src/chess.lua

   1 local realchess = {}
   2 screwdriver = screwdriver or {}
   3
   4 local function index_to_xy(idx)
   5         idx = idx - 1
   6         local x = idx % 8
   7         local y = (idx - x) / 8
   8         return x, y
   9 end
  10
  11 local function xy_to_index(x, y)
  12         return x + y * 8 + 1
  13 end
  14
  15 local function get_square(a, b)
  16         return (a * 8) - (8 - b)
  17 end
  18
  19 local chat_prefix = minetest.colorize("#FFFF00", "[Chess] ")
  20 local letters = {'A','B','C','D','E','F','G','H'}
  21
  22 local rowDirs = {-1, -1, -1, 0, 0, 1, 1, 1}
  23 local colDirs = {-1, 0, 1, -1, 1, -1, 0, 1}
  24
  25 local bishopThreats = {true,  false, true,  false, false, true,  false, true}
  26 local rookThreats   = {false, true,  false, true,  true,  false, true,  false}
  27 local queenThreats  = {true,  true,  true,  true,  true,  true,  true,  true}
  28 local kingThreats   = {true,  true,  true,  true,  true,  true,  true,  true}
  29
  30 local function king_attack(color, idx, inv)
  31         local threatDetected = false
  32         local kill           = color == "white"
  33         local pawnThreats    = {kill, false, kill, false, false, not kill, false, not kill}
  34
  35         for dir = 1, 8 do
  36                 if not threatDetected then
  37                         local col, row = index_to_xy(idx)
  38                         col, row = col + 1, row + 1
  39
  40                         for step = 1, 8 do
  41                                 row = row + rowDirs[dir]
  42                                 col = col + colDirs[dir]
  43
  44                                 if row >= 1 and row <= 8 and col >= 1 and col <= 8 then
  45                                         local square            = get_square(row, col)
  46                                         local square_name       = inv:get_stack("board", square):get_name()
  47                                         local piece, pieceColor = square_name:match(":(%w+)_(%w+)")
  48
  49                                         if piece then
  50                                                 if pieceColor ~= color then
  51                                                         if piece == "bishop" and bishopThreats[dir] then
  52                                                                 threatDetected = true
  53                                                         elseif piece == "rook" and rookThreats[dir] then
  54                                                                 threatDetected = true
  55                                                         elseif piece == "queen" and queenThreats[dir] then
  56                                                                 threatDetected = true
  57                                                         else
  58                                                                 if step == 1 then
  59                                                                         if piece == "pawn" and pawnThreats[dir] then
  60                                                                                 threatDetected = true
  61                                                                         end
  62                                                                         if piece == "king" and kingThreats[dir] then
  63                                                                                 threatDetected = true
  64                                                                         end
  65                                                                 end
  66                                                         end
  67                                                 end
  68                                                 break
  69                                         end
  70                                 end
  71                         end
  72                 end
  73         end
  74
  75         return threatDetected
  76 end
  77
  78 local function locate_kings(inv)
  79         local Bidx, Widx
  80         for i = 1, 64 do
  81                 local piece, color = inv:get_stack("board", i):get_name():match(":(%w+)_(%w+)")
  82                 if piece == "king" then
  83                         if color == "black" then
  84                                 Bidx = i
  85                         else
