/* webserver.go
 *
 * This is the webserver handler for Pogo, and handles
 * all incoming connections, including authentication.
 */

package main

import (
	"fmt"
	"io/ioutil"
	"log"
	"net/http"

	"github.com/gorilla/mux"
)

// Prints out contents of feed.rss
func RssHandler(w http.ResponseWriter, r *http.Request) {
	w.Header().Set("Content-Type", "application/rss+xml")
	w.WriteHeader(http.StatusOK)
	data, err := ioutil.ReadFile("assets/web/feed.rss")
	if err != nil {
		panic(err)
	}
	w.Header().Set("Content-Length", fmt.Sprint(len(data)))
	fmt.Fprint(w, string(data))
}

// Does the same as above method, only with the JSON feed data
func JsonHandler(w http.ResponseWriter, r *http.Request) {
	w.Header().Set("Content-Type", "application/json")
	w.WriteHeader(http.StatusOK)
	data, err := ioutil.ReadFile("assets/web/feed.json")
	if err != nil {
		panic(err)
	}
	w.Header().Set("Content-Length", fmt.Sprint(len(data)))
	fmt.Fprint(w, string(data))
}

// Serve up homepage
func HomeHandler(w http.ResponseWriter, r *http.Request) {
	data, err := ioutil.ReadFile("assets/web/index.html")

	if err == nil {
		w.Write(data)
	} else {
		w.WriteHeader(500)
		w.Write([]byte("Error500 - " + http.StatusText(500)))
	}
}

// Authenticate user using basic webserver authentication
// @TODO: Replace this with a different for of _more secure_
// authentication that we can POST to instead.
/*
 * Code from stackoverflow by user Timmmm
 * https://stackoverflow.com/questions/21936332/idiomatic-way-of-requiring-http-basic-auth-in-go/39591234#39591234
 */
func BasicAuth(handler http.HandlerFunc) http.HandlerFunc {

	return func(w http.ResponseWriter, r *http.Request) {
		realm := "Login to Pogo admin interface"
		user, pass, ok := r.BasicAuth()

		if !AuthUser(user,pass) || !ok {
			w.Header().Set("WWW-Authenticate", `Basic realm="`+realm+`"`)
			w.WriteHeader(401)
			w.Write([]byte("Unauthorised.\n"))
			return
		}
		handler(w, r)
	}
}

// Handler for serving up admin page
func AdminHandler(w http.ResponseWriter, r *http.Request) {
	data, err := ioutil.ReadFile("assets/web/admin.html")

	if err == nil {
		w.Write(data)
	} else {
		w.WriteHeader(500)
		w.Write([]byte("500 Something went wrong - " + http.StatusText(500)))
	}
}

// Main function that defines routes
func main() {
	// Start the watch() function in generate_rss.go, which
	// watches for file changes and regenerates the feed
	go watch()

	// Define routes
	r := mux.NewRouter()

	// "Static" paths
	r.PathPrefix("/assets/").Handler(http.StripPrefix("/assets/", http.FileServer(http.Dir("assets/web/static"))))
	r.PathPrefix("/download/").Handler(http.StripPrefix("/download/", http.FileServer(http.Dir("podcasts"))))

	// Paths that require specific handlers
	http.Handle("/", r) // Pass everything to gorilla mux
	r.HandleFunc("/", HomeHandler)
	r.HandleFunc("/rss", RssHandler)
	r.HandleFunc("/json", JsonHandler)

	// Authenticated endpoints should be passed to BasicAuth()
	// first
	r.HandleFunc("/admin", BasicAuth(AdminHandler))
	r.HandleFunc("/admin/publish", BasicAuth(CreateEpisode))
	r.HandleFunc("/admin/delete", BasicAuth(RemoveEpisode))
	r.HandleFunc("/admin/css", BasicAuth(CustomCss))

	r.HandleFunc("/setup", ServeSetup)

	// We're live!
	fmt.Println("Listening on port :8000")
	log.Fatal(http.ListenAndServe(":8000", r))
}