using Bit.Core.Settings;
using Microsoft.Extensions.Options;

namespace Bit.Admin.HostedServices;

public abstract class BlockIpHostedService : IHostedService, IDisposable
{
    protected readonly ILogger<BlockIpHostedService> _logger;
    protected readonly GlobalSettings _globalSettings;
    private readonly AdminSettings _adminSettings;

    private Task _executingTask;
    private CancellationTokenSource _cts;
    private HttpClient _httpClient = new HttpClient();

    public BlockIpHostedService(
        ILogger<BlockIpHostedService> logger,
        IOptions<AdminSettings> adminSettings,
        GlobalSettings globalSettings)
    {
        _logger = logger;
        _globalSettings = globalSettings;
        _adminSettings = adminSettings?.Value;
    }

    public Task StartAsync(CancellationToken cancellationToken)
    {
        _cts = CancellationTokenSource.CreateLinkedTokenSource(cancellationToken);
        _executingTask = ExecuteAsync(_cts.Token);
        return _executingTask.IsCompleted ? _executingTask : Task.CompletedTask;
    }

    public async Task StopAsync(CancellationToken cancellationToken)
    {
        if (_executingTask == null)
        {
            return;
        }
        _cts.Cancel();
        await Task.WhenAny(_executingTask, Task.Delay(-1, cancellationToken));
        cancellationToken.ThrowIfCancellationRequested();
    }

    public virtual void Dispose()
    { }

    protected abstract Task ExecuteAsync(CancellationToken cancellationToken);

    protected async Task BlockIpAsync(string message, CancellationToken cancellationToken)
    {
        var request = new HttpRequestMessage();
        request.Headers.Accept.Clear();
        request.Headers.Add("X-Auth-Email", _adminSettings.Cloudflare.AuthEmail);
        request.Headers.Add("X-Auth-Key", _adminSettings.Cloudflare.AuthKey);
        request.Method = HttpMethod.Post;
        request.RequestUri = new Uri("https://api.cloudflare.com/" +
            $"client/v4/zones/{_adminSettings.Cloudflare.ZoneId}/firewall/access_rules/rules");

        request.Content = JsonContent.Create(new
        {
            mode = "block",
            configuration = new
            {
                target = "ip",
                value = message
            },
            notes = $"Rate limit abuse on {DateTime.UtcNow.ToString()}."
        });

        var response = await _httpClient.SendAsync(request, cancellationToken);
        if (!response.IsSuccessStatusCode)
        {
            return;
        }

        var accessRuleResponse = await response.Content.ReadFromJsonAsync<AccessRuleResponse>(cancellationToken: cancellationToken);
        if (!accessRuleResponse.Success)
        {
            return;
        }

        // TODO: Send `accessRuleResponse.Result?.Id` message to unblock queue
    }

    protected async Task UnblockIpAsync(string message, CancellationToken cancellationToken)
    {
        if (string.IsNullOrWhiteSpace(message))
        {
            return;
        }

        if (message.Contains(".") || message.Contains(":"))
        {
            // IP address messages
            var request = new HttpRequestMessage();
            request.Headers.Accept.Clear();
            request.Headers.Add("X-Auth-Email", _adminSettings.Cloudflare.AuthEmail);
            request.Headers.Add("X-Auth-Key", _adminSettings.Cloudflare.AuthKey);
            request.Method = HttpMethod.Get;
            request.RequestUri = new Uri("https://api.cloudflare.com/" +
                $"client/v4/zones/{_adminSettings.Cloudflare.ZoneId}/firewall/access_rules/rules?" +
                $"configuration_target=ip&configuration_value={message}");

            var response = await _httpClient.SendAsync(request, cancellationToken);
            if (!response.IsSuccessStatusCode)
            {
                return;
            }

            var listResponse = await response.Content.ReadFromJsonAsync<ListResponse>(cancellationToken: cancellationToken);
            if (!listResponse.Success)
            {
                return;
            }

            foreach (var rule in listResponse.Result)
            {
                await DeleteAccessRuleAsync(rule.Id, cancellationToken);
            }
        }
        else
        {
            // Rule Id messages
            await DeleteAccessRuleAsync(message, cancellationToken);
        }
    }

    protected async Task DeleteAccessRuleAsync(string ruleId, CancellationToken cancellationToken)
    {
        var request = new HttpRequestMessage();
        request.Headers.Accept.Clear();
        request.Headers.Add("X-Auth-Email", _adminSettings.Cloudflare.AuthEmail);
        request.Headers.Add("X-Auth-Key", _adminSettings.Cloudflare.AuthKey);
        request.Method = HttpMethod.Delete;
        request.RequestUri = new Uri("https://api.cloudflare.com/" +
            $"client/v4/zones/{_adminSettings.Cloudflare.ZoneId}/firewall/access_rules/rules/{ruleId}");
        await _httpClient.SendAsync(request, cancellationToken);
    }

    public class ListResponse
    {
        public bool Success { get; set; }
        public List<AccessRuleResultResponse> Result { get; set; }
    }

    public class AccessRuleResponse
    {
        public bool Success { get; set; }
        public AccessRuleResultResponse Result { get; set; }
    }

    public class AccessRuleResultResponse
    {
        public string Id { get; set; }
        public string Notes { get; set; }
        public ConfigurationResponse Configuration { get; set; }

        public class ConfigurationResponse
        {
            public string Target { get; set; }
            public string Value { get; set; }
        }
    }
}