// VendoredCleanup cleans up vendored codebases after an update.
//
// This should _only_ be run for installations that do not want VCS repos inside
// of the vendor/ directory.
func VendoredCleanup(conf *cfg.Config) error {
	vend, err := gpath.Vendor()
	if err != nil {
		return err
	}

	for _, dep := range conf.Imports {
		if dep.UpdateAsVendored == true {
			msg.Info("Cleaning up vendored package %s\n", dep.Name)

			// Remove the VCS directory
			cwd := filepath.Join(vend, dep.Name)
			repo, err := dep.GetRepo(cwd)
			if err != nil {
				msg.Err("Error cleaning up %s:%s", dep.Name, err)
				continue
			}
			t := repo.Vcs()
			err = os.RemoveAll(cwd + string(os.PathSeparator) + "." + string(t))
			if err != nil {
				msg.Err("Error cleaning up VCS dir for %s:%s", dep.Name, err)
			}
		}

	}

	return nil
}

// MirrorsSet sets a mirror to use
func MirrorsSet(o, r, v string) error {
	if o == "" || r == "" {
		msg.Err("Both the original and mirror values are required")
		return nil
	}

	home := gpath.Home()

	op := filepath.Join(home, "mirrors.yaml")

	var ov *mirrors.Mirrors
	if _, err := os.Stat(op); os.IsNotExist(err) {
		msg.Info("No mirrors.yaml file exists. Creating new one")
		ov = &mirrors.Mirrors{
			Repos: make(mirrors.MirrorRepos, 0),
		}
	} else {
		ov, err = mirrors.ReadMirrorsFile(op)
		if err != nil {
			msg.Die("Error reading existing mirrors.yaml file: %s", err)
		}
	}

	found := false
	for i, re := range ov.Repos {
		if re.Original == o {
			found = true
			msg.Info("%s found in mirrors. Replacing with new settings", o)
			ov.Repos[i].Repo = r
			ov.Repos[i].Vcs = v
		}
	}

	if !found {
		nr := &mirrors.MirrorRepo{
			Original: o,
			Repo:     r,
			Vcs:      v,
		}
		ov.Repos = append(ov.Repos, nr)
	}

	msg.Info("%s being set to %s", o, r)

	err := ov.WriteFile(op)
	if err != nil {
		msg.Err("Error writing mirrors.yaml file: %s", err)
	} else {
		msg.Info("mirrors.yaml written with changes")
	}

	return nil
}

// queueUnseenImports scans a package's imports and adds any new ones to the
// processing queue.
func (r *Resolver) queueUnseen(pkg string, queue *list.List) error {
	// A pkg is marked "seen" as soon as we have inspected it the first time.
	// Seen means that we have added all of its imports to the list.

	// Already queued indicates that we've either already put it into the queue
	// or intentionally not put it in the queue for fatal reasons (e.g. no
	// buildable source).

	deps, err := r.imports(pkg)
	if err != nil && !strings.HasPrefix(err.Error(), "no buildable Go source") {
		msg.Err("Could not find %s: %s", pkg, err)
		return err
		// NOTE: If we uncomment this, we get lots of "no buildable Go source" errors,
		// which don't ever seem to be helpful. They don't actually indicate an error
		// condition, and it's perfectly okay to run into that condition.
		//} else if err != nil {
		//	msg.Warn(err.Error())
	}

	for _, d := range deps {
		if _, ok := r.alreadyQ[d]; !ok {
			r.alreadyQ[d] = true
			queue.PushBack(d)
		}
	}
	return nil
}

// EnsureGoVendor ensures that the Go version is correct.
func EnsureGoVendor() {
	// 6l was removed in 1.5, when vendoring was introduced.
	cmd := exec.Command("go", "tool", "6l")
	if _, err := cmd.CombinedOutput(); err == nil {
		msg.Warn("You must install the Go 1.5 or greater toolchain to work with Glide.\n")
		os.Exit(1)
	}

