mm.inc

<?php
// This file is part of Music Match.
// Copyright (C) 2022 David P. Anderson
//
// Music Match is free software; you can redistribute it and/or modify it
// under the terms of the GNU Lesser General Public License
// as published by the Free Software Foundation,
// either version 3 of the License, or (at your option) any later version.
//
// Music Match is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
// See the GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with Music Match.  If not, see <http://www.gnu.org/licenses/>.
// --------------------------------------------------------------------

// Music-match-specific utility functions and constants

define('DEBUG', false);

require_once("../inc/zip.inc");

// DB fields

// user: we use:
//      user.send_email to store prefs
//      user.expavg_time to store time of last email
//      user.venue to store name of picture file in pictures/

// ensemble_member.status

define('EM_PENDING',    0);
define('EM_APPROVED',   1);
define('EM_DECLINED',   2);
define('EM_REMOVED',    3);

// notify.type

// 1-4 are defined in forum_db.inc
// friend req, friend accept, pm, subscribed post

// NOTIFY_FRIEND_REQ
//  opaque is ID of other user
// NOTIFY_FRIEND_ACCEPT
//  opaque is ID of other user
// NOTIFY_PM
//  opaque is message ID
// NOTIFY_SUBSCRIBED_POST
//  opaque is thread ID

define('NOTIFY_FOLLOW',         1);
define('NOTIFY_SEARCH',         5);
    // a previous search has new result
    // opaque and id2 are zero
define('NOTIFY_ENS_DEL',        6);
    // an ensemble you're in was deleted
    // opaque is ens ID
define('NOTIFY_PROFILE',        7);
    // someone you follow changed a profile
    // opaque is user ID; id2 is role
define('NOTIFY_ENS_JOIN_REQ',   8);
    // someone asked to join an ensemble you founded
    // opaque is ens ID, id2 is user ID
define('NOTIFY_ENS_JOIN_REPLY', 9);
    // your ensemble join request was accepted or declined
    // opaque is ens ID; id2 is 1 if accepted
define('NOTIFY_ENS_REMOVE',     10);
    // you were removed from an ensemble
    // opaque is ens ID
define('NOTIFY_ENS_QUIT',       11);
    // someone quit an ensemble you founded
    // opaque is ens ID; id2 is user ID
define('NOTIFY_LOOKING_FOR_YOU', 12);
    // user X did a search for which you are in the top N results
    // opaque is the role of the search, id2 is X.id

// values for private_messages.opened: recipient status
define('PM_UNREAD',     0);
define('PM_READ',       1);
define('PM_DELETED',    2);

// values for "role"; each has an associated JSON structure
//
define('COMPOSER', 0);
define('PERFORMER', 1);
define('TECHNICIAN', 2);
define('ENSEMBLE', 3);
define('TEACHER', 4);

// removing or changing keys will invalidate existing profiles

define('STYLE_LIST', array(
    'baroque' => 'Baroque',
    'classical' => 'Classical',
    'romantic' => 'Romantic',
    'impressionist' => 'Impressionist',
    'minimalist' => 'Minimalist',
    'modern' => 'Modern',
    'new_age' => 'New Age',
    'atonal' => 'Atonal'
));

define('INST_LIST_COARSE', array(
    'keyboard' => 'Piano/organ/keyboard',
    'woodwinds' => 'Woodwinds',
    'strings' => 'Strings',
    'brass' => 'Brass',
    'percussion' => 'Percussion',
    'vocal' => 'Vocal'
));

