using System.Text.Json;

using Microsoft.Extensions.Caching.Memory;

namespace MesaFabApproval.Client.Services;

public interface ICustomerService {
    Task<IEnumerable<string>> GetAllCustomerNames();
}

public class CustomerService : ICustomerService {
    private readonly IMemoryCache _cache;
    private readonly IHttpClientFactory _httpClientFactory;

    public CustomerService(IMemoryCache cache, IHttpClientFactory httpClientFactory) {
        _cache = cache ?? throw new ArgumentNullException("IMemoryCache not injected");
        _httpClientFactory = httpClientFactory ??
            throw new ArgumentNullException("IHttpClientFactory not injected");
    }

    public async Task<IEnumerable<string>> GetAllCustomerNames() {
        IEnumerable<string>? allCustomerNames = null;

        allCustomerNames = _cache.Get<IEnumerable<string>>("allCustomerNames");

        if (allCustomerNames is null) {
            HttpClient httpClient = _httpClientFactory.CreateClient("API");

            HttpRequestMessage requestMessage = new(HttpMethod.Get, $"customer/all");

            HttpResponseMessage responseMessage = await httpClient.SendAsync(requestMessage);

            if (responseMessage.IsSuccessStatusCode) {
                string responseContent = await responseMessage.Content.ReadAsStringAsync();

                JsonSerializerOptions jsonSerializerOptions = new() {
                    PropertyNameCaseInsensitive = true
                };

                allCustomerNames = JsonSerializer.Deserialize<IEnumerable<string>>(responseContent, jsonSerializerOptions) ??
                    throw new Exception("Unable to parse names from API response");

                _cache.Set($"allCustomerNames", allCustomerNames, DateTimeOffset.Now.AddHours(1));
            } else {
                throw new Exception($"Unable to get all customer names, because {responseMessage.ReasonPhrase}");
            }
        }

        return allCustomerNames;
    }
}