package org.hl7.fhir.validation;

/*
  Copyright (c) 2011+, HL7, Inc.
  All rights reserved.
  
  Redistribution and use in source and binary forms, with or without modification, 
  are permitted provided that the following conditions are met:
    
   * Redistributions of source code must retain the above copyright notice, this 
     list of conditions and the following disclaimer.
   * Redistributions in binary form must reproduce the above copyright notice, 
     this list of conditions and the following disclaimer in the documentation 
     and/or other materials provided with the distribution.
   * Neither the name of HL7 nor the names of its contributors may be used to 
     endorse or promote products derived from this software without specific 
     prior written permission.
  
  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND 
  ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 
  WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 
  IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, 
  INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 
  NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR 
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  WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 
  ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 
  POSSIBILITY OF SUCH DAMAGE.
  
 */



import java.io.ByteArrayOutputStream;
import java.io.IOException;

import javax.annotation.Nonnull;

import org.hl7.fhir.convertors.advisors.impl.BaseAdvisor_10_50;
import org.hl7.fhir.convertors.factory.VersionConvertorFactory_10_50;
import org.hl7.fhir.convertors.factory.VersionConvertorFactory_14_50;
import org.hl7.fhir.convertors.factory.VersionConvertorFactory_30_50;
import org.hl7.fhir.convertors.factory.VersionConvertorFactory_40_50;
import org.hl7.fhir.exceptions.FHIRException;

/**
 * This class wraps up the validation and conversion infrastructure
 * so it can be hosted inside a native server
 * 
 * workflow is pretty simple:
 *  - create a DelphiLibraryHost, provide with path to library and tx server to use
 *    (tx server is usually the host server)
 *  - any structure definitions, value sets, code systems changes on the server get sent to tp seeResource or dropResource
 *  - server wants to validate a resource, it calls validateResource and gets an operation outcome back
 *  - server wants to convert from R4 to something else, it calls convertResource  
 *  - server wants to convert to R4 from something else, it calls unConvertResource  
 *  
 * threading: todo: this class should be thread safe
 *  
 * note: this is a solution that uses lots of RAM...  
 */

import org.hl7.fhir.r5.elementmodel.Manager.FhirFormat;
import org.hl7.fhir.r5.formats.JsonParser;
import org.hl7.fhir.r5.formats.XmlParser;
import org.hl7.fhir.r5.model.CodeSystem;
import org.hl7.fhir.r5.model.OperationOutcome;
import org.hl7.fhir.r5.model.Resource;
import org.hl7.fhir.r5.model.ValueSet;
import org.hl7.fhir.r5.utils.validation.constants.BestPracticeWarningLevel;
import org.hl7.fhir.r5.utils.validation.constants.CheckDisplayOption;
import org.hl7.fhir.r5.utils.validation.constants.IdStatus;
import org.hl7.fhir.utilities.FhirPublication;
import org.hl7.fhir.utilities.Utilities;
import org.hl7.fhir.utilities.VersionUtilities;

import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import com.google.gson.JsonObject;

/**
 * This class allows you to host the java validator in another service, and use the services it has in a wider context. The way it works is 

- put the jar in your class path
- Find the class org.hl7.fhir.validation.NativeHostServices 
- call init(path) where path refers to one of the definitions files from the main build (e.g. definitions.xml.zip) - required, do only once, do before anything else
- call load(path) where path refers to the igpack.zip produced by the ig publisher (do this once for each IG you care about)
- call connectToTxSvc(url) where the url is your terminology service of choice (can be http://tx.fhir.org/r4 or /r3)

now the jar is ready for action. There's 3 functions you can call (all are thread safe):
- validate - given a resource, validate it against all known rules
- convert - given a resource in a different version convert it to this version (if possible)
- unconvert - given a resource, convert it to a different version (if possible)


also, call "status" to get a json object that describes the internals of the jar (e.g. for server status)


The interface is optimised for JNI. 
 * @author Grahame Grieve
 *
 */
public class NativeHostServices {
  
  private class NH_10_50_Advisor extends BaseAdvisor_10_50 {
    @Override
    public void handleCodeSystem(@Nonnull CodeSystem tgtcs, @Nonnull ValueSet source) throws FHIRException {}

    @Override
    public CodeSystem getCodeSystem(@Nonnull ValueSet src) throws FHIRException {
      throw new FHIRException("Code systems cannot be handled at this time"); // what to do? need thread local storage? 
    }
  }

  private ValidationEngine validator;
  private IgLoader igLoader;
  private int validationCount = 0;
  private int resourceCount = 0;
  private int convertCount = 0;
  private int unConvertCount = 0;
  private int exceptionCount = 0;
  private String lastException = null;  
  private Object lock = new Object();

  private final BaseAdvisor_10_50 conv_10_50_advisor = new NH_10_50_Advisor();

