import os
import sys
import subprocess
import platform
from datetime import datetime
from pathlib import Path
import xml.etree.ElementTree as ET

from config import TITLE, URL, DESCRIPTION, GENERATOR, LANGUAGE, XML_BASE_PATH


class RSSGenerator:
    ATOM_NAMESPACE = "HTTP://WWW.W3.ORG/2005/ATOM"

    def __init__(self):
        self.now = datetime.now().strftime("%a, %d %b %Y %H:%M:%S %z")

        self.output_path = f"../{XML_BASE_PATH}/index.xml" if XML_BASE_PATH else "../index.xml"

        self.post_title = None
        self.post_link = None
        self.post_desc = None
        self.post_date = self.now

        self.tree = None
        self.root = None
        self.channel = None

        self.items = []

    def main(self):
        self.clear()
        if os.path.exists(self.output_path):
            print('RSS feed exists, parsing...')
            self.tree = ET.parse(self.output_path)
            self.parse_existing_feed()
            self.action_screen()

        else:
            print('RSS feed does not exist, generating a new one...')
            Path("/".join(self.output_path.split('/')[:-1])).mkdir(parents=True, exist_ok=True)
            self.generate_new_feed()
            self.request_new_post_details()
            self.push_new_post()
            self.tree = ET.ElementTree(self.root)
            self.action_screen()

    def action_screen(self):
        result = input("\nWhat would you like to do? \n[1] Add a new entry [2] List all posts [3] Delete an entry\n[4] Edit an entry [5] Save [6] Quit Without Saving\nEnter number: ")
        self.clear()
        if int(result) == 1:
            self.request_new_post_details()
            self.push_new_post()
            self.action_screen()

        if int(result) == 2:
            self.list_posts()
            self.action_screen()

        elif int(result) == 3:
            self.delete_post()
            self.action_screen()

        elif int(result) == 4:
            self.edit_post()
            self.action_screen()

        elif int(result) == 5:
            self.tree.write(self.output_path, encoding='utf-8', xml_declaration=True)
            sys.exit(0)

        elif int(result) == 6:
            sys.exit(0)
        else:
            print('Unknown Command!')
            self.action_screen()

    def parse_existing_feed(self):
        self.root = self.tree.getroot()
        self.channel = self.root.find('channel')

    def generate_new_feed(self):

        self.root = ET.Element("rss", {"version": "2.0", "xmlns:atom": self.ATOM_NAMESPACE})

        self.channel = ET.SubElement(self.root, "channel")
        title = ET.SubElement(self.channel, "title")
        title.text = TITLE

        link = ET.SubElement(self.channel, "{http://www.w3.org/2005/Atom}link")
        link.set("rel", "self")
        link.set("href", f"{URL}/{self.output_path}")
        link.set("type", "application/atom+xml")

        desc = ET.SubElement(self.channel, "description")
        desc.text = DESCRIPTION

        generator = ET.SubElement(self.channel, "generator")
        generator.text = GENERATOR

        lang = ET.SubElement(self.channel, "language")
        lang.text = LANGUAGE

    def request_new_post_details(self):
        self.post_title = input("\nPost Title: ")
        self.post_link = input("Post Link: ")
        self.post_desc = input("Post Description: ")

    def push_new_post(self):
        item = ET.SubElement(self.channel, 'item')

        title = ET.SubElement(item, 'title')
        title.text = self.post_title

        link = ET.SubElement(item, 'link')
        link.text = self.post_link

        description = ET.SubElement(item, 'description')
        description.text = self.post_desc

    def list_posts(self):
        print("\nHere is a list of all your posts:")
        for idx, item in enumerate(self.channel.findall('item')):
            title = item.find('title').text

            print(f"[{idx}] {title}")

    def delete_post(self):
        self.list_posts()

        result = input("\nWhich post would you like to delete? Enter number: ")

        for idx, item in enumerate(self.channel.findall('item')):
            if idx == int(result):
                self.channel.remove(item)

    def edit_post(self):
        self.list_posts()

        result = input("\nWhich post would you like to edit? Enter number: ")

        self.request_new_post_details()

        for idx, item in enumerate(self.channel.findall('item')):
            if idx == int(result):
                item.find('title').text = self.post_title
                item.find('description').text = self.post_desc
                item.find('link').text = self.post_link

    def clear(self):
        system = platform.system().lower()
        if system == 'windows':
            subprocess.run('cls', shell=True)
        else:
            subprocess.run('clear', shell=True)


if __name__ == '__main__':
    rss = RSSGenerator()
    rss.main()