/* ====================================================================
   Licensed to the Apache Software Foundation (ASF) under one or more
   contributor license agreements.  See the NOTICE file distributed with
   this work for additional information regarding copyright ownership.
   The ASF licenses this file to You under the Apache License, Version 2.0
   (the "License"); you may not use this file except in compliance with
   the License.  You may obtain a copy of the License at

       http://www.apache.org/licenses/LICENSE-2.0

   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   See the License for the specific language governing permissions and
   limitations under the License.
==================================================================== */

package org.apache.poi.ss.formula.ptg;

import org.apache.poi.ss.formula.function.FunctionMetadata;
import org.apache.poi.ss.formula.function.FunctionMetadataRegistry;
import org.apache.poi.util.LittleEndianInput;
import org.apache.poi.util.LittleEndianOutput;

public final class FuncPtg extends AbstractFunctionPtg {

    public static final byte sid  = 0x21;
    public static final int  SIZE = 3;

    public static FuncPtg create(LittleEndianInput in) {
        return create(in.readUShort());
    }

    private FuncPtg(int funcIndex, FunctionMetadata fm) {
        super(funcIndex, fm.getReturnClassCode(), fm.getParameterClassCodes(), fm.getMinParams());  // minParams same as max since these are not var-arg funcs
    }

    public static FuncPtg create(int functionIndex) {
        FunctionMetadata fm = FunctionMetadataRegistry.getFunctionByIndex(functionIndex);
        if(fm == null) {
            throw new IllegalStateException("Invalid built-in function index (" + functionIndex + ")");
        }
        return new FuncPtg(functionIndex, fm);
    }


    public void write(LittleEndianOutput out) {
        out.writeByte(sid + getPtgClass());
        out.writeShort(getFunctionIndex());
    }

    @Override
    public byte getSid() {
        return sid;
    }

    public int getSize() {
        return SIZE;
    }

    @Override
    public FuncPtg copy() {
        // immutable
        return this;
    }
}
