package main

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

	"github.com/golang/glog"

	"code.hackerspace.pl/hscloud/hswaw/site/templates"
)

// parseTemplates parses a set of templates from
// //hswaw/site/templates/$name.html into a Go HTML template. Typical Go text
// templating ordering behaviour applies (this basically replicates
// template.ParseFiles, but for statically embedded files instead).
func parseTemplates(names ...string) (*template.Template, error) {
	if len(names) == 0 {
		return nil, fmt.Errorf("at least one template must be given")
	}

	var t *template.Template
	for _, n := range names {
		path := fmt.Sprintf("hswaw/site/templates/%s.html", n)
		data, ok := templates.Data[path]
		if !ok {
			return nil, fmt.Errorf("template %q (%s) not found", n, path)
		}
		s := string(data)

		if t == nil {
			t = template.New(n)
		}
		_, err := t.Parse(s)
		if err != nil {
			return nil, fmt.Errorf("template %q could not be parsed: %w", n, err)
		}
	}
	return t, nil
}

var (
	tmplAbout   = template.Must(parseTemplates("basic", "about"))
	tmplAboutEn = template.Must(parseTemplates("basic", "about_en"))
	tmplMain    = template.Must(parseTemplates("basic", "main"))
)

// render attempts to render a given Go template with data into the HTTP
// response writer, and logs a warning if anything goes wrong.
func render(w http.ResponseWriter, t *template.Template, data interface{}) {
	if err := t.Execute(w, data); err != nil {
		glog.Warningf("Rendering %v failed: %v", t, err)
	}
}

// handleAbout handles rendering the about page at /about
func (s *service) handleAbout(w http.ResponseWriter, r *http.Request) {
	render(w, tmplAbout, nil)
}

// handleAboutEn handles rendering the about page at /about_en
func (s *service) handleAboutEn(w http.ResponseWriter, r *http.Request) {
	render(w, tmplAboutEn, nil)
}

// handleMain handles rendering the main page at /.
func (s *service) handleMain(w http.ResponseWriter, r *http.Request) {
	render(w, tmplMain, map[string]interface{}{
		"Entries": s.getFeeds(),
	})
}