/* Copyright (C) 2014 J.F.Dockes

 *     This program is free software; you can redistribute it and/or modify

 *     it under the terms of the GNU General Public License as published by

 *     the Free Software Foundation; either version 2 of the License, or

 *     (at your option) any later version.

 *

 *     This program is distributed in the hope that it will be useful,

 *     but WITHOUT ANY WARRANTY; without even the implied warranty of

 *     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 *     GNU General Public License for more details.

 *

 *     You should have received a copy of the GNU General Public License

 *     along with this program; if not, write to the

 *     Free Software Foundation, Inc.,

 *     59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.

 */

#include "config.h"

#include <string.h>

#include <arpa/inet.h>

#include <sys/types.h>

#include <sys/select.h>

#include <sys/socket.h>

#include <iostream>

#include <queue>

#include <microhttpd.h>

#include "log.h"

#include "rcvqueue.h"

#include "wav.h"

using namespace std;

/** 

   Implement web server to export the audio stream. I had to jump

   through many hoops to get this to work with mpd (probably because

   of audiofile/sndfile restrictions). None of these are necessary

   with VLC which is quite happy if we just serve any wav header

   directly followed by audio data. 

   The trick to get this to work with libsndfile was apparently to

   send a Content-Size header. If we don't, the lib tries to seek

   inside the file (which I tried to emulate by accepting ranges), but

   fails to parse it anyway, which is quite probably a bug in

   libsndfile (does not see files with unknown size often...).

*/

// Only accept HTTP connections from localhost

#define ACCEPT_LOCALONLY 1

static const int dataformat_wav = 1;

#ifndef MIN

#define MIN(A, B) ((A) < (B) ? (A) : (B))

#endif

// The queue for audio blocks out of SongCast

static queue<AudioMessage*> dataqueue;

static PTMutexInit dataqueueLock;

static pthread_cond_t dataqueueWaitCond = PTHREAD_COND_INITIALIZER;

// Bogus data size for our streams. Total size is databytes+44 (header)

const unsigned int databytes = 2 * 1000 * 1000 * 1000;

// Used this while trying to emulate ranges, did not do the trick

struct ReadContext {

    ReadContext(long long o = 0) : baseoffset(o) {}

    long long baseoffset;

};

static const char *ValueKindToCp(enum MHD_ValueKind kind)

{

    switch (kind) {

    case MHD_RESPONSE_HEADER_KIND: return "Response header";

    case MHD_HEADER_KIND: return "HTTP header";

    case MHD_COOKIE_KIND: return "Cookies";

    case MHD_POSTDATA_KIND: return "POST data";

    case MHD_GET_ARGUMENT_KIND: return "GET (URI) arguments";

    case MHD_FOOTER_KIND: return "HTTP footer";

    default: return "Unknown";

    }

}

static int print_out_key (void *cls, enum MHD_ValueKind kind, 

                          const char *key, const char *value)

{

    LOGDEB(ValueKindToCp(kind) << ": " << key << " -> " << value << endl);

    return MHD_YES;

}

// This gets called by microhttpd when it needs data.

static ssize_t

data_generator(void *cls, uint64_t pos, char *buf, size_t max)

{

    ReadContext *rc = (ReadContext *)cls;

    //LOGDEB("data_generator: baseoffs " <<

    //        rc->baseoffset << " pos " << pos << " max " << max << endl);

    if (rc->baseoffset + pos >= databytes + 44) {

        LOGDEB("data_generator: returning EOS" << endl);

        return MHD_CONTENT_READER_END_OF_STREAM;

    }

    PTMutexLocker lock(dataqueueLock);

    size_t bytes = 0;

    while (bytes < max) {

        while (dataqueue.empty()) {

            //LOGDEB("data_generator: waiting for buffer" << endl);

            pthread_cond_wait(&dataqueueWaitCond, lock.getMutex());

            if (!dataqueue.empty() && dataqueue.front()->m_buf == 0) {

                // special buf, to be processed ?

                LOGINF("data_generator: deleting empty buf" << endl);

                delete dataqueue.front();

                dataqueue.pop();

            }

        }

        AudioMessage *m = dataqueue.front();

        if (dataformat_wav && rc->baseoffset == 0 && pos == 0 && bytes == 0) {

            LOGINF("data_generator: first buf" << endl);

            // Using buf+bytes in case we ever insert icy before the audio

            int sz = makewavheader(buf+bytes, max, 

                                   m->m_freq, m->m_bits, m->m_chans, databytes);

            bytes += sz;

        }

        size_t newbytes = MIN(max - bytes, m->m_bytes - m->m_curoffs);

        memcpy(buf + bytes, m->m_buf + m->m_curoffs, newbytes);

        m->m_curoffs += newbytes;

        bytes += newbytes;

        if (m->m_curoffs == m->m_bytes) {

            delete dataqueue.front();

            dataqueue.pop();

        }

    }

    //LOGDEB("data_generator: returning " << bytes << " bytes" << endl);

    return bytes;

}

// Parse range header. 

static void parseRanges(const string& ranges, vector<pair<int,int> >& oranges)

{

    oranges.clear();

    string::size_type pos = ranges.find("bytes=");

    if (pos == string::npos) {

        return;

    }

    pos += 6;

    bool done = false;

    while(!done) {

        string::size_type dash = ranges.find('-', pos);

        string::size_type comma = ranges.find(',', pos);

        string firstPart = dash != string::npos ? 

            ranges.substr(pos, dash-pos) : "";

        int start = firstPart.empty() ? 0 : atoi(firstPart.c_str());

        string secondPart = dash != string::npos ? 

            ranges.substr(dash+1, comma != string::npos ? 

