using System;
using System.Collections.Generic;
using System.IO;
using System.Net;
using System.Net.Http;
using System.Net.Http.Headers;
using System.Net.Mime;
using System.Security.Authentication;
using System.Text;
using System.Threading.Tasks;
using System.Web;
using FarmmapsApi.Models;
using IdentityModel;
using Microsoft.AspNetCore.SignalR.Client;
using Microsoft.Extensions.DependencyInjection;
using Newtonsoft.Json;
using Newtonsoft.Json.Linq;

namespace FarmmapsApi.Services
{
    public class FarmmapsApiService
    {
        private readonly HttpClient _httpClient;
        private readonly OpenIdConnectService _openIdConnectService;
        private readonly Configuration _configuration;
        
        private HubConnection _hubConnection;

        public event Action<EventMessage> EventCallback;

        public FarmmapsApiService(HttpClient httpClient,
            OpenIdConnectService openIdConnectService, Configuration configuration)
        {
            _httpClient = httpClient;
            _openIdConnectService = openIdConnectService;
            _configuration = configuration;

            _httpClient.BaseAddress = new Uri(configuration.Endpoint);
            _httpClient.DefaultRequestHeaders.Add("Accept", MediaTypeNames.Application.Json);
        }

        public async Task AuthenticateAsync()
        {
            if (_httpClient.DefaultRequestHeaders.Authorization != null &&
                _httpClient.DefaultRequestHeaders.Authorization.Scheme !=
                OidcConstants.AuthenticationSchemes.AuthorizationHeaderBearer)
                throw new AuthenticationException("Already seems to be authenticated");

            var disco = await _openIdConnectService.GetDiscoveryDocumentAsync();
            var token = await _openIdConnectService.GetTokenClientCredentialsAsync(disco.TokenEndpoint,
                _configuration.ClientId, _configuration.ClientSecret);

            if (token.IsError)
                throw new AuthenticationException(token.Error);

            _httpClient.DefaultRequestHeaders.Authorization =
                new AuthenticationHeaderValue(OidcConstants.AuthenticationSchemes.AuthorizationHeaderBearer,
                    token.AccessToken);

            await StartEventHub(token.AccessToken);
        }

        private async Task StartEventHub(string accessToken)
        {
            var uri = new Uri(_configuration.Endpoint);
            var eventEndpoint = $"{uri.Scheme}://{uri.Host}:{uri.Port}/EventHub";
            _hubConnection = new HubConnectionBuilder()
                .WithUrl(eventEndpoint)
                .WithAutomaticReconnect()
                .AddJsonProtocol()
                .Build();
            _hubConnection.On("Event", (EventMessage @event) => EventCallback?.Invoke(@event));

            await _hubConnection.StartAsync();
            await _hubConnection.SendAsync("authenticate", accessToken);
        }

        public async Task<string> GetCurrentUserCodeAsync()
        {
            var response = await _httpClient.GetAsync(ResourceEndpoints.CURRENTUSER_RESOURCE);

            if (!response.IsSuccessStatusCode)
                throw new Exception(response.ReasonPhrase);

            var jsonString = await response.Content.ReadAsStringAsync();
            var json = JsonConvert.DeserializeObject<JObject>(jsonString);
            return json["code"].Value<string>();
        }

        public async Task<List<UserRoot>> GetCurrentUserRootsAsync()
        {
            var response = await _httpClient.GetAsync(ResourceEndpoints.MYROOTS_RESOURCE);

            if (!response.IsSuccessStatusCode)
                throw new Exception(response.ReasonPhrase);

            var jsonString = await response.Content.ReadAsStringAsync();

            return JsonConvert.DeserializeObject<List<UserRoot>>(jsonString);
        }
        
        public async Task<Item> GetItemAsync(string itemCode, string itemType = null, JObject dataFilter = null)
        {
            if (dataFilter == null)
                return await GetItemSingleAsync(itemCode, itemType);

            var items = await GetItemsAsync(itemCode, itemType, dataFilter);
            return items[0];
        }
        
        public async Task<List<Item>> GetItemsAsync(string itemCode, string itemType = null, JObject dataFilter = null)
        {
            var resourceUri = string.Format(ResourceEndpoints.ITEMS_RESOURCE, itemCode);

            var queryString = HttpUtility.ParseQueryString(string.Empty);
            
            if(itemType != null)
                queryString["it"] = itemType;
            
            if(dataFilter != null)
                queryString["df"] =  dataFilter.ToString(Formatting.None);

            resourceUri = (queryString.Count > 0 ? $"{resourceUri}?" : resourceUri) + queryString;
            
            var response = await _httpClient.GetAsync(resourceUri);

            if (!response.IsSuccessStatusCode)
            {
                if (response.StatusCode == HttpStatusCode.NotFound)
                    return null;
                
                throw new Exception(response.ReasonPhrase);
            }

            var jsonString = await response.Content.ReadAsStringAsync();
            return JsonConvert.DeserializeObject<List<Item>>(jsonString);
        }

        private async Task<Item> GetItemSingleAsync(string itemCode, string itemType = null)
        {
            var resourceUri = string.Format(ResourceEndpoints.ITEMS_RESOURCE, itemCode);

            if (!string.IsNullOrEmpty(itemType))
                resourceUri = $"{resourceUri}/{itemType}";
            
