package api

import (
	"bytes"
	"errors"
	"html/template"
	"log"
	"net/http"
	"os"
)

func renderTemplate(context *RequestContext, templateName string, showBaseHtml bool, data interface{}) (bytes.Buffer, error) {
	templatePath := context.Args.TemplatePath
	basePath := templatePath + "/base_empty.html"
	if showBaseHtml {
		basePath = templatePath + "/base.html"
	}

	templateLocation := templatePath + "/" + templateName
	tmpl, err := template.New("").ParseFiles(templateLocation, basePath)
	if err != nil {
		return bytes.Buffer{}, err
	}

	if data == nil {
		data = map[string]interface{}{}
	}
	if context.User != nil {
		data.(map[string]interface{})["User"] = context.User
	}

	var buffer bytes.Buffer
	err = tmpl.ExecuteTemplate(&buffer, "base", data)

	if err != nil {
		return bytes.Buffer{}, err
	}
	return buffer, nil
}

func TemplateContinuation(path string, data interface{}, showBase bool) Continuation {
	return func(context *RequestContext, req *http.Request, resp http.ResponseWriter) ContinuationChain {
		return func(success Continuation, failure Continuation) ContinuationChain {
			html, err := renderTemplate(context, path, true, data)
			if errors.Is(err, os.ErrNotExist) {
				resp.WriteHeader(404)
				html, err = renderTemplate(context, "404.html", true, nil)
				if err != nil {
					log.Println("error rendering 404 template", err)
					resp.WriteHeader(500)
					return failure(context, req, resp)
				}

				resp.Header().Set("Content-Type", "text/html")
				resp.Write(html.Bytes())
				return failure(context, req, resp)
			}

			if err != nil {
				log.Println("error rendering template", err)
				resp.WriteHeader(500)
				resp.Write([]byte("error rendering template"))
				return failure(context, req, resp)
			}

			resp.WriteHeader(200)
			resp.Header().Set("Content-Type", "text/html")
			resp.Write(html.Bytes())
			return success(context, req, resp)
		}
	}
}