package main

import (
	"encoding/json"
	"log"
	"net/http"
	"pkg/directory"
	"pkg/storage"
	"strconv"
	"strings"
)

func init() {
	cmdMaster.Run = runMaster // break init cycle
	IsDebug = cmdMaster.Flag.Bool("debug", false, "enable debug mode")
}

var cmdMaster = &Command{
	UsageLine: "master -port=9333",
	Short:     "start a master server",
	Long: `start a master server to provide volume=>location mapping service
  and sequence number of file ids

  `,
}

var (
	mport             = cmdMaster.Flag.Int("port", 9333, "http listen port")
	metaFolder        = cmdMaster.Flag.String("mdir", "/tmp", "data directory to store mappings")
	capacity          = cmdMaster.Flag.Int("capacity", 100, "maximum number of volumes to hold")
	mapper            *directory.Mapper
	volumeSizeLimitMB = cmdMaster.Flag.Uint("volumeSizeLimitMB", 32*1024, "Default Volume Size in MegaBytes")
)

func dirLookupHandler(w http.ResponseWriter, r *http.Request) {
	vid := r.FormValue("volumeId")
	commaSep := strings.Index(vid, ",")
	if commaSep > 0 {
		vid = vid[0:commaSep]
	}
	volumeId, _ := storage.NewVolumeId(vid)
	machine, e := mapper.Get(volumeId)
	if e == nil {
		writeJson(w, r, map[string]string{"url": machine.Url, "publicUrl": machine.PublicUrl})
	} else {
		log.Println("Invalid volume id", volumeId)
		writeJson(w, r, map[string]string{"error": "volume id " + volumeId.String() + " not found"})
	}
}
func dirAssignHandler(w http.ResponseWriter, r *http.Request) {
	c := r.FormValue("count")
	fid, count, machine, err := mapper.PickForWrite(c)
	if err == nil {
		writeJson(w, r, map[string]interface{}{"fid": fid, "url": machine.Url, "publicUrl": machine.PublicUrl, "count": count})
	} else {
		writeJson(w, r, map[string]interface{}{"error": err})
	}
}
func dirJoinHandler(w http.ResponseWriter, r *http.Request) {
	s := r.RemoteAddr[0:strings.Index(r.RemoteAddr, ":")+1] + r.FormValue("port")
	publicUrl := r.FormValue("publicUrl")
	volumes := new([]storage.VolumeInfo)
	json.Unmarshal([]byte(r.FormValue("volumes")), volumes)
	if *IsDebug {
		log.Println(s, "volumes", r.FormValue("volumes"))
	}
	mapper.Add(directory.NewMachine(s, publicUrl, *volumes))
}
func dirStatusHandler(w http.ResponseWriter, r *http.Request) {
	writeJson(w, r, mapper)
}

func runMaster(cmd *Command, args []string) bool {
	log.Println("Volume Size Limit is", *volumeSizeLimitMB, "MB")
	mapper = directory.NewMapper(*metaFolder, "directory", uint64(*volumeSizeLimitMB)*1024*1024)
	http.HandleFunc("/dir/assign", dirAssignHandler)
	http.HandleFunc("/dir/lookup", dirLookupHandler)
	http.HandleFunc("/dir/join", dirJoinHandler)
	http.HandleFunc("/dir/status", dirStatusHandler)

	log.Println("Start directory service at http://127.0.0.1:" + strconv.Itoa(*mport))
	e := http.ListenAndServe(":"+strconv.Itoa(*mport), nil)
	if e != nil {
		log.Fatal("Fail to start:", e)
	}
	return true
}