<?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()) {
    die(json_encode(['success' => false, 'message' => 'Unauthorized']));
}

if ($_SERVER['REQUEST_METHOD'] !== 'POST') {
    die(json_encode(['success' => false, 'message' => 'Invalid request method']));
}

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

if (!$project_id) {
    die(json_encode(['success' => false, 'message' => 'Invalid project ID']));
}

// Verify user has access to this project
$stmt = $db->prepare("SELECT id FROM projects WHERE id = ? AND created_by = ?");
$stmt->bind_param('ii', $project_id, $_SESSION['user_id']);
$stmt->execute();
if ($stmt->get_result()->num_rows === 0) {
    die(json_encode(['success' => false, 'message' => 'Access denied']));
}

// Get all previously used panelist IDs in this project's selections
$stmt = $db->prepare("
    SELECT DISTINCT panelist_id 
    FROM selection_members sm
    JOIN selections s ON sm.selection_id = s.id
    WHERE s.project_id = ?
");
$stmt->bind_param('i', $project_id);
$stmt->execute();
$used_panelists_result = $stmt->get_result();
$used_panelists = [];
while ($row = $used_panelists_result->fetch_assoc()) {
    $used_panelists[] = $row['panelist_id'];
}

// Build WHERE clause based on filter criteria
$where_conditions = [];

// If we have used panelists, exclude them
if (!empty($used_panelists)) {
    $used_panelists_str = "'" . implode("','", $used_panelists) . "'";
    $where_conditions[] = "panelist_id NOT IN ($used_panelists_str)";
}

// Process all form inputs
$attributes = $db->query("SELECT id, name, choice_type FROM attributes ORDER BY created_at ASC");
while ($attr = $attributes->fetch_assoc()) {
    $attr_id = $attr['id'];
    
    if ($attr['choice_type'] === 'single') {
        // Single choice attributes
        if (isset($_POST["attr_{$attr_id}"]) && !empty($_POST["attr_{$attr_id}"])) {
            $value = $db->escape($_POST["attr_{$attr_id}"]);
            $where_conditions[] = "JSON_UNQUOTE(JSON_EXTRACT(attribute_values, '$.{$attr_id}')) = '{$value}'";
        }
    } else if ($attr['choice_type'] === 'multiple') {
    // Multiple choice attributes
    if (isset($_POST["attr_{$attr_id}"]) && is_array($_POST["attr_{$attr_id}"]) && !empty($_POST["attr_{$attr_id}"])) {
        $values = array_map(function($value) use ($db) {
            return $db->escape($value);
        }, $_POST["attr_{$attr_id}"]);
        
        $or_conditions = [];
        foreach ($values as $value) {
            // Use JSON_CONTAINS to check if array contains the value
            $or_conditions[] = "JSON_CONTAINS(attribute_values, '\"{$value}\"', '$.{$attr_id}')";
        }
        
        $where_conditions[] = '(' . implode(' OR ', $or_conditions) . ')';
    }
}
}

// For debugging
error_log("Available samples query conditions: " . implode(' AND ', $where_conditions));

// Build the SQL query to get eligible panelists
$sql = "SELECT COUNT(*) as available_samples FROM panel_data";
if (!empty($where_conditions)) {
    $sql .= " WHERE " . implode(' AND ', $where_conditions);
}

error_log("Available samples SQL: " . $sql);

$result = $db->query($sql);
if (!$result) {
    die(json_encode([
        'success' => false, 
        'message' => 'Error calculating available samples: ' . $db->getLastError()
    ]));
}

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

echo json_encode([
    'success' => true,
    'available_samples' => (int)$available_samples
]);