// Resolve dependencies in a dependency list
// Resolves dependencies in order they occured originally
func (d *DependencyList) Resolve() error {
	if d == nil {
		log.Debug("No dependencies to resolve")
		return nil
	}

	log.Debug("Resolving dependencies")

	errs := make([]string, 0)

	for _, dep := range d.Dependencies {
		log.Debug("Resolving module dependency: %s", dep)
		if err := dep.Resolve(d.Parent); err != nil {
			log.Error("Error resolving module dependencies [%s]: %s", dep, err)
			errs = append(errs, dep.String())
			break
		}
	}

	if len(errs) > 0 {
		log.Error("Failed to find dependencies:")
		for _, err := range errs {
			log.Error("=> %s", err)
		}
		return errors.New("Failed to find dependencies")
	}

	return nil
}

func ParseCPANLines(lines []string) (*CPANFile, error) {
	cpanfile := &CPANFile{}

	for _, l := range lines {
		if len(l) == 0 {
			continue
		}

		log.Trace("Parsing line: %s", l)
		dep, err := ParseCPANLine(l)

		if err != nil {
			log.Error("=> Error parsing line: %s", err)
			continue
		}

		if dep != nil {
			log.Info("=> Found dependency: %s", dep)
			cpanfile.AddDependency(dep)
			continue
		}

		log.Trace("=> No error and no dependency found")
	}

	log.Info("Found %d dependencies in cpanfile", len(cpanfile.Dependencies))

	return cpanfile, nil
}

func SaveIndex(index string, indexes map[string]*Source) {
	// TODO append, but needs to know which stuff is new
	//out, err := os.OpenFile(".gopancache/index", os.O_RDWR|os.O_APPEND, 0660)
	out, err := os.Create(index)
	if err != nil {
		log.Error("Error creating index: %s", err.Error())
	}
	for _, source := range indexes {
		out.Write([]byte(source.Name + " [" + source.URL + "]\n"))
		log.Trace(source.Name)
		for _, author := range source.Authors {
			out.Write([]byte(" " + author.Name + " [" + author.URL + "]\n"))
			log.Trace("    %s", author.Name)
			for _, pkg := range author.Packages {
				out.Write([]byte("  " + pkg.Name + " => " + pkg.URL + "\n"))
				log.Trace("        %s => %s", pkg.Name, pkg.URL)
				for p, pk := range pkg.Provides {
					out.Write([]byte("   " + p + " (" + pk.Version + "): " + pk.File + "\n"))
					log.Trace("          %s (%s): %s", p, pk.Version, pk.File)
				}
			}
		}
	}
	out.Close()
}

func WatchConfig(configWrapper iConfigWrapper, configPath string) {
	watcherForConfigFile, err := fsnotify.NewWatcher()
	CheckError(err)

	go func() {
		for {
			select {
			case e := <-watcherForConfigFile.Event:
				if lastConfigModifiedTime.Add(1 * time.Second).After(time.Now()) {
					continue
				}
				lastConfigModifiedTime = time.Now()

				// log.Warn("Config '%s' modified, but NOT RELOADING YET.", e.Name)
				log.Warn("Config '%s' modified, now reloading (most of the) config settings.", e.Name)
				configWrapper.SetConfig(loadFile(configPath))
				configWrapper.ConfigReloaded()
				break
			case err := <-watcherForConfigFile.Error:
				log.Error("Error: %+v", err)
				break
			}
		}
	}()

	err = watcherForConfigFile.Watch(configPath)
	CheckError(err)
}

// NetworkName returns the SSID of the wifi network.
func NetworkName(nif string) string {
	if nif == "" {
		nif = C.GoString(C.guessWifiInterfaceName())
	}

	if nif == "" {
		log.Debug("Could not find Wi-Fi network interface")
		return ""
	}

	active := C.getWifiActive(C.CString(nif))
	powerOn := C.getWifiPowerOn(C.CString(nif))

	if !active {
		log.Debug("Wi-Fi network interface is not active")
		return ""
	}

	if !powerOn {
		log.Debug("Wi-Fi network interface is not powered on")
		return ""
	}

