package page

import (
	"os"
	"io/fs"
	"errors"
	"path/filepath"
	"net/http"
	"sanine.net/git/phlox/config"
)


type Pages struct {
	Login string
	LoggedIn string
	Error404 string
	Error500 string
}


func (p Pages) ServeLogin(w http.ResponseWriter) {
	w.Write([]byte(p.Login))
}


func (p Pages) ServeLoggedIn(w http.ResponseWriter) {
	w.Write([]byte(p.LoggedIn))
}


func (p Pages) ServeError404(w http.ResponseWriter) {
	w.WriteHeader(http.StatusNotFound)
	w.Write([]byte(p.Error404))
}


func (p Pages) ServeError500(w http.ResponseWriter) {
	w.WriteHeader(http.StatusInternalServerError)
	w.Write([]byte(p.Error500))
}


type DefaultPage func() (string, error)


func fileExists(filename string) (bool, error) {
	_, err := os.Stat(filename)
	if err == nil {
		return true, nil
	} else if errors.Is(err, fs.ErrNotExist) {
		return false, nil
	} else {
		// unknown error
		return false, err
	}
}


func loadPage(c config.Config, filename string, fallback DefaultPage) (string, error) {
	fullPath := filepath.Join(c.AssetDirectory, filename)
	exist, err := fileExists(fullPath)
	if err != nil {
		return "", err
	}

	if exist {
		bytes, err := os.ReadFile(fullPath)
		if err != nil {
			return "", err
		}
		return string(bytes), nil
	} else {
		// file does not exist
		// use built-in
		str, err := fallback()
		if err != nil {
			return "", err
		}
		return str, nil
	}
}


func LoadPages(c config.Config) (Pages, error) {
	var pages Pages
	var err error

	pages.Login, err = loadPage(c, "login.html", DefaultLogin)
	if err != nil {
		return Pages{}, err
	}

	pages.LoggedIn, err = loadPage(c, "logged_in.html", DefaultLoggedIn)
	if err != nil {
		return Pages{}, err
	}


	pages.Error404, err = loadPage(c, "404.html", DefaultError404)
	if err != nil {
		return Pages{}, err
	}

	pages.Error500, err = loadPage(c, "500.html", DefaultError500)
	if err != nil {
		return Pages{}, err
	}

	return pages, nil
}