import argparse
import base64
import io
import json
import os
import pickle
import urllib.parse as urlparse
import uuid
from datetime import datetime, timedelta
from functools import wraps

import waitress
from app import app
from app.models.config import Config
from app.models.endpoint import Endpoint
from app.request import Request, TorError
from app.utils.bangs import resolve_bang
from app.filter import Filter
from app.utils.misc import read_config_bool, get_client_ip, get_request_url, \
    check_for_update
from app.utils.results import add_ip_card, bold_search_terms,\
    add_currency_card, check_currency, get_tabs_content
from app.utils.search import Search, needs_https, has_captcha
from app.utils.session import generate_user_key, valid_user_session
from bs4 import BeautifulSoup as bsoup
from flask import jsonify, make_response, request, redirect, render_template, \
    send_file, session, url_for, g
from requests import exceptions, get
from requests.models import PreparedRequest
from cryptography.fernet import Fernet, InvalidToken
from cryptography.exceptions import InvalidSignature

# Load DDG bang json files only on init
bang_json = json.load(open(app.config['BANG_FILE'])) or {}

ac_var = 'WHOOGLE_AUTOCOMPLETE'
autocomplete_enabled = os.getenv(ac_var, '1')


def auth_required(f):
    @wraps(f)
    def decorated(*args, **kwargs):
        auth = request.authorization

        # Skip if username/password not set
        whoogle_user = os.getenv('WHOOGLE_USER', '')
        whoogle_pass = os.getenv('WHOOGLE_PASS', '')
        if (not whoogle_user or not whoogle_pass) or (
                auth
                and whoogle_user == auth.username
                and whoogle_pass == auth.password):
            return f(*args, **kwargs)
        else:
            return make_response('Not logged in', 401, {
                'WWW-Authenticate': 'Basic realm="Login Required"'})

    return decorated


def session_required(f):
    @wraps(f)
    def decorated(*args, **kwargs):
        if (valid_user_session(session) and
                'cookies_disabled' not in request.args):
            g.session_key = session['key']
        else:
            session.pop('_permanent', None)
            g.session_key = app.default_key

        # Clear out old sessions
        invalid_sessions = []
        for user_session in os.listdir(app.config['SESSION_FILE_DIR']):
            file_path = os.path.join(
                app.config['SESSION_FILE_DIR'],
                user_session)

            try:
                # Ignore files that are larger than the max session file size
                if os.path.getsize(file_path) > app.config['MAX_SESSION_SIZE']:
                    continue

                with open(file_path, 'rb') as session_file:
                    _ = pickle.load(session_file)
                    data = pickle.load(session_file)
                    if isinstance(data, dict) and 'valid' in data:
                        continue
                    invalid_sessions.append(file_path)
            except Exception:
                # Broad exception handling here due to how instances installed
                # with pip seem to have issues storing unrelated files in the
                # same directory as sessions
                pass

        for invalid_session in invalid_sessions:
            try:
                os.remove(invalid_session)
            except FileNotFoundError:
                # Don't throw error if the invalid session has been removed
                pass

        return f(*args, **kwargs)

    return decorated


@app.before_request
def before_request_func():
    global bang_json

    # Check for latest version if needed
    now = datetime.now()
    if now - timedelta(hours=24) > app.config['LAST_UPDATE_CHECK']:
        app.config['LAST_UPDATE_CHECK'] = now
        app.config['HAS_UPDATE'] = check_for_update(
            app.config['RELEASES_URL'],
            app.config['VERSION_NUMBER'])

    g.request_params = (
        request.args if request.method == 'GET' else request.form
    )

    # Skip pre-request actions if verifying session
    if '/session' in request.path and not valid_user_session(session):
        return

    default_config = json.load(open(app.config['DEFAULT_CONFIG'])) \
        if os.path.exists(app.config['DEFAULT_CONFIG']) else {}

    # Generate session values for user if unavailable
    if (not valid_user_session(session) and
            'cookies_disabled' not in request.args):
        session['config'] = default_config
        session['uuid'] = str(uuid.uuid4())
        session['key'] = generate_user_key()

