import os
import sys
import subprocess
import platform
from uuid import uuid4
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, EXECUTE_FROM_RSS_GENERATOR_DIR


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"

        if not EXECUTE_FROM_RSS_GENERATOR_DIR:
            self.output_path = self.output_path.replace('../', '')

        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}".replace('../', ''))
        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

        guid = ET.SubElement(item, 'guid')
        guid.text = str(uuid4())

        pub_date = ET.SubElement(item, 'pubDate')
        pub_date.text = self.now

    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()