#!/usr/bin/env python2
# -*- coding: utf-8 -*-
import sqlite3
import threading
import traceback
import json
import requests
import os
import logging

from flask import Flask, render_template, abort, g, \
    redirect, request, flash, url_for, make_response
from datetime import datetime
from time import sleep, time, mktime
from collections import namedtuple
from urllib import urlencode

from spaceauth import SpaceAuth, login_required, current_user, cap_required

app = Flask('at')
app.config.from_pyfile('at.cfg')
app.jinja_env.add_extension('jinja2.ext.i18n')
app.jinja_env.install_null_translations()
app.updater = None

if app.config.get('PROXY_FIX'):
    from werkzeug.contrib.fixers import ProxyFix
    app.wsgi_app = ProxyFix(app.wsgi_app)

auth = SpaceAuth(app)


from functools import wraps


def v4addr():
    if request.headers.getlist("X-Forwarded-For"):
        r_addr = request.headers.getlist("X-Forwarded-For")[-1]
    else:
        r_addr = request.remote_addr
    if r_addr.startswith('::ffff:'):
        r_addr = r_addr[7:]
    return r_addr


def restrict_ip(prefix='', exclude=[]):
    def decorator(f):
        @wraps(f)
        def func(*a, **kw):
            r_addr = v4addr()
            if not r_addr.startswith(prefix) or r_addr in exclude:
                app.logger.info('got IP %s, rejecting', r_addr)
                abort(403)

            return f(*a, **kw)
        return func
    return decorator


def req_to_ctx():
    return dict(request.form.iteritems())


@app.template_filter('strfts')
def strfts(ts, format='%d/%m/%Y %H:%M'):
    return datetime.fromtimestamp(ts).strftime(format)


@app.template_filter('wikiurl')
def wikiurl(user):
    return app.config['WIKI_URL'] % {'login': user}


@app.before_request
def make_connection():
    conn = sqlite3.connect(app.config['DB'])
    conn.row_factory = sqlite3.Row
    conn.isolation_level = None  # for autocommit mode
    g.db = conn


@app.teardown_request
def close_connection(exception):
    g.db.close()


DeviceInfo = namedtuple('DeviceInfo', ['hwaddr', 'name', 'owner', 'ignored'])


def get_device_info(conn, hwaddr):
    return list(get_device_infos(conn, (hwaddr,)))[0]


def get_device_infos(conn, hwaddrs):
    in_clause = '({})'.format(', '.join(['?'] * len(hwaddrs)))
    stmt = '''select hwaddr, name, ignored, owner from
        devices where devices.hwaddr in ''' + in_clause
    for row in conn.execute(stmt, hwaddrs):
        owner = row['owner'] or ''
        ignored = row['ignored']
        yield DeviceInfo(row['hwaddr'], row['name'], owner, ignored)


class Updater(threading.Thread):
    def __init__(self,  timeout, lease_offset=0, *a, **kw):
        self.timeout = timeout
        self.lock = threading.Lock()
        self.lease_offset = lease_offset
        self.active = {}
        threading.Thread.__init__(self, *a, **kw)
        self.daemon = True

    def purge_stale(self):
        now = time()
        for addr, (atime, ip, name) in self.active.items():
            if now - atime > self.timeout:
                del self.active[addr]

    def get_active_devices(self):
        self.lock.acquire()
        self.purge_stale()
        r = dict(self.active)
        self.lock.release()
        return r

    def get_device(self, ip):
        active_devices = self.get_active_devices().iteritems()
        for hwaddr, (atime, dip, name) in active_devices:
            if ip == dip:
                return hwaddr, name
        return None, None

    def update(self, hwaddr, atime=None, ip=None, name=None):
        if atime:
            atime -= self.lease_offset
        else:
            atime = time()
        self.lock.acquire()
        if hwaddr not in self.active or self.active[hwaddr][0] < atime:
            self.active[hwaddr] = (atime, ip, name)
            app.logger.info('updated %s with atime %s and ip %s',
                            hwaddr, strfts(atime), ip)
        self.lock.release()


class CapUpdater(Updater):
    def __init__(self, cap_file, *a, **kw):
        self.cap_file = cap_file
        Updater.__init__(self, *a, **kw)

    def run(self):
        while True:
            try:
                with open(self.cap_file, 'r', buffering=0) as f:
                    app.logger.info('Updater ready on cap file %s',
                                    self.cap_file)
                    lines = [l.strip() for l in f.read().split('\n')]
                    for hwaddr in lines:
                        if hwaddr:
                            self.update(hwaddr)
                app.logger.warning('Cap file %s closed, reopening',
                                   self.cap_file)
            except Exception as e:
                app.logger.error('Updater got an exception:\n' +
                                 traceback.format_exc(e))
                sleep(10.0)


class MtimeUpdater(Updater):
    def __init__(self, lease_file, *a, **kw):
        self.lease_file = lease_file
        self.last_modified = 0
        Updater.__init__(self, *a, **kw)

    def file_changed(self, f):
        pass

    def _trigger_update(self):
        app.logger.info('Lease file changed, updating')
        with open(self.lease_file, 'r') as f:
            self.file_changed(f)

    def run(self):
        while True:
            try:
                mtime = os.stat(self.lease_file).st_mtime
                if mtime > self.last_modified:
                    self._trigger_update()
                self.last_modified = mtime
                sleep(3.0)
            except Exception as e:
                app.logger.error('Updater got an exception:\n' +
                                 traceback.format_exc(e))
                sleep(10.0)


