// Copyright (c) Microsoft Corporation.
// Licensed under the MIT License.

using System;
using System.Collections.Generic;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.Extensions.Logging.Abstractions;
using Microsoft.PowerShell.EditorServices.Hosting;
using Microsoft.PowerShell.EditorServices.Services.PowerShell.Console;
using Microsoft.PowerShell.EditorServices.Services.PowerShell.Execution;
using Microsoft.PowerShell.EditorServices.Services.PowerShell.Host;
using Microsoft.PowerShell.EditorServices.Services.PowerShell.Utility;
using Microsoft.PowerShell.EditorServices.Test;
using Xunit;

namespace PowerShellEditorServices.Test.Session
{
    using System.Management.Automation;
    using System.Management.Automation.Runspaces;

    [Trait("Category", "PsesInternalHost")]
    public class PsesInternalHostTests : IAsyncLifetime
    {
        private PsesInternalHost psesHost;

        public async Task InitializeAsync() => psesHost = await PsesHostFactory.Create(NullLoggerFactory.Instance);

        public async Task DisposeAsync() => await psesHost.StopAsync();

        [Fact]
        public async Task CanExecutePSCommand()
        {
            Assert.True(psesHost.IsRunning);
            PSCommand command = new PSCommand().AddScript("$a = \"foo\"; $a");
            Task<IReadOnlyList<string>> task = psesHost.ExecutePSCommandAsync<string>(command, CancellationToken.None);
            IReadOnlyList<string> result = await task;
            Assert.Equal("foo", result[0]);
        }

        [Fact] // https://github.com/PowerShell/vscode-powershell/issues/3677
        public async Task CanHandleThrow()
        {
            await psesHost.ExecutePSCommandAsync(
                new PSCommand().AddScript("throw"),
                CancellationToken.None,
                new PowerShellExecutionOptions { ThrowOnError = false });
        }

        [Fact]
        public async Task CanQueueParallelPSCommands()
        {
            // Concurrently initiate 4 requests in the session.
            Task taskOne = psesHost.ExecutePSCommandAsync(
                new PSCommand().AddScript("$x = 100"),
                CancellationToken.None);

            Task taskTwo = psesHost.ExecutePSCommandAsync(
                new PSCommand().AddScript("$x += 200"),
                CancellationToken.None);

            Task taskThree = psesHost.ExecutePSCommandAsync(
                new PSCommand().AddScript("$x = $x / 100"),
                CancellationToken.None);

            Task<IReadOnlyList<int>> resultTask = psesHost.ExecutePSCommandAsync<int>(
                new PSCommand().AddScript("$x"),
                CancellationToken.None);

            // Wait for all of the executes to complete.
            await Task.WhenAll(taskOne, taskTwo, taskThree, resultTask);

            // Sanity checks
            Assert.Equal(RunspaceState.Opened, psesHost.Runspace.RunspaceStateInfo.State);

            // 100 + 200 = 300, then divided by 100 is 3.  We are ensuring that
            // the commands were executed in the sequence they were called.
            Assert.Equal(3, (await resultTask)[0]);
        }

        [Fact]
        public async Task CanCancelExecutionWithToken()
        {
            using CancellationTokenSource cancellationSource = new(millisecondsDelay: 1000);
            await Assert.ThrowsAsync<TaskCanceledException>(() =>
            {
                return psesHost.ExecutePSCommandAsync(
                    new PSCommand().AddScript("Start-Sleep 10"),
                    cancellationSource.Token);
            });
        }

        [Fact]
        [System.Diagnostics.CodeAnalysis.SuppressMessage("Usage", "VSTHRD003:Avoid awaiting foreign Tasks", Justification = "Explicitly checking task cancellation status.")]
        public async Task CanCancelExecutionWithMethod()
        {
            Task executeTask = psesHost.ExecutePSCommandAsync(
                new PSCommand().AddScript("Start-Sleep 10"),
                CancellationToken.None);

            // Cancel the task after 1 second in another thread.
            Task.Run(() => { Thread.Sleep(1000); psesHost.CancelCurrentTask(); });
            await Assert.ThrowsAsync<TaskCanceledException>(() => executeTask);
            Assert.True(executeTask.IsCanceled);
        }

