/**
    * Copyright (C) 2014-2015 Philip Helger (www.helger.com)
    * philip[at]helger[dot]com
    *
    * Licensed under the Apache License, Version 2.0 (the "License");
    * you may not use this file except in compliance with the License.
    * You may obtain a copy of the License at
    *
    *         http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  package com.helger.schematron.pure.preprocess;
  
  import java.util.ArrayList;
  import java.util.List;
  import java.util.Map;
  
  import javax.annotation.Nonnull;
  import javax.annotation.Nullable;
  import javax.annotation.concurrent.NotThreadSafe;
  
  import com.helger.commons.ValueEnforcer;
  import com.helger.commons.annotation.ReturnsMutableCopy;
  import com.helger.commons.string.ToStringGenerator;
  import com.helger.schematron.pure.binding.IPSQueryBinding;
  import com.helger.schematron.pure.model.IPSElement;
  import com.helger.schematron.pure.model.PSActive;
  import com.helger.schematron.pure.model.PSAssertReport;
  import com.helger.schematron.pure.model.PSDiagnostic;
  import com.helger.schematron.pure.model.PSDiagnostics;
  import com.helger.schematron.pure.model.PSDir;
  import com.helger.schematron.pure.model.PSEmph;
  import com.helger.schematron.pure.model.PSExtends;
  import com.helger.schematron.pure.model.PSLet;
  import com.helger.schematron.pure.model.PSNS;
  import com.helger.schematron.pure.model.PSName;
  import com.helger.schematron.pure.model.PSPattern;
  import com.helger.schematron.pure.model.PSPhase;
  import com.helger.schematron.pure.model.PSRule;
  import com.helger.schematron.pure.model.PSSchema;
  import com.helger.schematron.pure.model.PSSpan;
  import com.helger.schematron.pure.model.PSValueOf;
  
  /**
   * This is the pre-processor class for pure Schematron. It converts an existing
   * schema to the minimal syntax (by default) but allows for a certain degree of
   * customization by keeping certain elements in the resulting schema. The actual
   * query binding is used, so that report test expressions can be converted to
   * assertions, and to replace the content of <param> elements into actual
   * values.
   *
   * @author Philip Helger
   */
  @NotThreadSafe
  public class PSPreprocessor
  {
    public static final boolean DEFAULT_KEEP_TITLES = false;
    public static final boolean DEFAULT_KEEP_DIAGNOSTICS = false;
    public static final boolean DEFAULT_KEEP_REPORTS = false;
    public static final boolean DEFAULT_KEEP_EMPTY_PATTERNS = true;
    public static final boolean DEFAULT_KEEP_EMPTY_SCHEMA = true;
  
    private final IPSQueryBinding m_aQueryBinding;
    private boolean m_bKeepTitles = DEFAULT_KEEP_TITLES;
    private boolean m_bKeepDiagnostics = DEFAULT_KEEP_DIAGNOSTICS;
    private boolean m_bKeepReports = DEFAULT_KEEP_REPORTS;
    private boolean m_bKeepEmptyPatterns = DEFAULT_KEEP_EMPTY_PATTERNS;
    private boolean m_bKeepEmptySchema = DEFAULT_KEEP_EMPTY_SCHEMA;
  
    public PSPreprocessor (@Nonnull final IPSQueryBinding aQueryBinding)
    {
      m_aQueryBinding = ValueEnforcer.notNull (aQueryBinding, "QueryBinding");
    }
  
    /**
     * @return The query binding to be used. Never <code>null</code>!
     */
    @Nonnull
    public IPSQueryBinding getQueryBinding ()
    {
      return m_aQueryBinding;
    }
  
    /**
     * @return <code>true</code> if &lt;title&gt;-elements should be kept. Default
     *         is {@value #DEFAULT_KEEP_TITLES}.
     */
    public boolean isKeepTitles ()
    {
      return m_bKeepTitles;
    }
  
    @Nonnull
    public PSPreprocessor setKeepTitles (final boolean bKeepTitles)
   {
     m_bKeepTitles = bKeepTitles;
     return this;
   }
 
   /**
    * @return <code>true</code> if &lt;diagnostics&gt;-elements should be kept.
    *         Default is {@value #DEFAULT_KEEP_DIAGNOSTICS}.
    */
   public boolean isKeepDiagnostics ()
   {
     return m_bKeepDiagnostics;
   }
 
