package com.klippa.NativeScriptHTTP;

import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.util.Log;

import java.io.BufferedInputStream;
import java.io.ByteArrayOutputStream;
import java.io.Closeable;
import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.Locale;
import java.util.Stack;
import java.util.concurrent.LinkedBlockingQueue;
import java.util.concurrent.ThreadFactory;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;

import okhttp3.Call;
import okhttp3.Callback;
import okhttp3.CertificatePinner;
import okhttp3.Headers;
import okhttp3.MediaType;
import okhttp3.OkHttpClient;
import okhttp3.Request;
import okhttp3.RequestBody;
import okhttp3.Response;
import okhttp3.ResponseBody;
import okhttp3.WebSocket;
import okhttp3.WebSocketListener;

public class Async {
    static final String TAG = "Async";
    static ThreadPoolExecutor executor = null;

    static ThreadPoolExecutor threadPoolExecutor() {
        if (executor == null) {
            int NUMBER_OF_CORES = Runtime.getRuntime().availableProcessors();
            ThreadFactory backgroundPriorityThreadFactory = new PriorityThreadFactory(android.os.Process.THREAD_PRIORITY_BACKGROUND);

            executor = new ThreadPoolExecutor(
                    NUMBER_OF_CORES * 2,
                    NUMBER_OF_CORES * 2,
                    60L,
                    TimeUnit.SECONDS,
                    new LinkedBlockingQueue<Runnable>(),
                    backgroundPriorityThreadFactory
            );
        }

        return executor;
    }

    public interface CompleteCallback {
        void onComplete(Object result, Object tag);

        void onError(String error, Object tag);
    }

    static class PriorityThreadFactory implements ThreadFactory {
        private final int mThreadPriority;

        public PriorityThreadFactory(int threadPriority) {
            mThreadPriority = threadPriority;
        }

        @Override
        public Thread newThread(final Runnable runnable) {
            Runnable wrapperRunnable = new Runnable() {
                @Override
                public void run() {
                    try {
                        android.os.Process.setThreadPriority(mThreadPriority);
                    } catch (Throwable t) {

                    }
                    runnable.run();
                }
            };
            return new Thread(wrapperRunnable);
        }
    }

    public static class Http {
        private static final String GET_METHOD = "GET";
        private static final String HEAD_METHOD = "HEAD";
        private static OkHttpClient client;
        private static MemoryCookieJar cookieJar;
        private static CertificatePinner.Builder certificatePinnerBuilder;
        private static ImageParseMethod imageParseMethod = ImageParseMethod.CONTENTTYPE;

        public static void InitClient() {
            if (cookieJar == null) {
                cookieJar = new MemoryCookieJar();
            }

            if (client == null) {
                client = new OkHttpClient.Builder()
                        .writeTimeout(60, TimeUnit.SECONDS)
                        .readTimeout(60, TimeUnit.SECONDS)
                        .connectTimeout(60, TimeUnit.SECONDS)
                        .cookieJar(cookieJar)
                        .build();
            }
        }

        public static void MakeRequest(final RequestOptions options, final CompleteCallback callback, final Object context) {
            InitClient();
            final android.os.Handler mHandler = new android.os.Handler();
            threadPoolExecutor().execute(new Runnable() {
                @Override
                public void run() {
                    final HttpRequestTask task = new HttpRequestTask(callback, context);

                    try {
                        final OkHttpClient client = task.buildClient(options);
                        final Request request = task.buildRequest(options);

                        client.newCall(request).enqueue(new Callback() {
                            @Override
                            public void onFailure(Call call, IOException e) {
                                final RequestResult result = new RequestResult();
                                result.error = e;

                                mHandler.post(new Runnable() {
                                    @Override
                                    public void run() {
                                        task.onPostExecute(result);
                                    }
                                });
                            }

                            @Override
                            public void onResponse(Call call, Response response) throws IOException {
                                final RequestResult result = task.parseResponse(response, options);
                                mHandler.post(new Runnable() {
                                    @Override
                                    public void run() {
                                        task.onPostExecute(result);
                                    }
                                });
                            }
                        });
                    } catch(Exception e) {
                        final RequestResult result = new RequestResult();
                        result.error = e;

                        mHandler.post(new Runnable() {
                            @Override
                            public void run() {
                                task.onPostExecute(result);
                            }
                        });
                    }
                }
            });
        }

        public static WebSocket GetWebSocketConnection(final RequestOptions options, final WebSocketListener listener)  {
            InitClient();
            OkHttpClient.Builder clientBuilder = client.newBuilder();

            // don't follow redirect (30x) responses; by default, HttpURLConnection follows them.
            if (options.dontFollowRedirects) {
                clientBuilder.followRedirects(false);
            }

            OkHttpClient client = clientBuilder.build();

