/*
//
// Copyright (c) 1993-2012 Robert McNeel & Associates. All rights reserved.
// OpenNURBS, Rhinoceros, and Rhino3D are registered trademarks of Robert
// McNeel & Associates.
//
// THIS SOFTWARE IS PROVIDED "AS IS" WITHOUT EXPRESS OR IMPLIED WARRANTY.
// ALL IMPLIED WARRANTIES OF FITNESS FOR ANY PARTICULAR PURPOSE AND OF
// MERCHANTABILITY ARE HEREBY DISCLAIMED.
//				
// For complete openNURBS copyright information see <http://www.opennurbs.org>.
//
////////////////////////////////////////////////////////////////
*/

#if !defined(ON_MODEL_COMPONENT_INC_)
#define ON_MODEL_COMPONENT_INC_

/*
Description:
  The ON_ModelComponent class is a base class for all components in a
  model and manages the index, id and other information common to all
  components in a model.
*/
class ON_CLASS ON_ModelComponent : public ON_Object
{
  ON_OBJECT_DECLARE(ON_ModelComponent);

public:
  bool IsValid( class ON_TextLog* text_log = nullptr ) const override;

  void Dump( 
    ON_TextLog& 
    ) const override;

  unsigned int SizeOf() const override;


  ON__UINT32 DataCRC(
    ON__UINT32 current_remainder
    ) const override;

  ON_UUID ModelObjectId() const override;

public:

#pragma region RH_C_SHARED_ENUM [ON_ModelComponent::Type] [Rhino.DocObjects.ModelComponentType] [public:byte]
  ///<summary>
  ///The ON_ModelComponent::Type enum has a value for each explicit component type
  ///and two special values, Unset and Mixed. Use an ON_ModelComponentTypeIterator
  ///instance to iterate over the ON_ModelComponent::Type values.
  ///</summary>
  enum class Type : unsigned char
  {
    ///<summary>No value set.</summary>
    Unset = 0,
    ///<summary>Embedded image (bitmap) components.</summary>
    Image = 1,
    ///<summary>Texture mapping.</summary>
    TextureMapping = 2,
    ///<summary>Render material.</summary>
    RenderMaterial = 3,
    ///<summary>Line pattern (linetype).</summary>
    LinePattern = 4,
    ///<summary>Layer.</summary>
    Layer = 5,       
    ///<summary>Group.</summary>
    Group = 6,
    ///<summary>Text style.</summary>
    TextStyle = 7,
    ///<summary>AnnotationDimension style.</summary>
    DimStyle = 8,
    ///<summary>Render light.</summary>
    RenderLight = 9,
    ///<summary>Hatch pattern.</summary>
    HatchPattern = 10,
    ///<summary>Instance definition.</summary>
    InstanceDefinition = 11,
    ///<summary>Model objects (points, curves, surfaces, ..., annotation, page details, ...), including objects referenced by instance definitions.</summary>
    ModelGeometry = 12,
    ///<summary>History record.</summary>
    HistoryRecord = 13,
    ///<summary>Multiple component types.
    /// Used when a component type filter must include all explicit component types.
    ///</summary>
    Mixed = 0xFE
  };
#pragma endregion

  static ON_ModelComponent::Type ComponentTypeFromUnsigned(
    unsigned int component_type_as_unsigned
    );

  static const ON_wString ComponentTypeToString(
    ON_ModelComponent::Type
    );

  /*
  Parameters:
  component_type - [in]
  Returns:
    True if component_type is a valid enum value, 
    and not equal to ON_ModelComponent::Type::Unset.
  */
  static bool ComponentTypeIsValid(
    ON_ModelComponent::Type component_type
    );

  /*
  Parameters:
    component_type - [in]
  Returns:
    True if component_type is a valid enum value, 
    and not equal to ON_ModelComponent::Type::Unset, 
    and not equal to ON_ModelComponent::Type::Mixed.
  */
  static bool ComponentTypeIsValidAndNotMixed(
    ON_ModelComponent::Type component_type
    );

  /*
  Parameters:
    component_type - [in]
  Returns:
    True if component's of the specified type require uniquen names.
  Remarks:
    In general, component names ignore case and parent when testing for
    equality. 
    However, there are exceptions. Use
    ON_ModelComponent::UniqueNameIncludesParent() and
    ON_ModelComponent::UniqueNameIgnoresCase() 
    to test for exceptions.
  */
  static bool UniqueNameRequired(
    ON_ModelComponent::Type component_type
    );

  /*
  Parameters:
    component_type - [in]
  Returns:
    True if objects with the same name and different parents are considered
    to have a unique name. This typically means the user interface for the
    object names is some type of tree.
  Remarks:
    Currently, layers are the only object type where this property is true.
  */
  static bool UniqueNameIncludesParent(
    ON_ModelComponent::Type component_type
    );

  /*
  Parameters:
    component_type - [in]
  Returns:
    True if component names ignore case when testing for equality.
  Remarks:
    Currently all other component types except for groups ignore 
    case when testing for equality.
  */
  static bool UniqueNameIgnoresCase(
    ON_ModelComponent::Type component_type
    );

  static bool IndexRequired(
    ON_ModelComponent::Type component_type
    );

  /*
  Returns:
    True if a componenent name can begin with the first code point.
  Remarks:
    Component names cannot begin with a (, ), [, ], {, }, or space.
    These brackets can be the second or later code points.
    A space can be an interior code point.
  */
  static bool IsValidComponentNameFirstCodePoint(
    ON__UINT32 unicode_code_point
    );

  /*
  Parameters:
    length - [in]
      number of wchar_t elements in candidate_component_name[] or -1
      if it is a null terminated string.
    candidate_component_name - [in]
      The first code point is decoded from this string
      and passed to ON_ModelComponent::IsValidComponentNameFirstCodePoint().
  Returns:
    True if a componenent name can begin with the first code point.
  Remarks:
    Component names cannot begin with a (, ), [, ], {, }, or space.
    These brackets can be the second or later code points.
    A space can be an interior code point.
  */
  static bool IsValidComponentNameFirstCodePoint(
    int length,
    const wchar_t* candidate_component_name 
    );

  static bool IsValidComponentName(
    const wchar_t* candidate_component_name 
    );

  static bool IsValidComponentName(
    const ON_wString& candidate_component_name
    );

  static bool IsValidComponentName(
    size_t length,
    const wchar_t* candidate_component_name 
    );

