/* ====================================================================
   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.hssf.dev;

import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.util.List;

import org.apache.poi.hssf.model.HSSFFormulaParser;
import org.apache.poi.hssf.record.FormulaRecord;
import org.apache.poi.hssf.record.RecordFactory;
import org.apache.poi.poifs.filesystem.POIFSFileSystem;
import org.apache.poi.ss.formula.ptg.ExpPtg;
import org.apache.poi.ss.formula.ptg.FuncPtg;
import org.apache.poi.ss.formula.ptg.Ptg;

/**
 * FormulaViewer - finds formulas in a BIFF8 file and attempts to read them/display
 * data from them. Only works if Formulas are enabled in "RecordFactory"
 */
public class FormulaViewer
{
    private String file;
    private boolean list;

    /** Creates new FormulaViewer */

    public FormulaViewer()
    {
    }

    /**
     * Method run
     *
     * @throws IOException if the file contained errors
     */
    public void run() throws IOException {
        try (POIFSFileSystem fs = new POIFSFileSystem(new File(file), true)) {
            try (InputStream is = BiffViewer.getPOIFSInputStream(fs)) {
                List<org.apache.poi.hssf.record.Record> records = RecordFactory.createRecords(is);

                for (org.apache.poi.hssf.record.Record record : records) {
                    if (record.getSid() == FormulaRecord.sid) {
                        if (list) {
                            listFormula((FormulaRecord) record);
                        } else {
                            parseFormulaRecord((FormulaRecord) record);
                        }
                    }
                }
            }
        }
    }

    private void listFormula(FormulaRecord record) {
        Ptg[] tokens= record.getParsedExpression();
        int numptgs = tokens.length;
        final Ptg lastToken = tokens[numptgs-1];

        if (lastToken instanceof ExpPtg) return;

        String buf = String.join("~",
            lastToken.toFormulaString(),
            mapToken(lastToken),
            (numptgs > 1 ? mapToken(tokens[numptgs - 2]) : "VALUE"),
            String.valueOf(lastToken instanceof FuncPtg ? numptgs-1 : -1)
        );

        System.out.println(buf);
    }

    private static String mapToken(Ptg token) {
        switch (token.getPtgClass()) {
            case Ptg.CLASS_REF :
                return "REF";
            case Ptg.CLASS_VALUE :
                return "VALUE";
            case Ptg.CLASS_ARRAY :
                return "ARRAY";
            default:
                throwInvalidRVAToken(token);
                return "";
        }
    }

    /**
     * Method parseFormulaRecord
     *
     * @param record the record to be parsed
     */
    public void parseFormulaRecord(FormulaRecord record)
    {
        System.out.println("==============================");
        System.out.print("row = " + record.getRow());
        System.out.println(", col = " + record.getColumn());
        System.out.println("value = " + record.getValue());
        System.out.print("xf = " + record.getXFIndex());
        System.out.print(", number of ptgs = "
                           + record.getParsedExpression().length);
        System.out.println(", options = " + record.getOptions());
        System.out.println("RPN List = "+formulaString(record));
        System.out.println("Formula text = "+ composeFormula(record));
    }

    private String formulaString(FormulaRecord record) {

        StringBuilder buf = new StringBuilder();
		Ptg[] tokens = record.getParsedExpression();
		for (Ptg token : tokens) {
			buf.append( token.toFormulaString());
            switch (token.getPtgClass()) {
                case Ptg.CLASS_REF :
                    buf.append("(R)");
                    break;
                case Ptg.CLASS_VALUE :
                    buf.append("(V)");
                    break;
                case Ptg.CLASS_ARRAY :
                    buf.append("(A)");
                    break;
                default:
                    throwInvalidRVAToken(token);
            }
            buf.append(' ');
        }
        return buf.toString();
    }

    private static void throwInvalidRVAToken(Ptg token) {
        throw new IllegalStateException("Invalid RVA type (" + token.getPtgClass() + "). This should never happen.");
    }


    private static String composeFormula(FormulaRecord record)
    {
       return  HSSFFormulaParser.toFormulaString(null, record.getParsedExpression());
    }

    /**
     * Method setFile
     *
     * @param file the file to process
     */

    public void setFile(String file)
    {
        this.file = file;
    }

    public void setList(boolean list) {
        this.list=list;
    }

    /**
     * Method main
     *
     * pass me a filename and I'll try and parse the formulas from it
     *
     * @param args pass one argument with the filename or --help
     * @throws IOException if the file can't be read or contained errors
     */
    public static void main(String[] args) throws IOException
    {
        if ((args == null) || (args.length >2 )
                || args[ 0 ].equals("--help"))
        {
            System.out.println(
                "FormulaViewer .8 proof that the devil lies in the details (or just in BIFF8 files in general)");
            System.out.println("usage: Give me a big fat file name");
        } else if (args[0].equals("--listFunctions")) { // undocumented attribute to research functions!~
            FormulaViewer viewer = new FormulaViewer();
            viewer.setFile(args[1]);
            viewer.setList(true);
            viewer.run();
        }
        else
        {
            FormulaViewer viewer = new FormulaViewer();

            viewer.setFile(args[ 0 ]);
            viewer.run();
        }
    }
}