   @Nonnull
   public PSPreprocessor setKeepDiagnostics (final boolean bKeepDiagnostics)
   {
     m_bKeepDiagnostics = bKeepDiagnostics;
     return this;
   }
 
   /**
    * @return <code>true</code> if &lt;report&gt;-elements should be kept.
    *         Default is {@value #DEFAULT_KEEP_REPORTS}.
    */
   public boolean isKeepReports ()
   {
     return m_bKeepReports;
   }
 
   @Nonnull
   public PSPreprocessor setKeepReports (final boolean bKeepReports)
   {
     m_bKeepReports = bKeepReports;
     return this;
   }
 
   /**
    * @return <code>true</code> if &lt;pattern&gt;-elements without a rule should
    *         be kept. Default is {@value #DEFAULT_KEEP_EMPTY_PATTERNS}.
    */
   public boolean isKeepEmptyPatterns ()
   {
     return m_bKeepEmptyPatterns;
   }
 
   @Nonnull
   public PSPreprocessor setKeepEmptyPatterns (final boolean bKeepEmptyPatterns)
   {
     m_bKeepEmptyPatterns = bKeepEmptyPatterns;
     return this;
   }
 
   /**
    * @return <code>true</code> if &lt;schema&gt;-elements without a pattern
    *         should be kept. Default is {@value #DEFAULT_KEEP_EMPTY_SCHEMA}.
    */
   public boolean isKeepEmptySchema ()
   {
     return m_bKeepEmptySchema;
   }
 
   /**
    * Should schema objects without a pattern be kept? It makes only sense to set
    * it to <code>false</code> if {@link #setKeepEmptyPatterns(boolean)} is also
    * set to false, because otherwise patterns without rules are kept.
    *
    * @param bKeepEmptySchema
    *        <code>true</code> to keep them, <code>false</code> to discard them.
    * @return this
    */
   @Nonnull
   public PSPreprocessor setKeepEmptySchema (final boolean bKeepEmptySchema)
   {
     m_bKeepEmptySchema = bKeepEmptySchema;
     return this;
   }
 
   @Nonnull
   private static PSPhase _getPreprocessedPhase (@Nonnull final PSPhase aPhase,
                                                 @Nonnull final PreprocessorIDPool aIDPool) throws SchematronPreprocessException
   {
     final PSPhase ret = new PSPhase ();
     ret.setID (aIDPool.getUniqueID (aPhase.getID ()));
     ret.setRich (aPhase.getRichClone ());
     if (aPhase.hasAnyInclude ())
       throw new SchematronPreprocessException ("Cannot preprocess <phase> with an <include>");
     for (final IPSElement aElement : aPhase.getAllContentElements ())
     {
       if (aElement instanceof PSActive)
         ret.addActive (((PSActive) aElement).getClone ());
       else
         if (aElement instanceof PSLet)
           ret.addLet (((PSLet) aElement).getClone ());
       // ps are ignored
     }
     ret.addForeignElements (aPhase.getAllForeignElements ());
     ret.addForeignAttributes (aPhase.getAllForeignAttributes ());
     return ret;
   }
 
   /**
    * Resolve all &lt;extends&gt; elements. This method calls itself recursively
    * until all extends elements are resolved.
    *
    * @param aRuleContent
    *        A list consisting of {@link PSAssertReport} and {@link PSExtends}
    *        objects. Never <code>null</code>.
    * @param aLookup
    *        The rule lookup object
    * @return List of assert/report elements. Never <code>null</code>.
    * @throws SchematronPreprocessException
    *         If the base rule of an extends object could not be resolved.
    */
   @Nonnull
   @ReturnsMutableCopy
   private static List <PSAssertReport> _getResolvedExtends (@Nonnull final List <IPSElement> aRuleContent,
                                                             @Nonnull final PreprocessorLookup aLookup) throws SchematronPreprocessException
   {
     final List <PSAssertReport> ret = new ArrayList <PSAssertReport> ();
     for (final IPSElement aElement : aRuleContent)
     {
       if (aElement instanceof PSAssertReport)
         ret.add ((PSAssertReport) aElement);
       else
       {
         final PSExtends aExtends = (PSExtends) aElement;
         final String sRuleID = aExtends.getRule ();
         final PSRule aBaseRule = aLookup.getAbstractRuleOfID (sRuleID);
         if (aBaseRule == null)
           throw new SchematronPreprocessException ("Failed to resolve rule ID '" +
                                                    sRuleID +
                                                    "' in extends statement. Available rules are: " +
                                                    aLookup.getAllAbstractRuleIDs ());
         // Recursively resolve the extends of the base rule
         ret.addAll (_getResolvedExtends (aBaseRule.getAllContentElements (), aLookup));
       }
     }
     return ret;
   }
 
