/*
  Last Change: 2022-05-16 月 09:34:18.
 */

package main

import (
	"bufio"
    "bytes"
    "compress/gzip"
	"encoding/csv"
	"fmt"
	"io"
	"log"
	"net"
	"net/http"
	"os"
	"path/filepath"
	"sort"
	"strconv"
	"strings"
	"time"
)

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
	indexdb string
	pwdb string
	server_root string
    hhash map[string]hhs
	iymdhash map[string]string
	iyhash map[string]string
	logfile string
)

func init() {
	port = ":3910"
	hhsdb = "hhsdb.csv"
	indexdb = "index.csv"
	pwdb = "passwd"
	logfile = "searcher.log"
}

func main() {
	server_root = filepath.Dir(os.Args[0])
	hhsdb = filepath.Join(server_root, hhsdb)
	indexdb = filepath.Join(server_root, indexdb)
	pwdb = filepath.Join(server_root, pwdb)

	// 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)     // Get /h/0800012345 -> name:addr:20200101#20210701#...
	http.HandleFunc("/hn/", hhsnm_handler)   // Get /hn/0800012345:0800098765:... -> name1:name2:...
	http.HandleFunc("/ht/", hhstm_handler)   // Get /ht/ -> 2020-03-14 12:34 (2020-04-02)
	http.HandleFunc("/ha/", hhsdb_handler)   // Get /ha/ -> hhsdb.csv for Mover
	http.HandleFunc("/i/",  image_handler)   // Get /i/20200110/0800012345.tgz
	http.HandleFunc("/r/",  recent_handler)  // Get /r/0800012345:0800067890:0800099999:... -> 0800012345,name1,20200101:0800067890,name2,20210405:...
	http.HandleFunc("/d/",  index_handler)   // Get /d/ -> index.csv, /d/20xx -> 20xx0401:20xx0408:... , /d/20xx0401 -> 0800012345:0800098765:...
	http.HandleFunc("/dt/", indextm_handler) // Get /dt/ -> 2020-03-14 12:34 (2020-04-02)
	http.HandleFunc("/hd/", hhsdbidx_handler)// Get /hd/ -> 20010401,0800012345,name1\n20010401,0300011111,name2\n...
	http.HandleFunc("/ud/", upidx_handler)   // Get /ud/20200402
	http.HandleFunc("/u/",  uphhsdb_handler) // POST /u/
	http.HandleFunc("/ui/", upimage_handler) // POST /ui/20200401/0800012345.tgz
	http.HandleFunc("/ci/", climage_handler) // Get /ci/20200402 -> remove dir
	http.HandleFunc("/pw/", pw_handler)      // Get /pw/ -> id1:pw1:id2:pw2:...

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

/** FUNCTIONS **/
func loadDB() error {
	hhash = make(map[string]hhs)
	iymdhash = make(map[string]string)
	iyhash = make(map[string]string)

	b, err := os.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 = os.ReadFile(indexdb)
	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
}

func write_errlog(no int, msg string) {
	log := filepath.Join(server_root, logfile)
	t := time.Now().Format("2006-01-02 15:04")
	msg = fmt.Sprintf("%s [%02d] %s\n", t, no, msg)
	f, _ := os.OpenFile(log, os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0644)
	f.Write([]byte(msg))
	f.Close()
}

/** HTTP HANDLERS **/
/* Get /h/0800012345 -> name:addr:20200101#20210701#... */
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 /hn/0800012345:0800098765:... -> name1:name2:... */
func hhsnm_handler(w http.ResponseWriter, r *http.Request) {
	hnolist := strings.Split(r.URL.Path[len("/hn/"):], ":")
	var buf []string
	for _, hno := range hnolist {
		var n string
		if h, ok := hhash[hno]; ok {
			n = h.Name
		}
		buf = append(buf, n)
	}
	w.Write([]byte(strings.Join(buf, ":")))
}

/* Get /ht/ -> 2020-03-14 12:34 (2020-04-02) */
func hhstm_handler(w http.ResponseWriter, r *http.Request) {
	date := ""
	if fi, err := os.Stat(hhsdb); err == nil {
		t := fi.ModTime()
		latest := "0000000001"

		f, _ := os.Open(hhsdb)
		defer f.Close()
		input := bufio.NewScanner(f)
		for input.Scan() {
			s := strings.Split(input.Text(), ",")
			if (strings.Compare(s[0], latest) > 0) {
				latest = s[0]
			}
		}

		latest = "(" + latest + ")"
		date = t.Format("2006-01-02 15:04 ") + latest
	}
	w.Write([]byte(date))
}

/* Get /ha/ -> hhsdb.csv for Mover */
func hhsdb_handler(w http.ResponseWriter, r *http.Request) {
	b, _ := os.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(server_root, "images", filepath.FromSlash(file))

	f, err := os.Open(file)
	if err != nil {
		write_errlog(1, "cannot open " + file)
		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:... -> 0800012345,name1,20200101:0800067890,name2,20210405:... */
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/ -> index.csv, /d/20xx -> 20xx0401:20xx0408:... , /d/20xx0401 -> 0800012345:0800098765:... */
func index_handler(w http.ResponseWriter, r *http.Request) {
	ymd := r.URL.Path[len("/d/"):]

	if len(ymd) == 0 {
		b, _ := os.ReadFile(indexdb)
		w.Write(b)
		return
	}

	var buf string
	if len(ymd) == 4 {
		buf = iyhash[ymd]
	} else if len(ymd) == 8 {
		buf = iymdhash[ymd]
	}
	w.Write([]byte(buf[1:]))
}

