/******************************************************
Original:  Jason Hotchkiss (jasonhotchkiss@home.com)
Web Site:  http://www.members.home.com/jasonhotchkiss

This script and many more are available free online at
The JavaScript Source!! http://javascript.internet.com
******************************************************/

// Begin

// Information used to draw the ships
var ship =  [[[1,5], [1,2,5], [1,2,3,5], [1,2,3,4,5]], [[6,10], [6,7,10], [6,7,8,10], [6,7,8,9,10]]];

// Information used to draw sunk ships
var dead = [[[201,203], [201,202,203], [201,202,202,203], [201,202,202,202,203]], [[204,206], [204,205,206], [204,205,205,206], [204,205,205,205,206]]];

// Information used to describe ships
var shiptypes = [["miinanraivaajan",2,4],["fregatin",3,4],[ "risteilyaluksen",4,2],[ "taistelulaivan",5,1]];

var gridx = 16, gridy = 16;
var player = [], computer = [], playersships = [], computersships = [];
var playerlives = 0, computerlives = 0, playflag=true, statusmsg="";

// Function to preload all the images, to prevent delays during play
var preloaded = [];
function imagePreload()
{
  var i,ids = [1,2,3,4,5,6,7,8,9,10,100,101,102,103,201,202,203,204,205,206];
  window.status = "Tuodaan kuvat...odota";
  for (i=0;i<ids.length;++i)
  {
    var img = new Image, name = "batt"+ids[i]+".gif";
    img.src = name;
    preloaded[i] = img;
  }
  window.status = "";
}

// Function to place the ships in the grid
function setupPlayer(ispc)
{
  var y,x;
  grid = [];
  for (y=0;y<gridx;++y)
  {
    grid[y] = [];
    for (x=0;x<gridx;++x)
    grid[y][x] = [100,-1,0];
  }
  
  var shipno = 0;
  var s;
  for (s=shiptypes.length-1;s>=0;--s)
  {
    var i;
    for (i=0;i<shiptypes[s][2];++i)
    {
      var d = Math.floor(Math.random()*2);
      var len = shiptypes[s][1], lx=gridx, ly=gridy, dx=0, dy=0;
      if (d==0)
      {
        lx = gridx-len;
        dx=1;
      }
      else
      {
        ly = gridy-len;
        dy=1;
      }
      var x,y,ok;
      do
      {
        y = Math.floor(Math.random()*ly);
        x = Math.floor(Math.random()*lx);
        var j,cx=x,cy=y;
        ok = true;
        for (j=0;j<len;++j)
        {
          if (grid[cy][cx][0] < 100)
          {
            ok=false;
            break;
          }
          cx+=dx;
          cy+=dy;
        }
      }
      while(!ok);
      var j,cx=x,cy=y;
      for (j=0; j<len; ++j)
      {
        grid[cy][cx][0] = ship[d][s][j];
        grid[cy][cx][1] = shipno;
        grid[cy][cx][2] = dead[d][s][j];
        cx+=dx;
        cy+=dy;
      }
      if (ispc)
      {
        computersships[shipno] = [s,shiptypes[s][1]];
        computerlives++;
      }
      else
      {
        playersships[shipno] = [s,shiptypes[s][1]];
        playerlives++;
      }
      shipno++;
    }
  }
  return grid;
}

// Function to change an image shown on a grid
function setImage(y,x,id,ispc)
{
  if (ispc)
  {
    computer[y][x][0] = id;
    document.images["pc"+y+"_"+x].src = "batt"+id+".gif";
  }
  else
  {
    player[y][x][0] = id;
    document.images["ply"+y+"_"+x].src = "batt"+id+".gif";
  }
}

// Function to insert HTML source for a grid
function showGrid(ispc)
{
  var y,x;
  for (y=0;y<gridy;++y)
  {
    for (x=0;x<gridx;++x)
    {
      if (ispc)
      document.write ('<a href="javascript:gridClick('+y+','+x+');"><img name="pc'+y+'_'+x+'" src="batt100.gif" width="16" height="16" class="whiteborder"></a>');
      else
      document.write ('<a href="javascript:void(0);"><img name="ply'+y+'_'+x+'" src="batt'+player[y][x][0]+'.gif" width="16" height="16" class="whiteborder"></a>');
    }
    document.write('<br />');
  }
}

// Handler for clicking on the grid
function gridClick(y,x)
{
  if (playflag)
  {
    if (computer[y][x][0] < 100)
    {
      setImage(y,x,103,true);
      var shipno = computer[y][x][1];
      if (--computersships[shipno][1] == 0)
      {
        sinkShip(computer,shipno,true);
        alert("Upotit "+shiptypes[computersships[shipno][0]][0]+"!");
        updateStatus();
        if (--computerlives == 0)
        {
          var restart = confirm("Sinä Voitit!\nHaluatko pelata uudestaan?");
          if(restart)
          {
            location.reload();
          }
          else
          {
            window.close();
          }
          playflag = false;
        }
      }
      if (playflag)
      computerMove();
    }
    else if (computer[y][x][0] == 100)
    {
      setImage(y,x,102,true);
      computerMove();
    }
  }
}

