using DigitalData.MessagingService.Application.Common.Interfaces;
using DigitalData.MessagingService.Domain.Entities;
using DigitalData.MessagingService.Domain.Enums;
using Microsoft.Extensions.DependencyInjection;

namespace DigitalData.MessagingService.Infrastructure.Services;

/// <summary>
/// Routes OAuth2 token requests to the correct provider-specific implementation
/// based on <see cref="EmailAccount.OAuth2Provider"/>.
/// Registered as the single <see cref="IOAuth2TokenService"/> in DI — all other
/// services depend on this dispatcher rather than on a concrete provider directly.
/// </summary>
public class OAuth2TokenServiceDispatcher(IServiceProvider ServiceProvider) : IOAuth2TokenService
{
    public Task<string> GetAccessTokenAsync(EmailAccount account, CancellationToken cancellationToken = default)
    {
        var service = account.OAuth2Provider switch
        {
            OAuth2Provider.Microsoft => ServiceProvider.GetRequiredService<MicrosoftOAuth2TokenService>(),
            OAuth2Provider.Google    => (IOAuth2TokenService)ServiceProvider.GetRequiredService<GoogleOAuth2TokenService>(),

            OAuth2Provider.None => throw new InvalidOperationException(
                $"Account '{account.Username}' (Id: {account.Id}) has OAuth2Provider = None. " +
                "Set UseOAuth2 = false or configure a valid OAuth2Provider."),

            _ => throw new NotSupportedException(
                $"OAuth2Provider '{account.OAuth2Provider}' is not supported. " +
                $"Supported providers: {string.Join(", ", Enum.GetNames<OAuth2Provider>())}")
        };

        return service.GetAccessTokenAsync(account, cancellationToken);
    }
}