package main

import (
	"database/sql"
	"git.sr.ht/~adnano/gmi"
	"github.com/gorilla/handlers"
	_ "github.com/mattn/go-sqlite3"
	"golang.org/x/crypto/bcrypt"
	"html/template"
	"io"
	"io/ioutil"
	"log"
	"net/http"
	"os"
	"path"
	"path/filepath"
	"strings"
	"time"
)

var t *template.Template
var DB *sql.DB

const InternalServerErrorMsg = "500: Internal Server Error"

func renderError(w http.ResponseWriter, errorMsg string, statusCode int) {
	data := struct {
		PageTitle string
		ErrorMsg  string
	}{"Error!", errorMsg}
	err := t.ExecuteTemplate(w, "error.html", data)
	if err != nil { // shouldn't happen probably
		http.Error(w, errorMsg, statusCode)
	}
}

func rootHandler(w http.ResponseWriter, r *http.Request) {
	// serve everything inside static directory
	if r.URL.Path != "/" {
		fileName := path.Join(c.TemplatesDirectory, "static", filepath.Clean(r.URL.Path))
		http.ServeFile(w, r, fileName)
		return
	}
	indexFiles, err := getIndexFiles()
	if err != nil {
		log.Println(err)
		renderError(w, InternalServerErrorMsg, 500)
		return
	}
	allUsers, err := getUsers()
	if err != nil {
		log.Println(err)
		renderError(w, InternalServerErrorMsg, 500)
		return
	}
	data := struct {
		Domain    string
		PageTitle string
		Files     []*File
		Users     []string
	}{c.RootDomain, c.SiteTitle, indexFiles, allUsers}
	err = t.ExecuteTemplate(w, "index.html", data)
	if err != nil {
		log.Println(err)
		renderError(w, InternalServerErrorMsg, 500)
		return
	}
}

func editFileHandler(w http.ResponseWriter, r *http.Request) {
	authUser := "alex"
	fileName := filepath.Clean(r.URL.Path[len("/edit/"):])
	filePath := path.Join(c.FilesDirectory, authUser, fileName)
	if r.Method == "GET" {
		err := checkIfValidFile(filePath, nil)
		if err != nil {
			log.Println(err)
			renderError(w, err.Error(), 400)
			return
		}
		f, err := os.OpenFile(filePath, os.O_RDONLY|os.O_CREATE, 0644)
		defer f.Close()
		fileBytes, err := ioutil.ReadAll(f)
		if err != nil {
			log.Println(err)
			renderError(w, InternalServerErrorMsg, 500)
			return
		}
		data := struct {
			FileName  string
			FileText  string
			PageTitle string
		}{fileName, string(fileBytes), c.SiteTitle}
		err = t.ExecuteTemplate(w, "edit_file.html", data)
		if err != nil {
			log.Println(err)
			renderError(w, InternalServerErrorMsg, 500)
			return
		}
	} else if r.Method == "POST" {
		// get post body
		r.ParseForm()
		fileBytes := []byte(r.Form.Get("file_text"))
		err := checkIfValidFile(filePath, fileBytes)
		if err != nil {
			log.Println(err)
			renderError(w, err.Error(), 400)
			return
		}
		err = ioutil.WriteFile(filePath, fileBytes, 0644)
		if err != nil {
			log.Println(err)
			renderError(w, InternalServerErrorMsg, 500)
			return
		}
		http.Redirect(w, r, "/my_site", 302)
	}
}

func uploadFilesHandler(w http.ResponseWriter, r *http.Request) {
	if r.Method == "POST" {
		authUser := "alex"
		r.ParseMultipartForm(10 << 20)
		file, fileHeader, err := r.FormFile("file")
		fileName := filepath.Clean(fileHeader.Filename)
		defer file.Close()
		if err != nil {
			log.Println(err)
			renderError(w, err.Error(), 400)
			return
		}
		var dest []byte
		file.Read(dest)
		log.Println("asdfadf")
		err = checkIfValidFile(fileName, dest)
		if err != nil {
			log.Println(err)
			renderError(w, err.Error(), 400)
			return
		}
		destPath := path.Join(c.FilesDirectory, authUser, fileName)

		f, err := os.OpenFile(destPath, os.O_WRONLY|os.O_CREATE, 0644)
		if err != nil {
			log.Println(err)
			renderError(w, InternalServerErrorMsg, 500)
			return
		}
		defer f.Close()
		io.Copy(f, file)
	}
	http.Redirect(w, r, "/my_site", 302)
}

func deleteFileHandler(w http.ResponseWriter, r *http.Request) {
	authUser := "alex"
	fileName := filepath.Clean(r.URL.Path[len("/delete/"):])
	filePath := path.Join(c.FilesDirectory, authUser, fileName)
	if r.Method == "POST" {
		os.Remove(filePath) // suppress error
	}
	http.Redirect(w, r, "/my_site", 302)
}

func mySiteHandler(w http.ResponseWriter, r *http.Request) {
	authUser := "alex"
	// check auth
	files, _ := getUserFiles(authUser)
	data := struct {
		Domain    string
		PageTitle string
		AuthUser  string
		Files     []*File
	}{c.RootDomain, c.SiteTitle, authUser, files}
	_ = t.ExecuteTemplate(w, "my_site.html", data)
}