        # Skip checking for session on any searches that don't
        # require a valid session
        if (not Endpoint.autocomplete.in_path(request.path) and
                not Endpoint.healthz.in_path(request.path) and
                not Endpoint.opensearch.in_path(request.path)):
            return redirect(url_for(
                'session_check',
                session_id=session['uuid'],
                follow=get_request_url(request.url)), code=307)
        else:
            g.user_config = Config(**session['config'])
    elif 'cookies_disabled' not in request.args:
        # Set session as permanent
        session.permanent = True
        app.permanent_session_lifetime = timedelta(days=365)
        g.user_config = Config(**session['config'])
    else:
        # User has cookies disabled, fall back to immutable default config
        session.pop('_permanent', None)
        g.user_config = Config(**default_config)

    if not g.user_config.url:
        g.user_config.url = get_request_url(request.url_root)

    g.user_request = Request(
        request.headers.get('User-Agent'),
        get_request_url(request.url_root),
        config=g.user_config)

    g.app_location = g.user_config.url

    # Attempt to reload bangs json if not generated yet
    if not bang_json and os.path.getsize(app.config['BANG_FILE']) > 4:
        try:
            bang_json = json.load(open(app.config['BANG_FILE']))
        except json.decoder.JSONDecodeError:
            # Ignore decoding error, can occur if file is still
            # being written
            pass


@app.after_request
def after_request_func(resp):
    resp.headers['X-Content-Type-Options'] = 'nosniff'
    resp.headers['X-Frame-Options'] = 'DENY'

    if os.getenv('WHOOGLE_CSP', False):
        resp.headers['Content-Security-Policy'] = app.config['CSP']
        if os.environ.get('HTTPS_ONLY', False):
            resp.headers['Content-Security-Policy'] += \
                'upgrade-insecure-requests'

    return resp


@app.errorhandler(404)
def unknown_page(e):
    app.logger.warn(e)
    return redirect(g.app_location)


@app.route(f'/{Endpoint.healthz}', methods=['GET'])
def healthz():
    return ''


@app.route(f'/{Endpoint.session}/<session_id>', methods=['GET', 'PUT', 'POST'])
def session_check(session_id):
    if 'uuid' in session and session['uuid'] == session_id:
        session['valid'] = True
        return redirect(request.args.get('follow'), code=307)
    else:
        follow_url = request.args.get('follow')
        req = PreparedRequest()
        req.prepare_url(follow_url, {'cookies_disabled': 1})
        session.pop('_permanent', None)
        return redirect(req.url, code=307)


@app.route('/', methods=['GET'])
@app.route(f'/{Endpoint.home}', methods=['GET'])
@auth_required
def index():
    # Redirect if an error was raised
    if 'error_message' in session and session['error_message']:
        error_message = session['error_message']
        session['error_message'] = ''
        return render_template('error.html', error_message=error_message)

    return render_template('index.html',
                           has_update=app.config['HAS_UPDATE'],
                           languages=app.config['LANGUAGES'],
                           countries=app.config['COUNTRIES'],
                           themes=app.config['THEMES'],
                           autocomplete_enabled=autocomplete_enabled,
                           translation=app.config['TRANSLATIONS'][
                               g.user_config.get_localization_lang()
                           ],
                           logo=render_template(
                               'logo.html',
                               dark=g.user_config.dark),
                           config_disabled=(
                                   app.config['CONFIG_DISABLE'] or
                                   not valid_user_session(session) or
                                   'cookies_disabled' in request.args),
                           config=g.user_config,
                           tor_available=int(os.environ.get('TOR_AVAILABLE')),
                           version_number=app.config['VERSION_NUMBER'])


@app.route(f'/{Endpoint.opensearch}', methods=['GET'])
def opensearch():
    opensearch_url = g.app_location
    if opensearch_url.endswith('/'):
        opensearch_url = opensearch_url[:-1]

