package org.simantics.scl.compiler.internal.codegen.ssa;

import java.util.ArrayList;

import org.simantics.scl.compiler.internal.codegen.references.BoundVar;
import org.simantics.scl.compiler.internal.codegen.references.Val;
import org.simantics.scl.compiler.internal.codegen.references.ValRef;
import org.simantics.scl.compiler.internal.codegen.ssa.statements.LetApply;
import org.simantics.scl.compiler.internal.codegen.utils.CopyContext;
import org.simantics.scl.compiler.internal.codegen.utils.MethodBuilder;
import org.simantics.scl.compiler.internal.codegen.utils.Printable;
import org.simantics.scl.compiler.internal.codegen.utils.PrintingContext;
import org.simantics.scl.compiler.internal.codegen.utils.SSALambdaLiftingContext;
import org.simantics.scl.compiler.internal.codegen.utils.SSASimplificationContext;
import org.simantics.scl.compiler.internal.codegen.utils.SSAValidationContext;
import org.simantics.scl.compiler.internal.codegen.utils.ValRefVisitor;
import org.simantics.scl.compiler.types.TVar;
import org.simantics.scl.compiler.types.Type;
import org.simantics.scl.compiler.types.Types;


public abstract class SSAStatement implements Printable {
    SSABlock parent;
    SSAStatement prev;
    SSAStatement next;
    public long location;
    
    public void detach() {
        if(prev == null)
            parent.firstStatement = next;
        else
            prev.next = next;
        if(next == null)
            parent.lastStatement = prev;
        else
            next.prev = prev;
    }

    public abstract void generateCode(MethodBuilder mb);

    public abstract void validate(SSAValidationContext context);

    public void simplify(SSASimplificationContext context) {
    }

    public abstract void destroy();
    
    public SSABlock getParent() {
        return parent;
    }
    
    public SSAStatement getPrev() {
        return prev;
    }
    
    public void setAsLastStatement() {
        this.next = null;
        parent.lastStatement = this;
    }
    
    public SSAStatement getNext() {
        return next;
    }
    
    public void remove() {
        detach();
        destroy();        
    }
    
    @Override
    public String toString() {
        PrintingContext context = new PrintingContext();
        toString(context);
        return context.toString();
    }

    public void markGenerateOnFly() {        
    }

    public abstract SSAStatement copy(CopyContext context);
    public abstract void replace(TVar[] vars, Type[] replacements);

    public abstract void addBoundVariablesTo(SSAValidationContext context);

    public abstract void collectFreeVariables(SSAFunction function, ArrayList<ValRef> vars);
    
    public SSAFunction getParentFunction() {
        return parent.parent;
    }

    public void lambdaLift(SSALambdaLiftingContext context) {
    }
    
    public void insertBefore(SSAStatement statement) {
        next = statement;
        prev = statement.prev;
        parent = statement.parent;
        if(prev == null)
            parent.firstStatement = this;
        else
            prev.next = this;
        statement.prev = this;        
    }
    
    public void insertAfter(SSAStatement statement) {
        prev = statement;
        next = statement.next;
        parent = statement.parent;
        if(next == null)
            parent.lastStatement = this;
        else
            next.prev = this;
        statement.next = this;        
    }
    
    public void replaceByApply(ValRef valRef, Val function, Type[] typeParameters, Val[] parameters) {
        BoundVar target = new BoundVar(valRef.getBinding().getType());
        new LetApply(target, Types.NO_EFFECTS, function.createOccurrence(typeParameters), ValRef.createOccurrences(parameters)).insertBefore(this);
        valRef.replaceBy(target);
    }

    public void prepare(MethodBuilder mb) {        
    }

    public abstract void forValRefs(ValRefVisitor visitor);
}