package org.hl7.fhir.dstu2.utils;

/*
  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, 
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  NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR 
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 */



import java.util.List;

import java.util.Locale;
import org.hl7.fhir.dstu2.formats.IParser;
import org.hl7.fhir.dstu2.formats.ParserType;
import org.hl7.fhir.dstu2.model.CodeableConcept;
import org.hl7.fhir.dstu2.model.Coding;
import org.hl7.fhir.dstu2.model.ConceptMap;
import org.hl7.fhir.dstu2.model.Resource;
import org.hl7.fhir.dstu2.model.StructureDefinition;
import org.hl7.fhir.dstu2.model.ValueSet;
import org.hl7.fhir.dstu2.model.ValueSet.ConceptDefinitionComponent;
import org.hl7.fhir.dstu2.model.ValueSet.ConceptSetComponent;
import org.hl7.fhir.dstu2.model.ValueSet.ValueSetExpansionComponent;
import org.hl7.fhir.dstu2.terminologies.ValueSetExpander.ValueSetExpansionOutcome;
import org.hl7.fhir.utilities.validation.ValidationMessage.IssueSeverity;


/**
 * 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 parsers, validators, narrative builders etc
 *    (you can't create these directly because they need 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
 */
public interface IWorkerContext {

  // -- Parsers (read and write instances) ----------------------------------------

  /**
   * Get a parser to read/write instances. Use the defined type (will be extended 
   * as further types are added, though the only currently anticipate type is RDF)
   * 
   * XML/JSON - the standard renderers
   * XHTML - render the narrative only (generate it if necessary)
   * 
   * @param type
   * @return
   */
  public IParser getParser(ParserType type);

  /**
   * Get a parser to read/write instances. Determine the type 
   * from the stated type. Supported value for type:
   * - the recommended MIME types
   * - variants of application/xml and application/json
   * - _format values xml, json
   * 
   * @param type
   * @return
   */	
  public IParser getParser(String type);

  /**
   * Get a JSON parser
   * 
   * @return
   */
  public IParser newJsonParser();

  /**
   * Get an XML parser
   * 
   * @return
   */
  public IParser newXmlParser();

  /**
   * Get a generator that can generate narrative for the instance
   * 
   * @return a prepared generator
   */
  public INarrativeGenerator getNarrativeGenerator(String prefix, String basePath);

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

  // -- 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 resouce, 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
   * 
   * @param resource
   * @param Reference
   * @return
   * @throws Exception
   */
  public <T extends Resource> T fetchResource(Class<T> class_, String uri);

  /**
   * 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);

  // -- profile services ---------------------------------------------------------
  
  public List<String> getResourceNames();
  
  // -- Terminology services ------------------------------------------------------

  // these are the terminology services used internally by the tools
  /**
   * Find a value set for the nominated system uri. 
   * return null if there isn't one (then the tool might try 
   * supportsSystem)
   * 
   * @param system
   * @return
   */
  public ValueSet fetchCodeSystem(String system);

  /**
   * 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/conformance-supported-system
   * 
   * in the Conformance resource
   * 
   * @param system
   * @return
   */
  public boolean supportsSystem(String system);

  /**
   * find concept maps for a source
   * @param url
   * @return
   */
  public List<ConceptMap> findMapsForSource(String url);  

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

  Locale getLocale();

  void setLocale(Locale locale);

  String formatMessage(String theMessage, Object... theMessageArguments);

  void setValidationMessageLanguage(Locale locale);

  public class ValidationResult {
    private ConceptDefinitionComponent definition;
    private IssueSeverity severity;
    private String message;
    
    public ValidationResult(IssueSeverity severity, String message) {
      this.severity = severity;
      this.message = message;
    }
    
    public ValidationResult(ConceptDefinitionComponent definition) {
      this.definition = definition;
    }

    public ValidationResult(IssueSeverity severity, String message, ConceptDefinitionComponent definition) {
      this.severity = severity;
      this.message = message;
      this.definition = definition;
    }
    
    public boolean isOk() {
      return definition != null;
    }

    public String getDisplay() {
      return definition == null ? "??" : definition.getDisplay();
    }

    public ConceptDefinitionComponent asConceptDefinition() {
      return definition;
    }

    public IssueSeverity getSeverity() {
      return severity;
    }

    public String getMessage() {
      return message;
    }
  }

  /**
   * Validation of a code - consult the terminology 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 system
   * @param code
   * @param display
   * @return
   */
  public ValidationResult validateCode(String system, String code, String display);

  /**
   * Validation of a code - consult the terminology service 
   * to see whether it is known. If known, return a description of it
   * Also, check whether it's in the provided value set
   * 
   * note: always return a result, with either an error or a code description, or both (e.g. known code, but not in the value set)
   *  
   * corresponds to 2 terminology service calls: $validate-code and $lookup
   * 
   * @param system
   * @param code
   * @param display
   * @return
   */
  public ValidationResult validateCode(String system, String code, String display, ValueSet vs);
  public ValidationResult validateCode(Coding code, ValueSet vs);
  public ValidationResult validateCode(CodeableConcept code, ValueSet vs);
  
  /**
   * Validation of a code - consult the terminology service 
   * to see whether it is known. If known, return a description of it
   * Also, check whether it's in the provided value set fragment (for supported systems with no value set definition)
   * 
   * note: always return a result, with either an error or a code description, or both (e.g. known code, but not in the value set)
   *  
   * corresponds to 2 terminology service calls: $validate-code and $lookup
   * 
   * @param system
   * @param code
   * @param display
   * @return
   */
  public ValidationResult validateCode(String system, String code, String display, ConceptSetComponent vsi);

  /**
   * returns the recommended tla for the type 
   * 
   * @param name
   * @return
   */
  public String getAbbreviation(String name);

  public List<StructureDefinition> allStructures();

  public StructureDefinition fetchTypeDefinition(String typeName);

}