<?php
require_once __DIR__ . '/config.php';
require_once __DIR__ . '/db.php';
require_once __DIR__ . '/helpers.php';

$db = get_db();

/* ---------------------------------------------------------------
   Series filter for the seminar selector
--------------------------------------------------------------- */
$series_list = all_series($db);
$default_sid = default_series_id($db);

// Default to first series on first visit; 0 = All
if (isset($_GET['series'])) {
    $filter_series = (int)$_GET['series'];
} elseif (!isset($_GET['id'])) {
    $filter_series = $default_sid;
} else {
    $filter_series = 0;
}

/* ---------------------------------------------------------------
   Load open seminars (deadline not yet passed, not finalized)
--------------------------------------------------------------- */
$all_open = $db->query(
    "SELECT * FROM seminars WHERE is_finalized=0 AND visible=1 ORDER BY seminar_date ASC"
)->fetchAll();

$open_seminars = array();
foreach ($all_open as $s) {
    if (!deadline_passed($s['signup_deadline'])) {
        $open_seminars[] = $s;
    }
}

// Apply series filter to the selector list (not to a directly-linked seminar)
$open_seminars_filtered = array();
foreach ($open_seminars as $s) {
    if ($filter_series === 0 || (int)$s['series_id'] === $filter_series) {
        $open_seminars_filtered[] = $s;
    }
}

$seminar_id = isset($_GET['id']) ? (int)$_GET['id'] : 0;
if (!$seminar_id && count($open_seminars) === 1) {
    $seminar_id = (int)$open_seminars[0]['id'];
}

$seminar = null;
$slots   = array();

if ($seminar_id) {
    $st = $db->prepare("SELECT * FROM seminars WHERE id=?");
    $st->execute(array($seminar_id));
    $seminar = $st->fetch();
}

if ($seminar) {
    $st = $db->prepare(
        "SELECT * FROM slots WHERE seminar_id=? AND slot_category IN ('individual','group')
         ORDER BY sort_order ASC, id ASC"
    );
    $st->execute(array($seminar_id));
    $slots = $st->fetchAll();
}

/* ---------------------------------------------------------------
   Pre-load an existing signup when ?uid= is in the URL.
   This populates the form fields and slot buttons.
--------------------------------------------------------------- */
$prefill = array(
    'university_id' => '',
    'person_name'   => '',
    'office_number' => '',
);
$prefill_prefs  = array(); // slot_id => preference (1 or 2)
$existing_id    = null;    // signups.id of the record being edited
$loaded_uid     = false;   // true when we successfully loaded an existing signup

if ($seminar && isset($_GET['uid']) && trim($_GET['uid']) !== '') {
    $uid = trim($_GET['uid']);
    $st  = $db->prepare(
        "SELECT * FROM signups WHERE seminar_id=? AND LOWER(university_id)=LOWER(?)"
    );
    $st->execute(array($seminar_id, $uid));
    $existing = $st->fetch();

    if ($existing) {
        $existing_id              = $existing['id'];
        $prefill['university_id'] = $existing['university_id'];
        $prefill['person_name']   = $existing['person_name'];
        $prefill['office_number'] = $existing['office_number'];
        $loaded_uid               = true;

        $pst = $db->prepare(
            "SELECT slot_id, preference FROM slot_preferences WHERE signup_id=?"
        );
        $pst->execute(array($existing_id));
        foreach ($pst->fetchAll() as $p) {
            $prefill_prefs[$p['slot_id']] = (int)$p['preference'];
        }
    }
}

