package org.hl7.fhir.r5.context;

import java.io.FileNotFoundException;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.Comparator;
import java.util.Date;
import java.util.HashSet;

/*
  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 
  PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 
  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.util.List;
import java.util.Locale;
import java.util.Map;
import java.util.Set;

import org.fhir.ucum.UcumService;
import org.hl7.fhir.exceptions.DefinitionException;
import org.hl7.fhir.exceptions.FHIRException;
import org.hl7.fhir.exceptions.TerminologyServiceException;
import org.hl7.fhir.r5.context.IWorkerContext.OIDDefinition;
import org.hl7.fhir.r5.context.IWorkerContext.OIDDefinitionComparer;
import org.hl7.fhir.r5.context.IWorkerContext.ITerminologyOperationDetails;
import org.hl7.fhir.r5.elementmodel.Element;
import org.hl7.fhir.r5.formats.IParser;
import org.hl7.fhir.r5.formats.ParserType;
import org.hl7.fhir.r5.model.CanonicalResource;
import org.hl7.fhir.r5.model.CodeSystem;
import org.hl7.fhir.r5.model.CodeableConcept;
import org.hl7.fhir.r5.model.Coding;
import org.hl7.fhir.r5.model.ConceptMap;
import org.hl7.fhir.r5.model.ElementDefinition.ElementDefinitionBindingComponent;
import org.hl7.fhir.r5.model.NamingSystem;
import org.hl7.fhir.r5.model.OperationOutcome;
import org.hl7.fhir.r5.model.PackageInformation;
import org.hl7.fhir.r5.model.Parameters;
import org.hl7.fhir.r5.model.Resource;
import org.hl7.fhir.r5.model.StructureDefinition;
import org.hl7.fhir.r5.model.StructureMap;
import org.hl7.fhir.r5.model.ValueSet;
import org.hl7.fhir.r5.model.ValueSet.ConceptSetComponent;
import org.hl7.fhir.r5.profilemodel.PEDefinition;
import org.hl7.fhir.r5.profilemodel.PEBuilder.PEElementPropertiesPolicy;
import org.hl7.fhir.r5.profilemodel.PEBuilder;
import org.hl7.fhir.r5.terminologies.expansion.ValueSetExpansionOutcome;
import org.hl7.fhir.r5.terminologies.utilities.CodingValidationRequest;
import org.hl7.fhir.r5.terminologies.utilities.ValidationResult;
import org.hl7.fhir.r5.utils.validation.IResourceValidator;
import org.hl7.fhir.r5.utils.validation.ValidationContextCarrier;
import org.hl7.fhir.utilities.CommaSeparatedStringBuilder;
import org.hl7.fhir.utilities.FhirPublication;
import org.hl7.fhir.utilities.MarkedToMoveToAdjunctPackage;
import org.hl7.fhir.utilities.TimeTracker;
import org.hl7.fhir.utilities.npm.BasePackageCacheManager;
import org.hl7.fhir.utilities.npm.NpmPackage;
import org.hl7.fhir.utilities.validation.ValidationMessage;
import org.hl7.fhir.utilities.validation.ValidationOptions;

import javax.annotation.Nonnull;


/**
 * This is the standard interface used for access to underlying FHIR
 * services through the tools and utilities provided by the reference
 * implementation. 
 * 
 * The functionality it provides is 
 *  - get access to canonical resources,terminology services, and validator
 *    (you can't create a validator directly because it needs access 
 *    to the right context for their information)
 *    
 *  - find resources that the tools need to carry out their tasks
 *  
 *  - provide access to terminology services they need. 
 *    (typically, these terminology service requests are just
 *    passed through to the local implementation's terminology
 *    service)    
 *  
 * @author Grahame
 */

@MarkedToMoveToAdjunctPackage
public interface IWorkerContext {

  public interface ITerminologyOperationDetails {

    public void seeSupplement(CodeSystem supp);
  }
  public class OIDDefinitionComparer implements Comparator<OIDDefinition> {

