package main

import (
        "github.com/mgutz/logxi/v1"
        "golang.org/x/net/html"
        "html/template"
        //"fmt" // пакет для форматированного ввода вывода
        "net/http" // пакет для поддержки HTTP протокола
//      "log"
)
func getChildren(node *html.Node) []*html.Node {
        var children []*html.Node
        for c := node.FirstChild; c != nil; c = c.NextSibling {
                children = append(children, c)
        }
        return children
}

func getAttr(node *html.Node, key string) string {
        for _, attr := range node.Attr {
                if attr.Key == key {
                        return attr.Val
                }
}
        return ""
}

func isText(node *html.Node) bool {
        return node != nil && node.Type == html.TextNode
}

func isElem(node *html.Node, tag string) bool {
        return node != nil && node.Type == html.ElementNode && node.Data == tag
}

func isDiv(node *html.Node, class string) bool {
        return isElem(node, "div") && getAttr(node, "class") == class
}

func readItem(item *html.Node) *Item {
        if a := item.FirstChild; isElem(a, "a") {
                if cs := getChildren(a); len(cs) == 1 && isText(cs[0]){
                        return &Item{
                                Ref:   getAttr(a, "href"),
 Title: cs[0].Data,
                        }
                }
        }
        return nil
}

type Item struct {
        Ref, Time, Title string
}


func downloadNews() []*Item {
        log.Info("sending request to lenta.ru")
        if response, err := http.Get("http://lenta.ru"); err != nil {
                log.Error("request to lenta.ru failed", "error", err)
        } else {
                defer response.Body.Close()
                status := response.StatusCode
                log.Info("got response from lenta.ru", "status", status)
                                           if status == http.StatusOK {
                        if doc, err := html.Parse(response.Body); err != nil {
                                log.Error("invalid HTML from lenta.ru", "error", err)
                        } else {
                                log.Info("HTML from lenta.ru parsed successfully")
                                //items:=search(doc)
                                //log.Info("len(items)", "a:", len(items))
                                /*for i:=0; i<len(items); i++{
                                        log.Info("-- In readItem -->");
                                        log.Info("<a href='a'>", "a:", items[i].Ref)
                                        log.Info("NEWS", "NEWS:", items[i].Title)
                                        log.Info("TIME", "TIME:", items[i].Time)
                                }*/
                                return search(doc)
                        }
                }
 }
        return nil
}

func search(node *html.Node) []*Item {
        if isDiv(node, "b-yellow-box__wrap"){
                var items []*Item
                for c := node.FirstChild; c != nil; c = c.NextSibling {
                        if isDiv(c, "item") {
                                if item := readItem(c); item != nil {
                                        items = append(items, item)
                                }
                        }
                }
                return items
        }
        for c := node.FirstChild; c != nil; c = c.NextSibling {
                if items := search(c); items != nil {
                        return items
                }
        }
        return nil
}

type TemplateItem struct {
        Title string
        Items [] *Item
}

func HomeRouterHandler(w http.ResponseWriter, r *http.Request) {
        r.ParseForm() //анализ аргументов,
        var items []*Item;
        items = downloadNews()
        templItem := TemplateItem{
                Title : "НОВОСТИ",
                Items : items,
        }
        tmpl, _ := template.ParseFiles("templ.html")
        tmpl.Execute(w, templItem)
        //fmt.Fprintf(w, "Hello!") // отправляем данные на клиентскую сторону
}

func main() {
        http.HandleFunc("/", HomeRouterHandler) // установим роутер
        err := http.ListenAndServe(":10060", nil) // задаем слушать порт
        if err != nil {
                log.Fatal("ListenAndServe: ", err)
        }
}