	// This works with 1.5 and >=1.6.
	cmd = exec.Command("go", "env", "GO15VENDOREXPERIMENT")
	if out, err := cmd.CombinedOutput(); err != nil {
		msg.Err("Error looking for $GOVENDOREXPERIMENT: %s.\n", err)
		os.Exit(1)
	} else if strings.TrimSpace(string(out)) != "1" {
		msg.Warn("To use Glide, you must set GO15VENDOREXPERIMENT=1\n")
		os.Exit(1)
	}

	// Verify the setup isn't for the old version of glide. That is, this is
	// no longer assuming the _vendor directory as the GOPATH. Inform of
	// the change.
	if _, err := os.Stat("_vendor/"); err == nil {
		msg.Warn(`Your setup appears to be for the previous version of Glide.
Previously, vendor packages were stored in _vendor/src/ and
_vendor was set as your GOPATH. As of Go 1.5 the go tools
recognize the vendor directory as a location for these
files. Glide has embraced this. Please remove the _vendor
directory or move the _vendor/src/ directory to vendor/.` + "\n")
		os.Exit(1)
	}
}

// OnGopath will either copy a package, already found in the GOPATH, to the
// vendor/ directory or download it from the internet. This is dependent if
// useGopath on the installer is set to true to copy from the GOPATH.
func (m *MissingPackageHandler) OnGopath(pkg string) (bool, error) {
	// If useGopath is false, we fall back to the strategy of fetching from
	// remote.
	if !m.useGopath {
		return m.NotFound(pkg)
	}

	root := util.GetRootFromPackage(pkg)

	// Skip any references to the root package.
	if root == m.Config.Name {
		return false, nil
	}

	msg.Info("Copying package %s from the GOPATH.", pkg)
	dest := filepath.Join(m.destination, pkg)
	// Find package on Gopath
	for _, gp := range gpath.Gopaths() {
		src := filepath.Join(gp, pkg)
		// FIXME: Should probably check if src is a dir or symlink.
		if _, err := os.Stat(src); err == nil {
			if err := os.MkdirAll(dest, os.ModeDir|0755); err != nil {
				return false, err
			}
			if err := gpath.CopyDir(src, dest); err != nil {
				return false, err
			}
			return true, nil
		}
	}

	msg.Err("Could not locate %s on the GOPATH, though it was found before.", pkg)
	return false, nil
}

// Get fetches one or more dependencies and installs.
//
// This includes resolving dependency resolution and re-generating the lock file.
func Get(names []string, installer *repo.Installer, insecure, skipRecursive bool) {
	base := gpath.Basepath()
	EnsureGopath()
	EnsureVendorDir()
	conf := EnsureConfig()
	glidefile, err := gpath.Glide()
	if err != nil {
		msg.Die("Could not find Glide file: %s", err)
	}

	// Add the packages to the config.
	if err := addPkgsToConfig(conf, names, insecure); err != nil {
		msg.Die("Failed to get new packages: %s", err)
	}

	// Fetch the new packages. Can't resolve versions via installer.Update if
	// get is called while the vendor/ directory is empty so we checkout
	// everything.
	installer.Checkout(conf, false)

	// Prior to resolving dependencies we need to start working with a clone
	// of the conf because we'll be making real changes to it.
	confcopy := conf.Clone()

	if !skipRecursive {
		// Get all repos and update them.
		// TODO: Can we streamline this in any way? The reason that we update all
		// of the dependencies is that we need to re-negotiate versions. For example,
		// if an existing dependency has the constraint >1.0 and this new package
		// adds the constraint <2.0, then this may re-resolve the existing dependency
		// to be between 1.0 and 2.0. But changing that dependency may then result
		// in that dependency's dependencies changing... so we sorta do the whole
		// thing to be safe.
		err = installer.Update(confcopy)
		if err != nil {
			msg.Die("Could not update packages: %s", err)
		}
	}

	// Set Reference
	if err := repo.SetReference(confcopy); err != nil {
		msg.Err("Failed to set references: %s", err)
	}

