package org.simantics.scl.compiler.elaboration.chr;

import org.cojen.classfile.TypeDesc;
import org.simantics.scl.compiler.common.exceptions.InternalCompilerError;
import org.simantics.scl.compiler.constants.Constant;
import org.simantics.scl.compiler.constants.JavaConstructor;
import org.simantics.scl.compiler.internal.codegen.chr.CHRRuntimeRulesetCodeGenerator;
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.ssa.SSAFunction;
import org.simantics.scl.compiler.internal.codegen.ssa.SSAObject;
import org.simantics.scl.compiler.internal.codegen.utils.LocalVariable;
import org.simantics.scl.compiler.internal.codegen.utils.MethodBuilder;
import org.simantics.scl.compiler.internal.codegen.utils.ModuleBuilder;
import org.simantics.scl.compiler.types.Types;

import gnu.trove.map.hash.TObjectIntHashMap;
import gnu.trove.procedure.TIntProcedure;
import gnu.trove.set.hash.TIntHashSet;

public class CHRRulesetObject extends SSAObject {
    CHRRuleset ruleset;

    public BoundVar this_;
    public BoundVar[] parameters;
    public TObjectIntHashMap<BoundVar> parameterIndexMap; 
    public TypeDesc[] parameterTypeDescs;
    
    public CHRRulesetObject(BoundVar target, CHRRuleset ruleset) {
        super(ruleset.runtimeRulesetType);
        this.setTarget(target);
        this.ruleset = ruleset;
    }
    
    @Override
    public Constant liftClosure(BoundVar newTarget, BoundVar[] parameters) {
        ruleset.rulesetObject = this;
        this.this_ = newTarget;
        this.parameters = parameters;
        this.parameterIndexMap = new TObjectIntHashMap<>(parameters.length);
        for(int i=0;i<parameters.length;++i)
            this.parameterIndexMap.put(parameters[i], i);
        return new JavaConstructor(ruleset.runtimeRulesetClassName, Types.PROC, ruleset.runtimeRulesetType, Types.getTypes(parameters));
    }
    
    @Override
    public void generateCode(ModuleBuilder moduleBuilder) {
        CHRRuntimeRulesetCodeGenerator.generateRuntimeRuleset(moduleBuilder, ruleset);
    }
    
    @FunctionalInterface
    public interface ParameterDefiner {
        public void defineParameter(int index, BoundVar var);
    }
    
    public void realizeMethod(MethodBuilder mb, ParameterDefiner loader, SSAFunction function, LocalVariable this_, LocalVariable ... callParameters) {
        mb.setLocalVariable(this.this_, this_);
        BoundVar[] functionParameters = function.getParameters();
        if(functionParameters.length != callParameters.length)
            throw new InternalCompilerError();
        for(int i=0;i<callParameters.length;++i)
            mb.setLocalVariable(functionParameters[i], callParameters[i]);

        // Set closure parameters
        TIntHashSet usedParameterIndices = new TIntHashSet(parameters.length);
        function.forValRefs(valRef -> {
            Val binding = valRef.getBinding();
            if(parameterIndexMap.containsKey(binding))
                usedParameterIndices.add(parameterIndexMap.get((BoundVar)binding));
        });
        usedParameterIndices.forEach(new TIntProcedure() {
            @Override
            public boolean execute(int i) {
                loader.defineParameter(i, parameters[i]);
                return true;
            }
        });

        // Generate code
        function.markGenerateOnFly();
        function.generateCodeWithAlreadyPreparedParameters(mb);
    }
}