using System.Threading.Tasks;
using System.Text.Json;
using Microsoft.JSInterop;

namespace MP.Data.Services
{
    public interface ISessionStorageService
    {
        #region Public Methods

        Task ClearAsync();
        Task<bool> ContainKeyAsync(string key);
        Task<T?> GetItemAsync<T>(string key);
        Task<T> GetItemAsync<T>(string key, T fallback);
        Task RemoveItemAsync(string key);
        Task SetItemAsync<T>(string key, T value);

        #endregion Public Methods
    }

    public class SessionStorageService : ISessionStorageService
    {
        #region Public Constructors

        public SessionStorageService(IJSRuntime js)
        {
            _js = js;
        }

        #endregion Public Constructors

        #region Public Methods

        public async Task ClearAsync()
        {
            await _js.InvokeVoidAsync("sessionStorage.clear");
        }

        public async Task<bool> ContainKeyAsync(string key)
        {
            var value = await _js.InvokeAsync<string>("sessionStorage.getItem", key);
            return value != null;
        }

        /// <summary>
        /// Lettura con valori default(null) in caso di missing:
        /// int: 0
        /// string: null
        /// bool: false
        /// DateTime: 01/01/0001
        /// myClass: null
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="key"></param>
        /// <returns></returns>
        public async Task<T?> GetItemAsync<T>(string key)
        {
            var json = await _js.InvokeAsync<string>("sessionStorage.getItem", key);

            if (json is null)
                return default;

            return JsonSerializer.Deserialize<T>(json);
        }

        /// <summary>
        /// Lettura valore con gestione fallback esplicito
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="key"></param>
        /// <param name="fallback"></param>
        /// <returns></returns>
        public async Task<T> GetItemAsync<T>(string key, T fallback)
        {
            var json = await _js.InvokeAsync<string>("sessionStorage.getItem", key);

            if (json is null)
                return fallback;

            return JsonSerializer.Deserialize<T>(json) ?? fallback;
        }

        public async Task RemoveItemAsync(string key)
        {
            await _js.InvokeVoidAsync("sessionStorage.removeItem", key);
        }

        public async Task SetItemAsync<T>(string key, T value)
        {
            var json = JsonSerializer.Serialize(value);
            await _js.InvokeVoidAsync("sessionStorage.setItem", key, json);
        }

        #endregion Public Methods

        #region Private Fields

        private readonly IJSRuntime _js;

        #endregion Private Fields
    }
}