/*
 * Copyright (c) 2011 Adobe Systems Incorporated
 *
 *  Permission is hereby granted, free of charge, to any person obtaining a copy of
 *  this software and associated documentation files (the "Software"), to deal in
 *  the Software without restriction, including without limitation the rights to
 *  use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
 *  the Software, and to permit persons to whom the Software is furnished to do so,
 *  subject to the following conditions:
 *
 *  The above copyright notice and this permission notice shall be included in all
 *  copies or substantial portions of the Software.
 *
 *  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 *  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
 *  FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
 *  COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
 *  IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 *  CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 *
 */

package com.adobe.epubcheck.css;

import java.io.IOException;
import java.io.InputStream;
import java.io.StringReader;
import java.util.Locale;

import org.idpf.epubcheck.util.css.CssExceptions;
import org.idpf.epubcheck.util.css.CssParser;
import org.idpf.epubcheck.util.css.CssSource;

import com.adobe.epubcheck.api.EPUBLocation;
import com.adobe.epubcheck.api.Report;
import com.adobe.epubcheck.messages.MessageId;
import com.adobe.epubcheck.opf.ContentChecker;
import com.adobe.epubcheck.opf.ValidationContext;

public class CSSChecker implements ContentChecker
{
  private final ValidationContext context;
  private final Report report;
  private final String path; // css file path when Mode.FILE, host path when
                             // Mode.STRING
  private final Mode mode;

  // Below only used when checking css strings
  private final String value; // css string
  private int line; // where css string occurs in host
  private final boolean isStyleAttribute;

  private enum Mode
  {
    FILE,
    STRING
  }

  /**
   * Constructor for CSS files.
   */
  public CSSChecker(ValidationContext context)
  {
    this(context, Mode.FILE, null, -1, false);
  }

  public CSSChecker(ValidationContext context, String value, int line, boolean isStyleAttribute)
  {
    this(context, Mode.STRING, value, line, isStyleAttribute);
  }

  /**
   * Constructor for CSS strings (html style attributes and elements) .
   */
  private CSSChecker(ValidationContext context, Mode mode, String value, int line,
      boolean isStyleAttribute)
  {
    this.context = context;
    this.report = context.report;
    this.path = context.path;
    this.mode = mode;
    this.value = value;
    this.line = line;
    this.isStyleAttribute = isStyleAttribute;
  }

  public void runChecks()
  {
    CssSource source = null;

    try
    {
      if (this.mode == Mode.FILE && !context.ocf.get().hasEntry(path))
      {
        report.message(MessageId.RSC_001, EPUBLocation.create(context.ocf.get().getName()),
            path);
        return;
      }

      CSSHandler handler = new CSSHandler(path, context.xrefChecker.orNull(), report,
          context.version);
      if (this.mode == Mode.STRING && this.line > -1)
      {
        handler.setStartingLineNumber(this.line);
      }

      source = getCssSource();
      parseItem(source, handler);
      handler.setStartingLineNumber(-1);
      this.line = -1;
    } catch (Exception e)
    {
      report.message(MessageId.PKG_008, EPUBLocation.create(path), e.getMessage());
    } finally
    {
      if (source != null)
      {
        try
        {
          InputStream iStream = source.getInputStream();
          if (iStream != null)
          {
            iStream.close();
          }
        } catch (IOException ignored)
        {
          // eat it
        }
      }
    }
  }

  CssSource getCssSource()
    throws IOException
  {
    CssSource source = null;
    if (this.mode == Mode.FILE)
    {
      source = new CssSource(this.path, context.resourceProvider.getInputStream(this.path));
      String charset;
      if (source.getInputStream().getBomCharset().isPresent())
      {
        charset = source.getInputStream().getBomCharset().get().toLowerCase(Locale.ROOT);
        if (!charset.equals("utf-8") && !charset.startsWith("utf-16"))
        {
          report.message(MessageId.CSS_004, EPUBLocation.create(path), charset);
        }
      }
      if (source.getInputStream().getCssCharset().isPresent())
      {
        charset = source.getInputStream().getCssCharset().get().toLowerCase(Locale.ROOT);
        if (!charset.equals("utf-8") && !charset.startsWith("utf-16"))
        {
          report.message(MessageId.CSS_003, EPUBLocation.create(path, ""), charset);
        }
      }
    }
    return source;
  }

  void parseItem(CssSource source, CSSHandler handler)
    throws IOException,
    CssExceptions.CssException
  {
    if (!isStyleAttribute)
    {
      if (this.mode == Mode.FILE)
      {
        new CssParser().parse(source, handler, handler);
      }
      else
      {
        new CssParser().parse(new StringReader(this.value), this.path, handler, handler);
      }
    }
    else
    {
      new CssParser()
          .parseStyleAttribute(new StringReader(this.value), this.path, handler, handler);
    }
  }
}