  86                                 Widx = i
  87                         end
  88                 end
  89         end
  90
  91         return Bidx, Widx
  92 end
  93
  94 local pieces = {
  95         "realchess:rook_black_1",
  96         "realchess:knight_black_1",
  97         "realchess:bishop_black_1",
  98         "realchess:queen_black",
  99         "realchess:king_black",
 100         "realchess:bishop_black_2",
 101         "realchess:knight_black_2",
 102         "realchess:rook_black_2",
 103         "realchess:pawn_black_1",
 104         "realchess:pawn_black_2",
 105         "realchess:pawn_black_3",
 106         "realchess:pawn_black_4",
 107         "realchess:pawn_black_5",
 108         "realchess:pawn_black_6",
 109         "realchess:pawn_black_7",
 110         "realchess:pawn_black_8",
 111         '','','','','','','','','','','','','','','','',
 112         '','','','','','','','','','','','','','','','',
 113         "realchess:pawn_white_1",
 114         "realchess:pawn_white_2",
 115         "realchess:pawn_white_3",
 116         "realchess:pawn_white_4",
 117         "realchess:pawn_white_5",
 118         "realchess:pawn_white_6",
 119         "realchess:pawn_white_7",
 120         "realchess:pawn_white_8",
 121         "realchess:rook_white_1",
 122         "realchess:knight_white_1",
 123         "realchess:bishop_white_1",
 124         "realchess:queen_white",
 125         "realchess:king_white",
 126         "realchess:bishop_white_2",
 127         "realchess:knight_white_2",
 128         "realchess:rook_white_2"
 129 }
 130
 131 local pieces_str, x = "", 0
 132 for i = 1, #pieces do
 133         local p = pieces[i]:match(":(%w+_%w+)")
 134         if pieces[i]:find(":(%w+)_(%w+)") and not pieces_str:find(p) then
 135                 pieces_str = pieces_str .. x .. "=" .. p .. ".png,"
 136                 x = x + 1
 137         end
 138 end
 139 pieces_str = pieces_str .. "69=mailbox_blank16.png"
 140
 141 local fs = [[
 142         size[14.7,10;]
 143         no_prepend[]
 144         bgcolor[#080808BB;true]
 145         background[0,0;14.7,10;chess_bg.png]
 146         list[context;board;0.3,1;8,8;]
 147         listcolors[#00000000;#00000000;#00000000;#30434C;#FFF]
 148         tableoptions[background=#00000000;highlight=#00000000;border=false]
 149         button[10.5,8.5;2,2;new;New game]
 150 ]] ..  "tablecolumns[image," .. pieces_str ..
 151                 ";text;color;text;color;text;image," .. pieces_str .. "]"
 152
 153 local function get_moves_list(meta, pieceFrom, pieceTo, pieceTo_s, from_x, to_x, from_y, to_y)
 154         local moves           = meta:get_string("moves")
 155         local pieceFrom_s     = pieceFrom:match(":(%w+_%w+)")
 156         local pieceFrom_si_id = pieces_str:match("(%d+)=" .. pieceFrom_s)
 157         local pieceTo_si_id   = pieceTo_s ~= "" and pieces_str:match("(%d+)=" .. pieceTo_s) or ""
 158
 159         local coordFrom = letters[from_x + 1] .. math.abs(from_y - 8)
 160         local coordTo   = letters[to_x   + 1] .. math.abs(to_y   - 8)
 161
 162         local new_moves = pieceFrom_si_id .. "," ..
 163                 coordFrom .. "," ..
 164                         (pieceTo ~= "" and "#33FF33" or "#FFFFFF") .. ", > ,#FFFFFF," ..
 165                 coordTo .. "," ..
 166                 (pieceTo ~= "" and pieceTo_si_id or "69") .. "," ..
 167                 moves
 168
 169         meta:set_string("moves", new_moves)
 170 end
 171
 172 local function get_eaten_list(meta, pieceTo, pieceTo_s)
 173         local eaten = meta:get_string("eaten")
 174         if pieceTo ~= "" then
 175                 eaten = eaten .. pieceTo_s .. ","
 176         end
 177
 178         meta:set_string("eaten", eaten)
 179
 180         local eaten_t   = string.split(eaten, ",")
 181         local eaten_img = ""
 182
 183         local a, b = 0, 0
 184         for i = 1, #eaten_t do
 185                 local is_white = eaten_t[i]:sub(-5,-1) == "white"
 186                 local X = (is_white and a or b) % 4
 187                 local Y = ((is_white and a or b) % 16 - X) / 4
 188
 189                 if is_white then
 190                         a = a + 1
 191                 else
 192                         b = b + 1
 193                 end
 194
 195                 eaten_img = eaten_img ..
 196                         "image[" .. ((X + (is_white and 11.7 or 8.8)) - (X * 0.45)) .. "," ..
