import logging
logger = logging.getLogger(__name__)

import io
import json
import requests
import time
from datetime import datetime, timedelta
from rest_framework.exceptions import ValidationError
from rest_framework.views import exception_handler
from dateutil import relativedelta
from uuid import uuid4
from PIL import Image, ImageDraw, ImageFont, ImageOps, JpegImagePlugin
JpegImagePlugin._getmp = lambda x: None
from bleach.sanitizer import Cleaner
from PyPDF2 import PdfFileWriter, PdfFileReader
from reportlab.pdfgen import canvas
from reportlab.lib.pagesizes import letter

from django.db.models import Sum
from django.core.cache import cache
from django.utils.timezone import now, pytz

from . import models, serializers, utils_ldap, utils_stats, utils_auth, utils, utils_email
from .. import settings, secrets

STATIC_FOLDER = 'data/static/'

TIMEZONE_CALGARY = pytz.timezone('America/Edmonton')

def today_alberta_tz():
    return datetime.now(TIMEZONE_CALGARY).date()

def now_alberta_tz():
    return datetime.now(TIMEZONE_CALGARY)

def alert_tanner(message):
    try:
        logger.info('Alerting Tanner: ' + message)
        params = dict(spaceport=message)
        requests.get('https://tbot.tannercollin.com/message', params=params, timeout=4)
    except BaseException as e:
        logger.error('Problem alerting Tanner: ' + str(e))

def spaceporter_host(message):
    logger.info('Spaceporter bot sending to host chat: ' + message)

    if secrets.SPACEPORTER_HOST_TOKEN:
        url = 'https://forum.protospace.ca/chat/hooks/{}.json'.format(
            secrets.SPACEPORTER_HOST_TOKEN,
        )
    else:
        logger.info('Aborting Spaceporter bot message, no token.')
        return

    try:
        data = dict(text=message)
        requests.post(url, json=data, timeout=4)
    except BaseException as e:
        logger.error('Problem with bot: ' + str(e))

def num_months_spanned(d1, d2):
    '''
    Return number of month thresholds two dates span.
    Order of arguments is same as subtraction
    ie. Feb 2, Jan 29 returns 1
    '''
    return (d1.year - d2.year) * 12 + d1.month - d2.month

def num_months_difference(d1, d2):
    '''
    Return number of whole months between two dates.
    Order of arguments is same as subtraction
    ie. Feb 2, Jan 29 returns 0
    '''
    r = relativedelta.relativedelta(d1, d2)
    return r.months + 12 * r.years

def calc_member_status(expire_date, fake_date=None):
    '''
    Return: member status
    '''
    today = fake_date or today_alberta_tz()

    difference = num_months_difference(expire_date, today)

    if today + timedelta(days=29) < expire_date:
        return 'Prepaid'
    elif difference <= -3:
        return 'Expired Member'
    elif today - timedelta(days=29) >= expire_date:
        return 'Overdue'
    elif today < expire_date:
        return 'Current'
    elif today >= expire_date:
        return 'Due'
    else:
        raise()

def add_months(date, num_months):
    return date + relativedelta.relativedelta(months=num_months)

def tally_membership_months(member, fake_date=None):
    '''
    Sum together member's dues and calculate their new expire date and status
    Doesn't work if member is paused.
    '''
    if member.paused_date: return False

    start_date = member.current_start_date
    if not start_date: return False

    txs = models.Transaction.objects.filter(
        user__member=member,
        date__gte=start_date,
    )
    total_months_agg = txs.aggregate(Sum('number_of_membership_months'))
    total_months = total_months_agg['number_of_membership_months__sum'] or 0

    expire_date = add_months(start_date, total_months)
    status = calc_member_status(expire_date, fake_date)

    if member.expire_date != expire_date or member.status != status:
        previous_status = member.status

        member.expire_date = expire_date
        member.status = status

        if status == 'Expired Member':
            member.paused_date = today_alberta_tz()
            msg = 'Member has expired: {} {}'.format(member.preferred_name, member.last_name)
            alert_tanner(msg)
            logger.info(msg)

        if status == 'Overdue':
            if previous_status == 'Due':
                msg = 'Member has become Overdue: {} {}'.format(member.preferred_name, member.last_name)
                alert_tanner(msg)
                logger.info(msg)

                utils_email.send_overdue_email(member)
            else:
                logger.info('Skipping email because member wasn\'t due before.')

        member.save()
        logging.debug('Tallied %s membership months: updated.', member)
    else:
        logging.debug('Tallied %s membership months: no changes.', member)

    return True


def gen_search_strings():
    '''
    Generate a cache dict of names to member ids for rapid string matching
    '''
    start = time.time()

    search_strings = {}
    for m in models.Member.objects.order_by('-expire_date').prefetch_related('user__storage'):
        string = '{} {} | {} {}'.format(
            m.preferred_name,
            m.last_name,
            m.first_name,
            m.last_name,
        )

        string += ' | ' + m.user.email

        if m.discourse_username:
            string += ' | ' + m.discourse_username

        string += ' | ' + str(m.id)

        for s in m.user.storage.all():
            string += ' | ' + s.shelf_id

        string = string.lower()
        search_strings[string] = m.id

    cache.set('search_strings', search_strings)

    logger.info('Generated search strings in %s s.', time.time() - start)


