using System.Diagnostics;
using System.Net;
using System.Net.Http.Json;
using AdminPanel.Models;

namespace AdminPanel.Services;

public class HttpUsersService : IUsersService
{
    private HttpClient Client { get; }

    public HttpUsersService(HttpClient client)
    {
        this.Client = client;
    }

    private record ServerErrorMessageDto(string? Field, string? Error, string Message);

    private async Task EnsureResponseIsOk(HttpResponseMessage response)
    {

        if (response.StatusCode == HttpStatusCode.OK)
        {
            return;
        }
        
        var content = await response.Content.ReadFromJsonAsync<ServerErrorMessageDto[]>();
        var messages = content!
            .GroupBy(e => e.Field ?? e.Error!)
            .ToDictionary(
                g => g.Key,
                g => g.ToList().ConvertAll(e => e.Message)
            );

        throw new ServiceException("Server refused request", messages);
    }

    private record ListUsersResponseDto(List<User> Users, uint TotalCount);

    public async Task<(uint, List<User>)> ListUsers(uint from, uint len, string? searchString = null)
    {
        var httpResponse =
            await Client.GetAsync($"/api/admin/list-users?start={from}&n={len}&search={searchString ?? ""}");
        await EnsureResponseIsOk(httpResponse);

        var response = await httpResponse.Content.ReadFromJsonAsync<ListUsersResponseDto>()
                       ?? throw new Exception("Received non-parseable json from server");

        return (response.TotalCount, response.Users);
    }

    private record AddUserRequestDto(string Username, string Email, string Password, bool IsAdmin);

    private record AddUserResponseDto(uint Id);

    public async Task<User> AddUser(string username, string email, string password, bool isAdmin)
    {
        var httpResponse = await Client.PostAsJsonAsync("/api/admin/user/add",
            new AddUserRequestDto(username, email, password, isAdmin));

        await EnsureResponseIsOk(httpResponse);

        var response = await httpResponse.Content.ReadFromJsonAsync<AddUserResponseDto>()
                       ?? throw new Exception("Received non-parseable json from server");

        return new User
        {
            Name = username,
            Email = email,
            IsAdmin = isAdmin,
            Id = response.Id
        };
    }

    private record RemoveUsersRequestDto(uint[] Identifiers);

    public async Task RemoveUsers(IEnumerable<uint> userIds)
    {
        var httpResponse =
            await Client.PostAsJsonAsync("/api/admin/user/remove-all", new RemoveUsersRequestDto(userIds.ToArray()));
        
        await EnsureResponseIsOk(httpResponse);
    }

    private record UpdateUserRequestDto(string Email, string Username, bool IsAdmin);

    public async Task UpdateUser(User user)
    {
        var httpResponse = await Client.PostAsJsonAsync($"/api/admin/user/{user.Id}/update",
            new UpdateUserRequestDto(user.Email, user.Name, user.IsAdmin));
        await EnsureResponseIsOk(httpResponse);
    }
}