package mycompiler.mystatement;

import java.util.Hashtable;
import java.util.Vector;

import typinferenz.JavaCodeResult;
import typinferenz.SingleConstraint;
import typinferenz.ConstraintsSet;
import typinferenz.FreshTypeVariable;
import typinferenz.FunN;
import typinferenz.ResultSet;
import typinferenz.Typable;
import typinferenz.TypinferenzException;
import typinferenz.assumptions.TypeAssumptions;
import mycompiler.mybytecode.ClassFile;
import mycompiler.mybytecode.CodeAttribute;
import mycompiler.myclass.Class;
import mycompiler.myclass.FormalParameter;
import mycompiler.myclass.Method;
import mycompiler.myclass.ParameterList;
import mycompiler.myexception.CTypeReconstructionException;
import mycompiler.myexception.JVMCodeException;
import mycompiler.myexception.SCStatementException;
import mycompiler.mytype.DoubleType;
import mycompiler.mytype.GenericTypeVar;
import mycompiler.mytype.Type;
import mycompiler.mytype.TypePlaceholder;
import mycompiler.mytypereconstruction.CSupportData;
import mycompiler.mytypereconstruction.CTriple;
import mycompiler.mytypereconstruction.set.CSubstitutionSet;
import mycompiler.mytypereconstruction.set.CTripleSet;
import mycompiler.mytypereconstruction.set.CTypeAssumptionSet;
import mycompiler.mytypereconstruction.typeassumption.CParaTypeAssumption;
import mycompiler.mytypereconstruction.typeassumption.CTypeAssumption;

/**
 * @author A10023 - Andreas Stadelmeier
 * Momentan erweitert LambdaExpression noch Expr und erbt dadurch auch von ExprStatement ist also auch ein Statement
 * 
 * LambdaExpression Aufbau:
 * ( ParameterList ) -> { method_body };
 */
public class LambdaExpression extends Expr{ 
	
	private Block method_body;
	private ParameterList params;
	
	public LambdaExpression(int offset, int variableLength) {
		super(offset, variableLength);
		setParameterList(new ParameterList());//default is empty parameterlist
	}
	
	public void setBody(Block block){
		method_body = block;
	}
	
	public void setExpr(Expr expression){
		Block bl = new Block();
		Return returnStmt = new Return(0, 0);
		returnStmt.retexpr = expression;
		bl.set_Statement(returnStmt);
		this.setBody(bl);
	}
	
	public void setParameterList(ParameterList params){
		this.params = params;
	}


	@Override
	public void codegen(ClassFile classfile, CodeAttribute code, Vector paralist)
			throws JVMCodeException {
		// TODO Auto-generated method stub
		
	}


	@Override
	public void wandleRefTypeAttributes2GenericAttributes(
			Vector<Type> paralist,
			Vector<GenericTypeVar> genericMethodParameters) {
		// TODO Auto-generated method stub
		
	}

	@Override
	public boolean addOffsetsToStatement(CTypeAssumption localAssumption,
			String NameVariable, boolean isMemberVariable) {
		// TODO Auto-generated method stub
		return false;
	}

	@Override
	public String get_Name() {
		// TODO Auto-generated method stub
		return null;
	}


	@Override
	public void addOffsetsToExpression(CTypeAssumption localAssumption,
			String NameVariable, boolean isMemberVariable) {
		// TODO Auto-generated method stub
		
	}

	
	/**
	  * Spezifikation:
	  * 
	  * TYPEExpr( Ass, Lambda( (x1 , . . . , xN ), expr|stmt ) ) =
	  * let
	  * AssArgs = { xi : ai | ai fresh type variables }
	  * (exprt : rty, ConS) = TYPEExpr( Ass ∪ AssArgs, expr )
	  * | (stmtt : rty, ConS) = TYPEStmt( Ass u AssArgs, stmt )
	  * in
	  * (Lambda( (x1 : a1 , . . . , xN : aN ), exprt : rty|stmtt : rty ) : a,
	  * ConS ∪ { (FunN<rty, a1 , . . . , aN > a) }),
	  * where a is a fresh type variable 
	 */
	@Override
	public ConstraintsSet TYPEExpr(TypeAssumptions assumptions) {
		ConstraintsSet ret = new ConstraintsSet();
		//Die Assumptions für die Parameter der LambdaExpression
		TypeAssumptions ArgumentAssumptions = new TypeAssumptions(assumptions.getThisValue().getName());
		Vector<Type> paramTypes =  new Vector<Type>();
		
		for(FormalParameter param : params.formalparameter){
			if(param.getTypeVariable()==null)param.setTypeVariable(TypePlaceholder.fresh(this));
			int offset = 0;
			//Jeder Parameter der LambdaExpression wird als CParaTypeAssumption der Assumption liste hinzugefügt:
			ArgumentAssumptions.add(new CParaTypeAssumption("", "", offset, offset, param.get_Name(), param.getTypeVariable(), offset, offset, null));
			paramTypes.add(param.getTypeVariable());
		}
		this.setTypeVariable(TypePlaceholder.fresh(this));
		//ArgumentAssumptions + assumptions ergeben die Assumptions für die Statements innerhalb des Lambda-Bodys:
		ret.add(method_body.TYPEStmt(ArgumentAssumptions.add(assumptions))); //Es gibt die LambdaExpression nur mit einem Block als Method Body, nicht mit einer einzelnen Expression
		ret.add(new SingleConstraint(new FunN(method_body.getTypeVariable(), paramTypes),this.getTypeVariable()));
		return ret;
	}
	
	@Override
	public ConstraintsSet TYPEStmt(TypeAssumptions ass){
		throw new TypinferenzException("Eine LambdaExpression darf nicht als Statement verwendet werden.");
	}
	
	@Override
	public String getTypeInformation(){
		return this.getTypeVariable().toString()+" :: ("+this.params.getTypeInformation()+ ") -> " +this.method_body.getTypeInformation();
	}
	
	@Override
	public String toString(){
		//return "LambdaExpression, Parameter: "+this.params+ ", Body: " +this.method_body;
		return this.getType() +  " (("+this.params+ ") -> "+this.method_body + ")";
	}
	
	@Override
	public JavaCodeResult printJavaCode(ResultSet resultSet){
		JavaCodeResult ret = new JavaCodeResult();
		ret.attach( "(").attach(this.params.printJavaCode(resultSet)).attach(")");
		ret.attach( " -> ").attach( this.method_body.printJavaCode(resultSet));
		return ret;
	}

}