#include <stack>
#include "deptree.h"

int DepTree::CreateNodeFromVar(const std::string& var, DepTreeVars& vars, CallStack& callstack)
{
 COUT(DEBUG)<<"DepTree::CreateNodeFromVar "<<var<<std::endl;
 if(G_vars.count(var)==0)
 {
  COUT(ERROR)<<"Definition of variable "<<var<<" not found"<<std::endl;
  return 1;
 }

 UsedType ids;

 vars[var]=this;
 G_vars[var]->UsedIdents(ids);
 type=DepTree::VAR;
 name=var;

 DepTreeVars::const_iterator d;
 int ret;
 callstack.insert(this);
 for(auto& i:ids)
 {
  d=vars.find(i);
  if(d==vars.end())
  {
   auto n=*childrens.insert(new DepTree).first;
   n->parents.insert(this);
   ret=n->CreateNodeFromVar(i,vars,callstack);
   if(ret!=0)
   {
    COUT(ERROR)<<" in definition of variable "<<name<<std::endl;
    return ret;
   }
  }
  else
  {
   if(callstack.find(d->second)!=callstack.end())
   {
    COUT(ERROR)<<"Circular dependency of variable "<<name<<" from variable "<<i<<std::endl;
    return 1;
   }
   childrens.insert(d->second);
   d->second->parents.insert(this);
  }
 }
 callstack.erase(this);

 return 0;
}


int DepTree::CreateNodeFromSP(DepTree::NodeType list, G_toType::size_type ind, DepTreeVars& vars)
{
 if(list!=DepTree::SAVE && list!=DepTree::PRINT)
 {
  COUT(ERROR)<<"Internal error, incorrect NodeType in DepTree::CreateNodeFromSP()."<<std::endl;
  return 2;
 }
 COUT(DEBUG)<<"DepTree::CreateNodeFromSP "<<((list==DepTree::SAVE)?G_tosave:G_toprint)[ind]->Dump()<<std::endl;

 std::set<std::string> ids;
 CallStack callstack;

 type=list;
 index=ind;

 if(type==DepTree::SAVE) G_tosave[index]->UsedIdents(ids);
 else if(type==DepTree::PRINT) G_toprint[index]->UsedIdents(ids);
 DepTreeVars::const_iterator d;
 int ret;
 for(auto& i:ids)
 {
  d=vars.find(i);
  if(d==vars.end())
  {
   auto n=*childrens.insert(new DepTree).first;
   n->parents.insert(this);
   ret=n->CreateNodeFromVar(i,vars,callstack);
   if(ret!=0)
   {
    COUT(ERROR)<<" in "<<((type==DepTree::SAVE)?"save":"print")<<" directive "<<((type==DepTree::SAVE)?G_tosave:G_toprint)[index]->Dump()<<"."<<std::endl;
    return ret;
   }
  }
  else
  {
   childrens.insert(d->second);
   d->second->parents.insert(this);
  }
 }

 return 0;
}


int DepTree::CreateGlobalTree(UsedType& used)
{
 if(parents.size()!=0)
 {
  COUT(ERROR)<<"Internal error, DepTree::CreateGlobalTree() call for non-root node."<<std::endl;
  return 2;
 }

 DepTreeVars vars;

 type=DepTree::ROOT;
 for(G_toType::size_type i=0; i<G_tosave.size(); i++)
 {
  auto n=*childrens.insert(new DepTree).first;
  n->parents.insert(this);
  auto ret=n->CreateNodeFromSP(DepTree::SAVE,i,vars);
  if(ret!=0) return ret;
 }
 for(G_toType::size_type i=0; i<G_toprint.size(); i++)
 {
  auto n=*childrens.insert(new DepTree).first;
  n->parents.insert(this);
  auto ret=n->CreateNodeFromSP(DepTree::PRINT,i,vars);
  if(ret!=0) return ret;
 }

 for(auto& i: vars) used.insert(i.first);

 return 0;
}


DepTree::LeafVector DepTree::FindLeafNodes() const
{
 LeafVector leafs;
 std::stack<NodeVector::const_iterator> path,ends;
 NodeVector::const_iterator it,end;
 // define isvisited as reversion of last visited
 bool isvisited=!visited;
 // ascending to root
 const DepTree* root=this;
 while(root->parents.size()!=0) root=*(root->parents.begin());

 const DepTree* curnode=root;
 curnode->visited=isvisited;
 it=curnode->childrens.begin();
 end=curnode->childrens.end();

 while(true)
 {
  if(it!=end)
  {
   if((*it)->visited==isvisited) {++it; continue;}
   path.push(it); ends.push(end);
   curnode=(*it);
   curnode->visited=isvisited;
   it=curnode->childrens.begin();
   end=curnode->childrens.end();
   if(it==end) leafs.push_back(const_cast<DepTree*>(curnode));
  }
  else
  {
   if(path.size()==0) break;
   it=path.top(); path.pop();
   end=ends.top(); ends.pop();
   ++it;
  }
 }

 return leafs;
}


// Multi-threaded version
void* TreeEvaluateM(void* arg)
{
 struct timespec skip={0,10000000};
 DepTree::thread_params* p=reinterpret_cast<DepTree::thread_params*>(arg);
 DepTree* leaf;
 ObjectBase *ob,*eob;
 ObjectList* ol;
 bool err;

 while(true)
 {
  // Begin critical section (access to root)
  pthread_mutex_lock(&p->root_mtx);
  // Check, if all done, or error happens?
  if(0==p->root->childrens.size() || 0!=p->exitcode) {pthread_mutex_unlock(&p->root_mtx); return 0;}
  // End critical section
  pthread_mutex_unlock(&p->root_mtx);