  /**
   * Create an instance of the service
   */
  public NativeHostServices()  {
    super();
  } 

  /**
   * Initialize the service and prepare it for use
   * 
   * @param pack - the filename of a pack from the main build - either definitions.xml.zip, definitions.json.zip, or igpack.zip 
   * @throws Exception
   */
  public void init(String pack) throws Exception {
    validator = new ValidationEngine.ValidationEngineBuilder().fromSource(pack);
    validator.getContext().setAllowLoadingDuplicates(true);
    igLoader = new IgLoader(validator.getPcm(), validator.getContext(), validator.getVersion(), validator.isDebug());
  }

  /** 
   * Load an IG so that the validator knows all about it.
   * 
   * @param pack - the filename (or URL) of a validator.pack produced by the IGPublisher
   * 
   * @throws Exception
   */
  public void load(String pack) throws Exception {
    igLoader.loadIg(validator.getIgs(), validator.getBinaries(), pack, false);
  }

  /** 
   * Set up the validator with a terminology service 
   * 
   * @param txServer - the URL of the terminology service (http://tx.fhir.org/r4 default)
   * @throws Exception
   */
  public void connectToTxSvc(String txServer, String log) throws Exception {
    validator.connectToTSServer(txServer, log, FhirPublication.R5);
  }

  /**
   * Set up the validator with a terminology service
   *
   * @param txServer - the URL of the terminology service (http://tx.fhir.org/r4 default)
   * @throws Exception
   */
  public void connectToTxSvc(String txServer, String log, String txCache) throws Exception {
    validator.connectToTSServer(txServer, log, txCache, FhirPublication.R5);
  }

  /**
   * get back a JSON object with information about the process.
   * @return
   */
  public String status() {
    JsonObject json = new JsonObject();
    json.addProperty("custom-resource-count", resourceCount);
    validator.getContext().reportStatus(json);
    json.addProperty("validation-count", validationCount);
    json.addProperty("convert-count", convertCount);
    json.addProperty("unconvert-count", unConvertCount);
    json.addProperty("exception-count", exceptionCount);
    synchronized (lock) {
      json.addProperty("last-exception", lastException);      
    }

    json.addProperty("mem-max", Runtime.getRuntime().maxMemory() / (1024*1024));
    json.addProperty("mem-total", Runtime.getRuntime().totalMemory() / (1024*1024));
    json.addProperty("mem-free", Runtime.getRuntime().freeMemory() / (1024*1024));
    json.addProperty("mem-used", (Runtime.getRuntime().totalMemory() - Runtime.getRuntime().freeMemory()) / (1024*1024));

    Gson gson = new GsonBuilder().create();
    return gson.toJson(json);
  }

  /**
   * Call when the host process encounters one of the following:
   *  - (for validation):
   *    - profile
   *    - extension definition
   *    - value set
   *    - code system
   * 
   *  - (for conversion):
   *    - structure map 
   *    - concept map
   *  
   * @param source
   * @throws Exception
   */
  public void seeResource(byte[] source, FhirFormat fmt) throws Exception {
    try {
      Resource r;
      if (fmt == FhirFormat.JSON) {
        r = new JsonParser().parse(source);
      } else if (fmt == FhirFormat.JSON) {
        r = new XmlParser().parse(source);
      } else {
        throw new Exception("Unsupported format "+fmt.name());
      }
      validator.seeResource(r);
      resourceCount++;
    } catch (Exception e) {
      exceptionCount++;

      synchronized (lock) {
        lastException = e.getMessage();
      }
      throw e;
    }
  }

  /**
   * forget a resource that was previously seen (using @seeResource)
   * 
   * @param type - the resource type
   * @param id - the resource id 
   * 
   * @throws Exception
   */
  public void dropResource(String type, String id) throws Exception  {
    try {
      validator.dropResource(type, id);
      resourceCount--;
    } catch (Exception e) {
      exceptionCount++;
      synchronized (lock) {
        lastException = e.getMessage();
      }
      throw e;
    }
  }