/* ---------------------------------------------------------------
   Handle POST submission
--------------------------------------------------------------- */
$errors = array();

if ($_SERVER['REQUEST_METHOD'] === 'POST' && $seminar) {
    $university_id = trim(isset($_POST['university_id']) ? $_POST['university_id'] : '');
    $person_name   = trim(isset($_POST['person_name'])   ? $_POST['person_name']   : '');
    $office_number = trim(isset($_POST['office_number']) ? $_POST['office_number'] : '');
    $prefs         = isset($_POST['prefs']) && is_array($_POST['prefs']) ? $_POST['prefs'] : array();

    if ($university_id === '') $errors[] = 'Please enter your university ID (e.g., healy.52).';
    if ($person_name   === '') $errors[] = 'Please enter your full name.';
    if ($office_number === '') $errors[] = 'Please enter your office number.';

    if (deadline_passed($seminar['signup_deadline'])) {
        $errors[] = 'The signup deadline has passed.';
    }

    if (empty($errors)) {
        // Look up by university_id first; fall back to name for legacy records
        $chk = $db->prepare(
            "SELECT id FROM signups WHERE seminar_id=? AND LOWER(university_id)=LOWER(?)"
        );
        $chk->execute(array($seminar_id, $university_id));
        $existing = $chk->fetch();

        if ($existing) {
            $signup_id = $existing['id'];
            $db->prepare(
                "UPDATE signups SET person_name=?, office_number=?, university_id=? WHERE id=?"
            )->execute(array($person_name, $office_number, $university_id, $signup_id));
            $db->prepare("DELETE FROM slot_preferences WHERE signup_id=?")
               ->execute(array($signup_id));
        } else {
            $db->prepare(
                "INSERT INTO signups (seminar_id, university_id, person_name, office_number)
                 VALUES (?, ?, ?, ?)"
            )->execute(array($seminar_id, $university_id, $person_name, $office_number));
            $signup_id = $db->lastInsertId();
        }

        // Save slot preferences
        $ins = $db->prepare(
            "INSERT OR REPLACE INTO slot_preferences (signup_id, slot_id, preference)
             VALUES (?, ?, ?)"
        );
        foreach ($prefs as $slot_id_raw => $pref_val) {
            $slot_id_clean = (int)$slot_id_raw;
            $pref_clean    = ((int)$pref_val === 2) ? 2 : 1;
            if ($slot_id_clean > 0 && (int)$pref_val > 0) {
                $ins->execute(array($signup_id, $slot_id_clean, $pref_clean));
            }
        }

        redirect(
            '/seminars/signup.php?id=' . $seminar_id
            . '&done=1&uid=' . urlencode($university_id)
        );
    }

    // On error, re-populate fields from POST
    $prefill['university_id'] = $university_id;
    $prefill['person_name']   = $person_name;
    $prefill['office_number'] = $office_number;
    // Slot states come from $_POST['prefs'] directly in the template
}

/* ---------------------------------------------------------------
   Confirmation: load saved preferences to display
--------------------------------------------------------------- */
$done_signup = null;
$done_prefs  = array();

if (isset($_GET['done']) && isset($_GET['uid']) && $seminar) {
    $uid = trim($_GET['uid']);
    $st  = $db->prepare(
        "SELECT * FROM signups WHERE seminar_id=? AND LOWER(university_id)=LOWER(?)"
    );
    $st->execute(array($seminar_id, $uid));
    $done_signup = $st->fetch();

    if ($done_signup) {
        $pst = $db->prepare(
            "SELECT slot_id, preference FROM slot_preferences WHERE signup_id=?"
        );
        $pst->execute(array($done_signup['id']));
        foreach ($pst->fetchAll() as $p) {
            $done_prefs[$p['slot_id']] = (int)$p['preference'];
        }
    }
}

/* ---------------------------------------------------------------
   Page output
--------------------------------------------------------------- */
page_start('Sign Up for a Visit');
page_heading('Sign Up for a Speaker Visit');
?>

<?php /* ===== CONFIRMATION ===== */ ?>
<?php if (isset($_GET['done']) && $seminar && $done_signup): ?>