	ssid := C.GoString(C.getWifiSSID(C.CString(nif)))

	if ssid == "" {
		log.Error("Wi-Fi network interface ssid empty")
	}

	return ssid
}

func (session *Session) render(asset string) error {
	asset = "assets/templates/" + asset

	var t *template.Template

	c, ok := session.Config.Cache["template:"+asset]
	if !ok {
		log.Trace("Loading asset: %s", asset)
		a, err := session.Config.AssetLoader(asset)
		log.Trace("Creating template: %s", asset)
		t = template.New(asset)
		t.Delims(session.Config.LeftDelim, session.Config.RightDelim)
		if err != nil || a == nil {
			log.Error("Failed loading template %s: %s", asset, err)
			return err
		}
		log.Trace("Parsing template: %s", asset)
		_, err = t.Parse(string(a))
		if err != nil {
			log.Error("Failed parsing template %s: %s", asset, err)
			return err
		}
		log.Trace("Template parsed successfully: %s", asset)
		session.Config.Cache["template:"+asset] = t
	} else {
		t = c.(*template.Template)
		log.Trace("Template loaded from cache: %s", asset)
	}

	var b bytes.Buffer
	err := t.Execute(&b, session.Stash)
	if err != nil {
		log.Error("Failed executing template %s: %s", asset, err)
		return err
	}

	_, err = session.Response.Write(b.Bytes())

	if err != nil {
		log.Error("Error writing output for template %s: %s", asset, err)
		return err
	}

	return nil
}

func (session *Session) RenderException(status int, err error) {
	key := uuid.NewUUID().String()
	session.Response.Status = status
	session.Stash["Gotcha"].(map[string]interface{})["Error"] = err.Error()
	session.Stash["Gotcha"].(map[string]interface{})["ErrorId"] = key

	buf := make([]byte, 1<<16)
	n := runtime.Stack(buf, true)
	session.Stash["Gotcha"].(map[string]interface{})["Stack"] = fmt.Sprintf("%s", buf[:n])

	log.Error("Exception %s: %s\n%s", key, err.Error(), session.Stash["Gotcha"].(map[string]interface{})["Stack"])

	e := session.render("error.html")
	if e != nil {
		log.Error("Error rendering error page: %s", e)
		session.Response.Write([]byte("[" + key + "] Internal Server Error: " + err.Error() + "\n"))
	}
}

func (session *Session) RenderNotFound() {
	session.Stash["Gotcha"].(map[string]interface{})["Error"] = "Not found"
	session.Response.Status = 404

	e := session.render("notfound.html")
	if e != nil {
		log.Error("Error rendering not found page: %s", e)
	}
}

func RemoveModule(index string, source *Source, author *Author, pkg *Package) {
	out, err := os.OpenFile(index, os.O_RDWR|os.O_APPEND|os.O_CREATE, 0660)
	if err != nil {
		log.Error("Error opening index: %s", err.Error())
		return
	}

	out.Write([]byte(source.Name + " [" + source.URL + "]\n"))
	out.Write([]byte(" " + author.Name + " [" + author.URL + "]\n"))
	out.Write([]byte("  -" + pkg.Name + " => " + pkg.URL + "\n"))

	out.Close()
}

func LoadConfig(global string, workspaces []string) {
	// Load global environment
	log.Info("Loading global environment file: %s", global)
	cfg, err := LoadConfigFile(global)
	if err != nil {
		log.Error("Error loading global configuration: %s", err.Error())
	}
	if cfg != nil {
		GlobalConfigWorkspace = cfg
	}

	// Load workspaces
	for _, conf := range workspaces {
		log.Info("Loading workspace file: %s", conf)
		cfg, err := LoadConfigFile(conf)
		if err != nil {
			log.Error("Error loading workspace: %s", err.Error())
		}
		if cfg != nil {
			ConfigWorkspaces[cfg.Name] = cfg
		}
	}
}

func AppendToIndex(index string, source *Source, author *Author, pkg *Package) {
	out, err := os.OpenFile(index, os.O_RDWR|os.O_APPEND|os.O_CREATE, 0660)
	if err != nil {
		log.Error("Error opening index: %s", err.Error())
		return
	}

	out.Write([]byte(source.Name + " [" + source.URL + "]\n"))
	out.Write([]byte(" " + author.Name + " [" + author.URL + "]\n"))
	out.Write([]byte("  " + pkg.Name + " => " + pkg.URL + "\n"))
	for p, pk := range pkg.Provides {
		out.Write([]byte("   " + p + " (" + pk.Version + "): " + pk.File + "\n"))
	}

	out.Close()
}

func HasJSONXS() bool {
	cmd := exec.Command("perl", "-MJSON::XS", "-e", "")