/* POST /u/ */
func uphhsdb_handler(w http.ResponseWriter, r *http.Request) {
	if r.Method != http.MethodPost {
		write_errlog(10, "not post method")
		http.NotFound(w, r)
		return
	}

	f, err := os.Create(hhsdb)
	if err != nil {
		write_errlog(11, "cannot create " + hhsdb)
		http.NotFound(w, r)
		return
	}
	defer f.Close()

    b, err := io.ReadAll(r.Body)
    r.Body.Close()
	if err != nil {
		write_errlog(12, "cannot read req-body")
		http.NotFound(w, r)
		return
	}

	br := bytes.NewReader(b)
    zr, err := gzip.NewReader(br)
	if err != nil {
		write_errlog(13, "gzip-reader error")
		http.NotFound(w, r)
        return
	}
	n, err := io.Copy(f, zr)

	if err := zr.Close(); err != nil {
		write_errlog(14, "gzip-reader error")
		http.NotFound(w, r)
        return
	}

	w.Write([]byte(fmt.Sprintf("%d bytes are recieved.\n", n)))

	loadDB();
}

/* POST /ui/20200401/0800012345.tgz */
func upimage_handler(w http.ResponseWriter, r *http.Request) {
	if r.Method != http.MethodPost {
		write_errlog(20, "not post method")
		http.NotFound(w, r)
		return
	}

	uri := r.URL.Path[len("/ui/"):]
	ymd := uri[0:8]
	tgz := uri[9:]

	dir := filepath.Join(server_root, "images", ymd)

	if _, err := os.Stat(dir); os.IsNotExist(err) {
		os.Mkdir(dir, 0644)
	}

	file := filepath.Join(server_root, "images", ymd, tgz)
	f, err := os.Create(file)
	if err != nil {
		write_errlog(21, "cannot create " + file)
		http.NotFound(w, r)
		return
	}
	defer f.Close()

	n, err := io.Copy(f, r.Body)
	if err != nil {
		write_errlog(22, "cannot copy req-body")
		http.NotFound(w, r)
		return
	}
	w.Write([]byte(fmt.Sprintf("%d bytes are recieved.\n", n)))
}

/* Get /dt/ -> 2020-03-14 12:34 (2020-04-02) */
func indextm_handler(w http.ResponseWriter, r *http.Request) {
	date := ""
	if fi, err := os.Stat(indexdb); err == nil {
		t := fi.ModTime()
		latest := "20200101"

		f, _ := os.Open(indexdb)
		defer f.Close()
		input := bufio.NewScanner(f)
		for input.Scan() {
			s := strings.Split(input.Text(), ",")
			if (strings.Compare(s[1], latest) > 0) {
				latest = s[1]
			}
		}

		latest = "(" + latest[0:4] + "-" + latest[4:6] + "-" + latest[6:] + ")"
		date = t.Format("2006-01-02 15:04 ") + latest
	}
	w.Write([]byte(date))
}

/* Get /hd/ -> 20010401,0800012345,name1\n20010401,0300011111,name2\n... */
func hhsdbidx_handler(w http.ResponseWriter, r *http.Request) {
	s := ""
	b, err := os.ReadFile(indexdb)
	if err != nil {
		return
	}
	rd := csv.NewReader(strings.NewReader(string(b)))
	for {
		record, err := rd.Read()
		if err == io.EOF {
			break
		}
		if err != nil {
			return
		}
		s += strings.Join([]string{record[1], record[0], hhash[record[0]].Name}, ",")
		s += "\n"
	}
	w.Write([]byte(s))
}

/* Get /ud/20200402  */
func upidx_handler(w http.ResponseWriter, r *http.Request) {
	date := r.URL.Path[len("/ud/"):]
	var buf []string

	f, _ := os.Open(indexdb)
	input := bufio.NewScanner(f)
	for input.Scan() {
		if !strings.HasSuffix(input.Text(), date) {
			buf = append(buf, input.Text())
		}
	}
	f.Close()

	imgdir := filepath.Join(server_root, "images", date)
	files, _ := os.ReadDir(imgdir)
	for _, file := range files {
		i := file.Name()[0:10] + "," + date
		buf = append(buf, i)
	}
	sort.Sort(sort.Reverse(sort.StringSlice(buf)))

	os.Remove(indexdb)

	s := strings.Join(buf, "\n")
	os.WriteFile(indexdb, []byte(s), 0644)

	loadDB();
	w.Write([]byte("update index done."))
}

/* Get /ci/20200402 */
func climage_handler(w http.ResponseWriter, r *http.Request) {
	date := r.URL.Path[len("/ci/"):]
	dir := filepath.Join(server_root, "images", date)
	os.RemoveAll(dir)
}

/* Get /pw/ -> id1:pw1:id2:pw2:... */
func pw_handler(w http.ResponseWriter, r *http.Request) {
    b, err := os.ReadFile(pwdb)
	if err != nil {
		write_errlog(30, "cannot read passwd-file")
		http.NotFound(w, r)
		return
	}
	w.Write([]byte(strings.ReplaceAll(string(b), "\n", ":")))
}