 197                                     ((Y + 5.56) - (Y * 0.2)) .. ";1,1;" .. eaten_t[i] .. ".png]"
 198         end
 199
 200         meta:set_string("eaten_img", eaten_img)
 201 end
 202
 203 function realchess.init(pos)
 204         local meta = minetest.get_meta(pos)
 205         local inv  = meta:get_inventory()
 206
 207         meta:set_string("formspec", fs)
 208         meta:set_string("infotext", "Chess Board")
 209         meta:set_string("playerBlack", "")
 210         meta:set_string("playerWhite", "")
 211         meta:set_string("lastMove",    "")
 212
 213         meta:set_int("lastMoveTime",   0)
 214         meta:set_int("castlingBlackL", 1)
 215         meta:set_int("castlingBlackR", 1)
 216         meta:set_int("castlingWhiteL", 1)
 217         meta:set_int("castlingWhiteR", 1)
 218
 219         meta:set_string("moves", "")
 220         meta:set_string("eaten", "")
 221
 222         inv:set_list("board", pieces)
 223         inv:set_size("board", 64)
 224 end
 225
 226 function realchess.move(pos, from_list, from_index, to_list, to_index, _, player)
 227         if from_list ~= "board" and to_list ~= "board" then
 228                 return 0
 229         end
 230
 231         local meta        = minetest.get_meta(pos)
 232         local playerName  = player:get_player_name()
 233         local inv         = meta:get_inventory()
 234         local pieceFrom   = inv:get_stack(from_list, from_index):get_name()
 235         local pieceTo     = inv:get_stack(to_list, to_index):get_name()
 236         local lastMove    = meta:get_string("lastMove")
 237         local playerWhite = meta:get_string("playerWhite")
 238         local playerBlack = meta:get_string("playerBlack")
 239         local thisMove    -- Will replace lastMove when move is legal
 240
 241         if pieceFrom:find("white") then
 242                 if playerWhite ~= "" and playerWhite ~= playerName then
 243                         minetest.chat_send_player(playerName, chat_prefix .. "Someone else plays white pieces!")
 244                         return 0
 245                 end
 246
 247                 if lastMove ~= "" and lastMove ~= "black" then
 248                         return 0
 249                 end
 250
 251                 if pieceTo:find("white") then
 252                         -- Don't replace pieces of same color
 253                         return 0
 254                 end
 255
 256                 playerWhite = playerName
 257                 thisMove = "white"
 258
 259         elseif pieceFrom:find("black") then
 260                 if playerBlack ~= "" and playerBlack ~= playerName then
 261                         minetest.chat_send_player(playerName, chat_prefix .. "Someone else plays black pieces!")
 262                         return 0
 263                 end
 264
 265                 if lastMove ~= "" and lastMove ~= "white" then
 266                         return 0
 267                 end
 268
 269                 if pieceTo:find("black") then
 270                         -- Don't replace pieces of same color
 271                         return 0
 272                 end
 273
 274                 playerBlack = playerName
 275                 thisMove = "black"
 276         end
 277
 278         -- MOVE LOGIC
 279
 280         local from_x, from_y = index_to_xy(from_index)
 281         local to_x, to_y     = index_to_xy(to_index)
 282
 283         -- PAWN
 284         if pieceFrom:sub(11,14) == "pawn" then
 285                 if thisMove == "white" then
 286                         local pawnWhiteMove = inv:get_stack(from_list, xy_to_index(from_x, from_y - 1)):get_name()
 287                         -- white pawns can go up only
 288                         if from_y - 1 == to_y then
 289                                 if from_x == to_x then
 290                                         if pieceTo ~= "" then
 291                                                 return 0
 292                                         elseif to_index >= 1 and to_index <= 8 then
 293                                                 inv:set_stack(from_list, from_index, "realchess:queen_white")
 294                                         end
 295                                 elseif from_x - 1 == to_x or from_x + 1 == to_x then
 296                                         if not pieceTo:find("black") then
 297                                                 return 0
 298                                         elseif to_index >= 1 and to_index <= 8 then
 299                                                 inv:set_stack(from_list, from_index, "realchess:queen_white")
 300                                         end
 301                                 else
 302                                         return 0
 303                                 end
 304                         elseif from_y - 2 == to_y then
 305                                 if pieceTo ~= "" or from_y < 6 or pawnWhiteMove ~= "" then
 306                                         return 0
 307                                 end
 308                         else
 309                                 return 0
 310                         end
 311
 312                         --[[
 313                              if x not changed
 314                                   ensure that destination cell is empty
 315                              elseif x changed one unit left or right
 316                                   ensure the pawn is killing opponent piece
 317                              else
 318                                   move is not legal - abort
 319                         ]]
 320
 321                         if from_x == to_x then
 322                                 if pieceTo ~= "" then
 323                                         return 0
 324                                 end
 325                         elseif from_x - 1 == to_x or from_x + 1 == to_x then
 326                                 if not pieceTo:find("black") then