    @Override
    public int compare(OIDDefinition o1, OIDDefinition o2) {
      if (o1.getUrl().equals(o2.getUrl())) {
        return -o1.getVersion().compareTo(o2.getVersion());        
      } else {
        return o1.getUrl().compareTo(o2.getUrl());
      }
    }
  }

  public class OIDDefinition {
    private String type;
    private String oid;
    private String url;
    private String version;
    private String packageSrc;
    private String status;
    protected OIDDefinition(String type, String oid, String url, String version, String status, String packageSrc) {
      super();
      this.type = type;
      this.oid = oid;
      this.url = url;
      this.version = version == null ? "" : version;
      this.packageSrc = packageSrc;
      this.status = status;
    }
    public String getType() {
      return type;
    }
    public String getOid() {
      return oid;
    }
    public String getUrl() {
      return url;
    }
    public String getVersion() {
      return version;
    }
    public String getStatus() {
      return status;
    }
    public String getPackageSrc() {
      return packageSrc;
    }
    public String summary() {
      return url+(version == null ? "" : "|"+version)+(packageSrc != null ? "("+packageSrc+")" : "");
    }
    public boolean matches(OIDDefinition t) {
      return url.equals(t.url) && version.equals(t.version);
    }
    
  }

  public class OIDSummary {
    private List<OIDDefinition> definitions = new ArrayList<>();
    private List<String> urls = new ArrayList<>();

    public void addOID(OIDDefinition d) {
      for (OIDDefinition t : definitions) {
        if (d.matches(t)) {
          return;
        }
      }
      definitions.add(d);
      if (!urls.contains(d.getUrl())) {
        urls.add(d.getUrl());
      }
    }
    
    public void addOIDs(Collection<OIDDefinition> collection) {
      for (OIDDefinition t : collection) {
        addOID(t);
      }
    }
    
    public List<OIDDefinition> getDefinitions() {
      return definitions;
    }

    public void sort() {
      Collections.sort(definitions, new OIDDefinitionComparer());
      Collections.sort(urls);
    }
    public String describe() {
      CommaSeparatedStringBuilder b = new CommaSeparatedStringBuilder();
      for (OIDDefinition d : definitions) {
        b.append(d.summary());
      }
      return b.toString();
    }

    public String chooseBestUrl() {
      for (OIDDefinition d : definitions) {
        if (d.getPackageSrc() == null) {
          return d.getUrl();
        }
      }
      for (OIDDefinition d : definitions) {
        if (d.getUrl().startsWith("http://hl7.org/fhir/")) {
          return d.getUrl();
        }
      }
      for (OIDDefinition d : definitions) {
        if (!d.getUrl().contains("vsac")) {
          return d.getUrl();
        }
      }
      return null;
    }

    public int urlCount() {
      return urls.size();
    }

    public String getUrl() {
      return urls.iterator().next();
    }
  }
  /**
   * Get the version of the base definitions loaded in context
   * This *does not* have to be 5.0 (R5) - the context can load other versions
   * 
   * Note that more than one version might be loaded at once, but one version is always the default / master
   * 
   * @return
   */
  public String getVersion();

  /**
   * Get the UCUM service that provides access to units of measure reasoning services 
   * 
   * This service might not be available 
   * 
   * @return
   */
  public UcumService getUcumService();
  public void setUcumService(UcumService ucumService);

  /**
   * Get a validator that can check whether a resource is valid 
   * 
   * @return a prepared generator
   * @throws FHIRException 
   * @
   */
  public IResourceValidator newValidator() throws FHIRException;

  // -- resource fetchers ---------------------------------------------------

  /**
   * Find an identified resource. The most common use of this is to access the the 
   * standard conformance resources that are part of the standard - structure 
   * definitions, value sets, concept maps, etc.
   * 
   * Also, the narrative generator uses this, and may access any kind of resource
   * 
   * The URI is called speculatively for things that might exist, so not finding 
   * a matching resource, return null, not an error
   * 
   * The URI can have one of 3 formats:
   *  - a full URL e.g. http://acme.org/fhir/ValueSet/[id]
   *  - a relative URL e.g. ValueSet/[id]
   *  - a logical id e.g. [id]
   *  
   * It's an error if the second form doesn't agree with class_. It's an 
   * error if class_ is null for the last form
   * 
   * class can be Resource, DomainResource or CanonicalResource, which means resource of all kinds
   * 
   * @param resource
   * @param Reference
   * @return
   * @throws FHIRException 
   * @throws Exception
   */
  public <T extends Resource> T fetchResource(Class<T> class_, String uri);
  public <T extends Resource> T fetchResourceRaw(Class<T> class_, String uri);
  public <T extends Resource> T fetchResourceWithException(Class<T> class_, String uri) throws FHIRException;
  public <T extends Resource> T fetchResourceWithException(Class<T> class_, String uri, Resource sourceOfReference) throws FHIRException;
  public <T extends Resource> T fetchResource(Class<T> class_, String uri, String version);
  public <T extends Resource> T fetchResource(Class<T> class_, String uri, FhirPublication fhirVersion);
  public <T extends Resource> T fetchResource(Class<T> class_, String uri, String version, FhirPublication fhirVersion);

