package de.pointedears.converter.app;

import java.util.HashMap;

import android.app.Activity;
import android.os.Bundle;
import android.text.Editable;
import android.view.KeyEvent;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.View.OnKeyListener;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemSelectedListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Spinner;
import android.widget.TextView;
import de.pointedears.converter.R;

/**
 * Activity that implements length conversion
 * 
 * @author pelinux
 */
public class TemperaturesActivity extends Activity
{
  /*
   * Constants for mapping value strings to internal IDs
   */
  private static final String VALUE_CELSIUS = "C"; //$NON-NLS-1$
  private static final String VALUE_FAHRENHEIT = "F"; //$NON-NLS-1$
  private static final String VALUE_KELVIN = "K"; //$NON-NLS-1$
  private static final int ITEM_CELSIUS = 0;
  private static final int ITEM_FAHRENHEIT = 1;
  private static final int ITEM_KELVIN = 2;

  /**
   * Maps value strings to internal IDs
   */
  private final static HashMap<String, Integer> valueToId =
    new HashMap<String, Integer>();

  /* Unit spinners (dropdowns) */
  private Spinner spinnerUnit1;
  private Spinner spinnerUnit2;

  /* Hint that value is off scale */
  private TextView textOffScale;

  static
  {
    TemperaturesActivity.valueToId.put(TemperaturesActivity.VALUE_CELSIUS,
      TemperaturesActivity.ITEM_CELSIUS);
    TemperaturesActivity.valueToId.put(TemperaturesActivity.VALUE_FAHRENHEIT,
      TemperaturesActivity.ITEM_FAHRENHEIT);
    TemperaturesActivity.valueToId.put(TemperaturesActivity.VALUE_KELVIN,
      TemperaturesActivity.ITEM_KELVIN);
  }

  /** Called when the activity is first created. */

  @Override
  public void onCreate(Bundle savedInstanceState)
  {
    super.onCreate(savedInstanceState);
    this.setContentView(R.layout.activity_temperatures);

    this.textOffScale =
      (TextView) this.findViewById(R.id.temperatures_text_off_scale);

    final EditText editValue1 =
      (EditText) this.findViewById(R.id.temperatures_edit_value1);
    final EditText editValue2 =
      (EditText) this.findViewById(R.id.temperatures_edit_value2);

    final OnKeyListener editValue1OnKey = new OnKeyListener() {
      @Override
      public boolean onKey(View v, int keyCode, KeyEvent event)
      {
        Editable editable1 = ((EditText) v).getText();

        Double value1;
        try
        {
          value1 = Double.parseDouble(editable1.toString());
        }
        catch (NumberFormatException e)
        {
          value1 = null;
        }

        String string2 = ""; //$NON-NLS-1$
        if (value1 != null)
        {
          string2 = TemperaturesActivity.this.getConvertedValue(value1, false);
        }

        editValue2.setText(string2);

        return false;
      }
    };
    editValue1.setOnKeyListener(editValue1OnKey);

    final OnKeyListener editValue2OnKey = new OnKeyListener() {
      @Override
      public boolean onKey(View v, int keyCode, KeyEvent event)
      {
        Editable editable2 = ((EditText) v).getText();

        Double value2;
        try
        {
          value2 = Double.parseDouble(editable2.toString());
        }
        catch (NumberFormatException e)
        {
          value2 = null;
        }

        String string1 = ""; //$NON-NLS-1$
        if (value2 != null)
        {
          string1 = TemperaturesActivity.this.getConvertedValue(value2, true);
        }

        editValue1.setText(string1);

        return false;
      }
    };
    editValue2.setOnKeyListener(editValue2OnKey);

    this.spinnerUnit1 =
      (Spinner) this.findViewById(R.id.temperatures_spinner_unit1);
    this.spinnerUnit2 =
      (Spinner) this.findViewById(R.id.temperatures_spinner_unit2);

    this.spinnerUnit1.setOnItemSelectedListener(new OnItemSelectedListener() {
      @Override
      public void onItemSelected(AdapterView<?> arg0, View arg1, int arg2,
        long arg3)
      {
        /* Simulate input in second EditText so that first EditText is updated */
        editValue2OnKey.onKey(editValue2, 0, null);
      }

      @Override
      public void onNothingSelected(AdapterView<?> arg0)
      {
        /* no-op */
      }
    });

    this.spinnerUnit2.setSelection(1);
    this.spinnerUnit2.setOnItemSelectedListener(new OnItemSelectedListener() {
      @Override
      public void onItemSelected(AdapterView<?> arg0, View arg1, int arg2,
        long arg3)
      {
        /* Simulate input in first EditText so that second EditText is updated */
        editValue1OnKey.onKey(editValue1, 0, null);
      }

      @Override
      public void onNothingSelected(AdapterView<?> arg0)
      {
        /* no-op */
      }
    });

    Button buttonClear =
      (Button) this.findViewById(R.id.temperatures_button_clear);
    buttonClear.setOnClickListener(new OnClickListener() {

      @SuppressWarnings("nls")
      @Override
      public void onClick(View v)
      {
        editValue1.setText("");
        editValue2.setText("");
      }
    });
  }

  /**
   * @param value
   * @return
   */
  private String getConvertedValue(double value, boolean reverse)
  {
    int selectedItemPosition1 = this.spinnerUnit1.getSelectedItemPosition();
    int selectedItemPosition2 = this.spinnerUnit2.getSelectedItemPosition();
    String[] itemArray =
      this.getResources().getStringArray(R.array.temperature_units_values);
    String selectedItemValue1 = itemArray[selectedItemPosition1];
    String selectedItemValue2 = itemArray[selectedItemPosition2];

    if (reverse)
    {
      String tmp = selectedItemValue1;
      selectedItemValue1 = selectedItemValue2;
      selectedItemValue2 = tmp;
    }

    int itemId1 = TemperaturesActivity.valueToId.get(selectedItemValue1);
    int itemId2 = TemperaturesActivity.valueToId.get(selectedItemValue2);

    Double newValue = value;

    this.textOffScale.setVisibility(View.INVISIBLE);

    switch (itemId1)
    {
      case ITEM_CELSIUS:
        switch (itemId2)
        {
          case ITEM_FAHRENHEIT:
            newValue = new Double(value * 9.0 / 5 + 32);
            break;

          case ITEM_KELVIN:
            newValue = new Double(value + 273.15);

            if (newValue < 0.0)
            {
              this.textOffScale.setVisibility(View.VISIBLE);
              return "*" + newValue.toString(); //$NON-NLS-1$
            }
            break;
        }
        break;

      case ITEM_FAHRENHEIT:
        switch (itemId2)
        {
          case ITEM_CELSIUS:
            newValue = new Double((value - 32) * 5.0 / 9);
            break;

          case ITEM_KELVIN:
            newValue = new Double((value + 459.67) * 5.0 / 9);

            if (newValue < 0.0)
            {
              this.textOffScale.setVisibility(View.VISIBLE);
              return "*" + newValue.toString(); //$NON-NLS-1$
            }
            break;
        }
        break;

      case ITEM_KELVIN:
        switch (itemId2)
        {
          case ITEM_CELSIUS:
            newValue = new Double(value - 273.15);
            break;

          case ITEM_FAHRENHEIT:
            newValue = new Double(value * 9.0 / 5 - 459.67);
            break;
        }

        if (value < 0.0)
        {
          this.textOffScale.setVisibility(View.VISIBLE);
          return "*" + newValue.toString(); //$NON-NLS-1$
        }
        break;
    }

    return newValue.toString();
  }
}