package main

import (
	"bytes"
	"encoding/json"
	"fmt"
	"io/ioutil"
	"log"
	"net/http"
	"net/url"
	"os"
	"runtime"
	"strconv"
	"strings"
	"text/template"

	"github.com/alecthomas/kingpin"
	"github.com/go-yaml/yaml"
	"github.com/goji/httpauth"
	"github.com/gorilla/handlers"
	accesslog "github.com/mash/go-accesslog"
)

type Configure struct {
	Conf            *os.File `yaml:"-"`
	Addr            string   `yaml:"addr"`
	Root            string   `yaml:"root"`
	HttpAuth        string   `yaml:"httpauth"`
	Cert            string   `yaml:"cert"`
	Key             string   `yaml:"key"`
	Cors            bool     `yaml:"cors"`
	Theme           string   `yaml:"theme"`
	XHeaders        bool     `yaml:"xheaders"`
	Upload          bool     `yaml:"upload"`
	PlistProxy      string   `yaml:"plistproxy"`
	Title           string   `yaml:"title"`
	Debug           bool     `yaml:"debug"`
	GoogleTrackerId string   `yaml:"google-tracker-id"`
}

type logger struct {
}

func (l logger) Log(record accesslog.LogRecord) {
	log.Printf("%s - %s %d %s", record.Ip, record.Method, record.Status, record.Uri)
}

var (
	defaultPlistProxy = "https://plistproxy.herokuapp.com/plist"
	gcfg              = Configure{}
	l                 = logger{}

	VERSION   = "unknown"
	BUILDTIME = "unknown time"
	GITCOMMIT = "unknown git commit"
	SITE      = "https://github.com/codeskyblue/gohttpserver"
)

func versionMessage() string {
	t := template.Must(template.New("version").Parse(`GoHTTPServer
  Version:        {{.Version}}
  Go version:     {{.GoVersion}}
  OS/Arch:        {{.OSArch}}
  Git commit:     {{.GitCommit}}
  Built:          {{.Built}}
  Site:           {{.Site}}`))
	buf := bytes.NewBuffer(nil)
	t.Execute(buf, map[string]interface{}{
		"Version":   VERSION,
		"GoVersion": runtime.Version(),
		"OSArch":    runtime.GOOS + "/" + runtime.GOARCH,
		"GitCommit": GITCOMMIT,
		"Built":     BUILDTIME,
		"Site":      SITE,
	})
	return buf.String()
}

func parseFlags() error {
	// initial default conf
	gcfg.Theme = "black"
	gcfg.PlistProxy = defaultPlistProxy
	gcfg.GoogleTrackerId = "UA-81205425-2"
	gcfg.Title = "Go HTTP File Server"

	kingpin.HelpFlag.Short('h')
	kingpin.Version(versionMessage())
	kingpin.Flag("conf", "config file path, yaml format").FileVar(&gcfg.Conf)
	kingpin.Flag("root", "root directory").Short('r').Default("./").StringVar(&gcfg.Root)
	kingpin.Flag("addr", "listen address").Short('a').Default(":8000").StringVar(&gcfg.Addr)
	kingpin.Flag("cert", "tls cert.pem path").StringVar(&gcfg.Cert)
	kingpin.Flag("key", "tls key.pem path").StringVar(&gcfg.Key)
	kingpin.Flag("httpauth", "HTTP basic auth (ex: user:pass)").StringVar(&gcfg.HttpAuth)
	kingpin.Flag("theme", "web theme, one of <black|green>").StringVar(&gcfg.Theme)
	kingpin.Flag("upload", "enable upload support").BoolVar(&gcfg.Upload)
	kingpin.Flag("xheaders", "used when behide nginx").BoolVar(&gcfg.XHeaders)
	kingpin.Flag("cors", "enable cross-site HTTP request").BoolVar(&gcfg.Cors)
	kingpin.Flag("debug", "enable debug mode").BoolVar(&gcfg.Debug)
	kingpin.Flag("plistproxy", "plist proxy when server is not https").Short('p').StringVar(&gcfg.PlistProxy)
	kingpin.Flag("title", "server title").StringVar(&gcfg.Title)
	kingpin.Flag("google-tracker-id", "set to empty to disable it").StringVar(&gcfg.GoogleTrackerId)

	kingpin.Parse() // first parse conf

	if gcfg.Conf != nil {
		defer func() {
			kingpin.Parse() // command line priority high than conf
		}()
		ymlData, err := ioutil.ReadAll(gcfg.Conf)
		if err != nil {
			return err
		}
		return yaml.Unmarshal(ymlData, &gcfg)
	}
	return nil
}

func main() {
	if err := parseFlags(); err != nil {
		log.Fatal(err)
	}
	if gcfg.Debug {
		data, _ := yaml.Marshal(gcfg)
		fmt.Printf("--- config ---\n%s\n", string(data))
	}

	ss := NewHTTPStaticServer(gcfg.Root)
	ss.Theme = gcfg.Theme
	ss.Title = gcfg.Title
	ss.GoogleTrackerId = gcfg.GoogleTrackerId
	ss.Upload = gcfg.Upload

	if gcfg.PlistProxy != "" {
		u, err := url.Parse(gcfg.PlistProxy)
		if err != nil {
			log.Fatal(err)
		}
		u.Scheme = "https"
		ss.PlistProxy = u.String()
	}

	var hdlr http.Handler = ss

	hdlr = accesslog.NewLoggingHandler(hdlr, l)

	// HTTP Basic Authentication
	userpass := strings.SplitN(gcfg.HttpAuth, ":", 2)
	if len(userpass) == 2 {
		user, pass := userpass[0], userpass[1]
		hdlr = httpauth.SimpleBasicAuth(user, pass)(hdlr)
	}
	// CORS
	if gcfg.Cors {
		hdlr = handlers.CORS()(hdlr)
	}
	if gcfg.XHeaders {
		hdlr = handlers.ProxyHeaders(hdlr)
	}

	http.Handle("/", hdlr)
	http.HandleFunc("/-/sysinfo", func(w http.ResponseWriter, r *http.Request) {
		w.Header().Set("Content-Type", "application/json")
		data, _ := json.Marshal(map[string]interface{}{
			"version": VERSION,
		})
		w.Write(data)
	})

	if !strings.Contains(gcfg.Addr, ":") {
		gcfg.Addr = ":" + gcfg.Addr
	}
	log.Printf("listening on %s\n", strconv.Quote(gcfg.Addr))

	var err error
	if gcfg.Key != "" && gcfg.Cert != "" {
		err = http.ListenAndServeTLS(gcfg.Addr, gcfg.Cert, gcfg.Key, nil)
	} else {
		err = http.ListenAndServe(gcfg.Addr, nil)
	}
	log.Fatal(err)
}