	_, err := cmd.Output()
	if err != nil {
		log.Error("Error executing command: %s", err)
		return false
	}

	ps := cmd.ProcessState
	sy := ps.Sys().(syscall.WaitStatus)
	exit := sy.ExitStatus()

	if exit != 0 {
		return false
	}

	return true
}

func ParseCPANLine(line string) (*Dependency, error) {
	if len(line) == 0 {
		return nil, nil
	}

	matches := re.FindStringSubmatch(line)
	if len(matches) == 0 {
		log.Trace("Unable to parse line: %s", line)
		return nil, nil
	}

	module := matches[2]
	version := strings.Replace(matches[4], " ", "", -1)
	comment := matches[5]

	dependency, err := DependencyFromString(module, version)

	if strings.HasPrefix(strings.Trim(comment, " "), "# REQS: ") {
		comment = strings.TrimPrefix(strings.Trim(comment, " "), "# REQS: ")
		log.Trace("Found additional dependencies: %s", comment)
		for _, req := range strings.Split(comment, ";") {
			req = strings.Trim(req, " ")
			bits := strings.Split(req, "-")
			new_dep, err := DependencyFromString(bits[0], bits[1])
			if err != nil {
				log.Error("Error parsing REQS dependency: %s", req)
				continue
			}
			log.Trace("Added dependency: %s", new_dep)
			dependency.Additional = append(dependency.Additional, new_dep)
		}
	}

	if err != nil {
		return nil, err
	}

	log.Info("%s (%s %s)", module, dependency.Modifier, dependency.Version)

	return dependency, err
}

func (s *Source) Load() error {
	log.Debug("Loading source: %s", s)

	switch s.Type {
	case "CPAN":
		log.Debug("=> Got CPAN source")
		return s.loadCPANSource()
	case "BackPAN":
		log.Debug("=> Got BackPAN source")
		return s.loadBackPANSource()
	case "SmartPAN":
		log.Debug("=> Got SmartPAN source")
		return nil
	case "MetaCPAN":
		log.Debug("=> Got MetaCPAN source")
		return nil
	default:
		log.Error("Unrecognised source type: %s", s.Type)
		return errors.New(fmt.Sprintf("Unrecognised source: %s", s))
	}
}

func HasPerl() (bool, string) {
	cmd := exec.Command("perl", "-V::version:")

	out, err := cmd.Output()
	if err != nil {
		log.Error("Error executing command: %s", err)
		return false, ""
	}

	ps := cmd.ProcessState
	sy := ps.Sys().(syscall.WaitStatus)
	exit := sy.ExitStatus()

	if exit != 0 {
		return false, ""
	}

	s := string(out)
	s = strings.TrimSpace(s)
	l := strings.Split(s, "\n")
	v := l[0]

	return true, v
}

func main() {
	config = getpan.Configure()
	config.Dump()

	mods := flag.Args()

	if len(mods) == 0 {
		if _, err := os.Stat(config.CPANFile); os.IsNotExist(err) {
			log.Error("cpanfile not found: %s", config.CPANFile)
			os.Exit(1)
		}
	}

	if len(mods) > 0 && mods[0] == "exec" {
		log.Debug("getpan exec => " + strings.Join(mods[1:], " "))

		cmd := exec.Command(mods[1], mods[2:]...)