class DnsmasqUpdater(MtimeUpdater):
    def file_changed(self, f):
        for line in f:
            ts, hwaddr, ip, name, client_id = line.split(' ')
            self.update(hwaddr, int(ts), ip, name)


class DhcpdUpdater(MtimeUpdater):
    def file_changed(self, f):
        lease = False
        # for use by next-line logic
        ip = None
        hwaddr = None
        atime = None
        for line in f:
            line = line.split('#')[0]
            cmd = line.strip().split()
            if not cmd:
                continue
            if lease:
                field = cmd[0]
                if(field == 'starts'):
                    dt = datetime.strptime(' '.join(cmd[2:]),
                                           '%Y/%m/%d %H:%M:%S;')
                    atime = mktime(dt.utctimetuple())
                if(field == 'client-hostname'):
                    name = cmd[1][1:-2]
                if(field == 'hardware'):
                    hwaddr = cmd[2][:-1]
                if(field.startswith('}')):
                    lease = False
                    if hwaddr is not None and atime is not None:
                        self.update(hwaddr, atime, ip, name)
                    hwaddr, atime = None, None
            elif cmd[0] == 'lease':
                ip = cmd[1]
                name, hwaddr, atime = [None] * 3
                lease = True


@app.route('/')
def main_view():
    return render_template('main.html', **now_at())


@app.route('/api')
def list_all():
    data = now_at()

    def prettify_user((user, atime)):
        return {
            'login': user,
            'timestamp': atime,
            'pretty_time': strfts(atime),
        }
    result = {}
    result['users'] = map(prettify_user, data.pop('users'))
    result.update((k, len(v)) for k, v in data.items())
    res = make_response(json.dumps(result), 200)
    res.headers['Access-Control-Allow-Origin'] = '*'
    return res


def now_at():
    result = dict()
    devices = app.updater.get_active_devices()
    device_infos = list(get_device_infos(g.db, devices.keys()))
    device_infos.sort(key=lambda di: devices.__getitem__)
    unknown = set(devices.keys()) - set(d.hwaddr for d in device_infos)
    # das kektop sorting maschine
    for name, prefixes in app.config['SPECIAL_DEVICES'].items():
        result[name] = set()
        for u in unknown.copy():
            if u.startswith(prefixes):
                result[name].add(u)
                unknown.discard(u)

    result['unknown'] = unknown

    users = {}
    for info in device_infos:
        if info.owner not in users:
            users[info.owner] = devices[info.hwaddr][0]
    result['users'] = sorted(users.items(), key=lambda (u, a): a, reverse=True)

    return result


restrict_to_hs = restrict_ip(prefix=app.config['CLAIMABLE_PREFIX'],
                             exclude=app.config['CLAIMABLE_EXCLUDE'])


@app.route('/claim', methods=['GET'])
@restrict_to_hs
@login_required
def claim_form():
    hwaddr, name = app.updater.get_device(v4addr())
    return render_template('claim.html', hwaddr=hwaddr, name=name)


@app.route('/claim', methods=['POST'])
@restrict_to_hs
@login_required
def claim():
    hwaddr, lease_name = app.updater.get_device(v4addr())
    ctx = None
    if not hwaddr:
        ctx = dict(error='Invalid device.')
    else:
        login = current_user.id
        try:
            g.db.execute('''
insert into devices (hwaddr, name, owner, ignored) values (?, ?, ?, ?)''',
                         [hwaddr, request.form['name'], login, False])
            ctx = {}
        except sqlite3.Error:
            error = 'Could not add device! Perhaps someone claimed it?'
            ctx = dict(error=error)
    return render_template('post_claim.html', **ctx)


def get_user_devices(conn, user):
    devs = conn.execute('select hwaddr, name, ignored from devices where\
 owner = ?', [user])
    device_info = []
    for row in devs:
        di = DeviceInfo(row['hwaddr'], row['name'], user, row['ignored'])
        device_info.append(di)
    return device_info


@app.route('/account', methods=['GET'])
@login_required
def account():
    devices = get_user_devices(g.db, current_user.id)
    return render_template('account.html', devices=devices)


def set_ignored(conn, hwaddr, user, value):
    return conn.execute('''
update devices set ignored = ? where hwaddr = ? and owner = ?''',
                        [value, hwaddr, user])


def delete_device(conn, hwaddr, user):
    return conn.execute('''
delete from devices where hwaddr = ? and owner = ?''',
                        [hwaddr, user])


@app.route('/devices/<id>/<action>/')
@login_required
def device(id, action):
    user = current_user.id
    if action == 'hide':
        set_ignored(g.db, id, user, True)
    if action == 'show':
        set_ignored(g.db, id, user, False)
    if action == 'delete':
        delete_device(g.db, id, user)
    return redirect(url_for('account'))


@app.route('/admin')
@cap_required('staff')
def admin():
    data = now_at()
    return render_template('admin.html', data=data)


@app.before_first_request
def setup():
    updater = DhcpdUpdater(app.config['LEASE_FILE'], app.config['TIMEOUT'],
                           app.config['LEASE_OFFSET'])
    updater.start()
    app.updater = updater


port = 8080
if __name__ == '__main__':
    app.logger.setLevel(logging.DEBUG)
    app.run('0.0.0.0', 8080, debug=True)