function main_control()
{
// These globals are used in the HTML template
global $current_player, $history;
global $heading, $name_white, $name_black;
global $show_command_form, $flip_board;
global $preset_from_value, $preset_to_value, $id_focus;
global $chess_board_markup, $history_markup, $promotion_dialog_markup;
global $board_encoded, $game_title, $turn_nr;
global $history_next, $history_prev;
global $href_this, $href_player, $href_flip;
global $game_state_link, $hmw_home_link;
// Initialize a bit
$promotion_popup = false;
//...NYI Show pawn promotion dialog
$show_command_form = true;
// Show the move input dialog
$game_status = IN_PROGRESS;
// The game has not ended yet
$heading = '';
// "White's move" caption
$game_title = '';
// Current game info for page title
$game_state_link = '';
// "Send this link"-link ..
$hmw_home_link = '';
// .. corrected for my stupid router
//... Remember an initial double move of a pawn
$get_en_passant = get_parameter(GET_EN_PASSANT);
$new_en_passant = '';
// Retreive GET data
$flip_board = isset($_GET[GET_FLIP_BOARD]);
$history = get_parameter(GET_HISTORY);
$goto = get_parameter(GET_GOTO);
$name_white = get_parameter(GET_WHITE, DEFAULT_NAME_WHITE);
$name_black = get_parameter(GET_BLACK, DEFAULT_NAME_BLACK);
if (get_parameter(GET_PLAYER, GET_WHITE) != GET_WHITE) {
// &player set, but not to "white", is taken as "black"
$current_player = BLACKS_MOVE;
} else {
$current_player = WHITES_MOVE;
}
// Load base positions of pieces
$base_array = decode_board(get_parameter(GET_BASE_BOARD, INITIAL_BOARD_CODED));
// Trace history (Reconstruct the current board from initial positions)
//...list( $board_array, $tie_info ) = decode_history(
$board_array = decode_history($base_array, $history, $goto);
// Execute given command
// Retreive FORM input
// Move: "from" and "to" must be field names
// Edit: "from" must be the code character for a piece and "to" a field
$clickable = $selected = array();
$redirect_after_move = false;
$cmd_piece = get_parameter(GET_FROM);
$cmd_from = strtoupper(get_parameter(GET_FROM));
// Retreive commands
$cmd_to = strtoupper(get_parameter(GET_TO));
if ($cmd_from == $cmd_to) {
// Deselect a piece
$cmd_from = $cmd_to = '';
}
if ($cmd_from == '') {
$cmd_to = '';
}
// Never allow only TO command
// Exec: Editor
if (strlen($cmd_from) == 1 && valid_field_name($cmd_to)) {
if (strpos(WHITE_PIECES . BLACK_PIECES, $cmd_from) !== false) {
list($row, $col) = field_to_rowcol($cmd_to);
if ($base_array[$row][$col] == $cmd_piece) {
// Delete existing piece
$base_array[$row][$col] = '';
} else {
if ($base_array[$row][$col] == '') {
// Add new piece
$base_array[$row][$col] = $cmd_piece;
}
}
#$base_array = $board_array;
$redirect_after_move = true;
}
// No other commands with FROM being only one char.
$cmd_from = $cmd_to = '';
}
// Make sure, no invalid data is being processed as a move
if (!valid_field_name($cmd_from)) {
$cmd_from = '';
}
if (!valid_field_name($cmd_to)) {
$cmd_to = '';
}
// Exec: Move
if ($cmd_from != '' && $cmd_to != '') {
$turn_nr = i_to_round($history);
if ($turn_nr - floor($turn_nr) == 0.5) {
$turn_nr = floor($turn_nr);
$color = 'Black';
} else {
$color = 'White';
}
debug_out($_SERVER['REMOTE_ADDR'] . " - {$name_white} vs. {$name_black}, {$turn_nr}, {$color}: {$cmd_from} - {$cmd_to}\n");
list($f_row, $f_col) = field_to_rowcol($cmd_from);
list($t_row, $t_col) = field_to_rowcol($cmd_to);
list($clickable, $selected) = select_piece($board_array, $current_player, $cmd_from, $get_en_passant);
// Check if it is our//... piece (or a piece at all)
if (!in_array($cmd_from, $clickable)) {
die("Error: clickable[{$f_row}][{$f_col}] empty.");
}
if (!in_array($cmd_to, $clickable)) {
// Capturing a piece!
