using System;
using System.Collections.Generic;
using System.Net;
using System.Security.Cryptography;
using System.Text;
using System.Text.Json;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Mvc.Testing;
using Microsoft.Extensions.Configuration;

namespace StellaOps.Scheduler.WebService.Tests;

public sealed class EventWebhookEndpointTests : IClassFixture<WebApplicationFactory<Program>>
{
    static EventWebhookEndpointTests()
    {
        Environment.SetEnvironmentVariable("Scheduler__Events__Webhooks__Conselier__HmacSecret", ConselierSecret);
        Environment.SetEnvironmentVariable("Scheduler__Events__Webhooks__Conselier__Enabled", "true");
        Environment.SetEnvironmentVariable("Scheduler__Events__Webhooks__Excitor__HmacSecret", ExcitorSecret);
        Environment.SetEnvironmentVariable("Scheduler__Events__Webhooks__Excitor__Enabled", "true");
    }

    private const string ConselierSecret = "conselier-secret";
    private const string ExcitorSecret = "excitor-secret";

    private readonly WebApplicationFactory<Program> _factory;

    public EventWebhookEndpointTests(WebApplicationFactory<Program> factory)
    {
        _factory = factory;
    }

    [Trait("Category", TestCategories.Unit)]
        [Fact]
    public async Task ConselierWebhook_AcceptsValidSignature()
    {
        using var client = _factory.CreateClient();
        var payload = new
        {
            exportId = "conselier-exp-1",
            changedProductKeys = new[] { "pkg:rpm/openssl", "pkg:deb/nginx" },
            kev = new[] { "CVE-2024-0001" },
            window = new { from = DateTimeOffset.UtcNow.AddHours(-1), to = DateTimeOffset.UtcNow }
        };

        var json = JsonSerializer.Serialize(payload, new JsonSerializerOptions(JsonSerializerDefaults.Web));
        using var request = new HttpRequestMessage(HttpMethod.Post, "/events/conselier-export")
        {
            Content = new StringContent(json, Encoding.UTF8, "application/json")
        };
        request.Headers.TryAddWithoutValidation("X-Scheduler-Signature", ComputeSignature(ConselierSecret, json));

        var response = await client.SendAsync(request);
        Assert.Equal(HttpStatusCode.Accepted, response.StatusCode);
    }

    [Trait("Category", TestCategories.Unit)]
        [Fact]
    public async Task ConselierWebhook_RejectsInvalidSignature()
    {
        using var client = _factory.CreateClient();
        var payload = new
        {
            exportId = "conselier-exp-2",
            changedProductKeys = new[] { "pkg:nuget/log4net" }
        };

        var json = JsonSerializer.Serialize(payload, new JsonSerializerOptions(JsonSerializerDefaults.Web));
        using var request = new HttpRequestMessage(HttpMethod.Post, "/events/conselier-export")
        {
            Content = new StringContent(json, Encoding.UTF8, "application/json")
        };
        request.Headers.TryAddWithoutValidation("X-Scheduler-Signature", "sha256=invalid");

        var response = await client.SendAsync(request);
        Assert.Equal(HttpStatusCode.Unauthorized, response.StatusCode);
    }

    [Trait("Category", TestCategories.Unit)]
        [Fact]
    public async Task ExcitorWebhook_HonoursRateLimit()
    {
        using var restrictedFactory = _factory.WithWebHostBuilder(builder =>
        {
            builder.ConfigureAppConfiguration((_, configuration) =>
            {
                configuration.AddInMemoryCollection(new Dictionary<string, string?>
                {
                    ["Scheduler:Events:Webhooks:Excitor:RateLimitRequests"] = "1",
                    ["Scheduler:Events:Webhooks:Excitor:RateLimitWindowSeconds"] = "60"
                });
            });
        });

        using var client = restrictedFactory.CreateClient();
        var payload = new
        {
            exportId = "excitor-exp-1",
            changedClaims = new[]
            {
                new { productKey = "pkg:deb/openssl", vulnerabilityId = "CVE-2024-1234", status = "affected" }
            }
        };

        var json = JsonSerializer.Serialize(payload, new JsonSerializerOptions(JsonSerializerDefaults.Web));

        using var first = new HttpRequestMessage(HttpMethod.Post, "/events/excitor-export")
        {
            Content = new StringContent(json, Encoding.UTF8, "application/json")
        };
        first.Headers.TryAddWithoutValidation("X-Scheduler-Signature", ComputeSignature(ExcitorSecret, json));
        var firstResponse = await client.SendAsync(first);
        Assert.Equal(HttpStatusCode.Accepted, firstResponse.StatusCode);

        using var second = new HttpRequestMessage(HttpMethod.Post, "/events/excitor-export")
        {
            Content = new StringContent(json, Encoding.UTF8, "application/json")
        };
        second.Headers.TryAddWithoutValidation("X-Scheduler-Signature", ComputeSignature(ExcitorSecret, json));
        var secondResponse = await client.SendAsync(second);
        Assert.Equal((HttpStatusCode)429, secondResponse.StatusCode);
        Assert.True(secondResponse.Headers.Contains("Retry-After"));
    }

    private static string ComputeSignature(string secret, string payload)
    {
        using var hmac = new HMACSHA256(Encoding.UTF8.GetBytes(secret));
using StellaOps.TestKit;
        var hash = hmac.ComputeHash(Encoding.UTF8.GetBytes(payload));
        return "sha256=" + Convert.ToHexString(hash).ToLowerInvariant();
    }
}