package main

import (
	"golang.org/x/net/html"
	"net/http"
	"log"
	"html/template"
)

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

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 isSection(node *html.Node, class string) bool {
	return isElem(node, "section") && getAttr(node, "class") == class
}

type Item struct {
	Ref, Time, Title string
}

func downloadNews(w http.ResponseWriter) []Item {
	println("sending request to lenta.ru")
	if response, err := http.Get("http://lenta.ru"); err != nil {
		println("request to lenta.ru failed", "error", err)
	} else {
		defer response.Body.Close()
		status := response.StatusCode
		println("got response from lenta.ru", "status", status)
		if status == http.StatusOK {
			if doc, err := html.Parse(response.Body); err != nil {
				println("invalid HTML from lenta.ru", "error", err)
			} else {
				println("HTML from lenta.ru parsed successfully")
				t, _ := template.ParseFiles("go.html")
				var Items []Item
				Items = search(w, doc, Items)
				//println(len(Items))
				data := struct {
					Items []Item //создаю айтемы
				}{
					Items: Items, //кладу в data айтемы
				}
				t.Execute(w, data) //в html файл отправляет data
				return Items
			}
		}
	}
	return nil
}

func search(w http.ResponseWriter, node *html.Node, items []Item) []Item {
	if isSection(node, "b-layout js-layout b-layout_main") {
		for one := node.FirstChild; one != nil; one = one.NextSibling { // g-layout
			for two := one.FirstChild; two != nil; two = two.NextSibling { //row
				for three := two.FirstChild; three != nil; three = three.NextSibling { //span8 js-main__content OR span4 b-sidebar-stickycolumn js-main__sidebars
					for four := three.FirstChild; four != nil; four = four.NextSibling { //row b-top7-for-main js-top-seven OR b-sidebar-stickycolumn__top js-main__sidebar-top

						for five := four.FirstChild; five != nil; five = five.NextSibling { //span4

							if isDiv(five, "span4") {
								for item_firstItem := five.FirstChild; item_firstItem != nil; item_firstItem = item_firstItem.NextSibling {
									if isDiv(item_firstItem, "item") || isDiv(item_firstItem, "first-item") {
										if resItem := readItem(item_firstItem); resItem.Time != "nil" {
											items = append(items, resItem)
											println("")
											println(resItem.Time)
											println(resItem.Title)
											println(resItem.Ref)
										}
									}
								}
							}

							for six := five.FirstChild; six != nil; six = six.NextSibling { // b-yellow-box__wrap
								if getAttr(six, "class") == "b-yellow-box__wrap" {
									for item_firstItem := six.FirstChild; item_firstItem != nil; item_firstItem = item_firstItem.NextSibling {
										if isDiv(item_firstItem, "item") || isDiv(item_firstItem, "first-item") {
											if resItem := readItem(item_firstItem); resItem.Time != "nil" {
												items = append(items, resItem)
												println("")
												println(resItem.Time)
												println(resItem.Title)
												println(resItem.Ref)
											}
										}
									}
								}
							}

						}
					}
				}
			}
		}
	}
	for recurs := node.FirstChild; recurs != nil; recurs = recurs.NextSibling {
		if items := search(w, recurs, items); items != nil {
			return items
		}
	}
	return items
}

func readItem(item *html.Node) Item {
	var myItem Item
	for itemChild := item.FirstChild; itemChild != nil; itemChild = itemChild.NextSibling {
		if isElem(itemChild, "a") {
			myItem.Ref = "Ref: " + getAttr(itemChild, "href")
			for itemChildChild := itemChild.FirstChild; itemChildChild != nil; itemChildChild = itemChildChild.NextSibling {
				if len(getAttr(itemChildChild, "datetime")) != 0 {
					myItem.Time = "Time: " + getAttr(itemChildChild, "datetime")
				}
				title := itemChildChild.Data
				if len(title) >= 6 {
					myItem.Title = "Title: " + title
					if len(myItem.Time) == 0 {
						myItem.Time = "Main News"
					}
					return myItem
				}
			}
		}
	}
	myItem.Time = "nil"
	return myItem
}

func HomeRouterHandler(w http.ResponseWriter, r *http.Request) {
	downloadNews(w)
}

func main() {
	http.HandleFunc("/", HomeRouterHandler)   // установим роутер
	err := http.ListenAndServe(":12675", nil) // задаем слушать порт
	if err != nil {
		log.Fatal("ListenAndServe: ", err)
	}
}