            var response = await _httpClient.GetAsync(resourceUri);
            
            if (!response.IsSuccessStatusCode)
            {
                if (response.StatusCode == HttpStatusCode.NotFound)
                    return null;
                
                throw new Exception(response.ReasonPhrase);
            }

            var jsonString = await response.Content.ReadAsStringAsync();
            return JsonConvert.DeserializeObject<Item>(jsonString);
        }
        
        public async Task<List<Item>> GetItemChildrenAsync(string itemCode, string itemType = null, JObject dataFilter = null)
        {
            var resourceUri = string.Format(ResourceEndpoints.ITEMS_CHILDREN_RESOURCE, itemCode);
            
            var queryString = HttpUtility.ParseQueryString(string.Empty);
            
            if(itemType != null) 
                queryString["it"] = itemType;
            
            if(dataFilter != null)
                queryString["df"] =  dataFilter.ToString(Formatting.None);

            resourceUri = (queryString.Count > 0 ? $"{resourceUri}?" : resourceUri) + queryString;

            var response = await _httpClient.GetAsync(resourceUri);

            if (!response.IsSuccessStatusCode)
                throw new Exception(response.ReasonPhrase);

            var jsonString = await response.Content.ReadAsStringAsync();
            return JsonConvert.DeserializeObject<List<Item>>(jsonString);
        }

        public async Task<Item> CreateItemAsync(ItemRequest itemRequest)
        {
            var jsonString = JsonConvert.SerializeObject(itemRequest);

            var content = new StringContent(jsonString,  Encoding.UTF8,MediaTypeNames.Application.Json);
            var response = await _httpClient.PostAsync(ResourceEndpoints.ITEMS_CREATE_RESOURCE, 
                content);

            if (!response.IsSuccessStatusCode)
                throw new Exception(response.ReasonPhrase);
            
            var jsonStringResponse = await response.Content.ReadAsStringAsync();
            return JsonConvert.DeserializeObject<Item>(jsonStringResponse);
        }

        public async Task DeleteItemAsync(string itemCode)
        {
            var resourceUri = string.Format(ResourceEndpoints.ITEMS_RESOURCE, itemCode);
            var response = await _httpClient.DeleteAsync(resourceUri);

            if (!response.IsSuccessStatusCode)
                throw new Exception(response.ReasonPhrase);
        }
        
        public async Task DeleteItemsAsync(IList<string> itemCodes)
        {
            var jsonString = JsonConvert.SerializeObject(itemCodes);
            var content = new StringContent(jsonString);   
            var response = await _httpClient.PostAsync(ResourceEndpoints.ITEMS_DELETE_RESOURCE, content);

            if (!response.IsSuccessStatusCode)
                throw new Exception(response.ReasonPhrase);
        }

        public async Task DownloadItemAsync(string itemCode, string filePath)
        {
            var resourceUri = string.Format(ResourceEndpoints.ITEMS_DOWNLOAD_RESOURCE, itemCode);
            var response = await _httpClient.GetAsync(resourceUri, HttpCompletionOption.ResponseHeadersRead);
            
            if(response.IsSuccessStatusCode)
            {
                await using Stream streamToReadFrom = await response.Content.ReadAsStreamAsync();
                await using Stream streamToWriteTo = File.Open(filePath, FileMode.Create);
                await streamToReadFrom.CopyToAsync(streamToWriteTo);
            }
            else
            {
                throw new FileNotFoundException(response.ReasonPhrase);   
            }
        }

        public async Task<string> QueueTaskAsync(string itemCode, TaskRequest taskRequest)
        {
            var resourceUri = string.Format(ResourceEndpoints.ITEMTASK_REQUEST_RESOURCE, itemCode);

            var jsonString = JsonConvert.SerializeObject(taskRequest);
            var content = new StringContent(jsonString,  Encoding.UTF8,MediaTypeNames.Application.Json);
            var response = await _httpClient.PostAsync(resourceUri, content);

            if (!response.IsSuccessStatusCode)
                throw new Exception(response.ReasonPhrase);
            
            var jsonStringResponse = await response.Content.ReadAsStringAsync();
            var json = JsonConvert.DeserializeObject<JObject>(jsonStringResponse);
            
            return json["code"].Value<string>();
        }

        public async Task<List<ItemTaskStatus>> GetTasksStatusAsync(string itemCode)
        {
            var resourceUri = string.Format(ResourceEndpoints.ITEMTASKS_RESOURCE, itemCode);
            var response = await _httpClient.GetAsync(resourceUri);

            if (!response.IsSuccessStatusCode)
                throw new Exception(response.ReasonPhrase);

            var jsonString = await response.Content.ReadAsStringAsync();
            return JsonConvert.DeserializeObject<List<ItemTaskStatus>>(jsonString);
        }

        public async Task<ItemTaskStatus> GetTaskStatusAsync(string itemCode, string itemTaskCode)
        {
            var resourceUri = string.Format(ResourceEndpoints.ITEMTASK_RESOURCE, itemCode, itemTaskCode);
            var response = await _httpClient.GetAsync(resourceUri);

            if (!response.IsSuccessStatusCode)
                throw new Exception(response.ReasonPhrase);

            var jsonString = await response.Content.ReadAsStringAsync();
            return JsonConvert.DeserializeObject<ItemTaskStatus>(jsonString);
        }
    }
}