  /*
  Parameters:
    model_component - [in]
    model_manfest - [in]
      current model contents
    valid_name - [in]
      Valid name for this component in a model with the specified manifest.
  Returns:
    true: model_component.Name() is valid
    false: model_component.Name() is not valid    
  */
  static bool IsValidComponentName(
    const class ON_ComponentManifest&  model_manfest,
    const ON_ModelComponent& model_component,
    bool bPermitReferencePrefix,
    ON_wString& valid_name
  );

public:
  static const ON_ModelComponent Unset;

  ON_ModelComponent() ON_NOEXCEPT;

  ~ON_ModelComponent() = default;
  
  // Locked status of source attributes is not copied to permit copy and modify operations.
  // Runtime serial number and content version number are not copied.
  ON_ModelComponent(
    const ON_ModelComponent& source
    );

  /*
  Description:
    Sets and locks the component type attribute.
  Parameters:
    component_type - [in]
  */
  ON_ModelComponent(
    ON_ModelComponent::Type component_type
    ) ON_NOEXCEPT;

  // Locked status of source attributes is not copied to permit copy and modify operations.
  ON_ModelComponent(
    ON_ModelComponent::Type component_type,
    const ON_ModelComponent& source
    ) ON_NOEXCEPT;
  
  /*
  Remarks:
    operator= will not change locked destination attributes.
    Locked status of source attributes is not copied to permit copy and modify operations.
  */
  ON_ModelComponent& operator=(const ON_ModelComponent& source);

  /*
  The ON_ModelComponent::Attributes enum is used to set bits that identify
  model component attributes.
  */
  enum Attributes : unsigned int
  {
    NoAttributes = 0U,

    ComponentSerialNumberAttribute = 0x0001U,
    TypeAttribute = 0x0002U,
    ModelSerialNumberAttribute = 0x0004U,
    IdAttribute = 0x0008U,
    IndexAttribute = 0x0010U,
    NameAttribute = 0x0020U,
    ParentIdAttribute = 0x0040U,
    DeletedNameAttribute = 0x0080U,
    ComponentStatusAttribute = 0x0100U,

    // Default model attributes saved in binary archives.
    // Id, ParentId, Name, Index
    // Do not include SystemComponentAttribute in BinaryArchiveAttributes
    BinaryArchiveAttributes = 0x78U,

    // Do not include SystemComponentAttribute in AllAttributes
    AllAttributes = 0x1FFU,

    SystemComponentAttribute = 0x8000U
  };

  unsigned int CopyFrom(
    const ON_ModelComponent& src,
    unsigned int attributes_filter
    );

  bool WriteModelComponentAttributes(
    class ON_BinaryArchive& archive,
    unsigned int attributes_filter
    ) const;

  bool ReadModelComponentAttributes(
    class ON_BinaryArchive& archive
    );
  
  ///////////////////////////////////////////////////////////////////////////////
  //
  // Model Serial Number interface
  //
  //  The ModelSerialNumber() identifies the model that manages the component.
  //  If the component is from some type of reference model, then one or both of
  //  the reference model serial number and InstanceDefinitionModelSerialNumber()
  //  identify the source model.
  //

  /*
  Description:
    Specify the model that is managing this component.
  Parameters:
    model_serial_number - [in]
      In Rhino, this is the document runtime serial number.
  Returns:
    true if the model_serial_number value was changed to component_model_serial_number or is already equal to component_model_serial_number.
    false if the model_serial_number value is locked and component_model_serial_number != locked value.
  */
  bool SetModelSerialNumber(
    unsigned int model_serial_number
    );

  /*
  Description:
    Specify the model that is managing this component.
  Parameters:
    model_serial_number - [in]
      In Rhino, this is the document runtime serial number.
    reference_model_serial_number - [in]
      In Rhino, this is the worksession reference model serial number.
      instance_definition_model_serial_number - [in]
      In Rhino, this is the linked instance definition model serial number.
  Returns:
    true if the model_serial_number value was changed to component_model_serial_number or is already equal to component_model_serial_number.
    false if the model_serial_number value is locked and component_model_serial_number != locked value.
  */
  bool SetModelSerialNumber(
    unsigned int model_serial_number,
    unsigned int reference_model_serial_number,
    unsigned int instance_definition_model_serial_number
    );

  /*
  Returns:
    A value identifing the model that manages this component.
  Remarks:
    If the component is being managed by a model, this value identifies the model.
    In Rhino, this value is the document runtime serial number.
    Typically this value is set and locked by the code that adds 
    a component to a model.
    This value is copied by the copy constructor and operator=. 
    This value is not saved in .3dm archives.
  */
  unsigned int ModelSerialNumber() const;

  /*
  Returns:
    When a compoent is in a model for reference, this value identifies the
    reference model.
  Remarks:
    Reference components are not saved in .3dm archives.
    Typically this value is set and locked by the code that adds 
    a component to a model.
    This value is copied by the copy constructor and operator=. 
    This value is not saved in .3dm archives.

    In Rhino, this value is a worksession model runtime serial number and 
    these values are used.
           0: not from a worksession reference model
           1: from an unidentified reference model
      2-1000: reserved for future use
       >1000: worksession reference model serial number
  */
  unsigned int ReferenceModelSerialNumber() const;

  /*
  Returns:
    When a component is in a model as part of the information required
    for a linked instance definition, this value identifies the the linked
    instance definition reference model.
  Remarks:
    Reference components are not saved in .3dm archives.
    Typically this value is set and locked by the code that adds 
    a component to a model.
    This value is copied by the copy constructor and operator=. 
    This value is not saved in .3dm archives.

