package com.example.android.sunshine.app;

import android.net.Uri;
import android.os.AsyncTask;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.text.format.Time;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.ListView;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Arrays;

/**
 * A forecast fragment containing a simple view.
 */
public class ForecastFragment extends Fragment {

    public ForecastFragment() {
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        // Add this line in order for this fragment to handle menu events.
        setHasOptionsMenu(true);
    }

    @Override
    public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
        // Inflate the menu; this adds items to the action bar if it is present.
        inflater.inflate(R.menu.forecastfragment, menu);
    }

    @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();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_refresh) {
            FetchWeatherTask fetchWeatherTask = new FetchWeatherTask();
            fetchWeatherTask.execute("94043");
            return true;
        }

        return super.onOptionsItemSelected(item);
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        View rootView = inflater.inflate(R.layout.fragment_main, container, false);
        ArrayList<String> weekForecast = new ArrayList<>
                (Arrays.asList("Mumbai - Sunny, 30/26",
                        "Mumbai - Sunny, 31/29",
                        "Mumbai - Sunny, 35/26",
                        "Mumbai - Sunny, 34/26.5",
                        "Mumbai - Sunny, 36/30"));
        // Now that we have some dummy forecast data, create an ArrayAdapter.
        // The ArrayAdapter will take data from a source (like our dummy forecast) and
        // use it to populate the ListView it's attached to.
        ArrayAdapter<String> arrayAdapter = new ArrayAdapter<>(getActivity(), R.layout.list_item_forecast, R.id.list_item_forecast_textview, weekForecast);
        // Get a reference to the ListView, and attach this adapter to it.
        ListView listView = (ListView) rootView.findViewById(R.id.listview_forecast);
        listView.setAdapter(arrayAdapter);

        return rootView;
    }
}

class FetchWeatherTask extends AsyncTask<String, Void, String[]> {
    private final String LOG_TAG = FetchWeatherTask.class.getSimpleName();

    /* The date/time conversion code is going to be moved outside the asynctask later,
     * so for convenience we're breaking it out into its own method now.
     */
    private String getReadableDateString(long time) {
        // Because the API returns a unix timestamp (measured in seconds),
        // it must be converted to milliseconds in order to be converted to valid date.
        SimpleDateFormat shortenedDateFormat = new SimpleDateFormat("EEE MMM dd");
        return shortenedDateFormat.format(time);
    }

    /**
     * Prepare the weather high/lows for presentation.
     */
    private String formatHighLows(double high, double low) {
        // For presentation, assume the user doesn't care about tenths of a degree.
        long roundedHigh = Math.round(high);
        long roundedLow = Math.round(low);

        String highLowStr = roundedHigh + "/" + roundedLow;
        return highLowStr;
    }

    /**
     * Take the String representing the complete forecast in JSON Format and
     * pull out the data we need to construct the Strings needed for the wireframes.
     * <p/>
     * Fortunately parsing is easy:  constructor takes the JSON string and converts it
     * into an Object hierarchy for us.
     */
    private String[] getWeatherDataFromJson(String forecastJsonStr, int numDays)
            throws JSONException {

        // These are the names of the JSON objects that need to be extracted.
        final String OWM_LIST = "list";
        final String OWM_WEATHER = "weather";
        final String OWM_TEMPERATURE = "temp";
        final String OWM_MAX = "max";
        final String OWM_MIN = "min";
        final String OWM_DESCRIPTION = "main";

        JSONObject forecastJson = new JSONObject(forecastJsonStr);
        JSONArray weatherArray = forecastJson.getJSONArray(OWM_LIST);

        // OWM returns daily forecasts based upon the local time of the city that is being
        // asked for, which means that we need to know the GMT offset to translate this data
        // properly.

        // Since this data is also sent in-order and the first day is always the
        // current day, we're going to take advantage of that to get a nice
        // normalized UTC date for all of our weather.

