package com.tom_roush.pdfbox.pdmodel.interactive.annotation;

import java.util.HashMap;
import java.util.Map;

import com.tom_roush.pdfbox.cos.COSBase;
import com.tom_roush.pdfbox.cos.COSDictionary;
import com.tom_roush.pdfbox.cos.COSName;
import com.tom_roush.pdfbox.cos.COSStream;
import com.tom_roush.pdfbox.pdmodel.common.COSDictionaryMap;
import com.tom_roush.pdfbox.pdmodel.common.COSObjectable;

/**
 * An entry in an appearance dictionary. May contain either a single appearance stream or an
 * appearance subdictionary.
 *
 * @author John Hewson
 */
public class PDAppearanceEntry implements COSObjectable
{
    private COSBase entry;

    private PDAppearanceEntry()
    {
    }

    /**
     * Constructor for reading.
     * @param entry
     */
    public PDAppearanceEntry(COSBase entry)
    {
        this.entry = entry;
    }

    @Override
    public COSBase getCOSObject()
    {
        return entry;
    }

    /**
     * Returns true if this entry is an appearance subdictionary.
     */
    public boolean isSubDictionary()
    {
        return !(this.entry instanceof COSStream);
    }

    /**
     * Returns true if this entry is an appearance stream.
     */
    public boolean isStream()
    {
        return this.entry instanceof COSStream;
    }

    /**
     * Returns the entry as an appearance stream.
     *
     * @throws IllegalStateException if this entry is not an appearance stream
     */
    public PDAppearanceStream getAppearanceStream()
    {
        if (!isStream())
        {
            throw new IllegalStateException();
        }
        return new PDAppearanceStream((COSStream)entry);
    }

    /**
     * Returns the entry as an appearance subdictionary.
     *
     * @throws IllegalStateException if this entry is not an appearance subdictionary
     */
    public Map<COSName, PDAppearanceStream> getSubDictionary()
    {
        if (!isSubDictionary())
        {
            throw new IllegalStateException();
        }

        COSDictionary dict = (COSDictionary)entry;
        Map<COSName, PDAppearanceStream> map = new HashMap<COSName, PDAppearanceStream>();

        for (COSName name : dict.keySet())
        {
            COSBase value = dict.getDictionaryObject(name);

            // the file from PDFBOX-1599 contains /null as its entry, so we skip non-stream entries
            if(value instanceof COSStream)
            {
                map.put(name, new PDAppearanceStream((COSStream)value));
            }
        }

        return new COSDictionaryMap<COSName, PDAppearanceStream>( map, dict );
    }
}