package com.ctc.wstx.io;

import java.io.*;

import javax.xml.stream.Location;
import javax.xml.stream.XMLStreamException;

import com.ctc.wstx.api.ReaderConfig;
import com.ctc.wstx.cfg.ErrorConsts;
import com.ctc.wstx.cfg.XmlConsts;
import com.ctc.wstx.exc.*;

Abstract base class that defines common API used with both stream and
reader-based input sources. Class is responsible for opening the physical
input source, figure out encoding (if necessary; only for streams), and
then handle (optional) XML declaration.
/**
 * Abstract base class that defines common API used with both stream and
 * reader-based input sources. Class is responsible for opening the physical
 * input source, figure out encoding (if necessary; only for streams), and
 * then handle (optional) XML declaration.
 */
public abstract class InputBootstrapper
{
    /*
    ////////////////////////////////////////////////////////////
    // Shared string consts
    ////////////////////////////////////////////////////////////
     */

    protected final static String ERR_XMLDECL_KW_VERSION = "; expected keyword '"+XmlConsts.XML_DECL_KW_VERSION+"'";
    protected final static String ERR_XMLDECL_KW_ENCODING = "; expected keyword '"+XmlConsts.XML_DECL_KW_ENCODING+"'";
    protected final static String ERR_XMLDECL_KW_STANDALONE = "; expected keyword '"+XmlConsts.XML_DECL_KW_STANDALONE+"'";

    protected final static String ERR_XMLDECL_END_MARKER = "; expected \"?>\" end marker";

    protected final static String ERR_XMLDECL_EXP_SPACE = "; expected a white space";
    protected final static String ERR_XMLDECL_EXP_EQ = "; expected '=' after ";
    protected final static String ERR_XMLDECL_EXP_ATTRVAL = "; expected a quote character enclosing value for ";

    /*
    ////////////////////////////////////////////////////////////
    // Other consts
    ////////////////////////////////////////////////////////////
     */

    public final static char CHAR_NULL = (char) 0;
    public final static char CHAR_SPACE = (char) 0x0020;

    public final static char CHAR_NEL = (char) 0x0085;

    public final static byte CHAR_CR = '\r';
    public final static byte CHAR_LF = '\n';

    public final static byte BYTE_NULL = (byte) 0;

    public final static byte BYTE_CR = (byte) '\r';
    public final static byte BYTE_LF = (byte) '\n';

    /*
    ////////////////////////////////////////////////////////////
    // Input source info
    ////////////////////////////////////////////////////////////
     */

    protected final String mPublicId;

    protected final SystemId mSystemId;

    /*
    ////////////////////////////////////////////////////////////
    // Input location data (similar to one in WstxInputData)
    ////////////////////////////////////////////////////////////
     */

    
Current number of characters that were processed in previous blocks,
before contents of current input buffer.
/**
     * Current number of characters that were processed in previous blocks,
     * before contents of current input buffer.
     */
    protected int mInputProcessed = 0;

    
Current row location of current point in input buffer, starting
from 1
/**
     * Current row location of current point in input buffer, starting
     * from 1
     */
    protected int mInputRow = 1;

    
Current index of the first character of the current row in input
buffer. Needed to calculate column position, if necessary; benefit
of not having column itself is that this only has to be updated
once per line.
/**
     * Current index of the first character of the current row in input
     * buffer. Needed to calculate column position, if necessary; benefit
     * of not having column itself is that this only has to be updated
     * once per line.
     */
    protected int mInputRowStart = 0;

    /*
    ////////////////////////////////////////
    // Info from XML declaration
    ////////////////////////////////////////
    */

    //boolean mHadDeclaration = false;

    
XML declaration from the input (1.0, 1.1 or 'unknown')
/**
     * XML declaration from the input (1.0, 1.1 or 'unknown')
     */
    int mDeclaredXmlVersion = XmlConsts.XML_V_UNKNOWN;

    
Value of encoding pseudo-attribute from xml declaration, if
one was found; null otherwise.
/**
     * Value of encoding pseudo-attribute from xml declaration, if
     * one was found; null otherwise.
     */
    String mFoundEncoding;

    String mStandalone;

    
Flag that indicates whether input read from this input source
needs to be xml 1.1 compliant or not; if not, xml 1.0 is assumed.
State of this flag depends on parent context (if one existed), or if
not, on xml declaration of this input source.
/**
     * Flag that indicates whether input read from this input source
     * needs to be xml 1.1 compliant or not; if not, xml 1.0 is assumed.
     * State of this flag depends on parent context (if one existed), or if
     * not, on xml declaration of this input source.
     */
    boolean mXml11Handling = false;