   @Nonnull
   private PSAssertReport _getPreprocessedAssert (@Nonnull final PSAssertReport aAssertReport,
                                                  @Nonnull final PreprocessorIDPool aIDPool,
                                                  @Nullable final Map <String, String> aParamValueMap)
   {
     String sTest = aAssertReport.getTest ();
     if (aAssertReport.isReport () && !m_bKeepReports)
     {
       // Negate the expression!
       sTest = m_aQueryBinding.getNegatedTestExpression (sTest);
     }
 
     // Keep report or make it always an assert
     final PSAssertReport ret = new PSAssertReport (m_bKeepReports ? aAssertReport.isAssert () : true);
     ret.setTest (m_aQueryBinding.getWithParamTextsReplaced (sTest, aParamValueMap));
     ret.setFlag (aAssertReport.getFlag ());
     ret.setID (aIDPool.getUniqueID (aAssertReport.getID ()));
     if (m_bKeepDiagnostics)
       ret.setDiagnostics (aAssertReport.getAllDiagnostics ());
     ret.setRich (aAssertReport.getRichClone ());
     ret.setLinkable (aAssertReport.getLinkableClone ());
     for (final Object aContent : aAssertReport.getAllContentElements ())
     {
       if (aContent instanceof String)
         ret.addText ((String) aContent);
       else
         if (aContent instanceof PSName)
           ret.addName (((PSName) aContent).getClone ());
         else
           if (aContent instanceof PSValueOf)
           {
             final PSValueOf aValueOf = ((PSValueOf) aContent).getClone ();
             aValueOf.setSelect (m_aQueryBinding.getWithParamTextsReplaced (aValueOf.getSelect (), aParamValueMap));
             ret.addValueOf (aValueOf);
           }
           else
             if (aContent instanceof PSEmph)
               ret.addEmph (((PSEmph) aContent).getClone ());
             else
               if (aContent instanceof PSDir)
                 ret.addDir (((PSDir) aContent).getClone ());
               else
                 if (aContent instanceof PSSpan)
                   ret.addSpan (((PSSpan) aContent).getClone ());
     }
     ret.addForeignElements (aAssertReport.getAllForeignElements ());
     ret.addForeignAttributes (aAssertReport.getAllForeignAttributes ());
     return ret;
   }
 
   @Nullable
   private PSRule _getPreprocessedRule (@Nonnull final PSRule aRule,
                                        @Nonnull final PreprocessorLookup aLookup,
                                        @Nonnull final PreprocessorIDPool aIDPool,
                                        @Nullable final Map <String, String> aParamValueMap) throws SchematronPreprocessException
   {
     if (aRule.isAbstract ())
     {
       // Will be inlined
       return null;
     }
 
     final PSRule ret = new PSRule ();
     ret.setFlag (aRule.getFlag ());
     ret.setRich (aRule.getRichClone ());
     ret.setLinkable (aRule.getLinkableClone ());
     // abstract is always false
     ret.setContext (m_aQueryBinding.getWithParamTextsReplaced (aRule.getContext (), aParamValueMap));
     ret.setID (aIDPool.getUniqueID (aRule.getID ()));
     if (aRule.hasAnyInclude ())
       throw new SchematronPreprocessException ("Cannot preprocess <rule> with an <include>");
     for (final PSLet aLet : aRule.getAllLets ())
       ret.addLet (aLet.getClone ());
     for (final PSAssertReport aAssertReport : _getResolvedExtends (aRule.getAllContentElements (), aLookup))
       ret.addAssertReport (_getPreprocessedAssert (aAssertReport, aIDPool, aParamValueMap));
     ret.addForeignElements (aRule.getAllForeignElements ());
     ret.addForeignAttributes (aRule.getAllForeignAttributes ());
     return ret;
   }
 
