package view

import (
	"embed"
	"html/template"
	"net/http"
	"strings"
	"reflect"

	"xengineering.eu/ceres/model"

	"github.com/gorilla/mux"
)

//go:embed html/*.html
var htmlFS embed.FS

var html *template.Template

func Init() {
	html = template.Must(template.New("html").ParseFS(htmlFS, "html/*.html"))
}

func HandlerHTML(prototype model.ReadableData) http.HandlerFunc {
	t := reflect.TypeOf(prototype).Elem()

	tmpl := t.String()
	tmpl = strings.TrimPrefix(tmpl, `model.`)
	tmpl = strings.ToLower(tmpl)

	return func(w http.ResponseWriter, r *http.Request) {
		data := reflect.New(t).Interface().(model.ReadableData)
		var err error

		v := reflect.ValueOf(data).Elem()
		if v.Kind() == reflect.Struct {
			id, ok := mux.Vars(r)[`id`]
			if ok {
				f := v.FieldByName(`Id`)
				if f.IsValid() && f.CanSet() && f.Kind() == reflect.String {
					f.SetString(id)
				} else {
					http.Error(w, `Requested struct data does not have a settable string ID`, http.StatusBadRequest)
					return
				}
			} else {
				http.Error(w, `Requested struct data without giving an ID`, http.StatusBadRequest)
				return
			}
		}

		err = data.FromDB()
		if err != nil {
			http.Error(w, err.Error(), http.StatusInternalServerError)
			return
		}

		err = html.ExecuteTemplate(w, tmpl, data)
		if err != nil {
			http.Error(w, err.Error(), http.StatusInternalServerError)
			return
		}
	}
}