    In Rhino, this value is a linked instance definition runtime serial number
    and  these values are used..
            0: Active model component.
       1-1000: reserved for future use
        >1000: linked instance defintion serial number
  */
  unsigned int InstanceDefinitionModelSerialNumber() const;

  /*
  Description:
    Sets the model serial number, reference model serial number and instance
    definition model serial number values to 0 and flags these values
    as unset.
  */
  bool ClearModelSerialNumber();

  /*
  Description:
    Calling LockModelSerialNumber() will prohibit future changes to the 
    ModelSerialNumber(), ReferenceModelSerialNumber(), and
    InstanceDefinitionModelSerialNumber() attributes.
  */
  void LockModelSerialNumber();

  /*
  Returns:
    True if the ModelSerialNumber(), ReferenceModelSerialNumber(), and
    InstanceDefinitionModelSerialNumber() attributes are locked.
  */
  bool ModelSerialNumberIsLocked() const;

  /*
  Returns:
    True if the ModelSerialNumber(), ReferenceModelSerialNumber(), and
    InstanceDefinitionModelSerialNumber() attributes are set.
  */
  bool ModelSerialNumberIsSet() const;

  /*
  Returns 
    True if ReferenceModelSerialNumber() or InstanceDefinitionModelSerialNumber() are not zero.
  */
  bool IsReferenceComponent() const;

  ///////////////////////////////////////////////////////////////////////////////
  //
  // Type interface
  //

  /*
  Returns:
    Value of the Type attribute.
  Remarks:
    If the component is in a model, then the component_type is unique for all components
    of identical type in the model and is locked.
  */
  ON_ModelComponent::Type ComponentType() const;

  /*
  Parameters:
    component_component_type - [in]
  Returns:
    true if the component_type value was changed to component_component_type or is already equal to component_component_type.
    false if the component_type value is locked and component_component_type != locked value.
  */
  bool SetComponentType(
    ON_ModelComponent::Type component_component_type
    );

  /*
  Description:
    Set the model serial number value to the ON_ModelComponent::Unset.Type()
    and change the state so TypeIsSet() returns false.
  */
  bool ClearComponentType();

  /*
  Description:
    Calling LockType() will prhibit future changes to the Type attribute.
  */
  void LockComponentType();

  /*
  Returns:
    True if the Type attribute is locked.
  */
  bool ComponentTypeIsLocked() const;

  /*
  Returns:
    True if the Type attribute is set.
  */
  bool ComponentTypeIsSet() const;

  ///////////////////////////////////////////////////////////////////////////////
  //
  // Id interface
  //
  //  The component id is intended to be unique in the context of a model.
  //

  /*
  Returns:
    Value of the Id attribute.
  Remarks:
    If the component is in a model, then the id is unique for all components in
    the model and is locked.
  */
  const ON_UUID& Id() const;

  bool IdIsNil() const;
  bool IdIsNotNil() const;

  /*
  Parameters:
    component_id - [in]
  Returns:
    true if the id value was changed to component_id or is already equal to component_id.
    false if the id value is locked and component_id != locked value.
  */
  bool SetId(
    const ON_UUID& component_id
    );

  /*
  Description:
    Sets the id to a new value created by ON_CreateUuid().
  Returns:
    ON_nil_uuid: Id is locked.
    Otherwise the value of the new id.
  */
  const ON_UUID& SetId();

  /*
  Description:
    If the it is nil, call SetId().
  */
  const ON_UUID& IfIdIsNilSetId();

  /*
  Description:
    Sets the id to a new value created by ON_CreateUuid() and locks the 
    id attribute so it cannot be changed.
  Returns:
    ON_nil_uuid: Id is locked.
    Otherwise the value of the new id.
  */  
  const ON_UUID& SetAndLockId();
  

  /*
  Description:
    Set the component id value to the ON_ModelComponent::Unset.ModelComponentId()
    and change the state so ModelComponentIdIsSet() returns false.
  */
  bool ClearId();

  /*
  Description:
    Calling LockModelComponentId() will prhibit future changes to the ModelComponentId attribute.
  */
  void LockId();

  /*
  Returns:
    True if the ModelComponentId attribute is locked.
  */
  bool IdIsLocked() const;

  /*
  Returns:
    True if the ModelComponentId attribute is set.
  */
  bool IdIsSet() const;


  ///////////////////////////////////////////////////////////////////////////////
  //
  // Index interface
  //
  //  When a component is managed by a model, the component index is identifies
  //  the component within the context of that model.
  //

  /*
  Returns:
    Value of the runtime model component index attribute.
  Remarks:
    If the component is in a model, then the index is unique for all components
    of identical type in the model and is locked.
    If the index has not been set, ON_UNSET_INT_INDEX is returned.
    The Index() value can change when saved in an archive (.3dm file).
    Use the Id() when you need to reference model compoenents in an archive.
  */
  int Index() const;

  /*
  Returns:
    Value of the model component index attribute.
  Parameters:
    unset_index_value - [in]
      Value to return if the index has not been set.
      ON_UNSET_INT_INDEX or indices of default components are often
      used for this parameter.
  Returns:
    IndexIsSet() ? Index() : unset_index_value;
  Remarks:
    If the component is in a model, then the index is unique for all components
    of identical type in the model and is locked.
  */
  int Index(
    int unset_index_value
    ) const;

  /*
  Parameters:
    component_index - [in]
  Returns:
    true if the index value was changed to component_index or is already equal to component_index.
    false if the index value is locked and component_index != locked value.
  */
  bool SetIndex(
    int component_index
    );

  /*
  Description:
    Set the component index value to the ON_ModelComponent::Unset.ModelComponentIndex()
    and change the state so ModelComponentIndexIsSet() returns false.
  */
  bool ClearIndex();

  /*
  Description:
    Calling LockModelComponentIndex() will prhibit future changes to the ModelComponentIndex attribute.
  */
  void LockIndex();

  /*
  Returns:
    True if the ModelComponentIndex attribute is locked.
  */
  bool IndexIsLocked() const;

  /*
  Returns:
    True if the ModelComponentIndex attribute is set.
  */
  bool IndexIsSet() const;

  ///////////////////////////////////////////////////////////////////////////////
  //
  // Parent object interface
  //
  //
  const ON_UUID& ParentId() const;

  bool ParentIdIsNil() const;
  bool ParentIdIsNotNil() const;

  bool SetParentId(
    const ON_UUID& parent_id
    );
  bool ClearParentId();
  void LockParentId();
  bool ParentIdIsLocked() const;
  bool ParentIdIsSet() const;

  ///////////////////////////////////////////////////////////////////////////////
  //
  // Model component locked, hidden, deleted, selected, highlights, damaged, ... status interface
  //
  //
  ON_ComponentStatus ModelComponentStatus() const;

  bool SetModelComponentStatus(
    ON_ComponentStatus component_status
    );

  bool ClearModelComponentStatus();

  void LockModelComponentStatus();

  bool ModelComponentStatusIsLocked() const;

  bool ModelComponentStatusIsSet() const;

