<?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 POST data for filters
$filters = isset($_POST['filters']) ? json_decode($_POST['filters'], true) : [];

// 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 filter criteria from attributes
if (!empty($filters)) {
    // Get attribute types
    $attr_types = [];
    $attr_query = $db->query("SELECT id, choice_type FROM attributes");
    while ($attr = $attr_query->fetch_assoc()) {
        $attr_types[$attr['id']] = $attr['choice_type'];
    }
    
    foreach ($filters as $attr_id => $value) {
        if (!empty($value)) {
            // Skip attr_ prefix in keys if present
            $attr_id = str_replace('attr_', '', $attr_id);
            
            $choice_type = $attr_types[$attr_id] ?? 'single';
            
            if ($choice_type === 'single') {
                // Single choice attributes
                $value = $db->escape($value);
                $where_conditions[] = "JSON_UNQUOTE(JSON_EXTRACT(attribute_values, '$.{$attr_id}')) = '{$value}'";
            } else if ($choice_type === 'multiple' && is_array($value) && !empty($value)) {
                // Multiple choice attributes
                $or_conditions = [];
                foreach ($value as $v) {
                    $escaped_value = $db->escape($v);
                    // Use JSON_CONTAINS to check if array contains the value
                    $or_conditions[] = "JSON_CONTAINS(attribute_values, '\"{$escaped_value}\"', '$.{$attr_id}')";
                }
                
                if (!empty($or_conditions)) {
                    $where_conditions[] = '(' . implode(' OR ', $or_conditions) . ')';
                }
            }
        }
    }
}

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

// For debugging
error_log("Available count SQL: " . $sql);

// Get the count
$result = $db->query($sql);
if (!$result) {
    die(json_encode(['success' => false, 'message' => 'Error querying panel data: ' . $db->getLastError()]));
}

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

// Return the count
echo json_encode([
    'success' => true,
    'count' => (int)$available_count
]);
?>