program finalfinalbattleships;

uses
    SysUtils, StrUtils;

type
    TShipData = array [1..4] of integer; // x | y | v | t
    TCoordSet = array [0..5,1..2] of integer;
    TGrid = array [1..10, 1..10] of integer;

var
   grids : array[1..2,1..2] of TGrid;
   currentply : integer;

procedure printTitle(); // prints 'BATTLESHIPS: ' (GUI).
var
   n : integer;
begin
  writeln();
  writeln( 'BATTLESHIPS by Stuart Ashforth' );
  writeln( '------------------------------' );
  for n := 1 to 19 do
      writeln();

  writeln( 'Press enter to continue! ' );
  writeln();
  readln();
  writeln();

end;

procedure clearWindow(); // clears the window, avoiding cheating.
var
   k : integer;
begin
  for k := 1 to 100 do
      writeln();
end;

procedure clearAllGrids(); // sets the 'board' to empty.
var
   x, y, k : integer;
   grid : TGrid;
begin

  for k := 1 to 4 do
      begin

      case k of
      1 : grid := grids[1,1];
      2 : grid := grids[1,2];
      3 : grid := grids[2,1];
      4 : grid := grids[2,2];
      end;

      for y := 1 to 10 do
          begin
          for x := 1 to 10 do
              grid[x,y] := 0;
          end;
      end;
end;

function getSymbol( val : integer) : string; // changes data to symbols (GUI).
var
   sym : string;
begin
  case val of
  0 : sym := ' ';
  -1 : sym := 'x';
  -2 : sym := 'o';
  1 : sym := '&';
  2 : sym := '/';
  3 : sym := '=';
  4 : sym := '+';
  5 : sym := '%';
  6 : sym := '&';
  7 : sym := '/';
  8 : sym := '=';
  9 : sym := '+';
  10 : sym := '%';
  end;
  if sym = '' then sym := intToStr(val);
  sym := sym + ' ';
  getSymbol := sym;
end;

function getGrid( ship : TShipData ) : TGrid; // gets the grid a ship should be on.
var
   id : integer;
begin
  id := ship[4];

  if id <= 5 then
     getGrid := grids[1,1]
  else
      getGrid := grids[2,1];
end;

function getPly( ship : TShipData ) : integer; // gets the player a ship belongs to.
var
   id : integer;
begin
  id := ship[4];

  if id <= 5 then
     getPly := 1
  else
      getPly := 2;
end;

function idToLength( id : integer ) : integer; // converts a shipID to the length of a ship.
var
   length : integer;
begin
  case id of

  1 : length := 2;
  2 : length := 3;
  3 : length := 3;
  4 : length := 4;
  5 : length := 5;

  6 : length := 2;
  7 : length := 3;
  8 : length := 3;
  9 : length := 4;
  10 : length := 5;

  end;

  idToLength := length;
end;

procedure listGrid( ply : integer ); // lists a specific player's board (GUI).
var
   x, y, c : integer;
   sym : string;

begin

  writeln( '--------------------------------------------------' );
  writeln( '|    | A B C D E F G H I J | A B C D E F G H I J |' );
  writeln( '--------------------------------------------------' );

  for y := 1 to 9 do
      begin
      write( '| ',y,'  | ' );
      for x := 1 to 10 do
          begin
          c := grids[ply,1][x,y];
          sym := getSymbol( c );
          write( sym );
          end;
      write( '| ' );
      for x := 1 to 10 do
          begin
          c := grids[ply,2][x,y];
          sym := getSymbol( c );
          write( sym );
          end;
      writeln( '|');

      end;


  write( '| 10 | ' );
  for x := 1 to 10 do
          begin
          c := grids[ply,1][x,10];
          sym := getSymbol( c );
          write( sym );
          end;
  write( '| ' );
  for x := 1 to 10 do
      begin
      c := grids[ply,2][x,10];
      sym := getSymbol( c );
      write( sym );
      end;

  writeln( '|' );
  writeln( '--------------------------------------------------' );
  writeln( '| & : destroyer   + : battleship   / : submarine |' );
  writeln( '| = : cruiser     % : carrier      o : miss      |' );
  writeln( '|                                  x : hit       |' );
  writeln( '--------------------------------------------------' );
end;

function createShipData( x, y, v, id : integer ) : TShipData; // composes a TShipData array from its integer parts.
var
   ship : TShipData;
begin
  ship[1] := x;
  ship[2] := y;
  ship[3] := v;
  ship[4] := id;
  createShipData := ship;
end;

function boolStrToInt( str : string ) : integer; // converts y/n to true/false.
begin
  if str = 'y' then
     boolStrToInt := 1
  else
      boolStrToInt := 0;
end;

function getCoords( ship : TShipData ) : TCoordSet; // gets the set of coordinates corresponding to a particular ship.
var
   x,y, length, k : integer;
   coords : TCoordSet;
   v : boolean;
begin

  length := idToLength( ship[4] );

  x := ship[1];
  y := ship[2];
  v := (ship[3] = 1);
  coords[0,1] := length;

