// ==========================================================================
//  Squidex Headless CMS
// ==========================================================================
//  Copyright (c) Squidex UG (haftungsbeschraenkt)
//  All rights reserved. Licensed under the MIT license.
// ==========================================================================

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Squidex.Domain.Apps.Core.Contents;
using Squidex.Infrastructure;

namespace Squidex.Domain.Apps.Entities.Contents
{
    public sealed class DefaultWorkflowsValidator : IWorkflowsValidator
    {
        private readonly IAppProvider appProvider;

        public DefaultWorkflowsValidator(IAppProvider appProvider)
        {
            Guard.NotNull(appProvider, nameof(appProvider));

            this.appProvider = appProvider;
        }

        public async Task<IReadOnlyList<string>> ValidateAsync(Guid appId, Workflows workflows)
        {
            Guard.NotNull(workflows, nameof(workflows));

            var errors = new List<string>();

            if (workflows.Values.Count(x => x.SchemaIds.Count == 0) > 1)
            {
                errors.Add("Multiple workflows cover all schemas.");
            }

            var uniqueSchemaIds = workflows.Values.SelectMany(x => x.SchemaIds).Distinct().ToList();

            foreach (var schemaId in uniqueSchemaIds)
            {
                if (workflows.Values.Count(x => x.SchemaIds.Contains(schemaId)) > 1)
                {
                    var schema = await appProvider.GetSchemaAsync(appId, schemaId);

                    if (schema != null)
                    {
                        errors.Add($"The schema `{schema.SchemaDef.Name}` is covered by multiple workflows.");
                    }
                }
            }

            return errors;
        }
    }
}