#!/usr/bin/php
<?php
// Takes the contents of a file, splits it into an array of lines, removes extra
// whitespace in the lines, and returns it back as an array of lines.
function cleanup_program($program) {
    $lines = explode("\n", $program);
    foreach ($lines as $line_number => $line) {
        $line = trim($line);
        $line = preg_replace('/ +/', ' ', $line); // No need for more than one space
        $line = str_replace("\t", '', $line);    
        $lines[$line_number] = $line;
    }
    return $lines;
}

// Displays an error message and quits
function show_error($error_txt, $line_number, $program_file) {
    die ("*Error* $error_txt (Line #$line_number in $program_file)\n");
}

// Compares a string to all the reserved words of the language
function is_reserved($string) {
    $keywords = array('jump', 'if', 'output', 'input', 'myself', 'not', 'or');
    foreach ($keywords as $keyword) {
        if ($keyword == $string) {
            return true;
        }
    }
    return false;
}

// Removes an element from an array
function array_remove(&$array, $element) {
    $new_array = array();
    foreach ($array as $key => $value) {
        if ($value != $element) {
            $new_array[$key] = $value;
        }
    }
    $array = $new_array;
}

// Checks if a variable exists and has joined the channel
function check_variable($var_name, $channel, $line_number, $channel_filename) {
    global $variables;
    if (!isset($variables[$var_name])) {
        show_error('This (un)voiced doesn\'t exist!', $line_number, $channel_filename);
    }
    if (!in_array($channel, $variables[$var_name]['channels'])) { show_error('This (un)voiced hasn\'t joined.', $line_number, $channel_filename); }
}

if ($argc != 2) {
    die ("Usage: $argv[0] <inputfile>\n");
}

// Open the main .irc file
if (!file_exists($argv[1])) {
    die ("File '$argv[1]' doesn't exist.\n");
}
$main_file_contents = file_get_contents($argv[1]);
$main_program = cleanup_program($main_file_contents);

// Get the information about the program
$program = array();
$program['channels'] = array();
foreach ($main_program as $line_num => $current_line) {
    if (preg_match('/^\/nick .+$/', $current_line)) {
        $parts = explode(' ', $current_line);
        if (count($parts) > 2) { show_error('Nick cannot contain spaces.', $line_num+1, $argv[1]); }
        $program['name'] = $parts[1];
        if (is_reserved($program['name'])) { show_error('That name is reserved.', $line_num+1, $argv[1]); }
    } else if (preg_match('/^\/join .+$/', $current_line)) {
        // Make sure they do things in the right order
        if (!isset($program['name'])) { show_error('Must set your nick before you can join channels.', $line_num+1, $argv[1]); }
        if (isset($program['error_msg'])) { show_error('You can\'t join channels after /quitting.', $line_num+1, $argv[1]); }
        
        // "/join" is the zeroth part, the channel name is the first part.
        $parts = explode(' ', $current_line);
        if (count($parts) > 2) { show_error('Channel name cannot contain spaces.', $line_num+1, $argv[1]); }
        if ($parts[1][0] != '#') { show_error('Channel name must start with #.', $line_num+1, $argv[1]); }
        array_push($program['channels'], $parts[1]);
    } else if (preg_match('/^\/quit .+$/', $current_line)) {
        if (!isset($program['name'])) { show_error('You can\'t quit until you /nick.', $line_num+1, $argv[1]); }
        $program['error_msg'] = substr($current_line, 6);
    } else if ($current_line != '') {
        show_error('There\'s something wrong with this line.', $line_num+1, $argv[1]);
    }
}

// Make sure we have the information
if (!isset($program['name'])) { show_error('This program doesn\'t have a name. Remember to /nick.', $line_num+1, $argv[1]); }
if (!isset($program['error_msg'])) { show_error('There is no default error message. Remember to /quit.', $line_num+1, $argv[1]); }
if (count($program['channels']) == 0) { die($program['error_msg']."\n"); }

// Escape special chars/punctuation chars for use in regex
$program['regex_name'] = preg_replace('/([^a-zA-Z0-9]{1})/', '\\\$1', $program['name']);