                          comma-dash-1 : string::npos) : "";

        int fin = secondPart.empty() ? -1 : atoi(firstPart.c_str());

        pair<int,int> nrange(start,fin);

        oranges.push_back(nrange);

        if (comma != string::npos) {

            pos = comma + 1;

        }

        done = comma == string::npos;

    }

}

static void ContentReaderFreeCallback(void *cls)

{

    ReadContext *rc = (ReadContext*)cls;

    delete rc;

}

static int answer_to_connection(void *cls, struct MHD_Connection *connection, 

                                const char *url, 

                                const char *method, const char *version, 

                                const char *upload_data, 

                                size_t *upload_data_size, void **con_cls)

{

    LOGDEB("answer_to_connection: url " << url << " method " << method << 

           " version " << version << endl);

    //MHD_get_connection_values(connection, MHD_HEADER_KIND, &print_out_key, 0);

    static int aptr;

    if (&aptr != *con_cls) {

        /* do not respond on first call */

        *con_cls = &aptr;

        return MHD_YES;

    }

    const char* rangeh = MHD_lookup_connection_value(connection, 

                                                    MHD_HEADER_KIND, "range");

    vector<pair<int,int> > ranges;

    if (rangeh) {

        parseRanges(rangeh, ranges);

    }

    long long size = MHD_SIZE_UNKNOWN;

    ReadContext *rc = new ReadContext();

    if (ranges.size()) {

        if (ranges[0].second != -1) {

            size = ranges[0].second - ranges[0].first + 1;

        }

        rc->baseoffset = ranges[0].first;

        //LOGDEB("httpgate: answer: got ranges: baseoffs " << rc->baseoffset <<

        //" sz " << size << endl);

    }

    struct MHD_Response *response = 

        MHD_create_response_from_callback(size, 1764, &data_generator, 

                                          rc, ContentReaderFreeCallback);

    if (response == NULL) {

        LOGERR("httpgate: answer: could not create response" << endl);

        return MHD_NO;

    }

    if (dataformat_wav) {

        MHD_add_response_header (response, "Content-Type", "audio/x-wav");

    } else {

        // Could not get this to work with mpd??

        MHD_add_response_header (response, "Content-Type", 

                                 "audio/x-mpd-cdda-pcm-reverse");

    }

    char cl[30];

    sprintf(cl, "%d", databytes+44);

    MHD_add_response_header (response, "Content-Length", cl);

    MHD_add_response_header (response, "Accept-Ranges", "bytes");

    //MHD_add_response_header (response, "icy-metaint", "32768");

    int ret = MHD_queue_response (connection, MHD_HTTP_OK, response);

    MHD_destroy_response (response);

    return ret;

}

static int accept_policy(void *, const struct sockaddr* sa,

                         socklen_t addrlen)

{

    static struct sockaddr_in localaddr;

    static bool init = false;

    if (!init) {

        inet_pton(AF_INET, "127.0.0.1", &localaddr.sin_addr);

        init = true;

    }

    if (!sa || sa->sa_family != AF_INET) {

        LOGERR("httpgate:accept_policy: not AF_INET" << endl);

        return MHD_NO;

    }

#if ACCEPT_LOCALONLY != 0

    const struct sockaddr_in *sain = (const struct sockaddr_in*)sa;

    if (sain->sin_addr.s_addr != localaddr.sin_addr.s_addr) {

        LOGERR("httpgate:accept_policy: not localhost" << endl);

        return MHD_NO;

    }

#endif

    return MHD_YES;

}

void *audioEater(void *cls)

{

    AudioEaterContext *ctxt = (AudioEaterContext*)cls;

    if (ctxt->port == 0) {

        ctxt->port = 8888;

    }

    LOGDEB("Using port " << ctxt->port << " for HTTP" << endl);

    struct MHD_Daemon *daemon = 

        MHD_start_daemon(

            MHD_USE_THREAD_PER_CONNECTION,

            //MHD_USE_SELECT_INTERNALLY, 

            ctxt->port, 

            /* Accept policy callback and arg */

            accept_policy, NULL, 

            /* handler and arg */

            &answer_to_connection, NULL, 

            MHD_OPTION_END);

    if (NULL == daemon) {

        audioqueue.workerExit();

        return (void *)0;

    }

    delete ctxt;

    for (int seq=0;;seq++) {

        AudioMessage *tsk = 0;

        size_t qsz;

        if (!audioqueue.take(&tsk, &qsz)) {

            MHD_stop_daemon (daemon);

            audioqueue.workerExit();

            return (void*)1;

        }

#if 0        

        if (seq % 200 == 0) {

            LOGDEB("audioEater: msg: " << tsk->m_bytes << " bytes " << endl);

        }

#endif

        PTMutexLocker lock(dataqueueLock);

        /* limit size of queuing. If there is a client but it is not

           eating blocks fast enough, there will be audio pops */

        while (dataqueue.size() > 2) {

            //LOGINF("audioEater: discarding buffer !" << endl);

            delete dataqueue.front();

            dataqueue.pop();

        }

        dataqueue.push(tsk);

        pthread_cond_broadcast(&dataqueueWaitCond);

    }

}