   @Nullable
   private PSPattern _getPreprocessedPattern (@Nonnull final PSPattern aPattern,
                                              @Nonnull final PreprocessorLookup aLookup,
                                              @Nonnull final PreprocessorIDPool aIDPool) throws SchematronPreprocessException
   {
     if (aPattern.isAbstract ())
     {
       // Will be inlined
       return null;
     }
 
     final PSPattern ret = new PSPattern ();
     // abstract always false
     // is-a must be resolved
     ret.setID (aIDPool.getUniqueID (aPattern.getID ()));
     ret.setRich (aPattern.getRichClone ());
     if (aPattern.hasAnyInclude ())
       throw new SchematronPreprocessException ("Cannot preprocess <pattern> with an <include>");
     if (m_bKeepTitles && aPattern.hasTitle ())
       ret.setTitle (aPattern.getTitle ().getClone ());
 
     final String sIsA = aPattern.getIsA ();
     if (sIsA != null)
     {
       final PSPattern aBasePattern = aLookup.getAbstractPatternOfID (sIsA);
       if (aBasePattern == null)
         throw new SchematronPreprocessException ("Failed to resolve the pattern denoted by is-a='" + sIsA + "'");
 
       if (!ret.hasID ())
         ret.setID (aIDPool.getUniqueID (aBasePattern.getID ()));
       if (!ret.hasRich ())
         ret.setRich (aBasePattern.getRichClone ());
 
       // get the string replacements
       final Map <String, String> aParamValueMap = m_aQueryBinding.getStringReplacementMap (aPattern.getAllParams ());
 
       for (final IPSElement aElement : aBasePattern.getAllContentElements ())
       {
         if (aElement instanceof PSLet)
           ret.addLet (((PSLet) aElement).getClone ());
         else
           if (aElement instanceof PSRule)
           {
             final PSRule aMinifiedRule = _getPreprocessedRule ((PSRule) aElement, aLookup, aIDPool, aParamValueMap);
             if (aMinifiedRule != null)
               ret.addRule (aMinifiedRule);
           }
         // params must have be resolved
         // ps are ignored
       }
     }
     else
     {
       for (final IPSElement aElement : aPattern.getAllContentElements ())
       {
         if (aElement instanceof PSLet)
           ret.addLet (((PSLet) aElement).getClone ());
         else
           if (aElement instanceof PSRule)
           {
             final PSRule aMinifiedRule = _getPreprocessedRule ((PSRule) aElement, aLookup, aIDPool, null);
             if (aMinifiedRule != null)
               ret.addRule (aMinifiedRule);
           }
         // params must be resolved
         // ps are ignored
       }
     }
     ret.addForeignElements (aPattern.getAllForeignElements ());
     ret.addForeignAttributes (aPattern.getAllForeignAttributes ());
     return ret;
   }
 
   @Nonnull
   private static PSDiagnostics _getPreprocessedDiagnostics (@Nonnull final PSDiagnostics aDiagnostics) throws SchematronPreprocessException
   {
     final PSDiagnostics ret = new PSDiagnostics ();
     if (aDiagnostics.hasAnyInclude ())
       throw new SchematronPreprocessException ("Cannot preprocess <diagnostics> with an <include>");
     for (final PSDiagnostic aDiagnostic : aDiagnostics.getAllDiagnostics ())
       ret.addDiagnostic (aDiagnostic.getClone ());
     ret.addForeignElements (aDiagnostics.getAllForeignElements ());
     ret.addForeignAttributes (aDiagnostics.getAllForeignAttributes ());
     return ret;
   }
 
   /**
    * Convert the passed schema to a minimal schema.
    *
    * @param aSchema
    *        The schema to be made minimal. May not be <code>null</code>
    * @return The original schema object, if it is already minimal - a minimal
    *         copy otherwise! May be <code>null</code> if the original schema is
    *         not yet minimal and {@link #isKeepEmptySchema()} is set to
    *         <code>false</code>.
    * @throws SchematronPreprocessException
    *         In case a preprocessing error occurs
    */
   @Nullable
   public PSSchema getAsMinimalSchema (@Nonnull final PSSchema aSchema) throws SchematronPreprocessException
   {
     ValueEnforcer.notNull (aSchema, "Schema");
 
     // Anything to do?
     if (aSchema.isMinimal ())
       return aSchema;
 
     return getForcedPreprocessedSchema (aSchema);
   }
 
   /**
    * Convert the passed schema to a pre-processed schema.
    *
    * @param aSchema
    *        The schema to pre-process. May not be <code>null</code>
    * @return The original schema object, if it is already pre-processed - a
    *         pre-processed copy otherwise! May be <code>null</code> if the
    *         original schema is not yet pre-processed and
    *         {@link #isKeepEmptySchema()} is set to <code>false</code>.
    * @throws SchematronPreprocessException
    *         In case a preprocessing error occurs
    */
   @Nullable
   public PSSchema getAsPreprocessedSchema (@Nonnull final PSSchema aSchema) throws SchematronPreprocessException
   {
     ValueEnforcer.notNull (aSchema, "Schema");
 
