--  Programmed by Jedidiah Barber
--  Licensed under the Sunset License v1.0

--  See license.txt for further details


private with

    Ada.Containers.Hashed_Maps,
    Ada.Containers.Vectors,
    Ada.Finalization;


generic
    Relation : in Goal;
    Within   : in State;
package Kompsos.Collector is


    State_Not_Found_Error : exception;


    function Has_Next
        return Boolean;

    function Next
        return State;

    function Next
           (Default : in State)
        return State;


private


    --  Interleaved Graph Inversion  --

    package Positive_Vectors is new Ada.Containers.Vectors
       (Index_Type   => Positive,
        Element_Type => Positive);

    subtype Disjuncts_Chosen is Positive_Vectors.Vector;

    function "<"
           (Left, Right : in Disjuncts_Chosen)
        return Boolean;

    type Parent_Arrow is record
        Node  : Graph_Component_Access;
        Order : Disjuncts_Chosen;
    end record;

    function "<"
           (Left, Right : in Parent_Arrow)
        return Boolean;

    package Parent_Arrow_Vectors is new Ada.Containers.Vectors
       (Index_Type   => Positive,
        Element_Type => Parent_Arrow);

    subtype Disjuncts_Passed is Natural;

    type Node_Upwards is record
        Depth   : Disjuncts_Passed;
        Parents : Parent_Arrow_Vectors.Vector;
    end record;

    package Upwards_Vectors is new Ada.Containers.Vectors
       (Index_Type   => Positive,
        Element_Type => Node_Upwards);

    function Graph_Component_Access_Hash
           (Key : in Graph_Component_Access)
        return Ada.Containers.Hash_Type;

    package Upwards_Maps is new Ada.Containers.Hashed_Maps
       (Key_Type        => Graph_Component_Access,
        Element_Type    => Positive,
        Hash            => Graph_Component_Access_Hash,
        Equivalent_Keys => "=");


    --  Conjunct Expansion  --

    type Goal_Access is access all Goal;

    package Goal_Access_Vectors is new Ada.Containers.Vectors
       (Index_Type   => Positive,
        Element_Type => Goal_Access);


    --  Upwards Depth First Search  --

    type Breadcrumb is record
        Choice_Node : Graph_Component_Access;
        Option      : Positive;
        State_Size  : Long_Natural;
    end record;

    package Breadcrumb_Vectors is new Ada.Containers.Vectors
       (Index_Type   => Positive,
        Element_Type => Breadcrumb);


    --  Cleanup  --

    type Collector_Final_Controller is new Ada.Finalization.Limited_Controlled with null record;

    overriding procedure Finalize
           (This : in out Collector_Final_Controller);

    Cleanup : Collector_Final_Controller;


end Kompsos.Collector;