package com.fasterxml.jackson.core.format;

import java.io.*;

import com.fasterxml.jackson.core.JsonFactory;
import com.fasterxml.jackson.core.JsonParser;
import com.fasterxml.jackson.core.io.MergedStream;

Result object constructed by DataFormatDetector when requested to detect format of given input data. /**
 * Result object constructed by {@link DataFormatDetector} when requested
 * to detect format of given input data.
 */
public class DataFormatMatcher
{
    protected final InputStream _originalStream;

    
Content read during format matching process
/**
     * Content read during format matching process
     */
    protected final byte[] _bufferedData;

    
Pointer to the first byte in buffer available for reading
/**
     * Pointer to the first byte in buffer available for reading
     */
    protected final int _bufferedStart;
    
    
Number of bytes available in buffer.
/**
     * Number of bytes available in buffer.
     */
    protected final int _bufferedLength;

    
Factory that produced sufficient match (if any)
/**
     * Factory that produced sufficient match (if any)
     */
    protected final JsonFactory _match;

    
Strength of match with _match /**
     * Strength of match with {@link #_match}
     */
    protected final MatchStrength _matchStrength;
    
    protected DataFormatMatcher(InputStream in, byte[] buffered,
            int bufferedStart, int bufferedLength,
            JsonFactory match, MatchStrength strength)
    {
        _originalStream = in;
        _bufferedData = buffered;
        _bufferedStart = bufferedStart;
        _bufferedLength = bufferedLength;
        _match = match;
        _matchStrength = strength;

        // can't have negative offset or length
        if ((bufferedStart | bufferedLength) < 0
                || (bufferedStart + bufferedLength) > buffered.length) {
            throw new IllegalArgumentException(String.format("Illegal start/length (%d/%d) wrt input array of %d bytes",
                    bufferedStart, bufferedLength, buffered.length));
        }
    }

    /*
    /**********************************************************
    /* Public API, simple accessors
    /**********************************************************
     */

    
Accessor to use to see if any formats matched well enough with
the input data.
/**
     * Accessor to use to see if any formats matched well enough with
     * the input data.
     */
    public boolean hasMatch() { return _match != null; }

    
Method for accessing strength of the match, if any; if no match, will return MatchStrength.INCONCLUSIVE. /**
     * Method for accessing strength of the match, if any; if no match,
     * will return {@link MatchStrength#INCONCLUSIVE}.
     */
    public MatchStrength getMatchStrength() {
        return (_matchStrength == null) ? MatchStrength.INCONCLUSIVE : _matchStrength;
    }

    
Accessor for JsonFactory that represents format that data matched. /**
     * Accessor for {@link JsonFactory} that represents format that data matched.
     */
    public JsonFactory getMatch() { return _match; }

    
Accessor for getting brief textual name of matched format if any (null
if none). Equivalent to:
  return hasMatch() ? getMatch().getFormatName() : null;

/**
     * Accessor for getting brief textual name of matched format if any (null
     * if none). Equivalent to:
     *<pre>
     *   return hasMatch() ? getMatch().getFormatName() : null;
     *</pre>
     */
    public String getMatchedFormatName() {
        return _match.getFormatName();
    }
    
    /*
    /**********************************************************
    /* Public API, factory methods
    /**********************************************************
     */
    
    
Convenience method for trying to construct a JsonParser for parsing content which is assumed to be in detected data format. If no match was found, returns null. /**
     * Convenience method for trying to construct a {@link JsonParser} for
     * parsing content which is assumed to be in detected data format.
     * If no match was found, returns null.
     */
    public JsonParser createParserWithMatch() throws IOException {
        if (_match == null) {
            return null;
        }
        if (_originalStream == null) {
            return _match.createParser(_bufferedData, _bufferedStart, _bufferedLength);
        }
        return _match.createParser(getDataStream());
    }
    
    
Method to use for accessing input for which format detection has been done.
This must be used instead of using stream passed to detector
unless given stream itself can do buffering.
Stream will return all content that was read during matching process, as well
as remaining contents of the underlying stream.
/**
     * Method to use for accessing input for which format detection has been done.
     * This <b>must</b> be used instead of using stream passed to detector
     * unless given stream itself can do buffering.
     * Stream will return all content that was read during matching process, as well
     * as remaining contents of the underlying stream.
     */
    public InputStream getDataStream() {
        if (_originalStream == null) {
            return new ByteArrayInputStream(_bufferedData, _bufferedStart, _bufferedLength);
        }
        return new MergedStream(null, _originalStream, _bufferedData, _bufferedStart, _bufferedLength);
    }
}