		cmd.Env = os.Environ()
		cmd.Env = append(cmd.Env, "PERL5LIB="+config.InstallDir+"/lib/perl5")
		cmd.Env = append(cmd.Env, "PATH="+os.Getenv("PATH")+":"+config.InstallDir+"/bin")

		cmd.Stdout = os.Stdout
		cmd.Stderr = os.Stderr

		err := cmd.Run()

		if err != nil {
			// debug so it doesn't show up in stdout/stderr unless -loglevel is used
			log.Debug("Error in exec: %s", err.Error())
			os.Exit(10)
		}

		return
	}

	for _, source := range config.Sources {
		err := source.Load()
		if err != nil {
			log.Error("Error loading sources: %s", err)
			os.Exit(1)
			return
		}
	}

	var deps *getpan.DependencyList

	if len(mods) == 0 {
		log.Info("Installing from cpanfile: %s", config.CPANFile)
		d, err := getpan.ParseCPANFile(config.CPANFile)
		if err != nil {
			log.Error("Error parsing cpanfile: %s", err)
			os.Exit(2)
			return
		}
		deps = &d.DependencyList
	} else {
		log.Info("Installing from command line args")
		deps = &getpan.DependencyList{
			Dependencies: make([]*getpan.Dependency, 0),
		}
		for _, arg := range mods {
			dependency, err := getpan.DependencyFromString(arg, "")
			if err != nil {
				log.Error("Unable to parse input: %s", arg)
				continue
			}
			deps.AddDependency(dependency)
		}
	}

	err := deps.Resolve()
	if err != nil {
		log.Error("Error resolving dependencies: %s", err)
		os.Exit(3)
		return
	}

	if false == config.NoDepdump {
		log.Info("Resolved dependency tree:")
		deps.PrintDeps(0)
	}

	if config.NoInstall {
		log.Info("Skipping installation phase")
		return
	}

	_, err = deps.Install()

	if err != nil {
		log.Error("Error installing dependencies: %s", err)
		os.Exit(4)
		return
	}

	// FIXME hacky, need a better way of tracking installed deps
	log.Info("Successfully installed %d modules", deps.UniqueInstalled())
}

func (m *Module) Install() (int, error) {
	log.Debug("Installing module: %s", m)

	n := 0

	if m.Deps != nil {
		log.Trace("Installing module dependencies for %s", m)

		<-install_semaphore
		o, err := m.Deps.Install()
		install_semaphore <- 1

		n += o
		if err != nil {
			log.Error("Error installing module dependencies for %s: %s", m, err)
			return n, err
		}
	}

	var c *exec.Cmd
	var stdout *bytes.Buffer
	var stderr *bytes.Buffer

	cpanm_cache_dir, err := filepath.Abs(config.CacheDir)
	if err != nil {
		log.Error("Failed to get absolute path of gopan cache directory: %s", err)
		return n, err
	}

	os.Setenv("PERL_CPANM_HOME", cpanm_cache_dir)

	done := false
	attempts := 0
	for !done {
		time.Sleep(time.Duration(100) * time.Millisecond)

		c = m.getCmd()
		stdout = new(bytes.Buffer)
		stderr = new(bytes.Buffer)
		c.Stderr = stderr
		c.Stdout = stdout

		// brute force cpanm text file busy errors
		attempts++
		if err := c.Start(); err != nil {
			if attempts > 10 {
				log.Error("Error installing module %s: %s", m, err)
				return n, err
			}
		} else {
			done = true
		}
	}

	if err := c.Wait(); err != nil {
		if !strings.HasPrefix(strings.ToLower(stderr.String()), "plenv: cannot rehash:") && !strings.Contains(strings.ToLower(stderr.String()), "text file busy") &&
			!strings.HasPrefix(strings.ToLower(stdout.String()), "plenv: cannot rehash:") && !strings.Contains(strings.ToLower(stdout.String()), "text file busy") {
			log.Error(m.Name + "-" + m.Version + " failed to install")
			log.Error("Error installing %s %s: %s\nSTDERR:\n%sSTDOUT:\n%s", m.Name, m.Version, err, stderr.String(), stdout.String())
			return n, err
		}
	}

	n++

	log.Printf("Installed " + m.Name + " (" + m.Version + ")")
	return n, nil
}

func (tr *TaskRun) Start(exitCh chan int) {
	tr.Started = time.Now()

