/*
  Last Change: 2020-04-16 木 17:15:49.
 */

package main

import (
	"encoding/csv"
	"fmt"
	"io"
	"io/ioutil"
	"log"
	"net"
	"net/http"
	"os"
	"path/filepath"
	"strconv"
	"strings"
)

type hhs struct {
	No string
	//Birth string
	Name string
	//Kana string
	Addr string
	//Sex string
	Ccn []string
}

func (h *hhs) GetData() string {
	s := strings.Join(h.Ccn, "#")
	s = strings.Join([]string{h.Name, h.Addr, s}, ":")
	return s
}

func (h *hhs) GetRecent() string {
	ccn := ""
	if len(h.Ccn) > 0 {
		ccn = h.Ccn[0]
	}
	return strings.Join([]string{h.No, h.Name, ccn}, ",")
}

var (
	server string
	port string
	hhsdb string
	img_root string
    hhash map[string]hhs
	iymdhash map[string]string
	iyhash map[string]string
)

func init() {
	port = ":3910"
	hhsdb = "hhsdb.csv"
	img_root = "./images"
	hhash = make(map[string]hhs)
	iymdhash = make(map[string]string)
	iyhash = make(map[string]string)
}

func main() {

	// setting IP-Address & Port
	addrs, err := net.InterfaceAddrs()
	if err != nil {
		log.Fatal(err)
	}
	for _, a := range addrs {
		if ipnet, ok := a.(*net.IPNet); ok && !ipnet.IP.IsLoopback() {
			if strings.HasPrefix(ipnet.IP.String(), "169.254") {
				continue
			}
			if ipnet.IP.To4() != nil {
				server = ipnet.IP.String() + port
			}
		}
	}

	if err := loadDB(); err != nil {
		log.Fatal(err)
	}

	// Http-Handler
	http.HandleFunc("/h/",  hhs_handler)
	http.HandleFunc("/ha/", hhsdb_handler)
	http.HandleFunc("/u/",  uphhsdb_handler)
	http.HandleFunc("/i/",  image_handler)
	http.HandleFunc("/r/",  recent_handler)
	http.HandleFunc("/d/",  index_handler)

	log.Fatal(http.ListenAndServe(server, nil))
}

func loadDB() error {
	b, err := ioutil.ReadFile(hhsdb)
	if err != nil {
		return err
	}
	r := csv.NewReader(strings.NewReader(string(b)))
	for {
		record, err := r.Read()
		if err == io.EOF {
			break
		}
		if err != nil {
			return err
		}
		h := hhs{
			No: record[0],
			//Birth: record[1],
			Name: record[2],
			//Kana: record[3],
			Addr: record[4],
			//Sex: record[5],
		}
		hhash[record[0]] = h
	}

	b, err = ioutil.ReadFile("index.csv")
	if err != nil {
		return err
	}
	r = csv.NewReader(strings.NewReader(string(b)))
	for {
		record, err := r.Read()
		if err == io.EOF {
			break
		}
		if err != nil {
			return err
		}
		h := hhash[record[0]]
		ccn := h.Ccn
		h.Ccn = append(ccn, record[1])
		hhash[record[0]] = h

		iymdhash[record[1]] += ":" + record[0]
	}

	for ymd, _ := range iymdhash {
		y := ymd[0:4]
		if ymd[4:6] == "01" || ymd[4:6] == "02" || ymd[4:6] == "03" {
			yy, _ := strconv.Atoi(y)
			y = fmt.Sprintf("%d", yy - 1)
		}
		iyhash[y] += ":" + ymd
	}

	return nil
}

/* Get /h/0800012345 -> name:addr:ymd1#ymd2#... */
func hhs_handler(w http.ResponseWriter, r *http.Request) {
	hno := r.URL.Path[len("/h/"):]
	s := ""
	if h, ok := hhash[hno]; ok {
		s = h.GetData()
	}
	w.Write([]byte(s))
}

/* Get /ha/ -> hhsdb.csv for Mover */
func hhsdb_handler(w http.ResponseWriter, r *http.Request) {
	b, _ := ioutil.ReadFile(hhsdb)
	w.Write(b)
}

/* Get /i/20200110/0800012345.tgz */
func image_handler(w http.ResponseWriter, r *http.Request) {
	file := r.URL.Path[len("/i/"):]
	file = filepath.Join(img_root, filepath.FromSlash(file))

	f, err := os.Open(file)
	if err != nil {
		http.NotFound(w, r)
		return
	}
	defer f.Close()

	fi, _ := f.Stat()

	w.Header().Set("Content-Type", "rsearcher/octet-stream")
	w.Header().Set("Content-Length", fmt.Sprintf("%d", fi.Size()))
	io.Copy(w, f)
}

/* Get /r/0800012345:0800067890:0800099999:... */
func recent_handler(w http.ResponseWriter, r *http.Request) {
	hnolist := strings.Split(r.URL.Path[len("/r/"):], ":")
	var buf []string
	for _, hno := range hnolist {
		s := hno + ",,"
		if h, ok := hhash[hno]; ok {
			s = h.GetRecent()
			if h.No == "" {
				s = hno + s
			}
		}
		buf = append(buf, s)
	}
	w.Write([]byte(strings.Join(buf, ":")))
}

/* Get /d/20xx -> 20xx0401:2020xx0408:... , /d/20xx0401 -> 0800012345:0800098765:... */
func index_handler(w http.ResponseWriter, r *http.Request) {
	var buf string
	ymd := r.URL.Path[len("/d/"):]
	if len(ymd) == 4 {
		buf = iyhash[ymd]
	}
	if len(ymd) == 8 {
		buf = iymdhash[ymd]
	}
	w.Write([]byte(buf[1:]))
}

func uphhsdb_handler(w http.ResponseWriter, r *http.Request) {
	server_root := filepath.Dir(os.Args[0])
	file := filepath.Join(server_root, "db", hhsdb)
	f, err := os.Create(file)
	if err != nil {
		http.NotFound(w, r)
		return
	}
	n, err := io.Copy(f, r.Body)
	if err != nil {
		http.NotFound(w, r)
		return
	}
	f.Close()
	w.Write([]byte(fmt.Sprintf("%d bytes are recieved.\n", n)))
}