<?php
include('../inc/check_login.php');
require_once('../inc/db.php');

$message = '';
$message_type = '';
$edit_mode = false;
$edit_meeting = null;

// Nur Admins haben Zugriff
if ($_SESSION['role'] !== 'admin') {
    die("Zugriff nur für Admins");
}

// --- Funktion zur gewichteten zufälligen Farbauswahl ---
function get_weighted_random_color($conn)
{
    // 1. Alle Farben abrufen
    $all_colors = [];
    $result_all = mysqli_query($conn, "SELECT id FROM colors");
    while ($row = mysqli_fetch_assoc($result_all)) {
        $all_colors[] = $row['id'];
    }

    if (empty($all_colors)) {
        return null; // Keine Farben vorhanden
    }

    // 2. Anzahl der Farben als "Sperrzeit"
    $color_count = count($all_colors);

    // 3. Kürzlich verwendete Farben abrufen
    $used_colors_id = [];
    $stmt = mysqli_prepare($conn, "SELECT color_id FROM meetings ORDER BY meeting_date DESC LIMIT ?");
    mysqli_stmt_bind_param($stmt, "i", $color_count);
    mysqli_stmt_execute($stmt);
    $result_used = mysqli_stmt_get_result($stmt);
    while ($row = mysqli_fetch_assoc($result_used)) {
        $used_colors_id[] = $row['color_id'];
    }
    mysqli_stmt_close($stmt);

    // 4. Farben-Pool erstellen
    $color_pool = [];
    foreach ($all_colors as $color_id) {
        if (in_array($color_id, $used_colors_id)) {
            // Kürzlich verwendete Farben haben 1x Chance
            $color_pool[] = $color_id;
        } else {
            // Andere Farben haben 3x Chance
            $color_pool[] = $color_id;
            $color_pool[] = $color_id;
            $color_pool[] = $color_id;
        }
    }

    // 5. Zufällige Farbe aus dem Pool auswählen
    shuffle($color_pool);
    return $color_pool[0];
}

// --- Logik zum Löschen und Bearbeiten von Terminen ---

// Aktion Löschen
if (isset($_GET['action']) && $_GET['action'] == 'delete' && isset($_GET['id'])) {
    $id = $_GET['id'];
    $stmt = mysqli_prepare($conn, "DELETE FROM meetings WHERE id = ?");
    mysqli_stmt_bind_param($stmt, "i", $id);
    if (mysqli_stmt_execute($stmt)) {
        $message = "Termin erfolgreich gelöscht!";
        $message_type = 'success';
    } else {
        $message = "Fehler beim Löschen des Termins.";
        $message_type = 'danger';
    }
    mysqli_stmt_close($stmt);
}

// Aktion Bearbeiten (Formular laden)
if (isset($_GET['action']) && $_GET['action'] == 'edit' && isset($_GET['id'])) {
    $id = $_GET['id'];
    $stmt = mysqli_prepare($conn, "SELECT id, meeting_date, color_id FROM meetings WHERE id = ?");
    mysqli_stmt_bind_param($stmt, "i", $id);
    mysqli_stmt_execute($stmt);
    $result = mysqli_stmt_get_result($stmt);
    $edit_meeting = mysqli_fetch_assoc($result);
    mysqli_stmt_close($stmt);
    $edit_mode = true;
}

// --- Logik zum Hinzufügen oder Speichern von Terminen (POST) ---

if ($_SERVER["REQUEST_METHOD"] == "POST") {
    $meeting_date = $_POST['meeting_date'];
    $color_id = $_POST['color_id'];
    $id = $_POST['id'] ?? null;

    if ($id) { // Update-Logik
        $stmt = mysqli_prepare($conn, "UPDATE meetings SET meeting_date = ?, color_id = ? WHERE id = ?");
        mysqli_stmt_bind_param($stmt, "sii", $meeting_date, $color_id, $id);
        if (mysqli_stmt_execute($stmt)) {
            $message = "Termin erfolgreich aktualisiert!";
            $message_type = 'success';
        } else {
            $message = "Fehler beim Aktualisieren des Termins.";
            $message_type = 'danger';
        }
        mysqli_stmt_close($stmt);
    } else { // Insert-Logik
        $stmt = mysqli_prepare($conn, "INSERT INTO meetings (meeting_date, color_id) VALUES (?, ?)");
        mysqli_stmt_bind_param($stmt, "si", $meeting_date, $color_id);
        if (mysqli_stmt_execute($stmt)) {
            $message = "Neuer Termin erfolgreich hinzugefügt!";
            $message_type = 'success';
        } else {
            $message = "Fehler beim Hinzufügen des Termins.";
            $message_type = 'danger';
        }
        mysqli_stmt_close($stmt);
    }
}

// --- Nächste 2 Donnerstage automatisch hinzufügen ---
$date = new DateTime('now');
$date->modify('next thursday');

for ($i = 0; $i < 2; $i++) {
    $next_thursday = $date->format('Y-m-d');

    $stmt = mysqli_prepare($conn, "SELECT id FROM meetings WHERE meeting_date = ?");
    mysqli_stmt_bind_param($stmt, "s", $next_thursday);
    mysqli_stmt_execute($stmt);
    mysqli_stmt_store_result($stmt);

    if (mysqli_stmt_num_rows($stmt) == 0) {
        $color_id = get_weighted_random_color($conn);
        if ($color_id) {
            $stmt_insert = mysqli_prepare($conn, "INSERT INTO meetings (meeting_date, color_id) VALUES (?, ?)");
            mysqli_stmt_bind_param($stmt_insert, "si", $next_thursday, $color_id);
            mysqli_stmt_execute($stmt_insert);
            mysqli_stmt_close($stmt_insert);
        }
    }
    mysqli_stmt_close($stmt);