  if v then
     begin
     for k := 1 to length do
         begin
         coords[k,1] := x;
         coords[k,2] := y + k - 1;
         end;
     end
  else
      begin
      for k := 1 to length do
          begin
          coords[k,1] := x + k - 1;
          coords[k,2] := y;
          end;
      end;

  getCoords := coords;

end;

procedure createShip( ship : TShipData); // actually places the ship on its grid.
var
   coords : TCoordSet;
   length, id, k, x, y, ply : integer;
begin

  coords := getCoords( ship );
  ply := getPly( ship );
  length := coords[0,1];
  id := ship[4];

  for k := 1 to length do
      begin
      x := coords[k,1];
      y := coords[k,2];
      grids[ply,1][x,y] := id;
      end;
end;

function checkCoords( ship : TShipData ) : boolean; // checks to see if a ship has valid coordinates.
var
   grid : TGrid;
   coords : TCoordSet;
   x,y, k, length : integer;
   valid : boolean;

begin

  grid := getGrid( ship );
  coords := getCoords( ship );
  length := coords[0,1];
  valid := true;

  for k := 1 to length do
      begin
      x := coords[k,1];
      y := coords[k,2];

      if valid and ((x > 10) or (x < 1) or (y > 10) or (y < 1)) then
         begin
         valid := false;
         writeln();
         writeln( 'Error: proposed ship is outside the grid!' );
         writeln();
         end;

      if valid and ( not( grid[x,y] = 0 ) ) then
         begin
         valid := false;
         writeln();
         writeln( 'Error: proposed ship intersects with an existing one!' );
         writeln();
         end;
      end;

  checkCoords := valid;

end;

function checkValidFormat( inputStr : string ) : boolean; // checks to see if input is like 'A9'.
var
   valid : boolean;
   xstr, ystr : string;
   y : integer;
begin
  valid := true;
  if length( inputStr ) = 2 then
     begin
     xstr := inputStr[1];
     ystr := inputStr[2];
     end
  else
      if length( inputStr ) = 3 then
         begin
         xstr := inputStr[1];
         ystr := rightStr( inputStr, 2 );
         end;

  try y := strToInt( ystr );
  except
    valid := false;
  end;

  if (y < 1) or (y > 10) then
     valid := false;

  if valid then
     begin

     valid := false;

     if xstr = 'A' then valid := true;
     if xstr = 'B' then valid := true;
     if xstr = 'C' then valid := true;
     if xstr = 'D' then valid := true;
     if xstr = 'E' then valid := true;
     if xstr = 'F' then valid := true;
     if xstr = 'G' then valid := true;
     if xstr = 'H' then valid := true;
     if xstr = 'I' then valid := true;
     if xstr = 'J' then valid := true;
     if xstr = 'a' then valid := true;
     if xstr = 'b' then valid := true;
     if xstr = 'c' then valid := true;
     if xstr = 'd' then valid := true;
     if xstr = 'e' then valid := true;
     if xstr = 'f' then valid := true;
     if xstr = 'g' then valid := true;
     if xstr = 'h' then valid := true;
     if xstr = 'i' then valid := true;
     if xstr = 'j' then valid := true;

     end;

  checkValidFormat := valid;

end;

function stripX( inputStr : string ) : integer; // returns the x coordinate from e.g. 'A9'.
var
   x : integer;
   xstr : string;
begin
     xstr := inputStr[1];
     if xstr = 'A' then x := 1;
     if xstr = 'B' then x := 2;
     if xstr = 'C' then x := 3;
     if xstr = 'D' then x := 4;
     if xstr = 'E' then x := 5;
     if xstr = 'F' then x := 6;
     if xstr = 'G' then x := 7;
     if xstr = 'H' then x := 8;
     if xstr = 'I' then x := 9;
     if xstr = 'J' then x := 10;
     if xstr = 'a' then x := 1;
     if xstr = 'b' then x := 2;
     if xstr = 'c' then x := 3;
     if xstr = 'd' then x := 4;
     if xstr = 'e' then x := 5;
     if xstr = 'f' then x := 6;
     if xstr = 'g' then x := 7;
     if xstr = 'h' then x := 8;
     if xstr = 'i' then x := 9;
     if xstr = 'j' then x := 10;
     stripX := x;
end;

function stripY( inputStr : string ) : integer; // returns the y coordinate from e.g. 'A9'.
var
   y : integer;
begin
  if length(inputStr) = 2 then
     y := strToInt( inputStr[2] );
  if length(inputStr) = 3 then
     y := strToInt( rightStr(inputStr, 2) );
  stripY := y;
end;

function idToBoatName( id : integer ) : string; // returns the ship name (e.g. 'destroyer) from a shipID.
var
   name : string;
begin

  id := ((id - 1) mod 5) + 1;

  if id = 1 then name := 'destroyer';
  if id = 2 then name := 'submarine';
  if id = 3 then name := 'cruiser';
  if id = 4 then name := 'battleship';
  if id = 5 then name := 'carrier';

  idToBoatName := name;
end;

procedure inputBoat ( id : integer ); // gets player input for a ship of a particular shipID.