 327                                         return 0
 328                                 end
 329                         else
 330                                 return 0
 331                         end
 332
 333                 elseif thisMove == "black" then
 334                         local pawnBlackMove = inv:get_stack(from_list, xy_to_index(from_x, from_y + 1)):get_name()
 335                         -- black pawns can go down only
 336                         if from_y + 1 == to_y then
 337                                 if from_x == to_x then
 338                                         if pieceTo ~= "" then
 339                                                 return 0
 340                                         elseif to_index >= 57 and to_index <= 64 then
 341                                                 inv:set_stack(from_list, from_index, "realchess:queen_black")
 342                                         end
 343                                 elseif from_x - 1 == to_x or from_x + 1 == to_x then
 344                                         if not pieceTo:find("white") then
 345                                                 return 0
 346                                         elseif to_index >= 57 and to_index <= 64 then
 347                                                 inv:set_stack(from_list, from_index, "realchess:queen_black")
 348                                         end
 349                                 else
 350                                         return 0
 351                                 end
 352                         elseif from_y + 2 == to_y then
 353                                 if pieceTo ~= "" or from_y > 1 or pawnBlackMove ~= "" then
 354                                         return 0
 355                                 end
 356                         else
 357                                 return 0
 358                         end
 359
 360                         --[[
 361                              if x not changed
 362                                   ensure that destination cell is empty
 363                              elseif x changed one unit left or right
 364                                   ensure the pawn is killing opponent piece
 365                              else
 366                                   move is not legal - abort
 367                         ]]
 368
 369                         if from_x == to_x then
 370                                 if pieceTo ~= "" then
 371                                         return 0
 372                                 end
 373                         elseif from_x - 1 == to_x or from_x + 1 == to_x then
 374                                 if not pieceTo:find("white") then
 375                                         return 0
 376                                 end
 377                         else
 378                                 return 0
 379                         end
 380                 else
 381                         return 0
 382                 end
 383
 384         -- ROOK
 385         elseif pieceFrom:sub(11,14) == "rook" then
 386                 if from_x == to_x then
 387                         -- Moving vertically
 388                         if from_y < to_y then
 389                                 -- Moving down
 390                                 -- Ensure that no piece disturbs the way
 391                                 for i = from_y + 1, to_y - 1 do
 392                                         if inv:get_stack(from_list, xy_to_index(from_x, i)):get_name() ~= "" then
 393                                                 return 0
 394                                         end
 395                                 end
 396                         else
 397                                 -- Mocing up
 398                                 -- Ensure that no piece disturbs the way
 399                                 for i = to_y + 1, from_y - 1 do
 400                                         if inv:get_stack(from_list, xy_to_index(from_x, i)):get_name() ~= "" then
 401                                                 return 0
 402                                         end
 403                                 end
 404                         end
 405                 elseif from_y == to_y then
 406                         -- Mocing horizontally
 407                         if from_x < to_x then
 408                                 -- mocing right
 409                                 -- ensure that no piece disturbs the way
 410                                 for i = from_x + 1, to_x - 1 do
 411                                         if inv:get_stack(from_list, xy_to_index(i, from_y)):get_name() ~= "" then
 412                                                 return 0
 413                                         end
 414                                 end
 415                         else
 416                                 -- Mocing left
 417                                 -- Ensure that no piece disturbs the way
 418                                 for i = to_x + 1, from_x - 1 do
 419                                         if inv:get_stack(from_list, xy_to_index(i, from_y)):get_name() ~= "" then
 420                                                 return 0
 421                                         end
 422                                 end
 423                         end
 424                 else
 425                         -- Attempt to move arbitrarily -> abort
 426                         return 0
 427                 end
 428
 429                 if thisMove == "white" or thisMove == "black" then
 430                         if pieceFrom:sub(-1) == "1" then
 431                                 meta:set_int("castlingWhiteL", 0)
 432                         elseif pieceFrom:sub(-1) == "2" then
 433                                 meta:set_int("castlingWhiteR", 0)
 434                         end