  <div class="alert alert-success">
    <strong>Thanks, <?php echo h($done_signup['person_name']); ?>!</strong>
    Your availability has been saved for
    <strong><?php echo h($seminar['speaker_name']); ?></strong>&rsquo;s visit
    on <?php echo h(format_date_long($seminar['seminar_date'])); ?>.
  </div>

  <div class="card">
    <div class="card-title">Your selections</div>
    <?php if (empty($done_prefs)): ?>
      <p class="text-muted">You didn&rsquo;t mark any slots as available.</p>
    <?php else: ?>
    <table class="table">
      <thead><tr><th>Time</th><th>Event</th><th>Your preference</th></tr></thead>
      <tbody>
        <?php foreach ($slots as $slot):
          if (!isset($done_prefs[$slot['id']])) continue;
          $p = $done_prefs[$slot['id']];
        ?>
        <tr>
          <td><?php echo format_time_range($slot['start_time'], $slot['end_time']); ?></td>
          <td><?php echo h($slot['label']); ?></td>
          <td>
            <?php if ($p == 2): ?>
              <span class="badge badge-amber">&#9733; Preferred</span>
            <?php else: ?>
              <span class="badge badge-green">Available</span>
            <?php endif; ?>
          </td>
        </tr>
        <?php endforeach; ?>
      </tbody>
    </table>
    <?php endif; ?>
  </div>

  <!-- Return link -->
  <div class="card" style="background:#f7fafc;">
    <p class="text-sm" style="margin-bottom:8px;">
      <strong>Want to change your availability later?</strong>
      Use this personal link &mdash; bookmark it or keep it handy:
    </p>
    <?php
    $return_url = 'https://' . $_SERVER['HTTP_HOST']
        . '/seminars/signup.php?id=' . $seminar_id
        . '&uid=' . urlencode($done_signup['university_id']);
    ?>
    <div style="background:white;border:1px solid #e2e8f0;border-radius:6px;padding:10px 14px;font-family:monospace;font-size:.85rem;word-break:break-all;">
      <?php echo h($return_url); ?>
    </div>
    <p class="text-xs text-muted mt-2">
      Or just return to the signup page and enter your university ID
      (<strong><?php echo h($done_signup['university_id']); ?></strong>)
      &mdash; your choices will load automatically.
    </p>
  </div>

  <p>
    <a href="<?php echo h('/seminars/signup.php?id=' . $seminar_id . '&uid=' . urlencode($done_signup['university_id'])); ?>"
       class="btn btn-outline">Edit my availability</a>
  </p>

<?php /* ===== NO OPEN SEMINARS ===== */ ?>
<?php elseif (!$seminar && empty($open_seminars)): ?>

  <div class="alert alert-info">
    There are no upcoming speaker visits currently accepting signups.
    Check the <a href="/seminars/calendar.php">calendar</a> for past schedules.
  </div>

<?php /* ===== SEMINAR SELECTOR ===== */ ?>
<?php elseif (!$seminar): ?>

  <!-- Series filter pills -->
  <div style="display:flex;flex-wrap:wrap;gap:8px;margin-bottom:16px;">
    <?php
    $all_url = '/seminars/signup.php?series=0';
    $all_active = ($filter_series === 0);
    ?>
    <a href="<?php echo h($all_url); ?>"
       style="display:inline-block;padding:6px 14px;border-radius:20px;font-size:.85rem;
              text-decoration:none;border:1px solid <?php echo $all_active ? '#3182ce' : '#e2e8f0'; ?>;
              background:<?php echo $all_active ? '#3182ce' : '#fff'; ?>;
              color:<?php echo $all_active ? '#fff' : '#4a5568'; ?>;">
      All series
    </a>
    <?php foreach ($series_list as $sr):
      $sr_active = ($filter_series === (int)$sr['id']);
    ?>
    <a href="/seminars/signup.php?series=<?php echo h($sr['id']); ?>"
       style="display:inline-block;padding:6px 14px;border-radius:20px;font-size:.85rem;
              text-decoration:none;border:1px solid <?php echo $sr_active ? '#3182ce' : '#e2e8f0'; ?>;
              background:<?php echo $sr_active ? '#3182ce' : '#fff'; ?>;
              color:<?php echo $sr_active ? '#fff' : '#4a5568'; ?>;">
      <?php echo h($sr['name']); ?>
    </a>
    <?php endforeach; ?>
  </div>

