using System.Net.Http.Json;
using System.Text.Json;
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.DependencyInjection;

public static class ScenarioReplayHelper
{
    private static readonly JsonSerializerOptions JsonOptions = new()
    {
        PropertyNameCaseInsensitive = true,
    };

    public static string ScenariosDirectory =>
        Path.GetFullPath(Path.Combine(
            AppContext.BaseDirectory,
            "..", "..", "..", "..",
            "VigilCare.Simulator", "Scenarios", "List"));

    public static ScenarioFile Load(string fileName)
    {
        var path = Path.Combine(ScenariosDirectory, fileName);
        var json = File.ReadAllText(path);
        return JsonSerializer.Deserialize<ScenarioFile>(json, JsonOptions)
            ?? throw new InvalidOperationException($"Failed to deserialize {path}");
    }

    public static async Task<(Guid PatientId, Guid EncounterId)> ReplayObservationsAsync(
        HttpClient client,
        ScenarioFile scenario,
        IServiceProvider services,
        CancellationToken ct = default)
    {
        var result = await ReplayObservationsCoreAsync(client, scenario, ct);
        await WaitForOutboxDrainAsync(services, TimeSpan.FromSeconds(30), ct);
        await RunClinicalEnginesForEncounterAsync(services, result.EncounterId, ct);
        return result;
    }

    /// <summary>
    /// Replays persisted observations through the clinical detectors in encounter order.
    /// Scenario E2E tests use this after HTTP ingest so assertions do not depend on
    /// shared Kafka consumer lag across the integration suite.
    /// </summary>
    public static async Task RunClinicalEnginesForEncounterAsync(
        IServiceProvider services,
        Guid encounterId,
        CancellationToken ct = default)
    {
        using var scope = services.CreateScope();
        var db = scope.ServiceProvider.GetRequiredService<AppDbContext>();

        var encounter = await db.Encounters
            .AsNoTracking()
            .FirstOrDefaultAsync(e => e.Id == encounterId, ct)
            ?? throw new InvalidOperationException($"Encounter {encounterId} not found");

        var observations = await db.Observations
            .AsNoTracking()
            .Where(o => o.EncounterId == encounterId)
            .OrderBy(o => o.RecordedAt)
            .ThenBy(o => o.CreatedAt)
            .ToListAsync(ct);

        var qsofa = scope.ServiceProvider.GetRequiredService<QsofaDetector>();
        var gcs = scope.ServiceProvider.GetRequiredService<GcsDetector>();
        var sofa = scope.ServiceProvider.GetRequiredService<SofaDetector>();

        foreach (var obs in observations)
        {
            await qsofa.ProcessObservationAsync(
                encounterId, encounter.PatientId, obs.ObservationCode, obs.Value, ct);

            var gcsResult = await gcs.ProcessObservationAsync(
                encounterId, encounter.PatientId, obs.ObservationCode, obs.Value, ct);
            if (gcsResult.Outcome == GcsOutcome.ScoreComputed)
            {
                await sofa.ProcessGcsScoredAsync(
                    encounterId, encounter.PatientId, ct);
            }

            await sofa.ProcessObservationAsync(
                encounterId,
                encounter.PatientId,
                obs.ObservationCode,
                obs.Value,
                obs.RecordedAt,
                ct);
        }

        await qsofa.SyncAlteredMentationAsync(encounterId, encounter.PatientId, ct);
    }

    public static async Task WaitForOutboxDrainAsync(
        IServiceProvider services,
        TimeSpan timeout,
        CancellationToken ct = default)
    {
        var deadline = DateTime.UtcNow + timeout;
        while (DateTime.UtcNow < deadline)
        {
            using var scope = services.CreateScope();
            var db = scope.ServiceProvider.GetRequiredService<AppDbContext>();
            var pending = await db.OutboxEvents.CountAsync(
                e => e.ProcessedAt == null && e.FailedAt == null, ct);
            if (pending == 0)
                return;
            await Task.Delay(250, ct);
        }

        throw new TimeoutException("Timed out waiting for outbox relay to drain pending events");
    }

    private static async Task<(Guid PatientId, Guid EncounterId)> ReplayObservationsCoreAsync(
        HttpClient client,
        ScenarioFile scenario,
        CancellationToken ct)
    {
        var patientResp = await client.PostAsJsonAsync("/api/v1/patients", new
        {
            firstName = scenario.Patient.FirstName,
            lastName = scenario.Patient.LastName,
            dateOfBirth = scenario.Patient.DateOfBirth,
            gender = scenario.Patient.Gender,
        }, ct);
        patientResp.EnsureSuccessStatusCode();
        var patient = (await patientResp.Content.ReadFromJsonAsync<ApiEnvelope<PatientDto>>(ct))!.Data;

