package gomailer

import (
	"log"
	"os"
	"path"
	"strings"
	"golang.org/x/net/html"
	"github.com/vanng822/go-premailer/premailer"
)

func Inline(arg string) {
	out := LoadTemplate(arg, true)

	dir := path.Dir(arg)
	ext := path.Ext(arg)
	base := strings.ReplaceAll(path.Base(arg), ext, "")
	output_file := path.Join(dir, base+"_inlined"+ext)
	log.Printf("Template: %s -> %s", arg, output_file)

	f, err := os.Create(output_file)
	if err != nil {
		log.Fatal("error inlining html: " + err.Error())
	}
	_, err = f.WriteString(out)

	if err != nil {
		log.Fatal("error inlining html: " + err.Error())
	}
}

func LoadTemplate(template string, inline bool) (string) {
	rawhtml, err := os.ReadFile(template)
	if err != nil {
			log.Fatal("error loading template: " + err.Error())
	}

	if inline {
		prem, err := premailer.NewPremailerFromBytes(rawhtml, premailer.NewOptions())
		if err != nil {
			log.Fatal("error inlining html: " + err.Error())
		}

		inlinehtml, err := prem.Transform()
		if err != nil {
			log.Fatal("error transforming html: " + err.Error())
		}
		return inlinehtml
	}

	return string(rawhtml)
}

func FindSrcInHtml(doc string) []string {
	var results []string
	reader := strings.NewReader(doc)
	if document, err := html.Parse(reader); err == nil {

		var parser func(*html.Node)
		parser = func(n *html.Node) {
			if n.Type == html.ElementNode && n.Data == "img" {

				var imgSrcUrl string

				for _, element := range n.Attr {
					if element.Key == "src" {
						imgSrcUrl = element.Val
						log.Print("found image:" + imgSrcUrl)
						results = append(results, imgSrcUrl)
					}
				}
			}

			for c := n.FirstChild; c != nil; c = c.NextSibling {
				parser(c)
			}

		}
		parser(document)
	} else {
		log.Fatalln("Parse html error", err)
	}
	return results
}