package main

import (
	"fmt"
	"golang.org/x/net/html"
	"html/template"
	"io/ioutil"
	"os"
	"path/filepath"
	"strings"
	"time"
)

//Post : Is exported
type Post struct {
	Date     time.Time
	Title    string
	URLTitle string
	Content  template.HTML
}

const layout = "2006-01-02"

var modTime time.Time
var postsCollection []Post

func postHandlerRoutine(duration time.Duration) {
	for {
		if isFolderModified() == true {
			postsCollection = nil
			filepath.Walk("./posts/", newPost)
			for _, post := range postsCollection {
				sortPostAccordingToDate(post, postsCollection)
			}
		}
		time.Sleep(duration * time.Second)
	}
}

func isFolderModified() bool {
	f, _ := os.Open("./dir")
	info, _ := f.Stat()
	_modTime := info.ModTime()
	if modTime != _modTime {
		modTime = _modTime
		return true
	}
	return false
}

func newPost(path string, f os.FileInfo, err error) error {
	postsCollection = append(postsCollection, getPost(path))
	return nil
}

func getPost(title string) Post {
	content, err := ioutil.ReadFile(title)
	if err != nil {
		fmt.Println(content)
		return Post{}
	}

	s := string(content)
	doc, _ := html.Parse(strings.NewReader(s))

	var p = Post{
		getDate(doc),
		title,
		spaceToHyphen(title),
		template.HTML(string(content[:len(content)])),
	}

	return p
}

func getDate(n *html.Node) time.Time {
	var t time.Time
	if n.Type == html.ElementNode && n.Data == "time" {
		for _, a := range n.Attr {
			if a.Key == "datetime" {
				t, _ = time.Parse(layout, a.Val)
			}
		}
	}
	for c := n.FirstChild; c != nil; c = c.NextSibling {
		t = getDate(c)
	}
	return t
}

func spaceToHyphen(s string) string {
	return strings.Replace(s, " ", "-", -1)
}

func getNewestPosts(numberOfPosts int) []Post {
	var posts []Post
	for i := numberOfPosts; i > 0; i-- {
		post := postsCollection[i]
		posts = append(posts, getPostByURLTitle(post.URLTitle))
	}
	return posts
}

func getPostByURLTitle(title string) Post {
	for _, post := range postsCollection {
		if post.URLTitle == title {
			return post
		}
	}
	return Post{}
}

func sortPostAccordingToDate(post Post, arr []Post) {
	for i, p := range arr {
		if p.Date.After(post.Date) {
			s := make([]Post, len(arr)+1, cap(arr)+1)
			copy(s[:], arr[:])     //make a copy of the slice
			copy(s[i+1:], arr[i:]) //move the upper part of the slice ahead, creating a hole
			s[i] = post            //insert new element into hole
		}
	}
	postsCollection = append(postsCollection, post)
}