import sys
import socket
import re
import logging
import pytermgui as ptg
from typing import Tuple

PORT = 1900

logger = logging.getLogger('nex')
logger.setLevel(logging.INFO)
logger.addHandler(logging.FileHandler('nex.log'))


def parse_url(url: str) -> Tuple[str, str]:
    clean_url = url.replace('nex://', '')
    split_url = clean_url.split('/', 1)
    if len(split_url) == 1:
        return clean_url, ''
    return split_url[0], split_url[1]


class Page:
    def __init__(self, url):
        self.url = url
        self.host, self.selector = parse_url(url)
        self.raw_content = ''
        self.content = self.raw_content
        self.links = ['' for i in range(10)]

    def request(self):
        with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as sock:
            try:
                sock.connect((self.host, PORT))
            except ConnectionError as e:
                logger.error(e)
                self.content = f'[error]Could not connect to {self.host}'
                return
            selector = self.selector + '\r\n'
            sock.sendall(selector.encode('ascii'))
            buf = bytearray()
            while True:
                data = sock.recv(4096)
                if len(data) == 0:
                    break
                buf.extend(data)
            try:
                self.raw_content = buf.decode('ascii')
            except UnicodeDecodeError as e:
                logger.error(e)
                self.content = '[warning]Content could not be decoded'
                return
            self.content = self.raw_content
            self._parse_links()
            for i, l in enumerate(self.links):
                self.content = re.sub(l, f'[bold primary]\[{i}][/] {l}',
                                      self.content, 1)

    @property
    def title(self):
        prefix = 'nex://'
        if self.url.startswith(prefix):
            return self.url[len(prefix):]
        return self.url

    def _parse_links(self):
        pattern = re.compile(r'=>\s*([\w/:\.~-]*)\s*')
        self.links = pattern.findall(self.raw_content)


def create_landing_page() -> Page:
    landing_page = Page('about:home')
    landing_page.raw_content = 'Welcome to PyNex'
    landing_page.content = landing_page.raw_content
    return landing_page


class Session:
    def __init__(self):
        home_page = create_landing_page()
        self.pages = {home_page.url: home_page}
        self.history = [home_page.url]
        self.curr_index = 0

    @property
    def current_page(self):
        return self.pages[self.history[self.curr_index]]

    def prev(self):
        if self.curr_index > 0:
            self.curr_index -= 1
        return self.current_page

    def next(self):
        if self.curr_index < len(self.history) - 1:
            self.curr_index += 1
        return self.current_page

    def new_page(self, url):
        self.curr_index += 1
        if self.curr_index >= len(self.history):
            self.history.append(url)
        else:
            self.history[self.curr_index] = url
        page = Page(url)
        page.request()
        self.pages[url] = page
        return self.current_page


class Browser(ptg.WindowManager):
    def __init__(self, session=Session(), *args):
        super().__init__()
        self.layout = ptg.Layout()
        self.session = session

        self.page_container = ptg.Container(self.session.current_page.content)
        self.body = ptg.Window(self.page_container,
                               overflow=ptg.Overflow.SCROLL,
                               vertical_align=ptg.VerticalAlignment.TOP)
        self.footer = ptg.Window(
                ptg.Splitter(
                    ["(B)ack", self.back],
                    ["(F)orward", self.forward],
                    ["(R)eload", self.reload],
                    ["(Q)uit", lambda *_: self.stop()]
                    ),
                box="EMPTY",
                is_persistant=True
                )

        self._create_layout()
        self._create_key_bindings()
        self.update()

    def _create_key_bindings(self):
        self.bind(ptg.keys.DOWN, lambda *_: self.body.scroll(5))
        self.bind(ptg.keys.UP, lambda *_: self.body.scroll(-5))
        self.bind('j', lambda *_: self.body.scroll(5))
        self.bind('k', lambda *_: self.body.scroll(-5))
        self.bind('b', self.back)
        self.bind('f', self.forward)
        self.bind('r', self.reload)
        self.bind('q', lambda *_: self.stop())

        for i in range(10):
            self.bind(f'{i}', lambda widget, key: self.follow_link(key))

    def _create_layout(self):
        self.layout.add_slot("Body")
        self.layout.add_break()
        self.layout.add_slot("Footer", height=1)

        self.add(self.body)
        self.add(self.footer)

    def update(self):
        page = self.session.current_page
        self.page_container.set_widgets([page.content])
        self.body.set_title(f'[bold tertiary]{page.title}', 1)

    def back(self, *args):
        self.session.prev()
        self.update()

    def forward(self, *args):
        self.session.next()
        self.update()

    def reload(self, *args):
        self.session.current_page.request()
        self.update()

    def go(self, url):
        self.session.new_page(url)
        self.update()

    def follow_link(self, key):
        index = int(key)
        url = self.session.current_page.links[index]
        if url.startswith('nex://'):
            self.session.new_page(url)
        else:
            url = '/'.join([self.session.current_page.url.rstrip('/'), url])
            self.session.new_page(url)
        self.update()


def main(url=None):
    with Browser() as browser:
        if url is not None:
            browser.go(url)


if __name__ == '__main__':
    if len(sys.argv) > 1:
        url = sys.argv[1]
    main(url)