using System;
using System.Collections.Generic;
using System.Net.Http;
using System.Net.Http.Headers;
using System.Text;
using System.Threading.Tasks;

namespace Ophthalmology.DataAccess.Services
{
    public abstract class GenericService<T> where T : new()
    {
        static string _baseUrl = null;

        public GenericService(string serviceDiscoveryUrl)
        {
            ServiceDiscoveryClient.ServiceDiscoveryClient.ServiceDiscoveryUrl = serviceDiscoveryUrl;
        }

        public async Task Initialize(AuthenticationHeaderValue authorization)
        {
            if (string.IsNullOrEmpty(GetKey()) || string.IsNullOrEmpty(_baseUrl))
                _baseUrl = await ServiceDiscoveryClient.ServiceDiscoveryClient.GetEndpoint(GetKey(), authorization);
        }

        public async Task Initialize(string applicationID, string applicationVersion, string tenantId, string facilityId)
        {
            if (string.IsNullOrEmpty(GetKey()) || string.IsNullOrEmpty(_baseUrl))
                _baseUrl = await ServiceDiscoveryClient.ServiceDiscoveryClient.GetEndpoint(GetKey(), applicationID, applicationVersion, tenantId, facilityId);
        }

        public string GetBaseUrl()
        {
            return _baseUrl;
        }

        public abstract string GetKey();

        public abstract T GetClientClass(string baseUrl, HttpClient httpClient);


        public async Task<T> GetClient(AuthenticationHeaderValue authorization)
        {
            System.Net.Http.HttpClient httpClient = new System.Net.Http.HttpClient();
            if (authorization != null)
            {
                httpClient.DefaultRequestHeaders.Authorization = authorization;
            }

            await Initialize(authorization);

            return GetClientClass(GetBaseUrl(), httpClient);
        }

        public async Task<T> GetClient(string applicationID, string applicationVersion, string tenantId, string facilityId)
        {
            System.Net.Http.HttpClient httpClient = new System.Net.Http.HttpClient();

            await Initialize(applicationID, applicationVersion, tenantId, facilityId);

            return GetClientClass(GetBaseUrl(), httpClient);
        }
    }
}