    # Enforce https for opensearch template
    if needs_https(opensearch_url):
        opensearch_url = opensearch_url.replace('http://', 'https://', 1)

    get_only = g.user_config.get_only or 'Chrome' in request.headers.get(
        'User-Agent')

    return render_template(
        'opensearch.xml',
        main_url=opensearch_url,
        request_type='' if get_only else 'method="post"'
    ), 200, {'Content-Type': 'application/xml'}


@app.route(f'/{Endpoint.search_html}', methods=['GET'])
def search_html():
    search_url = g.app_location
    if search_url.endswith('/'):
        search_url = search_url[:-1]
    return render_template('search.html', url=search_url)


@app.route(f'/{Endpoint.autocomplete}', methods=['GET', 'POST'])
def autocomplete():
    if os.getenv(ac_var) and not read_config_bool(ac_var):
        return jsonify({})

    q = g.request_params.get('q')
    if not q:
        # FF will occasionally (incorrectly) send the q field without a
        # mimetype in the format "b'q=<query>'" through the request.data field
        q = str(request.data).replace('q=', '')

    # Search bangs if the query begins with "!", but not "! " (feeling lucky)
    if q.startswith('!') and len(q) > 1 and not q.startswith('! '):
        return jsonify([q, [bang_json[_]['suggestion'] for _ in bang_json if
                            _.startswith(q)]])

    if not q and not request.data:
        return jsonify({'?': []})
    elif request.data:
        q = urlparse.unquote_plus(
            request.data.decode('utf-8').replace('q=', ''))

    # Return a list of suggestions for the query
    #
    # Note: If Tor is enabled, this returns nothing, as the request is
    # almost always rejected
    return jsonify([
        q,
        g.user_request.autocomplete(q) if not g.user_config.tor else []
    ])


@app.route(f'/{Endpoint.search}', methods=['GET', 'POST'])
@session_required
@auth_required
def search():
    # Update user config if specified in search args
    g.user_config = g.user_config.from_params(g.request_params)

    search_util = Search(request, g.user_config, g.session_key)
    query = search_util.new_search_query()

    bang = resolve_bang(query, bang_json)
    if bang:
        return redirect(bang)

    # Redirect to home if invalid/blank search
    if not query:
        return redirect(url_for('.index'))

    # Generate response and number of external elements from the page
    try:
        response = search_util.generate_response()
    except TorError as e:
        session['error_message'] = e.message + (
            "\\n\\nTor config is now disabled!" if e.disable else "")
        session['config']['tor'] = False if e.disable else session['config'][
            'tor']
        return redirect(url_for('.index'))

    if search_util.feeling_lucky:
        return redirect(response, code=303)

    # If the user is attempting to translate a string, determine the correct
    # string for formatting the lingva.ml url
    localization_lang = g.user_config.get_localization_lang()
    translation = app.config['TRANSLATIONS'][localization_lang]
    translate_to = localization_lang.replace('lang_', '')

    # Return 503 if temporarily blocked by captcha
    if has_captcha(str(response)):
        return render_template(
            'error.html',
            blocked=True,
            error_message=translation['ratelimit'],
            translation=translation,
            farside='https://farside.link',
            config=g.user_config,
            query=urlparse.unquote(query),
            params=g.user_config.to_params()), 503
    response = bold_search_terms(response, query)

    # Feature to display IP address
    if search_util.check_kw_ip():
        html_soup = bsoup(str(response), 'html.parser')
        response = add_ip_card(html_soup, get_client_ip(request))

    # Update tabs content
    tabs = get_tabs_content(app.config['HEADER_TABS'],
                            search_util.full_query,
                            search_util.search_type,
                            translation)

