using RestSharp;
using System.Text;
using System;
using System.Threading.Tasks;
using Adrenak.Unex;
using UnityEngine;

namespace Adrenak.UniMap {
	/// <summary>
	/// Used to get the coordinates of an address
	/// </summary>
	public class GeocodingRequest {
		const string k_BaseURL = "https://maps.googleapis.com/maps/api/geocode/json?";
		/// <summary>
		/// The Google Maps API key
		/// </summary>
		public string Key { get; private set; }

		/// <summary>
		/// The address to request
		/// </summary>
		public string Address { get; private set; }

		/// <summary>
		/// Language of the request
		/// </summary>
		public string Language { get; set; }

		/// <summary>
		/// ISO code of the region
		/// </summary>
		public string Region { get; set; }

		/// <summary>
		/// Creates an instance for geocoding request
		/// </summary>
		/// <param name="key">The Google Maps API key to be used</param>
		public GeocodingRequest(string key) {
			Key = key;
		}

		/// <summary>
		/// Gets the request URL for the set parameters
		/// </summary>
		public string GetURL() {
			if (Key.IsNullOrEmpty()) 
				throw new Exception("No key provided");

			if (Address.IsNullOrEmpty())
				throw new Exception("No address provided");

			var builder = new StringBuilder(k_BaseURL);
			builder.Append("key=").Append(Key);
			builder.Append("&address=").Append(Address);

			if (!Language.IsNullOrEmpty())
				builder.Append("&language=").Append(Language);

			if (!Region.IsNullOrEmpty())
				builder.Append("&region=").Append(Region);

			return builder.ToString();
		}

        /// <summary>
        /// Sends the request for a given address
        /// </summary>
        /// <param name="address">The address that needs to be geocoded</param>
        /// <param name="onSuccess">Callback on successful request</param>
        /// <param name="onFailure">Callback on unsuccessul request</param>
        public void Send(string address, Action<GeocodingResponse> onSuccess, Action<Exception> onFailure) {
			Address = address;
			var client = new RestClient();
			var request = new RestRequest(GetURL(), Method.GET);

			client.ExecuteAsync(request, response => {
				Dispatcher.Enqueue(() => {
				    if (response.IsSuccessful()) {
						var model = JsonUtility.FromJson<GeocodingResponse>(response.Content);
					
						if (model != null)
							onSuccess?.Invoke(model);
						else {
							var exception = new Exception("Could not deserialize", response.GetException());
							onFailure?.Invoke(exception);
						}
				    }
				    else {
					    var exception = new Exception("Unsuccessful response for Geocoding", response.GetException());
						onFailure?.Invoke(exception);
				    }
				});
			});
		}

        /// <summary>
        /// Sends the request for a given address and returns a task for the response
        /// </summary>
        /// <param name="address">The address that needs to be goecoded</param>
        /// <returns>The promise for the response</returns>
        public Task<GeocodingResponse> Send(string address) {
            var source = new TaskCompletionSource<GeocodingResponse>();
            Send(
                address,
                response => source.SetResult(response),
                exception => source.SetException(exception)
            );
            return source.Task;
        }
	}
}