    /*
    ////////////////////////////////////////
    // Temporary data
    ////////////////////////////////////////
    */

    
Need a short buffer to read in values of pseudo-attributes (version,
encoding, standalone). Don't really need tons of space; just enough
for the longest anticipated encoding id... and maybe few chars just
in case (for additional white space that we ignore)
/**
     * Need a short buffer to read in values of pseudo-attributes (version,
     * encoding, standalone). Don't really need tons of space; just enough
     * for the longest anticipated encoding id... and maybe few chars just
     * in case (for additional white space that we ignore)
     */
    final char[] mKeyword = new char[60];

    /*
    ////////////////////////////////////////
    // Life-cycle
    ////////////////////////////////////////
    */

    protected InputBootstrapper(String pubId, SystemId sysId)
    {
        mPublicId = pubId;
        mSystemId = sysId;
    }

    protected void initFrom(InputBootstrapper src)
    {
        mInputProcessed = src.mInputProcessed;
        mInputRow = src.mInputRow;
        mInputRowStart = src.mInputRowStart;
        mDeclaredXmlVersion = src.mDeclaredXmlVersion;
        mFoundEncoding = src.mFoundEncoding;
        mStandalone = src.mStandalone;
        mXml11Handling = src.mXml11Handling;
    }

    /*
    ////////////////////////////////////////
    // Public API
    ////////////////////////////////////////
    */

    
Params:
xmlVersion – Optional xml version identifier of the main parsed
  document (if not bootstrapping the main document).
  Currently only relevant for checking that XML 1.0 document does not
  include XML 1.1 external parsed entities.
  If null, no checks will be done; when bootstrapping parsing of the
  main document, null should be passed for this argument./**
     * @param xmlVersion Optional xml version identifier of the main parsed
     *   document (if not bootstrapping the main document).
     *   Currently only relevant for checking that XML 1.0 document does not
     *   include XML 1.1 external parsed entities.
     *   If null, no checks will be done; when bootstrapping parsing of the
     *   main document, null should be passed for this argument.
     */
    public abstract Reader bootstrapInput(ReaderConfig cfg, boolean mainDoc,
                                          int xmlVersion)
        throws IOException, XMLStreamException;

    // // // Source information:

    public String getPublicId() { return mPublicId; }

    public SystemId getSystemId() { return mSystemId; }

    // // // XML declaration data:

    public int getDeclaredVersion()
    {
        return mDeclaredXmlVersion;
    }

    
Returns:
True, if the input bootstrapped declared that it conforms
  to xml 1.1 (independent of where it was included from)/**
     * @return True, if the input bootstrapped declared that it conforms
     *   to xml 1.1 (independent of where it was included from)
     */
    public boolean declaredXml11() {
        return (mDeclaredXmlVersion == XmlConsts.XML_V_11);
    }

    public String getStandalone() {
        return mStandalone;
    }

    
Returns:
Encoding declaration found from the xml declaration, if any;
   null if none./**
     * @return Encoding declaration found from the xml declaration, if any;
     *    null if none.
     */
    public String getDeclaredEncoding() {
        return mFoundEncoding;
    }

    // // // Location/position info:

    
Returns:
Total number of characters read from bootstrapped input
  (stream, reader)/**
     * @return Total number of characters read from bootstrapped input
     *   (stream, reader)
     */
    public abstract int getInputTotal();

    public int getInputRow() {
        return mInputRow;
    }

    public abstract int getInputColumn();


    // // // Misc other info

    
Actual character encoding used by the underlying input source;
may have been passed by the application, or auto-detected
by byte stream boot strapper (can not be determined from a
Reader source).
Returns:
Input encoding in use, if it could be determined or was 
  passed by the calling application/**
     * Actual character encoding used by the underlying input source;
     * may have been passed by the application, or auto-detected
     * by byte stream boot strapper (can not be determined from a
     * Reader source).
     *
     * @return Input encoding in use, if it could be determined or was 
     *   passed by the calling application
     */
    public abstract String getInputEncoding();

    /*
    ////////////////////////////////////////
    // Package methods, parsing
    ////////////////////////////////////////
    */

    
Params:
xmlVersion – Optional xml version identifier of the main parsed
  document (if not bootstrapping the main document).
  Currently only relevant for checking that XML 1.0 document does not
  include XML 1.1 external parsed entities.
  If null, no checks will be done; when bootstrapping parsing of the
  main document, null should be passed for this argument./**
     * @param xmlVersion Optional xml version identifier of the main parsed
     *   document (if not bootstrapping the main document).
     *   Currently only relevant for checking that XML 1.0 document does not
     *   include XML 1.1 external parsed entities.
     *   If null, no checks will be done; when bootstrapping parsing of the
     *   main document, null should be passed for this argument.
     */
    protected void readXmlDecl(boolean isMainDoc, int xmlVersion)
        throws IOException, WstxException
    {
        int c = getNextAfterWs(false);

