package main

import (
	"fmt"
	"log"
	"net/http"
	"os"
	"text/template"

	"github.com/gorilla/context"
	"github.com/gorilla/mux"
	"github.com/gorilla/sessions"
)

// SiteData is the basic data needed for the site/pages
type SiteData struct {
	Title       string
	SubTitle    string
	Port        int
	SessionName string

	Stylesheets []string
	Scripts     []string

	Flash      flashMessage // Quick message at top of page
	Menu       []menuItem   // Top-aligned menu items
	BottomMenu []menuItem   // Bottom-aligned menu items

	// Any other template data
	TemplateData interface{}
}

type flashMessage struct {
	Message string
	Status  string
}

type menuItem struct {
	Text   string
	Link   string
	Active bool
}

var site SiteData

var sessionStore = sessions.NewCookieStore([]byte("gostatbot secret cookie nobody will guess"))
var r *mux.Router

// This is the main function for the web server
func statWebMain(slack *Slack) {
	site.Title = "stat_bot"
	site.SubTitle = ""
	site.Port = 3000
	site.SessionName = "statbot"

	r = mux.NewRouter()
	r.StrictSlash(true)

	assetHandler := http.FileServer(http.Dir("./assets/"))
	http.Handle("/assets/", http.StripPrefix("/assets/", assetHandler))
	r.HandleFunc("/", handleStats)
	http.Handle("/", r)
	go func() {
		log.Fatal(http.ListenAndServe(fmt.Sprintf(":%d", site.Port), context.ClearHandler(http.DefaultServeMux)))
	}()
}

func initRequest(w http.ResponseWriter, req *http.Request) {
	site.SubTitle = ""
	site.Stylesheets = make([]string, 0, 0)
	site.Stylesheets = append(site.Stylesheets, "/assets/css/pure-min.css")
	site.Stylesheets = append(site.Stylesheets, "/assets/css/statbot.css")
	site.Stylesheets = append(site.Stylesheets, "https://maxcdn.bootstrapcdn.com/font-awesome/4.4.0/css/font-awesome.min.css")

	site.Scripts = make([]string, 0, 0)

	site.Menu = make([]menuItem, 0, 0)
	site.Menu = append(site.Menu, menuItem{Text: "Stats", Link: "/stats/"})

	site.BottomMenu = make([]menuItem, 0, 0)
	site.BottomMenu = append(site.BottomMenu, menuItem{Text: "Admin", Link: "/admin/"})
}

func handleStats(w http.ResponseWriter, req *http.Request) {
	initRequest(w, req)

	setMenuItemActive("Stats")

	showPage("stats.html", site, w)
}

// showPage
// Load a template and all of the surrounding templates
func showPage(tmplName string, tmplData interface{}, w http.ResponseWriter) error {
	for _, tmpl := range []string{
		"htmlheader.html",
		"menu.html",
		"header.html",
		tmplName,
		"footer.html",
		"htmlfooter.html",
	} {
		if err := outputTemplate(tmpl, tmplData, w); err != nil {
			writeToLog(fmt.Sprintf("%s\n", err))
			return err
		}
	}
	return nil
}

// outputTemplate
// Spit out a template
func outputTemplate(tmplName string, tmplData interface{}, w http.ResponseWriter) error {
	_, err := os.Stat("templates/" + tmplName)
	if err == nil {
		t := template.New(tmplName)
		t, _ = t.ParseFiles("templates/" + tmplName)
		return t.Execute(w, tmplData)
	}
	return fmt.Errorf("WebServer: Cannot load template (templates/%s): File not found", tmplName)
}

// setMenuItemActive
// Sets a menu item to active, all others to inactive
func setMenuItemActive(which string) {
	for i := range site.Menu {
		if site.Menu[i].Text == which {
			site.Menu[i].Active = true
		} else {
			site.Menu[i].Active = false
		}
	}
}

func getSessionStringValue(key string, w http.ResponseWriter, req *http.Request) (string, error) {
	session, err := sessionStore.Get(req, site.SessionName)
	if err != nil {
		return "", err
	}
	val := session.Values[key]
	var retVal string
	var ok bool
	if retVal, ok = val.(string); !ok {
		return "", fmt.Errorf("Unable to create string from %s", key)
	}
	return retVal, nil
}

func assertError(err error, w http.ResponseWriter) bool {
	if err != nil {
		http.Error(w, err.Error(), 500)
		return true
	}
	return false
}