using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Xml.Linq;
using Umbraco.Cms.Core.Events;
using Umbraco.Cms.Core.Models;
using Umbraco.Cms.Core.Models.Packaging;
using Umbraco.Cms.Core.Notifications;
using Umbraco.Cms.Core.Packaging;

namespace Umbraco.Cms.Core.Services.Implement
{
    /// <summary>
    /// Represents the Packaging Service, which provides import/export functionality for the Core models of the API
    /// using xml representation. This is primarily used by the Package functionality.
    /// </summary>
    public class PackagingService : IPackagingService
    {
        private readonly IPackageInstallation _packageInstallation;
        private readonly IEventAggregator _eventAggregator;
        private readonly IAuditService _auditService;
        private readonly ICreatedPackagesRepository _createdPackages;

        public PackagingService(
            IAuditService auditService,
            ICreatedPackagesRepository createdPackages,
            IPackageInstallation packageInstallation,
            IEventAggregator eventAggregator)
        {
            _auditService = auditService;
            _createdPackages = createdPackages;
            _packageInstallation = packageInstallation;
            _eventAggregator = eventAggregator;
        }

        #region Installation

        public CompiledPackage GetCompiledPackageInfo(XDocument xml) => _packageInstallation.ReadPackage(xml);

        public InstallationSummary InstallCompiledPackageData(XDocument packageXml, int userId = Constants.Security.SuperUserId)
        {
            CompiledPackage compiledPackage = GetCompiledPackageInfo(packageXml);

            if (compiledPackage == null)
            {
                throw new InvalidOperationException("Could not read the package file " + packageXml);
            }

            // Trigger the Importing Package Notification and stop execution if event/user is cancelling it
            var importingPackageNotification = new ImportingPackageNotification(compiledPackage.Name);
            if (_eventAggregator.PublishCancelable(importingPackageNotification))
            {
                return new InstallationSummary(compiledPackage.Name);
            }

            var summary = _packageInstallation.InstallPackageData(compiledPackage, userId, out _);

            _auditService.Add(AuditType.PackagerInstall, userId, -1, "Package", $"Package data installed for package '{compiledPackage.Name}'.");

            // trigger the ImportedPackage event
            _eventAggregator.Publish(new ImportedPackageNotification(summary).WithStateFrom(importingPackageNotification));

            return summary;
        }

        public InstallationSummary InstallCompiledPackageData(FileInfo packageXmlFile, int userId = Constants.Security.SuperUserId)
        {
            XDocument xml;
            using (StreamReader streamReader = System.IO.File.OpenText(packageXmlFile.FullName))
            {
                xml = XDocument.Load(streamReader);                
            }
            return InstallCompiledPackageData(xml, userId);
        }

        #endregion

        #region Created/Installed Package Repositories

        public void DeleteCreatedPackage(int id, int userId = Cms.Core.Constants.Security.SuperUserId)
        {
            var package = GetCreatedPackageById(id);
            if (package == null) return;

            _auditService.Add(AuditType.PackagerUninstall, userId, -1, "Package", $"Created package '{package.Name}' deleted. Package id: {package.Id}");
            _createdPackages.Delete(id);
        }

        public IEnumerable<PackageDefinition> GetAllCreatedPackages() => _createdPackages.GetAll();

        public PackageDefinition GetCreatedPackageById(int id) => _createdPackages.GetById(id);

        public bool SaveCreatedPackage(PackageDefinition definition) => _createdPackages.SavePackage(definition);

        public string ExportCreatedPackage(PackageDefinition definition) => _createdPackages.ExportPackage(definition);


        // TODO: Implement
        public IEnumerable<PackageDefinition> GetAllInstalledPackages() => Enumerable.Empty<PackageDefinition>();
        
        #endregion
    }
}