  /**
   * Validate a resource. 
   * 
   * Possible options:
   *   - id-optional : no resource id is required (default) 
   *   - id-required : a resource id is required
   *   - id-prohibited : no resource id is allowed
   *   - any-extensions : allow extensions other than those defined by the encountered structure definitions
   *   - bp-ignore : ignore best practice recommendations (default)
   *   - bp-hint : treat best practice recommendations as a hint
   *   - bp-warning : treat best practice recommendations as a warning 
   *   - bp-error : treat best practice recommendations as an error
   *   - display-ignore : ignore Coding.display and do not validate it (default)
   *   - display-check : check Coding.display - must be correct
   *   - display-case-space : check Coding.display but allow case and whitespace variation
   *   - display-case : check Coding.display but allow case variation
   *   - display-space : check Coding.display but allow whitespace variation
   *    
   * @param location - a text description of the context of validation (for human consumers to help locate the problem - echoed into error messages)
   * @param source - the bytes to validate
   * @param cntType - the format of the content. one of XML, JSON, TURTLE
   * @param options - a list of space separated options 
   * @return
   * @throws Exception
   */
  public byte[] validateResource(String location, byte[] source, String cntType, String options) throws Exception {
    try {
      IdStatus resourceIdRule = IdStatus.OPTIONAL;
      boolean anyExtensionsAllowed = true;
      BestPracticeWarningLevel bpWarnings = BestPracticeWarningLevel.Ignore;
      CheckDisplayOption displayOption = CheckDisplayOption.Ignore;
      for (String s : options.split(" ")) {
        if ("id-optional".equalsIgnoreCase(s))
          resourceIdRule = IdStatus.OPTIONAL;
        else if ("id-required".equalsIgnoreCase(s))
          resourceIdRule = IdStatus.REQUIRED;
        else if ("id-prohibited".equalsIgnoreCase(s))
          resourceIdRule = IdStatus.PROHIBITED;
        else if ("any-extensions".equalsIgnoreCase(s))
          anyExtensionsAllowed = true; // This is already the default
        else if ("strict-extensions".equalsIgnoreCase(s))
          anyExtensionsAllowed = false;
        else if ("bp-ignore".equalsIgnoreCase(s))
          bpWarnings = BestPracticeWarningLevel.Ignore;
        else if ("bp-hint".equalsIgnoreCase(s))
          bpWarnings = BestPracticeWarningLevel.Hint;
        else if ("bp-warning".equalsIgnoreCase(s))
          bpWarnings = BestPracticeWarningLevel.Warning;
        else if ("bp-error".equalsIgnoreCase(s))
          bpWarnings = BestPracticeWarningLevel.Error;
        else if ("display-ignore".equalsIgnoreCase(s))
          displayOption = CheckDisplayOption.Ignore;
        else if ("display-check".equalsIgnoreCase(s))
          displayOption = CheckDisplayOption.Check;
        else if ("display-case-space".equalsIgnoreCase(s))
          displayOption = CheckDisplayOption.CheckCaseAndSpace;
        else if ("display-case".equalsIgnoreCase(s))
          displayOption = CheckDisplayOption.CheckCase;
        else if ("display-space".equalsIgnoreCase(s))
          displayOption = CheckDisplayOption.CheckSpace;
        else if (!Utilities.noString(s))
          throw new Exception("Unknown option "+s);
      }

      OperationOutcome oo = validator.validate(location, source, FhirFormat.valueOf(cntType), null, resourceIdRule, anyExtensionsAllowed, bpWarnings, displayOption);
      ByteArrayOutputStream bs = new ByteArrayOutputStream();
      new XmlParser().compose(bs, oo);
      validationCount++;
      return bs.toByteArray();
    } catch (Exception e) {
      exceptionCount++;
      synchronized (lock) {
        lastException = e.getMessage();
      }
      throw e;
    }
  }

