using System;
using System.Globalization;
using System.Linq;
using System.Net.Http.Json;

#if NETFRAMEWORK
using System.Net.Http;
#endif

namespace ReC.Client
{
    /// <summary>
    /// Provides shared helpers for composing requests.
    /// </summary>
    internal static class ReCClientHelpers
    {
#if NETFRAMEWORK
        /// <summary>
        /// Builds a query string from the provided key/value pairs, skipping null values.
        /// </summary>
        /// <param name="parameters">The key/value pairs to include in the query string.</param>
        /// <returns>A query string beginning with '?', or an empty string if no values are provided.</returns>
        public static string BuildQuery(params (string Key, object Value)[] parameters)
#else
        /// <summary>
        /// Builds a query string from the provided key/value pairs, skipping null values.
        /// </summary>
        /// <param name="parameters">The key/value pairs to include in the query string.</param>
        /// <returns>A query string beginning with '?', or an empty string if no values are provided.</returns>
        public static string BuildQuery(params (string Key, object? Value)[] parameters)
#endif
        {
            var parts = parameters
                .Where(p => p.Value != null)
                .Select(p => $"{Uri.EscapeDataString(p.Key)}={Uri.EscapeDataString(Convert.ToString(p.Value, CultureInfo.InvariantCulture) ?? string.Empty)}");

            var query = string.Join("&", parts);
            return string.IsNullOrWhiteSpace(query) ? string.Empty : $"?{query}";
        }

        /// <summary>
        /// Creates a JSON content payload from the provided object.
        /// </summary>
        /// <typeparam name="T">The type of the payload.</typeparam>
        /// <param name="payload">The payload to serialize.</param>
        /// <returns>A <see cref="JsonContent"/> instance ready for HTTP requests.</returns>
        public static JsonContent ToJsonContent<T>(T payload) => JsonContent.Create(payload);
    }
}