import curses
import sys

from requests.exceptions import HTTPError

from .errors import SubredditNameError
from .page import BasePage
from .submission import SubmissionPage
from .content import SubredditContent
from .utils import (LoadScreen, Symbol, Color, text_input, display_message,
                    display_help, open_browser)

# Used to keep track of browsing history across the current session
_opened_links = set()

class SubredditPage(BasePage):

    def __init__(self, stdscr, reddit, name):

        self.loader = LoadScreen(stdscr)

        content = SubredditContent.from_name(reddit, name, self.loader)
        super(SubredditPage, self).__init__(stdscr, reddit, content)

    def loop(self):

        self.draw()

        while True:
            cmd = self.stdscr.getch()

            if cmd in (curses.KEY_UP, ord('k')):
                self.move_cursor_up()
                self.clear_input_queue()

            elif cmd in (curses.KEY_DOWN, ord('j')):
                self.move_cursor_down()
                self.clear_input_queue()

            elif cmd in (curses.KEY_RIGHT, curses.KEY_ENTER, ord('l')):
                self.open_submission()
                self.draw()

            elif cmd == ord('o'):
                self.open_link()
                self.draw()

            elif cmd in (curses.KEY_F5, ord('r')):
                self.refresh_content()
                self.draw()

            elif cmd == ord('?'):
                display_help(self.stdscr)
                self.draw()

            elif cmd == ord('a'):
                self.upvote()
                self.draw()

            elif cmd == ord('z'):
                self.downvote()
                self.draw()

            elif cmd == ord('q'):
                sys.exit()

            elif cmd == curses.KEY_RESIZE:
                self.draw()

            elif cmd == ord('/'):
                self.prompt_subreddit()
                self.draw()

    def refresh_content(self, name=None):

        name = name or self.content.name

        try:
            self.content = SubredditContent.from_name(
                self.reddit, name, self.loader)

        except SubredditNameError:
            display_message(self.stdscr, ['Invalid subreddit'])

        except HTTPError:
            display_message(self.stdscr, ['Could not reach subreddit'])

        else:
            self.nav.page_index, self.nav.cursor_index = 0, 0
            self.nav.inverted = False

    def prompt_subreddit(self):
        "Open a prompt to type in a new subreddit"

        attr = curses.A_BOLD | Color.CYAN
        prompt = 'Enter Subreddit: /r/'
        n_rows, n_cols = self.stdscr.getmaxyx()
        self.stdscr.addstr(n_rows-1, 0, prompt, attr)
        self.stdscr.refresh()
        window = self.stdscr.derwin(1, n_cols-len(prompt),n_rows-1, len(prompt))
        window.attrset(attr)

        out = text_input(window)
        if out is not None:
            self.refresh_content(name=out)

    def open_submission(self):
        "Select the current submission to view posts"

        data = self.content.get(self.nav.absolute_index)
        page = SubmissionPage(self.stdscr, self.reddit, submission=data['object'])
        page.loop()

        if data['url'] == 'selfpost':
            global _opened_links
            _opened_links.add(data['url_full'])

    def open_link(self):
        "Open a link with the webbrowser"

        url = self.content.get(self.nav.absolute_index)['url_full']
        open_browser(url)

        global _opened_links
        _opened_links.add(url)

    @staticmethod
    def draw_item(win, data, inverted=False):

        n_rows, n_cols = win.getmaxyx()
        n_cols -= 1  # Leave space for the cursor in the first column

        # Handle the case where the window is not large enough to fit the data.
        valid_rows = range(0, n_rows)
        offset = 0 if not inverted else -(data['n_rows'] - n_rows)

        n_title = len(data['split_title'])
        for row, text in enumerate(data['split_title'], start=offset):
            if row in valid_rows:
                text = Symbol.clean(text)
                win.addnstr(row, 1, text, n_cols-1, curses.A_BOLD)

        row = n_title + offset
        if row in valid_rows:
            seen = (data['url_full'] in _opened_links)
            link_color = Color.MAGENTA if seen else Color.BLUE
            attr = curses.A_UNDERLINE | link_color
            text = Symbol.clean('{url}'.format(**data))
            win.addnstr(row, 1, text, n_cols-1, attr)

        row = n_title + offset + 1
        if row in valid_rows:
            text = Symbol.clean('{score} '.format(**data))
            win.addnstr(row, 1, text, n_cols-1)

            if data['likes'] is None:
                text, attr = Symbol.BULLET, curses.A_BOLD
            elif data['likes']:
                text, attr = Symbol.UARROW, curses.A_BOLD | Color.GREEN
            else:
                text, attr = Symbol.DARROW, curses.A_BOLD | Color.RED
            win.addnstr(text, n_cols-win.getyx()[1], attr)

            text = Symbol.clean(' {created} {comments}'.format(**data))
            win.addnstr(text, n_cols-win.getyx()[1])

        row = n_title + offset + 2
        if row in valid_rows:
            text = Symbol.clean('{author}'.format(**data))
            win.addnstr(row, 1, text, n_cols-1, curses.A_BOLD)
            text = Symbol.clean(' {subreddit}'.format(**data))
            win.addnstr(text, n_cols-win.getyx()[1], Color.YELLOW)
            text = Symbol.clean(' {flair}'.format(**data))
            win.addnstr(text, n_cols-win.getyx()[1], Color.RED)