  /**
   * Convert a resource to R4 from the specified version
   * 
   * @param r - the source of the resource to convert from
   * @param fmt  - the format of the content. one of XML, JSON, TURTLE
   * @param version - the version of the content. one of r2, r3
   * @return - the converted resource (or an exception if can't be converted)
   * @throws FHIRException
   * @throws IOException
   */
  public byte[] convertResource(byte[] r, String fmt, String version) throws FHIRException, IOException  {
    try {
      if (VersionUtilities.isR3Ver(version)) {
        org.hl7.fhir.dstu3.formats.ParserBase p3 = org.hl7.fhir.dstu3.formats.FormatUtilities.makeParser(fmt);
        org.hl7.fhir.dstu3.model.Resource res3 = p3.parse(r);
        Resource res4 = VersionConvertorFactory_30_50.convertResource(res3);
        org.hl7.fhir.r5.formats.ParserBase p4 = org.hl7.fhir.r5.formats.FormatUtilities.makeParser(fmt);
        convertCount++;
        return p4.composeBytes(res4);
      } else if (VersionUtilities.isR2Ver(version)) {
        org.hl7.fhir.dstu2.formats.ParserBase p2 = org.hl7.fhir.dstu2.formats.FormatUtilities.makeParser(fmt);
        org.hl7.fhir.dstu2.model.Resource res2 = p2.parse(r);
        Resource res4 = VersionConvertorFactory_10_50.convertResource(res2, conv_10_50_advisor);
        org.hl7.fhir.r5.formats.ParserBase p4 = org.hl7.fhir.r5.formats.FormatUtilities.makeParser(fmt);
        convertCount++;
        return p4.composeBytes(res4);
      } else if (VersionUtilities.isR2BVer(version)) {
        org.hl7.fhir.dstu2016may.formats.ParserBase p2 = org.hl7.fhir.dstu2016may.formats.FormatUtilities.makeParser(fmt);
        org.hl7.fhir.dstu2016may.model.Resource res2 = p2.parse(r);
        Resource res4 = VersionConvertorFactory_14_50.convertResource(res2);
        org.hl7.fhir.r5.formats.ParserBase p4 = org.hl7.fhir.r5.formats.FormatUtilities.makeParser(fmt);
        convertCount++;
        return p4.composeBytes(res4);
      } else if (VersionUtilities.isR4Ver(version)) {
        org.hl7.fhir.r4.formats.ParserBase p2 = org.hl7.fhir.r4.formats.FormatUtilities.makeParser(fmt);
        org.hl7.fhir.r4.model.Resource res2 = p2.parse(r);
        Resource res4 = VersionConvertorFactory_40_50.convertResource(res2);
        org.hl7.fhir.r5.formats.ParserBase p4 = org.hl7.fhir.r5.formats.FormatUtilities.makeParser(fmt);
        convertCount++;
        return p4.composeBytes(res4);
      } else
        throw new FHIRException("Unsupported version "+version);
    } catch (Exception e) {
      exceptionCount++;
      synchronized (lock) {
        lastException = e.getMessage();
      }
      throw e;
    }
  }

  /**
   * Convert a resource from R4 to the specified version
   * 
   * @param r - the source of the resource to convert from
   * @param fmt  - the format of the content. one of XML, JSON, TURTLE
   * @param version - the version to convert to. one of r2, r3
   * @return - the converted resource (or an exception if can't be converted)
   * @throws FHIRException
   * @throws IOException
   */
  public byte[] unConvertResource(byte[] r, String fmt, String version) throws FHIRException, IOException  {
    try {
      if ("3.0".equals(version) || "3.0.1".equals(version) || "r3".equals(version)) {
        org.hl7.fhir.r5.formats.ParserBase p4 = org.hl7.fhir.r5.formats.FormatUtilities.makeParser(fmt);
        org.hl7.fhir.r5.model.Resource res4 = p4.parse(r);
        org.hl7.fhir.dstu3.model.Resource res3 = VersionConvertorFactory_30_50.convertResource(res4);
        org.hl7.fhir.dstu3.formats.ParserBase p3 = org.hl7.fhir.dstu3.formats.FormatUtilities.makeParser(fmt);
        unConvertCount++;
        return p3.composeBytes(res3);
      } else if ("1.0".equals(version) || "1.0.2".equals(version) || "r2".equals(version)) {
        org.hl7.fhir.r5.formats.ParserBase p4 = org.hl7.fhir.r5.formats.FormatUtilities.makeParser(fmt);
        org.hl7.fhir.r5.model.Resource res4 = p4.parse(r);
        org.hl7.fhir.dstu2.model.Resource res2 = VersionConvertorFactory_10_50.convertResource(res4, conv_10_50_advisor);
        org.hl7.fhir.dstu2.formats.ParserBase p2 = org.hl7.fhir.dstu2.formats.FormatUtilities.makeParser(fmt);
        unConvertCount++;
        return p2.composeBytes(res2);
      } else if ("1.4".equals(version) || "1.4.0".equals(version)) {
        org.hl7.fhir.r5.formats.ParserBase p4 = org.hl7.fhir.r5.formats.FormatUtilities.makeParser(fmt);
        org.hl7.fhir.r5.model.Resource res4 = p4.parse(r);
        org.hl7.fhir.dstu2016may.model.Resource res2 = VersionConvertorFactory_14_50.convertResource(res4);
        org.hl7.fhir.dstu2016may.formats.ParserBase p2 = org.hl7.fhir.dstu2016may.formats.FormatUtilities.makeParser(fmt);
        unConvertCount++;
        return p2.composeBytes(res2);
      } else
        throw new FHIRException("Unsupported version "+version);
    } catch (Exception e) {
      exceptionCount++;
      synchronized (lock) {
        lastException = e.getMessage();
      }
      throw e;
    }
  }


}