-- Assignment 1.
-- Eugene Burke
-- Oct 23, 1996
--
-- FILE:
--       life_game.adb
--       is used by life_game.ads, life1.adb

-- PURPOSE:
--       Implements the functions of the Life board


with Ada.Text_IO;
with Ada.Integer_Text_IO; 
 
package body Life_Game is

function Neighbor_Count (I : ROW; J  : COL; Map : GRID) return INTEGER is
  Count : INTEGER;
  
  Xlow	:	ROW;
  Xhigh	:	ROW;
  Ylow	:	COL;
  Yhigh	:	COL;

begin
  if I = 1 then
    Xlow := 1;
  else
    Xlow := I-1;
  end if;

  if I = MaxRow then
    Xhigh := 1;
  else
    Xhigh := I+1;
  end if;

  if J = 1 then
    Ylow := 1;
  else
    Ylow := J-1;
  end if;

  if J = MaxCol then
    Yhigh := 1;
  else
    Yhigh := J+1;
  end if;

  Count := 0;

  for X in Xlow..Xhigh loop
    for Y in Ylow..Yhigh loop
      if Map(X,Y) = alive then
        Count := Count + 1;
      end if;
    end loop;
  end loop;
  if Map(I,J) = alive then
    Count := Count - 1;
  end if;
  return Count;
end Neighbor_Count;

procedure Initialize (Map : out GRID) is

  X	:	INTEGER;
  Y	:	INTEGER;

begin
  Ada.Text_IO.Put (Item => "This program is a simulation of Game of Life");
  Ada.Text_IO.New_Line;
  for X in 1..MaxRow loop
    for Y in 1..MaxCol loop
      Map(X,Y) := dead;
    end loop;
  end loop;

  Ada.Text_IO.Put(Item => "On each line give a pair of");  
  Ada.Text_IO.Put(Item => " coordinates for a living cell");
  Ada.Text_IO.New_Line;
  Ada.Text_IO.Put(Item => "Terminate the list with the special pair 0 0");
  Ada.Text_IO.New_Line;
  Ada.Integer_Text_IO.Get(Item => X);
  Ada.Integer_Text_IO.Get(Item => Y);
  while (X /= 0 or Y /= 0) loop
    if (X >= 1 and X <= MaxRow and Y >= 1 and Y <= MaxCol) then
      Map(X,Y) := alive;
    else
      Ada.Text_IO.Put(Item => "Values are not within range");
      Ada.Text_IO.New_Line;
    end if;
    Ada.Integer_Text_IO.Get(Item => X);
    Ada.Integer_Text_IO.Get(Item => Y);
  end loop;
end Initialize;

procedure Write_Map (Map :  in GRID) is
 
  Full	: constant character := '*';
  Empty : constant character := ' ';

  --X	:	ROW;
  --Y	:	COL;

begin
  Ada.Text_IO.Put(Item => "The map is below");
  Ada.Text_IO.New_Line;

  for X in 1..MaxRow loop
    for Y in 1..MaxCol loop
      if Map(X,Y) = alive then
        Ada.Text_IO.Put(Item => Full);
      else
        Ada.Text_IO.Put(Item => Empty);
      end if;
    end loop;
    Ada.Text_IO.New_Line;
  end loop;
end Write_Map;

function Enquire return BOOLEAN is
 
  Run_again	:	BOOLEAN;
  Response	:	Character;

begin
  while Response /= 'Y' and Response /= 'y' and 
        Response /= 'N' and Response /= 'n' loop
    Ada.Text_IO.Put (Item => "Continue (y / n)");
    Ada.Text_IO.New_Line;
    Ada.Text_IO.Get (Item => Response);
  end loop;

  if Response ='Y' or Response = 'y' then
    Run_Again := true;
  else
    Run_Again := false;
  end if;
  
  return Run_Again;
end Enquire;

end Life_Game;

-- COMMENTS
-- You are very lucky.  You can change the board by placing
-- a border of dead cells around it, to avoid checking for boundary
-- conditions, and only this implementation
-- must be changed.  Your other two files can remain the same.
-- Isn't that a nice feature of modularity.
-- The only cost of adding a border is the initialization of the
-- temporary grid that is used to store the next generation, which
-- can be done in the declaration:
--     Map : GRID := (others => (others => FALSE));

-- Loop parameters cannot be explicitly declared.  In fact, you will
-- be allocated  different variables X and Y than your loop parameters.
-- I would also prefer the names Row and Column to X and Y.