	stdout, err := tr.Cmd.StdoutPipe()
	if err != nil {
		tr.Error = err
		exitCh <- 1
		return
	}
	stderr, err := tr.Cmd.StderrPipe()
	if err != nil {
		tr.Error = err
		exitCh <- 1
		return
	}

	if len(tr.Stdout) > 0 {
		wr, err := NewFileLogWriter(tr.Stdout)
		if err != nil {
			log.Error("Unable to open file %s: %s", tr.Stdout, err.Error())
			tr.StdoutBuf = NewInMemoryLogWriter()
		} else {
			tr.StdoutBuf = wr
		}
	} else {
		tr.StdoutBuf = NewInMemoryLogWriter()
	}
	if len(tr.Stderr) > 0 {
		wr, err := NewFileLogWriter(tr.Stderr)
		if err != nil {
			log.Error("Unable to open file %s: %s", tr.Stderr, err.Error())
			tr.StderrBuf = NewInMemoryLogWriter()
		} else {
			tr.StderrBuf = wr
		}
	} else {
		tr.StderrBuf = NewInMemoryLogWriter()
	}

	if len(tr.Pwd) > 0 {
		log.Info("Setting pwd: %s", tr.Pwd)
		tr.Cmd.Dir = tr.Pwd
	}

	for k, v := range tr.Environment {
		log.Info("Adding env var %s = %s", k, v)
		tr.Cmd.Env = append(tr.Cmd.Env, k+"="+v)
	}

	err = tr.Cmd.Start()
	if tr.Cmd.Process != nil {
		ev := &Event{time.Now(), fmt.Sprintf("Process %d started: %s", tr.Cmd.Process.Pid, tr.Command)}
		log.Info(ev.Message)
		tr.Events = append(tr.Events, ev)
	}
	if err != nil {
		tr.Error = err
		log.Error(err.Error())
		tr.StdoutBuf.Close()
		tr.StderrBuf.Close()
		exitCh <- 1
		return
	}
	go func() {
		go io.Copy(tr.StdoutBuf, stdout)
		go io.Copy(tr.StderrBuf, stderr)

		tr.Cmd.Wait()

		tr.StdoutBuf.Close()
		tr.StderrBuf.Close()

		log.Trace("STDOUT: %s", tr.StdoutBuf.String())
		log.Trace("STDERR: %s", tr.StderrBuf.String())

		ps := tr.Cmd.ProcessState
		sy := ps.Sys().(syscall.WaitStatus)

		ev := &Event{time.Now(), fmt.Sprintf("Process %d exited with status %d", ps.Pid(), sy.ExitStatus())}
		log.Info(ev.Message)
		tr.Events = append(tr.Events, ev)
		log.Info(ps.String())

		tr.Stopped = time.Now()
		exitCh <- 1
	}()
}

func download(session *http.Session) {
	if _, ok := session.Stash["repo"]; !ok {
		session.RenderNotFound()
		return
	}

	if _, ok := session.Stash["file"]; !ok {
		session.RenderNotFound()
		return
	}

	repo := session.Stash["repo"].(string)
	file := session.Stash["file"].(string)

	if repo == "SmartPAN" {
		if _, ok := filemap[file]; !ok {
			log.Debug("SmartPAN repo - file [%s] not found in any index", file)
			session.RenderNotFound()
			return
		}

		repo = filemap[file]
		log.Debug("SmartPAN repo - file [%s] found in [%s]", file, repo)
	}

	log.Debug("Repo [%s], file [%s]", repo, file)

	nfile := config.CacheDir + "/" + repo + "/" + file

	if _, err := os.Stat(nfile); err != nil {
		log.Debug("File not found on disk, considering readthrough")

		for fn, _ := range indexes {
			log.Debug("Trying file: %s", fn)
			if src, ok := indexes[fn][repo]; ok {
				log.Debug("Found matching repo")
				if strings.HasPrefix(src.URL, "http:") {
					log.Debug("Found HTTP URL, trying: %s", src.URL+"/"+file)

