using BuildingBlock.Identity.Contracts.Conventions;
using Thalos.DAL.Contracts;

namespace Thalos.DAL.Providers;

/// <summary>
/// Internal JWT provider implementation for identity user reads.
/// </summary>
public sealed class InternalJwtUserDataProvider : IUserDataProvider
{
    /// <inheritdoc />
    public Task<IdentityUserRecord?> ReadUserAsync(
        IdentityUserLookupRequest request,
        CancellationToken cancellationToken = default)
    {
        if (request.SubjectId.StartsWith("missing-", StringComparison.OrdinalIgnoreCase))
        {
            return Task.FromResult<IdentityUserRecord?>(null);
        }

        var record = new IdentityUserRecord(
            request.Envelope,
            request.SubjectId,
            request.TenantId,
            "active",
            $"{request.SubjectId}:{request.TenantId}:token",
            1800,
            true);

        return Task.FromResult<IdentityUserRecord?>(record);
    }
}

/// <summary>
/// Azure AD provider implementation for identity user reads.
/// </summary>
public sealed class AzureAdUserDataProvider : IUserDataProvider
{
    /// <inheritdoc />
    public Task<IdentityUserRecord?> ReadUserAsync(
        IdentityUserLookupRequest request,
        CancellationToken cancellationToken = default)
    {
        var subjectId = ResolveSubjectId(request, "azure-sub");
        if (string.IsNullOrWhiteSpace(subjectId))
        {
            return Task.FromResult<IdentityUserRecord?>(null);
        }

        var record = new IdentityUserRecord(
            request.Envelope,
            subjectId,
            request.TenantId,
            "active",
            $"azure:{subjectId}:{request.TenantId}:token",
            3600,
            true);

        return Task.FromResult<IdentityUserRecord?>(record);
    }

    private static string ResolveSubjectId(IdentityUserLookupRequest request, string prefix)
    {
        if (!string.IsNullOrWhiteSpace(request.SubjectId))
        {
            return request.SubjectId;
        }

        if (string.IsNullOrWhiteSpace(request.ExternalToken))
        {
            return string.Empty;
        }

        return $"{prefix}-{Math.Abs(request.ExternalToken.GetHashCode(StringComparison.Ordinal))}";
    }
}

/// <summary>
/// Google provider implementation for identity user reads.
/// </summary>
public sealed class GoogleUserDataProvider : IUserDataProvider
{
    /// <inheritdoc />
    public Task<IdentityUserRecord?> ReadUserAsync(
        IdentityUserLookupRequest request,
        CancellationToken cancellationToken = default)
    {
        var subjectId = ResolveSubjectId(request, "google-sub");
        if (string.IsNullOrWhiteSpace(subjectId))
        {
            return Task.FromResult<IdentityUserRecord?>(null);
        }

        var record = new IdentityUserRecord(
            request.Envelope,
            subjectId,
            request.TenantId,
            "active",
            $"google:{subjectId}:{request.TenantId}:token",
            3000,
            true);

        return Task.FromResult<IdentityUserRecord?>(record);
    }

    private static string ResolveSubjectId(IdentityUserLookupRequest request, string prefix)
    {
        if (!string.IsNullOrWhiteSpace(request.SubjectId))
        {
            return request.SubjectId;
        }

        if (string.IsNullOrWhiteSpace(request.ExternalToken))
        {
            return string.Empty;
        }

        return $"{prefix}-{Math.Abs(request.ExternalToken.GetHashCode(StringComparison.Ordinal))}";
    }
}

/// <summary>
/// Routes user lookups to the matching provider implementation.
/// </summary>
public sealed class RoutedUserDataProvider(
    InternalJwtUserDataProvider internalJwtProvider,
    AzureAdUserDataProvider azureProvider,
    GoogleUserDataProvider googleProvider) : IUserDataProvider
{
    /// <inheritdoc />
    public Task<IdentityUserRecord?> ReadUserAsync(
        IdentityUserLookupRequest request,
        CancellationToken cancellationToken = default)
    {
        return request.Provider switch
        {
            IdentityAuthProvider.InternalJwt => internalJwtProvider.ReadUserAsync(request, cancellationToken),
            IdentityAuthProvider.AzureAd => azureProvider.ReadUserAsync(request, cancellationToken),
            IdentityAuthProvider.Google => googleProvider.ReadUserAsync(request, cancellationToken),
            _ => Task.FromResult<IdentityUserRecord?>(null)
        };
    }
}