package main

import (
	"context"
	"net/http"

	"github.com/flosch/pongo2"
	"github.com/gorilla/sessions"
	log "github.com/sirupsen/logrus"
)

type httpHelperFunc func(c context.Context, res http.ResponseWriter, r *http.Request, session *sessions.Session, ctx *pongo2.Context) (*string, error)

func httpHelper(f httpHelperFunc) http.HandlerFunc {
	return func(res http.ResponseWriter, r *http.Request) {
		sess, _ := cookieStore.Get(r, "cloudkeys-go")
		ctx := pongo2.Context{}

		if errFlash := sess.Flashes("error"); len(errFlash) > 0 {
			ctx["error"] = errFlash[0].(string)
		}

		c := getContext(r)

		template, err := f(c, res, r, sess, &ctx)
		if err != nil {
			http.Error(res, "An error ocurred.", http.StatusInternalServerError)
			log.WithError(err).Error("Unable to execute template")
			return
		}

		if template != nil {
			ts := pongo2.NewSet("frontend", pongo2.MustNewLocalFileSystemLoader("templates"))
			tpl, err := ts.FromFile(*template)
			if err != nil {
				log.WithError(err).WithFields(log.Fields{
					"template": *template,
				}).Error("Could not parse template")
				http.Error(res, "An error ocurred.", http.StatusInternalServerError)
				return
			}
			out, err := tpl.Execute(ctx)
			if err != nil {
				log.WithError(err).WithFields(log.Fields{
					"template": *template,
				}).Error("Could not execute template")
				http.Error(res, "An error ocurred.", http.StatusInternalServerError)
				return
			}

			res.Write([]byte(out))
		}
	}
}

func simpleTemplateOutput(template string) httpHelperFunc {
	return func(c context.Context, res http.ResponseWriter, r *http.Request, session *sessions.Session, ctx *pongo2.Context) (*string, error) {
		return &template, nil
	}
}

func stringPointer(s string) *string {
	return &s
}