        [Fact]
        public async Task CanHandleNoProfiles()
        {
            // Call LoadProfiles with profile paths that won't exist, and assert that it does not
            // throw PSInvalidOperationException (which it previously did when it tried to invoke an
            // empty command).
            ProfilePathInfo emptyProfilePaths = new("", "", "", "");
            await psesHost.ExecuteDelegateAsync(
                "LoadProfiles",
                executionOptions: null,
                (pwsh, _) =>
                {
                    pwsh.LoadProfiles(emptyProfilePaths);
                    Assert.Empty(pwsh.Commands.Commands);
                },
                CancellationToken.None);
        }

        // NOTE: Tests where we call functions that use PowerShell runspaces are slightly more
        // complicated than one would expect because we explicitly need the methods to run on the
        // pipeline thread, otherwise Windows complains about the the thread's apartment state not
        // matching. Hence we use a delegate where it looks like we could just call the method.

        [Fact]
        public async Task CanHandleBrokenPrompt()
        {
            _ = await Assert.ThrowsAsync<RuntimeException>(() =>
            {
                return psesHost.ExecutePSCommandAsync(
                    new PSCommand().AddScript("function prompt { throw }; prompt"),
                    CancellationToken.None);
            });

            string prompt = await psesHost.ExecuteDelegateAsync(
                nameof(psesHost.GetPrompt),
                executionOptions: null,
                (_, _) => psesHost.GetPrompt(CancellationToken.None),
                CancellationToken.None);

            Assert.Equal(PsesInternalHost.DefaultPrompt, prompt);
        }

        [Fact]
        public async Task CanHandleUndefinedPrompt()
        {
            Assert.Empty(await psesHost.ExecutePSCommandAsync<PSObject>(
                new PSCommand().AddScript("Remove-Item function:prompt; Get-Item function:prompt -ErrorAction Ignore"),
                CancellationToken.None));

            string prompt = await psesHost.ExecuteDelegateAsync(
                nameof(psesHost.GetPrompt),
                executionOptions: null,
                (_, _) => psesHost.GetPrompt(CancellationToken.None),
                CancellationToken.None);

            Assert.Equal(PsesInternalHost.DefaultPrompt, prompt);
        }

        [Fact]
        public async Task CanRunOnIdleTask()
        {
            IReadOnlyList<PSObject> task = await psesHost.ExecutePSCommandAsync<PSObject>(
                new PSCommand().AddScript("$handled = $false; Register-EngineEvent -SourceIdentifier PowerShell.OnIdle -MaxTriggerCount 1 -Action { $global:handled = $true }"),
                CancellationToken.None);

            IReadOnlyList<bool> handled = await psesHost.ExecutePSCommandAsync<bool>(
                new PSCommand().AddScript("$handled"),
                CancellationToken.None);

            Assert.Collection(handled, Assert.False);

            await psesHost.ExecuteDelegateAsync(
                nameof(psesHost.OnPowerShellIdle),
                executionOptions: null,
                (_, _) => psesHost.OnPowerShellIdle(CancellationToken.None),
                CancellationToken.None);

            // TODO: Why is this racy?
            Thread.Sleep(2000);

            handled = await psesHost.ExecutePSCommandAsync<bool>(
                new PSCommand().AddScript("$handled"),
                CancellationToken.None);

            Assert.Collection(handled, Assert.True);
        }

        [Fact]
        public async Task CanLoadPSReadLine()
        {
            Assert.True(await psesHost.ExecuteDelegateAsync(
                nameof(psesHost.TryLoadPSReadLine),
                executionOptions: null,
                (pwsh, _) => psesHost.TryLoadPSReadLine(
                    pwsh,
                    (EngineIntrinsics)pwsh.Runspace.SessionStateProxy.GetVariable("ExecutionContext"),
                    out IReadLine readLine),
                CancellationToken.None));
        }