  <div class="card">
    <div class="card-title">Choose a visit</div>
    <?php if (empty($open_seminars_filtered)): ?>
      <p class="text-muted">No visits currently accepting signups in this series.
        <a href="/seminars/signup.php?series=0">Show all series</a>.
      </p>
    <?php else: ?>
    <div style="display:flex;flex-direction:column;gap:12px;">
      <?php foreach ($open_seminars_filtered as $s): ?>
      <a href="/seminars/signup.php?id=<?php echo h($s['id']); ?>"
         style="display:block;padding:14px 18px;border:1px solid #e2e8f0;border-radius:8px;
                text-decoration:none;background:#fff;transition:background .12s;"
         onmouseover="this.style.background='#ebf8ff'"
         onmouseout="this.style.background='#fff'">
        <div class="font-bold" style="color:#2d3748;"><?php echo h($s['speaker_name']); ?></div>
        <div class="text-sm text-muted"><?php echo h(format_date_long($s['seminar_date'])); ?></div>
        <div class="text-sm text-muted">Signup deadline: <?php echo h(format_deadline($s['signup_deadline'])); ?></div>
      </a>
      <?php endforeach; ?>
    </div>
    <?php endif; ?>
  </div>

<?php /* ===== MAIN SIGNUP FORM ===== */ ?>
<?php else:
  $is_closed = deadline_passed($seminar['signup_deadline']);
?>

  <div class="card">
    <div class="card-title">Visit details</div>
    <div class="grid-2">
      <div>
        <p class="text-sm text-muted mb-1">Speaker</p>
        <p class="font-bold" style="font-size:1.05rem;"><?php echo h($seminar['speaker_name']); ?></p>
      </div>
      <div>
        <p class="text-sm text-muted mb-1">Date</p>
        <p class="font-bold"><?php echo h(format_date_long($seminar['seminar_date'])); ?></p>
      </div>
    </div>
    <p class="text-sm mt-2">
      Signup deadline: <strong><?php echo h(format_deadline($seminar['signup_deadline'])); ?></strong>
      &nbsp;
      <?php echo $is_closed
          ? '<span class="badge badge-red">Closed</span>'
          : '<span class="badge badge-green">Open</span>'; ?>
    </p>
  </div>

  <?php if ($is_closed): ?>
    <div class="alert alert-warning">Signups for this visit have closed.</div>
  <?php else: ?>

  <?php if ($loaded_uid): ?>
    <div class="alert alert-info">
      Loaded your existing signup for <strong><?php echo h($prefill['person_name']); ?></strong>.
      Make any changes below and resubmit.
    </div>
  <?php endif; ?>

  <?php if (!empty($errors)): ?>
    <div class="alert alert-error">
      <?php foreach ($errors as $e): echo '<div>' . h($e) . '</div>'; endforeach; ?>
    </div>
  <?php endif; ?>

  <form method="post" action="/seminars/signup.php?id=<?php echo $seminar_id; ?>">

    <div class="card">
      <div class="card-title">Your information</div>
      <div class="grid-2">

        <div class="form-group">
          <label for="university_id">University ID</label>
          <input type="text" id="university_id" name="university_id"
                 value="<?php echo h($prefill['university_id']); ?>"
                 placeholder="e.g., azrieli.2" required>
          <p class="hint">
            Your OSU name.# ID. Used to retrieve and update your signup later.
          </p>
        </div>