  /** has the same functionality as fetchResource, but passes in information about the source of the 
   * reference (this may affect resolution of version)
   *  
   * @param <T>
   * @param class_
   * @param uri
   * @param canonicalForSource
   * @return
   */
  public <T extends Resource> T fetchResource(Class<T> class_, String uri, Resource sourceOfReference);

  /** 
   * Fetch all the resources of a particular type. if class == (null | Resource | DomainResource | CanonicalResource) return everything
   *  
   * @param <T>
   * @param class_
   * @param uri
   * @param canonicalForSource
   * @return
   */
  public <T extends Resource> List<T> fetchResourcesByType(Class<T> class_, FhirPublication fhirVersion);
  public <T extends Resource> List<T> fetchResourcesByType(Class<T> class_);


  /**
   * Fetch all the resources for the given URL - all matching versions
   * 
   * @param url
   * @return
   */
  public <T extends Resource> List<T> fetchResourcesByUrl(Class<T> class_, String url);
  
  /**
   * Variation of fetchResource when you have a string type, and don't need the right class
   * 
   * The URI can have one of 3 formats:
   *  - a full URL e.g. http://acme.org/fhir/ValueSet/[id]
   *  - a relative URL e.g. ValueSet/[id]
   *  - a logical id e.g. [id]
   *  
   * if type == null, the URI can't be a simple logical id
   * 
   * @param type
   * @param uri
   * @return
   */
  public Resource fetchResourceById(String type, String uri);
  public Resource fetchResourceById(String type, String uri, FhirPublication fhirVersion);

  /**
   * find whether a resource is available. 
   * 
   * Implementations of the interface can assume that if hasResource ruturns 
   * true, the resource will usually be fetched subsequently
   * 
   * @param class_
   * @param uri
   * @return
   */
  public <T extends Resource> boolean hasResource(Class<T> class_, String uri);
  public <T extends Resource> boolean hasResource(Class<T> class_, String uri, Resource sourceOfReference);
  public <T extends Resource> boolean hasResource(Class<T> class_, String uri, FhirPublication fhirVersion);

  /**
   * cache a resource for later retrieval using fetchResource.
   * 
   * Note that various context implementations will have their own ways of loading
   * rseources, and not all need implement cacheResource.
   * 
   * If the resource is loaded out of a package, call cacheResourceFromPackage instead
   * @param res
   * @throws FHIRException 
   */
  public void cacheResource(Resource res) throws FHIRException;

  /**
   * cache a resource for later retrieval using fetchResource.
   * 
   * The package information is used to help manage the cache internally, and to 
   * help with reference resolution. Packages should be define using cachePackage (but don't have to be)
   *    
   * Note that various context implementations will have their own ways of loading
   * rseources, and not all need implement cacheResource
   * 
   * @param res
   * @throws FHIRException 
   */
  public void cacheResourceFromPackage(Resource res, PackageInformation packageInfo) throws FHIRException;

  /**
   * Inform the cache about package dependencies. This can be used to help resolve references
   * 
   * Note that the cache doesn't load dependencies
   *  
   * @param packageInfo
   */
  public void cachePackage(PackageInformation packageInfo);

  // -- profile services ---------------------------------------------------------

  /**
   * @return a list of the resource names defined for this version
   */
  public List<String> getResourceNames();
  public List<String> getResourceNames(FhirPublication fhirVersion);
  /**
   * @return a set of the resource names defined for this version
   */
  public Set<String> getResourceNamesAsSet();
  public Set<String> getResourceNamesAsSet(FhirPublication fhirVersion);

  // -- Terminology services ------------------------------------------------------

  /**
   * Set the expansion parameters passed through the terminology server when txServer calls are made
   * 
   * Note that the Validation Options override these when they are specified on validateCode
   */
  public Parameters getExpansionParameters();