  /*
  Returns:
    The component's deleted state.
  Remarks:
    Deleted components can be undeleted.
  */
  bool IsDeleted() const;

  /*
  Parameters:
    bDeleted - [in]
    manifest - [in/out]
      optional manifest to update
  Returns:
    True if the component's deleted state was changed from
    !bDeleted to bDeleted and all other name and manifest information
    was updated as expected.
  */
  bool SetDeletedModelComponentState(
    bool bDeleted,
    class ON_ComponentManifest* manifest
    );

  /*
  Returns:
    The component's user interface locked state.
  Remarks:
    This is a user interface locked state and does not effect
    changing the component values.
  */
  bool IsLocked() const;

  void SetLockedModelComponentState(
    bool bLocked 
    );

  /*
  Returns:
    The component's user interface hidden state.
  Remarks:
    This is a user interface hidden state and does not effect
    changing the component values.
  */
  bool IsHidden() const;

  void SetHiddenModelComponentState(
    bool bHidden 
    );


  ///////////////////////////////////////////////////////////////////////////////
  //
  // Name interface
  //
  //

  /*
  Returns:
    Value of the Name attribute.
  Remarks:
    If the component is in a model, then the name is unique among all components in
    the model. Names are formatted as reference : parent::leaf. 
    For example in "A.3dm : Z", "A.3dm" is the reference and "Z" is the leaf. 
    For a layer full path "X::Y::Z", "X::Y" is the parent and "Z" is the leaf.
    For most models, only the leaf is present in the name. 
    The reference portion appears when a model component originates in a reference file
    (a linked instance definition with reference component names or a worksession reference).
    Components with a tree hierarchy, like layers, can have a parent and leaf.
  */
  const ON_wString Name() const;

  const ON_wString DeletedName() const;

  /*
  Parameters:
    component_name - [out]
  Returns:
    A pointer to the string in component_name.
  */
  const wchar_t* GetName(
    ON_wString& component_name
    ) const;
  
  /*
  Description:
    Get a platform independent hash of the name suitable for equality testing
    and binary searching.
    When testing for equality or doing binary searches, using ON_NameHash values
    is faster than using the CompareName or ON_wString::CompareAttributeName.
  */
  const ON_NameHash& NameHash() const;
  const ON_NameHash& DeletedNameHash() const;

  /*
  Parameters:
    new_name - [in]      
  Returns:
    If new_name is empty or a valid component name, then name hash this component would have if SetName(new_name) were called.
    If new_name is not valid, then ON_NameHash::UnsetNameHash is returned.
  Remarks:
    This function trims leading and trailing white space, includes the parent id when 
    ON_ModelComponent::UniqueNameIncludesParent(ComponentType()) is true,
    and uses ON_ModelComponent::IsValidComponentName() to determine if a 
    non-empty name is valid.    
  */
  const ON_NameHash NewNameHash(
    const wchar_t* new_name
    ) const;

  /*
  Description:
    Returns the string " : ".  This is the string Rhino uses
    to separate the reference file names from and model component names
    read from those files.

  Example:
      File A.3dm contains a layer "alpha", dimstyle "a1", an embedded block "A_blk",
      and a linked block "X" referencing B.3dm with reference component names.
      File B.3dm contains a layer "beta", dimstyle "b1", an embedded block "B_blk",
      and linked block "Y" referencing C.3dm.
      File C.3dm contains a layer gamma, dimstyle "c1", an embedded block "C_blk",
      and linked block "Z" referencing D.3dm.
      File D.3dm contains a layer "delta", dimstyle "d1", and an embedded block "D_blk".
      
      Reading file A.3dm will craete the following components:
      Layers:
        alpha
        X>B.3dm
          beta (full layer path "X>B.3dm::beta")
        Y>C.3dm
          gamma (full layer path "Y>C.3dm::gamma")
        Z>D.3dm
          delta (full layer path "Z>D.3dm::delta")
      Blocks:
        X
        A_blk
        Y
        B.3dm : B_blk
        Z
        C.3dm : C_blk
        D.3dm : D_blk
      Annotation styles
        a1
        B.3dm : b1
        C.3dm : c1
        D.3dm : d1

  See Also:
    ON_ModelComponent::ReferencePrefixDelimiter = " : "
    ON_ModelComponent::ReferencePrefixSeparator = ">"
    ON_ModelComponent::NamePathSeparator = "::"
  */
  static const ON_wString ReferencePrefixDelimiter;

  /*
  Description:
    Returns the string ">".  This is the string Rhino uses
    to separate the block definition name and linked file name
    in grandparent layers.

  Example:
      File A.3dm contains a layer "alpha", dimstyle "a1", an embedded block "A_blk",
      and a linked block "X" referencing B.3dm with reference component names.
      File B.3dm contains a layer "beta", dimstyle "b1", an embedded block "B_blk",
      and linked block "Y" referencing C.3dm.
      File C.3dm contains a layer gamma, dimstyle "c1", an embedded block "C_blk",
      and linked block "Z" referencing D.3dm.
      File D.3dm contains a layer "delta", dimstyle "d1", and an embedded block "D_blk".
      
      Reading file A.3dm will craete the following components:
      Layers:
        alpha
        X>B.3dm
          beta (full layer path "X>B.3dm::beta")
        Y>C.3dm
          gamma (full layer path "Y>C.3dm::gamma")
        Z>D.3dm
          delta (full layer path "Z>D.3dm::delta")
      Blocks:
        X
        A_blk
        Y
        B.3dm : B_blk
        Z
        C.3dm : C_blk
        D.3dm : D_blk
      Annotation styles
        a1
        B.3dm : b1
        C.3dm : c1
        D.3dm : d1

  See Also:
    ON_ModelComponent::ReferencePrefixDelimiter = " : "
    ON_ModelComponent::ReferencePrefixSeparator = ">"
    ON_ModelComponent::NamePathSeparator = "::"
  */
  static const ON_wString ReferencePrefixSeparator;


  /*
  Description:
    Returns the string "::".  This is the string Rhino uses in layer
    full path names to separate the names of individual layers.

  Example:
      If a model has layers
      A
        B
          C
      then the full path names are
      "A", "A::B", "A::B::C".

