package com.loopj.android.http;

import android.util.Log;

import org.apache.http.Header;

import java.io.UnsupportedEncodingException;

/**
 * Used to intercept and handle the responses from requests made using {@link AsyncHttpClient}. The
 * {@link #onSuccess(int, org.apache.http.Header[], String)} method is designed to be anonymously
 * overridden with your own response handling code. <p> </p> Additionally, you can override the
 * {@link #onFailure(int, org.apache.http.Header[], String, Throwable)}, {@link #onStart()}, and
 * {@link #onFinish()} methods as required. <p> </p> For example: <p> </p>
 * <pre>
 * AsyncHttpClient client = new AsyncHttpClient();
 * client.get("http://www.google.com", new TextHttpResponseHandler() {
 *     @Override
 *     public void onStart() {
 *         // Initiated the request
 *     }
 *
 *     @Override
 *     public void onSuccess(String responseBody) {
 *         // Successfully got a response
 *     }
 *
 *     @Override
 *     public void onFailure(String responseBody, Throwable e) {
 *         // Response failed :(
 *     }
 *
 *     @Override
 *     public void onFinish() {
 *         // Completed the request (either success or failure)
 *     }
 * });
 * </pre>
 */
public abstract class TextHttpResponseHandler extends AsyncHttpResponseHandler {
    private static final String LOG_TAG = "TextHttpResponseHandler";

    /**
     * Creates new instance with default UTF-8 encoding
     */
    public TextHttpResponseHandler() {
        this(DEFAULT_CHARSET);
    }

    /**
     * Creates new instance with given string encoding
     *
     * @param encoding String encoding, see {@link #setCharset(String)}
     */
    public TextHttpResponseHandler(String encoding) {
        super();
        setCharset(encoding);
    }

    /**
     * Called when request fails
     *
     * @param statusCode     http response status line
     * @param headers        response headers if any
     * @param responseString string response of given charset
     * @param throwable      throwable returned when processing request
     */
    public abstract void onFailure(int statusCode, Header[] headers, String responseString, Throwable throwable);

    /**
     * Called when request succeeds
     *
     * @param statusCode     http response status line
     * @param headers        response headers if any
     * @param responseString string response of given charset
     */
    public abstract void onSuccess(int statusCode, Header[] headers, String responseString);

    @Override
    public void onSuccess(int statusCode, Header[] headers, byte[] responseBytes) {
        onSuccess(statusCode, headers, getResponseString(responseBytes, getCharset()));
    }

    @Override
    public void onFailure(int statusCode, Header[] headers, byte[] responseBytes, Throwable throwable) {
        onFailure(statusCode, headers, getResponseString(responseBytes, getCharset()), throwable);
    }

    /**
     * Attempts to encode response bytes as string of set encoding
     *
     * @param charset     charset to create string with
     * @param stringBytes response bytes
     * @return String of set encoding or null
     */
    public static String getResponseString(byte[] stringBytes, String charset) {
        try {
            return stringBytes == null ? null : new String(stringBytes, charset);
        } catch (UnsupportedEncodingException e) {
            Log.e(LOG_TAG, "Encoding response into string failed", e);
            return null;
        }
    }

}