// Copyright (c) 2019-2022, Sylabs Inc. All rights reserved.
// This software is licensed under a 3-clause BSD license. Please consult the
// LICENSE.md file distributed with the sources of this project regarding your
// rights to use or distribute this software.

package instance

import (
	"bytes"
	"io/ioutil"
	"os"
	"path/filepath"
	"strconv"
	"strings"
	"syscall"
	"testing"

	"github.com/google/uuid"
	"github.com/pkg/errors"
	"github.com/sylabs/singularity/e2e/internal/e2e"
	"github.com/sylabs/singularity/e2e/internal/testhelper"
	"github.com/sylabs/singularity/pkg/util/fs/proc"
)

// randomName generates a random name based on a UUID.
func randomName(t *testing.T) string {
	t.Helper()

	id, err := uuid.NewRandom()
	if err != nil {
		t.Fatal(err)
	}
	return id.String()
}

type ctx struct {
	env     e2e.TestEnv
	profile e2e.Profile
}

// Test that a basic echo server instance can be started, communicated with,
// and stopped.
func (c *ctx) testBasicEchoServer(t *testing.T) {
	const instanceName = "echo1"

	args := []string{c.env.ImagePath, instanceName, strconv.Itoa(instanceStartPort)}

	// Start the instance.
	c.env.RunSingularity(
		t,
		e2e.WithProfile(c.profile),
		e2e.WithCommand("instance start"),
		e2e.WithArgs(args...),
		e2e.PostRun(func(t *testing.T) {
			if t.Failed() {
				return
			}
			// Try to contact the instance.
			echo(t, instanceStartPort)
			c.stopInstance(t, instanceName)
		}),
		e2e.ExpectExit(0),
	)
}

// Test creating many instances, but don't stop them.
func (c *ctx) testCreateManyInstances(t *testing.T) {
	const n = 10

	// Start n instances.
	for i := 0; i < n; i++ {
		port := instanceStartPort + i
		instanceName := "echo" + strconv.Itoa(i+1)

		c.env.RunSingularity(
			t,
			e2e.WithProfile(c.profile),
			e2e.WithCommand("instance start"),
			e2e.WithArgs(c.env.ImagePath, instanceName, strconv.Itoa(port)),
			e2e.PostRun(func(t *testing.T) {
				echo(t, port)
			}),
			e2e.ExpectExit(0),
		)

		c.expectInstance(t, instanceName, 1)
	}
}

// Test stopping all running instances.
func (c *ctx) testStopAll(t *testing.T) {
	c.stopInstance(t, "", "--all")
}

// Test basic options like mounting a custom home directory, changing the
// hostname, etc.
func (c *ctx) testBasicOptions(t *testing.T) {
	const fileName = "hello"
	const instanceName = "testbasic"
	const testHostname = "echoserver99"
	fileContents := []byte("world")

	// Create a temporary directory to serve as a home directory.
	dir, err := ioutil.TempDir(c.env.TestDir, "TestInstance")
	if err != nil {
		t.Fatalf("Failed to create temporary directory: %v", err)
	}
	defer os.RemoveAll(dir)

	// Create and populate a temporary file.
	tempFile := filepath.Join(dir, fileName)
	err = ioutil.WriteFile(tempFile, fileContents, 0o644)
	err = errors.Wrapf(err, "creating temporary test file %s", tempFile)
	if err != nil {
		t.Fatalf("Failed to create file: %+v", err)
	}

	// Start an instance with the temporary directory as the home directory.
	c.env.RunSingularity(
		t,
		e2e.WithProfile(c.profile),
		e2e.WithCommand("instance start"),
		e2e.WithArgs(
			"-H", dir+":/home/temp",
			"--hostname", testHostname,
			"-e",
			c.env.ImagePath,
			instanceName,
			strconv.Itoa(instanceStartPort),
		),
		e2e.PostRun(func(t *testing.T) {
			if t.Failed() {
				return
			}

			// Verify we can see the file's contents from within the container.
			stdout, _, success := c.execInstance(t, instanceName, "cat", "/home/temp/"+fileName)
			if success && !bytes.Equal(fileContents, []byte(stdout)) {
				t.Errorf("File contents were %s, but expected %s", stdout, string(fileContents))
			}

			// Verify that the hostname has been set correctly.
			stdout, _, success = c.execInstance(t, instanceName, "hostname")
			if success && !bytes.Equal([]byte(testHostname+"\n"), []byte(stdout)) {
				t.Errorf("Hostname is %s, but expected %s", stdout, testHostname)
			}

			// Stop the instance.
			c.stopInstance(t, instanceName)
		}),
		e2e.ExpectExit(0),
	)
}

// Test that contain works.
func (c *ctx) testContain(t *testing.T) {
	const instanceName = "testcontain"
	const fileName = "thegreattestfile"

	// Create a temporary directory to serve as a contain directory.
	dir, err := ioutil.TempDir("", "TestInstance")
	if err != nil {
		t.Fatalf("Failed to create temporary directory: %v", err)
	}
	defer os.RemoveAll(dir)

	// Start the instance.
	c.env.RunSingularity(
		t,
		e2e.WithProfile(c.profile),
		e2e.WithCommand("instance start"),
		e2e.WithArgs(
			"-c",
			"-W", dir,
			c.env.ImagePath,
			instanceName,
			strconv.Itoa(instanceStartPort),
		),
		e2e.PostRun(func(t *testing.T) {
			if t.Failed() {
				return
			}

