/*********************************************************************
 * $Id: YCallbackHub.java 35436 2019-05-14 15:00:48Z seb $
 *
 * Internal YHTTPHUB object
 *
 * - - - - - - - - - License information: - - - - - - - - -
 *
 * Copyright (C) 2011 and beyond by Yoctopuce Sarl, Switzerland.
 *
 * Yoctopuce Sarl (hereafter Licensor) grants to you a perpetual
 * non-exclusive license to use, modify, copy and integrate this
 * file into your software for the sole purpose of interfacing
 * with Yoctopuce products.
 *
 * You may reproduce and distribute copies of this file in
 * source or object form, as long as the sole purpose of this
 * code is to interface with Yoctopuce products. You must retain
 * this notice in the distributed source file.
 *
 * You should refer to Yoctopuce General Terms and Conditions
 * for additional information regarding your rights and
 * obligations.
 *
 * THE SOFTWARE AND DOCUMENTATION ARE PROVIDED 'AS IS' WITHOUT
 * WARRANTY OF ANY KIND, EITHER EXPRESS OR IMPLIED, INCLUDING
 * WITHOUT LIMITATION, ANY WARRANTY OF MERCHANTABILITY, FITNESS
 * FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO
 * EVENT SHALL LICENSOR BE LIABLE FOR ANY INCIDENTAL, SPECIAL,
 * INDIRECT OR CONSEQUENTIAL DAMAGES, LOST PROFITS OR LOST DATA,
 * COST OF PROCUREMENT OF SUBSTITUTE GOODS, TECHNOLOGY OR
 * SERVICES, ANY CLAIMS BY THIRD PARTIES (INCLUDING BUT NOT
 * LIMITED TO ANY DEFENSE THEREOF), ANY CLAIMS FOR INDEMNITY OR
 * CONTRIBUTION, OR OTHER SIMILAR COSTS, WHETHER ASSERTED ON THE
 * BASIS OF CONTRACT, TORT (INCLUDING NEGLIGENCE), BREACH OF
 * WARRANTY, OR OTHERWISE.
 *********************************************************************/

package com.yoctopuce.YoctoAPI;


import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Set;

class YCallbackHub extends YGenericHub
{
    private final HTTPParams _http_params;
    private final OutputStream _out;
    private YJSONObject _callbackCache;

    YCallbackHub(YAPIContext yctx, int idx, HTTPParams httpParams, InputStream request, OutputStream response) throws YAPI_Exception
    {
        super(yctx, httpParams, idx, true);
        _http_params = httpParams;
        _out = response;
        if (request == null || _out == null) {
            throw new YAPI_Exception(YAPI.INVALID_ARGUMENT, "Use RegisterHub(String url, BufferedReader request, PrintWriter response) to start api in callback");
        }
        try {
            loadCallbackCache(request);
        } catch (IOException ex) {
            throw new YAPI_Exception(YAPI.IO_ERROR, ex.getLocalizedMessage());
        }
    }

    @Override
    void release()
    {
    }

    @Override
    String getRootUrl()
    {
        return _http_params.getUrl();
    }

    @Override
    synchronized boolean isSameHub(String url, Object request, Object response, Object session)
    {
        HTTPParams params = new HTTPParams(url);
        OutputStream tmp = (OutputStream) response;
        return params.getUrl().equals(_http_params.getUrl()) && tmp == _out;
    }

    @Override
    void startNotifications() throws YAPI_Exception
    {
        // nothing to do since there is no notification
        // in this mode
    }

    @Override
    void stopNotifications()
    {
        // nothing to do since there is no notification
        // in this mode
    }

    private void _output(String msg) throws IOException
    {
        _out.write(msg.getBytes(_yctx._deviceCharset));
    }

    private void loadCallbackCache(InputStream in) throws YAPI_Exception, IOException
    {
        ByteArrayOutputStream buffer = new ByteArrayOutputStream();

        int nRead;
        byte[] data = new byte[16384];

        while ((nRead = in.read(data, 0, data.length)) != -1) {
            buffer.write(data, 0, nRead);
        }
        buffer.flush();
        String data_str = buffer.toString(_yctx._defaultEncoding);

        if (data_str.length() == 0) {
            String errmsg = "RegisterHub(callback) used without posting YoctoAPI data";
            _output("\n!YoctoAPI:" + errmsg + "\n");
            _callbackCache = null;
            throw new YAPI_Exception(YAPI.IO_ERROR, errmsg);
        } else {
            try {
                _callbackCache = new YJSONObject(data_str);
                _callbackCache.parse();
            } catch (Exception ex) {
                String errmsg = "invalid data:[\n" + ex.toString() + data_str + "\n]";
                _output("\n!YoctoAPI:" + errmsg + "\n");
                _callbackCache = null;
                throw new YAPI_Exception(YAPI.IO_ERROR, errmsg);
            }
            if (!_http_params.getPass().equals("")) {
                MessageDigest mdigest;
                try {
                    mdigest = MessageDigest.getInstance("MD5");
                } catch (NoSuchAlgorithmException ex) {
                    throw new YAPI_Exception(YAPI.NOT_SUPPORTED, "No MD5 provider");
                }