 435                 end
 436
 437         -- KNIGHT
 438         elseif pieceFrom:sub(11,16) == "knight" then
 439                 -- Get relative pos
 440                 local dx = from_x - to_x
 441                 local dy = from_y - to_y
 442
 443                 -- Get absolute values
 444                 if dx < 0 then dx = -dx end
 445                 if dy < 0 then dy = -dy end
 446
 447                 -- Sort x and y
 448                 if dx > dy then dx, dy = dy, dx end
 449
 450                 -- Ensure that dx == 1 and dy == 2
 451                 if dx ~= 1 or dy ~= 2 then
 452                         return 0
 453                 end
 454                 -- Just ensure that destination cell does not contain friend piece
 455                 -- ^ It was done already thus everything ok
 456
 457         -- BISHOP
 458         elseif pieceFrom:sub(11,16) == "bishop" then
 459                 -- Get relative pos
 460                 local dx = from_x - to_x
 461                 local dy = from_y - to_y
 462
 463                 -- Get absolute values
 464                 if dx < 0 then dx = -dx end
 465                 if dy < 0 then dy = -dy end
 466
 467                 -- Ensure dx and dy are equal
 468                 if dx ~= dy then return 0 end
 469
 470                 if from_x < to_x then
 471                         if from_y < to_y then
 472                                 -- Moving right-down
 473                                 -- Ensure that no piece disturbs the way
 474                                 for i = 1, dx - 1 do
 475                                         if inv:get_stack(from_list, xy_to_index(from_x + i, from_y + i)):get_name() ~= "" then
 476                                                 return 0
 477                                         end
 478                                 end
 479                         else
 480                                 -- Moving right-up
 481                                 -- Ensure that no piece disturbs the way
 482                                 for i = 1, dx - 1 do
 483                                         if inv:get_stack(from_list, xy_to_index(from_x + i, from_y - i)):get_name() ~= "" then
 484                                                 return 0
 485                                         end
 486                                 end
 487                         end
 488                 else
 489                         if from_y < to_y then
 490                                 -- Moving left-down
 491                                 -- Ensure that no piece disturbs the way
 492                                 for i = 1, dx - 1 do
 493                                         if inv:get_stack(from_list, xy_to_index(from_x - i, from_y + i)):get_name() ~= "" then
 494                                                 return 0
 495                                         end
 496                                 end
 497                         else
 498                                 -- Moving left-up
 499                                 -- ensure that no piece disturbs the way
 500                                 for i = 1, dx - 1 do
 501                                         if inv:get_stack(from_list, xy_to_index(from_x - i, from_y - i)):get_name() ~= "" then
 502                                                 return 0
 503                                         end
 504                                 end
 505                         end
 506                 end
 507
 508         -- QUEEN
 509         elseif pieceFrom:sub(11,15) == "queen" then
 510                 local dx = from_x - to_x
 511                 local dy = from_y - to_y
 512
 513                 -- Get absolute values
 514                 if dx < 0 then dx = -dx end
 515                 if dy < 0 then dy = -dy end
 516
 517                 -- Ensure valid relative move
 518                 if dx ~= 0 and dy ~= 0 and dx ~= dy then
 519                         return 0
 520                 end
 521
 522                 if from_x == to_x then
 523                         if from_y < to_y then
 524                                 -- Goes down
 525                                 -- Ensure that no piece disturbs the way
 526                                 for i = 1, dx - 1 do
 527                                         if inv:get_stack(from_list, xy_to_index(from_x, from_y + i)):get_name() ~= "" then
 528                                                 return 0
 529                                         end
 530                                 end
 531                         else
 532                                 -- Goes up
 533                                 -- Ensure that no piece disturbs the way
 534                                 for i = 1, dx - 1 do
 535                                         if inv:get_stack(from_list, xy_to_index(from_x, from_y - i)):get_name() ~= "" then
 536                                                 return 0
 537                                         end
 538                                 end
 539                         end
 540                 elseif from_x < to_x then
 541                         if from_y == to_y then
 542                                 -- Goes right
 543                                 -- Ensure that no piece disturbs the way
 544                                 for i = 1, dx - 1 do
 545                                         if inv:get_stack(from_list, xy_to_index(from_x + i, from_y)):get_name() ~= "" then
 546                                                 return 0
 547                                         end
 548                                 end
 549                         elseif from_y < to_y then
 550                                 -- Goes right-down
 551                                 -- Ensure that no piece disturbs the way
 552                                 for i = 1, dx - 1 do
 553                                         if inv:get_stack(from_list, xy_to_index(from_x + i, from_y + i)):get_name() ~= "" then