    # Feature to display currency_card
    conversion = check_currency(str(response))
    if conversion:
        html_soup = bsoup(str(response), 'html.parser')
        response = add_currency_card(html_soup, conversion)

    return render_template(
        'display.html',
        has_update=app.config['HAS_UPDATE'],
        query=urlparse.unquote(query),
        search_type=search_util.search_type,
        config=g.user_config,
        autocomplete_enabled=autocomplete_enabled,
        lingva_url=app.config['TRANSLATE_URL'],
        translation=translation,
        translate_to=translate_to,
        translate_str=query.replace(
            'translate', ''
        ).replace(
            translation['translate'], ''
        ),
        is_translation=any(
            _ in query.lower() for _ in [translation['translate'], 'translate']
        ) and not search_util.search_type,  # Standard search queries only
        response=response,
        version_number=app.config['VERSION_NUMBER'],
        search_header=render_template(
            'header.html',
            config=g.user_config,
            logo=render_template('logo.html', dark=g.user_config.dark),
            query=urlparse.unquote(query),
            search_type=search_util.search_type,
            mobile=g.user_request.mobile,
            tabs=tabs))


@app.route(f'/{Endpoint.config}', methods=['GET', 'POST', 'PUT'])
@session_required
@auth_required
def config():
    config_disabled = (
            app.config['CONFIG_DISABLE'] or
            not valid_user_session(session))
    if request.method == 'GET':
        return json.dumps(g.user_config.__dict__)
    elif request.method == 'PUT' and not config_disabled:
        if 'name' in request.args:
            config_pkl = os.path.join(
                app.config['CONFIG_PATH'],
                request.args.get('name'))
            session['config'] = (pickle.load(open(config_pkl, 'rb'))
                                 if os.path.exists(config_pkl)
                                 else session['config'])
            return json.dumps(session['config'])
        else:
            return json.dumps({})
    elif not config_disabled:
        config_data = request.form.to_dict()
        if 'url' not in config_data or not config_data['url']:
            config_data['url'] = g.user_config.url

        # Save config by name to allow a user to easily load later
        if 'name' in request.args:
            pickle.dump(
                config_data,
                open(os.path.join(
                    app.config['CONFIG_PATH'],
                    request.args.get('name')), 'wb'))

        session['config'] = config_data
        return redirect(config_data['url'])
    else:
        return redirect(url_for('.index'), code=403)


@app.route(f'/{Endpoint.imgres}')
@session_required
@auth_required
def imgres():
    return redirect(request.args.get('imgurl'))


@app.route(f'/{Endpoint.element}')
@session_required
@auth_required
def element():
    element_url = src_url = request.args.get('url')
    if element_url.startswith('gAAAAA'):
        try:
            cipher_suite = Fernet(g.session_key)
            src_url = cipher_suite.decrypt(element_url.encode()).decode()
        except (InvalidSignature, InvalidToken) as e:
            return render_template(
                'error.html',
                error_message=str(e)), 401

    src_type = request.args.get('type')

    try:
        file_data = g.user_request.send(base_url=src_url).content
        tmp_mem = io.BytesIO()
        tmp_mem.write(file_data)
        tmp_mem.seek(0)

        return send_file(tmp_mem, mimetype=src_type)
    except exceptions.RequestException:
        pass

    empty_gif = base64.b64decode(
        'R0lGODlhAQABAIAAAP///////yH5BAEKAAEALAAAAAABAAEAAAICTAEAOw==')
    return send_file(io.BytesIO(empty_gif), mimetype='image/gif')


@app.route(f'/{Endpoint.window}')
@session_required
@auth_required
def window():
    target_url = request.args.get('location')
    if target_url.startswith('gAAAAA'):
        cipher_suite = Fernet(g.session_key)
        target_url = cipher_suite.decrypt(target_url.encode()).decode()

    content_filter = Filter(
        g.session_key,
        root_url=request.url_root,
        config=g.user_config)
    target = urlparse.urlparse(target_url)
    host_url = f'{target.scheme}://{target.netloc}'

    get_body = g.user_request.send(base_url=target_url).text

    results = bsoup(get_body, 'html.parser')
    src_attrs = ['src', 'href', 'srcset', 'data-srcset', 'data-src']