func loginHandler(w http.ResponseWriter, r *http.Request) {
	if r.Method == "GET" {
		// show page
		data := struct {
			Error     string
			PageTitle string
		}{"", "Login"}
		err := t.ExecuteTemplate(w, "login.html", data)
		if err != nil {
			log.Println(err)
			renderError(w, InternalServerErrorMsg, 500)
			return
		}
	} else if r.Method == "POST" {
		r.ParseForm()
		name := r.Form.Get("username")
		password := r.Form.Get("password")
		row := DB.QueryRow("SELECT password_hash FROM user where username = $1", name)
		var db_password []byte
		_ = row.Scan(&db_password)
		if bcrypt.CompareHashAndPassword(db_password, []byte(password)) == nil {
			log.Println("logged in")
			// create session
			http.Redirect(w, r, "/", 302)
		} else {
			data := struct {
				Error     string
				PageTitle string
			}{"Invalid login or password", c.SiteTitle}
			err := t.ExecuteTemplate(w, "login.html", data)
			if err != nil {
				log.Println(err)
				renderError(w, InternalServerErrorMsg, 500)
				return
			}
		}
	}
}

const ok = "-0123456789abcdefghijklmnopqrstuvwxyz"

func isOkUsername(s string) bool {
	if len(s) < 1 {
		return false
	}
	if len(s) > 31 {
		return false
	}
	for _, char := range s {
		if !strings.Contains(ok, strings.ToLower(string(char))) {
			return false
		}
	}
	return true
}
func registerHandler(w http.ResponseWriter, r *http.Request) {
	if r.Method == "GET" {
		data := struct {
			Domain    string
			Errors    []string
			PageTitle string
		}{c.RootDomain, nil, "Register"}
		err := t.ExecuteTemplate(w, "register.html", data)
		if err != nil {
			log.Println(err)
			renderError(w, InternalServerErrorMsg, 500)
			return
		}
	} else if r.Method == "POST" {
		r.ParseForm()
		email := r.Form.Get("email")
		password := r.Form.Get("password")
		errors := []string{}
		if !strings.Contains(email, "@") {
			errors = append(errors, "Invalid Email")
		}
		if r.Form.Get("password") != r.Form.Get("password2") {
			errors = append(errors, "Passwords don't match")
		}
		if len(password) < 6 {
			errors = append(errors, "Password is too short")
		}
		username := strings.ToLower(r.Form.Get("username"))
		if !isOkUsername(username) {
			errors = append(errors, "Username is invalid: can only contain letters, numbers and hypens. Maximum 32 characters.")
		}
		hashedPassword, err := bcrypt.GenerateFromPassword([]byte(password), 8) // TODO handle error
		_, err = DB.Exec("insert into user (username, email, password_hash) values ($1, $2, $3)", username, email, string(hashedPassword))
		if err != nil {
			log.Println(err)
			errors = append(errors, "Username or email is already used")
		}
		if len(errors) > 0 {
			data := struct {
				Domain    string
				Errors    []string
				PageTitle string
			}{c.RootDomain, errors, "Register"}
			t.ExecuteTemplate(w, "register.html", data)
		} else {
			data := struct {
				Domain    string
				Message   string
				PageTitle string
			}{c.RootDomain, "Registration complete! The server admin will approve your request before you can log in.", "Registration Complete"}
			t.ExecuteTemplate(w, "message.html", data)
		}
	}
}

// Server a user's file
func userFile(w http.ResponseWriter, r *http.Request) {
	userName := strings.Split(r.Host, ".")[0]
	fileName := path.Join(c.FilesDirectory, userName, filepath.Clean(r.URL.Path))
	extension := path.Ext(fileName)
	if r.URL.Path == "/static/style.css" {
		http.ServeFile(w, r, path.Join(c.TemplatesDirectory, "static/style.css"))
	}
	if extension == ".gmi" || extension == ".gemini" {
		// covert to html
		stat, _ := os.Stat(fileName)
		file, _ := os.Open(fileName)
		htmlString := gmi.Parse(file).HTML()
		reader := strings.NewReader(htmlString)
		w.Header().Set("Content-Type", "text/html")
		http.ServeContent(w, r, fileName, stat.ModTime(), reader)
	} else {
		http.ServeFile(w, r, fileName)
	}
}

func runHTTPServer() {
	log.Println("Running http server")
	var err error
	t, err = template.ParseGlob(path.Join(c.TemplatesDirectory, "*.html"))
	if err != nil {
		log.Fatal(err)
	}
	serveMux := http.NewServeMux()

	serveMux.HandleFunc(c.RootDomain+"/", rootHandler)
	serveMux.HandleFunc(c.RootDomain+"/my_site", mySiteHandler)
	serveMux.HandleFunc(c.RootDomain+"/edit/", editFileHandler)
	serveMux.HandleFunc(c.RootDomain+"/upload", uploadFilesHandler)
	serveMux.HandleFunc(c.RootDomain+"/login", loginHandler)
	serveMux.HandleFunc(c.RootDomain+"/register", registerHandler)
	serveMux.HandleFunc(c.RootDomain+"/delete/", deleteFileHandler)

	// TODO rate limit login https://github.com/ulule/limiter

	wrapped := handlers.LoggingHandler(os.Stdout, serveMux)

	// handle user files based on subdomain
	serveMux.HandleFunc("/", userFile)
	// login+register functions
	srv := &http.Server{
		ReadTimeout:  5 * time.Second,
		WriteTimeout: 10 * time.Second,
		IdleTimeout:  120 * time.Second,
		Addr:         ":8080",
		// TLSConfig:    tlsConfig,
		Handler: wrapped,
	}
	log.Fatal(srv.ListenAndServe())
}