using Elsa.Extensions;
using Elsa.Http.Contracts;
using Elsa.Http.Models;
using Microsoft.AspNetCore.Authorization;

namespace Elsa.Http.Handlers;

public class AuthenticationBasedHttpEndpointAuthorizationHandler : IHttpEndpointAuthorizationHandler
{
    private readonly IAuthorizationService _authorizationService;
    public AuthenticationBasedHttpEndpointAuthorizationHandler(IAuthorizationService authorizationService) => _authorizationService = authorizationService;

    public async ValueTask<bool> AuthorizeAsync(AuthorizeHttpEndpointContext context)
    {
        var httpContext = context.HttpContext;
        var user = httpContext.User;
        var identity = user.Identity;

        if (identity == null)
            return false;
            
        if (identity.IsAuthenticated == false)
            return false;
            
        var httpEndpoint = context.Activity;
        var expressionExecutionContext = context.ExpressionExecutionContext;
        var policyName = httpEndpoint.Policy.TryGet(expressionExecutionContext);

        if (string.IsNullOrWhiteSpace(policyName))
            return identity.IsAuthenticated;

        var resource = new HttpWorkflowResource(expressionExecutionContext, httpEndpoint, context.WorkflowInstanceId);
        var authorizationResult = await _authorizationService.AuthorizeAsync(user, resource, policyName);
        return authorizationResult.Succeeded;
    }
}