package com.drew.metadata.iptc;

import com.drew.lang.annotations.NotNull;
import com.drew.lang.annotations.Nullable;

import java.nio.ByteBuffer;
import java.nio.charset.CharacterCodingException;
import java.nio.charset.Charset;
import java.nio.charset.CharsetDecoder;

public final class Iso2022Converter
{
    private static final String ISO_8859_1 = "ISO-8859-1";
    private static final String UTF_8 = "UTF-8";
    private static final int LATIN_CAPITAL_A = 0x41;
    private static final int DOT = 0xe280a2;
    private static final int LATIN_CAPITAL_G = 0x47;
    private static final int PERCENT_SIGN = 0x25;
    private static final int ESC = 0x1B;

    /**
     * Converts the given ISO2022 char set to a java char set.
     *
     * @param bytes the ISO2022 char set
     * @return the java char set name as a string or null if the converting was not possible
     */
    @Nullable
    public static String convertISO2022CharsetToJavaCharset(@NotNull final byte[] bytes)
    {
        if (bytes.length > 2 && bytes[0] == ESC && bytes[1] == PERCENT_SIGN && bytes[2] == LATIN_CAPITAL_G)
            return UTF_8;

        if (bytes.length > 3 && bytes[0] == ESC && (bytes[3] & 0xFF | ((bytes[2] & 0xFF) << 8) | ((bytes[1] & 0xFF) << 16)) == DOT && bytes[4] == LATIN_CAPITAL_A)
            return ISO_8859_1;

        return null;
    }

    /**
     * This method tries to guess if the encoding is UTF-8, System.getProperty("file.encoding") or ISO-8859-1.
     * Its only purpose is to guess the encoding if and only if iptc tag coded character set is not set. If the
     * encoding is not UTF-8, the tag should be set. Otherwise it is bad practice. This method tries to
     * workaround this issue since some metadata manipulating tools do not prevent such bad practice.
     *
     * About the reliability of this method: The check if some bytes are UTF-8 or not has a very high reliability.
     * The two other checks are less reliable.
     *
     * @param bytes some text as bytes
     * @return the name of the encoding or null if none could be guessed
     */
    @Nullable
    static String guessEncoding(@NotNull final byte[] bytes)
    {
        CharsetDecoder cs = Charset.forName(UTF_8).newDecoder();

        try {
            cs.decode(ByteBuffer.wrap(bytes));
            return UTF_8;
        } catch (CharacterCodingException e) {
            // fall through...
        }

        cs = Charset.forName(System.getProperty("file.encoding")).newDecoder();
        try
        {
            cs.decode(ByteBuffer.wrap(bytes));
            return System.getProperty("file.encoding");
        } catch (CharacterCodingException e) {
            // fall through...
        }

        cs = Charset.forName(ISO_8859_1).newDecoder();
        try
        {
            cs.decode(ByteBuffer.wrap(bytes));
            return ISO_8859_1;
        } catch (CharacterCodingException e) {
            // fall through...
        }

        return null;
    }

    private Iso2022Converter()
    {}
}

@@ -2166,230 +2166,141 @@
     
-CharsetDecoder cs = Charset.forName(UTF_8).newDecoder();%0A%0A        try %7B%0A            cs.decode(ByteBuffer.wrap(bytes));%0A            return UTF_8;%0A        %7D catch (CharacterCodingException e) %7B%0A            // fall through...
+String%5B%5D encodings = %7B UTF_8, System.getProperty(%22file.encoding%22), ISO_8859_1 %7D;%0A%0A        for (String encoding : encodings)%0A        %7B
 %0A   
@@ -2300,34 +2300,42 @@
   %7B%0A        
-%7D%0A%0A
     
-   
+CharsetDecoder
  cs = Charse
@@ -2348,41 +2348,16 @@
 ame(
-System.getProperty(%22file.
 encoding
 %22)).
@@ -2352,18 +2352,16 @@
 encoding
-%22)
 ).newDec
@@ -2364,32 +2364,34 @@
 wDecoder();%0A
+%0A 
         
 try%0A        
@@ -2374,38 +2374,37 @@
 ;%0A%0A         
-try%0A   
+   try %7B%0A
     
- %7B%0A
             
@@ -2454,48 +2454,27 @@
     
+   
+ 
 return 
-System.getProperty(%22file.
 encoding
 %22);%0A
@@ -2473,12 +2473,14 @@
 ding
-%22)
 ;%0A
+    
     
@@ -2526,32 +2526,36 @@
 ) %7B%0A            
+  
+  
 // fall through.
@@ -2569,254 +2569,72 @@
     
-%7D%0A%0A
     
-    cs = Charset.forName(ISO_8859_1).newDecoder();%0A        try%0A        %7B%0A            cs.decode(ByteBuffer.wrap(bytes));%0A            return ISO_8859_1;%0A        %7D catch (CharacterCodingException e) %7B%0A            // fall through...%0A        %7D%0A
+%7D%0A        %7D%0A%0A        // No encodings succeeded. Return null.
 %0A   

Replace repeated statements with a loop.