 554                                                 return 0
 555                                         end
 556                                 end
 557                         else
 558                                 -- Goes right-up
 559                                 -- Ensure that no piece disturbs the way
 560                                 for i = 1, dx - 1 do
 561                                         if inv:get_stack(from_list, xy_to_index(from_x + i, from_y - i)):get_name() ~= "" then
 562                                                 return 0
 563                                         end
 564                                 end
 565                         end
 566                 else
 567                         if from_y == to_y then
 568                                 -- Goes left
 569                                 -- Ensure that no piece disturbs the way and destination cell does
 570                                 for i = 1, dx - 1 do
 571                                         if inv:get_stack(from_list, xy_to_index(from_x - i, from_y)):get_name() ~= "" then
 572                                                 return 0
 573                                         end
 574                                 end
 575                         elseif from_y < to_y then
 576                                 -- Goes left-down
 577                                 -- Ensure that no piece disturbs the way
 578                                 for i = 1, dx - 1 do
 579                                         if inv:get_stack(from_list, xy_to_index(from_x - i, from_y + i)):get_name() ~= "" then
 580                                                 return 0
 581                                         end
 582                                 end
 583                         else
 584                                 -- Goes left-up
 585                                 -- Ensure that no piece disturbs the way
 586                                 for i = 1, dx - 1 do
 587                                         if inv:get_stack(from_list, xy_to_index(from_x - i, from_y - i)):get_name() ~= "" then
 588                                                 return 0
 589                                         end
 590                                 end
 591                         end
 592                 end
 593
 594         -- KING
 595         elseif pieceFrom:sub(11,14) == "king" then
 596                 local dx = from_x - to_x
 597                 local dy = from_y - to_y
 598                 local check = true
 599
 600                 if thisMove == "white" then
 601                         if from_y == 7 and to_y == 7 then
 602                                 if to_x == 1 then
 603                                         local castlingWhiteL = meta:get_int("castlingWhiteL")
 604                                         local idx57 = inv:get_stack(from_list, 57):get_name()
 605
 606                                         if castlingWhiteL == 1 and idx57 == "realchess:rook_white_1" then
 607                                                 for i = 58, from_index - 1 do
 608                                                         if inv:get_stack(from_list, i):get_name() ~= "" then
 609                                                                 return 0
 610                                                         end
 611                                                 end
 612                                                 inv:set_stack(from_list, 57, "")
 613                                                 inv:set_stack(from_list, 59, "realchess:rook_white_1")
 614                                                 check = false
 615                                         end
 616                                 elseif to_x == 6 then
 617                                         local castlingWhiteR = meta:get_int("castlingWhiteR")
 618                                         local idx64 = inv:get_stack(from_list, 64):get_name()
 619
 620                                         if castlingWhiteR == 1 and idx64 == "realchess:rook_white_2" then
 621                                                 for i = from_index + 1, 63 do
 622                                                         if inv:get_stack(from_list, i):get_name() ~= "" then
 623                                                                 return 0
 624                                                         end
 625                                                 end
 626                                                 inv:set_stack(from_list, 62, "realchess:rook_white_2")
 627                                                 inv:set_stack(from_list, 64, "")
 628                                                 check = false
 629                                         end
 630                                 end
 631                         end
 632                 elseif thisMove == "black" then
 633                         if from_y == 0 and to_y == 0 then
 634                                 if to_x == 1 then
 635                                         local castlingBlackL = meta:get_int("castlingBlackL")
 636                                         local idx1 = inv:get_stack(from_list, 1):get_name()
 637
 638                                         if castlingBlackL == 1 and idx1 == "realchess:rook_black_1" then
 639                                                 for i = 2, from_index - 1 do
 640                                                         if inv:get_stack(from_list, i):get_name() ~= "" then
 641                                                                 return 0
 642                                                         end
 643                                                 end
 644
 645                                                 inv:set_stack(from_list, 1, "")
 646                                                 inv:set_stack(from_list, 3, "realchess:rook_black_1")