  // Begin critical section (access to leafs)
  pthread_mutex_lock(&p->leaf_mtx);
  // Check, if some work available?
  if(0==p->leafs.size()) {pthread_mutex_unlock(&p->leaf_mtx); nanosleep(&skip,0); continue;}
  // Select working node
  leaf=*(p->leafs.begin());
  // and remove its from list
  p->leafs.erase(p->leafs.begin());
  // End critical section
  pthread_mutex_unlock(&p->leaf_mtx);

  if(DepTree::SAVE==leaf->type)
  {
   err=false;

   // Begin critical section (access to G_toprint or G_tosave)
   pthread_mutex_lock(&p->prsv_mtx);
   ol=G_tosave[leaf->index];
   // End critical section
   pthread_mutex_unlock(&p->prsv_mtx);

   ol->Evaluate(&err); // For list Evaluate always return 0;
   if(err)
   {
    COUT(ERROR)<<" in instruction save"<<ol->Dump()<<")"<<std::endl;
    p->exitcode=1;
    return 0;
   }
   if(!Save(ol))
   {
    p->exitcode=1;
    return 0;
   }
   // This leaf can have only one parent - root
   // Begin critical section (access to root)
   pthread_mutex_lock(&p->root_mtx);
   (*leaf->parents.begin())->childrens.erase(leaf);
   // End critical section
   pthread_mutex_unlock(&p->root_mtx);
  }

  if(DepTree::PRINT==leaf->type)
  {
   err=false;

   // Begin critical section (access to G_toprint or G_tosave)
   pthread_mutex_lock(&p->prsv_mtx);
   ol=G_toprint[leaf->index];
   // End critical section
   pthread_mutex_unlock(&p->prsv_mtx);

   ol->Evaluate(&err); // For list Evaluate always return 0;
   if(err)
   {
    COUT(ERROR)<<" in instruction print"<<ol->Dump()<<")"<<std::endl;
    p->exitcode=1;
    return 0;
   }
   if(!Print(ol))
   {
    p->exitcode=1;
    return 0;
   }

   // Begin critical section (access to root)
   pthread_mutex_lock(&p->root_mtx);
   // This leaf can have only one parent - root
   (*leaf->parents.begin())->childrens.erase(leaf);
   // End critical section
   pthread_mutex_unlock(&p->root_mtx);

  }

  if(DepTree::VAR==leaf->type)
  {
   // Begin critical section (access to G_vars)
   pthread_mutex_lock(&p->vars_mtx);
   ob=G_vars.at(leaf->name);
   G_vars.erase(leaf->name);
   // End critical section
   pthread_mutex_unlock(&p->vars_mtx);

   // Main working call
   err=false;
   eob=ob->Evaluate(&err);
   if(err)
   {
    COUT(ERROR)<<" in definition of variable "<<leaf->name<<std::endl;
    p->exitcode=1;
    return 0;
   }

   // eob is evaluated object
   if(0!=eob) delete ob;
   else eob=ob;

   // Begin critical section (access to tree structure)
   pthread_mutex_lock(&p->tree_mtx);
   for(auto& i:leaf->parents)
   {
    // leaf not children of anyone
    i->childrens.erase(leaf);
    // Replace variable on eob
    if(DepTree::SAVE==i->type)
    {
     // Begin critical section (access to G_toprint or G_tosave)
     pthread_mutex_lock(&p->prsv_mtx);
     G_tosave[i->index]->ReplaceVar(leaf->name,eob);    // ReplaceVar always return 0 for ObjectList
     // End critical section
     pthread_mutex_unlock(&p->prsv_mtx);
    }
    if(DepTree::PRINT==i->type)
    {
     // Begin critical section (access to G_toprint or G_tosave)
     pthread_mutex_lock(&p->prsv_mtx);
     G_toprint[i->index]->ReplaceVar(leaf->name,eob);   // ReplaceVar always return 0 for ObjectList
     // End critical section
     pthread_mutex_unlock(&p->prsv_mtx);
    }
    if(DepTree::VAR==i->type)
    {
     // Begin critical section (access to G_vars)
     pthread_mutex_lock(&p->vars_mtx);
     ob=G_vars[i->name]->ReplaceVar(leaf->name,eob);
     if(0!=ob)
     {
      delete G_vars[i->name];
      G_vars[i->name]=ob;
     }
     // End critical section
     pthread_mutex_unlock(&p->vars_mtx);
    }