                // callback data signed, verify signature
                if (!_callbackCache.has("sign")) {
                    String errmsg = "missing signature from incoming YoctoHub (callback password required)";
                    _output("\n!YoctoAPI:" + errmsg + "\n");
                    _callbackCache = null;
                    throw new YAPI_Exception(YAPI.UNAUTHORIZED, errmsg);
                }
                String sign = _callbackCache.getString("sign");
                String pass = _http_params.getPass();
                String salt;
                if (pass.length() == 32) {
                    salt = pass.toLowerCase();
                } else {
                    mdigest.reset();
                    mdigest.update(pass.getBytes(_yctx._deviceCharset));
                    byte[] md5pass = mdigest.digest();
                    salt = YAPIContext._bytesToHexStr(md5pass, 0, md5pass.length).toLowerCase();
                }

                data_str = data_str.replace(sign, salt);
                mdigest.reset();
                mdigest.update(data_str.getBytes(_yctx._deviceCharset));
                byte[] md5 = mdigest.digest();
                String check = YAPIContext._bytesToHexStr(md5, 0, md5.length).toLowerCase();
                if (!check.equals(sign)) {
                    String errmsg = "invalid signature from incoming YoctoHub (invalid callback password)";
                    _output("\n!YoctoAPI:" + errmsg + "\n");
                    _callbackCache = null;
                    throw new YAPI_Exception(YAPI.UNAUTHORIZED, errmsg);
                }
            }
        }
    }

    @SuppressWarnings("RedundantThrows")
    private byte[] cachedRequest(String query, byte[] header_and_body) throws YAPI_Exception, IOException
    {
        // apply POST remotely
        int endline = query.indexOf("\r");
        if (endline >= 0) {
            query = query.substring(0, endline);
        }

        if (query.startsWith("POST ")) {
            String boundary = "???";
            int body_start = YAPIContext._find_in_bytes(header_and_body, "\r\n\r\n".getBytes(_yctx._deviceCharset)) + 4;
            int endb;
            for (endb = body_start; endb < header_and_body.length; endb++) {
                if (header_and_body[endb] == 13) break;
            }
            String tmp = new String(header_and_body, body_start, 2);
            if (tmp.equals("--") && endb > body_start + 2 && endb < body_start + 20) {
                boundary = new String(header_and_body, body_start + 2, endb - body_start - 2);
            }
            int bodylen = header_and_body.length - body_start;
            _output("\n@YoctoAPI:" + query + " " + Integer.toString(bodylen) + ":" + boundary + "\n");
            _out.write(header_and_body, body_start, bodylen);
            return "".getBytes(_yctx._deviceCharset);
        }
        if (!query.startsWith("GET "))
            return null;
        // remove JZON trigger if present (not relevant in callback mode)
        int jzon = query.indexOf("?fw=");
        if (jzon >= 0 && query.indexOf('&', jzon) < 0) {
            query = query.substring(0, jzon);
        }
        // dispatch between cached get and remote set
        if (!query.contains("?") ||
                query.contains("/logs.txt") ||
                query.contains("/logger.json") ||
                query.contains("/ping.txt") ||
                query.contains("/files.json?a=dir")) {
            try {
                // read request, load from cache
                String[] parts = query.split(" ");
                String url = parts[1];
                boolean getmodule = url.contains("api/module.json");
                if (getmodule) {
                    url = url.replace("api/module.json", "api.json");
                }
                if (!_callbackCache.has(url)) {
                    _output("\n!YoctoAPI:" + url + " is not preloaded, adding to list");
                    _output("\n@YoctoAPI:+" + url + "\n");
                    return null;
                }
                YJSONObject jsonres = _callbackCache.getYJSONObject(url);
                if (getmodule) {
                    jsonres = jsonres.getYJSONObject("module");
                }
                return jsonres.toJSON().getBytes(_yctx._deviceCharset);
            } catch (Exception ex) {
                return "".getBytes();
            }
        } else {
            // change request, print to output stream
            _output("\n@YoctoAPI:" + query + "\n");
            return "".getBytes(_yctx._deviceCharset);
        }
    }


