using System.Globalization;
using System.Net.Http.Headers;
using System.Linq;
using System.Text.Json;
using StackExchange.Redis;

static string RequireEnv(string name)
{
    var value = Environment.GetEnvironmentVariable(name);
    if (string.IsNullOrWhiteSpace(value))
    {
        throw new InvalidOperationException($"Environment variable '{name}' is required for Notify smoke validation.");
    }

    return value;
}

static string? GetField(StreamEntry entry, string fieldName)
{
    foreach (var pair in entry.Values)
    {
        if (string.Equals(pair.Name, fieldName, StringComparison.OrdinalIgnoreCase))
        {
            return pair.Value.ToString();
        }
    }

    return null;
}

static void Ensure(bool condition, string message)
{
    if (!condition)
    {
        throw new InvalidOperationException(message);
    }
}

var redisDsn = RequireEnv("NOTIFY_SMOKE_REDIS_DSN");
var redisStream = Environment.GetEnvironmentVariable("NOTIFY_SMOKE_STREAM");
if (string.IsNullOrWhiteSpace(redisStream))
{
    redisStream = "stella.events";
}

var expectedKindsEnv = RequireEnv("NOTIFY_SMOKE_EXPECT_KINDS");

var expectedKinds = expectedKindsEnv
    .Split(',', StringSplitOptions.RemoveEmptyEntries | StringSplitOptions.TrimEntries)
    .Select(kind => kind.ToLowerInvariant())
    .Distinct()
    .ToArray();
Ensure(expectedKinds.Length > 0, "Expected at least one event kind in NOTIFY_SMOKE_EXPECT_KINDS.");

var lookbackMinutesEnv = RequireEnv("NOTIFY_SMOKE_LOOKBACK_MINUTES");
if (!double.TryParse(lookbackMinutesEnv, NumberStyles.Any, CultureInfo.InvariantCulture, out var lookbackMinutes))
{
    throw new InvalidOperationException("NOTIFY_SMOKE_LOOKBACK_MINUTES must be numeric.");
}
Ensure(lookbackMinutes > 0, "NOTIFY_SMOKE_LOOKBACK_MINUTES must be greater than zero.");

var now = DateTimeOffset.UtcNow;
var sinceThreshold = now - TimeSpan.FromMinutes(Math.Max(1, lookbackMinutes));

Console.WriteLine($"ℹ️  Checking Redis stream '{redisStream}' for kinds [{string.Join(", ", expectedKinds)}] within the last {lookbackMinutes:F1} minutes.");

var redisConfig = ConfigurationOptions.Parse(redisDsn);
redisConfig.AbortOnConnectFail = false;

await using var redisConnection = await ConnectionMultiplexer.ConnectAsync(redisConfig);
var database = redisConnection.GetDatabase();

var streamEntries = await database.StreamRangeAsync(redisStream, "-", "+", count: 200);
if (streamEntries.Length > 1)
{
    Array.Reverse(streamEntries);
}
Ensure(streamEntries.Length > 0, $"Redis stream '{redisStream}' is empty.");

var recentEntries = new List<StreamEntry>();
foreach (var entry in streamEntries)
{
    var timestampText = GetField(entry, "ts");
    if (timestampText is null)
    {
        continue;
    }

    if (!DateTimeOffset.TryParse(timestampText, CultureInfo.InvariantCulture, DateTimeStyles.AssumeUniversal | DateTimeStyles.AdjustToUniversal, out var entryTimestamp))
    {
        continue;
    }

    if (entryTimestamp >= sinceThreshold)
    {
        recentEntries.Add(entry);
    }
}

Ensure(recentEntries.Count > 0, $"No Redis events newer than {sinceThreshold:u} located in stream '{redisStream}'.");

var missingKinds = new List<string>();
foreach (var kind in expectedKinds)
{
    var match = recentEntries.FirstOrDefault(entry =>
    {
        var entryKind = GetField(entry, "kind")?.ToLowerInvariant();
        return entryKind == kind;
    });

    if (match.Equals(default(StreamEntry)))
    {
        missingKinds.Add(kind);
    }
}

