<?php
/**
 * Delete Survey URLs
 * Allows clients to delete unsent survey URLs from a batch
 */

require_once 'client-session.php';
requireClientLogin();

// Set JSON response header
header('Content-Type: application/json');

$client_id = $_SESSION['client_id'];

try {
    // Get JSON input
    $input = json_decode(file_get_contents('php://input'), true);
    
    if (json_last_error() !== JSON_ERROR_NONE) {
        throw new Exception('Invalid JSON input');
    }
    
    // Validate input
    $project_id = $input['project_id'] ?? '';
    $batch_number = (int)($input['batch_number'] ?? 0);
    $url_ids = $input['url_ids'] ?? [];
    
    if (empty($project_id)) {
        throw new Exception('Project ID is required');
    }
    
    if ($batch_number < 1) {
        throw new Exception('Invalid batch number');
    }
    
    if (empty($url_ids) || !is_array($url_ids)) {
        throw new Exception('No URLs selected for deletion');
    }
    
    // Sanitize URL IDs (ensure they're all integers)
    $url_ids = array_map('intval', $url_ids);
    $url_ids = array_filter($url_ids, function($id) { return $id > 0; });
    
    if (empty($url_ids)) {
        throw new Exception('Invalid URL IDs');
    }
    
    // Get database connection
    $pdo = getClientDBConnection();
    
    // Verify project belongs to client
    $stmt = $pdo->prepare("
        SELECT project_id, project_name 
        FROM projects 
        WHERE project_id = ? AND client_id = ?
    ");
    $stmt->execute([$project_id, $client_id]);
    $project = $stmt->fetch();
    
    if (!$project) {
        throw new Exception('Project not found or access denied');
    }
    
    // Start transaction
    $pdo->beginTransaction();
    
    try {
        // Delete only unsent URLs that belong to this project and batch
        $placeholders = str_repeat('?,', count($url_ids) - 1) . '?';
        
        $stmt = $pdo->prepare("
            DELETE FROM survey_urls 
            WHERE id IN ($placeholders)
            AND project_id = ?
            AND batch_number = ?
            AND is_sent = 0
        ");
        
        $params = array_merge($url_ids, [$project_id, $batch_number]);
        $stmt->execute($params);
        
        $deleted_count = $stmt->rowCount();
        
        if ($deleted_count === 0) {
            throw new Exception('No URLs were deleted. They may have already been sent or do not exist.');
        }
        
        // Update batch totals
        $stmt = $pdo->prepare("
            UPDATE survey_url_batches 
            SET total_urls = total_urls - ?
            WHERE project_id = ? 
            AND batch_number = ?
        ");
        $stmt->execute([$deleted_count, $project_id, $batch_number]);
        
        // Check if batch is now empty and delete it if so
        $stmt = $pdo->prepare("
            SELECT total_urls FROM survey_url_batches 
            WHERE project_id = ? AND batch_number = ?
        ");
        $stmt->execute([$project_id, $batch_number]);
        $batch = $stmt->fetch();
        
        if ($batch && $batch['total_urls'] <= 0) {
            // Delete empty batch
            $stmt = $pdo->prepare("
                DELETE FROM survey_url_batches 
                WHERE project_id = ? AND batch_number = ?
            ");
            $stmt->execute([$project_id, $batch_number]);
        }
        
        // Commit transaction
        $pdo->commit();
        
        // Log activity
        error_log(sprintf(
            "Client %d deleted %d URLs from project %s batch %d",
            $client_id,
            $deleted_count,
            $project_id,
            $batch_number
        ));
        
        echo json_encode([
            'success' => true,
            'deleted' => $deleted_count,
            'message' => "Successfully deleted $deleted_count URL" . ($deleted_count > 1 ? 's' : '')
        ]);
        
    } catch (Exception $e) {
        // Rollback on error
        $pdo->rollBack();
        throw $e;
    }
    
} catch (Exception $e) {
    error_log("Delete URLs Error: " . $e->getMessage());
    
    echo json_encode([
        'success' => false,
        'message' => $e->getMessage()
    ]);
}
?>