	// VendoredCleanup
	if installer.UpdateVendored {
		repo.VendoredCleanup(confcopy)
	}

	// Write YAML
	if err := conf.WriteFile(glidefile); err != nil {
		msg.Die("Failed to write glide YAML file: %s", err)
	}
	if !skipRecursive {
		// Write lock
		writeLock(conf, confcopy, base)
	} else {
		msg.Warn("Skipping lockfile generation because full dependency tree is not being calculated")
	}
}

// Process imports dependencies for a package
func (d *VersionHandler) Process(pkg string) (e error) {
	root := util.GetRootFromPackage(pkg)

	// Skip any references to the root package.
	if root == d.Config.Name {
		return nil
	}

	// We have not tried to import, yet.
	// Should we look in places other than the root of the project?
	if d.Imported[root] == false {
		d.Imported[root] = true
		p := filepath.Join(d.Destination, root)
		f, deps, err := importer.Import(p)
		if f && err == nil {
			for _, dep := range deps {

				// The fist one wins. Would something smater than this be better?
				exists, _ := d.Use.Get(dep.Name)
				if exists == nil && (dep.Reference != "" || dep.Repository != "") {
					d.Use.Add(dep.Name, dep, root)
				}
			}
		} else if err != nil {
			msg.Err("Unable to import from %s. Err: %s", root, err)
			e = err
		}
	}

	return
}

// MirrorsRemove removes a mirrors setting
func MirrorsRemove(k string) error {
	if k == "" {
		msg.Err("The mirror to remove is required")
		return nil
	}

	home := gpath.Home()

	op := filepath.Join(home, "mirrors.yaml")

	if _, err := os.Stat(op); os.IsNotExist(err) {
		msg.Err("mirrors.yaml file not found")
		return nil
	}

	ov, err := mirrors.ReadMirrorsFile(op)
	if err != nil {
		msg.Die("Unable to read mirrors.yaml file: %s", err)
	}

	var nre mirrors.MirrorRepos
	var found bool
	for _, re := range ov.Repos {
		if re.Original != k {
			nre = append(nre, re)
		} else {
			found = true
		}
	}

	if !found {
		msg.Warn("%s was not found in mirrors", k)
	} else {
		msg.Info("%s was removed from mirrors", k)
		ov.Repos = nre

		err = ov.WriteFile(op)
		if err != nil {
			msg.Err("Error writing mirrors.yaml file: %s", err)
		} else {
			msg.Info("mirrors.yaml written with changes")
		}
	}

	return nil
}

// EnsureConfig loads and returns a config file.
//
// Any error will cause an immediate exit, with an error printed to Stderr.
func EnsureConfig() *cfg.Config {
	yamlpath, err := gpath.Glide()
	if err != nil {
		msg.ExitCode(2)
		msg.Die("Failed to find %s file in directory tree: %s", gpath.GlideFile, err)
	}

	yml, err := ioutil.ReadFile(yamlpath)
	if err != nil {
		msg.ExitCode(2)
		msg.Die("Failed to load %s: %s", yamlpath, err)
	}
	conf, err := cfg.ConfigFromYaml(yml)
	if err != nil {
		msg.ExitCode(3)
		msg.Die("Failed to parse %s: %s", yamlpath, err)
	}

	b := filepath.Dir(yamlpath)
	buildContext, err := util.GetBuildContext()
	if err != nil {
		msg.Die("Failed to build an import context while ensuring config: %s", err)
	}
	cwd, err := os.Getwd()
	if err != nil {
		msg.Err("Unable to get the current working directory")
	} else {
		// Determining a package name requires a relative path
		b, err = filepath.Rel(b, cwd)
		if err == nil {
			name := buildContext.PackageName(b)
			if name != conf.Name {
				msg.Warn("The name listed in the config file (%s) does not match the current location (%s)", conf.Name, name)
			}
		} else {
			msg.Warn("Problem finding the config file path (%s) relative to the current directory (%s): %s", b, cwd, err)
		}
	}