    $date->modify('+1 week');
}

// --- Termine und alle Farben abrufen (für Übersicht und Formular) ---
$all_colors = [];
$result = mysqli_query($conn, "SELECT id, name, hex_code FROM colors ORDER BY name");
while ($row = mysqli_fetch_assoc($result)) {
    $all_colors[] = $row;
}

$meetings = [];
$result = mysqli_query($conn, "SELECT m.id, m.meeting_date, m.created_at, c.name AS color_name, c.hex_code FROM meetings m JOIN colors c ON m.color_id = c.id ORDER BY m.meeting_date");
while ($row = mysqli_fetch_assoc($result)) {
    $meetings[] = $row;
}

require_once '../inc/header.php';
?>

<div class="container mt-5">
    <h2 class="mb-4">Terminverwaltung</h2>

    <?php if ($message) : ?>
        <div id="status-message" class="alert alert-<?php echo $message_type; ?> alert-dismissible fade show" role="alert">
            <?php echo htmlspecialchars($message); ?>
            <button type="button" class="btn-close" data-bs-dismiss="alert" aria-label="Close"></button>
        </div>
    <?php endif; ?>

    <div class="card shadow mb-4">
        <div class="card-header bg-primary text-white">
            <h4 class="mb-0"><?php echo $edit_mode ? 'Termin bearbeiten' : 'Neuen Termin hinzufügen'; ?></h4>
        </div>
        <div class="card-body">
            <form action="meetings.php" method="post">
                <?php if ($edit_mode): ?>
                    <input type="hidden" name="id" value="<?php echo htmlspecialchars($edit_meeting['id']); ?>">
                <?php endif; ?>
                <div class="row g-1 align-items-end">
                    <div class="col-md-6">
                        <label for="meeting_date" class="form-label">Datum</label>
                        <input type="date" class="form-control" id="meeting_date" name="meeting_date" value="<?php echo htmlspecialchars($edit_meeting['meeting_date'] ?? ''); ?>" required>
                        <div class="form-text" style="visibility: hidden;">&nbsp;</div>
                    </div>
                    <div class="col-md-6">
                        <label for="color_id" class="form-label">Farbe</label>
                        <select class="form-select" id="color_id" name="color_id" required>
                            <?php foreach ($all_colors as $color): ?>
                                <option value="<?php echo htmlspecialchars($color['id']); ?>" <?php echo (($edit_meeting['color_id'] ?? '') == $color['id']) ? 'selected' : ''; ?>>
                                    <?php echo htmlspecialchars($color['name']); ?>
                                </option>
                            <?php endforeach; ?>
                        </select>
                        <div class="form-text" style="visibility: hidden;">&nbsp;</div>
                    </div>
                    <div class="col-12 d-flex justify-content-start">
                        <button type="submit" class="btn btn-<?php echo $edit_mode ? 'success' : 'primary'; ?> w-auto me-2">
                            <?php echo $edit_mode ? 'Speichern' : 'Hinzufügen'; ?>
                        </button>
                        <?php if ($edit_mode): ?>
                            <a href="meetings.php" class="btn btn-secondary w-auto">Abbrechen</a>
                        <?php endif; ?>
                    </div>
                </div>
            </form>
        </div>
    </div>

    <div class="card shadow">
        <div class="card-header bg-secondary text-white">
            <h4 class="mb-0">Übersicht der Termine</h4>
        </div>
        <div class="card-body">
            <?php if (empty($meetings)): ?>
                <p class="text-muted text-center">Es sind noch keine Termine vorhanden.</p>
            <?php else: ?>
                <div class="table-responsive">
                    <table class="table table-striped table-hover">
                        <thead>
                            <tr>
                                <th>Datum</th>
                                <th>Farbe</th>
                                <th>Aktionen</th>
                            </tr>
                        </thead>
                        <tbody>
                            <?php foreach ($meetings as $meeting): ?>
                                <tr>
                                    <td><?php echo date('d.m.Y', strtotime($meeting['meeting_date'])); ?></td>
                                    <td>
                                        <div class="d-flex align-items-center">
                                            <div class="color-preview rounded me-2" style="background-color: <?php echo htmlspecialchars($meeting['hex_code']); ?>;"></div>
                                            <span><?php echo htmlspecialchars($meeting['color_name']); ?></span>
                                        </div>
                                    </td>
                                    <td>
                                        <a href="meetings.php?action=edit&id=<?php echo htmlspecialchars($meeting['id']); ?>" class="text-dark me-1 text-decoration-none" data-bs-toggle="tooltip" data-bs-placement="top" title="Bearbeiten">
                                            <span class="material-icons">mode_edit_outline</span>
                                        </a>
                                        <a href="meetings.php?action=delete&id=<?php echo htmlspecialchars($meeting['id']); ?>" class="text-danger text-decoration-none" onclick="return confirm('Sind Sie sicher, dass Sie diesen Termin löschen möchten?');" data-bs-toggle="tooltip" data-bs-placement="top" title="Löschen">
                                            <span class="material-icons">delete_outline</span>
                                        </a>
                                    </td>
                                </tr>
                            <?php endforeach; ?>
                        </tbody>
                    </table>
                </div>
            <?php endif; ?>
        </div>
    </div>
</div>

<?php include('../inc/footer.php'); ?>