  See Also:
    ON_ModelComponent::ReferencePrefixDelimiter = " : "
    ON_ModelComponent::ReferencePrefixSeparator = ">"
    ON_ModelComponent::NamePathSeparator = "::"
  */
  static const ON_wString NamePathSeparator;

  ///*
  //Description:
  //Parameters:
  //  reference_prefix - [in]
  //Returns:
  //  The worksession component name reference prefix.
  //Example:
  //  "[ A.3dm ]" = ON_ModelComponent::WorksessionReferencePrefix("A.3dm")
  //*/
  //static const ON_wString WorksessionReferencePrefix(
  //  const wchar_t* reference_prefix,
  //  bool bAppendReferencePrefixDelimiter
  //);


  /*
  Description:
    Test a string to see if its beginning matches the 
    string returned by ON_ModelComponent::NameReferenceDelimiter.
  Parameters:
    s - [in];
      string to test.
  Returns:
    null:
      The beginning of the string does not match ON_ModelComponent::NameReferenceDelimiter.
    non-null:
      The beginning of the string matches ON_ModelComponent::NameReferenceDelimiter.
      The returned pointer is the first character in s after the last character
      of the delimiter.  Put another way, if the beginning of s matches
      the string ON_ModelComponent::NameReferenceDelimiter, then the returned pointer is
      s + ON_ModelComponent::NameReferenceDelimiter.Length().
  */
  static const wchar_t* IsReferencePrefixDelimiter(
    const wchar_t* s
  );

  /*
  Description:
    Test a string to see if its beginning matches the 
    string returned by ON_ModelComponent::NameReferenceSeparator.
  Parameters:
    s - [in];
      string to test.
  Returns:
    null:
      The beginning of the string does not match ON_ModelComponent::NameReferenceSeparator.
    non-null:
      The beginning of the string matches ON_ModelComponent::NameReferenceSeparator.
      The returned pointer is the first character in s after the last character
      of the delimiter.  Put another way, if the beginning of s matches
      the string ON_ModelComponent::NameReferenceSeparator, then the returned pointer is
      s + ON_ModelComponent::NameReferenceSeparator.Length().
  */
  static const wchar_t* IsReferencePrefixSeparator(
    const wchar_t* s
  );

  /*
  Description:
    Test a string to see if its beginning matches the 
    string returned by ON_ModelComponent::NamePathSeparator.
  Parameters:
    s - [in];
      string to test.
  Returns:
    null:
      The beginning of the string does not match ON_ModelComponent::NamePathSeparator.
    non-null:
      The beginning of the string matches ON_ModelComponent::NamePathSeparator.
      The returned pointer is the first character in s after the last character
      of the delimiter.  Put another way, if the beginning of s matches
      the string ON_ModelComponent::NamePathSeparator, then the returned pointer is
      s + ON_ModelComponent::NamePathSeparator.Length().
  */
  static const wchar_t* IsNamePathSeparator(
    const wchar_t* s
  );

  /*
  Example:
    If a full layer name is "A.3dm : X::Y::Z", then
    reference_prefix = "A.3dm"
    name_parent = "X::Y"
    name_leaf = "Z"
  */
  static void SplitName(
    const wchar_t* name,
    ON_wString& reference_prefix,
    ON_wString& name_parent,
    ON_wString& name_leaf
  );

  /*
  Parameters:
    name - [in]
  Example:
    If the name is "A.3dm : X", then "A.3dm" is returned.
  */
  static const ON_wString NameReferencePrefix(
    const wchar_t* name
  );

  /*
  Parameters:
    name - [in]
    bIncludeReference - [in]
  Example:
    If the name is "A.3dm>B.3dm : X::Y::Z" and bIncludeReference is true, 
    then "A.3dm>B.3dm : X::Y" is returned.
    If the name is "A.3dm>B.3dm : X::Y::Z" and bIncludeReference is false, 
    then "X::Y" is returned.
  */
  static const ON_wString NameParent(
    const wchar_t* name,
    bool bIncludeReference
  );

  /*
  Example:
    If the name is "A.3dm>B.3dm : X::Y::Z", 
    then name_leaf = "Z" is returned.
  */
  static const ON_wString NameLeaf(
    const wchar_t* name
  );

  /*
  Parameters:
    name - [in]
  Example:
    If the name is "A.3dm : X", then "X" is returned.
  */
  static const ON_wString RemoveReferencePrefix(
    const wchar_t* name
  );

  /*
  Description:
    Remove all occurances of ON::NameReferenceDelimiter() from name.
  */
  static const ON_wString RemoveAllReferencePrefixDelimiters(
    const wchar_t* name
  );

  /*
  Description:
    Remove any trailing occurance of ON_ModelComponent::NameReferenceDelimiter from name.
  Example:
    "A.3dm" = ON_ModelComponent::RemoveTrailingRemoveReferencePrefixDelimiter("A.3dm : ");
  */
  static const ON_wString RemoveTrailingReferencePrefixDelimiter(
    const wchar_t* name
  );

  /*
  Description:
    Remove any trailing occurance of ON_ModelComponent::NameReferenceSeparator from name.
  */
  static const ON_wString RemoveTrailingReferencePrefixSeparator(
    const wchar_t* name
  );

  /*
  Description:
    Remove any trailing occurance of ON_ModelComponent::NamePathSeparator from name.
  */
  static const ON_wString RemoveTrailingNamePathSeparator(
    const wchar_t* name
  );


  
private:
  const ON_NameHash& Internal_NameHash() const;

public:
  /*
  Description:
    Expert user function that gets a pointer to the name.
  Returns:
    A pointer to the string that contains the name. This pointer
    must be used immediately and then discarded before any code
    can possibly call SetName() or the ON_ModelComponent destructor
    could be called.
  Remarks:
    About the only good use for this function is when a model compoenent is
    peristent and the name is needed for a formatted string.  For any
    other use, call the Name() function and store the result in an
    ON_wString.  This function is dangerous because the returned pointer
    will be invalid if SetName() is called.
  */
  const wchar_t* NameAsPointer() const;

  /*
  Returns:
    true if the name is unset or is set to the empty string.
  */
  bool NameIsEmpty() const;

  /*
  Returns:
    true if the name is set and the value is not the empty string.
  */
  bool NameIsNotEmpty() const;

  /*
  Parameters:
    component_name - [in]
      Leading and trailing nonzero unicode code points with values <= ON_wString::Space are ignored.
  Returns:
    true 
      if the name attribute was changed to component_name or is already equal to component_name.
    false 
      False is returned and no changes are made if 
      the name attribute is locked and component_name != locked value 
      or
      component_name is not empty and ON_ModelComponent::IsValidComponentName(component_name) is false.
  Remarks:
    If component_name is nullptr or the emtpy string, the NameIsSet() state will still be true.
  */
  bool SetName(
    const wchar_t* component_name
    );

