// Copyright (c) Contributors to the Apptainer project, established as
//   Apptainer a Series of LF Projects LLC.
//   For website terms of use, trademark policy, privacy policy and other
//   project policies see https://lfprojects.org/policies
// 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 (
	"bufio"
	"bytes"
	"fmt"
	"os"
	"os/user"
	"path/filepath"
	"strconv"
	"strings"
	"syscall"
	"testing"
	"time"

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

// 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
	withEnv []string
}

// 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.RunApptainer(
		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 that instance run command executes the runscript
func (c *ctx) testInstanceRun(t *testing.T) {
	const instanceName = "testtrue"

	args := []string{c.env.ImagePath, instanceName, "true"}

	// Start the instance.
	c.env.RunApptainer(
		t,
		e2e.WithProfile(c.profile),
		e2e.WithCommand("instance run"),
		e2e.WithArgs(args...),
		e2e.PostRun(func(t *testing.T) {
			if t.Failed() {
				return
			}
			// read the log file to see if runscript was used. (It should record
			// the text "Running command: true")
			d, err := os.UserHomeDir()
			if err != nil {
				t.Fatal(err)
			}
			h, err := os.Hostname()
			if err != nil {
				t.Fatal(err)
			}
			u, err := user.Current()
			if err != nil {
				t.Fatal(err)
			}
			ilog := filepath.Join(d, ".apptainer", "instances", "logs", h, u.Username, instanceName+".out")
			b, err := os.ReadFile(ilog)
			if err != nil {
				t.Fatal(err)
			}
			s := string(b)
			echo(t, instanceStartPort)
			c.stopInstance(t, instanceName)
			if !strings.Contains(s, "Running command: true") {
				t.Fatal()
			}
		}),
		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.RunApptainer(
			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, false)
	}
}

// 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"
	cmdList := [2]string{"instance start", "instance run"}
	fileContents := []byte("world")

	// Create a temporary directory to serve as a home directory.
	dir, err := os.MkdirTemp(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 = os.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 and Run an instance with the temporary directory as the home
	// directory.
	for _, cmd := range cmdList {
		c.env.RunApptainer(
			t,
			e2e.WithProfile(c.profile),
			e2e.WithCommand(cmd),
			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)
				}

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

				// 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"
	cmdList := [2]string{"instance start", "instance run"}

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

	// Start and Run the instance.
	for _, cmd := range cmdList {
		c.env.RunApptainer(
			t,
			e2e.WithProfile(c.profile),
			e2e.WithCommand(cmd),
			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) {
	e2e.EnsureORASImage(t, c.env)
	name := "test_from_uri"
	args := []string{c.env.OrasTestImage, name}
	cmdList := [2]string{"instance start", "instance run"}
	for _, cmd := range cmdList {
		c.env.RunApptainer(
			t,
			e2e.WithProfile(c.profile),
			e2e.WithCommand(cmd),
			e2e.WithArgs(args...),
			e2e.PostRun(func(t *testing.T) {
				if t.Failed() {
					return
				}
				c.execInstance(t, name, "id")
				c.stopInstance(t, 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) {
	cmdList := [2]string{"instance start", "instance run"}

	for _, cmd := range cmdList {
		// 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 := os.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.RunApptainer(
				t,
				e2e.WithProfile(c.profile),
				e2e.WithCommand(cmd),
				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.RunApptainer(
				t,
				e2e.WithProfile(c.profile),
				e2e.WithCommand(cmd),
				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.RunApptainer(
			t,
			e2e.WithProfile(c.profile),
			e2e.WithCommand(cmd),
			e2e.WithArgs("--pid-file", pidfile, c.env.ImagePath, instanceName),
			e2e.PostRun(postFn),
			e2e.ExpectExit(0),
		)
	}
}

// Test instances when using an alternate configdir
func (c *ctx) testInstanceWithConfigDir(t *testing.T) {
	dir, err := os.MkdirTemp(c.env.TestDir, "InstanceWithConfigDir")
	if err != nil {
		t.Fatalf("Failed to create temporary directory: %v", err)
	}
	defer os.RemoveAll(dir)

	c.withEnv = append(os.Environ(), "APPTAINER_CONFIGDIR="+dir)
	defer func() {
		c.withEnv = []string{}
	}()

	name := "movedConfig"
	c.env.RunApptainer(
		t,
		e2e.WithProfile(c.profile),
		e2e.WithCommand("instance start"),
		e2e.WithArgs(c.env.ImagePath, name),
		e2e.WithEnv(c.withEnv),
		e2e.ExpectExit(0),
	)

	c.expectInstance(t, name, 1, false)
	c.execInstance(t, name, "id")
	c.stopInstance(t, name)

	e2e.Privileged(func(t *testing.T) {
		if _, err := os.Stat(dir + "/instances/app"); err != nil {
			t.Fatalf("failed %v", err)
		}
	})(t)
}

// testShareNSMopde will test --sharens flag
func (c *ctx) testShareNSMode(t *testing.T) {
	dir, err := os.MkdirTemp(c.env.TestDir, "InstanceShareNS")
	if err != nil {
		t.Fatalf("Failed to create temporary directory: %v", err)
	}
	defer os.RemoveAll(dir)

	file := fmt.Sprintf("%s/file", dir)
	f, err := os.Create(file)
	if err != nil {
		t.Fatalf("failed to create file, this is unexpected, err: %v", err)
	}
	f.Close()

	insNumber := 2
	for i := 0; i < insNumber; i++ {
		go c.env.RunApptainer(
			t,
			e2e.WithProfile(c.profile),
			e2e.WithCommand("exec"),
			e2e.WithArgs("--bind", fmt.Sprintf("%s:/canary/file", file), "--sharens", c.env.ImagePath, "sh", "-c", "echo 0 >> /canary/file; sleep 1"),
			e2e.ExpectExit(0),
		)
	}

	// waiting enough time for the file written
	time.Sleep(2 * time.Second)

	f, err = os.Open(file)
	if err != nil {
		t.Fatalf("failed to open file: %v, this is unexpected", err)
	}
	defer f.Close()

	scanner := bufio.NewScanner(f)
	scanner.Split(bufio.ScanLines)

	var count int
	for scanner.Scan() {
		count++
	}

	if err := scanner.Err(); err != nil {
		t.Fatalf("having issue while scanning file: %s, err: %v", file, err)
	}

	if count != insNumber {
		t.Fatalf("should have %d lines, but actually is %d", insNumber, count)
	}
}

// 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},
				{"InstanceRun", c.testInstanceRun},
				{"StopAll", c.testStopAll},
				{"GhostInstance", c.testGhostInstance},
				{"CheckpointInstance", c.testCheckpointInstance},
				{"InstanceWithConfigDir", c.testInstanceWithConfigDir},
				{"ShareNSMode", c.testShareNSMode},
				{"issue 2189", c.issue2189},
			}

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

			for _, profile := range profiles {
				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/apptainer/singularity/issues/4836
	}
}
