<?php
require_once 'includes/config.php';
require_once 'includes/functions.php';
require_once 'includes/auth.php';
require_once 'includes/db.php';

$auth = new Auth();

// Check if user is logged in
if (!$auth->isLoggedIn()) {
    $_SESSION['error_message'] = 'Unauthorized';
    redirectTo('projects.php');
    exit;
}

if ($_SERVER['REQUEST_METHOD'] !== 'POST') {
    $_SESSION['error_message'] = 'Invalid request method';
    redirectTo('projects.php');
    exit;
}

$db = Database::getInstance();
$selection_id = isset($_POST['selection_id']) ? (int)$_POST['selection_id'] : 0;
$project_id = isset($_POST['project_id']) ? (int)$_POST['project_id'] : 0;

if (!$selection_id || !$project_id) {
    $_SESSION['error_message'] = 'Required fields are missing';
    redirectTo("manage_project.php?id=$project_id");
    exit;
}

// Verify user has access to this selection and project
$stmt = $db->prepare("
    SELECT s.name 
    FROM selections s
    JOIN projects p ON s.project_id = p.id
    WHERE s.id = ? AND p.id = ? AND p.created_by = ?
");
$stmt->bind_param('iii', $selection_id, $project_id, $_SESSION['user_id']);
$stmt->execute();
$result = $stmt->get_result();

if ($result->num_rows === 0) {
    $_SESSION['error_message'] = 'Selection not found or access denied';
    redirectTo("manage_project.php?id=$project_id");
    exit;
}

$selection_name = $result->fetch_assoc()['name'];

// Begin transaction
$db->query("START TRANSACTION");

try {
    // First delete selection members
    $stmt = $db->prepare("DELETE FROM selection_members WHERE selection_id = ?");
    $stmt->bind_param('i', $selection_id);
    
    if (!$stmt->execute()) {
        throw new Exception("Failed to delete selection members: " . $db->getLastError());
    }
    
    // Then delete the selection
    $stmt = $db->prepare("DELETE FROM selections WHERE id = ?");
    $stmt->bind_param('i', $selection_id);
    
    if (!$stmt->execute()) {
        throw new Exception("Failed to delete selection: " . $db->getLastError());
    }
    
    // Commit the transaction
    $db->query("COMMIT");
    
    $_SESSION['success_message'] = "Selection '$selection_name' has been deleted successfully";
    redirectTo("manage_project.php?id=$project_id");
    
} catch (Exception $e) {
    // Rollback on error
    $db->query("ROLLBACK");
    $_SESSION['error_message'] = $e->getMessage();
    redirectTo("manage_project.php?id=$project_id");
}
?>