package main

import (
	"fmt"
	"net/http"
	"os"
	"strings"

	"encoding/csv"

  "time"
	"golang.org/x/net/html"
)

type Book struct {
	Title     string
	Price     string
	Available bool
}

func FindFirstElement(root *html.Node, name string) *html.Node {
	if root.Type == html.ElementNode && root.Data == name {
		return root
	}
	for c := root.FirstChild; c != nil; c = c.NextSibling {
		el := FindFirstElement(c, name)
		if el != nil {
			return el
		}
	}
	return nil
}

func Scrape(url string) {
	res, err := http.Get(url)
	if err != nil {
		LogList.Log(err.Error())
		return
	}
	defer res.Body.Close()

	root, err := html.Parse(res.Body)
	if err != nil {
		LogList.Log(err.Error())
		return
	}

	ol := FindFirstElement(root, "ol")

	books := []Book{}

	for c := ol.FirstChild; c != nil; c = c.NextSibling {
		if c.Type == html.ElementNode && c.Data == "li" {
			article := FindFirstElement(c, "article")
			article.RemoveChild(FindFirstElement(article, "div"))
			h3 := FindFirstElement(article, "h3")
			title := h3.FirstChild.Attr[1].Val
			productPrice := FindFirstElement(article, "div")
			price := productPrice.FirstChild.NextSibling.FirstChild.Data
			isAvailable := productPrice.FirstChild.NextSibling.NextSibling.NextSibling.FirstChild.NextSibling.NextSibling.Data
			isAvailable = strings.ReplaceAll(isAvailable, "\n", "")
			isAvailable = strings.ReplaceAll(isAvailable, " ", "")

			if len(title) > 0 && len(price) > 0 && len(isAvailable) > 0 {
				books = append(books, Book{Title: title, Price: price, Available: isAvailable == "Instock"})
			} else {
				LogList.Log(fmt.Sprintf("Error: %s %s %s", title, price, isAvailable))
				return
			}
		}
	}

	file, err := os.Create("books.csv")
	if err != nil {
		LogList.Log(err.Error())
		return
	}
	defer file.Close()

	writer := csv.NewWriter(file)
	defer writer.Flush()

	err = writer.Write([]string{"Title", "Price", "Available"})
	if err != nil {
		LogList.Log(err.Error())
		return
	}

	for _, book := range books {
		err = writer.Write([]string{book.Title, book.Price, fmt.Sprintf("%t", book.Available)})
		if err != nil {
			LogList.Log(err.Error())
			return
		}
	}

}

func main() {
	url := "https://books.toscrape.com/catalogue/category/books/travel_2/index.html"
  Scrape(url)
  LogList.Log("Done!")
  f, err := os.Create("logs.txt")
  if err != nil {
    fmt.Println(err)
  }
  defer f.Close()
  _, err = f.Write([]byte(time.Now().String() + ":" + url + "\n" +  LogList.ToString()))
  if err != nil {
    fmt.Println(err)
  }
}