<?php
require_once '../include/init.php';
require_once '../include/auth.php';

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

// --- Security Check: Only Admin can access this page ---
if (!isAdmin()) {
    http_response_code(403); // Forbidden
    echo json_encode(['success' => false, 'message' => 'You do not have permission to perform this action.']);
    exit;
}

try {
    $messages = [];
    
    // --- Check columns in 'tabs' table ---
    $tabs_columns = $pdo->query("PRAGMA table_info(tabs)")->fetchAll(PDO::FETCH_COLUMN, 1);
    
    $required_columns = [
        'background_image_url' => 'TEXT DEFAULT NULL',
        'background_brightness' => 'INTEGER DEFAULT 100',
        'background_saturation' => 'INTEGER DEFAULT 100',
        'theme' => 'TEXT DEFAULT NULL',
        'theme_transparency' => 'INTEGER DEFAULT NULL',
        'login_token' => 'VARCHAR(255)'
    ];
    
    $columns_added = false;
    foreach ($required_columns as $column_name => $column_definition) {
        if (!in_array($column_name, $tabs_columns)) {
            $pdo->exec("ALTER TABLE tabs ADD COLUMN $column_name $column_definition");
            $messages[] = "Column '$column_name' added to 'tabs' table.";
            $columns_added = true;
        } else {
            $messages[] = "Column '$column_name' already exists in 'tabs' table.";
        }
    }

    // Check for login_token column and add unique index if not present
    $current_tabs_columns = $pdo->query("PRAGMA table_info(tabs)")->fetchAll(PDO::FETCH_COLUMN, 1);
    if (in_array('login_token', $current_tabs_columns)) {
        $indexes = $pdo->query("PRAGMA index_list(tabs)")->fetchAll();
        $index_exists = false;
        foreach ($indexes as $index) {
            // Check if the index is on the login_token column
            $index_info = $pdo->query("PRAGMA index_info({$index['name']})")->fetchAll();
            foreach ($index_info as $info) {
                if ($info['name'] === 'login_token' && $index['unique']) {
                    $index_exists = true;
                    break 2;
                }
            }
        }

        if (!$index_exists) {
            $tabs_without_token = $pdo->query("SELECT id FROM tabs WHERE login_token IS NULL OR login_token = ''")->fetchAll(PDO::FETCH_COLUMN);
            if (!empty($tabs_without_token)) {
                $update_stmt = $pdo->prepare("UPDATE tabs SET login_token = ? WHERE id = ?");
                foreach ($tabs_without_token as $tab_id) {
                    $token = bin2hex(random_bytes(16));
                    $update_stmt->execute([$token, $tab_id]);
                }
                $messages[] = count($tabs_without_token) . " existing tabs updated with a unique login token.";
                $columns_added = true;
            }
            
            try {
                $pdo->exec("CREATE UNIQUE INDEX IF NOT EXISTS idx_tabs_login_token ON tabs(login_token)");
                $messages[] = "Added unique index to login_token column.";
                $columns_added = true;
            } catch (PDOException $e) {
                $messages[] = "Could not create unique index on login_token: " . $e->getMessage();
            }
        } else {
            $messages[] = "Unique index on login_token already exists.";
        }
    }

    if ($columns_added) {
        echo json_encode(['success' => true, 'message' => 'Database updated successfully!', 'details' => $messages]);
    } else {
        echo json_encode(['success' => true, 'message' => 'Database is already up to date.', 'details' => $messages]);
    }

} catch (PDOException $e) {
    http_response_code(500); // Internal Server Error
    echo json_encode(['success' => false, 'message' => 'Database error: ' . $e->getMessage()]);
}