#include "ast.hpp"
#include <iostream>

LLVMContext TheContext;
map<string, Value*> NamedValues;
IRBuilder<> Builder(TheContext);
Module* TheModule;
FunctionPassManager *TheFPM;

ExprAST::~ExprAST() {

}

InnerExprAST::InnerExprAST(ExprAST* a) {
  _nodes.resize(0);
  _nodes.push_back(a);
}

InnerExprAST::InnerExprAST(ExprAST* a, ExprAST* b) {
  _nodes.resize(0);
  _nodes.push_back(a);
  _nodes.push_back(b);
}

InnerExprAST::InnerExprAST(ExprAST* a, ExprAST* b, ExprAST* c) {
  _nodes.resize(0);
  _nodes.push_back(a);
  _nodes.push_back(b);
  _nodes.push_back(c);
}

InnerExprAST::InnerExprAST(ExprAST* a, ExprAST* b, ExprAST* c, ExprAST* d) {
  _nodes.resize(0);
  _nodes.push_back(a);
  _nodes.push_back(b);
  _nodes.push_back(c);
  _nodes.push_back(d);
}

InnerExprAST::InnerExprAST(vector<ExprAST*> a) {
  _nodes = a;
}

InnerExprAST::~InnerExprAST() {
  for (unsigned i = 0; i < _nodes.size(); i++)
    delete _nodes[i];
}

FunctionAST::~FunctionAST() {
  delete Body;
}

Value* NumberExprAST::codegen() const {
  return ConstantFP::get(TheContext, APFloat(Val));
}

Value* VariableExprAST::codegen() const {
  Value* tmp = NamedValues[Name];
  if (tmp == NULL) {
    cerr << "Promenljiva " << Name << " nije prethodno definisana" << endl;
    return NULL;
  }
  return tmp;
}

Value* AddExprAST::codegen() const {
  Value* l = _nodes[0]->codegen();
  Value* d = _nodes[1]->codegen();
  if (l == NULL || d == NULL) {
    return NULL;
  }
  return Builder.CreateFAdd(l, d, "addtmp");
}

Value* SubExprAST::codegen() const {
  Value* l = _nodes[0]->codegen();
  Value* d = _nodes[1]->codegen();
  if (l == NULL || d == NULL) {
    return NULL;
  }
  return Builder.CreateFSub(l, d, "subtmp");

}

Value* MulExprAST::codegen() const {
  Value* l = _nodes[0]->codegen();
  Value* d = _nodes[1]->codegen();
  if (l == NULL || d == NULL) {
    return NULL;
  }
  return Builder.CreateFMul(l, d, "multmp");
}

Value* DivExprAST::codegen() const {
  Value* l = _nodes[0]->codegen();
  Value* d = _nodes[1]->codegen();
  if (l == NULL || d == NULL) {
    return NULL;
  }
  return Builder.CreateFDiv(l, d, "divtmp");
}

Value* LtExprAST::codegen() const {
  Value* l = _nodes[0]->codegen();
  Value* d = _nodes[1]->codegen();
  if (l == NULL || d == NULL) {
    return NULL;
  }
  l = Builder.CreateFCmpULT(l, d, "lttmp");
  return Builder.CreateUIToFP(l, Type::getDoubleTy(TheContext), "booltmp");
}

Value* GtExprAST::codegen() const {
  Value* l = _nodes[0]->codegen();
  Value* d = _nodes[1]->codegen();
  if (l == NULL || d == NULL) {
    return NULL;
  }
  l = Builder.CreateFCmpUGT(l, d, "gttmp");
  return Builder.CreateUIToFP(l, Type::getDoubleTy(TheContext), "booltmp");
}

Value* SeqExprAST::codegen() const {
  Value* l = _nodes[0]->codegen();
  Value* d = _nodes[1]->codegen();
  if (l == NULL || d == NULL) {
    return NULL;
  }
  return d;
}


Value* CallExprAST::codegen() const {
  // Look up the name in the global module table.
  Function *CalleeF = TheModule->getFunction(Callee);
  if (!CalleeF) {
    cerr << "Poziv fje " << Callee << " koja nije definisana" << endl;
    return NULL;
  }
  
  // If argument mismatch error.
  if (CalleeF->arg_size() != _nodes.size()) {
    cerr << "Pogresan broj argumenata fje " << Callee << endl;
    return NULL;
  }
  
  vector<Value *> ArgsV;
  for (unsigned i = 0, e = _nodes.size(); i != e; ++i) {
    ArgsV.push_back(_nodes[i]->codegen());
    if (!ArgsV.back())
      return NULL;
  }
  
  return Builder.CreateCall(CalleeF, ArgsV, "calltmp");
}

Value* IfExprAST::codegen() const {
  Value *CondV = _nodes[0]->codegen();
  if (CondV == NULL)
    return NULL;

  CondV = Builder.CreateFCmpONE(CondV, ConstantFP::get(TheContext, APFloat(0.0)), "ifcond");

  Function *TheFunction = Builder.GetInsertBlock()->getParent();
  BasicBlock *ThenBB = BasicBlock::Create(TheContext, "then", TheFunction);
  BasicBlock *ElseBB = BasicBlock::Create(TheContext, "else");
  BasicBlock *MergeBB = BasicBlock::Create(TheContext, "ifcont");
  
  Builder.CreateCondBr(CondV, ThenBB, ElseBB);

  Builder.SetInsertPoint(ThenBB);
  Value *Then = _nodes[1]->codegen();
  if (Then == NULL)
    return NULL;
  Builder.CreateBr(MergeBB);
  ThenBB = Builder.GetInsertBlock();