    # Parse HTML response and replace relative links w/ absolute
    for element in results.find_all():
        for attr in src_attrs:
            if not element.has_attr(attr) or not element[attr].startswith('/'):
                continue

            element[attr] = host_url + element[attr]

    # Replace or remove javascript sources
    for script in results.find_all('script', {'src': True}):
        if 'nojs' in request.args:
            script.decompose()
        else:
            content_filter.update_element_src(script, 'application/javascript')

    # Replace all possible image attributes
    img_sources = ['src', 'data-src', 'data-srcset', 'srcset']
    for img in results.find_all('img'):
        _ = [
            content_filter.update_element_src(img, 'image/png', attr=_)
            for _ in img_sources if img.has_attr(_)
        ]

    # Replace all stylesheet sources
    for link in results.find_all('link', {'href': True}):
        content_filter.update_element_src(link, 'text/css', attr='href')

    # Use anonymous view for all links on page
    for a in results.find_all('a', {'href': True}):
        a['href'] = f'{Endpoint.window}?location=' + a['href'] + (
            '&nojs=1' if 'nojs' in request.args else '')

    # Remove all iframes -- these are commonly used inside of <noscript> tags
    # to enforce loading Google Analytics
    for iframe in results.find_all('iframe'):
        iframe.decompose()

    return render_template(
        'display.html',
        response=results,
        translation=app.config['TRANSLATIONS'][
            g.user_config.get_localization_lang()
        ]
    )


def run_app() -> None:
    parser = argparse.ArgumentParser(
        description='Whoogle Search console runner')
    parser.add_argument(
        '--port',
        default=5000,
        metavar='<port number>',
        help='Specifies a port to run on (default 5000)')
    parser.add_argument(
        '--host',
        default='127.0.0.1',
        metavar='<ip address>',
        help='Specifies the host address to use (default 127.0.0.1)')
    parser.add_argument(
        '--unix-socket',
        default='',
        metavar='</path/to/unix.sock>',
        help='Listen for app on unix socket instead of host:port')
    parser.add_argument(
        '--debug',
        default=False,
        action='store_true',
        help='Activates debug mode for the server (default False)')
    parser.add_argument(
        '--https-only',
        default=False,
        action='store_true',
        help='Enforces HTTPS redirects for all requests')
    parser.add_argument(
        '--userpass',
        default='',
        metavar='<username:password>',
        help='Sets a username/password basic auth combo (default None)')
    parser.add_argument(
        '--proxyauth',
        default='',
        metavar='<username:password>',
        help='Sets a username/password for a HTTP/SOCKS proxy (default None)')
    parser.add_argument(
        '--proxytype',
        default='',
        metavar='<socks4|socks5|http>',
        help='Sets a proxy type for all connections (default None)')
    parser.add_argument(
        '--proxyloc',
        default='',
        metavar='<location:port>',
        help='Sets a proxy location for all connections (default None)')
    args = parser.parse_args()

    if args.userpass:
        user_pass = args.userpass.split(':')
        os.environ['WHOOGLE_USER'] = user_pass[0]
        os.environ['WHOOGLE_PASS'] = user_pass[1]

    if args.proxytype and args.proxyloc:
        if args.proxyauth:
            proxy_user_pass = args.proxyauth.split(':')
            os.environ['WHOOGLE_PROXY_USER'] = proxy_user_pass[0]
            os.environ['WHOOGLE_PROXY_PASS'] = proxy_user_pass[1]
        os.environ['WHOOGLE_PROXY_TYPE'] = args.proxytype
        os.environ['WHOOGLE_PROXY_LOC'] = args.proxyloc

    if args.https_only:
        os.environ['HTTPS_ONLY'] = '1'

    if args.debug:
        app.run(host=args.host, port=args.port, debug=args.debug)
    elif args.unix_socket:
        waitress.serve(app, unix_socket=args.unix_socket)
    else:
        waitress.serve(
            app,
            listen="{}:{}".format(args.host, args.port),
            url_prefix=os.environ.get('WHOOGLE_URL_PREFIX', ''))