					res, err := nethttp.Get(src.URL + "/" + file)
					if err != nil {
						log.Debug("Error on readthrough: %s", err.Error())
						continue
					}
					defer res.Body.Close()
					b, err := ioutil.ReadAll(res.Body)
					if err != nil {
						log.Debug("Error reading body: %s", err.Error())
						continue
					}

					session.Response.Write(b)
					return
				}
			}
		}

		log.Debug("No readthrough available")
		session.RenderNotFound()
		return
	}

	f, err := os.Open(nfile)
	if err != nil {
		log.Error(err.Error())
		session.RenderNotFound()
		return
	}

	defer f.Close()

	b, err := ioutil.ReadAll(f)
	if err != nil {
		log.Error(err.Error())
		session.RenderNotFound()
		return
	}

	session.Response.Write(b)
}

func (m *Module) loadDependencies() error {
	yml, err := ioutil.ReadFile(m.Extracted + "/META.yml")
	if err != nil {
		// TODO this isnt an error (it shouldnt make build fail)
		log.Error("Error opening META.yml for %s: %s", m.Name, err)
		// return nil to prevent build fail
		return nil
	}

	meta := make(map[interface{}]interface{})
	err = yaml.Unmarshal(yml, &meta)
	if err != nil {
		// TODO this isnt a real error, probably
		log.Error("Error parsing YAML: %s", err)
		// return nil to prevent build fail
		return nil
	}

	if reqs, ok := meta["requires"]; ok {
		log.Debug("Found dependencies for module %s", m.Name)
		switch reqs.(type) {
		case map[interface{}]interface{}:
			for req, ver := range reqs.(map[interface{}]interface{}) {
				v := float64(0)
				switch ver.(type) {
				case string:
					v = gopan.VersionFromString(ver.(string))
				case int:
					v = float64(ver.(int))
				}
				log.Printf("=> %s (%f)", req, v)
				dep, err := DependencyFromString(req.(string), fmt.Sprintf("%f", ver))
				if err != nil {
					log.Error("Error parsing dependency: %s", err)
					continue
				}
				if _, ok := perl_core[dep.Name]; ok {
					log.Trace("Module is from perl core: %s", dep.Name)
					continue
				}
				m.Deps.AddDependency(dep)
			}
		}

		log.Debug("Resolving module dependency list")

		if err := m.Deps.Resolve(); err != nil {
			log.Error("Error resolving dependency list [%s]: %s", m.Name, err)
			return err
		}

		return nil
	}

	// FIXME repeat of block above, just with more nested levels
	if p, ok := meta["prereqs"]; ok {
		if r, ok := p.(map[interface{}]interface{})["runtime"]; ok {
			if reqs, ok := r.(map[interface{}]interface{})["requires"]; ok {
				log.Debug("Found dependencies for module %s", m.Name)
				switch reqs.(type) {
				case map[interface{}]interface{}:
					for req, ver := range reqs.(map[interface{}]interface{}) {
						v := float64(0)
						switch ver.(type) {
						case string:
							v = gopan.VersionFromString(ver.(string))
						case int:
							v = float64(ver.(int))
						}
						log.Printf("=> %s (%f)", req, v)
						dep, err := DependencyFromString(req.(string), fmt.Sprintf("%f", ver))
						if err != nil {
							log.Error("Error parsing dependency: %s", err)
							continue
						}
						if _, ok := perl_core[dep.Name]; ok {
							log.Trace("Module is from perl core: %s", dep.Name)
							continue
						}
						m.Deps.AddDependency(dep)
					}
				}
			}
		}
		if t, ok := p.(map[interface{}]interface{})["test"]; ok {
			if reqs, ok := t.(map[interface{}]interface{})["requires"]; ok {
				log.Debug("Found dependencies for module %s", m.Name)
				switch reqs.(type) {
				case map[interface{}]interface{}:
					for req, ver := range reqs.(map[interface{}]interface{}) {
						v := float64(0)
						switch ver.(type) {
						case string:
							v = gopan.VersionFromString(ver.(string))
						case int:
							v = float64(ver.(int))
						}
						log.Printf("=> %s (%f)", req, v)
						dep, err := DependencyFromString(req.(string), fmt.Sprintf("%f", ver))
						if err != nil {
//.........这里部分代码省略.........