        // First, version pseudo-attribute:

        if (c != 'v') { // version info obligatory for main docs
            if (isMainDoc) {
                reportUnexpectedChar(c, ERR_XMLDECL_KW_VERSION);
            }
        } else { // ok, should be version
            mDeclaredXmlVersion = readXmlVersion();
            c = getWsOrChar('?');
        }

        /* 17-Feb-2006, TSa: Whether we are to be xml 1.1 compliant or not
         *   depends on parent context, if any; and if not, on actual
         *   xml declaration. But in former case, it is illegal to include
         *   xml 1.1 declared entities from xml 1.0 context.
         */
        boolean thisIs11 = (mDeclaredXmlVersion == XmlConsts.XML_V_11);
        if (xmlVersion != XmlConsts.XML_V_UNKNOWN) { // happens when reading main doc
            mXml11Handling = (XmlConsts.XML_V_11 == xmlVersion);
            // Can not refer to xml 1.1 entities from 1.0 doc:
            if (thisIs11 && !mXml11Handling) {
                reportXmlProblem(ErrorConsts.ERR_XML_10_VS_11);
            }
        } else {
            mXml11Handling = thisIs11;
        }

        // Then, 'encoding'
        if (c != 'e') { // obligatory for external entities
            if (!isMainDoc) {
                reportUnexpectedChar(c, ERR_XMLDECL_KW_ENCODING);
            }
        } else {
            mFoundEncoding = readXmlEncoding();
            c = getWsOrChar('?');
        }

        // Then, 'standalone' (for main doc)
        if (isMainDoc && c == 's') {
            mStandalone = readXmlStandalone();
            c = getWsOrChar('?');
        }

        // And finally, need to have closing markers

        if (c != '?') {
            reportUnexpectedChar(c, ERR_XMLDECL_END_MARKER);
        }
        c = getNext();
        if (c != '>') {
            reportUnexpectedChar(c, ERR_XMLDECL_END_MARKER);
        }
    }

    
Returns:
Xml version declaration read/**
     * @return Xml version declaration read
     */
    private final int readXmlVersion()
        throws IOException, WstxException
    {
        int c = checkKeyword(XmlConsts.XML_DECL_KW_VERSION);
        if (c != CHAR_NULL) {
            reportUnexpectedChar(c, XmlConsts.XML_DECL_KW_VERSION);
        }
        c = handleEq(XmlConsts.XML_DECL_KW_VERSION);
        int len = readQuotedValue(mKeyword, c);

        if (len == 3) {
            if (mKeyword[0] == '1' && mKeyword[1] == '.') {
                c = mKeyword[2];
                if (c == '0') {
                    return XmlConsts.XML_V_10;
                }
                if (c == '1') {
                    return XmlConsts.XML_V_11;
                }
            }
        }

        // Nope; error. -1 indicates run off...
        String got;

        if (len < 0) {
            got = "'"+new String(mKeyword)+"[..]'";
        } else if (len == 0) {
            got = "<empty>";
        } else {
            got = "'"+new String(mKeyword, 0, len)+"'";
        }
        reportPseudoAttrProblem(XmlConsts.XML_DECL_KW_VERSION, got,
                                XmlConsts.XML_V_10_STR, XmlConsts.XML_V_11_STR);
        return XmlConsts.XML_V_UNKNOWN; // never gets here, but compiler needs it
    }

    private final String readXmlEncoding()
        throws IOException, WstxException
    {
        int c = checkKeyword(XmlConsts.XML_DECL_KW_ENCODING);
        if (c != CHAR_NULL) {
            reportUnexpectedChar(c, XmlConsts.XML_DECL_KW_ENCODING);
        }
        c = handleEq(XmlConsts.XML_DECL_KW_ENCODING);

        int len = readQuotedValue(mKeyword, c);

        /* Hmmh. How about "too long" encodings? Maybe just truncate them,
         * for now?
         */
        if (len == 0) { // let's still detect missing value...
            reportPseudoAttrProblem(XmlConsts.XML_DECL_KW_ENCODING, null,
                                    null, null);
        }

        if (len < 0) { // will be truncated...
            return new String(mKeyword);
        }
        return new String(mKeyword, 0, len);
    }

    private final String readXmlStandalone()
        throws IOException, WstxException
    {
        int c = checkKeyword(XmlConsts.XML_DECL_KW_STANDALONE);
        if (c != CHAR_NULL) {
            reportUnexpectedChar(c, XmlConsts.XML_DECL_KW_STANDALONE);
        }
        c = handleEq(XmlConsts.XML_DECL_KW_STANDALONE);
        int len = readQuotedValue(mKeyword, c);

        if (len == 2) {
            if (mKeyword[0] == 'n' && mKeyword[1] == 'o') {
                return XmlConsts.XML_SA_NO;
            }
        } else if (len == 3) {
            if (mKeyword[0] == 'y' && mKeyword[1] == 'e'
                && mKeyword[2] == 's') {
                return XmlConsts.XML_SA_YES;
            }
        }