define('INST_LIST_FINE', array(
    'bass' => 'Double bass',
    'bassoon' => 'Bassoon',
    'cello' => 'Cello',
    'clarinet' => 'Clarinet',
    'bass' => 'Double bass',
    'flute' => 'Flute',
    'french_horn' => 'French horn',
    'guitar' => 'Guitar',
    'harp' => 'Harp',
    'harpsichord' => 'Harpsichord',
    'oboe' => 'Oboe',
    'organ' => 'Organ',
    'percussion' => 'Percussion',
    'piano' => 'Piano',
    'saxophone' => 'Saxophone',
    'trombone' => 'Trombone',
    'trumpet' => 'Trumpet',
    'tuba' => 'Tuba',
    'viola' => 'Viola',
    'violin' => 'Violin',
    'vocal_soprano' => 'Vocal (soprano)',
    'vocal_alto' => 'Vocal (alto)',
    'vocal_tenor' => 'Vocal (tenor, countertenor)',
    'vocal_bass' => 'Vocal (bass, baritone)',
));

define('LEVEL_LIST', array(
    'beg' => 'Beginning',
    'int' => 'Intermediate',
    'adv' => 'Advanced'
));

define('ENSEMBLE_TYPE_LIST', array(
    'chamber' => 'Chamber group',
    'choir' => 'Choir',
    'duo' => 'Duo',
    'opera' => 'Opera company',
    'orchestra' => 'Orchestra',
));

define('COMPOSE_FOR_LIST', array_merge(ENSEMBLE_TYPE_LIST, ['soloist'=>'Soloist']));

define('TECH_AREA_LIST', array(
    'score_edit' => 'Score editing',
    'recording' => 'Recording',
    'post_production' => 'Post-production',
    'live_stream' => 'Live streaming',
));

define('PROGRAM_LIST', array(
    'ableton' => 'Ableton Live',
    'ardour' => 'Ardour',
    'finale' => 'Finale',
    'garage_band' => 'Garage Band',
    'logic_pro' => 'Logic Pro',
    'musescore' => 'MuseScore',
    'pro_tools' => 'Pro Tools',
    'reaper' => 'Reaper',
    'sibelius' => 'Sibelius',
));

define ('TOPIC_LIST', array_merge(INST_LIST_COARSE, [
    'theory' => 'Theory and harmony',
    'composition' => 'Composition'
]));

define ('WHERE_LIST', [
    'teacher' => "Teacher's place",
    'student' => "Student's place",
    'school' => 'School',
    'online' => 'Online'
]);

// ensemble type may be custom
//
function ensemble_type_str($type) {
    if (array_key_exists($type, ENSEMBLE_TYPE_LIST)) {
        return ENSEMBLE_TYPE_LIST[$type];
    } else {
        return $type;
    }
}

// ---------- Functions for generating and parsing forms (search, edit)

// text for custom fields

define('INST_ADD', 'Other instrument');
define('STYLE_ADD', 'Other style');
define('INFLUENCE_ADD', 'Add influence');
define('LINK_ADD_URL', 'Add link: URL');
define('LINK_ADD_DESC', 'Description');
define('ENSEMBLE_TYPE_ADD', 'Other ensemble type');
define('TECH_AREA_ADD', 'Other area');
define('PROGRAM_ADD', 'Other program');
define('TOPIC_ADD', 'Other topic');

// ----- checkbox stuff

// return a list of (tag/name/checked) triples (for form_checkboxes())
// for a predefined list of items (like instruments)
//
function items_list($list, $current, $prefix) {
    $x = array();
    foreach ($list as $tag => $name) {
        $x[] = array(sprintf("%s_%s", $prefix, $tag), $name, in_array($tag, $current));
    }
    return $x;
}

// make all/none links for groups of checkboxes
//
function checkbox_all_none($list, $prefix) {
    $x = sprintf('<script>
        function set_all_%s(val) {
        ', $prefix
    );
    foreach ($list as $tag => $name) {
        $x .= sprintf('document.getElementsByName("%s_%s")[0].checked=val;
            ', $prefix, $tag
        );
    }
    $x .= sprintf('
        }
        </script>
        <small><a href=# onclick="set_all_%s(true)">all</a> &middot
        <a href=# onclick="set_all_%s(false)">none</a></small>
        ', $prefix, $prefix
    );
    return $x;
}

// Make checkbox list for custom (user-defined) items
//
function items_custom($current, $prefix) {
    $x = array();
    foreach ($current as $i=>$name) {
        $x[] = array(
            sprintf("%s_%d", $prefix, $i),
            $name,
            true
        );
    }
    return $x;
}

