/// \file stream.cpp
/// Utilities for handling streams.

#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
#include <stdlib.h>
#include <semaphore.h>
#include "json.h"
#include "stream.h"
#include "procs.h"
#include "config.h"
#include "socket.h"
#include "defines.h"
#include "shared_memory.h"
#include "dtsc.h"

std::string Util::getTmpFolder() {
  std::string dir;
  char * tmp_char = 0;
  if (!tmp_char) {
    tmp_char = getenv("TMP");
  }
  if (!tmp_char) {
    tmp_char = getenv("TEMP");
  }
  if (!tmp_char) {
    tmp_char = getenv("TMPDIR");
  }
  if (tmp_char) {
    dir = tmp_char;
    dir += "/mist";
  } else {
#if defined(_WIN32) || defined(_CYGWIN_)
    dir = "C:/tmp/mist";
#else
    dir = "/tmp/mist";
#endif
  }
  if (access(dir.c_str(), 0) != 0) {
    mkdir(dir.c_str(), S_IRWXU | S_IRWXG | S_IRWXO); //attempt to create mist folder - ignore failures
  }
  return dir + "/";
}

/// Filters the streamname, removing invalid characters and converting all
/// letters to lowercase. If a '?' character is found, everything following
/// that character is deleted. The original string is modified. If a '+'
/// exists, then only the part before the + is sanitized.
void Util::sanitizeName(std::string & streamname) {
  //strip anything that isn't numbers, digits or underscores
  size_t index = streamname.find('+');
  if(index != std::string::npos){
    std::string preplus = streamname.substr(0,index);
    sanitizeName(preplus);
    streamname = preplus +"+"+streamname.substr(index+1);
    return;
  }
  for (std::string::iterator i = streamname.end() - 1; i >= streamname.begin(); --i) {
    if (*i == '?') {
      streamname.erase(i, streamname.end());
      break;
    }
    if ( !isalpha( *i) && !isdigit( *i) && *i != '_' && *i != '+' && *i != '.'){
      streamname.erase(i);
    } else {
      *i = tolower(*i);
    }
  }
}

/// Starts a process for a VoD stream.
bool Util::startInput(std::string streamname, std::string filename, bool forkFirst) {
  if (streamname.size() > 100){
    FAIL_MSG("Stream opening denied: %s is longer than 100 characters (%lu).", streamname.c_str(), streamname.size());
    return false;
  }
  IPC::sharedPage mistConfOut("!mistConfig", DEFAULT_CONF_PAGE_SIZE);
  IPC::semaphore configLock("!mistConfLock", O_CREAT | O_RDWR, ACCESSPERMS, 1);
  configLock.wait();
  DTSC::Scan config = DTSC::Scan(mistConfOut.mapped, mistConfOut.len);
  
  sanitizeName(streamname);
  std::string smp = streamname.substr(0, streamname.find('+'));
  //check if smp (everything before +) exists
  DTSC::Scan stream_cfg = config.getMember("streams").getMember(smp);
  if (!stream_cfg){
    DEBUG_MSG(DLVL_MEDIUM, "Stream %s not configured", streamname.c_str());
    configLock.post();//unlock the config semaphore
    return false;
  }
  
  //If starting without filename parameter, check if the stream is already active.
  //If yes, don't activate again to prevent duplicate inputs.
  //It's still possible a duplicate starts anyway, this is caught in the inputs initializer.
  //Note: this uses the _whole_ stream name, including + (if any).
  //This means "test+a" and "test+b" have separate locks and do not interact with each other.
  if (!filename.size()){
    IPC::semaphore playerLock(std::string("/lock_" + streamname).c_str(), O_CREAT | O_RDWR, ACCESSPERMS, 1);
    if (!playerLock.tryWait()) {
      playerLock.close();
      DEBUG_MSG(DLVL_MEDIUM, "Stream %s already active - not activating again", streamname.c_str());
      configLock.post();//unlock the config semaphore
      return true;
    }
    playerLock.post();
    playerLock.close();
    filename = stream_cfg.getMember("source").asString();
  }
  
  
  std::string player_bin;
  bool selected = false;
  long long int curPrio = -1;
  //check in curConf for capabilities-inputs-<naam>-priority/source_match
  DTSC::Scan inputs = config.getMember("capabilities").getMember("inputs");
  DTSC::Scan input;
  unsigned int input_size = inputs.getSize();
  for (unsigned int i = 0; i < input_size; ++i){
    input = inputs.getIndice(i);
    