            Request.Builder requestBuilder = new Request.Builder();
            requestBuilder.url(options.url);

            if (options.headers != null) {
                for (KeyValuePair pair : options.headers) {
                    String key = pair.key.toString();
                    requestBuilder.addHeader(key, pair.value.toString());
                }
            }

            Request request = requestBuilder.build();
            return client.newWebSocket(request, listener);
        }

        public static void ClearCookies() {
            if (cookieJar != null) {
                cookieJar.clear();
            }
        }

        public static void SetImageParseMethod(ImageParseMethod newImageParseMethod) {
            imageParseMethod = newImageParseMethod;
        }

        public static void SetConcurrencyLimits(int maxRequests, int maxRequestsPerHost) {
            // Make sure we have a client.
            InitClient();

            client.dispatcher().setMaxRequests(maxRequests);
            client.dispatcher().setMaxRequestsPerHost(maxRequestsPerHost);
        }

        public static void PinCertificate(String pattern, String[] hashes) {
            // Make sure we have a client.
            InitClient();

            // Make sure we have a pinner.
            if (certificatePinnerBuilder == null) {
                certificatePinnerBuilder = new CertificatePinner.Builder();
            }

            // Add the pin.
            certificatePinnerBuilder.add(pattern, hashes);

            // Override the certificate pinner of the client.
            client = client.newBuilder().certificatePinner(certificatePinnerBuilder.build()).build();
        }

        public static void RemoveCertificatePins() {
            certificatePinnerBuilder = null;

            // If we had a client, reset the pinner to the default.
            if (client != null) {
                client = client.newBuilder().certificatePinner(CertificatePinner.DEFAULT).build();
            }
        }

        public enum ImageParseMethod {
            NEVER,
            CONTENTTYPE,
            ALWAYS
        }

        public static class KeyValuePair {
            public String key;
            public String value;

            public KeyValuePair(String key, String value) {
                this.key = key;
                this.value = value;
            }
        }

        public static class RequestOptions {
            public String url;
            public String method;
            public ArrayList<KeyValuePair> headers;
            public RequestBody content;
            public int timeout = -1;
            public int screenWidth = -1;
            public int screenHeight = -1;
            public boolean dontFollowRedirects = false;
            public boolean forceImageParsing = false;

            public void addHeaders(Request.Builder requestBuilder) {
                if (this.headers == null) {
                    return;
                }

                for (KeyValuePair pair : this.headers) {
                    String key = pair.key.toString();
                    requestBuilder.addHeader(key, pair.value.toString());
                }
            }
        }

        public static class RequestResult {
            public ByteArrayOutputStream raw;
            public ArrayList<KeyValuePair> headers = new ArrayList<KeyValuePair>();
            public int statusCode;
            public String responseAsString;
            public Bitmap responseAsImage;
            public Exception error;
            public String url;
            public String statusText;

            public void getHeaders(Response response) {
                Headers headers = response.headers();
                if (headers == null) {
                    // no headers, this may happen if there is no internet connection currently available
                    return;
                }

                int size = headers.size();
                if (size == 0) {
                    return;
                }

                for (int i = 0; i < headers.size(); i++) {
                    this.headers.add(new KeyValuePair(headers.name(i), headers.value(i)));
                }
            }

            public void readResponseStream(Response response, Stack<Closeable> openedStreams, RequestOptions options) throws IOException {
                ResponseBody responseBody = response.body();
                if (responseBody == null) {
                    // responseBody can be null in case of no body.
                    return;
                }

                int contentLength = ((int) responseBody.contentLength());
                InputStream inStream = responseBody.byteStream();

                openedStreams.push(inStream);

                BufferedInputStream buffer = new BufferedInputStream(inStream, 4096);
                openedStreams.push(buffer);

                ByteArrayOutputStream2 responseStream = contentLength != -1 ? new ByteArrayOutputStream2(contentLength) : new ByteArrayOutputStream2();
                openedStreams.push(responseStream);

                byte[] buff = new byte[4096];
                int read = -1;
                while ((read = buffer.read(buff, 0, buff.length)) != -1) {
                    responseStream.write(buff, 0, read);
                }

                this.raw = responseStream;
                buff = null;

                MediaType contentType = responseBody.contentType();
                if (options.forceImageParsing || imageParseMethod == ImageParseMethod.ALWAYS || (imageParseMethod == ImageParseMethod.CONTENTTYPE && contentType != null && contentType.toString().startsWith("image/"))) {
                    // make the byte array conversion here, not in the JavaScript
                    // world for better performance
                    try {
                        // TODO: Generally this approach will not work for very
                        // large files
                        BitmapFactory.Options bitmapOptions = new BitmapFactory.Options();
                        bitmapOptions.inJustDecodeBounds = true;

