package main

import (
	"context"
	"fmt"
	"html/template"
	"net/http"
	"time"

	"github.com/Xe/ln"
	analytics "gopkg.in/segmentio/analytics-go.v3"
)

func logTemplateTime(name string, from time.Time) {
	now := time.Now()
	ln.Log(context.Background(), ln.F{"action": "template_rendered", "dur": now.Sub(from).String(), "name": name})
}

func (s *Site) renderTemplatePage(templateFname string, data interface{}) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		defer logTemplateTime(templateFname, time.Now())

		getTranslation := func(group, key string, vals ...interface{}) string {
			var lc locale
			var ok bool
			locale, err := GetPreferredLocale(r)
			if err != nil {
				ln.Error(r.Context(), err)
				lc = s.t.locales["en"]
				goto overwith
			}

			lc, ok = s.t.Get(locale.Lang)
			if !ok {
				ln.Log(r.Context(), ln.F{"msg": "unknown language requested", "lang": locale.Lang, "header": r.Header.Get("Accept-Language")})
				lc = s.t.locales["en"]
				goto overwith
			}

		overwith:
			return lc.Value(group, key, vals...)
		}
		funcMap := template.FuncMap{
			"trans": getTranslation,
		}

		var t *template.Template = template.New(templateFname).Funcs(funcMap)
		var err error

		t, err = t.ParseFiles("templates/base.html", "templates/"+templateFname)
		if err != nil {
			w.WriteHeader(http.StatusInternalServerError)
			ln.Error(context.Background(), err, ln.F{"action": "renderTemplatePage", "page": templateFname})
			fmt.Fprintf(w, "error: %v", err)
		}

		err = t.Execute(w, data)
		if err != nil {
			panic(err)
		}
	})
}

func (s *Site) showPost(w http.ResponseWriter, r *http.Request) {
	if r.RequestURI == "/blog/" {
		http.Redirect(w, r, "/blog", http.StatusSeeOther)
		return
	}

	var p *Post
	for _, pst := range s.Posts {
		if pst.Link == r.RequestURI[1:] {
			p = pst
		}
	}

	if p == nil {
		w.WriteHeader(http.StatusNotFound)
		s.renderTemplatePage("error.html", "no such post found: "+r.RequestURI).ServeHTTP(w, r)
		return
	}

	s.renderTemplatePage("blogpost.html", p).ServeHTTP(w, r)

	if s.segment != nil {
		err := s.segment.Enqueue(analytics.Track{
			UserId:     Hash("h", r.Header.Get("X-Forwarded-For")),
			Event:      "Post Viewed",
			Properties: analytics.NewProperties().SetURL(r.RequestURI).SetTitle(p.Title),
		})
		if err != nil {
			ln.Error(r.Context(), err)
		}
	}
}