// UntarFiles will extract the contents of tarFile using
// outputFolder as root
func UntarFiles(tarFile io.Reader, outputFolder string) error {
	tr := tar.NewReader(tarFile)
	for {
		hdr, err := tr.Next()
		if err == io.EOF {
			// end of tar archive
			return nil
		}
		if err != nil {
			return fmt.Errorf("failed while reading tar header: %v", err)
		}
		fullPath := filepath.Join(outputFolder, hdr.Name)
		switch hdr.Typeflag {
		case tar.TypeDir:
			if err = os.MkdirAll(fullPath, os.FileMode(hdr.Mode)); err != nil {
				return fmt.Errorf("cannot extract directory %q: %v", fullPath, err)
			}
		case tar.TypeSymlink:
			if err = symlink.New(hdr.Linkname, fullPath); err != nil {
				return fmt.Errorf("cannot extract symlink %q to %q: %v", hdr.Linkname, fullPath, err)
			}
			continue
		case tar.TypeReg, tar.TypeRegA:
			if err = createAndFill(fullPath, hdr.Mode, tr); err != nil {
				return fmt.Errorf("cannot extract file %q: %v", fullPath, err)
			}
		}
	}
	return nil
}

func (s *prereqsSuite) SetUpTest(c *gc.C) {
	s.BaseSuite.SetUpTest(c)
	s.tmpdir = c.MkDir()
	s.testMongodPath = filepath.Join(s.tmpdir, "mongod")

	s.PatchEnvironment("PATH", s.tmpdir)

	s.PatchValue(&mongo.JujuMongodPath, "/somewhere/that/wont/exist")

	os.Setenv("JUJUTEST_LSB_RELEASE_ID", "Ubuntu")
	err := ioutil.WriteFile(filepath.Join(s.tmpdir, "lsb_release"), []byte(lsbrelease), 0777)
	c.Assert(err, jc.ErrorIsNil)

	// symlink $temp/dpkg-query to /bin/true, to
	// simulate package installation query responses.
	pm, err := testing.GetPackageManager()
	c.Assert(err, jc.ErrorIsNil)

	err = symlink.New("/bin/true", filepath.Join(s.tmpdir, pm.PackageQuery))
	c.Assert(err, jc.ErrorIsNil)
	s.PatchValue(&isPackageInstalled, func(pack string) bool {
		pacman, err := manager.NewPackageManager(series.HostSeries())
		c.Assert(err, jc.ErrorIsNil)
		return pacman.IsInstalled(pack)
	})
}

func (*SymlinkSuite) TestReplace(c *gc.C) {
	target, err := symlink.GetLongPathAsString(c.MkDir())
	c.Assert(err, gc.IsNil)
	target_second, err := symlink.GetLongPathAsString(c.MkDir())
	c.Assert(err, gc.IsNil)
	link := filepath.Join(target, "link")

	_, err = os.Stat(target)
	c.Assert(err, gc.IsNil)
	_, err = os.Stat(target_second)
	c.Assert(err, gc.IsNil)

	err = symlink.New(target, link)
	c.Assert(err, gc.IsNil)

	link_target, err := symlink.Read(link)
	c.Assert(err, gc.IsNil)
	c.Assert(link_target, gc.Equals, filepath.FromSlash(target))

	err = symlink.Replace(link, target_second)
	c.Assert(err, gc.IsNil)

	link_target, err = symlink.Read(link)
	c.Assert(err, gc.IsNil)
	c.Assert(link_target, gc.Equals, filepath.FromSlash(target_second))
}

func (s *MachineSuite) TestMachineAgentSymlinkJujuRunExists(c *gc.C) {
	if runtime.GOOS == "windows" {
		// Cannot make symlink to nonexistent file on windows or
		// create a file point a symlink to it then remove it
		c.Skip("Cannot test this on windows")
	}

	stm, _, _ := s.primeAgent(c, state.JobManageModel)
	a := s.newAgent(c, stm)
	defer a.Stop()

	// Pre-create the symlinks, but pointing to the incorrect location.
	links := []string{jujuRun, jujuDumpLogs}
	a.rootDir = c.MkDir()
	for _, link := range links {
		fullLink := utils.EnsureBaseDir(a.rootDir, link)
		c.Assert(os.MkdirAll(filepath.Dir(fullLink), os.FileMode(0755)), jc.ErrorIsNil)
		c.Assert(symlink.New("/nowhere/special", fullLink), jc.ErrorIsNil, gc.Commentf(link))
	}

	// Start the agent and wait for it be running.
	_, done := s.waitForOpenState(c, a)