 647                                                 check = false
 648                                         end
 649                                 elseif to_x == 6 then
 650                                         local castlingBlackR = meta:get_int("castlingBlackR")
 651                                         local idx8 = inv:get_stack(from_list, 1):get_name()
 652
 653                                         if castlingBlackR == 1 and idx8 == "realchess:rook_black_2" then
 654                                                 for i = from_index + 1, 7 do
 655                                                         if inv:get_stack(from_list, i):get_name() ~= "" then
 656                                                                 return 0
 657                                                         end
 658                                                 end
 659
 660                                                 inv:set_stack(from_list, 6, "realchess:rook_black_2")
 661                                                 inv:set_stack(from_list, 8, "")
 662                                                 check = false
 663                                         end
 664                                 end
 665                         end
 666                 end
 667
 668                 if check then
 669                         if dx < 0 then
 670                                 dx = -dx
 671                         end
 672
 673                         if dy < 0 then
 674                                 dy = -dy
 675                         end
 676
 677                         if dx > 1 or dy > 1 then
 678                                 return 0
 679                         end
 680                 end
 681
 682                 if thisMove == "white" then
 683                         meta:set_int("castlingWhiteL", 0)
 684                         meta:set_int("castlingWhiteR", 0)
 685
 686                         local whiteAttacked = king_attack("white", to_index, inv)
 687                         if whiteAttacked then
 688                                 return 0
 689                         end
 690
 691                 elseif thisMove == "black" then
 692                         meta:set_int("castlingBlackL", 0)
 693                         meta:set_int("castlingBlackR", 0)
 694
 695                         local blackAttacked = king_attack("black", to_index, inv)
 696                         if blackAttacked then
 697                                 return 0
 698                         end
 699                 end
 700         end
 701
 702         lastMove = thisMove
 703
 704         meta:set_string("lastMove", lastMove)
 705         meta:set_int("lastMoveTime", minetest.get_gametime())
 706         meta:set_string("playerWhite", playerWhite)
 707         meta:set_string("playerBlack", playerBlack)
 708
 709         local pieceTo_s = pieceTo ~= "" and pieceTo:match(":(%w+_%w+)") or ""
 710         get_moves_list(meta, pieceFrom, pieceTo, pieceTo_s, from_x, to_x, from_y, to_y)
 711         get_eaten_list(meta, pieceTo, pieceTo_s)
 712
 713         return 1
 714 end
 715
 716 local function timeout_format(timeout_limit)
 717         local time_remaining = timeout_limit - minetest.get_gametime()
 718         local minutes        = math.floor(time_remaining / 60)
 719         local seconds        = time_remaining % 60
 720
 721         if minutes == 0 then
 722                 return seconds .. " sec."
 723         end
 724
 725         return minutes .. " min. " .. seconds .. " sec."
 726 end
 727
 728 function realchess.fields(pos, _, fields, sender)
 729         local playerName    = sender:get_player_name()
 730         local meta          = minetest.get_meta(pos)
 731         local timeout_limit = meta:get_int("lastMoveTime") + 300
 732         local playerWhite   = meta:get_string("playerWhite")
 733         local playerBlack   = meta:get_string("playerBlack")
 734         local lastMoveTime  = meta:get_int("lastMoveTime")
 735         if fields.quit then return end
 736
 737         -- Timeout is 5 min. by default for resetting the game (non-players only)
 738         if fields.new then
 739                 if (playerWhite == playerName or playerBlack == playerName) then
 740                         realchess.init(pos)
 741
 742                 elseif lastMoveTime ~= 0 then
 743                         if minetest.get_gametime() >= timeout_limit and
 744                                         (playerWhite ~= playerName or playerBlack ~= playerName) then
 745                                 realchess.init(pos)
 746                         else
 747                                 minetest.chat_send_player(playerName, chat_prefix ..
 748                                         "You can't reset the chessboard, a game has been started. " ..
 749                                         "If you aren't a current player, try again in " ..
 750                                         timeout_format(timeout_limit))
 751                         end
 752                 end
 753         end
 754 end
 755
 756 function realchess.dig(pos, player)
 757         if not player then
 758                 return false
 759         end
 760
 761         local meta          = minetest.get_meta(pos)
 762         local playerName    = player:get_player_name()
 763         local timeout_limit = meta:get_int("lastMoveTime") + 300
 764         local lastMoveTime  = meta:get_int("lastMoveTime")
 765
 766         -- Timeout is 5 min. by default for digging the chessboard (non-players only)
 767         return (lastMoveTime == 0 and minetest.get_gametime() > timeout_limit) or
 768                 minetest.chat_send_player(playerName, chat_prefix ..
 769                                 "You can't dig the chessboard, a game has been started. " ..
 770                                 "Reset it first if you're a current player, or dig it again in " ..