// same, for user-supplied links
//
function items_link($current, $prefix) {
    $x = array();
    foreach ($current as $i=>$link) {
        $x[] = array(
            sprintf("%s_%d", $prefix, $i),
            sprintf("%s -> %s", $link->desc, $link->url),
            true
        );
    }
    return $x;
}

// return the items in $list for which $prefix_item is set
//
function parse_list($list, $prefix) {
    $x = array();
    foreach ($list as $tag=>$name) {
        if (post_str(sprintf("%s_%s", $prefix, $tag), true)) {
            $x[] = $tag;
        }
    }
    return $x;
}

// return the items in $current for which $prefix_item is set;
// if $prefix_new is present, include that as well;
// apply strip_tags() to it.
//
function parse_custom($current, $prefix, $exclude) {
    $x = array();
    foreach ($current as $i=>$name) {
        if (post_str(sprintf("%s_%d", $prefix, $i), true)) {
            $x[] = $name;
        }
    }
    $y = post_str(sprintf("%s_new", $prefix), true);
    if ($y && $y!=$exclude) {
        $x[] = strip_tags($y);
    }
    return $x;
}

// parse a boolean checkbox
//
function parse_post_bool($name) {
    return post_str($name, true)?1:0;
}

// ------- radio

// convert array to list of pairs
//
function radio_list($list) {
    $x = array();
    foreach ($list as $tag=>$name) {
        $x[] = array($tag, $name);
    }
    return $x;
}

// show yes/no/either radio buttons for a bool
//
function radio_bool($label, $name) {
    form_radio_buttons(
        $label,
        $name,
        array(
            array('yes', 'Yes'),
            array('no', 'No'),
            array('either', 'Either')
        ),
        'either'
    );
}

// ------- other

// return stuff to put into a text <input> to give it a value
// that goes away if you click there
//
function text_input_default($t) {
    return sprintf('
        onfocus="if(this.value==\'%s\'){this.value=\'\';}"
        onblur="if(this.value==\'\'){this.value=\'%s\';}"',
        $t, $t
    );
}

// If "close" was specified in a search (user or ensemble),
// decide what this means, and tell the user
//
function handle_close($form_args, $req_user) {
    $close_country = null;
    $close_zip = 0;
    if ($form_args->close) {
        $close_country = $req_user->country;
        if ($req_user->country) {
            if ($req_user->country == 'United States') {
                if ($req_user->postal_code){
                    $close_zip = str_to_zip($req_user->postal_code);
                    if ($close_zip) {
                        echo "<p>Distance estimates are based on your postal code ($req_user->postal_code)<p>";
                    } else {
                        echo "<p>Your postal code ($req_user->postal_code) isn't in our database.  Showing results from the United States.<p>";
                    }
                } else {
                    echo "<p>You haven't <a href=home.php>specified your postal code.  Showing results from the United States.<p>";
                }
            } else {
                echo "<p>Showing only results from $req_user->country.<p>";
            }
        } else {
            echo "<p>You haven't <a href=home.php>specified your country</a>, so we don't know who's close to you.<p>";
        }
    }
    return [$close_country, $close_zip];
}

// handle the upload of an MP3 file
// $id is that of either a user or an ensemble
//
function handle_audio_signature_upload($profile, $profile2, $role, $id) {
    if ($profile->signature_filename) {
        if (post_str('signature_check', true)) {
            $profile2->signature_filename = $profile->signature_filename;
        } else {
            $profile2->signature_filename = '';
            unlink(sprintf('%s/%d.mp3', role_dir($role), $id));
        }
    } else {
        $sig_file = $_FILES['signature_add'];
        $sig_name = $sig_file['tmp_name'];
        $orig_name = $sig_file['name'];
        if ($orig_name) {
            if (is_uploaded_file($sig_name)) {
                $finfo = finfo_open(FILEINFO_MIME_TYPE);
                if (finfo_file($finfo, $sig_name) != 'audio/mpeg') {
                    error_page("$orig_name is not an MP3 file.");
                }
                $new_name = sprintf('%s/%d.mp3',
                    role_dir($role), $id
                );
                if (!move_uploaded_file($sig_name, $new_name)) {
                    error_page("Couldn't move uploaded file.");
                }
                $profile2->signature_filename = $orig_name;
            } else {
                error_page("Couldn't upload $orig_name; it may be too large.");
            }
        }
    }
    return $profile2;
}