	// juju-run symlink should have been recreated.
	for _, link := range links {
		fullLink := utils.EnsureBaseDir(a.rootDir, link)
		linkTarget, err := symlink.Read(fullLink)
		c.Assert(err, jc.ErrorIsNil)
		c.Assert(linkTarget, gc.Not(gc.Equals), "/nowhere/special", gc.Commentf(link))
	}

	s.waitStopped(c, state.JobManageModel, a, done)
}

func (s *ToolsSuite) SetUpTest(c *gc.C) {
	s.dataDir = c.MkDir()
	s.toolsDir = tools.SharedToolsDir(s.dataDir, version.Current)
	err := os.MkdirAll(s.toolsDir, 0755)
	c.Assert(err, gc.IsNil)
	err = symlink.New(s.toolsDir, tools.ToolsDir(s.dataDir, "unit-u-123"))
	c.Assert(err, gc.IsNil)
}

func (a *MachineAgent) createJujuRun(dataDir string) error {
	// TODO do not remove the symlink if it already points
	// to the right place.
	if err := os.Remove(jujuRun); err != nil && !os.IsNotExist(err) {
		return err
	}
	jujud := filepath.Join(dataDir, "tools", a.Tag().String(), jujunames.Jujud)
	return symlink.New(jujud, jujuRun)
}

func (s *prereqsSuite) TestJujuLocalPrereq(c *gc.C) {
	err := os.Remove(filepath.Join(s.tmpdir, "dpkg-query"))
	c.Assert(err, gc.IsNil)
	err = symlink.New("/bin/false", filepath.Join(s.tmpdir, "dpkg-query"))
	c.Assert(err, gc.IsNil)

	err = VerifyPrerequisites(instance.LXC)
	c.Assert(err, gc.ErrorMatches, "(.|\n)*juju-local must be installed to enable the local provider(.|\n)*")
	c.Assert(err, gc.ErrorMatches, "(.|\n)*apt-get install juju-local(.|\n)*")
}

func (s *ToolsSuite) SetUpTest(c *gc.C) {
	s.dataDir = c.MkDir()
	s.toolsDir = tools.SharedToolsDir(s.dataDir, version.Binary{
		Number: version.Current,
		Arch:   arch.HostArch(),
		Series: series.HostSeries(),
	})
	err := os.MkdirAll(s.toolsDir, 0755)
	c.Assert(err, jc.ErrorIsNil)
	err = symlink.New(s.toolsDir, tools.ToolsDir(s.dataDir, "unit-u-123"))
	c.Assert(err, jc.ErrorIsNil)
}

func (s *prereqsSuite) TestJujuLocalPrereq(c *gc.C) {

	pm, err := testing.GetPackageManager()
	c.Assert(err, jc.ErrorIsNil)

	err = os.Remove(filepath.Join(s.tmpdir, pm.PackageQuery))
	c.Assert(err, jc.ErrorIsNil)
	err = symlink.New("/bin/false", filepath.Join(s.tmpdir, pm.PackageQuery))
	c.Assert(err, jc.ErrorIsNil)

	err = VerifyPrerequisites(instance.LXC)
	c.Assert(err, gc.ErrorMatches, "(.|\n)*juju-local must be installed to enable the local provider(.|\n)*")
	c.Assert(err, gc.ErrorMatches, "(.|\n)*apt-get install juju-local(.|\n)*")
}

func (s *MachineSuite) TestMachineAgentSymlinkJujuRunExists(c *gc.C) {
	err := symlink.New("/nowhere/special", jujuRun)
	c.Assert(err, gc.IsNil)
	_, err = os.Stat(jujuRun)
	c.Assert(err, jc.Satisfies, os.IsNotExist)
	s.assertJobWithAPI(c, state.JobManageEnviron, func(conf agent.Config, st *api.State) {
		// juju-run should have been recreated
		_, err := os.Stat(jujuRun)
		c.Assert(err, gc.IsNil)
		link, err := symlink.Read(jujuRun)
		c.Assert(err, gc.IsNil)
		c.Assert(link, gc.Not(gc.Equals), "/nowhere/special")
	})
}

func (*SymlinkSuite) TestCreateSymLink(c *gc.C) {
	target, err := symlink.GetLongPathAsString(c.MkDir())
	c.Assert(err, gc.IsNil)

	link := filepath.Join(target, "link")

