package main

import (
	// Standard
	"crypto/md5"
	"encoding/hex"
	"path/filepath"
	"flag"
	"fmt"
	"html/template"
	"io"
	"log"
	"net/http"
	"os"
	"path"
	"regexp"
	"strings"
	"strconv"
	"time"
	_ "embed"
)

const VERSION = "v0.1.2";
const LISTEN_HOST = "0.0.0.0";
const DB_SCHEMA = 5

var (
	flagPort int
	connectionManager ConnectionManager
	static http.Handler
	config Config
)


func init() {// {{{
	flag.IntVar(
		&flagPort,
		"port",
		1371,
		"TCP port to listen on",
	)

	flag.Parse()

	if false {
		time.Sleep(time.Second*1)
	}
}// }}}
func main() {// {{{
	var err error
	log.Printf("\x1b[32mNotes\x1b[0m %s\n", VERSION)

	config, err = ConfigRead(os.Getenv("HOME")+"/.config/notes.yaml")
	if err != nil {
		fmt.Printf("%s\n", err)
		os.Exit(1)
	}

	if err = dbInit(); err != nil {
		fmt.Printf("%s\n", err)
		os.Exit(1)
	}

	connectionManager = NewConnectionManager()
	go connectionManager.BroadcastLoop()

	static = http.FileServer(http.Dir(config.Application.Directories.Static))
	http.HandleFunc("/css_updated", cssUpdateHandler)
	http.HandleFunc("/session/create", sessionCreate)
	http.HandleFunc("/session/retrieve", sessionRetrieve)
	http.HandleFunc("/session/authenticate", sessionAuthenticate)
	http.HandleFunc("/node/tree",     nodeTree)
	http.HandleFunc("/node/retrieve", nodeRetrieve)
	http.HandleFunc("/node/create",   nodeCreate)
	http.HandleFunc("/node/update",   nodeUpdate)
	http.HandleFunc("/node/rename",   nodeRename)
	http.HandleFunc("/node/delete",   nodeDelete)
	http.HandleFunc("/node/upload",   nodeUpload)
	http.HandleFunc("/ws", websocketHandler)
	http.HandleFunc("/", staticHandler)

	listen := fmt.Sprintf("%s:%d", LISTEN_HOST, flagPort)
	log.Printf("\x1b[32mNotes\x1b[0m Listening on %s\n", listen)
	log.Printf("\x1b[32mNotes\x1b[0m Answer for domains %s\n", strings.Join(config.Websocket.Domains, ", "))
	http.ListenAndServe(listen, nil)
}// }}}

func cssUpdateHandler(w http.ResponseWriter, r *http.Request) {// {{{
	log.Println("[BROADCAST] CSS updated")
	connectionManager.Broadcast(struct{ Ok bool; ID string; Op string }{ Ok: true, Op: "css_reload" })
}// }}}
func websocketHandler(w http.ResponseWriter, r *http.Request) {// {{{
	var err error

	_, err = connectionManager.NewConnection(w, r)
	if err != nil {
		log.Printf("[Connection] %s\n", err)
		return
	}
}// }}}
func staticHandler(w http.ResponseWriter, r *http.Request) {// {{{
	data := struct{
		VERSION string
	}{
		VERSION: VERSION,
	}

	// URLs with pattern /(css|images)/v1.0.0/foobar are stripped of the version.
	// To get rid of problems with cached content in browser on a new version release,
	// while also not disabling cache altogether.
	log.Printf("static: %s", r.URL.Path)
	rxp := regexp.MustCompile("^/(css|images|js|fonts)/v[0-9]+\\.[0-9]+\\.[0-9]+/(.*)$")
	if comp := rxp.FindStringSubmatch(r.URL.Path); comp != nil {
		r.URL.Path = fmt.Sprintf("/%s/%s", comp[1], comp[2])
		static.ServeHTTP(w, r)
		return
	}

