/*
  Copyright 2010 Nathan Phillip Brink, Ethan Zonca, Matthew Orlando

  This file is a part of DistRen.

  DistRen is free software: you can redistribute it and/or modify
  it under the terms of the GNU Affero General Public License as published by
  the Free Software Foundation, either version 3 of the License, or
  (at your option) any later version.

  DistRen 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 Affero General Public License for more details.

  You should have received a copy of the GNU Affero General Public License
  along with DistRen.  If not, see <http://www.gnu.org/licenses/>.

*/

/* This file contains the code which both processes (renders) jobs as a slave, and the code which distributes frames to slaves after receiving them from the client portion of the codebase. */

#include "distrenjob.h"
#include "listen.h"
#include "slavefuncs.h"
#include "mysql.h"

#include "common/asprintf.h"
#include "common/execio.h"
#include "common/options.h"
#include "common/protocol.h"

#include <confuse.h>
#include <malloc.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <time.h>
#include <unistd.h>

#include <libxml/encoding.h>
#include <libxml/parser.h>
#include <libxml/tree.h>
#include <libxml/xmlmemory.h>
#include <libxml/xmlreader.h>
#include <libxml/xmlwriter.h>

/* ******************* Structs ************************ */
struct general_info
{
  struct distrenjob head;
  distrend_mysql_conn_t conn;

  struct distrend_config *config;

  struct
  {
    /** general_info.xml */
    char *geninfo;
    
  } files;

  int jobs_in_queue;
  unsigned int free_clients;
  unsigned int rendering_clients;
  unsigned int total_finished_jobs;
  unsigned int total_frames_rendered;
  unsigned int highest_jobnum;
  int hibernate;
  time_t timestamp;
  unsigned long total_render_power;
  unsigned long total_priority_pieces;
};


/* *********************************************
   Function Prototypes
   ********************************************* */

/* ************General Functions************* */
int distrend_do();
void frame_watchdog(struct distrenjob *distrenjob_head);
int distrend_do_config(int argc, char *argv[], struct distrend_config **config);
int distrend_config_free(struct distrend_config *config);

/* **************XML Functions**************** */
void update_general_info(struct general_info *geninfo);
int import_general_info(struct general_info *general_info);
int update_xml_joblist(struct general_info *geninfo);

/* **************Test Functions**************** */
int interactiveTest(int test, struct general_info *general_info);

/* **************** Main ********************* */
int main(int argc, char *argv[])
{
  /* Parse arguments */
  int counter;
  int test = 0; /*< Interactive mode if 1 */
  struct general_info general_info;
  struct distrend_clientset *clients;

  enum clientstatus
  {
    CLIENTSTATUS_UNINITIALIZED = 0,
    CLIENTSTATUS_BUSY = 1,
    CLIENTSTATUS_IDLE = 2
  } clientstatus;

  clientstatus = CLIENTSTATUS_UNINITIALIZED;
  // xmlinit();

  for(counter = 0; counter < argc; counter ++)
    {
      if(strcmp(argv[counter], "-h") == 0)
      {
    	  fprintf(stderr, "Usage: distrend [option] \nStarts the distrend server\n\t-h\tshow this help\n\t-t\tlaunches queue testing interface \n");
	  return 2;
      }

      else if(strcmp(argv[counter], "-t") == 0)
      {
    	  fprintf(stderr, "Entering into test mode...\n\n");
    	  test = 1;
      }
    }


  if(distrend_do_config(argc, argv, &general_info.config))
    return 1;

  /** preset paths */
  _distren_asprintf(&general_info.files.geninfo, "%s/general_info.xml",
		    general_info.config->datadir);

  /** MySQL Connection */
  fprintf(stderr,"Connecting to mysql...\n");
  if(mysqlConnect(&general_info.conn))
    {
      fprintf(stderr, "%s:%d: mysqlConnect() failed\n", __FILE__, __LINE__);
      fprintf(stderr, "don't test mysql stuff\n");
      interactiveTest(test, &general_info);
      return 1;
    }
  fprintf(stderr,"Finished connecting!\n");