  /*
  Description:
    Change the name of a component and optionally update a manifest.
  Parameters:
    new_name - [in]
      New name for the component.
    manifest - [in]
      nullptr or a manifest with an item for the component.
  */
  bool ChangeName(
    const wchar_t* new_name,
    class ON_ComponentManifest* manifest
  );

  /*
  Description:
    Set the component name value to the ON_ModelComponent::Unset.Name()
    and change the state so NameIsSet() and DeletedNameIsSet() both return false.
  */
  bool ClearName();

  /*
  Description:
    Calling LockName() will prohibit future changes to the Name attribute.
  */
  void LockName();

  /*
  Returns:
    True if the Name attribute is locked.
  */
  bool NameIsLocked() const;

  /*
  Returns:
    True if the name attribute is set.
  Remarks:
    At most one of NameIsSet() and DeletedNameIsSet() is true.
    A name can be set to the empty string.
  */
  bool NameIsSet() const;

  /*
  Returns:
    True if the deleted name attribute is set.
  Remarks:
    At most one of NameIsSet() and DeletedNameIsSet() is true.
  */
  bool DeletedNameIsSet() const;

  /*
  Description:
    If NameIsSet() is true, then the name is deleted in a waty that can be undone by calling UndeleteName() and
    the DeletedNameIsSet() property is changed to true.

    If NameIsSet() is false or NameIsLocked() is true, then nothing is changed.

    Note that a name can be set to the empty string and there is a difference between
    a name being set to the empty string and a name being unset.
    If you want to make the name attribute unset, call ClearName().
  */
  bool DeleteName();

  bool UndeleteName();

  void LockAllSettingsExceptName();
  bool SetLocalizedSystemComponentName(
    const wchar_t* system_component_localized_name
    );

  /*
  Parameters:
    other_name -[in]
  Returns:
    ON_wString::CompareAttributeName(this->Name(), other_name)
  Remarks:
    CompareName() is the correct tool to use when looking up objects by name.
  */
  int CompareName(
    const ON_UUID& other_parent_id,
    const wchar_t* other_name
    ) const;
  int CompareName(
    const wchar_t* other_name
    ) const;

  /*
  Parameters:
    other_name -[in]
  Returns:
    int rc = ON_wString::CompareAttributeName(this->Name(), other_name);
    return (0 != rc) ? rc : ON_wString::CompareOrdinal(this->Name(), other_name, false);
  Remarks:
    CompareNameExact() is the correct tool to use when detecting changes in
    case are important.  Use CompareName() when searching for components by name. 
  */
  int CompareNameExact(
    const ON_UUID& other_parent_id,
    const wchar_t* other_name
    ) const;
  int CompareNameExact(
    const wchar_t* other_name
    ) const;


  /*
  Parameters:
    a -[in]
    b -[in]
  Returns:
    ON_wString::CompareAttributeName(a.Name(), b.Name() )
  Remarks:
    CompareName() is the correct tool to use when looking up objects by name.
  */
  static int CompareName(
    const ON_ModelComponent& a,
    const ON_ModelComponent& b
    );

  /*
  Parameters:
    a -[in]
    b -[in]
  Returns:
    int rc = ON_wString::CompareAttributeName(a.Name(), b.Name());
    return (0 != rc) ? rc : ON_wString::CompareOrdinal(a.Name(), b.Name(), false);
  Remarks:
    CompareNameExact() is the correct tool to use when detecting changes in
    case are important.  Use CompareName() when searching for components by name. 
  */
  static int CompareNameExact(
    const ON_ModelComponent& a,
    const ON_ModelComponent& b
    );

  static int CompareId(
    const ON_ModelComponent& a,
    const ON_ModelComponent& b
    );

  /*
  Description 
    Call ON_ModelComponent::CompareName() and then ON_ModelComponent::CompareId().
    When used for sorting, will be sorted by name and then by id.
  */
  static int CompareNameAndId(
    const ON_ModelComponent& a,
    const ON_ModelComponent& b
    );

  /*
  Description 
    Call ON_ModelComponent::Id()and then ON_ModelComponent::CompareName().
    When used for sorting, will be sorted by id and then by name.
  */
  static int CompareIdAndName(
    const ON_ModelComponent& a,
    const ON_ModelComponent& b
    );

  /*
  Description:
    Set a component's id, name and index to the manifest_item values.
  Parameters:
    manifest_item - [in]
    manifest_name - [in]
    bSetId - [in]
      Set the component id to manifest_item.m_manifest_id.
    bSetParentId - [in]
      Use manifest_item.NameHash().ParentId()
    bSetName - [in]
      Set the component name to manifest_name.
    bSetIndex - [in]
      Set the component index to manifest_item.m_manifest_index.
  */
  bool SetIdentification(
    const class ON_ComponentManifestItem& manifest_item,
    const wchar_t* manifest_name,
    bool bSetId,
    bool bParentId,
    bool bSetName,
    bool bSetIndex
    );
  

  ///////////////////////////////////////////////////////////////////////////////
  //
  // General attributes interface
  //
  //

  /*
  Description:
    Writes the attributes identified by the component_filter parameter.
  Parameters:
    attributes_filter - [in]
      A bitfield that determines which attributes will be cleared.
  Returns:
    a bitfield indicating which attributes were cleared.
    (Locked attributes cannot be cleared.)
  */
  unsigned int ClearModelComponentAttributes(
    unsigned int attributes_filter
    );

  /*
  Returns:
    The runtime serial number.  
    This value is unique for every instance of an ON_ModelComponent class.  
    This value is never saved in .3dm archives.
  */
  ON__UINT64 RuntimeSerialNumber() const;

  /*
  Description:
    Whenever an attribute is changed, the content version number is incremented.
    The ContentVersionNumber() is commonly used by consumers of the model 
    component attributes to trigger updates when needed.
  Remarks:
    The ContentVersionNumber value is copied by the copy constructor and operator=.
    The value is not saved in .3dm archives.
  */
  ON__UINT64 ContentVersionNumber() const;

  /*
  Returns:
    True if this model component is a system constant.  
  Remarks:
    An incomplete list of system constant model compoenents is below:

