using System;
using System.Net.Http;
using System.Threading;
using System.Threading.Tasks;

namespace ReC.Client.Api
{
    /// <summary>
    /// Provides shared CRUD operations for API resources.
    /// </summary>
    public abstract class BaseCrudApi
    {
        /// <summary>
        /// The HTTP client used to send requests.
        /// </summary>
        protected readonly HttpClient Http;

        /// <summary>
        /// The base resource path for the API endpoint.
        /// </summary>
        protected readonly string ResourcePath;

        /// <summary>
        /// Initializes a new instance of the <see cref="BaseCrudApi"/> class.
        /// </summary>
        /// <param name="http">The HTTP client used for requests.</param>
        /// <param name="resourcePath">The base resource path for the API endpoint.</param>
        protected BaseCrudApi(HttpClient http, string resourcePath)
        {
            Http = http ?? throw new ArgumentNullException(nameof(http));
            ResourcePath = resourcePath ?? throw new ArgumentNullException(nameof(resourcePath));
        }

        /// <summary>
        /// Creates a resource.
        /// </summary>
        /// <typeparam name="T">The payload type.</typeparam>
        /// <param name="payload">The payload to send.</param>
        /// <param name="cancel">A token to cancel the operation.</param>
        /// <returns>The HTTP response message.</returns>
        public Task<HttpResponseMessage> CreateAsync<T>(T payload, CancellationToken cancel = default)
            => Http.PostAsync(ResourcePath, ReCClientHelpers.ToJsonContent(payload), cancel);

        /// <summary>
        /// Updates a resource by identifier.
        /// </summary>
        /// <typeparam name="T">The payload type.</typeparam>
        /// <param name="id">The resource identifier.</param>
        /// <param name="payload">The payload to send.</param>
        /// <param name="cancel">A token to cancel the operation.</param>
        /// <returns>The HTTP response message.</returns>
        public Task<HttpResponseMessage> UpdateAsync<T>(long id, T payload, CancellationToken cancel = default)
            => Http.PutAsync($"{ResourcePath}/{id}", ReCClientHelpers.ToJsonContent(payload), cancel);

        /// <summary>
        /// Deletes resources with identifiers supplied in the payload.
        /// </summary>
        /// <typeparam name="T">The payload type containing identifiers.</typeparam>
        /// <param name="payload">The payload to send.</param>
        /// <param name="cancel">A token to cancel the operation.</param>
        /// <returns>The HTTP response message.</returns>
        public Task<HttpResponseMessage> DeleteAsync<T>(T payload, CancellationToken cancel = default)
        {
            var request = new HttpRequestMessage(HttpMethod.Delete, ResourcePath)
            {
                Content = ReCClientHelpers.ToJsonContent(payload)
            };
            return Http.SendAsync(request, cancel);
        }
    }
}