// Open all the channels and get them ready for interpreting
$channels = array();
foreach ($program['channels'] as $channel) {
    $channel_filename = substr($channel, 1).'.irc';
    if (!file_exists($channel_filename)) {
        die ("File '$channel_filename' doesn't exist.\n");
    }
    $channel_contents = file_get_contents($channel_filename);
    $channels[$channel]['lines'] = cleanup_program($channel_contents);
    $channels[$channel]['pc'] = 0; // Keeps track of which line it's on
    $channels[$channel]['variables'];
    $channels[$channel]['regex_name'] = preg_replace('/([^a-zA-Z0-9]{1})/', '\\\$1', $channel);
    $channels[$channel]['return_to'] = array();
    
    // Get the channel's labels
    $channels[$channel]['labels'] = array();
    foreach ($channels[$channel]['lines'] as $line_number => $line) {
        if (preg_match('/^\* '.$program['regex_name'].' changes topic to \'(.+)\'$/', $line, $matches)) {
            $channels[$channel]['labels'][$matches[1]] = $line_number+1;
        }
    }

    // Check the first line of the channel code, it should be code to join
    if (!preg_match('/^\* '.$program['regex_name'].' has joined '.$channels[$channel]['regex_name'].'$/', $channels[$channel]['lines'][0])) {
        show_error('Program name must join channel in first line of channel.', 1, $channel_filename);
    }
    $channels[$channel]['pc'] = 1;
}

// Start executing channel code
$quit_irc = false;
$variables = array();
while (count($channels) > 0 && !$quit_irc) {
    foreach ($channels as $channel_name => $this_channel) {
        $line = $this_channel['lines'][$this_channel['pc']];
        $channel_filename = substr($channel_name, 1).'.irc';
        $line_number = $this_channel['pc']+1;
    
        // Is it a comment?
        $is_comment = false;
        if (preg_match('/^<([^ ]+)> .+$/', $line, $matches)) {
            $var_name = $matches[1];
            if (!is_reserved($var_name)) {
                check_variable($var_name, $channel_name, $line_number, $channel_filename);
                if (!$variables[$var_name]['voiced']) {
                    $is_comment = true;
                }
            }
        }
        
        if ($line == '') {
            $is_comment = true;
        }
        
        if (!$is_comment) {
            // * [voiced] has joined [channel_name]
            if (preg_match('/^\* ([^ ]+) has joined '.$this_channel['regex_name'].'$/', $line, $matches)) {
                $var_name = $matches[1];
                if (is_reserved($var_name)) {
                    show_error('This is a reserved word.', $line_number, $channel_filename);
                }
                if (isset($variables[$var_name])) {
                    if (in_array($channel_name, $variables[$var_name]['channels'])) { show_error('This (un)voiced has already joined.', $line_number, $channel_filename); }
                } else {
                    $variables[$var_name]['voiced'] = false;
                    $variables[$var_name]['value'] = 0;
                    $variables[$var_name]['channels'] = array();
                }                
                array_push($variables[$matches[1]]['channels'], $channel_name);
                
            // * [voiced] has left [channel_name]
            } else if (preg_match('/^\* ([^ ]+) has left '.$this_channel['regex_name'].'$/', $line, $matches)) {
                $var_name = $matches[1];
                if (isset($variables[$var_name])) {
                    if (!in_array($channel_name, $variables[$var_name]['channels'])) { show_error('This (un)voiced hasn\'t joined.', $line_number, $channel_filename); }
                }
                array_remove($variables[$var_name]['channels'], $channel_name);
                if (count($variables[$var_name]['channels']) == 0) {
                    unset($variables[$var_name]);
                }
                
            // * [name] has left [channel_name]
            } else if (preg_match('/^\* '.$program['regex_name'].' has left '.$channels[$channel_name]['regex_name'].'$/', $line)) {
                $kill_channel = true;
                
            // * [name] has quit IRC (Quit: [error_message])
            } else if (preg_match('/^\* '.$program['regex_name'].' has quit IRC \(Quit: (.*)\)$/', $line, $matches)) {
                $quit_irc = true;
                $program['error_msg'] = $matches[1];
                