	_, err = os.Stat(target)
	c.Assert(err, gc.IsNil)

	err = symlink.New(target, link)
	c.Assert(err, gc.IsNil)

	link, err = symlink.Read(link)
	c.Assert(err, gc.IsNil)
	c.Assert(link, gc.Equals, filepath.FromSlash(target))
}

func (s *BaseRepoSuite) SetUpTest(c *gc.C) {
	// Set up a local repository.
	s.RepoPath = os.Getenv("JUJU_REPOSITORY")
	repoPath := c.MkDir()
	os.Setenv("JUJU_REPOSITORY", repoPath)
	s.SeriesPath = filepath.Join(repoPath, config.LatestLtsSeries())
	c.Assert(os.Mkdir(s.SeriesPath, 0777), jc.ErrorIsNil)
	// Create a symlink "quantal" -> "precise", because most charms
	// and machines are written with hard-coded "quantal" series,
	// hence they interact badly with a local repository that assumes
	// only "precise" charms are available.
	err := symlink.New(s.SeriesPath, filepath.Join(repoPath, "quantal"))
	c.Assert(err, jc.ErrorIsNil)
	s.BundlesPath = filepath.Join(repoPath, "bundle")
	c.Assert(os.Mkdir(s.BundlesPath, 0777), jc.ErrorIsNil)
}

func (*SymlinkSuite) TestIsSymlinkFolder(c *gc.C) {
	target, err := symlink.GetLongPathAsString(c.MkDir())
	c.Assert(err, gc.IsNil)

	link := filepath.Join(target, "link")

	_, err = os.Stat(target)
	c.Assert(err, gc.IsNil)

	err = symlink.New(target, link)
	c.Assert(err, gc.IsNil)

	isSymlink, err := symlink.IsSymlink(link)
	c.Assert(err, gc.IsNil)
	c.Assert(isSymlink, jc.IsTrue)
}

func (s *GitDeployerSuite) TestUpgrade(c *gc.C) {
	// Install.
	info1 := s.bundles.AddCustomBundle(c, corecharm.MustParseURL("cs:s/c-1"), func(path string) {
		err := ioutil.WriteFile(filepath.Join(path, "some-file"), []byte("hello"), 0644)
		c.Assert(err, jc.ErrorIsNil)
		err = symlink.New("./some-file", filepath.Join(path, "a-symlink"))
		c.Assert(err, jc.ErrorIsNil)
	})
	err := s.deployer.Stage(info1, nil)
	c.Assert(err, jc.ErrorIsNil)
	err = s.deployer.Deploy()
	c.Assert(err, jc.ErrorIsNil)

	// Upgrade.
	info2 := s.bundles.AddCustomBundle(c, corecharm.MustParseURL("cs:s/c-2"), func(path string) {
		err := ioutil.WriteFile(filepath.Join(path, "some-file"), []byte("goodbye"), 0644)
		c.Assert(err, jc.ErrorIsNil)
		err = ioutil.WriteFile(filepath.Join(path, "a-symlink"), []byte("not any more!"), 0644)
		c.Assert(err, jc.ErrorIsNil)
	})
	err = s.deployer.Stage(info2, nil)
	c.Assert(err, jc.ErrorIsNil)
	checkCleanup(c, s.deployer)
	err = s.deployer.Deploy()
	c.Assert(err, jc.ErrorIsNil)
	checkCleanup(c, s.deployer)

	// Check content.
	data, err := ioutil.ReadFile(filepath.Join(s.targetPath, "some-file"))
	c.Assert(err, jc.ErrorIsNil)
	c.Assert(string(data), gc.Equals, "goodbye")
	data, err = ioutil.ReadFile(filepath.Join(s.targetPath, "a-symlink"))
	c.Assert(err, jc.ErrorIsNil)
	c.Assert(string(data), gc.Equals, "not any more!")

	target := charm.NewGitDir(s.targetPath)
	url, err := target.ReadCharmURL()
	c.Assert(err, jc.ErrorIsNil)
	c.Assert(url, gc.DeepEquals, corecharm.MustParseURL("cs:s/c-2"))
	lines, err := target.Log()
	c.Assert(err, jc.ErrorIsNil)
	c.Assert(lines, gc.HasLen, 5)
	c.Assert(lines[0], gc.Matches, `[0-9a-f]{7} Upgraded charm to "cs:s/c-2".`)
}

func (s *prereqsSuite) SetUpTest(c *gc.C) {
	s.BaseSuite.SetUpTest(c)
	s.tmpdir = c.MkDir()
	s.testMongodPath = filepath.Join(s.tmpdir, "mongod")

	s.PatchEnvironment("PATH", s.tmpdir)

	s.PatchValue(&mongo.JujuMongodPath, "/somewhere/that/wont/exist")

	os.Setenv("JUJUTEST_LSB_RELEASE_ID", "Ubuntu")
	err := ioutil.WriteFile(filepath.Join(s.tmpdir, "lsb_release"), []byte(lsbrelease), 0777)
	c.Assert(err, gc.IsNil)

