-- File graphtrv.adb
--  This is a program that instantiates and populates a graph, in
--  response to commands input from a data file.  Some of those
--  commands require either a depth-first or breadth-first traversal of
--  the graph.  The program uses both a stack and a queue as auxiliary
--  data structures to implement those traversals.

with text_io, stackg, queueg, graphg;
use text_io;

procedure graphtrv is
   package my_graph is new graphg (integer);
   use my_graph;

   Package IntIO is new Integer_IO (integer);
   use IntIO;

   package graph_stack is new stackg (Iterator);
   use graph_stack;

   package graph_queue is new queueg (Iterator);
   use graph_queue;

   IntGraph: Graph (25);

   InData,
   OutData: File_Type;
   Cmd: Character;

   procedure AddNode (InGraph: in out Graph) is
      number, value: integer;
      begin
         Get (InData, number);
         Get (InData, value);
         Add (number, value, InGraph);
         Put (OutData, "  Added node number ");
         Put (OutData, number);
         Put (OutData, "  with value ");
         Put (OutData, value);
         New_Line (OutData);
      end AddNode;

   procedure AddEdge (InGraph: in out Graph) is
      from, to: integer;
      begin
         Get (InData, from);
         Get (InData, to);
         InsertEdge (from, to, InGraph);
         Put (OutData, "  Added an edge from node ");
         Put (OutData, from);
         Put (OutData, "  to node ");
         Put (OutData, to);
         New_Line (OutData);
      end AddEdge;

   procedure Breadth (OfGraph: in out Graph) is
      IStack: Stack;
      start: integer;
      curnode, temp: Iterator;
      begin
         Clear (IStack);
         Get (InData, start);
         Put (OutData, "  Starting breadth-first traversal from node ");
         Put (OutData, start);
         New_Line (OutData);
         Initialize (curnode, OfGraph, start);
         Push (curnode, IStack);
         while not Empty (IStack) loop
            Put ("Halt - press Return");
            Skip_Line;
            curnode := Top (IStack);
            Pop (IStack);
            Put (OutData, "    Visit node with value ");
            Put (OutData, ValueOf (curnode, OfGraph));
            New_Line (OutData);
            temp := curnode;
            while not Done (curnode, OfGraph) loop
               GetNext (temp, OfGraph);
               Push (temp, IStack);
            end loop;
         end loop;
      end Breadth;

   procedure Depth (OfGraph: in out Graph) is
      IQueue: Queue;
      start: integer;
      curnode, temp: Iterator;
      begin
         Clear (IQueue);
         Get (InData, start);
         Put (OutData, "  Starting depth-first traversal from node ");
         Put (OutData, start);
         New_Line (OutData);
         Initialize (curnode, OfGraph, start);
         Add (curnode, IQueue);
         while not Empty (IQueue) loop
            Put ("Halt - press Return");
            Skip_Line;
            curnode := First (IQueue);
            Pop (IQueue);
            Put (OutData, "    Visit node with value ");
            Put (OutData, ValueOf (curnode, OfGraph));
            New_Line (OutData);
            temp := curnode;
            while not Done (curnode, OfGraph) loop
               GetNext (temp, OfGraph);
               Add (temp, IQueue);
            end loop;
         end loop;
      end Depth;

   begin
      open (InData, IN_FILE, "graphtrv.dat");
      open (OutData, OUT_FILE, "graphtrv.out");

      Clear (IntGraph);

      Put (OutData, "*** Beginning to process command data file ***");
      New_Line (OutData);
      while not End_Of_File (InData) loop
         get (InData, Cmd);
         case Cmd is
            when 'N' => AddNode (IntGraph);
            when 'E' => AddEdge (IntGraph);
            when 'B' => Breadth (IntGraph);
            when 'D' => Depth (IntGraph);
            when others => null;
         end case;
         Skip_Line (InData);
      end loop;
      Put (OutData, "*** Done processing command data file ***");
      New_Line (OutData);
   end graphtrv;