	err = mirrors.Load()
	if err != nil {
		msg.Err("Unable to load mirrors: %s", err)
	}

	return conf
}

// Plugin attempts to find and execute a plugin based on a command.
//
// Exit code 99 means the plugin was never executed. Code 1 means the program
// exited badly.
func Plugin(command string, args []string) {

	cwd, err := os.Getwd()
	if err != nil {
		msg.ExitCode(99)
		msg.Die("Could not get working directory: %s", err)
	}

	cmd := "glide-" + command
	var fullcmd string
	if fullcmd, err = exec.LookPath(cmd); err != nil {
		fullcmd = cwd + "/" + cmd
		if _, err := os.Stat(fullcmd); err != nil {
			msg.ExitCode(99)
			msg.Die("Command %s does not exist.", cmd)
		}
	}

	// Turning os.Args first argument from `glide` to `glide-command`
	args[0] = cmd
	// Removing the first argument (command)
	removed := false
	for i, v := range args {
		if removed == false && v == command {
			args = append(args[:i], args[i+1:]...)
			removed = true
		}
	}
	pa := os.ProcAttr{
		Files: []*os.File{os.Stdin, os.Stdout, os.Stderr},
		Dir:   cwd,
	}

	msg.Debug("Delegating to plugin %s (%v)\n", fullcmd, args)

	proc, err := os.StartProcess(fullcmd, args, &pa)
	if err != nil {
		msg.Err("Failed to execute %s: %s", cmd, err)
		os.Exit(98)
	}

	if _, err := proc.Wait(); err != nil {
		msg.Err(err.Error())
		os.Exit(1)
	}
}

// SetReference is a command to set the VCS reference (commit id, tag, etc) for
// a project.
func SetReference(conf *cfg.Config, resolveTest bool) error {

	cwd, err := gpath.Vendor()
	if err != nil {
		return err
	}

	if len(conf.Imports) == 0 && len(conf.DevImports) == 0 {
		msg.Info("No references set.\n")
		return nil
	}

	done := make(chan struct{}, concurrentWorkers)
	in := make(chan *cfg.Dependency, concurrentWorkers)
	var wg sync.WaitGroup

	for i := 0; i < concurrentWorkers; i++ {
		go func(ch <-chan *cfg.Dependency) {
			for {
				select {
				case dep := <-ch:
					if err := VcsVersion(dep, cwd); err != nil {
						msg.Err("Failed to set version on %s to %s: %s\n", dep.Name, dep.Reference, err)
					}
					wg.Done()
				case <-done:
					return
				}
			}
		}(in)
	}

	for _, dep := range conf.Imports {
		if !conf.HasIgnore(dep.Name) {
			wg.Add(1)
			in <- dep
		}
	}

	if resolveTest {
		for _, dep := range conf.DevImports {
			if !conf.HasIgnore(dep.Name) {
				wg.Add(1)
				in <- dep
			}
		}
	}

	wg.Wait()
	// Close goroutines setting the version
	for i := 0; i < concurrentWorkers; i++ {
		done <- struct{}{}
	}
	// close(done)
	// close(in)

	return nil
}

// EnsureGoVendor ensures that the Go version is correct.
func EnsureGoVendor() {
	// 6l was removed in 1.5, when vendoring was introduced.
	cmd := exec.Command(goExecutable(), "tool", "6l")
	if _, err := cmd.CombinedOutput(); err == nil {
		msg.Warn("You must install the Go 1.5 or greater toolchain to work with Glide.\n")
		os.Exit(1)
	}

	// Check if this is go15, which requires GO15VENDOREXPERIMENT
	// Any release after go15 does not require that env var.
	cmd = exec.Command(goExecutable(), "version")
	if out, err := cmd.CombinedOutput(); err != nil {
		msg.Err("Error getting version: %s.\n", err)
		os.Exit(1)
	} else if strings.HasPrefix(string(out), "go version 1.5") {
		// This works with 1.5 and 1.6.
		cmd = exec.Command(goExecutable(), "env", "GO15VENDOREXPERIMENT")
		if out, err := cmd.CombinedOutput(); err != nil {
			msg.Err("Error looking for $GOVENDOREXPERIMENT: %s.\n", err)
			os.Exit(1)
		} else if strings.TrimSpace(string(out)) != "1" {
			msg.Err("To use Glide, you must set GO15VENDOREXPERIMENT=1")
			os.Exit(1)
		}
	}