      ON_ModelComponent::Unset

      ON_InstanceDefinition::Empty

      ON_Linetype::Unset
      ON_Linetype::Continuous
      ON_Linetype::ByLayer
      ON_Linetype::ByParent

      ON_Layer::Unset
      ON_Layer::Default

      ON_TextStyle::Unset
      ON_TextStyle::Default
      ON_TextStyle::ByLayer
      ON_TextStyle::ByParent

      ON_DimStyle::Unset
      ON_DimStyle::Default
      ON_DimStyle::DefaultInchDecimal
      ON_DimStyle::DefaultInchFractional
      ON_DimStyle::DefaultFootInchArchitecture
      ON_DimStyle::DefaultMillimeterSmall
      ON_DimStyle::DefaultMillimeterLarge
      ON_DimStyle::DefaultMillimeterArchitecture
  */
  bool IsSystemComponent() const;

  bool EraseIdentification(
    bool bIgnoreLocks
    );

  bool SetAsSystemComponent();
  bool SetAsUnsetSystemComponent();

private:
  bool Internal_SetAsSystemComponent(
    bool bUnsetSystemComponent
    );

protected:
  /*
    Classes derived from ON_ModelComponent should have private data members and
    call IncrementContentVersionNumber() when the data member value changes.
  */
  void IncrementContentVersionNumber() const;

private:
  const ON__UINT64 m_runtime_serial_number;  
  mutable ON__UINT64 m_content_version_number = 0;
  ON__UINT32 m_model_serial_number = 0;
  ON__UINT32 m_reference_model_serial_number = 0;
  ON__UINT32 m_linked_idef_serial_number = 0;
  ON_ModelComponent::Type m_component_type = ON_ModelComponent::Type::Unset;
 
  ON__UINT16 m_locked_status = 0;
  ON__UINT16 m_set_status = 0;
  ON_ComponentStatus m_component_status = ON_ComponentStatus::NoneSet;
  ON__UINT8 m_reserved1 = 0;
  ON__UINT16 m_reserved2 = 0;

  // m_component_index is the index of the component in the model identified 
  // by m_model_serial_number.
  //
  // Some components use small negative indices (-1,-2,-3,...) to identify
  // default or constant components.  An incomplete list includes these:
  //   ON_TextStyle::Default, (index = -1) 
  //   ON_TextStyle::ByLayer,  (index = -2) 
  //   ON_TextStyle::ByParent,  (index = -3) 
  //   ON_Linetype::Continuous,  (index = -1) 
  //   ON_Linetype::ByLayer,  (index = -2) 
  //   ON_Linetype::ByParent,  (index = -3) 
  //
  // ON_UNSET_INT_INDEX is a large negative number.
  ON__INT32 m_component_index = ON_UNSET_INT_INDEX;  
  ON__UINT32 m_reserved3 = 0;

  ON_UUID m_component_id = ON_nil_uuid;
  ON_UUID m_component_parent_id = ON_nil_uuid;
  // lazy evaluation is used top initialize m_component_name_hash
  mutable ON_NameHash m_component_name_hash;

  ON_wString m_component_name;

public:
  // For internal use.  Never call this function.
  static unsigned int Internal_SystemComponentHelper();
};


class ON_CLASS ON_ModelComponentContentMark
{
public:
  static const ON_ModelComponentContentMark Unset;
public:
  ON_ModelComponentContentMark() = default;
  ~ON_ModelComponentContentMark() = default;
  ON_ModelComponentContentMark(const ON_ModelComponentContentMark&) = default;
  ON_ModelComponentContentMark& operator=(const ON_ModelComponentContentMark&) = default;

  /*
  Description:
    Save the current content state of model_component.
  Parameters:
    model_component - [in]
  */
  ON_ModelComponentContentMark(
    const class ON_ModelComponent& model_component
  );

  /*
  Description:
    Save the current content state of model_component.
  Parameters:
    model_component - [in]
  */
  ON_ModelComponentContentMark(
    const class ON_ModelComponent* model_component
  );

  /*
  Description:
    Save the current content state of model_component.
  Parameters:
    model_component - [in]
  */
  void Set(
    const class ON_ModelComponent& model_component
  );

  /*
  Description:
    Save the current content state of model_component.
  Parameters:
    model_component - [in]
  */
  void Set(
    const class ON_ModelComponent* model_component
  );
  
  /*
  Parameters:
    model_component - [in]
  Returns:
    true if the content of model_component is identical
    to the content state saved in this ON_ModelComponentContentMark.
    false otherwise.
  */
  bool EqualContent(
    const class ON_ModelComponent& model_component
  ) const;
    
  /*
  Parameters:
    model_component - [in]
  Returns:
    true if the content of model_component is identical
    to the content state saved in this ON_ModelComponentContentMark.
    false otherwise.
  */
  bool EqualContent(
    const class ON_ModelComponent* model_component
  ) const;
  
  /*
  Parameters:
    lhs - [in]
    rhs - [in]
  Returns:
    true if lhs and rhs are identical.
    false otherwise.
  */
  static bool EqualContent(
    const ON_ModelComponentContentMark& lhs,
    const ON_ModelComponentContentMark& rhs
  );

  /*
  Returns:
    Saved model component id.
  */
  ON_UUID ComponentId() const;

  /*
  Returns:
    Saved model component runtime serial number.
  */
  ON__UINT64 ComponentRuntimeSerialNumber() const;

  /*
  Returns:
    Saved model component content version number.
  */
  ON__UINT64 ComponentContentVersionNumber() const;

  /*
  Returns:
    Saved model component type.
  */
  ON_ModelComponent::Type ComponentType() const;

  /*
  Returns:
    True if a model component content state is saved in this ON_ModelComponentContentMark.
    False otherwise.
  */
  bool IsSet() const;

  /*
  Returns:
    True if a model component content state is saved in this ON_ModelComponentContentMark.
    False otherwise.
  */
  bool IsUnset() const;

private:
  ON_UUID m_component_id = ON_nil_uuid;
  ON__UINT64 m_component_serial_number = 0;  
  ON__UINT64 m_component_content_version_number = 0;
  ON_ModelComponent::Type m_component_type = ON_ModelComponent::Type::Unset;

private:
  unsigned char m_reserved1 = 0;
  unsigned char m_reserved2 = 0;
  unsigned char m_reserved3 = 0;
  unsigned int m_reserved4 = 0;
};

bool operator==(
  const ON_ModelComponentContentMark& lhs,
  const ON_ModelComponentContentMark& rhs
  );

bool operator!=(
  const ON_ModelComponentContentMark& lhs,
  const ON_ModelComponentContentMark& rhs
  );

class ON_CLASS ON_ModelComponentTypeIterator
{
public:
  // Default constructor creates ON_ModelComponentTypeIterator::Empty
  ON_ModelComponentTypeIterator() ON_NOEXCEPT;