     // Anything to do?
     if (aSchema.isPreprocessed ())
       return aSchema;
 
     return getForcedPreprocessedSchema (aSchema);
   }
 
   /**
    * Convert the passed schema to a pre-processed schema independent if it is
    * already minimal or not.
    *
    * @param aSchema
    *        The schema to be made minimal. May not be <code>null</code>
    * @return A minimal copy of the schema. May be <code>null</code> if the
    *         original schema is not yet minimal and {@link #isKeepEmptySchema()}
    *         is set to <code>false</code>.
    * @throws SchematronPreprocessException
    *         In case a preprocessing error occurs
    */
   @Nullable
   public PSSchema getForcedPreprocessedSchema (@Nonnull final PSSchema aSchema) throws SchematronPreprocessException
   {
     ValueEnforcer.notNull (aSchema, "Schema");
 
     final PreprocessorLookup aLookup = new PreprocessorLookup (aSchema);
     final PreprocessorIDPool aIDPool = new PreprocessorIDPool ();
 
     final PSSchema ret = new PSSchema (aSchema.getResource ());
     ret.setID (aIDPool.getUniqueID (aSchema.getID ()));
     ret.setRich (aSchema.getRichClone ());
     ret.setSchemaVersion (aSchema.getSchemaVersion ());
     ret.setDefaultPhase (aSchema.getDefaultPhase ());
     ret.setQueryBinding (aSchema.getQueryBinding ());
     if (m_bKeepTitles && aSchema.hasTitle ())
       ret.setTitle (aSchema.getTitle ().getClone ());
     if (aSchema.hasAnyInclude ())
       throw new SchematronPreprocessException ("Cannot preprocess <schema> with an <include>");
     for (final PSNS aNS : aSchema.getAllNSs ())
       ret.addNS (aNS.getClone ());
     // start ps are skipped
     for (final PSLet aLet : aSchema.getAllLets ())
       ret.addLet (aLet.getClone ());
     for (final PSPhase aPhase : aSchema.getAllPhases ())
       ret.addPhase (_getPreprocessedPhase (aPhase, aIDPool));
     for (final PSPattern aPattern : aSchema.getAllPatterns ())
     {
       final PSPattern aMinifiedPattern = _getPreprocessedPattern (aPattern, aLookup, aIDPool);
       if (aMinifiedPattern != null)
       {
         // Pattern without rules?
         if (aMinifiedPattern.getRuleCount () > 0 || m_bKeepEmptyPatterns)
           ret.addPattern (aMinifiedPattern);
       }
     }
 
     // Schema without patterns?
     if (aSchema.getPatternCount () == 0 && !m_bKeepEmptySchema)
       return null;
 
     // end ps are skipped
     if (m_bKeepDiagnostics && aSchema.hasDiagnostics ())
       ret.setDiagnostics (_getPreprocessedDiagnostics (aSchema.getDiagnostics ()));
     ret.addForeignElements (aSchema.getAllForeignElements ());
     ret.addForeignAttributes (aSchema.getAllForeignAttributes ());
     return ret;
   }
 
   @Override
   public String toString ()
   {
     return new ToStringGenerator (this).append ("queryBinding", m_aQueryBinding)
                                        .append ("keepTitles", m_bKeepTitles)
                                        .append ("keepDiagnostics", m_bKeepDiagnostics)
                                        .append ("keepReports", m_bKeepReports)
                                        .append ("keepEmptyPatterns", m_bKeepEmptyPatterns)
                                        .append ("keepEmptySchema", m_bKeepEmptySchema)
                                        .toString ();
   }
 
   @Nonnull
   public static PSPreprocessor createPreprocessorWithoutInformationLoss (@Nonnull final IPSQueryBinding aQueryBinding)
   {
     final PSPreprocessor aPreprocessor = new PSPreprocessor (aQueryBinding);
 
     // Keep as much of the original information as possible, as it is not our
     // goal to minify the scheme
     aPreprocessor.setKeepReports (true);
     aPreprocessor.setKeepDiagnostics (true);
     aPreprocessor.setKeepTitles (true);
 
     return aPreprocessor;
   }
 }