	// In the case where vendoring is explicitly disabled, balk.
	if os.Getenv("GO15VENDOREXPERIMENT") == "0" {
		msg.Err("To use Glide, you must set GO15VENDOREXPERIMENT=1")
		os.Exit(1)
	}

	// Verify the setup isn't for the old version of glide. That is, this is
	// no longer assuming the _vendor directory as the GOPATH. Inform of
	// the change.
	if _, err := os.Stat("_vendor/"); err == nil {
		msg.Warn(`Your setup appears to be for the previous version of Glide.
Previously, vendor packages were stored in _vendor/src/ and
_vendor was set as your GOPATH. As of Go 1.5 the go tools
recognize the vendor directory as a location for these
files. Glide has embraced this. Please remove the _vendor
directory or move the _vendor/src/ directory to vendor/.` + "\n")
		os.Exit(1)
	}
}

func main() {
	app := cli.NewApp()
	app.Name = "glide"
	app.Usage = usage
	app.Version = version
	app.Flags = []cli.Flag{
		cli.StringFlag{
			Name:  "yaml, y",
			Value: "glide.yaml",
			Usage: "Set a YAML configuration file.",
		},
		cli.BoolFlag{
			Name:  "quiet, q",
			Usage: "Quiet (no info or debug messages)",
		},
		cli.BoolFlag{
			Name:  "debug",
			Usage: "Print debug verbose informational messages",
		},
		cli.StringFlag{
			Name:   "home",
			Value:  gpath.Home(),
			Usage:  "The location of Glide files",
			EnvVar: "GLIDE_HOME",
		},
		cli.StringFlag{
			Name:   "tmp",
			Value:  "",
			Usage:  "The temp directory to use. Defaults to systems temp",
			EnvVar: "GLIDE_TMP",
		},
		cli.BoolFlag{
			Name:  "no-color",
			Usage: "Turn off colored output for log messages",
		},
	}
	app.CommandNotFound = func(c *cli.Context, command string) {
		// TODO: Set some useful env vars.
		action.Plugin(command, os.Args)
	}
	app.Before = startup
	app.After = shutdown
	app.Commands = commands()

	// Detect errors from the Before and After calls and exit on them.
	if err := app.Run(os.Args); err != nil {
		msg.Err(err.Error())
		os.Exit(1)
	}

	// If there was a Error message exit non-zero.
	if msg.HasErrored() {
		m := msg.Color(msg.Red, "An Error has occurred")
		msg.Msg(m)
		os.Exit(2)
	}
}

// Install installs a vendor directory based on an existing Glide configuration.
func Install(installer *repo.Installer, stripVendor bool) {
	cache.SystemLock()

	base := "."
	// Ensure GOPATH
	EnsureGopath()
	EnsureVendorDir()
	conf := EnsureConfig()

	// Lockfile exists
	if !gpath.HasLock(base) {
		msg.Info("Lock file (glide.lock) does not exist. Performing update.")
		Update(installer, false, stripVendor)
		return
	}
	// Load lockfile
	lock, err := cfg.ReadLockFile(filepath.Join(base, gpath.LockFile))
	if err != nil {
		msg.Die("Could not load lockfile.")
	}
	// Verify lockfile hasn't changed
	hash, err := conf.Hash()
	if err != nil {
		msg.Die("Could not load lockfile.")
	} else if hash != lock.Hash {
		fmt.Println(hash, lock.Hash)
		foo, _ := conf.Marshal()
		fmt.Println(string(foo))
		msg.Warn("Lock file may be out of date. Hash check of YAML failed. You may need to run 'update'")
	}

	// Install
	newConf, err := installer.Install(lock, conf)
	if err != nil {
		msg.Die("Failed to install: %s", err)
	}

	msg.Info("Setting references.")