// Validate a link (URL/desc pair) in a form
// Add name=x onsubmit="return validate_link()" in the form element
//
function validate_link_script($form_name, $url_name, $desc_name) {
    echo sprintf('
        <script>
            function validate_link() {
              let url = document.forms["%s"]["%s"].value;
              let desc = document.forms["%s"]["%s"].value;
              if (url && url!= "%s") {
                if (!url.startsWith("http")) {
                  alert("Link URL must start with http:// or https://");
                  return false;
                }
                if (!desc || desc==="%s") {
                  alert("Link description must be non-blank");
                  return false;
                }
              }
              return true;
            }
        </script>
        ',
        $form_name, $url_name,
        $form_name, $desc_name,
        LINK_ADD_URL,
        LINK_ADD_DESC
    );
}

// ---------- reading and writing profiles

// example composer profile
//
//  {
//      "style": [
//          "modern",
//          "atonal"
//      ],
//      "style_custom": [
//          "Death Metal",
//      ],
//      "inst": [
//          "keyboard"
//      ],
//      "inst_custom": [
//          "Piano Trio"
//      ],
//      "level": [
//          1,
//          2
//      ]
//      "influence": [
//          "Igor Stravinsky"
//      ],
//      "link": [
//          {
//              "url": "https://a.b.c",
//              "desc": "Some of my works"
//          },
//          ...
//      ],
//      "signature_filename": "foo.mp3",
//      "comment": "blah blah"
//  }

function role_dir($role) {
    switch ($role) {
    case COMPOSER: return "composer";
    case PERFORMER: return "performer";
    case TECHNICIAN: return "technician";
    case ENSEMBLE: return "ensemble";
    case TEACHER: return "teacher";
    default: die("bad role");
    }
}

function role_name($role) {
    switch ($role) {
    case COMPOSER: return "Composer";
    case PERFORMER: return "Performer";
    case TECHNICIAN: return "Technician";
    case ENSEMBLE: return "Ensemble";
    case TEACHER: return "Teacher";
    default: die("bad role");
    }
}

// $id can be user ID or ensemble ID
//
function profile_exists($id, $role) {
    $dir = role_dir($role);
    $fname = "$dir/$id.json";
    return file_exists($fname);
}

