// Copyright (c) .NET Foundation. All rights reserved.
// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.

using System;
using System.Diagnostics;
using System.IO;
using System.Threading;
using Microsoft.Extensions.Logging;
using Microsoft.AspNet.Server.Testing.Common;

namespace Microsoft.AspNet.Server.Testing
{
    /// <summary>
    /// Deployer for WebListener and Kestrel.
    /// </summary>
    public class SelfHostDeployer : ApplicationDeployer
    {
        private Process _hostProcess;

        public SelfHostDeployer(DeploymentParameters deploymentParameters, ILogger logger)
            : base(deploymentParameters, logger)
        {
        }

        public override DeploymentResult Deploy()
        {
            // Start timer
            StartTimer();

            PickRuntime();

            if (DeploymentParameters.PublishApplicationBeforeDeployment)
            {
                DnuPublish();
            }

            var uri = TestUriHelper.BuildTestUri(DeploymentParameters.ApplicationBaseUriHint);
            // Launch the host process.
            var hostExitToken = StartSelfHost(uri);

            return new DeploymentResult
            {
                WebRootLocation = DeploymentParameters.ApplicationPath,
                DeploymentParameters = DeploymentParameters,
                ApplicationBaseUri = uri.ToString(),
                HostShutdownToken = hostExitToken
            };
        }

        private CancellationToken StartSelfHost(Uri uri)
        {
            var commandName = DeploymentParameters.Command;
            if (string.IsNullOrEmpty(commandName))
            {
                commandName = "run";
            }

            var dnxPath = Path.Combine(TargetRuntimeBinPath, DnxCommandName);
            var dnxArgs = $"-p \"{DeploymentParameters.ApplicationPath}\" {commandName} " +
                          $"--server.urls {uri} " +
                          $"--server {(DeploymentParameters.ServerType == ServerType.WebListener ? "Microsoft.AspNet.Server.WebListener" : "Microsoft.AspNet.Server.Kestrel")}";

            Logger.LogInformation($"Executing {dnxPath} {dnxArgs}");

            var startInfo = new ProcessStartInfo
            {
                FileName = dnxPath,
                Arguments = dnxArgs,
                UseShellExecute = false,
                CreateNoWindow = true,
                RedirectStandardError = true,
                RedirectStandardOutput = true,
                // Trying a work around for https://github.com/aspnet/Hosting/issues/140.
                RedirectStandardInput = true
            };

            AddEnvironmentVariablesToProcess(startInfo);

            _hostProcess = new Process() { StartInfo = startInfo };
            _hostProcess.ErrorDataReceived += (sender, dataArgs) => { Logger.LogError(dataArgs.Data ?? string.Empty); };
            _hostProcess.OutputDataReceived += (sender, dataArgs) => { Logger.LogInformation(dataArgs.Data ?? string.Empty); };
            _hostProcess.EnableRaisingEvents = true;
            var hostExitTokenSource = new CancellationTokenSource();
            _hostProcess.Exited += (sender, e) =>
            {
                TriggerHostShutdown(hostExitTokenSource);
            };
            _hostProcess.Start();
            _hostProcess.BeginErrorReadLine();
            _hostProcess.BeginOutputReadLine();

            if (_hostProcess.HasExited)
            {
                Logger.LogError("Host process {processName} exited with code {exitCode} or failed to start.", startInfo.FileName, _hostProcess.ExitCode);
                throw new Exception("Failed to start host");
            }

            Logger.LogInformation("Started {fileName}. Process Id : {processId}", startInfo.FileName, _hostProcess.Id);
            return hostExitTokenSource.Token;
        }

        public override void Dispose()
        {
            ShutDownIfAnyHostProcess(_hostProcess);

            if (DeploymentParameters.PublishApplicationBeforeDeployment)
            {
                CleanPublishedOutput();
            }

            InvokeUserApplicationCleanup();

            StopTimer();
        }
    }
}