        // Nope; error. -1 indicates run off...
        String got;

        if (len < 0) {
            got = "'"+new String(mKeyword)+"[..]'";
        } else if (len == 0) {
            got = "<empty>";
        } else {
            got = "'"+new String(mKeyword, 0, len)+"'";
        }

        reportPseudoAttrProblem(XmlConsts.XML_DECL_KW_STANDALONE, got,
                                XmlConsts.XML_SA_YES, XmlConsts.XML_SA_NO);
        return got; // never gets here, but compiler can't figure it out
    }

    private final int handleEq(String attr)
        throws IOException, WstxException
    {
        int c = getNextAfterWs(false);
        if (c != '=') {
            reportUnexpectedChar(c, ERR_XMLDECL_EXP_EQ+"'"+attr+"'");
        }

        c = getNextAfterWs(false);
        if (c != '"' && c != '\'') {
            reportUnexpectedChar(c, ERR_XMLDECL_EXP_ATTRVAL+"'"+attr+"'");
        }
        return c;
    }

    
Method that should get next character, which has to be either specified
character (usually end marker), OR, any character as long as there'
at least one space character before it.
/**
     * Method that should get next character, which has to be either specified
     * character (usually end marker), OR, any character as long as there'
     * at least one space character before it.
     */
    private final int getWsOrChar(int ok)
        throws IOException, WstxException
    {
        int c = getNext();
        if (c == ok) {
            return c;
        }
        if (c > CHAR_SPACE) {
            reportUnexpectedChar(c, "; expected either '"+((char) ok)+"' or white space");
        }
        if (c == CHAR_LF || c == CHAR_CR) {
            // Need to push it back to be processed properly
            pushback();
        }
        return getNextAfterWs(false);
    }

    /*
    ////////////////////////////////////////////////////////
    // Abstract parsing methods for sub-classes to implement
    ////////////////////////////////////////////////////////
    */

    protected abstract void pushback();

    protected abstract int getNext()
        throws IOException, WstxException;

    protected abstract int getNextAfterWs(boolean reqWs)
        throws IOException, WstxException;

    
Returns:
First character that does not match expected, if any;
   CHAR_NULL if match succeeded/**
     * @return First character that does not match expected, if any;
     *    CHAR_NULL if match succeeded
     */
    protected abstract int checkKeyword(String exp)
        throws IOException, WstxException;

    protected abstract int readQuotedValue(char[] kw, int quoteChar)
        throws IOException, WstxException;

    protected abstract Location getLocation();

    /*
    ////////////////////////////////////////////////////////
    // Package methods available to sub-classes:
    ////////////////////////////////////////////////////////
    */

    protected void reportNull()
        throws WstxException
    {
        throw new WstxException("Illegal null byte in input stream",
                                getLocation());
    }

    protected void reportXmlProblem(String msg)
        throws WstxException
    {
        throw new WstxParsingException(msg, getLocation());
    }

    protected void reportUnexpectedChar(int i, String msg)
        throws WstxException
    {
        char c = (char) i;
        String excMsg;

        // WTF? JDK thinks null char is just fine as?!
        if (Character.isISOControl(c)) {
            excMsg = "Unexpected character (CTRL-CHAR, code "+i+")"+msg;
        } else {
            excMsg = "Unexpected character '"+c+"' (code "+i+")"+msg;
        }
        Location loc = getLocation();
        throw new WstxUnexpectedCharException(excMsg, loc, c);
    }

    /*
    ////////////////////////////////////////
    // Other private methods:
    ////////////////////////////////////////
    */

    private final void reportPseudoAttrProblem(String attrName, String got,
                                               String expVal1, String expVal2)
        throws WstxException
    {
        String expStr = (expVal1 == null) ? "" :
            ("; expected \""+expVal1+"\" or \""+expVal2+"\"");

        if (got == null || got.length() == 0) {
            throw new WstxParsingException("Missing XML pseudo-attribute '"+attrName+"' value"+expStr,
                                           getLocation());
        }
        throw new WstxParsingException("Invalid XML pseudo-attribute '"+attrName+"' value "+got+expStr,
                                       getLocation());
    }
}