        Time dayTime = new Time();
        dayTime.setToNow();

        // we start at the day returned by local time. Otherwise this is a mess.
        int julianStartDay = Time.getJulianDay(System.currentTimeMillis(), dayTime.gmtoff);

        // now we work exclusively in UTC
        dayTime = new Time();

        String[] resultStrs = new String[numDays];
        for (int i = 0; i < weatherArray.length(); i++) {
            // For now, using the format "Day, description, hi/low"
            String day;
            String description;
            String highAndLow;

            // Get the JSON object representing the day
            JSONObject dayForecast = weatherArray.getJSONObject(i);

            // The date/time is returned as a long.  We need to convert that
            // into something human-readable, since most people won't read "1400356800" as
            // "this saturday".
            long dateTime;
            // Cheating to convert this to UTC time, which is what we want anyhow
            dateTime = dayTime.setJulianDay(julianStartDay + i);
            day = getReadableDateString(dateTime);

            // description is in a child array called "weather", which is 1 element long.
            JSONObject weatherObject = dayForecast.getJSONArray(OWM_WEATHER).getJSONObject(0);
            description = weatherObject.getString(OWM_DESCRIPTION);

            // Temperatures are in a child object called "temp".  Try not to name variables
            // "temp" when working with temperature.  It confuses everybody.
            JSONObject temperatureObject = dayForecast.getJSONObject(OWM_TEMPERATURE);
            double high = temperatureObject.getDouble(OWM_MAX);
            double low = temperatureObject.getDouble(OWM_MIN);

            highAndLow = formatHighLows(high, low);
            resultStrs[i] = day + " - " + description + " - " + highAndLow;
        }

        for (String s : resultStrs) {
            Log.v(LOG_TAG, "Forecast entry: " + s);
        }
        return resultStrs;

    }
    @Override
    protected String[] doInBackground(String... params) {

        // If there's no zip code, there's nothing to look up.  Verify size of params.
        if (params.length == 0) {
            return null;
        }

        // These two need to be declared outside the try/catch
        // so that they can be closed in the finally block.
        HttpURLConnection urlConnection = null;
        BufferedReader reader = null;

        // Will contain the raw JSON response as a string.
        String forecastJsonStr = null;
        int numDays = 7;

        try {
            // Construct the URL for the OpenWeatherMap query
            // Possible parameters are available at OWM's forecast API page, at
            // http://openweathermap.org/API#forecast

            Uri.Builder builder = new Uri.Builder();
            builder.scheme("http")
                    .authority("api.openweathermap.org")
                    .appendPath("data")
                    .appendPath("2.5")
                    .appendPath("forecast")
                    .appendPath("daily")
                    .appendQueryParameter("q", params[0])
                    .appendQueryParameter("mode", "json")
                    .appendQueryParameter("units", "metric")
                    .appendQueryParameter("cnt", Integer.toString(numDays))
                    .appendQueryParameter("appid", BuildConfig.OPEN_WEATHER_MAP_API_KEY);

            URL url = new URL(builder.build().toString());
            Log.v(LOG_TAG, url.toString());

            // Create the request to OpenWeatherMap, and open the connection
            urlConnection = (HttpURLConnection) url.openConnection();
            urlConnection.setRequestMethod("GET");
            urlConnection.connect();

            // Read the input stream into a String
            InputStream inputStream = urlConnection.getInputStream();
            StringBuffer buffer = new StringBuffer();
            if (inputStream == null) {
                // Nothing to do.
                return null;
            }
            reader = new BufferedReader(new InputStreamReader(inputStream));

            String line;
            while ((line = reader.readLine()) != null) {
                // Since it's JSON, adding a newline isn't necessary (it won't affect parsing)
                // But it does make debugging a *lot* easier if you print out the completed
                // buffer for debugging.
                buffer.append(line + "\n");
            }

            if (buffer.length() == 0) {
                // Stream was empty.  No point in parsing.
                return null;
            }
            forecastJsonStr = buffer.toString();
            //Log.v(LOG_TAG, "Forecast string: " + forecastJsonStr);
        } catch (IOException e) {
            Log.e(LOG_TAG, "Error ", e);
            // If the code didn't successfully get the weather data, there's no point in attempting
            // to parse it.
            return null;
        } finally {
            if (urlConnection != null) {
                urlConnection.disconnect();
            }
            if (reader != null) {
                try {
                    reader.close();
                } catch (final IOException e) {
                    Log.e(LOG_TAG, "Error closing stream", e);
                }
            }
        }

        try {
            return getWeatherDataFromJson(forecastJsonStr, numDays);
        } catch (JSONException e) {
            Log.e(LOG_TAG, e.getMessage(), e);
            e.printStackTrace();
        }
        // This will only happen if there was an error getting or parsing the forecast.
        return null;
    }
}