    //if match voor current stream && priority is hoger dan wat we al hebben
    if (curPrio < input.getMember("priority").asInt()){
      std::string source = input.getMember("source_match").asString();
      std::string front = source.substr(0,source.find('*'));
      std::string back = source.substr(source.find('*')+1);
      DEBUG_MSG(DLVL_MEDIUM, "Checking input %s: %s (%s)", inputs.getIndiceName(i).c_str(), input.getMember("name").asString().c_str(), source.c_str());
      
      if (filename.substr(0,front.size()) == front && filename.substr(filename.size()-back.size()) == back){
        player_bin = Util::getMyPath() + "MistIn" + input.getMember("name").asString();
        curPrio = input.getMember("priority").asInt();
        selected = true;
      }
    }
  }
  
  if (!selected){
    configLock.post();//unlock the config semaphore
    FAIL_MSG("No compatible input found for stream %s: %s", streamname.c_str(), filename.c_str());
    return false;
  }

  //copy the neccessary arguments to separate storage so we can unlock the config semaphore safely
  std::map<std::string, std::string> str_args;
  //check required parameters
  DTSC::Scan required = input.getMember("required");
  unsigned int req_size = required.getSize();
  for (unsigned int i = 0; i < req_size; ++i){
    std::string opt = required.getIndiceName(i);
    if (!stream_cfg.getMember(opt)){
      configLock.post();//unlock the config semaphore
      FAIL_MSG("Required parameter %s for stream %s missing", opt.c_str(), streamname.c_str());
      return false;
    }
    str_args[required.getIndice(i).getMember("option").asString()] = stream_cfg.getMember(opt).asString();
  }
  //check optional parameters
  DTSC::Scan optional = input.getMember("optional");
  unsigned int opt_size = optional.getSize();
  for (unsigned int i = 0; i < opt_size; ++i){
    std::string opt = optional.getIndiceName(i);
    DEBUG_MSG(DLVL_VERYHIGH, "Checking optional %u: %s", i, opt.c_str());
    if (stream_cfg.getMember(opt)){
      str_args[optional.getIndice(i).getMember("option").asString()] = stream_cfg.getMember(opt).asString();
    }
  }
  
  //finally, unlock the config semaphore
  configLock.post();

  DEBUG_MSG(DLVL_MEDIUM, "Starting %s -s %s %s", player_bin.c_str(), streamname.c_str(), filename.c_str());
  char * argv[30] = {(char *)player_bin.c_str(), (char *)"-s", (char *)streamname.c_str(), (char *)filename.c_str()};
  int argNum = 3;
  std::string debugLvl;
  if (Util::Config::printDebugLevel != DEBUG && !str_args.count("--debug")){
    debugLvl = JSON::Value((long long)Util::Config::printDebugLevel).asString();
    argv[++argNum] = (char *)"--debug";
    argv[++argNum] = (char *)debugLvl.c_str();
  }
  for (std::map<std::string, std::string>::iterator it = str_args.begin(); it != str_args.end(); ++it){
    argv[++argNum] = (char *)it->first.c_str();
    argv[++argNum] = (char *)it->second.c_str();
  }
  argv[++argNum] = (char *)0;
  
  int pid = 0;
  if (forkFirst){
    DEBUG_MSG(DLVL_DONTEVEN, "Forking");
    pid = fork();
    if (pid == -1) {
      FAIL_MSG("Forking process for stream %s failed: %s", streamname.c_str(), strerror(errno));
      return false;
    }
  }else{
    DEBUG_MSG(DLVL_DONTEVEN, "Not forking");
  }
  
  if (pid == 0){
    DEBUG_MSG(DLVL_DONTEVEN, "execvp");
    execvp(argv[0], argv);
    FAIL_MSG("Starting process %s for stream %s failed: %s", argv[0], streamname.c_str(), strerror(errno));
    _exit(42);
  }
  return true;
}