            // * [name] sets mode: +v [voiced]
            } else if (preg_match('/^\* '.$program['regex_name'].' sets mode: \+v (.+)$/', $line, $matches)) {
                $var_name = $matches[1];
                if (isset($variables[$var_name])) {
                    if (!in_array($channel_name, $variables[$var_name]['channels'])) { show_error('This (un)voiced hasn\'t joined.', $line_number, $channel_filename); }
                }
                $variables[$var_name]['voiced'] = true;
                
            // * [name] changes topic to '[topic]'
            } else if (preg_match('/^\* '.$program['regex_name'].' changes topic to \'(.+)\'$/', $line, $matches)) {
                $channels[$channel_name]['labels'][$matches[1]] = $channels[$channel_name]['pc'];
                
            // <jump> Let's talk about [topic].
            } else if (preg_match('/^<jump> Let\'s talk about (.+)\.$/', $line, $matches)) {
                $topic = $matches[1];
                if (isset($channels[$channel_name]['labels'][$topic])) {
                    $channels[$channel_name]['pc'] = $channels[$channel_name]['labels'][$topic]-1;
                } else {
                    show_error('That topic doesn\'t exist.', $line_number, $channel_filename);
                }
                
            // <jump> Off topic: Let's talk about [topic].
            } else if (preg_match('/^<jump> Off topic: Let\'s talk about (.+)\.$/', $line, $matches)) {
                $topic = $matches[1];
                if (isset($channels[$channel_name]['labels'][$topic])) {
                    $jump_to = $channels[$channel_name]['labels'][$topic];
                    array_push($channels[$channel_name]['return_to'], $channels[$channel_name]['pc']);
                    $channels[$channel_name]['pc'] = $jump_to-1;
                } else {
                    show_error('That topic doesn\'t exist.', $line_number, $channel_filename);
                }
                
            // <jump> They're talking about [topic] in [channel].
            } else if (preg_match('/^<jump> They\'re talking about (.+) in (\#[^ ]+)\.$/', $line, $matches)) {
                $topic = $matches[1];
                $channel = $matches[2];
                
            // <jump> Let's get back on topic.
            } else if (preg_match('/^<jump> Let\'s get back on topic.$/', $line)) {
                $return_to = array_pop($channels[$channel_name]['return_to']);
                if (!$return_to) {
                    show_error('There\'s no topic to get back onto.', $line_number, $channel_filename);
                }
                $channels[$channel_name]['pc'] = $return_to;
            
            // <if> [voiced], are you [condition]?
            } else if (preg_match('/^<if> ([^ ]+), are you (.+)\?$/', $line, $matches)) {
                $var_name = $matches[1];
                $condition = $matches[2];
                
                if (!isset($variables[$var_name])) {
                    show_error('This (un)voiced doesn\'t exist!', $line_number, $channel_filename);
                }
                
                // not equal to [value]
                if (preg_match('/^not equal to ([^ ]+)$/', $condition, $matches)) {
                    $var2_name = $matches[1];
                    if (!isset($variables[$var2_name]) && !is_numeric($var2_name)) {
                        show_error('This (un)voiced doesn\'t exist!', $line_number, $channel_filename);
                    }
                    if (is_numeric($var2_name)) {
                        $condition_result = !($variables[$var_name]['value'] != intval($var2_name));
                    } else {
                        $condition_result = !($variables[$var_name]['value'] != $variables[$var2_name]['value']);
                    }
                    if ($condition_result == true) {
                        $channels[$channel_name]['pc']++;
                    }
                
                // equal to [value]
                } else if (preg_match('/^equal to ([^ ]+)$/', $condition, $matches)) {
                    $var2_name = $matches[1];
                    if (!isset($variables[$var2_name]) && !is_numeric($var2_name)) {
                        show_error('This (un)voiced doesn\'t exist!', $line_number, $channel_filename);
                    }
                    if (is_numeric($var2_name)) {
                        $condition_result = !($variables[$var_name]['value'] == intval($var2_name));
                    } else {
                        $condition_result = !($variables[$var_name]['value'] == $variables[$var2_name]['value']);
                    }
                    if ($condition_result == true) {
                        $channels[$channel_name]['pc']++;
                    }
                