        <div class="form-group">
          <label for="person_name">Full name</label>
          <input type="text" id="person_name" name="person_name"
                 value="<?php echo h($prefill['person_name']); ?>"
                 placeholder="e.g., Yaron Azrieli" required>
        </div>

        <div class="form-group">
          <label for="office_number">Office number</label>
          <input type="text" id="office_number" name="office_number"
                 value="<?php echo h($prefill['office_number']); ?>"
                 placeholder="e.g., 275">
          <p class="hint">PhD students: use the visitor&rsquo;s office (<?php echo h($seminar ? $seminar['visitor_office'] : DEFAULT_VISITOR_OFFICE); ?>).</p>
        </div>

      </div>
    </div>

    <div class="card">
      <div class="card-title">Your availability</div>
      <p class="text-sm text-muted" style="margin-bottom:14px;">
        Click each slot to mark your availability. Click once for
        <strong>Available</strong>, again for <strong>Preferred</strong>,
        again to clear. Slots you leave blank mean you&rsquo;re not available.
      </p>

      <div class="signup-legend">
        <div class="legend-item"><span class="legend-swatch swatch-none"></span> Not available</div>
        <div class="legend-item"><span class="legend-swatch swatch-avail"></span> Available</div>
        <div class="legend-item"><span class="legend-swatch swatch-preferred"></span> &#9733; Preferred</div>
      </div>

      <?php foreach ($slots as $slot):
        // Priority: POST data (on error re-display) > prefill from DB > blank
        if ($_SERVER['REQUEST_METHOD'] === 'POST') {
            $init_state = isset($_POST['prefs'][$slot['id']]) ? (int)$_POST['prefs'][$slot['id']] : 0;
        } else {
            $init_state = isset($prefill_prefs[$slot['id']]) ? $prefill_prefs[$slot['id']] : 0;
        }
      ?>
      <div class="slot-btn"
           id="btn-<?php echo $slot['id']; ?>"
           onclick="cycleSlot(<?php echo $slot['id']; ?>)">
        <input type="hidden"
               name="prefs[<?php echo $slot['id']; ?>]"
               id="pref-<?php echo $slot['id']; ?>"
               value="<?php echo $init_state; ?>">
        <span class="slot-time"><?php echo format_time_range($slot['start_time'], $slot['end_time']); ?></span>
        <span class="slot-label">
          <?php echo h($slot['label']); ?>
          <?php if ($slot['slot_category'] === 'group'): ?>
            <span class="group-slot-note">(group event)</span>
          <?php endif; ?>
        </span>
        <span class="slot-status-txt" id="status-<?php echo $slot['id']; ?>">—</span>
      </div>
      <?php endforeach; ?>
    </div>

    <div class="mt-4">
      <button type="submit" class="btn btn-success" style="font-size:1rem;padding:11px 28px;">
        <?php echo $loaded_uid ? 'Update my availability' : 'Submit my availability'; ?>
      </button>
    </div>

  </form>

  <?php endif; // is_closed ?>
<?php endif; ?>

<script>
var labels  = ['—', 'Available', '★ Preferred'];
var classes = ['', 'state-avail', 'state-preferred'];

document.addEventListener('DOMContentLoaded', function() {
    var btns = document.querySelectorAll('.slot-btn');
    for (var i = 0; i < btns.length; i++) {
        var id    = btns[i].id.replace('btn-', '');
        var state = parseInt(document.getElementById('pref-' + id).value) || 0;
        applyState(id, state);
    }
});

function cycleSlot(id) {
    var input   = document.getElementById('pref-' + id);
    var current = parseInt(input.value) || 0;
    var next    = (current + 1) % 3;
    input.value = next;
    applyState(id, next);
}

function applyState(id, state) {
    var btn = document.getElementById('btn-' + id);
    var txt = document.getElementById('status-' + id);
    btn.className = 'slot-btn' + (state > 0 ? ' ' + classes[state] : '');
    txt.textContent = labels[state];
}
</script>

<?php page_end(); ?>