLinear, aSquare, bSquare, cSquare;

    private static final int X_START = -10;
    private static final int X_STOP = 10;
    private static final int X_STEP = 1;

    private static final int Y_START = -10;
    private static final int Y_STOP = 10;
    private static final int Y_STEP = 1;

    public FunctionManager(int aLinear, int bLinear, int aSquare, int bSquare, int cSquare) {
        this.aLinear = aLinear;
        this.bLinear = bLinear;
        this.aSquare = aSquare;
        this.bSquare = bSquare;
        this.cSquare = cSquare;
        printGraph();
    }

    private void printGraph() {
        for (int y = Y_START;y<= Y_STOP;y+=Y_STEP) {
            // Blok pro průchod s konkrétní hodnotou y
            buildRow(y);
            System.out.println();
        }
        printXAxis();
    }

    private void printXAxis() {
        System.out.print("     ");
        for (int x=X_START; x<= X_STOP; x+= X_STEP){
            System.out.print(String.format("%-5s",x));
        }
    }

    private void buildRow(int y) {
        printYAxis(y);
        for(int x = X_START; x<= X_STOP;x+=X_STEP){
            // Blok pro průchod s konkrétní hodnotou x a y
            buildPoint(x,y);
        }
    }

    private void buildPoint(int x, int y) {
        boolean isLinear = testIfLinearFunctionIsHit(x,y);
        boolean isSquare = testIfSquareFunctionIsHit(x,y);

        if(isLinear && isSquare) {
            System.out.print("  ~  ");
        } else if (isLinear && (!isSquare)) {
            System.out.print("  -  ");
        } else if((!isLinear) && isSquare){
            System.out.print("  *  ");
        } else {
            System.out.print("     ");
        }
    }

    private boolean testIfSquareFunctionIsHit(int x, int y) {
        return g(x) == y;
    }

    private boolean testIfLinearFunctionIsHit(int x, int y) {
        return f(x) == y;
    }

    private int f(int x) {
        // return linear function
        return aLinear * x + bLinear;
    }

    private int g(int x){
        return aSquare * x * x + bSquare * x + cSquare;
    }

    private void printYAxis(int y) {
        System.out.print(String.format("%-5s",y));
    }

}