        // This test asserts that we do not mess up the console encoding, which leads to native
        // commands receiving piped input failing.
        [Fact]
        public async Task ExecutesNativeCommandsCorrectly()
        {
            await psesHost.ExecutePSCommandAsync(
                new PSCommand().AddScript("\"protocol=https`nhost=myhost.com`nusername=john`npassword=doe`n`n\" | git.exe credential approve; if ($LastExitCode) { throw }"),
                CancellationToken.None);
        }

        [Theory]
        [InlineData("")] // Regression test for "unset" path.
        [InlineData(@"C:\Some\Bad\Directory")] // Non-existent directory.
        [InlineData("testhost.dll")] // Existent file.
        public async Task CanHandleBadInitialWorkingDirectory(string path)
        {
            string cwd = Environment.CurrentDirectory;
            await psesHost.SetInitialWorkingDirectoryAsync(path, CancellationToken.None);

            IReadOnlyList<string> getLocation = await psesHost.ExecutePSCommandAsync<string>(
                new PSCommand().AddCommand("Get-Location"),
                CancellationToken.None);
            Assert.Collection(getLocation, (d) => Assert.Equal(cwd, d, ignoreCase: true));
        }
    }

    [Trait("Category", "PsesInternalHost")]
    public class PsesInternalHostWithProfileTests : IAsyncLifetime
    {
        private PsesInternalHost psesHost;

        public async Task InitializeAsync() => psesHost = await PsesHostFactory.Create(NullLoggerFactory.Instance, loadProfiles: true);

        public async Task DisposeAsync() => await psesHost.StopAsync();

        [Fact]
        public async Task CanResolveAndLoadProfilesForHostId()
        {
            // Ensure that the $PROFILE variable is a string with the value of CurrentUserCurrentHost.
            IReadOnlyList<string> profileVariable = await psesHost.ExecutePSCommandAsync<string>(
                new PSCommand().AddScript("$PROFILE"),
                CancellationToken.None);

            Assert.Collection(profileVariable,
                (p) => Assert.Equal(PsesHostFactory.TestProfilePaths.CurrentUserCurrentHost, p));

            // Ensure that all the profile paths are set in the correct note properties.
            IReadOnlyList<string> profileProperties = await psesHost.ExecutePSCommandAsync<string>(
                new PSCommand().AddScript("$PROFILE | Get-Member -Type NoteProperty"),
                CancellationToken.None);

            Assert.Collection(profileProperties,
                (p) => Assert.Equal($"string AllUsersAllHosts={PsesHostFactory.TestProfilePaths.AllUsersAllHosts}", p, ignoreCase: true),
                (p) => Assert.Equal($"string AllUsersCurrentHost={PsesHostFactory.TestProfilePaths.AllUsersCurrentHost}", p, ignoreCase: true),
                (p) => Assert.Equal($"string CurrentUserAllHosts={PsesHostFactory.TestProfilePaths.CurrentUserAllHosts}", p, ignoreCase: true),
                (p) => Assert.Equal($"string CurrentUserCurrentHost={PsesHostFactory.TestProfilePaths.CurrentUserCurrentHost}", p, ignoreCase: true));

            // Ensure that the profile was loaded. The profile also checks that $PROFILE was defined.
            IReadOnlyList<bool> profileLoaded = await psesHost.ExecutePSCommandAsync<bool>(
                new PSCommand().AddScript("Assert-ProfileLoaded"),
                CancellationToken.None);

            Assert.Collection(profileLoaded, Assert.True);
        }

        // This test specifically relies on a handler registered in the test profile, and on the
        // test host loading the profiles during startup, that way the pipeline timing is
        // consistent.
        [Fact]
        public async Task CanRunOnIdleInProfileTask()
        {
            await psesHost.ExecuteDelegateAsync(
                nameof(psesHost.OnPowerShellIdle),
                executionOptions: null,
                (_, _) => psesHost.OnPowerShellIdle(CancellationToken.None),
                CancellationToken.None);

            // TODO: Why is this racy?
            Thread.Sleep(2000);

            IReadOnlyList<bool> handled = await psesHost.ExecutePSCommandAsync<bool>(
                new PSCommand().AddScript("$handledInProfile"),
                CancellationToken.None);

            Assert.Collection(handled, Assert.True);
        }
    }
}