package com.example.testapp.app;

import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemSelectedListener;
import android.widget.Spinner;
import android.widget.ArrayAdapter;
import android.widget.TextView;
import android.widget.EditText;
import android.widget.Button;

public class MainActivity extends ActionBarActivity {
    private TextView textResult;
    private EditText inputValue;
    private Button convertButton;
    private Spinner spinnerCategories, spinnerValue1, spinnerValue2;
    private Unit[] spinnerTemperatureUnits = {
            new Unit("Celsius", 1f),
            new Unit("Kelvin", 1f),
            new Unit("Fahrenheit", 1f)
    };
    private Unit[] spinnerLengthUnits = {
            new Unit("Centimetres", 1f),
            new Unit("Millimetres", 0.1f),
            new Unit("Metres", 100f),
            new Unit("Kilometres", 100000f),
            new Unit("Miles", 160934f),
            new Unit("Feet", 30.48f),
            new Unit("Inches", 2.54f)
    };
    private Unit[] spinnerVolumeUnits = {
            new Unit("Cubic Meters", 1f),
            new Unit("Litres", 0.001f),
            new Unit("Cubic Kilometres", 1000000000f),
            new Unit("Gallons", 264.172f)
    };
    private Unit[] spinnerWeightUnits = {
            new Unit("Kilos", 1f),
            new Unit("Grams", 0.001f),
            new Unit("Tonnes", 1000f),
            new Unit("Pounds", 0.453592f)
    };


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        inputValue = (EditText) findViewById(R.id.inputValue);
        textResult = (TextView) findViewById(R.id.textResult);
        spinnerCategories = (Spinner) findViewById(R.id.spinnerCategories);
        spinnerValue1 = (Spinner) findViewById(R.id.spinnerValue1);
        spinnerValue2 = (Spinner) findViewById(R.id.spinnerValue2);
        convertButton = (Button) findViewById(R.id.convertButton);

        spinnerCategories.setOnItemSelectedListener(new OnItemSelectedListener() {
            @Override
            public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {updateCategory();}
            @Override
            public void onNothingSelected(AdapterView<?> arg0) {}
        });

        spinnerValue1.setOnItemSelectedListener(new OnItemSelectedListener() {
            @Override
            public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {updateValues();}
            @Override
            public void onNothingSelected(AdapterView<?> arg0) {}
        });

        spinnerValue2.setOnItemSelectedListener(new OnItemSelectedListener() {
            @Override
            public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {updateValues();}
            @Override
            public void onNothingSelected(AdapterView<?> arg0) {}
        });

        convertButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {updateValues();}
        });
    }

    private void fillList(Spinner spinner, Unit[] list) {
        Unit[] units = new Unit[list.length];
        for (int i = 0; i < list.length; i++) units[i] = list[i];
        spinner.setAdapter(new ArrayAdapter<Unit>(this,android.R.layout.simple_spinner_item, units));
    }

    private void updateCategory() {
        switch (spinnerCategories.getSelectedItemPosition()) {
            case 0: // Temperature
                fillList(spinnerValue1, spinnerTemperatureUnits);
                fillList(spinnerValue2, spinnerTemperatureUnits);
                spinnerValue1.setSelection(0); // Celsius
                spinnerValue2.setSelection(2); // Fahrenheit
                break;
            case 1: // Length
                fillList(spinnerValue1, spinnerLengthUnits);
                fillList(spinnerValue2, spinnerLengthUnits);
                spinnerValue1.setSelection(2); // Metres
                spinnerValue2.setSelection(5); // Feet
                break;
            case 2: // Volume
                fillList(spinnerValue1, spinnerVolumeUnits);
                fillList(spinnerValue2, spinnerVolumeUnits);
                spinnerValue1.setSelection(0); // Litres
                spinnerValue2.setSelection(3); // Gallons
                break;
            case 3: // Weight
                fillList(spinnerValue1, spinnerWeightUnits);
                fillList(spinnerValue2, spinnerWeightUnits);
                spinnerValue1.setSelection(0); // Kilos
                spinnerValue2.setSelection(3); // Pounds
                break;
        }
        updateValues();
    }
    private void updateValues() {
        float input = Float.parseFloat(inputValue.getText().toString());
        float result = input;
        int fromNumber = spinnerValue1.getSelectedItemPosition(), toNumber = spinnerValue2.getSelectedItemPosition();
        switch (spinnerCategories.getSelectedItemPosition()) {
            case 0:
                if (fromNumber == 0 && toNumber == 1) result = input + 273.15f; // Celsius->Kelvin
                else if (fromNumber == 0 && toNumber == 2) result = input / (5f / 9f) + 32f; // Celsius->Fahrenheit
                else if (fromNumber == 1 && toNumber == 0) result = input - 273.15f; // Kelvin->Celsius
                else if (fromNumber == 1 && toNumber == 2) result = (input - 32f) * (5f / 9f) + 273.15f; // Kelvin->Fahrenheit
                else if (fromNumber == 2 && toNumber == 0) result = (5f / 9f) * (input - 32f); // Fahrenheit->Celsius
                else if (fromNumber == 2 && toNumber == 1) result = (input + 459.67f) * (5f / 9f); // Fahrenheit->Celsius
                break;
            case 1: result = (input * spinnerLengthUnits[fromNumber].getRatio()) / spinnerLengthUnits[toNumber].getRatio(); break;
            case 2: result = (input * spinnerVolumeUnits[fromNumber].getRatio()) / spinnerVolumeUnits[toNumber].getRatio(); break;
            case 3: result = (input * spinnerWeightUnits[fromNumber].getRatio()) / spinnerWeightUnits[toNumber].getRatio(); break;
        }
        textResult.setText(Float.toString(result));
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {

        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();
        if (id == R.id.action_settings) {
            return true;
        }
        return super.onOptionsItemSelected(item);
    }
}