using EntitlementBLL.Common;
using EntitlementBLL.Interfaces;
using EntitlementDAL.DTOs;
using EntitlementDAL.Interfaces;

namespace EntitlementBLL.Implementations;

public class ClientEntitlementSnapshotBLL : IClientEntitlementSnapshotBLL
{
    private readonly ISubscriptionService     _SubscriptionService;
    private readonly IPlanBLL                 _PlanBLL;
    private readonly IClientProvisioningDAL   _ClientProvisioningDAL;
    private readonly IEntitlementLoginFactory _LoginFactory;

    public ClientEntitlementSnapshotBLL(
        ISubscriptionService subscriptionService, IPlanBLL planBLL,
        IClientProvisioningDAL clientProvisioningDAL, IEntitlementLoginFactory loginFactory)
    {
        _SubscriptionService   = subscriptionService;
        _PlanBLL               = planBLL;
        _ClientProvisioningDAL = clientProvisioningDAL;
        _LoginFactory          = loginFactory;
    }

    public async Task<ClientEntitlementSnapshotDTO> GetSnapshotAsync(int clientId, CancellationToken ct)
    {
        // Real GB5 ClientIds are large negative AutoNumber-allocated values (e.g. -999999001),
        // never small positive ones — a "clientId <= 0" guard would reject every genuine client
        // and only let through malformed/uninitialized-int-default callers, which is exactly
        // backwards. Live-verified 2026-09-08: this rejected every real ClientId with a 400,
        // which SwBLL.Integration.EntitlementSubscriptionClient then turned into a thrown
        // InvalidOperationException, aborting Gate A/B rollout-campaign target resolution
        // entirely for any real client. Only reject the genuinely-missing/default case.
        if (clientId == 0) throw new ArgumentException("ClientId is required.", nameof(clientId));

        var login = _LoginFactory.Create(clientId);

        // ISubscriptionService.GetAsync throws EntitlementNotFoundException if no subscription
        // exists — a real, valid Gate-A answer ("this client has no subscription at all"), not
        // an error condition for this caller. Surfacing it as SubscriptionStatus=0 (Pending, the
        // same sentinel a never-activated subscription would carry) rather than propagating the
        // exception keeps the snapshot endpoint a plain data read, never a 4xx/5xx for a state
        // Gate A needs to reason about directly.
        SubscriptionDto? sub;
        try
        {
            sub = await _SubscriptionService.GetAsync(clientId, ct).ConfigureAwait(false);
        }
        catch (EntitlementBLL.Exceptions.EntitlementNotFoundException)
        {
            sub = null;
        }

        var enabledFeatureCodes = new List<string>();
        if (sub is not null)
        {
            var planFeatures = await _PlanBLL.GetPlanFeaturesAsync(sub.PlanId, login, ct).ConfigureAwait(false);
            enabledFeatureCodes = planFeatures
                .Where(f => f.IsEnabled != 0)
                .Select(f => f.FeatureCode)
                .ToList();
        }

        var deploymentType = await _ClientProvisioningDAL.GetClientDeploymentTypeAsync(clientId, login, ct).ConfigureAwait(false);

        return new ClientEntitlementSnapshotDTO
        {
            ClientId           = clientId,
            SubscriptionStatus = sub?.SubscriptionStatus ?? 0,
            SupportValidTill   = sub?.SupportValidTill ?? DateTime.MinValue,
            GracePeriodDays    = sub?.GracePeriodDays ?? 0,
            DeploymentType     = deploymentType ?? 0, // 0 = SaaS (GB5Shared.Enums.Client.ClientDeploymentType default)
            EnabledFeatureCodes = enabledFeatureCodes
        };
    }
}