// Function to make the computers move. Note that the computer does not cheat, oh no!
function computerMove()
{
  var x,y,pass;
  var sx,sy;
  var selected = false;
  
  // Make two passes during 'shoot to kill' mode
  for (pass=0;pass<2;++pass)
  {
    for (y=0;y<gridy && !selected;++y)
    {
      for (x=0;x<gridx && !selected;++x)
      {
        // Explosion shown at this position
        if (player[y][x][0]==103)
        {
          sx=x; sy=y;
          var nup=(y>0 && player[y-1][x][0]<=100);
          var ndn=(y<gridy-1 && player[y+1][x][0]<=100);
          var nlt=(x>0 && player[y][x-1][0]<=100);
          var nrt=(x<gridx-1 && player[y][x+1][0]<=100);
          if (pass == 0)
          {
            // On first pass look for two explosions in a row - next shot will be inline
            var yup=(y>0 && player[y-1][x][0]==103);
            var ydn=(y<gridy-1 && player[y+1][x][0]==103);
            var ylt=(x>0 && player[y][x-1][0]==103);
            var yrt=(x<gridx-1 && player[y][x+1][0]==103);
            if (nlt && yrt)
            {
              sx = x-1; selected=true;
            }
            else if (nrt && ylt)
            {
              sx = x+1; selected=true;
            }
            else if (nup && ydn)
            {
              sy = y-1; selected=true;
            }
            else if (ndn && yup)
            {
              sy = y+1; selected=true;
            }
          }
          else
          {
            // Second pass look for single explosion - fire shots all around it
            if (nlt)
            {
              sx=x-1; selected=true;
            }
            else if (nrt)
            {
              sx=x+1; selected=true;
            }
            else if (nup)
            {
              sy=y-1; selected=true;
            }
            else if (ndn)
            {
              sy=y+1; selected=true;
            }
          }
        }
      }
    }
  }
  if (!selected)
  {
    /* Nothing found in 'shoot to kill' mode, so we're just taking
       potshots. Random shots are in a chequerboard pattern for
       maximum efficiency, and never twice in the same place */
    do
    {
      sy = Math.floor(Math.random() * gridy);
      sx = Math.floor(Math.random() * gridx/2)*2+sy%2;
    }
    while( player[sy][sx][0]>100 );
  }
  if (player[sy][sx][0] < 100)
  {
    // Hit something
    setImage(sy,sx,103,false);
    var shipno = player[sy][sx][1];
    if (--playersships[shipno][1] == 0)
    {
      sinkShip(player,shipno,false);
      alert("Tietokone upotti "+shiptypes[playersships[shipno][0]][0]+"!");
      if (--playerlives == 0)
      {
        knowYourEnemy();
        var restart = confirm("Tietokone voitti!\nHaluatko pelata uudestaan?");
        if(restart)
        {
          location.reload();
        }
        else
        {
          window.close();
        }
        playflag = false;
      }
    }
  }
  else
  {
    // Missed
    setImage(sy,sx,102,false);
  }
}

// When whole ship is hit, show it using changed graphics
function sinkShip(grid,shipno,ispc)
{
  var y,x;
  for (y=0;y<gridx;++y)
  {
    for (x=0;x<gridx;++x)
    {
      if (grid[y][x][1] == shipno)
      if (ispc) setImage(y,x,computer[y][x][2],true);
      else setImage(y,x,player[y][x][2],false);
    }
  }
}

// Show location of all the computers ships - when player has lost
function knowYourEnemy()
{
  var y,x;
  for (y=0;y<gridx;++y)
  {
    for (x=0;x<gridx;++x)
    {
      if (computer[y][x][0] == 103)
      setImage(y,x,computer[y][x][2],true);
      else if (computer[y][x][0] < 100)
      setImage(y,x,computer[y][x][0],true);
    }
  }
}

// Show how many ships computer has left
function updateStatus()
{
  var f=false,i,s = "Tietokone omistaa ";
  for (i=0;i<computersships.length;++i)
  {
    if (computersships[i][1] > 0)
    {
      if (f) s=s+", "; else f=true;
      s = s + shiptypes[computersships[i][0]][0];
    }
  }
  if (!f) s = s + "...ei enää mitään, kiitos sinulle!";
  statusmsg = s;
  window.status = statusmsg;
}
function setStatus()
{
  window.status = statusmsg;
}
// Start the game!
imagePreload();
player = setupPlayer(false);
computer = setupPlayer(true);
document.write("<table><tr><td class=\"center\"><strong>Tietokoneen laivasto</strong></td>"+
"<td class=\"center\"><strong>Pelaajan laivasto</strong></td></tr><tr><td>");
showGrid(true);
document.write("</td><td>");
showGrid(false);
document.write("</td></tr></table>");
updateStatus();
setInterval("setStatus();", 500);
// End