 771                                 timeout_format(timeout_limit))
 772 end
 773
 774 function realchess.on_move(pos, from_list, from_index)
 775         local meta = minetest.get_meta(pos)
 776         local inv  = minetest.get_meta(pos):get_inventory()
 777         inv:set_stack(from_list, from_index, '')
 778
 779         local black_king_idx, white_king_idx = locate_kings(inv)
 780         local black_king_attacked = king_attack("black", black_king_idx, inv)
 781         local white_king_attacked = king_attack("white", white_king_idx, inv)
 782
 783         local playerWhite = meta:get_string("playerWhite")
 784         local playerBlack = meta:get_string("playerBlack")
 785
 786         local moves       = meta:get_string("moves")
 787         local eaten_img   = meta:get_string("eaten_img")
 788         local lastMove    = meta:get_string("lastMove")
 789         local turnBlack   = minetest.colorize("#000001", (lastMove == "white" and playerBlack ~= "") and
 790                             playerBlack .. "..." or playerBlack)
 791         local turnWhite   = minetest.colorize("#000001", (lastMove == "black" and playerWhite ~= "") and
 792                             playerWhite .. "..." or playerWhite)
 793         local check_s     = minetest.colorize("#FF0000", "\\[check\\]")
 794
 795         local formspec = fs ..
 796                 "label[1.9,0.3;"  .. turnBlack .. (black_king_attacked and " " .. check_s or "") .. "]" ..
 797                 "label[1.9,9.15;" .. turnWhite .. (white_king_attacked and " " .. check_s or "") .. "]" ..
 798                 "table[8.9,1.05;5.07,3.75;moves;" .. moves:sub(1,-2) .. ";1]" ..
 799                 eaten_img
 800
 801         meta:set_string("formspec", formspec)
 802
 803         return false
 804 end
 805
 806 minetest.register_node(":realchess:chessboard", {
 807         description = "Chess Board",
 808         drawtype = "nodebox",
 809         paramtype = "light",
 810         paramtype2 = "facedir",
 811         inventory_image = "chessboard_top.png",
 812         wield_image = "chessboard_top.png",
 813         tiles = {"chessboard_top.png", "chessboard_top.png", "chessboard_sides.png"},
 814         groups = {choppy=3, oddly_breakable_by_hand=2, flammable=3},
 815         sounds = default.node_sound_wood_defaults(),
 816         node_box = {type = "fixed", fixed = {-.375, -.5, -.375, .375, -.4375, .375}},
 817         sunlight_propagates = true,
 818         on_rotate = screwdriver.rotate_simple,
 819         can_dig = realchess.dig,
 820         on_construct = realchess.init,
 821         on_receive_fields = realchess.fields,
 822         allow_metadata_inventory_move = realchess.move,
 823         on_metadata_inventory_move = realchess.on_move,
 824         allow_metadata_inventory_take = function() return 0 end
 825 })
 826
 827 local function register_piece(name, count)
 828         for _, color in pairs({"black", "white"}) do
 829         if not count then
 830                 minetest.register_craftitem(":realchess:" .. name .. "_" .. color, {
 831                         description = color:gsub("^%l", string.upper) .. " " .. name:gsub("^%l", string.upper),
 832                         inventory_image = name .. "_" .. color .. ".png",
 833                         stack_max = 1,
 834                         groups = {not_in_creative_inventory=1}
 835                 })
 836         else
 837                 for i = 1, count do
 838                         minetest.register_craftitem(":realchess:" .. name .. "_" .. color .. "_" .. i, {
 839                                 description = color:gsub("^%l", string.upper) .. " " .. name:gsub("^%l", string.upper),
 840                                 inventory_image = name .. "_" .. color .. ".png",
 841                                 stack_max = 1,
 842                                 groups = {not_in_creative_inventory=1}
 843                         })
 844                 end
 845         end
 846         end
 847 end
 848
 849 register_piece("pawn", 8)
 850 register_piece("rook", 2)
 851 register_piece("knight", 2)
 852 register_piece("bishop", 2)
 853 register_piece("queen")
 854 register_piece("king")
 855
 856 -- Recipes
 857
 858 minetest.register_craft({
 859         output = "realchess:chessboard",
 860         recipe = {
 861                 {"dye:black", "dye:white", "dye:black"},
 862                 {"stairs:slab_wood", "stairs:slab_wood", "stairs:slab_wood"}
 863         }
 864 })