LARGE_SIZE = 1080
MEDIUM_SIZE = 220
SMALL_SIZE = 110

def process_image_upload(upload, crop):
    '''
    Save an image upload in small, medium, large sizes and return filenames
    '''
    try:
        pic = Image.open(upload)
    except OSError:
        raise serializers.ValidationError(dict(non_field_errors='Invalid image file.'))

    logging.info('Detected format: %s', pic.format)

    if pic.format == 'PNG':
        ext = '.png'
    elif pic.format == 'JPEG':
        ext = '.jpg'
    else:
        raise serializers.ValidationError(dict(non_field_errors='Image must be a jpg or png.'))

    pic = ImageOps.exif_transpose(pic)

    if crop:
        crop = json.loads(crop)
        pic_x, pic_y = pic.size
        left = pic_x * crop['x']/100.0
        top = pic_y * crop['y']/100.0
        right = left + pic_x * crop['width']/100.0
        bottom = top + pic_y * crop['height']/100.0
        pic = pic.crop((left, top, right, bottom))

    large = str(uuid4()) + ext
    pic.thumbnail([LARGE_SIZE, LARGE_SIZE], Image.ANTIALIAS)
    pic.save(STATIC_FOLDER + large)

    medium = str(uuid4()) + ext
    pic.thumbnail([MEDIUM_SIZE, MEDIUM_SIZE], Image.ANTIALIAS)
    pic.save(STATIC_FOLDER + medium)

    small = str(uuid4()) + ext
    pic.thumbnail([SMALL_SIZE, SMALL_SIZE], Image.ANTIALIAS)
    pic.save(STATIC_FOLDER + small)

    return small, medium, large


GARDEN_MEDIUM_SIZE = 500

def process_garden_image(upload):
    try:
        pic = Image.open(upload)
    except OSError:
        raise serializers.ValidationError(dict(non_field_errors='Invalid image file.'))

    logging.debug('Detected format: %s', pic.format)

    if pic.format == 'PNG':
        ext = '.png'
    elif pic.format == 'JPEG':
        ext = '.jpg'
    else:
        raise serializers.ValidationError(dict(non_field_errors='Image must be a jpg or png.'))

    pic = ImageOps.exif_transpose(pic)

    draw = ImageDraw.Draw(pic)

    timestamp = now_alberta_tz().strftime('%a %b %-d, %Y  %-I:%M %p')

    font = ImageFont.truetype('DejaVuSans.ttf', 60)
    draw.text((10, 10), timestamp, (0,0,0), font=font)

    large = 'garden-large' + ext
    pic.save(STATIC_FOLDER + large)

    medium = 'garden-medium' + ext
    pic.thumbnail([GARDEN_MEDIUM_SIZE, GARDEN_MEDIUM_SIZE], Image.ANTIALIAS)
    pic.save(STATIC_FOLDER + medium)

    return medium, large


CARD_TEMPLATE_FILE = 'misc/member_card_template.jpg'
CARD_PHOTO_SIZE = 425
CARD_PHOTO_MARGIN_TOP = 75
CARD_PHOTO_MARGIN_SIDE = 30
CARD_TEXT_SIZE_LIMIT = 550

def gen_card_photo(member):
    card_template = Image.open(CARD_TEMPLATE_FILE)

    member_photo = Image.open(STATIC_FOLDER + member.photo_large)
    member_photo.thumbnail([CARD_PHOTO_SIZE, CARD_PHOTO_SIZE], Image.ANTIALIAS)
    member_photo = ImageOps.expand(member_photo, border=10)
    mx, my = member_photo.size

    x = CARD_PHOTO_MARGIN_SIDE
    y = CARD_PHOTO_MARGIN_TOP
    card_template.paste(member_photo, (x, y))

    draw = ImageDraw.Draw(card_template)

    # check font size
    font_sizes = (60, 72)
    font = ImageFont.truetype('DejaVuSans-Bold.ttf', font_sizes[1])
    size = draw.textsize(str(member.last_name), font=font)
    if size[0] > CARD_TEXT_SIZE_LIMIT:
        font_sizes = (36, 48)

    font = ImageFont.truetype('DejaVuSans.ttf', font_sizes[0])
    x = CARD_PHOTO_MARGIN_SIDE
    y = my + CARD_PHOTO_MARGIN_TOP + CARD_PHOTO_MARGIN_SIDE
    draw.text((x, y), str(member.preferred_name), (0,0,0), font=font)

    font = ImageFont.truetype('DejaVuSans-Bold.ttf', font_sizes[1])
    y = my + CARD_PHOTO_MARGIN_TOP + CARD_PHOTO_MARGIN_SIDE + font_sizes[1]
    draw.text((x, y), str(member.last_name), (0,0,0), font=font)

    font = ImageFont.truetype('DejaVuSans.ttf', 36)
    draw.text((x, 800), 'Joined: ' + str(member.application_date or 'Unknown'), (0,0,0), font=font)
    y = CARD_PHOTO_MARGIN_SIDE
    draw.text((475, y), str(member.id), (0,0,0), font=font)