	// Everything else is run through the template system.
	// For now to get VERSION into files to fix caching.
	log.Printf("template: %s", r.URL.Path)
	tmpl, err := newTemplate(r.URL.Path)
	if err != nil {
		if os.IsNotExist(err) {
			w.WriteHeader(404)
		}
		w.Write([]byte(err.Error()))
		return
	}

	if err = tmpl.Execute(w, data); err != nil {
		w.Write([]byte(err.Error()))
	}
}// }}}

func sessionCreate(w http.ResponseWriter, r *http.Request) {// {{{
	log.Println("/session/create")
	session, err := CreateSession()
	if err != nil {
		responseError(w, err)
		return
	}
	responseData(w, map[string]interface{}{
		"OK": true,
		"Session": session,
	})
}// }}}
func sessionRetrieve(w http.ResponseWriter, r *http.Request) {// {{{
	log.Println("/session/retrieve")
	var err error
	var found bool
	var session Session

	if session, found, err = ValidateSession(r, false); err != nil {
		responseError(w, err)
		return
	}

	responseData(w, map[string]interface{}{
		"OK": true,
		"Valid": found,
		"Session": session,
	})
}// }}}
func sessionAuthenticate(w http.ResponseWriter, r *http.Request) {// {{{
	log.Println("/session/authenticate")
	var err error
	var session Session
	var authenticated bool

	// Validate session
	if session, _, err = ValidateSession(r, true); err != nil {
		responseError(w, err)
		return
	}

	req := struct{ Username string; Password string }{}
	if err = parseRequest(r, &req); err != nil {
		responseError(w, err)
		return
	}

	if authenticated, err = session.Authenticate(req.Username, req.Password); err != nil {
		responseError(w, err)
		return
	}

	responseData(w, map[string]interface{}{
		"OK": true,
		"Authenticated": authenticated,
		"Session": session,
	})
}// }}}

func nodeTree(w http.ResponseWriter, r *http.Request) {// {{{
	var err error
	var session Session

	if session, _, err = ValidateSession(r, true); err != nil {
		responseError(w, err)
		return
	}

	req := struct { StartNodeID int }{}
	if err = parseRequest(r, &req); err != nil {
		responseError(w, err)
		return
	}

	nodes, err := session.NodeTree(req.StartNodeID)
	if err != nil {
		responseError(w, err)
		return
	}

	responseData(w, map[string]interface{}{
		"OK": true,
		"Nodes": nodes,
	})
}// }}}
func nodeRetrieve(w http.ResponseWriter, r *http.Request) {// {{{
	log.Println("/node/retrieve")
	var err error
	var session Session

	if session, _, err = ValidateSession(r, true); err != nil {
		responseError(w, err)
		return
	}

	req := struct { ID int }{}
	if err = parseRequest(r, &req); err != nil {
		responseError(w, err)
		return
	}

	node, err := session.Node(req.ID)
	if err != nil {
		responseError(w, err)
		return
	}

	responseData(w, map[string]interface{}{
		"OK": true,
		"Node": node,
	})
}// }}}
func nodeCreate(w http.ResponseWriter, r *http.Request) {// {{{
	log.Println("/node/create")
	var err error
	var session Session

	if session, _, err = ValidateSession(r, true); err != nil {
		responseError(w, err)
		return
	}

	req := struct {
		Name string
		ParentID int
	}{}
	if err = parseRequest(r, &req); err != nil {
		responseError(w, err)
		return
	}

	node, err := session.CreateNode(req.ParentID, req.Name)
	if err != nil {
		responseError(w, err)
		return
	}

	responseData(w, map[string]interface{}{
		"OK": true,
		"Node": node,
	})
}// }}}
func nodeUpdate(w http.ResponseWriter, r *http.Request) {// {{{
	var err error
	var session Session

	if session, _, err = ValidateSession(r, true); err != nil {
		responseError(w, err)
		return
	}

	req := struct {
		NodeID int
		Content string
	}{}
	if err = parseRequest(r, &req); err != nil {
		responseError(w, err)
		return
	}

	err = session.UpdateNode(req.NodeID, req.Content)
	if err != nil {
		responseError(w, err)
		return
	}

	responseData(w, map[string]interface{}{
		"OK": true,
	})
}// }}}
func nodeRename(w http.ResponseWriter, r *http.Request) {// {{{
	var err error
	var session Session

	if session, _, err = ValidateSession(r, true); err != nil {
		responseError(w, err)
		return
	}