	// Set reference
	if err := repo.SetReference(newConf, installer.ResolveTest); err != nil {
		msg.Die("Failed to set references: %s (Skip to cleanup)", err)
	}

	err = installer.Export(newConf)
	if err != nil {
		msg.Die("Unable to export dependencies to vendor directory: %s", err)
	}

	if stripVendor {
		msg.Info("Removing nested vendor and Godeps/_workspace directories...")
		err := gpath.StripVendor()
		if err != nil {
			msg.Err("Unable to strip vendor directories: %s", err)
		}
	}
}

func walkDeps(b *util.BuildCtxt, base, myName string) []string {
	externalDeps := []string{}
	filepath.Walk(base, func(path string, fi os.FileInfo, err error) error {
		if err != nil {
			return err
		}

		if !dependency.IsSrcDir(fi) {
			if fi.IsDir() {
				return filepath.SkipDir
			}
			return nil
		}

		var imps []string
		pkg, err := b.ImportDir(path, 0)
		if err != nil && strings.HasPrefix(err.Error(), "found packages ") {
			// If we got here it's because a package and multiple packages
			// declared. This is often because of an example with a package
			// or main but +build ignore as a build tag. In that case we
			// try to brute force the packages with a slower scan.
			imps, _, err = dependency.IterativeScan(path)
			if err != nil {
				msg.Err("Error walking dependencies for %s: %s", path, err)
				return err
			}
		} else if err != nil {
			if !strings.HasPrefix(err.Error(), "no buildable Go source") {
				msg.Warn("Error: %s (%s)", err, path)
				// Not sure if we should return here.
				//return err
			}
		} else {
			imps = pkg.Imports
		}

		if pkg.Goroot {
			return nil
		}

		for _, imp := range imps {
			//if strings.HasPrefix(imp, myName) {
			////Info("Skipping %s because it is a subpackage of %s", imp, myName)
			//continue
			//}
			if imp == myName {
				continue
			}
			externalDeps = append(externalDeps, imp)
		}

		return nil
	})
	return externalDeps
}

// ConcurrentUpdate takes a list of dependencies and updates in parallel.
func ConcurrentUpdate(deps []*cfg.Dependency, i *Installer, c *cfg.Config) error {
	done := make(chan struct{}, concurrentWorkers)
	in := make(chan *cfg.Dependency, concurrentWorkers)
	var wg sync.WaitGroup
	var lock sync.Mutex
	var returnErr error

	for ii := 0; ii < concurrentWorkers; ii++ {
		go func(ch <-chan *cfg.Dependency) {
			for {
				select {
				case dep := <-ch:
					loc := dep.Remote()
					key, err := cache.Key(loc)
					if err != nil {
						msg.Die(err.Error())
					}
					cache.Lock(key)
					if err := VcsUpdate(dep, i.Force, i.Updated); err != nil {
						msg.Err("Update failed for %s: %s\n", dep.Name, err)
						// Capture the error while making sure the concurrent
						// operations don't step on each other.
						lock.Lock()
						if returnErr == nil {
							returnErr = err
						} else {
							returnErr = cli.NewMultiError(returnErr, err)
						}
						lock.Unlock()
					}
					cache.Unlock(key)
					wg.Done()
				case <-done:
					return
				}
			}
		}(in)
	}

	for _, dep := range deps {
		if !c.HasIgnore(dep.Name) {
			wg.Add(1)
			in <- dep
		}
	}

	wg.Wait()