function read_profile($id, $role) {
    $dir = role_dir($role);
    $fname = "$dir/$id.json";
    if (file_exists($fname)) {
        $p = json_decode(file_get_contents($fname));
    } else {
        $p = new StdClass;
    }
    switch ($role) {
    case COMPOSER:
        if (!array_key_exists('style', $p)) $p->style = array();
        if (!array_key_exists('style_custom', $p)) $p->style_custom = array();
        if (!array_key_exists('inst', $p)) $p->inst = array();
        if (!array_key_exists('inst_custom', $p)) $p->inst_custom = array();
        if (!array_key_exists('ens_type', $p)) $p->ens_type = array();
        if (!array_key_exists('ens_type_custom', $p)) $p->ens_type_custom = array();
        if (!array_key_exists('level', $p)) $p->level = array();
        if (!array_key_exists('signature_filename', $p)) $p->signature_filename = '';
        if (!array_key_exists('link', $p)) $p->link = array();
        if (!array_key_exists('comp_paid', $p)) $p->comp_paid = 0;
        if (!array_key_exists('description', $p)) $p->description = '';
        break;
    case PERFORMER:
        if (!array_key_exists('style', $p)) $p->style = array();
        if (!array_key_exists('style_custom', $p)) $p->style_custom = array();
        if (!array_key_exists('inst', $p)) $p->inst = array();
        if (!array_key_exists('inst_custom', $p)) $p->inst_custom = array();
        if (!array_key_exists('level', $p)) $p->level = array();
        if (!array_key_exists('signature_filename', $p)) $p->signature_filename = '';
        if (!array_key_exists('link', $p)) $p->link = array();
        if (!array_key_exists('perf_reg', $p)) $p->perf_reg = 0;
        if (!array_key_exists('perf_paid', $p)) $p->perf_paid = 0;
        if (!array_key_exists('description', $p)) $p->description = '';
        break;
    case TECHNICIAN:
        if (!array_key_exists('tech_area', $p)) $p->tech_area = array();
        if (!array_key_exists('tech_area_custom', $p)) $p->tech_area_custom = array();
        if (!array_key_exists('program', $p)) $p->program = array();
        if (!array_key_exists('program_custom', $p)) $p->program_custom = array();
        if (!array_key_exists('tech_paid', $p)) $p->tech_paid = 0;
        if (!array_key_exists('description', $p)) $p->description = '';
        break;
    case ENSEMBLE:
        if (!array_key_exists('description', $p)) $p->description = '';
        if (!array_key_exists('type', $p)) $p->type = '';
        if (!array_key_exists('style', $p)) $p->style = array();
        if (!array_key_exists('style_custom', $p)) $p->style_custom = array();
        if (!array_key_exists('inst', $p)) $p->inst = array();
        if (!array_key_exists('inst_custom', $p)) $p->inst_custom = array();
        if (!array_key_exists('level', $p)) $p->level = array();
        if (!array_key_exists('signature_filename', $p)) $p->signature_filename = '';
        if (!array_key_exists('link', $p)) $p->link = array();
        if (!array_key_exists('seeking_members', $p)) $p->seeking_members = 0;
        if (!array_key_exists('perf_reg', $p)) $p->perf_reg = 0;
        if (!array_key_exists('perf_paid', $p)) $p->perf_paid = 0;
        break;
    case TEACHER:
        if (!array_key_exists('topic', $p)) $p->topic = array();
        if (!array_key_exists('topic_custom', $p)) $p->topic_custom = array();
        if (!array_key_exists('style', $p)) $p->style = array();
        if (!array_key_exists('style_custom', $p)) $p->style_custom = array();
        if (!array_key_exists('level', $p)) $p->level = array();
        if (!array_key_exists('link', $p)) $p->link = array();
        if (!array_key_exists('where', $p)) $p->where = array();
        if (!array_key_exists('description', $p)) $p->description = '';
        break;
    }
    return $p;
}

function write_profile($user_id, $profile, $role) {
    $dir = role_dir($role);
    $fname = "$dir/$user_id.json";
    $f = fopen($fname, "w");
    fwrite($f, json_encode($profile, JSON_PRETTY_PRINT));
    fclose($f);
}

function delete_mm_profile($id, $role) {
    $dir = role_dir($role);
    $fname = "$dir/$id.json";
    @unlink($fname);
}

function get_profiles($role) {
    $dir = role_dir($role);
    $x = array();
    foreach(scandir($dir) as $f) {
        if (str_starts_with($f, '.')) continue;
        if (!str_ends_with($f, '.json')) continue;
        $id = (int)$f;
        $x[$id] = read_profile($id, $role);
    }
    return $x;
}

// ------------ display -------------


// Javascript for audio on search results
//
function enable_audio() {
echo '
<script language="javascript" type="text/javascript">
function play_sound(id) {
    var audio = document.getElementById(id);
    audio.currentTime = 0;
    audio.play();
}

function stop_sound(id) {
    var audio = document.getElementById(id);
    audio.pause();
}
</script>
';
}

