/*
The Kurz Web UI exposes HTTP routes for browsers, route names to access them, and types for the requests.

These routes are exposed by running SetupRoutes(address), which is enough to
configure the Kurz domain API. Be sure to also configure the domain SPI to have
a complete application.
*/
package web

import (
	"html/template"
	"net/http"
	"path/filepath"

	"github.com/gorilla/mux"
)

// Route names.
const (
	RouteGetRoot    = "kurz.web.get_root"
	RouteGetShort   = "kurz.web.get_short"
	RoutePostTarget = "kurz.web.post_target"
)

// Content types.
const (
	// HtmlType is the MIME HTML type.
	HtmlType = "text/html"

	// HtmlTypeRegex is a regex matching the MIME HTML type anywhere
	HtmlTypeRegex = HtmlType
)

var tmpl *template.Template

type Globals struct {
	AssetsVersion               int
	FullyQualifiedAssetsBaseURL string
	FullyQualifiedSiteBaseURL   string
	RefreshDelay                int
	SiteName                    string
}

var globals Globals

// SetupRoutes() configures Web UI routes on the passed mux.Router.
func SetupRoutes(router *mux.Router, configAssetsPath string) {
	const assetsPrefix = "/public"
	absAssetsDir, err := filepath.Abs(configAssetsPath)
	if err != nil {
		panic(err)
	}
	fs := http.FileServer(http.Dir(absAssetsDir))
	router.PathPrefix(assetsPrefix).Handler(http.StripPrefix(assetsPrefix, fs))
	router.Handle("/favicon.ico", fs)

	// BUG(fgm): improve Accept header matchers once https://github.com/golang/go/issues/19307 is completed.
	router.HandleFunc("/{short}", handleGetShort).
		Methods("GET", "HEAD").
		Name(RouteGetShort)
	router.HandleFunc("/", handlePostTarget).
		HeadersRegexp("Accept", HtmlTypeRegex).
		Headers("Content-Type", HtmlType).
		Methods("POST").
		Name(RoutePostTarget)
	router.HandleFunc("/", handleGetRoot).
		Methods("GET", "HEAD").
		Name(RouteGetRoot)

	base, _ := filepath.Abs(configAssetsPath + "/../templates/")
	layout := base + "/layout"
	tmpl = template.Must(template.ParseFiles(
		base+"/201.gohtml",
		base+"/404.gohtml",
		base+"/home.gohtml",
		layout+"/analytics.gohtml",
		layout+"/footer.gohtml",
		layout+"/inlinecss.gohtml",
	))
}

func BuildGlobals(c map[string]interface{}) {
	// Note: keys in viper are lower-cased.
	globals = Globals{
		AssetsVersion:               c["assetsversion"].(int),
		FullyQualifiedAssetsBaseURL: c["fullyqualifiedassetsbaseurl"].(string),
		FullyQualifiedSiteBaseURL:   c["fullyqualifiedsitebaseurl"].(string),
		RefreshDelay:                c["refreshdelay"].(int),
		SiteName:                    c["sitename"].(string),
	}
}