  ~ON_ModelComponentTypeIterator() = default;
  ON_ModelComponentTypeIterator(const ON_ModelComponentTypeIterator&) = default;
  ON_ModelComponentTypeIterator& operator=(const ON_ModelComponentTypeIterator&) = default;

  /*
  Paramters:
    type_count - [in] number of types
    types - [in]
      list of types to iterate over
  */
  ON_ModelComponentTypeIterator(
    size_t type_count,
    const ON_ModelComponent::Type* types
    ) ON_NOEXCEPT;
  
  // Contains no types
  static const ON_ModelComponentTypeIterator Empty;

  // Contains all explicit component types (excludes Unset and Mixed).
  static const ON_ModelComponentTypeIterator ExplicitComponentTypes;

  // Every type in ON_ModelComponentTypeIterator::ExplicitComponents
  // except Image, RenderLight, ModelGeometry, and HistoryRecord
  // The types in ON_ModelComponentTypeIterator::Tables
  // identify the most commonly used "table" component types.
  static const ON_ModelComponentTypeIterator TableComponentTypes;

  // Number of types in the iterator
  unsigned int TypeCount() const;

  /*
  Description:
    Sets the iterator to point to the first available type. 
  Returns:
    The first available type.
  */
  ON_ModelComponent::Type FirstType();

  /*
  Description:
    Sets the iterator to point to the last available type. 
  Returns:
    The last available type.
  */
  ON_ModelComponent::Type LastType();

  /*
  Description:
    Increments the iterator and returns the new type.
  Returns:
    The new type.
    ON_ModelComponent::Type::Unset if the iterator is incremented the last type.
  */
  ON_ModelComponent::Type NextType();
  
  /*
  Description:
    Decrements the iterator and returns the new type.
  Returns:
    The new type
    ON_ModelComponent::Type::Unset if the iterator is decrented the first type.
  */
  ON_ModelComponent::Type PreviousType();

  /*
  Description:
    Decrements the iterator and returns the new type.
  Returns:
    The current type.
  */
  ON_ModelComponent::Type CurrentType() const;

private:
  ON__INT32 m_type_count = 0;

  // -1 iterated before first, m_type_count = iteratated past last
  ON__INT32 m_current_index = ON_UNSET_UINT_INDEX; 

  ON_ModelComponent::Type m_types[32];
};

class ON_CLASS ON_ModelComponentReference
{
public:
  static const ON_ModelComponentReference Empty;
  
  // No = default to insure m_sp is completely managed in the openurbs DLL.
  ON_ModelComponentReference() ON_NOEXCEPT; // No = default to insure m_sp is completely managed in the openurbs DLL.
  ~ON_ModelComponentReference(); // No = default to insure m_sp is completely managed in the openurbs DLL.
  ON_ModelComponentReference(const ON_ModelComponentReference&) ON_NOEXCEPT; // No = default to insure m_sp is completely managed in the openurbs DLL.
  ON_ModelComponentReference& operator=(const ON_ModelComponentReference&); // No = default to insure m_sp is completely managed in the openurbs DLL.
  
#if defined(ON_HAS_RVALUEREF)
  ON_ModelComponentReference( ON_ModelComponentReference&& ) ON_NOEXCEPT;
  ON_ModelComponentReference& operator=( ON_ModelComponentReference&& );
#endif

  ON_ModelComponentReference(
    std::shared_ptr<ON_ModelComponent>& sp
    ) ON_NOEXCEPT;

  ON_ModelComponentReference& operator=(
    std::shared_ptr<ON_ModelComponent>& sp
    );
  
  /*
  Parameters:
    constant_system_component - [in]
      A constant system component that exists for the duration of 
      the application.
  Remarks:
    See ON_ModelComponent::CreateConstantSystemComponentReference()
    for more information about constant system components.

  */
  static ON_ModelComponentReference CreateConstantSystemComponentReference(
    const class ON_ModelComponent& constant_system_component
    ) ON_NOEXCEPT;

  /*
  Parameters:
    model_component - [in]
    bManagedComponentReference - [in]
      true
        model_component will be deleted by the last ON_ModelComponentReference
        and must have been created by call to operator new() with heap allocation.
      false 
        model_component must remain in scope until the last ON_ModelComponentReference
        is destroyed.
  Remarks:
    The input pointer will be managed and deleted by the returned
    by ON_ModelComponentReference.
  */
  static ON_ModelComponentReference CreateForExperts(
    class ON_ModelComponent* model_component,
    bool bManagedComponentReference
    ) ON_NOEXCEPT;

  /*
  Return:
    A pointer to the managed model component or nullptr.
  */
  const class ON_ModelComponent* ModelComponent() const ON_NOEXCEPT;

  ON__UINT64 ModelComponentRuntimeSerialNumber() const ON_NOEXCEPT;
  const ON_UUID ModelComponentId() const ON_NOEXCEPT;
  const ON_NameHash ModelComponentNameHash() const ON_NOEXCEPT;
  int ModelComponentIndex() const ON_NOEXCEPT;

  unsigned int ReferenceCount() const ON_NOEXCEPT;
  
  bool IsEmpty() const ON_NOEXCEPT;

  void Dump(
    ON_TextLog& text_log
    ) const;

private:
#pragma ON_PRAGMA_WARNING_PUSH
#pragma ON_PRAGMA_WARNING_DISABLE_MSC( 4251 ) 
  // C4251: ... needs to have dll-interface to be used by clients of class ...
  // m_sp is private and all code that manages m_sp is explicitly implemented in the DLL.
  std::shared_ptr<ON_ModelComponent> m_sp;
#pragma ON_PRAGMA_WARNING_POP
};

#if defined(ON_DLL_TEMPLATE)
ON_DLL_TEMPLATE template class ON_CLASS ON_ClassArray<ON_ModelComponentReference>;
#endif

#endif