using Google.Apis.AndroidPublisher.v3;
using Google.Apis.Auth.OAuth2;
using Google.Apis.Services;

const string PackageName = "it.liviomerola.lmemappecatastali.pro";
const string ProductId = "lme_pro";

var builder = WebApplication.CreateBuilder(args);
builder.Services.AddSingleton(_ =>
{
    var credential = GoogleCredential.GetApplicationDefault()
        .CreateScoped(AndroidPublisherService.Scope.Androidpublisher);
    return new AndroidPublisherService(new BaseClientService.Initializer
    {
        HttpClientInitializer = credential,
        ApplicationName = "LME Play subscription verifier"
    });
});

var app = builder.Build();
app.UseHttpsRedirection();

app.MapGet("/health", () => Results.Ok(new { status = "ok" }));
app.MapPost("/v1/google-play/subscriptions/verify", async (
    VerifySubscriptionRequest request,
    AndroidPublisherService publisher,
    CancellationToken cancellationToken) =>
{
    if (request.PackageName != PackageName || request.ProductId != ProductId
        || string.IsNullOrWhiteSpace(request.PurchaseToken))
    {
        return Results.BadRequest(new VerifySubscriptionResponse(false, null, "Richiesta non valida."));
    }

    try
    {
        var purchase = await publisher.Purchases.Subscriptionsv2
            .Get(PackageName, request.PurchaseToken)
            .ExecuteAsync(cancellationToken);
        var active = purchase.SubscriptionState is "SUBSCRIPTION_STATE_ACTIVE"
            or "SUBSCRIPTION_STATE_IN_GRACE_PERIOD";
        var expiresAt = purchase.LineItems?
            .Select(item => item.ExpiryTimeDateTimeOffset)
            .Where(value => value.HasValue)
            .Max();
        return Results.Ok(new VerifySubscriptionResponse(
            active,
            expiresAt,
            active ? "Abbonamento LME Pro verificato." : "L'abbonamento Google Play non risulta attivo."));
    }
    catch (Google.GoogleApiException error) when ((int)error.HttpStatusCode is 400 or 404)
    {
        return Results.Ok(new VerifySubscriptionResponse(false, null, "Acquisto Google Play non riconosciuto."));
    }
});

app.Run();

internal sealed record VerifySubscriptionRequest(string PackageName, string ProductId, string PurchaseToken);
internal sealed record VerifySubscriptionResponse(bool Active, DateTimeOffset? ExpiresAt, string Message);