// show a list of items (instruments, styles etc.) as a string
//
function lists_to_string($master_list, $list, $list2=null, $sep=',') {
    $x = "";
    $first = true;
    foreach ($list as $i) {
        if ($first) {
            $first = false;
        } else {
            $x .= $sep;
        }
        $x .= ' ';
        $x .= $master_list[$i];
    }
    if (!$list2) {
        return $x;
    }
    foreach ($list2 as $i) {
        if ($first) {
            $first = false;
        } else {
            $x .= $sep;
        }
        $x .= ' ';
        $x .= "$i";
    }
    return $x;
}

function links_to_string($links, $sep=',') {
    $x = "";
    $first = true;
    foreach ($links as $link) {
        if ($first) {
            $first = false;
        } else {
            $x .= $sep;
        }
        $x .= sprintf(" <a href=%s>%s</a>", $link->url, $link->desc);
    }
    return $x;
}

// return string showing country and - if relevant - distance
//
function country_distance($user, $dist, $sep=' ') {
    if ($dist >= 0) {
        $d = (int)$dist;
        return sprintf(
            "%s%s<small>(%d mile%s from you)</small>",
            $user->country,
            $sep,
            $d,
            $d==1?'':'s'
        );
    } else {
        return $user->country;
    }
}

// button styles
//
define('BUTTON_BIG',
    //['btn', '#00bc8c', 'black', '<font size=+2><b>', '</b></font>']
    ['btn', '#375a7f', 'white', '<font size=+2><b>', '</b></font>']
);
define('BUTTON_NORMAL',
    ['btn', ' #375a7f', 'white', '<font size=+0>', '</font>']
);
define('BUTTON_DANGER',
    ['btn', ' #ff6060', 'white', '<font size=+0>', '</font>']
);
define('BUTTON_SMALL',
    ['btn-sm', ' #375a7f', 'white', '<font size=+0>', '</font>']
);

function mm_button_text($url, $label, $style=BUTTON_NORMAL) {
    return sprintf(
        '<a class="%s" style="background-color:%s; color:%s" href=%s>%s%s%s</a>',
        $style[0], $style[1], $style[2], $url, $style[3], $label, $style[4]
    );
}

function mm_show_button($url, $label, $style=BUTTON_NORMAL) {
    echo mm_button_text($url, $label, $style);
}

// ------------ utilities -------------

// column header for Music Sample
//
function music_sample_header($role=PERFORMER) {
    $x = ($role==COMPOSER)?'Composition':'Performance';
    return "<nobr>$x sample</nobr>&nbsp;&nbsp;&nbsp;<br><nobr><small>To play: click &nbsp; <img height=18px src=note.png> &nbsp; and hover</nobr>&nbsp;&nbsp;&nbsp;";
}

// if user hasn't validated their email addr, ask them to do so
//
function mm_get_logged_in_user() {
    $user = get_logged_in_user();
    if ($user && !$user->email_validated) {
        Header("Location: signup.php?action=verify");
    }
    return $user;
}

function str_starts_with ($haystack, $needle) {
    return strpos( $haystack , $needle ) === 0;
}

function str_ends_with($haystack, $needle) {
    $length = strlen($needle);
    return $length > 0 ? substr($haystack, -$length) === $needle : true;
}

function compare_value($p1, $p2) {
    if ($p1->value > $p2->value) {
        return -1;
    } else if ($p1->value < $p2->value) {
        return 1;
    } else {
        return 0;
    }
}

function user_distance($u1, $u2) {
    if ($u1->country != 'United States') return -1;
    if ($u2->country != 'United States') return -1;
    $z1 = str_to_zip($u1->postal_code);
    if (!$z1) return -1;
    $z2 = str_to_zip($u2->postal_code);
    if (!$z2) return -1;
    return zip_dist($z1, $z2);
}

function em_status_string($status) {
    switch ($status) {
    case EM_PENDING: return 'Membership request pending';
    case EM_APPROVED: return 'Member';
    case EM_DECLINED: return 'Membership request declined';
    case EM_REMOVED: return 'Membership removed';
    }
    return 'unknown';
}

function home_button() {
    mm_show_button("home.php", "Return to my home page");
}

function join_button() {
    echo "<p>";
    mm_show_button("signup.php", "JOIN", BUTTON_BIG);
}