  TheFunction->getBasicBlockList().push_back(ElseBB);
  Builder.SetInsertPoint(ElseBB);
  Value *Else = _nodes[2]->codegen();
  if (Else == NULL)
    return NULL;
  Builder.CreateBr(MergeBB);
  ElseBB = Builder.GetInsertBlock();

  TheFunction->getBasicBlockList().push_back(MergeBB);
  Builder.SetInsertPoint(MergeBB);
  PHINode *PN = Builder.CreatePHI(Type::getDoubleTy(TheContext), 2, "iftmp");
  PN->addIncoming(Then, ThenBB);
  PN->addIncoming(Else, ElseBB);
  return PN;
}

Value* ForExprAST::codegen() const {
  Value* StartVal = _nodes[0]->codegen();
  if (StartVal == NULL)
    return NULL;
  
  Function* TheFunction = Builder.GetInsertBlock()->getParent();
  BasicBlock* LoopBB = BasicBlock::Create(TheContext, "loop", TheFunction);
  Builder.CreateBr(LoopBB);
  BasicBlock* EntryBB = Builder.GetInsertBlock();

  Builder.SetInsertPoint(LoopBB);
  PHINode* Variable = Builder.CreatePHI(Type::getDoubleTy(TheContext), 2, VarName);
  Variable->addIncoming(StartVal, EntryBB);
  
  Value* OldVal = NamedValues[VarName];
  NamedValues[VarName] = Variable;


  Value* Body = _nodes[3]->codegen();
  if (Body == NULL)
    return NULL;

  Value* StepVal = NULL;
  if (_nodes[2] != NULL)
    StepVal = _nodes[2]->codegen();
  else
    StepVal = ConstantFP::get(TheContext, APFloat(1.0));
  if (StepVal == NULL)
    return NULL;
  Value *NextVar = Builder.CreateFAdd(Variable, StepVal, "nextvar");
  BasicBlock* EndLoopBB = Builder.GetInsertBlock();
  Variable->addIncoming(NextVar, EndLoopBB);

  Value *CondVal = _nodes[1]->codegen();
  if (CondVal == NULL)
    return NULL;
  CondVal = Builder.CreateFCmpONE(CondVal, ConstantFP::get(TheContext, APFloat(0.0)), "loopcond");

  BasicBlock* AfterLoopBB = BasicBlock::Create(TheContext, "afterloop", TheFunction);
  Builder.CreateCondBr(CondVal, LoopBB, AfterLoopBB);

  Builder.SetInsertPoint(AfterLoopBB);

  if (OldVal != NULL)
    NamedValues[VarName] = OldVal;
  else
    NamedValues.erase(VarName);
  
  return ConstantFP::get(TheContext, APFloat(0.0));
}

Value* VarExprAST::codegen() const {
  vector<Value*> OldValues;
  for (unsigned i = 0; i < V.size(); i++) {
    Value* Tmp = NULL;
    if (V[i].second != NULL)
      Tmp = V[i].second->codegen();
    else
      Tmp = ConstantFP::get(TheContext, APFloat(0.0));
    if (Tmp == NULL)
      return NULL;
    OldValues.push_back(NamedValues[V[i].first]);
    NamedValues[V[i].first] = Tmp;
  }

  Value *Body = _nodes[0]->codegen();
  if (Body == NULL)
    return NULL;

  for (unsigned i = 0; i < V.size(); i++)
    if (OldValues[i] != NULL)
      NamedValues[V[i].first] = OldValues[i];
    else
      NamedValues.erase(V[i].first);
  
  return Body;
}

VarExprAST::~VarExprAST() {
  for (unsigned i = 0; i < V.size(); i++)
    delete V[i].second;
}

Function* PrototypeAST::codegen() const {
  vector<Type*> Doubles(Args.size(),
			Type::getDoubleTy(TheContext));
  FunctionType *FT =
    FunctionType::get(Type::getDoubleTy(TheContext), Doubles, false);
  
  Function *F =
    Function::Create(FT, Function::ExternalLinkage, Name, TheModule);
  
  unsigned Idx = 0;
  for (auto &Arg : F->args())
    Arg.setName(Args[Idx++]);
  
  return F;
}

Function* FunctionAST::codegen() const {
  // First, check for an existing function from a previous 'extern' declaration.
  Function *TheFunction = TheModule->getFunction(Proto.getName());
  
  if (!TheFunction)
    TheFunction = Proto.codegen();
  
  if (!TheFunction)
    return NULL;
  
  if (!TheFunction->empty()) {
    cerr << "Nije dozvoljena redefinicija fje " << Proto.getName() << endl;
    return NULL;
  }
  
  // Create a new basic block to start insertion into.
  BasicBlock *BB = BasicBlock::Create(TheContext, "entry", TheFunction);
  Builder.SetInsertPoint(BB);
  
  // Record the function arguments in the NamedValues map.
  NamedValues.clear();
  for (auto &Arg : TheFunction->args())
    NamedValues[Arg.getName()] = &Arg;
  
  if (Value *RetVal = Body->codegen()) {
    // Finish off the function.
    Builder.CreateRet(RetVal);
    
    // Validate the generated code, checking for consistency.
    verifyFunction(*TheFunction);

    TheFPM->run(*TheFunction);
    
    return TheFunction;
  }
  
  // Error reading body, remove function.
  TheFunction->eraseFromParent();
  return NULL;
}

void InitializeModuleAndPassManager() {
  TheModule = new Module("my_module", TheContext);

  TheFPM = new FunctionPassManager(TheModule);

  // Eliminate Common SubExpressions.
  TheFPM->add(createGVNPass());

  TheFPM->doInitialization();
}