                        // check the size of the bitmap first
                        BitmapFactory.decodeByteArray(responseStream.buf(), 0, responseStream.size(), bitmapOptions);
                        if (bitmapOptions.outWidth > 0 && bitmapOptions.outHeight > 0) {
                            int scale = 1;
                            final int height = bitmapOptions.outHeight;
                            final int width = bitmapOptions.outWidth;

                            if ((options.screenWidth > 0 && bitmapOptions.outWidth > options.screenWidth) ||
                                    (options.screenHeight > 0 && bitmapOptions.outHeight > options.screenHeight)) {
                                final int halfHeight = height / 2;
                                final int halfWidth = width / 2;

                                // scale down the image since it is larger than the
                                // screen resolution
                                while ((halfWidth / scale) > options.screenWidth && (halfHeight / scale) > options.screenHeight) {
                                    scale *= 2;
                                }
                            }

                            bitmapOptions.inJustDecodeBounds = false;
                            bitmapOptions.inSampleSize = scale;
                            this.responseAsImage = BitmapFactory.decodeByteArray(responseStream.buf(), 0, responseStream.size(), bitmapOptions);
                        }
                    } catch (Exception e) {
                        Log.e(TAG, "Failed to decode byte array, Exception: " + e.getMessage());
                    }
                }

                if (this.responseAsImage == null) {
                    // convert to string
                    this.responseAsString = responseStream.toString();
                }
            }

            public static final class ByteArrayOutputStream2 extends ByteArrayOutputStream {
                public ByteArrayOutputStream2() {
                    super();
                }

                public ByteArrayOutputStream2(int size) {
                    super(size);
                }

                /**
                 * Returns the internal buffer of this ByteArrayOutputStream, without copying.
                 */
                public synchronized byte[] buf() {
                    return this.buf;
                }
            }
        }

        static class HttpRequestTask {
            private CompleteCallback callback;
            private Object context;

            public HttpRequestTask(CompleteCallback callback, Object context) {
                this.callback = callback;
                this.context = context;
            }

            protected OkHttpClient buildClient(RequestOptions... params) {
                RequestOptions options = params[0];
                OkHttpClient.Builder clientBuilder = client.newBuilder();
                // apply timeout
                if (options.timeout > 0) {
                    clientBuilder.writeTimeout(options.timeout, TimeUnit.MILLISECONDS);
                    clientBuilder.readTimeout(options.timeout, TimeUnit.MILLISECONDS);
                    clientBuilder.connectTimeout(options.timeout, TimeUnit.MILLISECONDS);
                }

                // don't follow redirect (30x) responses; by default, HttpURLConnection follows them.
                if (options.dontFollowRedirects) {
                    clientBuilder.followRedirects(false);
                }

                return clientBuilder.build();
            }

            protected Request buildRequest(RequestOptions... params) {
                RequestOptions options = params[0];
                Request.Builder requestBuilder = new Request.Builder();
                requestBuilder.url(options.url);

                // set the request method
                String requestMethod = options.method != null ? options.method.toUpperCase(Locale.ENGLISH) : GET_METHOD;
                requestBuilder.method(requestMethod, options.content);

                // add the headers
                options.addHeaders(requestBuilder);

                return requestBuilder.build();
            }

            protected RequestResult parseResponse(Response response, RequestOptions... params) {
                RequestResult result = new RequestResult();
                Stack<Closeable> openedStreams = new Stack<Closeable>();

                try {
                    RequestOptions options = params[0];
                    String requestMethod = options.method != null ? options.method.toUpperCase(Locale.ENGLISH) : GET_METHOD;
                    // build the result
                    result.getHeaders(response);
                    result.url = options.url;
                    result.statusCode = response.code();
                    result.statusText = response.message();
                    if (!requestMethod.equals(HEAD_METHOD)) {
                        result.readResponseStream(response, openedStreams, options);
                    }

                    // close the opened streams (saves copy-paste implementation
                    // in each method that throws IOException)
                    this.closeOpenedStreams(openedStreams);

                    return result;
                } catch (Exception e) // TODO: Catch all exceptions?
                {
                    result.error = e;

                    return result;
                } finally {
                    try {
                        this.closeOpenedStreams(openedStreams);
                    } catch (IOException e) {
                        Log.e(TAG, "Failed to close opened streams, IOException: " + e.getMessage());
                    }
                }
            }

            protected void onPostExecute(final RequestResult result) {
                if (result != null) {
                    this.callback.onComplete(result, this.context);
                } else {
                    this.callback.onError("HttpRequestTask returns no result.", this.context);
                }
            }

            private void closeOpenedStreams(Stack<Closeable> streams) throws IOException {
                while (streams.size() > 0) {
                    Closeable stream = streams.pop();
                    stream.close();
                }
            }
        }
    }
}