# SPDX-License-Identifier: GPL-2.0-or-later
# CAP: Categories, Algorithms, Programming
#
# Implementations
#

######################################
##
## Reps, types, stuff.
##
######################################

# backwards compatibility
BindGlobal( "IsCapCategoryObjectRep", IsCapCategoryObject );

#######################################
##
## Technical implications
##
#######################################

InstallValue( PROPAGATION_LIST_FOR_EQUAL_OBJECTS, [ ] );

##
InstallGlobalFunction( INSTALL_TODO_LIST_FOR_EQUAL_OBJECTS,
                       
  function( object_1, object_2 )
    local category, i, entry;
    
    category := CapCategory( object_1 );
    
    for i in PROPAGATION_LIST_FOR_EQUAL_OBJECTS do
        
        AddToToDoList( ToDoListEntryForEqualAttributes( object_1, i, object_2, i ) );
        
    od;
    
    if IsBound( category!.PROPAGATION_LIST_FOR_EQUAL_OBJECTS ) then
        
        for i in category!.PROPAGATION_LIST_FOR_EQUAL_OBJECTS do
            
            AddToToDoList( ToDoListEntryForEqualAttributes( object_1, i, object_2, i ) );
            
        od;
        
    fi;
    
end );

##
InstallMethod( AddPropertyToMatchAtIsEqualForObjects,
               [ IsCapCategory, IsString ],
               
  function( category, name )
    
    if not IsBound( category!.PROPAGATION_LIST_FOR_EQUAL_OBJECTS ) then
        
        category!.PROPAGATION_LIST_FOR_EQUAL_OBJECTS := [ ];
        
    fi;
    
    if Position( category!.PROPAGATION_LIST_FOR_EQUAL_OBJECTS, name ) = fail then
        
        Add( category!.PROPAGATION_LIST_FOR_EQUAL_OBJECTS, name );
        
    fi;
    
end );

#######################################
##
## Operations
##
#######################################

InstallMethod( Add,
               [ IsCapCategory, IsCapCategoryObject ],
               
  function( category, object )
    local filter;
    
    filter := ObjectFilter( category );
    
    if not filter( object ) then
        
        SetFilterObj( object, filter );
        
    fi;
        
    if HasCapCategory( object ) then
        
        if IsIdenticalObj( CapCategory( object ), category ) then
            
            return;
            
        else
            
            Error(
                Concatenation(
                    "an object that lies in the CAP-category with the name\n",
                    Name( CapCategory( object ) ),
                    "\n",
                    "was tried to be added to a different CAP-category with the name\n",
                    Name( category ), ".\n",
                    "(Please note that it is possible for different CAP-categories to have the same name)"
                )
            );
            
        fi;
        
    fi;
    
    SetCapCategory( object, category );
    
end );

InstallMethod( AddObject,
               [ IsCapCategory, IsCapCategoryObject ],
               
  function( category, object )
    
    Add( category, object );
    
end );

InstallMethod( AddObject,
               [ IsCapCategory, IsAttributeStoringRep ],
               
  function( category, object )
    
    SetFilterObj( object, IsCapCategoryObject );
    
    Add( category, object );
    
end );

##
InstallGlobalFunction( CreateCapCategoryObjectWithAttributes,
                       
  function( category, additional_arguments_list... )
    local arg_list, obj;
    
    arg_list := Concatenation(
        [ category!.object_type, CapCategory, category ], additional_arguments_list
    );
    
    obj := CallFuncList( CreateGapObjectWithAttributes, arg_list );
    
    return obj;
    
end );

##
InstallGlobalFunction( AsCapCategoryObject,
                       
  function( category, object_datum )
    local object_datum_type, obj;
    
    object_datum_type := CAP_INTERNAL_GET_DATA_TYPE_FROM_STRING( "object_datum", category );
    
    if object_datum_type <> fail then
        
        CAP_INTERNAL_ASSERT_VALUE_IS_OF_TYPE_GETTER( object_datum_type, {} -> "the second argument of `AsCapCategoryObject`" )( object_datum );
        
    fi;
    
    obj := CreateGapObjectWithAttributes( category!.object_type, CapCategory, category, category!.object_attribute, object_datum );
    
    if not IsIdenticalObj( category!.object_attribute( obj ), object_datum ) then
        
        Print( "WARNING: <object_datum> is not identical to `", category!.object_attribute_name, "( <obj> )`. You might want to make <object_datum> immutable.\n" );
        
    fi;
    
    return obj;
    
end );

###########################
##
## Print
##
###########################

InstallMethod( String,
               [ IsCapCategoryObject ],
               
  function( object )
    
    return Concatenation( "An object in ", Name( CapCategory( object ) ) );
    
end );

# fallback methods for Julia
InstallMethod( ViewString,
               [ IsCapCategoryObject ],
               
  function ( object )
    
    # do not reuse `String` because objects might use `String` as the attribute storing the object datum
    return Concatenation( "<An object in ", Name( CapCategory( object ) ), ">" );
    
end );

InstallMethod( DisplayString,
               [ IsCapCategoryObject ],
               
  function ( object )
    
    # do not reuse `String` because objects might use `String` as the attribute storing the object datum
    return Concatenation( "An object in ", Name( CapCategory( object ) ), ".\n" );
    
end );

##
InstallGlobalFunction( CAP_INTERNAL_CREATE_OBJECT_PRINT,
                       
  function( )
    local print_graph, object_function;
    
    object_function := function( object )
      local string;
        
        string := "object in ";
        
        Append( string, Name( CapCategory( object ) ) );
        
        return string;
        
    end;
    
    print_graph := CreatePrintingGraph( IsCapCategoryObject and HasCapCategory, object_function );
    
    AddRelationToGraph( print_graph,
                        rec( Source := [ rec( Conditions := "IsZeroForObjects",
                                              PrintString := "zero",
                                              Adjective := true ) ],
                             Range := [ rec( Conditions := "IsInjective",
                                             PrintString := "injective",
                                             Adjective := true ),
                                        rec( Conditions := "IsProjective",
                                             PrintString := "projective",
                                             Adjective := true ) ] ) );
    
    
    InstallPrintFunctionsOutOfPrintingGraph( print_graph, -1 );
    
end );

#= comment for Julia
CAP_INTERNAL_CREATE_OBJECT_PRINT( );
# =#