#include <iostream>
#include <memory>
#include <set>
#include <string>
#include <vector>

bool CmpStrEx(const std::string& expr, const std::string& str)
{
 if(expr.empty() || str.empty()) return false;

 struct State
 {
  struct Block
  {
   using pBlock=std::unique_ptr<struct Block>;
   enum Type {NOTDEF,TEXT,OPTIONAL,VARIANTS,DELIM};
   size_t b,e;
   Type type;
   const struct Block* parent;
   pBlock next,child;

   Block() = delete;
   Block(const struct Block&) = delete;
   Block(struct Block&&) = delete;

   bool isText() const {return type==TEXT;}

   Block(Type t, const struct Block* p=nullptr):b(0),e(0),type(t),parent(p),next(nullptr),child(nullptr) {}
   Block(size_t bb, size_t ee, const struct Block* p=nullptr):b(bb),e(ee),type(TEXT),parent(p),next(nullptr),child(nullptr) {}
  };

  Block::pBlock Parse(const std::string& str)
  {
   size_t e=0;
   struct Block* blk;
   struct Block* root;
   auto c=str[e];
   bool init,next;

   // First symbol
   if('['==c || '('==c) blk=new Block(('['==c)?Block::OPTIONAL:Block::VARIANTS);
   else blk=new Block(e,e+1);
   root=blk;
   init=!root->isText();
   next=!init;

   e++;
   while(e<str.length())
   {
    c=str[e];

    switch(c)
    {
     case '[':
     case '(':
     {
      (next?blk->next:blk->child).reset(new Block(('['==c)?Block::OPTIONAL:Block::VARIANTS,(next?blk->parent:blk)));
      blk=(next?blk->next:blk->child).get();
      init=true;
      next=false;
      break;
     }
     case ']':
     case ')':
     {
      blk=const_cast<struct Block*>(blk->parent);
      init=true;
      next=true;
      break;
     }
     case '|': {blk->next.reset(new Block(Block::DELIM,blk->parent)); blk=blk->next.get(); init=next=true; break;}
     default:
     {
      if(init)
      {
       (next?blk->next:blk->child).reset(new Block(e,e+1,(next?blk->parent:blk)));
       blk=(next?blk->next:blk->child).get();
      }
      else blk->e=e+1;
      init=false;
      next=true;
     }
    }
    e++;
   }
   return Block::pBlock(root);
  }

  struct Cursor
  {
   const struct Block* block;
   size_t offset;
   bool operator <(const struct Cursor& c) const {return block<c.block;}
   bool compare(const std::string& str, const char c) const {return c==str[block->b+offset];}
   Cursor(const struct Block* b, size_t o):block(b),offset(o) {}
  };

  using Cursors=std::set<struct Cursor>;
  using pCursor=std::set<struct Cursor>::const_iterator;

  Block::pBlock root;
  Cursors cursors;
  const std::string& s;

  void InitCursors(const struct Block* blk)
  {
   switch(blk->type)
   {
    case Block::TEXT: {cursors.insert({blk,0}); break;}
    case Block::OPTIONAL:
    {
     auto b=blk;
     InitCursors(b->child.get());
     while(true)
     {
      if(!b->next) break;
      b=b->next.get();
      InitCursors(b);
      if(b->type!=Block::OPTIONAL) break;
     }
     break;
    }
    case Block::VARIANTS:
    {
     auto b=blk->child.get();
     while(true)
     {
      InitCursors(b);
      while(b->type!=Block::DELIM)
      {
       if(!b->next) break;
       b=b->next.get();
      }
      if(!b->next) break;
      b=b->next.get();
     }
    }
    default: {}
   }
  }


  State(const std::string& str):root(Parse(str)),s(str) {InitCursors(root.get());}

  std::string Name() const
  {
   const struct Block* b=root.get();
   std::string res;
   while(true)
   {
    // Processing current block
    switch(b->type)
    {
     case(Block::TEXT): {res+=s.substr(b->b,b->e-b->b); break;}
     case(Block::OPTIONAL): {b=b->child.get(); goto next;}
     case(Block::VARIANTS): {b=b->child.get(); goto next;}
     case(Block::DELIM): {b=b->parent; break;}
     default: {}
    }
    // Go to next block
    while(true)
    {
     if(nullptr!=b->next) {b=b->next.get(); goto next;}
     if(nullptr!=b->parent) b=b->parent;
     else break;
    }
    if(nullptr==b->next && nullptr==b->parent) break;
    next: ;
   }
   return res;
  }


  bool CmpSmb(const char c)
  {
   pCursor p=cursors.cbegin();
   bool res=false;

