Unit moversProc;

Interface

Uses dataUnit;

Procedure moveMovers(Var g: GameState);

Implementation

Function turnMover(c: char; d: integer): char;

Const 
  period = ord(high(TMoverDir))+1;

Var 
  j, x: integer;
  i : TMoverType;
Begin
  For i := low(TMoverType) To high(TMoverType) Do
    For j := ord(low(TMoverDir)) To ord(high(TMoverDir)) Do
      If c = movers[i, TMoverDir(j)] Then
        Begin
          x := (j+d) Mod period;
          Exit(movers[i, TMoverDir(x)]);
        End;
  Exit(c);
End;

Procedure rotateStep(Var rstep, cstep: integer; clockWise: boolean);
Begin
  cstep := cstep + rstep;
  rstep := cstep - rstep;
  cstep := cstep - rstep;
  If clockWise Then
    cstep := -cstep
  Else
    rstep := -rstep;
End;

Procedure moveMover(Var g: GameState; row, col, rstep, cstep: integer);

Var 
  rns : integer = 0;
  cns : integer = 0;
Begin

  (* I don't move if I'm cought by a magnet *)
  If (rstep <> 0) And (g.map[row - rstep, col] = magnety) Then Exit;
  If (cstep <> 0) And (g.map[row, col - cstep] = magnetx) Then Exit;

  (* I don't move beyond the map *)
  If (col + cstep > g.mapWidth) Or (col + cstep < 1) Or
     (row + rstep > g.mapHeight) Or (row + rstep < 1) Then
    Begin
      If g.map[row,col] In pushers Then
        g.map[row, col] := turnMover(g.map[row,col], 2);
      Exit;
    End;

  (* Turners turn me *)
  Case g.map[row + rstep, col + cstep] Of 
    'a':
         Begin
           g.map[row, col] := turnMover(g.map[row,col], 1);
           rotateStep(rstep, cstep, True);
         End;
    'c':
         Begin
           g.map[row, col] := turnMover(g.map[row,col], -1);
           rotateStep(rstep, cstep, False);
         End;
  End;

  (* Simple movement *)
  If g.map[row + rstep, col + cstep] = empty Then
    Begin
      g.map[row + rstep, col + cstep] := g.map[row,col];
      g.map[row, col] := empty;
      Exit;
    End;


  (* Pushers turn around and push pushables *)
  If (g.map[row,col] In pushers) Then
    Begin
      If (g.map[row + rstep, col + cstep] In pushable) And
         (g.map[row + 2 * rstep, col + 2 * cstep] = empty) Then
        Begin
          g.map[row + 2 * rstep, col + 2 * cstep] := g.map[row + rstep, col + cstep];
          g.map[row + rstep, col + cstep] := empty;
        End;
      g.map[row, col] := turnMover(g.map[row,col], 2);
      Exit;
    End;

  (* Gliders slip on slipery things*)
  If (g.map[row,col] In gliders) And
     (g.map[row + rstep, col + cstep] In slipery) Then
    Begin
      If cstep <> 0 Then
        rns := 2 * random(1) - 1
      Else
        cns := 2 * random(1) - 1;

      If (g.map[row + rns, col + cns] = empty) And
         (g.map[row + rstep + rns, col + cstep + cns] = empty) Then
        Begin
          g.map[row + rstep + rns, col + cstep + cns] := g.map[row,col];
          g.map[row, col] := empty;
        End
      Else If (g.map[row - rns, col - cns] = empty) And
              (g.map[row + rstep - rns, col + cstep - cns] = empty) Then
             Begin
               g.map[row + rstep - rns, col + cstep - cns] := g.map[row,col];
               g.map[row, col] := empty;
             End;
    End;
End;

Procedure moveMovers(Var g: GameState);

Var 
  idx, row, col, Width, Height: integer;
Begin
  Width := g.mapWidth;
  Height := g.mapHeight;
  For idx := 0 To Height * Width - 1 Do
    Begin
    (* for up movers *)
      row := idx Div Width + 1;
      col := idx Mod Width + 1;
      If (g.map[row, col] In UpMovers) Then
        moveMover(g, row, col, -1, 0);
    (* for left movers *)
      col := idx Div Height + 1;
      row := idx Mod Height + 1;
      If (g.map[row, col] In LeftMovers) Then
        moveMover(g, row, col, 0, -1);
    (* for down movers *)
      row := Height - idx Div Width + 1;
      col := Width - idx Mod Width + 1;
      If (g.map[row, col] In DownMovers) Then
        moveMover(g, row, col, 1, 0);
    (* for Right movers *)
      col := Width - idx Div Height + 1;
      row := Height - idx Mod Height + 1;
      If (g.map[row, col] In RightMovers) Then
        moveMover(g, row, col, 0, 1);
    End;
End;

End.