                // equal to or greater than [value]
                } else if (preg_match('/^equal to or greater than ([^ ]+)$/', $condition, $matches)) {
                    $var2_name = $matches[1];
                    if (!isset($variables[$var2_name]) && !is_numeric($var2_name)) {
                        show_error('This (un)voiced doesn\'t exist!', $line_number, $channel_filename);
                    }
                    if (is_numeric($var2_name)) {
                        $condition_result = !($variables[$var_name]['value'] >= intval($var2_name));
                    } else {
                        $condition_result = !($variables[$var_name]['value'] >= $variables[$var2_name]['value']);
                    }
                    if ($condition_result == true) {
                        $channels[$channel_name]['pc']++;
                    }
                
                // equal to or less than [value]
                } else if (preg_match('/^equal to or less than ([^ ]+)$/', $condition, $matches)) {
                    $var2_name = $matches[1];
                    if (!isset($variables[$var2_name]) && !is_numeric($var2_name)) {
                        show_error('This (un)voiced doesn\'t exist!', $line_number, $channel_filename);
                    }
                    if (is_numeric($var2_name)) {
                        $condition_result = !($variables[$var_name]['value'] <= intval($var2_name));
                    } else {
                        $condition_result = !($variables[$var_name]['value'] <= $variables[$var2_name]['value']);
                    }
                    if ($condition_result == true) {
                        $channels[$channel_name]['pc']++;
                    }
                
                // greater than [value]
                } else if (preg_match('/^greater than ([^ ]+)$/', $condition, $matches)) {
                    $var2_name = $matches[1];
                    if (!isset($variables[$var2_name]) && !is_numeric($var2_name)) {
                        show_error('This (un)voiced doesn\'t exist!', $line_number, $channel_filename);
                    }
                    if (is_numeric($var2_name)) {
                        $condition_result = !($variables[$var_name]['value'] > intval($var2_name));
                    } else {
                        $condition_result = !($variables[$var_name]['value'] > $variables[$var2_name]['value']);
                    }
                    if ($condition_result == true) {
                        $channels[$channel_name]['pc']++;
                    }
                
                // less than [value]
                } else if (preg_match('/^less than ([^ ]+)$/', $condition, $matches)) {
                    $var2_name = $matches[1];
                    if (!isset($variables[$var2_name]) && !is_numeric($var2_name)) {
                        show_error('This (un)voiced doesn\'t exist!', $line_number, $channel_filename);
                    }
                    if (is_numeric($var2_name)) {
                        $condition_result = !($variables[$var_name]['value'] < intval($var2_name));
                    } else {
                        $condition_result = !($variables[$var_name]['value'] < $variables[$var2_name]['value']);
                    }
                    if ($condition_result == true) {
                        $channels[$channel_name]['pc']++;
                    }
                
                // None of the above.
                } else {
                    show_error('Bad condition.', $line_number, $channel_filename);
                }
                
            // <output> What's your value, [voiced]?
            } else if (preg_match('/^<output> What\'s your value, ([^ ]+)\?$/', $line, $matches)) {
                $var_name = $matches[1];
                if (!isset($variables[$var_name])) { show_error('This (un)voiced doesn\'t exist!', $line_number, $channel_filename); }
                echo $variables[$var_name]['value'];
                
            // <output> What's your character, [voiced]?
            } else if (preg_match('/^<output> What\'s your character, ([^ ]+)\?$/', $line, $matches)) {
                $var_name = $matches[1];
                if (!isset($variables[$var_name])) { show_error('This (un)voiced doesn\'t exist!', $line_number, $channel_filename); }
                echo chr($variables[$var_name]['value']);
                
            // <input> Hey, [voiced].
            } else if (preg_match('/^<input> Hey, ([^ ]+)\.$/', $line, $matches)) {
                $var_name = $matches[1];
                if (!isset($variables[$var_name])) { show_error('This (un)voiced doesn\'t exist!', $line_number, $channel_filename); }
                $variables[$var_name]['value'] = ord(fread(STDIN, 1));
                
