package page

import (
	"bytes"
	"errors"
	"io/fs"
	"net/http"
)

// Render5xx is automatically called if any render fails,
// additionally you can call it for your own uses. It will
// try to use the 5xx template but will fall back to a plain
// page if that fails.
func Render5xx(w http.ResponseWriter, r *http.Request,
	vars map[string]interface{}, statusCode int) {
	p := NewPage(TemplateDirectory + "/5xx")

	buf := &bytes.Buffer{}

	err := p.Render(buf)
	if err != nil {
		logErr(r, "while trying 5xx", err)
		http.Error(w, "Internal server error", statusCode)

		return
	}

	w.WriteHeader(statusCode)

	_, _ = w.Write(buf.Bytes())

	logReq(r, statusCode)
}

// Render4xx is mostly used to render a 404 page, pulls from 404 template.
// automatically called by Render if a page is missing.
func Render4xx(w http.ResponseWriter, r *http.Request,
	vars map[string]interface{}, statusCode int) {
	p := NewPage(TemplateDirectory + "/4xx")

	buf := &bytes.Buffer{}

	err := p.Render(buf)
	if err != nil {
		logErr(r, "while trying 404", err)
		Render5xx(w, r, vars, http.StatusInternalServerError)

		return
	}

	w.WriteHeader(statusCode)

	_, err = w.Write(buf.Bytes())
	if err != nil {
		Render5xx(w, r, nil, http.StatusInternalServerError)

		return
	}

	logReq(r, statusCode)
}

// Render is a lower level option, allowing you to specify local
// variables and the status code in which to return.
func Render(w http.ResponseWriter, r *http.Request,
	path string, vars map[string]interface{}, statusCode int) {
	// Sepcifically use the specified path for the page
	p := NewPage(path)

	if vars != nil {
		p.Vars = vars
	}

	buf := &bytes.Buffer{}

	err := p.Render(buf)
	if err != nil {
		if errors.Is(err, fs.ErrNotExist) {
			Render4xx(w, r, vars, http.StatusNotFound)

			return
		}

		logErr(r, "rendering encountered", err)
		Render5xx(w, r, vars, http.StatusInternalServerError)

		return
	}

	w.WriteHeader(statusCode)

	_, err = w.Write(buf.Bytes())
	if err != nil {
		logErr(r, "while writing to buf", err)
		Render5xx(w, r, nil, http.StatusInternalServerError)

		return
	}

	logReq(r, statusCode)
}

// RenderWithVars allows you to specify a specific page and whether or not
// you wish to override vars. If left nil they will not be overridden.
// Also see RenderForPath if you don't need to override them.
func RenderWithVars(w http.ResponseWriter, r *http.Request,
	path string, vars map[string]interface{}) {
	Render(w, r, path, vars, http.StatusOK)
}

// RenderForPath takes the path to a page and finish up the rendering
// Allowing you to place logic on what page is rendered by your handlers.
func RenderForPath(w http.ResponseWriter, r *http.Request, path string) {
	RenderWithVars(w, r, path, nil)
}