	req := struct {
		NodeID int
		Name string
	}{}
	if err = parseRequest(r, &req); err != nil {
		responseError(w, err)
		return
	}

	err = session.RenameNode(req.NodeID, req.Name)
	if err != nil {
		responseError(w, err)
		return
	}

	responseData(w, map[string]interface{}{
		"OK": true,
	})
}// }}}
func nodeDelete(w http.ResponseWriter, r *http.Request) {// {{{
	var err error
	var session Session

	if session, _, err = ValidateSession(r, true); err != nil {
		responseError(w, err)
		return
	}

	req := struct {
		NodeID int
	}{}
	if err = parseRequest(r, &req); err != nil {
		responseError(w, err)
		return
	}

	err = session.DeleteNode(req.NodeID)
	if err != nil {
		responseError(w, err)
		return
	}

	responseData(w, map[string]interface{}{
		"OK": true,
	})
}// }}}
func nodeUpload(w http.ResponseWriter, r *http.Request) {// {{{
	log.Println("/node/upload")
	var err error
	var session Session

	if session, _, err = ValidateSession(r, true); err != nil {
		responseError(w, err)
		return
	}

	// Parse our multipart form, 10 << 20 specifies a maximum
	// upload of 10 MB files.
	r.Body = http.MaxBytesReader(w, r.Body, 128<<20+512)
	r.ParseMultipartForm(128 << 20)

	// FormFile returns the first file for the given key `myFile`
	// it also returns the FileHeader so we can get the Filename,
	// the Header and the size of the file
	file, handler, err := r.FormFile("file")
	if err != nil {
		responseError(w, err)
		return
	}
	defer file.Close()

	// Read metadata of file for database, and also file contents
	// for MD5, which is used to store the file on disk.
	fileBytes, err := io.ReadAll(file)
	if err != nil {
		responseError(w, err)
		return
	}
	md5sumBytes := md5.Sum(fileBytes)
	md5sum := hex.EncodeToString(md5sumBytes[:])


	var nodeID int
	if nodeID, err = strconv.Atoi(r.PostFormValue("NodeID")); err != nil {
		responseError(w, err)
		return
	}
	nodeFile := File{
		NodeID: nodeID,
		Filename: handler.Filename,
		Size: handler.Size,
		MIME: handler.Header.Get("Content-Type"),
		MD5: md5sum,
	}
	if err = session.AddFile(&nodeFile); err != nil {
		responseError(w, err)
		return
	}

	// Files are stored in a directory structure composed of
	// the first three characters in the md5sum, which is statistically
	// distributed by design, making sure there aren't too many files in
	// a single directory.
	path := filepath.Join(
		config.Application.Directories.Upload,
		md5sum[0:1],
		md5sum[1:2],
		md5sum[2:3],
	)
	if err = os.MkdirAll(path, 0755); err != nil {
		responseError(w, err)
		return
	}

	path = filepath.Join(
		config.Application.Directories.Upload,
		md5sum[0:1],
		md5sum[1:2],
		md5sum[2:3],
		md5sum,
	)
	if err = os.WriteFile(path, fileBytes, 0644); err != nil {
		responseError(w, err)
		return
	}

	responseData(w, map[string]interface{}{
		"OK": true,
		"File": nodeFile,
	})
}// }}}
func nodeFiles(w http.ResponseWriter, r *http.Request) {// {{{
	var err error
	var session Session
	var files []File

	if session, _, err = ValidateSession(r, true); err != nil {
		responseError(w, err)
		return
	}

	req := struct {
		NodeID int
	}{}
	if err = parseRequest(r, &req); err != nil {
		responseError(w, err)
		return
	}

	files, err = session.Files(req.NodeID)
	if err != nil {
		responseError(w, err)
		return
	}

	responseData(w, map[string]interface{}{
		"OK": true,
		"Files": files,
	})
}// }}}

func newTemplate(requestPath string) (tmpl *template.Template, err error) {// {{{
	// Append index.html if needed for further reading of the file
	p := requestPath
	if p[len(p)-1] == '/' {
		p += "index.html"
	}
	p = config.Application.Directories.Static + p

	base := path.Base(p)
	if tmpl, err = template.New(base).ParseFiles(p); err != nil { return }

	return
}// }}}

// vim: foldmethod=marker