  /**
   * Get the expansion parameters passed through the terminology server when txServer calls are made
   * 
   * Note that the Validation Options override these when they are specified on validateCode
   */
  public void setExpansionParameters(Parameters expParameters);

  // these are the terminology services used internally by the tools
  /**
   * Find the code system definition for the nominated system uri. 
   * return null if there isn't one (then the tool might try 
   * supportsSystem)
   * 
   * This is a short cut for fetchResource(CodeSystem.class...)
   * 
   * @param system
   * @return
   */
  public CodeSystem fetchCodeSystem(String system);
  public CodeSystem fetchCodeSystem(String system, String version);
  public CodeSystem fetchCodeSystem(String system, FhirPublication fhirVersion);
  public CodeSystem fetchCodeSystem(String system, String version, FhirPublication fhirVersion);

  /**
   * Like fetchCodeSystem, except that the context will find any CodeSysetm supplements and merge them into the
   * @param system
   * @return
   */
  public CodeSystem fetchSupplementedCodeSystem(String system);
  public CodeSystem fetchSupplementedCodeSystem(String system, String version);
  public CodeSystem fetchSupplementedCodeSystem(String system, FhirPublication fhirVersion);
  public CodeSystem fetchSupplementedCodeSystem(String system, String version, FhirPublication fhirVersion);

  /**
   * True if the underlying terminology service provider will do 
   * expansion and code validation for the terminology. Corresponds
   * to the extension 
   * 
   * http://hl7.org/fhir/StructureDefinition/capabilitystatement-supported-system
   * 
   * in the Conformance resource
   * 
   * Not that not all supported code systems have an available CodeSystem resource
   * 
   * @param system
   * @return
   * @throws Exception 
   */
  public boolean supportsSystem(String system) throws TerminologyServiceException;
  public boolean supportsSystem(String system, FhirPublication fhirVersion) throws TerminologyServiceException;

  /**
   * ValueSet Expansion - see $expand
   *  
   * @param source
   * @return
   */
  public ValueSetExpansionOutcome expandVS(ValueSet source, boolean cacheOk, boolean heiarchical);

  public ValueSetExpansionOutcome expandVS(ValueSet source, boolean cacheOk, boolean heiarchical, int count);

  /**
   * ValueSet Expansion - see $expand
   *  
   * @param source
   * @return
   */
  public ValueSetExpansionOutcome expandVS(ValueSet source, boolean cacheOk, boolean heiarchical, boolean incompleteOk);

  public ValueSetExpansionOutcome expandVS(String uri, boolean cacheOk, boolean heiarchical, int count); // set to 0 to just check existence
  
  /**
   * ValueSet Expansion - see $expand, but resolves the binding first
   *  
   * @param source
   * @return
   * @throws FHIRException 
   */
  public ValueSetExpansionOutcome expandVS(Resource src, ElementDefinitionBindingComponent binding, boolean cacheOk, boolean heiarchical) throws FHIRException;

  /**
   * Value set expanion inside the internal expansion engine - used 
   * for references to supported system (see "supportsSystem") for
   * which there is no value set. 
   * 
   * @param inc
   * @return
   * @throws FHIRException 
   */
  ValueSetExpansionOutcome expandVS(ITerminologyOperationDetails opCtxt, ConceptSetComponent inc, boolean hierarchical, boolean noInactive) throws TerminologyServiceException;

  /**
   * get/set the locale used when creating messages
   * 
   * todo: what's the difference?
   * 
   * @return
   */
  Locale getLocale();
  void setLocale(Locale locale);

  @Deprecated
  void setValidationMessageLanguage(Locale locale);

  /**
   * Access to the contexts internationalised error messages
   * 
   * For rendering internationalization, see RenderingContext
   *  
   * @param theMessage
   * @param theMessageArguments
   * @return
   */
  String formatMessage(String theMessage, Object... theMessageArguments);
  String formatMessagePlural(Integer pluralNum, String theMessage, Object... theMessageArguments);