Ensure(missingKinds.Count == 0, $"Missing expected Redis events for kinds: {string.Join(", ", missingKinds)}");

Console.WriteLine("✅ Redis event stream contains the expected scanner events.");

var notifyBaseUrl = RequireEnv("NOTIFY_SMOKE_NOTIFY_BASEURL").TrimEnd('/');
var notifyToken = RequireEnv("NOTIFY_SMOKE_NOTIFY_TOKEN");
var notifyTenant = RequireEnv("NOTIFY_SMOKE_NOTIFY_TENANT");
var notifyTenantHeader = Environment.GetEnvironmentVariable("NOTIFY_SMOKE_NOTIFY_TENANT_HEADER");
if (string.IsNullOrWhiteSpace(notifyTenantHeader))
{
    notifyTenantHeader = "X-StellaOps-Tenant";
}

var notifyTimeoutSeconds = 30;
var notifyTimeoutEnv = Environment.GetEnvironmentVariable("NOTIFY_SMOKE_NOTIFY_TIMEOUT_SECONDS");
if (!string.IsNullOrWhiteSpace(notifyTimeoutEnv) && int.TryParse(notifyTimeoutEnv, NumberStyles.Integer, CultureInfo.InvariantCulture, out var parsedTimeout))
{
    notifyTimeoutSeconds = Math.Max(5, parsedTimeout);
}

using var httpClient = new HttpClient
{
    Timeout = TimeSpan.FromSeconds(notifyTimeoutSeconds),
};

httpClient.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", notifyToken);
httpClient.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
httpClient.DefaultRequestHeaders.Add(notifyTenantHeader, notifyTenant);

var sinceQuery = Uri.EscapeDataString(sinceThreshold.ToString("O", CultureInfo.InvariantCulture));
var deliveriesUrl = $"{notifyBaseUrl}/api/v1/deliveries?since={sinceQuery}&limit=200";

Console.WriteLine($"ℹ️  Querying Notify deliveries via {deliveriesUrl}.");

using var response = await httpClient.GetAsync(deliveriesUrl);
if (!response.IsSuccessStatusCode)
{
    var body = await response.Content.ReadAsStringAsync();
    throw new InvalidOperationException($"Notify deliveries request failed with {(int)response.StatusCode} {response.ReasonPhrase}: {body}");
}

var json = await response.Content.ReadAsStringAsync();
if (string.IsNullOrWhiteSpace(json))
{
    throw new InvalidOperationException("Notify deliveries response body was empty.");
}

using var document = JsonDocument.Parse(json);
var root = document.RootElement;

IEnumerable<JsonElement> EnumerateDeliveries(JsonElement element)
{
    return element.ValueKind switch
    {
        JsonValueKind.Array => element.EnumerateArray(),
        JsonValueKind.Object when element.TryGetProperty("items", out var items) && items.ValueKind == JsonValueKind.Array => items.EnumerateArray(),
        _ => throw new InvalidOperationException("Notify deliveries response was not an array or did not contain an 'items' collection.")
    };
}

var deliveries = EnumerateDeliveries(root).ToArray();
Ensure(deliveries.Length > 0, "Notify deliveries response did not return any records.");

var missingDeliveryKinds = new List<string>();
foreach (var kind in expectedKinds)
{
    var found = deliveries.Any(delivery =>
        delivery.TryGetProperty("kind", out var kindProperty) &&
        kindProperty.GetString()?.Equals(kind, StringComparison.OrdinalIgnoreCase) == true &&
        delivery.TryGetProperty("status", out var statusProperty) &&
        !string.Equals(statusProperty.GetString(), "failed", StringComparison.OrdinalIgnoreCase));

    if (!found)
    {
        missingDeliveryKinds.Add(kind);
    }
}

Ensure(missingDeliveryKinds.Count == 0, $"Notify deliveries missing successful records for kinds: {string.Join(", ", missingDeliveryKinds)}");

Console.WriteLine("✅ Notify deliveries include the expected scanner events.");
Console.WriteLine("🎉 Notify smoke validation completed successfully.");