#!/usr/bin/env python3

#TODO: make sure things dont explode no matter what terminal size
# -> prevent linebreaks in a single story
# -> only load as many stories as fit

import requests
from bs4 import BeautifulSoup as Soup
import curses
import webbrowser

from dataclasses import dataclass

spinner_states = ['-', '\\', '|', '/']

@dataclass
class Story:
    id: int
    title: str
    link: str
    author: str
    votes: int
    comments: int

def get_topstories():
    # Query Hacker News API for top stories and their titles/links
    # returns the top 500 stories, so quite enough.
    url = 'https://hacker-news.firebaseio.com/v0/topstories.json'
    r = requests.get(url)
    if not r.ok:
        raise Exception('Error fetching data from Hacker News API')
    return r.json()

def get_story(story_id):
    story_url = f'https://hacker-news.firebaseio.com/v0/item/{story_id}.json'
    s = requests.get(story_url).json()
    return Story(s['id'],
                 s['title'],
                 s['url'] if 'url' in s else 'No URL',
                 s['by'],
                 s['score'],
                 len(s['kids']) if 'kids' in s else 0)


def footer(stdscr, content):
    stdscr.addstr(curses.LINES-1, 0, content, curses.A_REVERSE)


def main(stdscr):
    stdscr.clear()

    _, width = stdscr.getmaxyx();

    num_stories = curses.LINES - 3 # headline, detail, footer
    topstories = get_topstories()
    stories = []
    for idx, i in enumerate(topstories[:num_stories]):
        stdscr.clear()
        footer(stdscr, f'[{spinner_states[idx%4]}] Getting stories...')
        stdscr.refresh()
        stories.append(get_story(i))

    # Display list of stories in terminal window with arrow key navigation
    current_pos = 0
    while True:
        stdscr.clear()
        stdscr.addstr('Hacker News Top Stories:\n')
        for i, story in enumerate(stories):
            prefix = '>>> ' if i == current_pos else '   '
            # calculate length of line
            text = f'{prefix} ()\n'
            chars_available = width - len(text)
            max_title_len = min((chars_available//3)*2, len(story.title))
            max_url_len = chars_available - max_title_len

            title = story.title[:max_title_len-1] + "…" if len(story.title) > max_title_len else story.title
            link = story.link.replace('https://', '').replace('http://', '')
            link = link[:max_url_len-1] + "…" if len(link) > max_url_len else link

            text = '{}{} ({})\n'.format(prefix, title, link.replace('https://', '').replace('http://', ''))
            stdscr.addstr(text)
            if i == current_pos:
                detail = f'    by {story.author} | {story.comments} comments | {story.votes} points\n'
                stdscr.addstr(detail)
        footer(stdscr, f'Loaded {num_stories} stories.')

        stdscr.refresh()
        c = stdscr.getch()
        if c == ord('q'):  # Quit
            break
        elif c == curses.KEY_UP:
            current_pos -= 1
            if current_pos < 0:
                current_pos = len(stories)-1
        elif c == curses.KEY_DOWN:
            current_pos += 1
            if current_pos >= len(stories):
                current_pos = 0
        elif c == ord('c'):
            webbrowser.open(f'https://news.ycombinator.com/item?id={stories[current_pos].id}')
        elif c == curses.KEY_ENTER or c == 10:
            webbrowser.open(stories[current_pos].link)

curses.wrapper(main)