  /** Execute test function */
  interactiveTest(test, &general_info);

  distrend_listen(general_info.config, &clients);

  int slaveKey = 0; // Remotio should set me on a per-slave basis
  /* Main Loop */
  while(!general_info.config->die)
    {
      int clientsays = 0; /*< temporary example variable, will be replaced when we can handle messages */

      distrend_accept(general_info.config, clients);

      /* Make the following code more event-driven */
      frame_watchdog(&general_info.head);

      struct frameset frame;
      struct distrenjob *job;
      distrenjob_new(&job);

      memset(&frame, '\0', sizeof(frame));

      /* If the client is idle, must be modified for climbing through linked list of clients (client->clientnum) */
      if(clientstatus == CLIENTSTATUS_IDLE)
	{
	  int returnnum = find_jobframe(general_info.conn, slaveKey, &job->jobnum, &frame.num); // Finds a frame to render @FIXME: Slavenum :D
	  if(returnnum)
	    {
	      fprintf(stderr,"No frames are available to render at this time. Idling...\n");
	      sleep(10);
	    }
	  else
	    remotio_send_to_client(frame.num, job->jobnum); // Pseudo-sends data to client
	}
      /* If the client states that they finished the frame */
      if(clientsays == DISTREN_REQUEST_DONEFRAME)
	{
	  clientstatus = CLIENTSTATUS_IDLE; // Sets the client back to idle
	  finish_frame(general_info.conn, 0, job->jobnum, frame.num); // @TODO: Make sure this actually works.
	}
      distrenjob_free(&job);
    }

  distrend_unlisten(general_info.config->listens, clients);
  distrend_config_free(general_info.config);

  xmlcleanup();

  /** free() paths */
  free(general_info.files.geninfo);
  mysqlDisconnect(general_info.conn);

  return 0;
}

/* ********************** Functions ************************* */

/**
   Performs command stored in a client's request. @TODO: Fill stub
*/
int distrend_do()
{
  return 0;
}


/** Checks for dead, latent, or stale slaves */
void frame_watchdog(struct distrenjob *distrenjob_head)
{
  // Replace with mysqlness, maybe
  // iterate through jobs
    // if the job has been started, checks by seeing if either to first or second frame has been started
    // FRAMESETSTATUS_UNASSIGNED
      // iterate through all frames for this job:
          //watchdog_forgiveness = seconds of forgiveness before frame is re-assigned:
             //   If frame is not completed within the number of seconds specified by watchdog_forgiveness
             //   Then change the frame status to unassigned
}


/* Grabs config info from confs */
int distrend_do_config(int argc, char *argv[], struct distrend_config **config)
{
  unsigned int counter;

  cfg_opt_t myopts_listen[] =
    {
      CFG_SIMPLE_STR("type", NULL),
      CFG_SIMPLE_STR("path", NULL),
      CFG_SIMPLE_INT("port", NULL),
      CFG_END()
    };
  cfg_opt_t myopts[] =
    {
      CFG_SEC("listen",  /* this must be imported into struct listens (which must still be declared) */
          myopts_listen,
          CFGF_MULTI),
      CFG_SIMPLE_STR("datadir", NULL),
      CFG_STR_LIST("render_types", NULL, CFGF_NONE),
      CFG_END()
    };

  cfg_t *cfg_listen;

  fprintf(stderr, "%s:%d: running config\n", __FILE__, __LINE__);
  *config = malloc(sizeof(struct distrend_config));
  myopts[1].simple_value = &(*config)->datadir;

  if(options_init(argc, argv, &(*config)->mycfg, myopts, "daemon", &(*config)->options))
    return 1;

  /**
     grab listen blocks:
   */
  (*config)->listens = malloc(sizeof(struct distrend_listen) * (cfg_size((*config)->mycfg, "listen") + 1));
  for(counter = 0; counter < cfg_size((*config)->mycfg, "listen"); counter ++)
    {
      cfg_listen = cfg_getnsec((*config)->mycfg, "listen", counter);
      (*config)->listens[counter].port = cfg_getint(cfg_listen, "port");
      (*config)->listens[counter].sock = -1;
    }
  memset(&(*config)->listens[counter], '\0', sizeof(struct distrend_listen));

  fprintf(stderr, "using %s as datadir\n", (*config)->datadir);

  return 0;
}
int distrend_config_free(struct distrend_config *config)
{
  options_free(config->options);
  free(config);

  return 0;
}
/* ************************** XML Functions ************************* */