    @Override
    synchronized void updateDeviceList(boolean forceupdate) throws YAPI_Exception
    {

        long now = YAPI.GetTickCount();
        if (forceupdate) {
            _devListExpires = 0;
        }
        if (_devListExpires > now) {
            return;
        }
        String yreq;
        try {
            byte[] data = cachedRequest("GET /api.json\r\n", null);
            if (data == null) {
                throw new YAPI_Exception(YAPI.IO_ERROR, "no cached request for GET /api.json");
            }
            yreq = new String(data);
        } catch (IOException ex) {
            throw new YAPI_Exception(YAPI.IO_ERROR, ex.getLocalizedMessage());
        }
        HashMap<String, ArrayList<YPEntry>> yellowPages = new HashMap<>();
        ArrayList<WPEntry> whitePages = new ArrayList<>();
        YJSONObject loadval;
        try {
            loadval = new YJSONObject(yreq);
            loadval.parse();
            if (!loadval.has("services") || !loadval.getYJSONObject("services").has("whitePages")) {
                throw new YAPI_Exception(YAPI.INVALID_ARGUMENT, "Device "
                        + _http_params.getHost() + " is not a hub");
            }

            YJSONArray whitePages_json = loadval.getYJSONObject("services").getYJSONArray("whitePages");
            YJSONObject yellowPages_json = loadval.getYJSONObject("services").getYJSONObject("yellowPages");

            // Reindex all functions from yellow pages
            //HashMap<String, Boolean> refresh = new HashMap<String, Boolean>();
            Set<String> keys = yellowPages_json.getKeys();
            for(String classname : keys){
                YJSONArray yprecs_json = yellowPages_json.getYJSONArray(classname);
                ArrayList<YPEntry> yprecs_arr = new ArrayList<>(
                        yprecs_json.length());
                for (int i = 0; i < yprecs_json.length(); i++) {
                    YPEntry yprec = new YPEntry(yprecs_json.getYJSONObject(i));
                    yprecs_arr.add(yprec);
                }
                yellowPages.put(classname, yprecs_arr);
            }

            // Reindex all devices from white pages
            for (int i = 0; i < whitePages_json.length(); i++) {
                YJSONObject jsonObject = whitePages_json.getYJSONObject(i);
                WPEntry devinfo = new WPEntry(jsonObject);
                int index = jsonObject.getInt("index");
                _serialByYdx.put(index, devinfo.getSerialNumber());
                whitePages.add(devinfo);
            }
        } catch (Exception e) {
            throw new YAPI_Exception(YAPI.IO_ERROR,
                    "Request failed, could not parse API result for "
                            + _http_params.getHost(), e);
        }
        updateFromWpAndYp(whitePages, yellowPages);

        // reset device list cache timeout for this hub
        now = YAPI.GetTickCount();
        _devListExpires = now + 500;
    }

    @Override
    public ArrayList<String> getBootloaders() throws YAPI_Exception
    {
        throw new YAPI_Exception(YAPI.NOT_SUPPORTED, "Firmware update is not supported in HTTP callback");
    }

    @Override
    public int ping(int mstimeout) throws YAPI_Exception
    {
        throw new YAPI_Exception(YAPI.NOT_SUPPORTED, "Not yet implemented");
    }

    @Override
    boolean isCallbackMode()
    {
        return true;
    }

    @Override
    boolean isReadOnly()
    {
        return false;
    }

    @Override
    ArrayList<String> firmwareUpdate(String serial, YFirmwareFile firmware, byte[] settings, UpdateProgress progress) throws YAPI_Exception, InterruptedException
    {
        throw new YAPI_Exception(YAPI.NOT_SUPPORTED, "Firmware update is not supported in HTTP callback");
    }


    @Override
    void devRequestAsync(YDevice device, String req_first_line, byte[] req_head_and_body, RequestAsyncResult asyncResult, Object asyncContext) throws YAPI_Exception
    {
        try {
            cachedRequest(req_first_line, req_head_and_body);
        } catch (IOException ex) {
            throw new YAPI_Exception(YAPI.IO_ERROR, ex.getLocalizedMessage());
        }
    }

    @Override
    byte[] devRequestSync(YDevice device, String req_first_line, byte[] req_head_and_body, RequestProgress progress, Object context) throws YAPI_Exception
    {
        try {
            return cachedRequest(req_first_line, req_head_and_body);
        } catch (IOException ex) {
            throw new YAPI_Exception(YAPI.IO_ERROR, ex.getLocalizedMessage());
        }
    }
}