			// Touch a file within /tmp.
			_, _, success := c.execInstance(t, instanceName, "touch", "/tmp/"+fileName)
			if success {
				// Verify that the touched file exists outside the container.
				if _, err = os.Stat(filepath.Join(dir, "tmp", fileName)); os.IsNotExist(err) {
					t.Errorf("The temp file doesn't exist.")
				}
			}

			// Stop the container.
			c.stopInstance(t, instanceName)
		}),
		e2e.ExpectExit(0),
	)
}

// Test by running directly from URI
func (c *ctx) testInstanceFromURI(t *testing.T) {
	instances := []struct {
		name string
		uri  string
	}{
		{
			name: "test_from_docker",
			uri:  "docker://busybox",
		},
		{
			name: "test_from_library",
			uri:  "library://busybox:1.31.1",
		},
		// TODO(mem): reenable this; disabled while shub is down
		// {
		// 	name: "test_from_shub",
		// 	uri:  "shub://singularityhub/busybox",
		// },
	}

	for _, i := range instances {
		args := []string{i.uri, i.name}
		c.env.RunSingularity(
			t,
			e2e.WithProfile(c.profile),
			e2e.WithCommand("instance start"),
			e2e.WithArgs(args...),
			e2e.PostRun(func(t *testing.T) {
				if t.Failed() {
					return
				}
				c.execInstance(t, i.name, "id")
				c.stopInstance(t, i.name)
			}),
			e2e.ExpectExit(0),
		)
	}
}

// Execute an instance process, kill master process
// and try to start another instance with same name
func (c *ctx) testGhostInstance(t *testing.T) {
	// pick up a random name
	instanceName := randomName(t)
	pidfile := filepath.Join(c.env.TestDir, instanceName)

	postFn := func(t *testing.T) {
		defer os.Remove(pidfile)

		if t.Failed() {
			t.Fatalf("instance %s failed to start correctly", instanceName)
		}

		d, err := ioutil.ReadFile(pidfile)
		if err != nil {
			t.Fatalf("failed to read pid file: %s", err)
		}
		trimmed := strings.TrimSuffix(string(d), "\n")
		pid, err := strconv.ParseInt(trimmed, 10, 32)
		if err != nil {
			t.Fatalf("failed to convert PID %s in %s: %s", trimmed, pidfile, err)
		}
		ppid, err := proc.Getppid(int(pid))
		if err != nil {
			t.Fatalf("failed to get parent process ID for process %d: %s", pid, err)
		}

		// starting same instance twice must return an error
		c.env.RunSingularity(
			t,
			e2e.WithProfile(c.profile),
			e2e.WithCommand("instance start"),
			e2e.WithArgs(c.env.ImagePath, instanceName),
			e2e.ExpectExit(
				255,
				e2e.ExpectErrorf(e2e.ContainMatch, "instance %s already exists", instanceName),
			),
		)

		// kill master process
		if err := syscall.Kill(int(ppid), syscall.SIGKILL); err != nil {
			t.Fatalf("failed to send KILL signal to %d: %s", ppid, err)
		}

		// now check we are deleting ghost instance files correctly
		c.env.RunSingularity(
			t,
			e2e.WithProfile(c.profile),
			e2e.WithCommand("instance start"),
			e2e.WithArgs(c.env.ImagePath, instanceName),
			e2e.PostRun(func(t *testing.T) {
				if t.Failed() {
					return
				}
				c.stopInstance(t, instanceName)
			}),
			e2e.ExpectExit(0),
		)
	}

	c.env.RunSingularity(
		t,
		e2e.WithProfile(c.profile),
		e2e.WithCommand("instance start"),
		e2e.WithArgs("--pid-file", pidfile, c.env.ImagePath, instanceName),
		e2e.PostRun(postFn),
		e2e.ExpectExit(0),
	)
}

// E2ETests is the main func to trigger the test suite
func E2ETests(env e2e.TestEnv) testhelper.Tests {
	c := &ctx{
		env: env,
	}

	return testhelper.Tests{
		"ordered": func(t *testing.T) {
			c := &ctx{
				env:     env,
				profile: e2e.UserProfile,
			}

			e2e.EnsureImage(t, c.env)

			// Define and loop through tests.
			tests := []struct {
				name     string
				function func(*testing.T)
			}{
				{"BasicEchoServer", c.testBasicEchoServer},
				{"BasicOptions", c.testBasicOptions},
				{"Contain", c.testContain},
				{"InstanceFromURI", c.testInstanceFromURI},
				{"CreateManyInstances", c.testCreateManyInstances},
				{"StopAll", c.testStopAll},
				{"GhostInstance", c.testGhostInstance},
			}

			profiles := []e2e.Profile{
				e2e.UserProfile,
				e2e.RootProfile,
			}

			for _, profile := range profiles {
				profile := profile
				t.Run(profile.String(), func(t *testing.T) {
					c.profile = profile
					for _, tt := range tests {
						t.Run(tt.name, tt.function)
					}
				})
			}
		},
		"issue 5033": c.issue5033, // https://github.com/sylabs/singularity/issues/4836
	}
}
