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 de.pointedears.converter.R;

/**
 * Activity that implements length conversion
 * 
 * @author pelinux
 */
public class LengthsActivity extends Activity
{
  /*
   * Constants for mapping value strings to internal IDs
   */
  private static final String VALUE_INCHES = "inch"; //$NON-NLS-1$
  private static final String VALUE_KILOMETERS = "km"; //$NON-NLS-1$
  private static final String VALUE_METERS = "m"; //$NON-NLS-1$
  private static final String VALUE_MILES = "mi"; //$NON-NLS-1$
  private static final int ITEM_INCHES = 0;
  private static final int ITEM_KILOMETERS = 1;
  private static final int ITEM_METERS = 2;
  private static final int ITEM_MILES = 3;

  /**
   * Maps value strings to internal IDs
   */
  private final static HashMap<String, Integer> valueToId =
    new HashMap<String, Integer>();
  static
  {
    LengthsActivity.valueToId.put(LengthsActivity.VALUE_INCHES,
      LengthsActivity.ITEM_INCHES);
    LengthsActivity.valueToId.put(LengthsActivity.VALUE_KILOMETERS,
      LengthsActivity.ITEM_KILOMETERS);
    LengthsActivity.valueToId.put(LengthsActivity.VALUE_METERS,
      LengthsActivity.ITEM_METERS);
    LengthsActivity.valueToId.put(LengthsActivity.VALUE_MILES,
      LengthsActivity.ITEM_MILES);
  }

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

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

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

    final EditText editValue1 = (EditText) this.findViewById(R.id.edit_value1);
    final EditText editValue2 = (EditText) this.findViewById(R.id.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 = LengthsActivity.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 = LengthsActivity.this.getConvertedValue(value2, true);
        }

        editValue1.setText(string1);

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

    this.spinnerUnit1 = (Spinner) this.findViewById(R.id.spinner_unit1);
    this.spinnerUnit2 = (Spinner) this.findViewById(R.id.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.lengths_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.length_units_values);
    String selectedItemValue1 = itemArray[selectedItemPosition1];
    String selectedItemValue2 = itemArray[selectedItemPosition2];

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

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

    Double newValue = value;

    switch (itemId1)
    {
      case ITEM_INCHES:
        switch (itemId2)
        {
          case ITEM_KILOMETERS:
            /* see ITEM_METERS */
            newValue = new Double((value * 0.0254) / 1000);
            break;

          case ITEM_METERS:
            newValue = new Double(value * 0.0254);
            break;

          case ITEM_MILES:
            /* 12 in/ft and 5280 ft/mi */
            newValue = new Double(value / 12 / 5280);
            break;
        }
        break;

      case ITEM_KILOMETERS:
        switch (itemId2)
        {
          case ITEM_INCHES:
            /* 1 m = 39.370 in */
            newValue = new Double(value * 1000 * 39.370);
            break;

          case ITEM_METERS:
            newValue = new Double(value * 1000);
            break;

          case ITEM_MILES:
            newValue = new Double(value / 1.609344);
            break;
        }
        break;

      case ITEM_METERS:
        switch (itemId2)
        {
          case ITEM_INCHES:
            /* 1 m = 39.370 in */
            newValue = new Double(value * 39.370);
            break;

          case ITEM_KILOMETERS:
            newValue = new Double(value / 1000);
            break;

          case ITEM_MILES:
            /* 1 mi = 1609.344 m */
            newValue = new Double(value / 1609.344);
            break;
        }
        break;

      case ITEM_MILES:
        switch (itemId2)
        {
          case ITEM_INCHES:
            /* 1 mi = 5280 ft, 1 ft = 12 in */
            newValue = new Double(value * 5280 * 12);
            break;

          case ITEM_KILOMETERS:
            newValue = new Double(value * 1.609344);
            break;

          case ITEM_METERS:
            newValue = new Double(value * 1609.344);
            break;
        }
        break;
    }

    return newValue.toString();
  }
}