  /**
   * Validation of a code - consult the terminology infrstructure and/or service 
   * to see whether it is known. If known, return a description of it
   * 
   * note: always return a result, with either an error or a code description
   *  
   * corresponds to 2 terminology service calls: $validate-code and $lookup
   * 
   * in this case, the system will be inferred from the value set. It's an error to call this one without the value set
   * 
   * @param options - validation options (required)
   * @param code he code to validate (required)
   * @param vs the applicable valueset (required)
   * @return
   */
  public ValidationResult validateCode(ValidationOptions options, String code, ValueSet vs);

  /**
   * Validation of a code - consult the terminology infrstructure and/or service 
   * to see whether it is known. If known, return a description of it
   * 
   * note: always return a result, with either an error or a code description
   *  
   * corresponds to 2 terminology service calls: $validate-code and $lookup
   * 
   * @param options - validation options (required)
   * @param system - equals Coding.system (required)
   * @param code - equals Coding.code (required)
   * @param display - equals Coding.display (optional)
   * @return
   */
  public ValidationResult validateCode(ValidationOptions options, String system, String version, String code, String display);

  /**
   * Validation of a code - consult the terminology infrstructure and/or service 
   * to see whether it is known. If known, return a description of it
   * 
   * note: always return a result, with either an error or a code description
   *  
   * corresponds to 2 terminology service calls: $validate-code and $lookup
   * 
   * @param options - validation options (required)
   * @param system - equals Coding.system (required)
   * @param code - equals Coding.code (required)
   * @param display - equals Coding.display (optional)
   * @param vs the applicable valueset (optional)
   * @return
   */
  public ValidationResult validateCode(ValidationOptions options, String system, String version, String code, String display, ValueSet vs);

  /**
   * Validation of a code - consult the terminology infrstructure and/or service 
   * to see whether it is known. If known, return a description of it
   * 
   * note: always return a result, with either an error or a code description
   *  
   * corresponds to 2 terminology service calls: $validate-code and $lookup
   * 
   * Note that this doesn't validate binding strength (e.g. is just text allowed?)
   * 
   * @param options - validation options (required)
   * @param code - CodeableConcept to validate
   * @param vs the applicable valueset (optional)
   * @return
   */
  public ValidationResult validateCode(ValidationOptions options, CodeableConcept code, ValueSet vs);

  /**
   * Validation of a code - consult the terminology infrstructure and/or service 
   * to see whether it is known. If known, return a description of it
   * 
   * note: always return a result, with either an error or a code description
   *  
   * corresponds to 2 terminology service calls: $validate-code and $lookup
   * 
   * in this case, the system will be inferred from the value set. It's an error to call this one without the value set
   * 
   * @param options - validation options (required)
   * @param code - Coding to validate
   * @param vs the applicable valueset (optional)
   * @return
   */
  public ValidationResult validateCode(ValidationOptions options, Coding code, ValueSet vs);

  /** 
   * See comments in ValidationContextCarrier. This is called when there might be additional value sets etc 
   * available in the context, but we don't want to pre-process them. 
   * 
   * @param options
   * @param code
   * @param vs
   * @param ctxt
   * @return
   */
  public ValidationResult validateCode(ValidationOptions options, Coding code, ValueSet vs, ValidationContextCarrier ctxt);

  /**
   * Batch validate code - reduce latency and do a bunch of codes in a single server call. 
   * Each is the same as a validateCode
   * 
   * @param options
   * @param codes
   * @param vs
   */
  public void validateCodeBatch(ValidationOptions options, List<? extends CodingValidationRequest> codes, ValueSet vs);
  public void validateCodeBatchByRef(ValidationOptions options, List<? extends CodingValidationRequest> codes, String vsUrl);
  public OperationOutcome validateTxResource(ValidationOptions options, Resource resource);

  // todo: figure these out
  public Map<String, NamingSystem> getNSUrlMap();

  public void setLogger(@Nonnull org.hl7.fhir.r5.context.ILoggingService logger);
  public org.hl7.fhir.r5.context.ILoggingService getLogger();

  public boolean isNoTerminologyServer();
  public Set<String> getCodeSystemsUsed();
  public int getClientRetryCount();
  public IWorkerContext setClientRetryCount(int value);

  public TimeTracker clock();

  /**
   * This is a short cut for fetchResource(StructureDefinition.class, ...)
   * but it accepts a typename - that is, it resolves based on StructureDefinition.type 
   * or StructureDefinition.url. This only resolves to http://hl7.org/fhir/StructureDefinition/{typename}
   * 
   * @param typeName
   * @return
   */
  public StructureDefinition fetchTypeDefinition(String typeName);
  public StructureDefinition fetchTypeDefinition(String typeName, FhirPublication fhirVersion);