var
   x,y,v : integer;
   boatname, vstr, inputStr : string;
   valid : boolean;
   ship : TShipData;

begin
  repeat
  boatname := idToBoatName( id );
  write( 'Top left coordinate of your ',boatname, ': ');
  readln( inputStr );
  valid := true;

  if checkValidFormat( inputStr ) then
     begin
     x := stripX( inputStr );
     y := stripY( inputStr );
     end
  else
      begin
      writeln();
      writeln( 'That is not a valid coordinate! Example coordinate: A9' );
      writeln();
      valid := false;
      end;

  if valid then
     begin
     write( 'Place ship vertically? (y/n): ' );
     readln( vstr );
     v := boolStrToInt( vstr );
     ship := createShipData( x, y, v, id );
     valid := checkCoords( ship );

     end;

  until valid;

  createShip( ship );
end;

procedure setupTitle( ply : integer ); // prints 'Player 1 Setup' (GUI).
begin
     writeln( '----------------' );
     writeln( 'Player ',ply,' set up:' );
     writeln( '----------------' );
     writeln();
end;

procedure playerSetUp( ply : integer ); // gets a player to put his/her ships down.
var
   n : integer;
begin

  setUpTitle( ply );
  listGrid( ply );

  for n := (((ply-1)*5) + 1) to (((ply-1)*5) + 5) do
      begin
      writeln();
      inputBoat( n );
      writeln();
      setupTitle( ply );
      listGrid( ply );
      end;

end;

function otherPly( ply : integer ) : integer; // returns the player that isn't the current one.
begin
  otherPly := ( ply mod 2) + 1;
end;

procedure turnTitle( ply : integer ); // prints 'Player 1's turn' (GUI).
begin
     writeln( '----------------' );
     writeln( 'Player ',ply,'''s turn:' );
     writeln( '----------------' );
     writeln();
end;

procedure nextPlayerWait(); // the set processes that switch from one player's turn to the other's.
var
   nextPly : integer;
begin
  nextPly := otherPly( currentPly );
  writeln();
  writeln( 'Player ',nextPly,'''s turn! Press enter to continue!' );
  writeln();
  readln();
  clearWindow();
  writeln( 'Player ',nextPly,' are you ready? Press enter to continue!' );
  writeln();
  readln();
  currentPly := nextPly;
end;

function validMove( x, y, ply : integer) : boolean;
var
   valid : boolean;
begin

  valid := true;

  if ((x > 10) or (x < 1) or (y > 10) or (y < 1)) then
         begin
         valid := false;
         writeln();
         writeln( 'Error: proposed target is outside the grid!' );
         writeln();
         end;
  if valid and (not(grids[ply,2][x][y] = 0)) then
         begin
         valid := false;
         writeln();
         writeln( 'Error: target has already been tried!' );
         writeln();
         end;

  validMove := valid;
end;

procedure execMove( x, y, ply : integer);
var
   hit : boolean;
begin

  hit := false;

  if grids[otherPly(ply),1][x,y] > 0 then
     begin
     grids[otherPly(ply),1][x,y] := -1;
     grids[ply,2][x,y] := -1;
     hit := true;
     end
  else
      grids[ply,2][x,y] := -2;

  turnTitle( ply );
  listGrid( ply );
  if hit then
     begin
     writeln();
     writeln( 'You hit player ',otherPly(ply),'''s ship!' );
     writeln();
     end
  else
      begin
      writeln();
      writeln( 'That was a miss.' );
      writeln();
      end;

end;

procedure inputGo( ply : integer);
var
   x, y : integer;
   inputStr: string;
   valid : boolean;
begin

  turnTitle( ply );
  listGrid( ply );
  writeln();

  repeat

  valid := true;
  write( 'Desired coordinate of attack: ' );
  readln( inputStr );

  if checkValidFormat( inputStr ) then
     begin
     x := stripX( inputStr );
     y := stripY( inputStr );
     end
  else
      begin
      writeln();
      writeln( 'That is not a valid coordinate!' );
      writeln();
      valid := false;
      end;

  if valid then
     valid := validMove( x, y, ply );

  until valid;

  execMove( x, y, ply );

end;

function getPiecesLeft( ply: integer ) : integer;
var
   grid : TGrid;
   x,y, count : integer;
begin
  grid := grids[ply,1];
  count := 0;

  for y := 1 to 10 do
      for x := 1 to 10 do
          begin
          if grid[x,y] > 0 then
             count := count + 1;
          end;
  getPiecesLeft := count;
end;

begin

  printTitle();
  clearAllGrids();

  currentPly := 1;

  playerSetUp( currentPly ); // set up player 1
  nextPlayerWait();

  playerSetUp( currentPly ); // set up player 2
  nextPlayerWait();

  repeat

  inputGo( currentPly );

  if getPiecesLeft( otherPly( currentPly ) ) = 0 then
     begin
     writeln();
     writeln( 'Congratulations! Player ',currentPly,' has won! :D' );
     writeln();
     currentPly := otherPly( currentPly );
     end
  else
      nextPlayerWait();

  until getPiecesLeft( currentPly ) = 0;

  writeln( 'Game over!' );
  readln()
end.