            // <[voiced]> I'm not [value].
            } else if (preg_match('/^<([^ ]+)> I\'m not ([^ ]+)\.$/', $line, $matches)) {
                $var_name = $matches[1];
                $value = $matches[2];
                check_variable($var_name, $channel_name, $line_number, $channel_filename);
                if (is_numeric($value)) {
                    $variables[$var_name]['value'] = ~intval($value);
                } else {
                    if (!isset($variables[$value])) { show_error('This variable doesn\'t exist.', $line_number, $channel_filename); }
                    $variables[$var_name]['value'] = ~$variables[$value]['value'];
                }
                
            // <[voiced]> I'm [value].
            } else if (preg_match('/^<([^ ]+)> I\'m ([^ ]+)\.$/', $line, $matches)) {
                $var_name = $matches[1];
                $value = $matches[2];
                check_variable($var_name, $channel_name, $line_number, $channel_filename);
                if (is_numeric($value)) {
                    $variables[$var_name]['value'] = intval($value);
                } else {
                    if (!isset($variables[$value])) { show_error('This variable doesn\'t exist.', $line_number, $channel_filename); }
                    $variables[$var_name]['value'] = $variables[$value]['value'];
                }
                
            // <[voiced]> I'm [value] [operation] [value].
            } else if (preg_match('/^<([^ ]+)> I\'m ([^ ]+) ([a-z ]+) ([^ ]+)\.$/', $line, $matches)) {
                $var_name = $matches[1];
                $value1 = $matches[2];
                $operation = $matches[3];
                $value2 = $matches[4];
                
                check_variable($var_name, $channel_name, $line_number, $channel_filename);
                
                if ($value1 == 'myself') { $value1 = $variables[$var_name]['value']; }
                if ($value2 == 'myself') { $value2 = $variables[$var_name]['value']; }
                
                if (!is_numeric($value1)) {
                    if (!isset($variables[$value1])) { show_error('This variable doesn\'t exist.', $line_number, $channel_filename); }
                    $value1 = $variables[$value1]['value'];
                }
                if (!is_numeric($value2)) {
                    if (!isset($variables[$value2])) { show_error('This variable doesn\'t exist.', $line_number, $channel_filename); }
                    $value2 = $variables[$value2]['value'];
                }
                
                switch ($operation) {
                    case 'plus':
                        $variables[$var_name]['value'] = $value1 + $value2;
                        break;
                    case 'minus':
                        $variables[$var_name]['value'] = $value1 - $value2;
                        break;
                    case 'times':
                        $variables[$var_name]['value'] = $value1 * $value2;
                        break;
                    case 'divided by':
                        if ($value2 == 0) { show_error('Division by zero.', $line_number, $channel_filename); }
                        $variables[$var_name]['value'] = $value1 / $value2;
                        break;
                    case 'to the power of':
                        $variables[$var_name]['value'] = pow($value1, $value2);
                        break;
                    case 'and':
                        $variables[$var_name]['value'] = $value1 & $value2;
                        break;
                    case 'or':
                        $variables[$var_name]['value'] = $value1 | $value2;
                        break;
                    case 'xor':
                        $variables[$var_name]['value'] = $value1 ^ $value2;
                        break;
                }
                
            // None of the above.
            } else {
                show_error('There\'s something wrong with this line.', $line_number, $channel_filename);
            }
        }
        
        $channels[$channel_name]['pc']++;
        
        if (count($channels[$channel_name]['lines']) < $channels[$channel_name]['pc'] || $kill_channel) {
            unset($channels[$channel_name]);
            $kill_channel = false;
            
            // Clean up variables that were in this channel
            foreach ($variables as $variable => $variable_info) {
                array_remove($variables[$variable]['channels'], $channel_name);
                if (count($variables[$variable]['channels']) == 0) {
                    unset($variables[$variable]);
                }
            }
        }
    }
}

echo $program['error_msg']."\n";
?>