package main

import (
	"fmt"
	"net/http"
	"os"
	"regexp"
	"strings"
)

var SFU_FILES_DIR string = getEnvvar("SFU_FILES_DIR")
var SFU_PORT string = getEnvvar("SFU_PORT")

func getEnvvar(envvar_name string) string {
	Info.Printf("getting envvar %v\n", envvar_name)
	envvar_value, isSet := os.LookupEnv(envvar_name)
	if !isSet {
		Error.Printf("%v is not set\n", envvar_name)
		os.Exit(1)
	}
	return envvar_value
}

func emptyArray(s []string) []string {
	var r []string
	for _, str := range s {
		if str != "" {
			r = append(r, str)
		}
	}
	return r
}

func routeFiles(w http.ResponseWriter, r *http.Request) {
	path := r.URL.Path
	Info.Printf("received %v on %v", r.Method, path)
	paths := emptyArray(strings.Split(path, "/"))
	Info.Printf("paths %v\n", paths)
	switch len(paths) {
	case 1:
		switch r.Method {
		case http.MethodGet:
			listFiles(w, r)
		case http.MethodPost:
			uploadFile(w, r)
		default:
			http.Error(w, "Method not allowed", http.StatusMethodNotAllowed)
			Warning.Printf("%v not allowed\n", r.Method)
			Error.Printf("will return %v\n", http.StatusMethodNotAllowed)
		}
		return
	case 2:
		switch r.Method {
		case http.MethodGet:
			downloadFile(w, r, paths[1])
		case http.MethodDelete:
			deleteFile(w, r, paths[1])
		default:
			http.Error(w, "Method not allowed", http.StatusMethodNotAllowed)
			Warning.Printf("%v not allowed\n", r.Method)
			Error.Printf("will return %v\n", http.StatusMethodNotAllowed)
		}
	default:
		http.Error(w, "Not found", http.StatusNotFound)
	}

}

func route(w http.ResponseWriter, r *http.Request) {
	path := r.URL.Path
	switch {
	case path == "/":
		fmt.Fprintf(w, "Hello, world!")
	case path == "/health":
		Info.Println("health check OK")
		w.WriteHeader(http.StatusOK)
		w.Write([]byte("OK"))
	case regexp.MustCompile("^/files").MatchString(path):
		Info.Println("received request for files, will call files router")
		routeFiles(w, r)
	default:
		w.WriteHeader(http.StatusNotFound)
	}
}

func main() {
	mux := http.NewServeMux()
	mux.HandleFunc("/", route)
	port := fmt.Sprintf(":%v", SFU_PORT)
	Info.Printf("running SFU on port %v\n", port)
	err := http.ListenAndServe(port, mux)
	if err != nil {
		Error.Printf("%v port may not be available\n", port)
		os.Exit(1)
	}
}