  /**
   * This finds all the structure definitions that have the given typeName
   * 
   * @param typeName
   * @return
   */
  public List<StructureDefinition> fetchTypeDefinitions(String n);
  public List<StructureDefinition> fetchTypeDefinitions(String n, FhirPublication fhirVersion);

  /**
   * return whether type is primitive type. This is called a lot, and needs a high performance implementation 
   * @param type
   * @return
   */
  public boolean isPrimitiveType(String type);

  /**
   * return whether type is data type. This is called a lot, and needs a high performance implementation 
   * @param type
   * @return
   */
  public boolean isDataType(String type);
  
  /**
   * Returns a set of keys that can be used to get binaries from this context.
   * The binaries come from the loaded packages (mostly the pubpack)
   *
   * @return a set of binaries or null
   */
  public Set<String> getBinaryKeysAsSet();

  /**
   * Returns true if this worker context contains a binary for this key.
   *
   * @param binaryKey
   * @return true if binary is available for this key
   */
  public boolean hasBinaryKey(String binaryKey);

  /**
   * Returns the binary for the key
   * @param binaryKey
   * @return
   */
  public byte[] getBinaryForKey(String binaryKey);

  /*
   * Todo: move these loaders out to IWorkerContextManager
   * 
   */
  /**
   * Load relevant resources of the appropriate types (as specified by the loader) from the nominated package
   * 
   * note that the package system uses lazy loading; the loader will be called later when the classes that use the context need the relevant resource
   * 
   * @param pi - the package to load
   * @param loader - an implemenation of IContextResourceLoader that knows how to read the resources in the package (e.g. for the appropriate version).
   * @return the number of resources loaded
   */
  int loadFromPackage(NpmPackage pi, IContextResourceLoader loader) throws FileNotFoundException, IOException, FHIRException;

  /**
   * Load relevant resources of the appropriate types (as specified by the loader) from the nominated package
   * 
   * note that the package system uses lazy loading; the loader will be called later when the classes that use the context need the relevant resource
   *
   * This method also loads all the packages that the package depends on (recursively)
   * 
   * @param pi - the package to load
   * @param loader - an implemenation of IContextResourceLoader that knows how to read the resources in the package (e.g. for the appropriate version).
   * @param pcm - used to find and load additional dependencies
   * @return the number of resources loaded
   */
  int loadFromPackageAndDependencies(NpmPackage pi, IContextResourceLoader loader, BasePackageCacheManager pcm) throws FileNotFoundException, IOException, FHIRException;

  public boolean hasPackage(String id, String ver);
  public boolean hasPackage(PackageInformation pack);
  public PackageInformation getPackage(String id, String ver);
  public PackageInformation getPackageForUrl(String url);

  public IWorkerContextManager.IPackageLoadingTracker getPackageTracker();
  public IWorkerContext setPackageTracker(IWorkerContextManager.IPackageLoadingTracker packageTracker);

  public String getSpecUrl();

  public PEBuilder getProfiledElementBuilder(PEElementPropertiesPolicy elementProps, boolean fixedProps);
  
  public boolean isForPublication();
  public void setForPublication(boolean value);

  /**
   * 
   * @param oid
   * @param resourceType - null to search on all resource types
   * @return
   */
  public OIDSummary urlsForOid(String oid, String resourceType);

  /**
   * this first does a fetch resource, and if nothing is found, looks in the 
   * terminology eco-system for a matching definition for the resource 
   * 
   * usually used (and so far only tested with) ValueSet.class
   * 
   * @param value
   * @return
   */
  public <T extends Resource> T findTxResource(Class<T> class_, String canonical, Resource sourceOfReference);
  public <T extends Resource> T findTxResource(Class<T> class_, String canonical);
  public <T extends Resource> T findTxResource(Class<T> class_, String canonical, String version);

  /**
   * ask the terminology system whether parent subsumes child. 
   * 
   * @return true if it does, false if it doesn't, and null if it's not know whether it does
   */
  public Boolean subsumes(ValidationOptions options, Coding parent, Coding child);

  public boolean isServerSideSystem(String url);

}