        var encounterResp = await client.PostAsJsonAsync(
            $"/api/v1/patients/{patient.Id}/encounters",
            new
            {
                encounterType = scenario.Encounter.EncounterType,
                department = scenario.Encounter.Department,
                attendingPhysician = scenario.Encounter.AttendingPhysician,
                roomBed = scenario.Encounter.RoomBed,
                admissionReason = scenario.Encounter.AdmissionReason,
            }, ct);
        encounterResp.EnsureSuccessStatusCode();
        var encounter = (await encounterResp.Content.ReadFromJsonAsync<ApiEnvelope<EncounterDto>>(ct))!.Data;

        var start = DateTimeOffset.UtcNow;
        foreach (var cluster in scenario.Events
            .Where(e => e.Type == "observation")
            .GroupBy(e => e.OffsetMinutes)
            .OrderBy(g => g.Key))
        {
            var recordedAt = start.AddMinutes(cluster.Key);
            var batch = cluster.Select(evt =>
            {
                var code = evt.Data.GetProperty("code").GetString()!;
                var value = evt.Data.GetProperty("value").GetDecimal();
                var unit = evt.Data.GetProperty("unit").GetString()!;
                var source = evt.Data.TryGetProperty("source", out var s) ? s.GetString()! : "Manual";
                return new
                {
                    observationCode = code,
                    value,
                    unit,
                    source = MapSource(source),
                    recordedAt,
                };
            }).ToList();

            foreach (var chunk in batch.Chunk(10))
            {
                var resp = await client.PostAsJsonAsync(
                    $"/api/v1/encounters/{encounter.Id}/observations",
                    new { observations = chunk }, ct);
                resp.EnsureSuccessStatusCode();
            }
        }

        return (patient.Id, encounter.Id);
    }

    public static async Task<SofaScore> WaitForSofaScoreAsync(
        IServiceProvider services,
        Guid encounterId,
        TimeSpan timeout,
        Func<SofaScore, bool>? predicate = null)
    {
        var deadline = DateTime.UtcNow + timeout;
        while (DateTime.UtcNow < deadline)
        {
            using var scope = services.CreateScope();
            var db = scope.ServiceProvider.GetRequiredService<AppDbContext>();
            var sofa = await db.SofaScores
                .Where(s => s.EncounterId == encounterId)
                .OrderByDescending(s => s.CalculatedAt)
                .FirstOrDefaultAsync();
            if (sofa is not null && (predicate is null || predicate(sofa)))
                return sofa;
            await Task.Delay(500);
        }
        throw new TimeoutException($"Timed out waiting for SOFA score on encounter {encounterId}");
    }

    public static async Task WaitForAlertTypeAsync(
        IServiceProvider services,
        Guid encounterId,
        AlertType alertType,
        TimeSpan timeout)
    {
        var deadline = DateTime.UtcNow + timeout;
        while (DateTime.UtcNow < deadline)
        {
            using var scope = services.CreateScope();
            var db = scope.ServiceProvider.GetRequiredService<AppDbContext>();
            if (await db.ClinicalAlerts.AnyAsync(a =>
                    a.EncounterId == encounterId && a.AlertType == alertType))
                return;
            await Task.Delay(500);
        }
        throw new TimeoutException($"Timed out waiting for {alertType} on encounter {encounterId}");
    }

    public static async Task AssertNoAlertTypeAsync(
        IServiceProvider services,
        Guid encounterId,
        AlertType alertType,
        TimeSpan settleDelay)
    {
        await Task.Delay(settleDelay);
        using var scope = services.CreateScope();
        var db = scope.ServiceProvider.GetRequiredService<AppDbContext>();
        var found = await db.ClinicalAlerts.AnyAsync(a =>
            a.EncounterId == encounterId && a.AlertType == alertType);
        if (found)
            throw new InvalidOperationException($"Unexpected {alertType} alert on encounter {encounterId}");
    }

    private static string MapSource(string source) => source.ToLowerInvariant() switch
    {
        "device" or "monitor" => "Device",
        "lab" => "Lab",
        _ => "Manual",
    };

    private record ApiEnvelope<T>(T Data);
    private record PatientDto(Guid Id);
    private record EncounterDto(Guid Id);
}