package main

import (
	"golang.org/x/net/html"
	"net/url"
	"strconv"
	"strings"
)

func ValidateHtml(config Config, n *html.Node, depth int, imgcount *int) (bool, string) {
	if depth > config.MaxHtmlDepth {
		return false, "HTML document nests elements too deeply.  " + strconv.Itoa(config.MaxHtmlDepth) + " levels is the limit."
	}
	if n.Type == html.ElementNode {
		_, ok := config.BadTagsMap[n.Data]
		if ok {
			return false, "HTML document contains forbiden tag: " + n.Data
		}
		if n.Data == "img" {
			*imgcount += 1
		}
		if *imgcount > config.MaxImages {
			return false, "HTML document contains more than " + strconv.Itoa(config.MaxImages) + " images."
		}
		for _, a := range n.Attr {
			_, ok := config.BadAttrsMap[a.Key]
			if ok {
			return false, "HTML document contains <" + n.Data + "> tag with forbiden attribute: " + a.Key
			}
			if a.Key == "src" && strings.Contains(a.Val, "://") {
				return false, "HTML document includes <" + n.Data + "> tag with a remote src"
			}
			if n.Data == "a" && a.Key == "href" {
				u, err := url.Parse(a.Val)
				if err != nil {
					continue
				}
				for _, bad_dom := range config.BadDomains {
					if u.Host == bad_dom || strings.HasSuffix(u.Host, bad_dom) {
						return false, "HTML document contains link to forbidden host: " + u.Host
					}
				}
			}
		}
	}
	for c := n.FirstChild; c != nil; c = c.NextSibling {
		err, msg := ValidateHtml(config, c, depth+1, imgcount)
		if err == false {
			return err, msg
		}
	}
	return true, ""

}