   // Compare symbol with all cursors

   std::cout<<"--------------\n";
   std::cout<<"Symbol: "<<c<<"\n";

   while(p!=cursors.end())
   {
    std::cout<<p->block->b+p->offset<<" "<<s[p->block->b+p->offset]<<"\n";
    if(p->compare(s,c)) {res=true; p++;}
    else p=cursors.erase(p);
   }

   Cursors old(std::move(cursors));
   for(const auto& p:old)
   {
    auto blk=p.block;
    // Increment cursors
    if(blk->b+p.offset+1<blk->e) cursors.insert({blk,p.offset+1}); // Advance in current block
    else // Move to next block
    {
     if(!blk->next || blk->next->type==Block::DELIM) // End of chain, must go up
     {
      while(blk->parent!=nullptr)
      {
       blk=blk->parent;
       if(!blk->next || blk->next->type==Block::DELIM) continue;
       InitCursors(blk->next.get());
      }
     }
     else InitCursors(blk->next.get()); // Next block in chain
    }

    // Try to leave optional blocks
    blk=p.block;
    while(blk->parent!=nullptr)
    {
     blk=blk->parent;
     if(blk->type!=Block::OPTIONAL || !blk->next || blk->next->type==Block::DELIM) continue;
     InitCursors(blk->next.get());
    }
   }

   return res;
  }
 };


// Main function
 struct State st(expr);
 std::cout<<"Name is "<<st.Name()<<std::endl;

 // Dump code
 {
  std::cerr<<"digraph main\n{\nrankdir=TB pack=\"true\" packmode=\"node\";\n";
  std::cerr<<"node [fontsize=30, shape=rectangle, style=\"filled,rounded\", fillcolor=azure2, fixedsize=\"false\", margin=0.2, width=1, penwidth=3, fontname=\"Times New Roman\"];\n";
  std::cerr<<"edge [arrowsize=1.5, penwidth=3];\n";

  const struct State::Block* r=st.root.get();
  std::set<const struct State::Block*> visited;
  visited.insert(nullptr);
  while(true)
  {
   if(visited.count(r)==0)
   {
    std::string label;
    if(r->type==State::Block::OPTIONAL) label="[]";
    if(r->type==State::Block::VARIANTS) label="()";
    if(r->type==State::Block::DELIM) label="|";
    if(r->type==State::Block::TEXT) label=expr.substr(r->b,r->e-r->b);
    std::cerr<<"\""<<r<<"\" [label=\""<<label<<"\""<<((r->type==State::Block::TEXT)?",fontcolor=\"red\"":"")<<"];\n";
    if(r->child) std::cerr<<"\""<<r<<"\" -> \""<<r->child.get()<<"\";\n";
    if(r->next)
    {
     std::cerr<<"\""<<r<<"\" -> \""<<r->next.get()<<"\" [color=\"blue\"];\n";
     std::cerr<<"{rank=same; "<<"\""<<r<<"\"; \""<<r->next.get()<<"\";}\n";
    }
    if(r->parent!=nullptr) std::cerr<<"\""<<r<<"\" -> \""<<r->parent<<"\" [color=\"green\", penwidth=1];\n";
    visited.insert(r);
   }
   if(r->child && visited.count(r->child.get())==0) r=r->child.get();
   else if(r->next) r=r->next.get();
   else
   {
    while(r->parent!=nullptr)
    {
     r=r->parent;
     if(r->next) {r=r->next.get(); break;}
    }
   }
   if(visited.count(r)!=0 && r->parent==nullptr && visited.count(r->next.get())!=0 && visited.count(r->child.get())!=0) break;
  }
  std::cerr<<"}\n";
 }

 for(size_t pos=0; pos<str.length(); ++pos)
 {
  if(!st.CmpSmb(str[pos])) return false;
 }

 return true;
}


int main(int argc, char** argv)
{
 if(argc!=3) return 1;
 std::cout<<"Compare "<<argv[1]<<" with template "<<argv[2]<<": "<<(CmpStrEx(argv[2],argv[1])?"match":"not match")<<std::endl;
 return 0;
}