echo "Capture! clickable = ";
print_r($clickable);
die;
}
// En passant
$piece = $board_array[$f_row][$f_col];
if ($piece == 'P' && $f_row == 1 || $piece == 'p' && $f_row == 6) {
if ($t_row == 3 || $t_row == 4) {
$get_en_passant = chr(ord('A') + $f_col);
}
}
if ($piece == 'P' && $t_row - $f_row == +1 || $piece == 'p' && $t_row - $f_row == -1 || $piece != 'P' && $piece != 'p') {
$get_en_passant = '';
}
// Promotion
if ($piece == 'P' && $t_row == 7 || $piece == 'p' && $t_row == 0) {
$href_this = update_href($href_this, GET_PROMOTE, chr(ord('A') + $t_col));
$promotion_popup = true;
$heading = 'Promote your pawn to:';
$board_array = apply_move($board_array, $f_row, $f_col, $t_row, $t_col);
}
// New move applied, prepare for fresh move
$clickable = $selected = array();
$cmd_from = $cmd_to = '';
// Fall through to NO COMMAND mode
$current_player = !$current_player;
$history .= encode_move($f_row, $f_col, $t_row, $t_col);
// We changed the board, but the user's browser still shows the
// move command in its address bar. An HTTP redirect is used to
// update that address, but the URL is not determined yet
if (!$promotion_popup) {
$redirect_after_move = true;
}
}
// Exec: Deselect, continuation of fall throughs above
if ($cmd_from == '' && $cmd_to == '') {
$clickable = find_movable_pieces($board_array, $current_player);
// Get rid of moves with king in check afterwards
$new = array();
foreach ($clickable as $from_field) {
// Get two arrays (clickable, selected)
$temp = select_piece($board_array, $current_player, $from_field);
// Ignore moves with only one "deselection entry"
if (count($temp[0]) > 1) {
$new[] = $from_field;
}
}
$clickable = $new;
if (count($clickable) == 0) {
if (king_in_check($board_array, $current_player)) {
$heading = HEADING_CHECK_MATE;
$game_status = $current_player != WHITES_MOVE ? WHITE_WINS : BLACK_WINS;
} else {
$heading = HEADING_STALE_MATE;
$game_status = NOONE_WINS;
}
}
}
// Exec: Select piece
if ($cmd_from != '' && $cmd_to == '' && $goto == '') {
list($clickable, $selected) = select_piece($board_array, $current_player, $cmd_from);
$heading = 'Select target';
}
// Prepare move command form
$preset_from_value = $cmd_from;
$preset_to_value = $cmd_to;
$id_focus = $preset_from_value == '' ? 'idFrom' : 'idTo';
// Generate links for main menu and board markup (pieces)
$board_encoded = encode_board($base_array);
// Name parameter as code for who's player's term this is
$p = $current_player == WHITES_MOVE ? GET_WHITE : GET_BLACK;
$href_this = update_href();
// get base link
$href_this = update_href($href_this, GET_FROM, $preset_from_value);
$href_this = update_href($href_this, GET_TO, $preset_to_value);
$href_this = update_href($href_this, GET_PLAYER, $p);
$href_this = update_href($href_this, GET_HISTORY, $history);
$href_this = update_href($href_this, GET_WHITE, $name_white);
$href_this = update_href($href_this, GET_BLACK, $name_black);
$href_this = update_href($href_this, GET_EN_PASSANT, $get_en_passant);
$href_this = update_href($href_this, GET_BASE_BOARD, $board_encoded);
if ($flip_board) {
$href_this = update_href($href_this, GET_FLIP_BOARD, '');
$href_flip = update_href($href_this, GET_FLIP_BOARD, REMOVE_FROM_LINK);
} else {
$href_flip = update_href($href_this, GET_FLIP_BOARD, '');
}
if ($current_player == BLACKS_MOVE) {
$href_player = update_href($href_this, GET_PLAYER, GET_WHITE);
} else {
$href_player = update_href($href_this, GET_PLAYER, GET_BLACK);
}
// HTTP redirect?