// writes the general_info.xml file which is a copy of the general_info structure
// except that it doesn't hold free_clients and rendering_clients
void update_general_info(struct general_info *geninfo)
{
  xmlTextWriterPtr writer;
  char *tmp;

  writer = xmlNewTextWriterFilename(geninfo->files.geninfo, 0);
  xmlTextWriterStartDocument(writer, NULL, "utf-8", NULL);

  xmlTextWriterStartElement(writer, (xmlChar*)"general_info");

  _distren_asprintf(&tmp, "%d", geninfo->jobs_in_queue);
  xmlTextWriterWriteElement(writer, (xmlChar*)"jobs_in_queue", (xmlChar*)tmp);
  free(tmp);

  _distren_asprintf(&tmp, "%d", geninfo->total_finished_jobs);
  xmlTextWriterWriteElement(writer, (xmlChar*)"total_finished_jobs", (xmlChar*)tmp);
  free(tmp);

  _distren_asprintf(&tmp, "%d", geninfo->total_frames_rendered);
  xmlTextWriterWriteElement(writer, (xmlChar*)"total_frames_rendered", (xmlChar*)tmp);
  free(tmp);

  _distren_asprintf(&tmp, "%d", geninfo->highest_jobnum);
  xmlTextWriterWriteElement(writer, (xmlChar*)"highest_jobnum", (xmlChar*)tmp);
  free(tmp);

  xmlTextWriterEndDocument(writer);
  xmlFreeTextWriter(writer);
}

/**
   Reads general state information from general_info.xml
   into the general_info structure.
*/
int import_general_info(struct general_info *general_info)
{
  xmlDocPtr doc;
  xmlNodePtr cur;

  doc = xmlParseFile(general_info->files.geninfo);
  cur = xmlDocGetRootElement(doc);
  if (xmlStrcmp(cur->name, (xmlChar*)"general_info"))
    {
      fprintf(stderr, "xml document is wrong type");
      xmlFreeDoc(doc);
      return 1;
    }

  cur = cur->xmlChildrenNode;
  general_info->jobs_in_queue = atoi((char*)xmlNodeListGetString(doc, cur->xmlChildrenNode, 1));
  cur = cur->next;
  general_info->total_finished_jobs = atoi((char*)xmlNodeListGetString(doc, cur->xmlChildrenNode, 1));
  cur = cur->next;
  general_info->total_frames_rendered = atoi((char*)xmlNodeListGetString(doc, cur->xmlChildrenNode, 1));
  cur = cur->next;
  general_info->highest_jobnum = atoi((char*)xmlNodeListGetString(doc, cur->xmlChildrenNode, 1));

  general_info->hibernate = 0;
  general_info->free_clients = 0;
  general_info->rendering_clients = 0;
  general_info->timestamp = 0;
  general_info->total_render_power = 0;
  general_info->total_priority_pieces = 0;

  xmlFreeDoc(doc);

  return 0;
}


/**
   updates job_list.xml which lists all the jobs in the queue
   @return 0 means success
*/
// @QUERY: Likely obselete (don't remove at request of ohnobinki)
int update_xml_joblist(struct general_info *geninfo)
{
  struct distrenjob *job;
  xmlTextWriterPtr writer;
  char *tmp;
  int counter;

  /**
     update timestamp
  */
  geninfo->timestamp ++;
  if(geninfo->timestamp > 65530)
    geninfo->timestamp = 0;

  _distren_asprintf(&tmp, "%s/job_list.xml",
                    geninfo->config->datadir);
  writer = xmlNewTextWriterFilename(tmp, 0);
  free(tmp);

  xmlTextWriterStartDocument(writer, NULL, "utf-8", NULL);

  /**
     create root element job_list
  */
  xmlTextWriterStartElement(writer, (xmlChar*)"job_list");

  _distren_asprintf(&tmp, "%d", geninfo->timestamp);
  xmlTextWriterWriteAttribute(writer, (xmlChar*)"timestamp", (xmlChar*)tmp);
  free(tmp);

  geninfo->total_priority_pieces = 0;
  counter = 0;
  for(job = geninfo->head.next; job; job = job->next)
    {
      _distren_asprintf(&tmp, "%d", job->jobnum);
      xmlTextWriterWriteElement(writer, (xmlChar*)"jobnum", (xmlChar*)tmp);
      free(tmp);