    // Begin critical section (access to leafs)
    pthread_mutex_lock(&p->leaf_mtx);
    // If node have no children, it's a new leaf node
    if(0==i->childrens.size() && DepTree::ROOT!=i->type) p->leafs.push_back(i);
    pthread_mutex_unlock(&p->leaf_mtx);
    // End critical section
   }
   // End critical section
   pthread_mutex_unlock(&p->tree_mtx);
   delete eob;
  }

  leaf->parents.clear();
  delete leaf;
 }
 return 0;
}


// Single-threaded version
void* TreeEvaluate(void* arg)
{
 DepTree::thread_params* p=reinterpret_cast<DepTree::thread_params*>(arg);
 DepTree* leaf;
 ObjectBase *ob,*eob;
 ObjectList* ol;
 bool err;
 while(0!=p->leafs.size())
 {
  // Select working node
  leaf=*(p->leafs.begin());
  // and remove its from list
  p->leafs.erase(p->leafs.begin());

  if(DepTree::SAVE==leaf->type)
  {
   err=false;
   ol=G_tosave[leaf->index];
   ol->Evaluate(&err); // For list Evaluate always return 0;
   if(err)
   {
    COUT(ERROR)<<" in instruction save"<<ol->Dump()<<")"<<std::endl;
    p->exitcode=1;
    return 0;
   }
   // eob is evaluated object
   if(!Save(ol))
   {
    p->exitcode=1;
    return 0;
   }
   // This leaf can have only one parent - root
   (*leaf->parents.begin())->childrens.erase(leaf);
  }

  if(DepTree::PRINT==leaf->type)
  {
   err=false;
   ol=G_toprint[leaf->index];
   ol->Evaluate(&err); // For list Evaluate always return 0;
   if(err)
   {
    COUT(ERROR)<<" in instruction print"<<ol->Dump()<<")"<<std::endl;
    p->exitcode=1;
    return 0;
   }
   if(!Print(ol))
   {
    p->exitcode=1;
    return 0;
   }
   // This leaf can have only one parent - root
   (*leaf->parents.begin())->childrens.erase(leaf);
  }

  if(DepTree::VAR==leaf->type)
  {
   err=false;
   ob=G_vars.at(leaf->name);
   G_vars.erase(leaf->name);
   // Main working call
   eob=ob->Evaluate(&err);
   if(err)
   {
    COUT(ERROR)<<" in definition of variable "<<leaf->name<<std::endl;
    p->exitcode=1;
    return 0;
   }

   // eob is evaluated object
   if(0!=eob) delete ob;
   else eob=ob;
   //G_vars.erase(leaf->name);
   for(auto& i:leaf->parents)
   {
    // leaf not children of anyone
    i->childrens.erase(leaf);
    // Replace variable on eob
    if(DepTree::SAVE==i->type) G_tosave[i->index]->ReplaceVar(leaf->name,eob);   // ReplaceVar always return 0 for ObjectList
    if(DepTree::PRINT==i->type) G_toprint[i->index]->ReplaceVar(leaf->name,eob);
    if(DepTree::VAR==i->type)
    {
     ob=G_vars[i->name]->ReplaceVar(leaf->name,eob);
     if(0!=ob) {delete G_vars[i->name]; G_vars[i->name]=ob;}
    }
    // If node have no children, it's a new leaf node
    if(0==i->childrens.size() && DepTree::ROOT!=i->type) p->leafs.push_back(i);
   }
   delete eob;
  }
  leaf->parents.clear();
  delete leaf;
 }
 return 0;
}


int DepTree::EvaluateTree(unsigned int nthreads)
{
 DepTree::thread_params p;

 p.exitcode=0;
 p.leafs=FindLeafNodes();

 if(1==nthreads) TreeEvaluate(&p);
 else
 {
  pthread_t* threads=new pthread_t[nthreads-1];
  p.root=this;
  pthread_mutex_init(&p.leaf_mtx,0);
  pthread_mutex_init(&p.root_mtx,0);
  pthread_mutex_init(&p.vars_mtx,0);
  pthread_mutex_init(&p.prsv_mtx,0);
  pthread_mutex_init(&p.tree_mtx,0);
  while(0!=p.root->parents.size()) p.root=*(p.root->parents.begin());

  for(unsigned int i=0;i<nthreads-1;++i) pthread_create(threads+i,0,&TreeEvaluateM,&p);
  TreeEvaluateM(&p);
  for(unsigned int i=0;i<nthreads-1;++i) pthread_join(threads[i],0);
  delete[] threads;
  pthread_mutex_destroy(&p.leaf_mtx);
  pthread_mutex_destroy(&p.root_mtx);
  pthread_mutex_destroy(&p.vars_mtx);
  pthread_mutex_destroy(&p.prsv_mtx);
  pthread_mutex_destroy(&p.tree_mtx);
 }
 return p.exitcode;
}