	// symlink $temp/dpkg-query to /bin/true, to
	// simulate package installation query responses.
	err = symlink.New("/bin/true", filepath.Join(s.tmpdir, "dpkg-query"))
	c.Assert(err, gc.IsNil)
	s.PatchValue(&isPackageInstalled, apt.IsPackageInstalled)
}

func autostartContainer(name string) error {
	// Now symlink the config file into the restart directory, if it exists.
	// This is for backwards compatiblity. From Trusty onwards, the auto start
	// option should be set in the LXC config file, this is done in the networkConfigTemplate
	// function below.
	if useRestartDir() {
		if err := symlink.New(
			containerConfigFilename(name),
			restartSymlink(name),
		); err != nil {
			return err
		}
		logger.Tracef("auto-restart link created")
	} else {
		logger.Tracef("Setting auto start to true in lxc config.")
		return appendToContainerConfig(name, "lxc.start.auto = 1\n")
	}
	return nil
}

func (*SymlinkSuite) TestIsSymlinkFile(c *gc.C) {
	dir, err := symlink.GetLongPathAsString(c.MkDir())
	c.Assert(err, gc.IsNil)

	target := filepath.Join(dir, "file")
	err = ioutil.WriteFile(target, []byte("TOP SECRET"), 0644)
	c.Assert(err, gc.IsNil)

	link := filepath.Join(dir, "link")

	_, err = os.Stat(target)
	c.Assert(err, gc.IsNil)

	err = symlink.New(target, link)
	c.Assert(err, gc.IsNil)

	isSymlink, err := symlink.IsSymlink(link)
	c.Assert(err, gc.IsNil)
	c.Assert(isSymlink, jc.IsTrue)
}

func (s *RepoSuite) SetUpTest(c *gc.C) {
	s.JujuConnSuite.SetUpTest(c)
	// Change the environ's config to ensure we're using the one in state,
	// not the one in the local environments.yaml
	updateAttrs := map[string]interface{}{"default-series": config.LatestLtsSeries()}
	err := s.State.UpdateEnvironConfig(updateAttrs, nil, nil)
	c.Assert(err, jc.ErrorIsNil)
	s.RepoPath = os.Getenv("JUJU_REPOSITORY")
	repoPath := c.MkDir()
	os.Setenv("JUJU_REPOSITORY", repoPath)
	s.SeriesPath = filepath.Join(repoPath, config.LatestLtsSeries())
	err = os.Mkdir(s.SeriesPath, 0777)
	c.Assert(err, jc.ErrorIsNil)
	// Create a symlink "quantal" -> "precise", because most charms
	// and machines are written with hard-coded "quantal" series,
	// hence they interact badly with a local repository that assumes
	// only "precise" charms are available.
	err = symlink.New(s.SeriesPath, filepath.Join(repoPath, "quantal"))
	c.Assert(err, jc.ErrorIsNil)
}

func (*SymlinkSuite) TestReadData(c *gc.C) {
	dir := c.MkDir()
	sub := filepath.Join(dir, "sub")

	err := os.Mkdir(sub, 0700)
	c.Assert(err, gc.IsNil)

	oldname := filepath.Join(sub, "foo")
	data := []byte("data")

	err = ioutil.WriteFile(oldname, data, 0644)
	c.Assert(err, gc.IsNil)

	newname := filepath.Join(dir, "bar")
	err = symlink.New(oldname, newname)
	c.Assert(err, gc.IsNil)

	b, err := ioutil.ReadFile(newname)
	c.Assert(err, gc.IsNil)

	c.Assert(string(b), gc.Equals, string(data))
}

// EnsureSymlinks creates a symbolic link to jujuc within dir for each
// hook command. If the commands already exist, this operation does nothing.
// If dir is a symbolic link, it will be dereferenced first.
func EnsureSymlinks(dir string) (err error) {
	logger.Infof("ensure jujuc symlinks in %s", dir)
	defer func() {
		if err != nil {
			err = errors.Annotatef(err, "cannot initialize hook commands in %q", dir)
		}
	}()
	isSymlink, err := symlink.IsSymlink(dir)
	if err != nil {
		return err
	}
	if isSymlink {
		link, err := symlink.Read(dir)
		if err != nil {
			return err
		}
		if !filepath.IsAbs(link) {
			logger.Infof("%s is relative", link)
			link = filepath.Join(filepath.Dir(dir), link)
		}
		dir = link
		logger.Infof("was a symlink, now looking at %s", dir)
	}

	jujudPath := filepath.Join(dir, names.Jujud)
	logger.Debugf("jujud path %s", jujudPath)
	for _, name := range CommandNames() {
		// The link operation fails when the target already exists,
		// so this is a no-op when the command names already
		// exist.
		err := symlink.New(jujudPath, filepath.Join(dir, name))
		if err != nil && !os.IsExist(err) {
			return err
		}
	}
	return nil
}