      /**
        this is needed for the new frame finder to work
      
        Why the random constant numeral 11? --ohnobinki
      */
      geninfo->total_priority_pieces = geninfo->total_priority_pieces + job->priority;

      counter++;
    }

  xmlTextWriterEndElement(writer);

  /**
     close elements and end document
  */
  xmlTextWriterEndDocument(writer);

  /**
     free writer and save xml file to disk
  */
  xmlFreeTextWriter(writer);
  return 0;
}

/* ************************** Test Functions ************************* */


/** Interactive test for the queuing system */
/* @QUEUE: Test uses methods not present in C code using mysql web-based system */
int interactiveTest(int test, struct general_info *geninfo)
{
  int command;
  int32_t slaveKey = 1;
  jobnum_t jobKey = 0;
  int32_t frameNum = 0;
  int32_t newPriority = 0;
  int tmp = 0;
  struct distrend_clientset *clients;

  fprintf(stderr,"Hello!\n");

  while(test == 1)
   {
     fprintf(stderr, "Welcome to DistRen Alpha Interactive Test Mode\n\n");
     fprintf(stderr, "\t1 \tGet a frame to render\n");
     fprintf(stderr, "\t2 \tChange job priority\n");
     fprintf(stderr, "\t3 \tSet frame finished\n");
     fprintf(stderr, "\t4 \tSet frame started\n");
     fprintf(stderr, "\t5 \tStart listener\n");
     fprintf(stderr, "\t0 \tQuit\n");

     scanf("%d", &command);

     switch(command)
     {
     case 1:
       fprintf(stderr,"Slave Key: ");
       scanf("%d", &slaveKey);
       fprintf(stderr, "Got frame: ");
       if(find_jobframe(geninfo->conn, slaveKey, &jobKey, &frameNum))
         fprintf(stderr,"No frames available to render!\n");
       else if(jobKey == -1)
         fprintf(stderr,"Slave %d has no render power!", slaveKey);
       else
         fprintf(stderr, "jobKey: %d, frameNum: %d\n",jobKey,frameNum);
       break;
     case 2:
       fprintf(stderr,"Job key: ");
       scanf("%d", &tmp);
       jobKey = tmp;

       fprintf(stderr,"New priority: ");
       scanf("%d", &tmp);
       newPriority = tmp;

       change_job_priority(geninfo->conn, jobKey, newPriority);
       fprintf(stderr,"Changed!");
       break;
     case 3:
       fprintf(stderr,"Slave Key: ");
       scanf("%d", &tmp);
       slaveKey = tmp;

       fprintf(stderr,"Job Key: ");
       scanf("%d", &tmp);
       jobKey = tmp;

       fprintf(stderr,"Frame Number: ");
       scanf("%d", &tmp);
       frameNum = tmp;

       finish_frame(geninfo->conn, slaveKey, jobKey, frameNum);
       fprintf(stderr,"Finished Frame!\n");
       break;
     case 4:
       fprintf(stderr,"Slave Key: ");
       scanf("%d", &tmp);
       slaveKey = tmp;

       fprintf(stderr,"Job Key: ");
       scanf("%d", &tmp);
       jobKey = tmp;

       fprintf(stderr,"Frame Number: ");
       scanf("%d", &tmp);
       frameNum = tmp;

       start_frame(geninfo->conn, slaveKey, jobKey, frameNum);
       fprintf(stderr,"Started Frame!\n");
       break;

     case 5:
       distrend_listen(geninfo->config, &clients);
       while(1)
	 {
	   distrend_accept(geninfo->config, clients);
	   /*
	     code for reading data from clients either goes here or in distrend_accept().
	     it might make sense for us to just pass the distrend_accept() function a
	     callback which can handle packets or to have a generic packet handling
	     subsystem which gathers data into groups defined by by packet.h and then
	     passed onto the callback.
	   */
	 }
       break;
       
     case 0:
       test = 0;
       break;
     default:
       fprintf(stderr, "Invalid input, please try again.\n");
       break;
     }
   }
  return 0;
}