// we use user.seti_total_cpu to store last visit time
//
function update_visit_time($user) {
    if (!$user) return;
    $now = time();
    if ($user->seti_total_cpu < $now - 600) {
        $user->update("seti_total_cpu=$now");
    }
}

function get_visit_time($user) {
    return $user->seti_total_cpu;
}

function interval_to_str($x) {
    $d = 86400;
    $w = 7*86400;
    $m = 31*86400;
    $y = 365*86400;
    if ($x < $d) return "Today";
    if ($x < 2*$d) return "Yesterday";
    if ($x < 2*$w) return sprintf("%d days ago", intdiv($x, $d));
    if ($x < 2*$m) return sprintf("%d weeks ago", intdiv($x, $w));
    if ($x < 2*$y) return sprintf("%d months ago", intdiv($x, $m));
    return sprintf("%s years ago", intdiv($x, $y));
}

// divide a list into $ncols parts
//
function split_list($items, $ncols) {
    $n = count($items);
    $x = [];
    for ($i=0; $i<$ncols; $i++) {
        $a = ceil($n*$i/$ncols);
        $b = ceil($n*($i+1)/$ncols);
        $x[] = array_slice($items, $a, ($b-$a));
    }
    return $x;
}

// Display lots of checkboxes divided into columns.
// Returns text for a table with $ncols columns.
// for each item in $items:
// - if it's an array, it's a list of checkbox items; divide it into columns
// - otherwise show it in a row that spans all cols
// Use this as arg to form_general();
//
function checkbox_table($items, $ncols) {
    $x = '<table width=100%>';
    foreach ($items as $item) {
        if (is_array($item)) {
            if (count($item)) {
                $x .= checkbox_table_array($item, $ncols);
            }
        } else {
            $x .= sprintf('<tr colspan=%d><td>%s</td></tr>', $ncols, $item);
        }
    }
    $x .= "</table>\n";
    return $x;
}

// Helper function for the above.
// Return '<tr><td>x</td> ... <td>x</td></tr>'
// where each table cell contains 1/ncols of the given checkbox items
//
function checkbox_table_array($items, $ncols) {
    $x = '<tr>';
    $y = split_list($items, $ncols);
    for ($i=0; $i<$ncols; $i++) {
        $x .= sprintf("<td valign=top style=\"padding: 4px\" width=\"%d%%\">%s</td>\n",
            intdiv(100, $ncols),
            implode('<br>', checkbox_item_strings($y[$i]))
        );
    }
    $x .= '</tr>';
    return $x;
}

// Not used - delete?
//
function checkbox_array($items, $ncols, $last=null) {
    $y = split_list($items, $ncols);
    $x = '<table width=100%><tr>';
    for ($i=0; $i<$ncols; $i++) {
        $x .= sprintf("<td valign=top style=\"padding: 4px\" width=\"%d%%\">%s</td>\n",
            intdiv(100, $ncols),
            implode('<br>', checkbox_item_strings($y[$i]))
        );
    }
    $x .= '</tr>';
    if ($last) {
        $x .= sprintf('<tr colspan=%d><td>%s</td></tr>', $ncols, $last);
    }
    $x .= "</table>\n";
    return $x;
}

// user name, with link to user page and optional hover for description
//
function user_name_link($user, $profile) {
    return sprintf('<a %s href=user.php?user_id=%d>%s</a>',
        $profile->description?sprintf('title="%s"', $profile->description):'',
        $user->id, $user->name
    );
}

// user pictures.
// users can change pictures, so we need to timestamp them;
// otherwise browser caching will show the old image.
// Call the file ID_timestamp.jpg, and store this name in user.venue
//
//
function picture_path($user) {
    return sprintf("pictures/%s", $user->venue);
}

function has_picture($user) {
    return strlen($user->venue)>0 && file_exists(picture_path($user));
}

?>