if (!false && $redirect_after_move) {
if (DEBUG) {
#die( "Continue: <a href='$href_this'>$href_this</a>" );
}
// Game state has been updated. In case of an executed move,
// the browser needs to reload the page with the updated URL:
header('HTTP/1.0 303 Found');
header('Location: ' . htmlspecialchars_decode($href_this));
die;
}
// Create HTML markup
// History
$history_markup = history_markup($base_array, $history, $href_this, $name_white, $name_black, $game_status);
// Promotion
if ($promotion_popup) {
$promotion_dialog_markup = promotion_dialog_markup($href_this, $current_player, $t_row, $t_col, $history);
$clickable = $selected = array();
} else {
$promotion_dialog_markup = '';
}
// Board
if (STEADY_BOARD && $current_player == BLACKS_MOVE) {
//... GET switch
$flip_board = !$flip_board;
}
if (isset($_GET[GET_GOTO])) {
$clickable = $selected = array();
} else {
if ($history > '' && $cmd_from == $cmd_to) {
if (substr($history, -4, 1) == '(') {
// Skip promotion
$selected[] = decode_field(substr($history, -3, 1));
$selected[] = decode_field(substr($history, -6, 1));
} else {
// Normal move
$selected[] = decode_field(substr($history, -2, 1));
$selected[] = decode_field(substr($history, -1, 1));
}
}
}
$chess_board_markup = chess_board_markup($href_this, $board_array, $clickable, $selected, $current_player, $flip_board);
// If no heading was set above, say who's next
if ($goto != '') {
$current_player = $goto % 2 != 0;
}
if ($heading == '') {
$heading = $current_player ? $name_white : $name_black;
$heading = ucfirst($heading) . "'";
if (substr($heading, -2, 1) != 's') {
$heading .= 's';
}
$heading .= ' move';
}
if (king_in_check($board_array, $current_player) && strpos($heading, 'mate') === false) {
$heading .= ' - <strong>Check!</strong>';
}
if ($goto != '') {
$turn_nr = goto_to_round($history, $goto);
$heading = "Round {$turn_nr}, {$heading}";
}
$heading = get_parameter(GET_COMMENT, $heading);
// Game title
if (isset($_GET[GET_WHITE])) {
$turn_nr = i_to_round($history);
$game_title = "{$name_white} vs. {$name_black} - Turn #{$turn_nr} - ";
}
$turn_nr = floor($turn_nr);
// History links
$next_goto = ($goto + 1) % (count_moves($history) + 1);
$history_next = update_href($href_this, GET_GOTO, $next_goto);
$next_goto = ($goto + count_moves($history)) % (count_moves($history) + 1);
$history_prev = update_href($href_this, GET_GOTO, $next_goto);
// Links for copy and paste
if (!isset($_GET[GET_NEW_GAME]) && !isset($_GET[GET_BASE_BOARD]) && isset($_SERVER['HTTP_REFERER']) && $_SERVER['QUERY_STRING'] != '' && $cmd_from == '' && $cmd_to == '') {
// Empty referer: Not reached by clicking a link in the browser
$t = str_replace('&', '&', $href_this);
$game_state_link = str_replace(' ', '+', $t);
$home_IPs = array('192.168.14.1', '213.47.94.176', 'local.at');
foreach ($home_IPs as $ip_address) {
if (strpos($game_state_link, $ip_address) !== false) {
$hmw_home_link = str_replace($ip_address, 'harald.ist.org/home', $game_state_link);
}
}
if ($hmw_home_link != '') {
$game_state_link = $hmw_home_link;
}
$game_state_link = str_replace('flip&', '', $game_state_link);
$game_state_link = str_replace('&', '&', $game_state_link);
}
debug_out("board_encoded = {$board_encoded}\n");
}
/**
* king_in_check() - return true, if king is in check
*/
function king_in_check($board_array, $current_player)
{
$ret = false;
$king_field = find_king($board_array, $current_player);
$opponents_pieces = find_movable_pieces($board_array, !$current_player);
// See, if any of the opponents pieces can capture the player's king
foreach ($opponents_pieces as $o) {
$captures = possible_move_list($board_array, !$current_player, $o);
$ret |= in_array($king_field, $captures);
}
return $ret;
}