	// Close goroutines setting the version
	for ii := 0; ii < concurrentWorkers; ii++ {
		done <- struct{}{}
	}

	return returnErr
}

// NoVendor generates a list of source code directories, excepting `vendor/`.
//
// If "onlyGo" is true, only folders that have Go code in them will be returned.
//
// If suffix is true, this will append `/...` to every directory.
func NoVendor(path string, onlyGo, suffix bool) {
	// This is responsible for printing the results of noVend.
	paths, err := noVend(path, onlyGo, suffix)
	if err != nil {
		msg.Err("Failed to walk file tree: %s", err)
		msg.Warn("FIXME: NoVendor should exit with non-zero exit code.")
		return
	}

	for _, p := range paths {
		msg.Puts(p)
	}
}

// ConcurrentUpdate takes a list of dependencies and updates in parallel.
func ConcurrentUpdate(deps []*cfg.Dependency, cwd string, i *Installer) error {
	done := make(chan struct{}, concurrentWorkers)
	in := make(chan *cfg.Dependency, concurrentWorkers)
	var wg sync.WaitGroup
	var lock sync.Mutex
	var returnErr error

	msg.Info("Downloading dependencies. Please wait...")

	for ii := 0; ii < concurrentWorkers; ii++ {
		go func(ch <-chan *cfg.Dependency) {
			for {
				select {
				case dep := <-ch:
					dest := filepath.Join(i.VendorPath(), dep.Name)
					if err := VcsUpdate(dep, dest, i.Home, i.UseCache, i.UseCacheGopath, i.UseGopath, i.Force, i.UpdateVendored); err != nil {
						msg.Err("Update failed for %s: %s\n", dep.Name, err)
						// Capture the error while making sure the concurrent
						// operations don't step on each other.
						lock.Lock()
						if returnErr == nil {
							returnErr = err
						} else {
							returnErr = cli.NewMultiError(returnErr, err)
						}
						lock.Unlock()
					}
					wg.Done()
				case <-done:
					return
				}
			}
		}(in)
	}

	for _, dep := range deps {
		wg.Add(1)
		in <- dep
	}

	wg.Wait()

	// Close goroutines setting the version
	for ii := 0; ii < concurrentWorkers; ii++ {
		done <- struct{}{}
	}

	return returnErr
}

// Install installs a vendor directory based on an existing Glide configuration.
func Install(installer *repo.Installer) {
	base := "."
	// Ensure GOPATH
	EnsureGopath()
	EnsureVendorDir()
	conf := EnsureConfig()

	// Lockfile exists
	if !gpath.HasLock(base) {
		msg.Info("Lock file (glide.lock) does not exist. Performing update.")
		Update(installer, false)
		return
	}
	// Load lockfile
	lock, err := LoadLockfile(base, conf)
	if err != nil {
		msg.Die("Could not load lockfile.")
	}

	// Delete unused packages
	if installer.DeleteUnused {
		// It's unclear whether this should operate off of the lock, or off
		// of the glide.yaml file. I'd think that doing this based on the
		// lock would be much more reliable.
		dependency.DeleteUnused(conf)
	}

	// Install
	newConf, err := installer.Install(lock, conf)
	if err != nil {
		msg.Die("Failed to install: %s", err)
	}

	msg.Info("Setting references.")

	// Set reference
	if err := repo.SetReference(newConf); err != nil {
		msg.Err("Failed to set references: %s (Skip to cleanup)", err)
	}

	// VendoredCleanup. This should ONLY be run if UpdateVendored was specified.
	if installer.UpdateVendored {
		repo.VendoredCleanup(newConf)
	}
}

// EnsureGopath fails if GOPATH is not set, or if $GOPATH/src is missing.
//
// Otherwise it returns the value of GOPATH.
func EnsureGopath() string {
	gps := gpath.Gopaths()
	if len(gps) == 0 {
		msg.Die("$GOPATH is not set.")
	}

	for _, gp := range gps {
		_, err := os.Stat(path.Join(gp, "src"))
		if err != nil {
			msg.Warn("%s", err)
			continue
		}
		return gp
	}

	msg.Err("Could not find any of %s/src.\n", strings.Join(gps, "/src, "))
	msg.Info("As of Glide 0.5/Go 1.5, this is required.\n")
	msg.Die("Wihtout src, cannot continue.")
	return ""
}