package dk.thoerup.calculator;

import android.app.Activity;
import android.os.Bundle;
import android.text.Editable;
import android.view.View;
import android.widget.EditText;

public class CalculatorActivity extends Activity {
    /** Called when the activity is first created. */
	
	EditText mEdit;
	
	
	double mVal1;
	char mOperation = ' ';
	boolean mClear = false;
		
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        
        findViewById(R.id.btn0).setOnClickListener( new NumericClick('0') );
        findViewById(R.id.btn1).setOnClickListener( new NumericClick('1') );
        findViewById(R.id.btn2).setOnClickListener( new NumericClick('2') );
        findViewById(R.id.btn3).setOnClickListener( new NumericClick('3') );
        findViewById(R.id.btn4).setOnClickListener( new NumericClick('4') );
        findViewById(R.id.btn5).setOnClickListener( new NumericClick('5') );
        findViewById(R.id.btn6).setOnClickListener( new NumericClick('6') );
        findViewById(R.id.btn7).setOnClickListener( new NumericClick('7') );
        findViewById(R.id.btn8).setOnClickListener( new NumericClick('8') );
        findViewById(R.id.btn9).setOnClickListener( new NumericClick('9') );
     
        findViewById(R.id.btnback).setOnClickListener( new BackClick() );
        findViewById(R.id.btnpoint).setOnClickListener( new PointClick() );
        
        findViewById(R.id.btnadd).setOnClickListener( new OperationClick('+') );
        findViewById(R.id.btnsub).setOnClickListener( new OperationClick('-') );
        findViewById(R.id.btnmul).setOnClickListener( new OperationClick('*') );
        findViewById(R.id.btndiv).setOnClickListener( new OperationClick('/') );
        
        findViewById(R.id.btnsum).setOnClickListener( new SumClick() );
        
        mEdit = (EditText) findViewById(R.id.edit);
        mEdit.setCursorVisible(false);
       
        
    }
    
    
    class NumericClick implements View.OnClickListener {
    	char mNumval;

    	public NumericClick(char numval) {
    		mNumval = numval;
    	}
    	
		@Override
		public void onClick(View v) {
			Editable tempText = mEdit.getText();
			
			if (tempText.toString().equals("0") || mClear==true ) {
				tempText.clear();
			}
			tempText.append(mNumval);			
		}
    	
    }
    
    class BackClick implements View.OnClickListener {

		@Override
		public void onClick(View v) {
			if (mClear) {
				mEdit.setText("0");
				return;
			}
			
			Editable tempText = mEdit.getText();
			if (tempText.length() > 0) {
				CharSequence cs = tempText.subSequence(0, tempText.length() -1);
				mEdit.setText(cs);
			}
		}
    }
    
    class PointClick implements View.OnClickListener {

		@Override
		public void onClick(View v) {			
			
			Editable tempText = mEdit.getText();
			if (tempText.toString().indexOf('.') == -1) {
				tempText.append('.');
			}
		}
    }
    
    class OperationClick implements View.OnClickListener {
    	char mOp;
    	public OperationClick(char op) {
    		mOp = op;
    	}

		@Override
		public void onClick(View v) {			
			mVal1 = Double.parseDouble( mEdit.getText().toString() );
			mEdit.setText("0");
			
			mOperation = mOp;
			
		}
    }
    
    class SumClick implements View.OnClickListener {
		@Override
		public void onClick(View v) {
			if (mOperation == ' ') {
				return;
			}			
			
			double val2 = Double.parseDouble( mEdit.getText().toString() );

			Double res = 0.0;
			switch (mOperation) {
			case '+':
				res = mVal1 + val2;
				break;
			case '-':
				res = mVal1 - val2;
				break;
			case '*':
				res = mVal1 * val2;
				break;
			case '/':
				res = mVal1 / val2;
				break;				
			}
			
			if ( res.isInfinite() || res.isNaN() ) {
				mClear = true;
			}
			
			mEdit.setText( res.toString() );
			mOperation = ' ';
			mVal1 = res;
		}
    }    
}