    bio = io.BytesIO()
    card_template.save(bio, 'JPEG', quality=95)
    bio.seek(0)

    return bio


ALLOWED_TAGS = [
    'h3',
    'p',
    'br',
    'strong',
    'em',
    'u',
    'code',
    'ol',
    'li',
    'ul',
    'a',
]

clean = Cleaner(tags=ALLOWED_TAGS).clean


def is_request_from_protospace(request):
    # TODO: pull to config
    whitelist = ['24.66.110.96', '205.233.15.76', '205.233.15.69', '70.75.142.145']

    if settings.DEBUG:
        return True

    # set (not appended) directly by nginx so we can trust it
    real_ip = request.META.get('HTTP_X_REAL_IP', False)

    return real_ip in whitelist

def create_new_member(data, user):
    members = models.Member.objects
    if members.filter(old_email__iexact=data['email']).exists():
        msg = 'Account was found in old portal.'
        logger.info(msg)
        raise ValidationError(dict(email=msg))

    if utils_ldap.is_configured():
        if data['request_id']: utils_stats.set_progress(data['request_id'], 'Creating LDAP account...')
        result = utils_ldap.find_user(user.username)
        if result == 200:
            msg = 'Username was found in old portal.'
            logger.info(msg)
            raise ValidationError(dict(username=msg))
        elif result == 404:
            pass
        else:
            msg = 'Problem connecting to LDAP server.'
            alert_tanner(msg)
            logger.info(msg)
            raise ValidationError(dict(non_field_errors=msg))

        if utils_ldap.create_user(data) != 200:
            msg = 'Problem connecting to LDAP server: create.'
            alert_tanner(msg)
            logger.info(msg)
            raise ValidationError(dict(non_field_errors=msg))

    if data['request_id']: utils_stats.set_progress(data['request_id'], 'Creating new member...')

    models.Member.objects.create(
        user=user,
        first_name=data['first_name'],
        last_name=data['last_name'],
        preferred_name=data['preferred_name'],
    )

def register_user(data, user):
    data = data.copy()
    data['first_name'] = data['first_name'].title().strip()
    data['last_name'] = data['last_name'].title().strip()
    data['preferred_name'] = data['preferred_name'].title().strip()

    # Sometimes during demos, a user makes a fake account then then has to be cleaned out
    # Notify me that this has happened so I can go clean out the database
    if 'test' in data['username']:
        msg = 'Someone created a test account: {} {} {} {}'.format(
            data['username'],
            data['first_name'],
            data['last_name'],
            data['email'],
        )
        logger.info(msg)
        alert_tanner(msg)

    try:
        logger.info('Creating new member...')
        create_new_member(data, user)
    except:
        user.delete()
        raise

    auth_data = dict(
        username=data['username'],
        password=data['password1'],
        email=data['email'],
        first_name=data['preferred_name'],
    )

    if utils_auth.wiki_is_configured():
        if data['request_id']: utils_stats.set_progress(data['request_id'], 'Creating Wiki account...')
        if utils_auth.set_wiki_password(auth_data) != 200:
            msg = 'Problem connecting to Wiki Auth server: set.'
            utils.alert_tanner(msg)
            logger.info(msg)

    if utils_auth.discourse_is_configured():
        if data['request_id']: utils_stats.set_progress(data['request_id'], 'Creating Discourse account...')
        if utils_auth.set_discourse_password(auth_data) != 200:
            msg = 'Problem connecting to Discourse Auth server: set.'
            utils.alert_tanner(msg)
            logger.info(msg)
        if not user.member.discourse_username:
            user.member.discourse_username = user.username
            user.member.save()

    if utils_auth.discourse_is_configured():
        if data['request_id']: utils_stats.set_progress(data['request_id'], 'Adding to Discourse group...')
        if utils_auth.add_discourse_group_members('protospace_members', [data['username']]) != 200:
            msg = 'Problem connecting to Discourse Auth server: add.'
            utils.alert_tanner(msg)
            logger.info(msg)

    if data['request_id']: utils_stats.set_progress(data['request_id'], 'Sending welcome email...')
    try:
        utils_email.send_welcome_email(user.member)
    except BaseException as e:
        msg = 'Problem sending welcome email: ' + str(e)
        logger.exception(msg)
        alert_tanner(msg)


    if data['request_id']: utils_stats.set_progress(data['request_id'], 'Done!')

    gen_search_strings()

    cache.set('sign', 'Welcome to Protospace, {}!'.format(data['preferred_name']))


BLANK_FORM = 'misc/blank_member_form.pdf'
def gen_member_forms(member):
    serializer = serializers.MemberSerializer(member)
    data = serializer.data

    packet = io.BytesIO()
    can = canvas.Canvas(packet, pagesize=letter)
    can.drawString(34, 683, data['first_name'])
    can.drawString(218, 683, data['last_name'])
    can.drawString(403, 683, data['preferred_name'])
    can.drawString(34, 626, data['email'])
    can.drawString(332, 626, data['phone'])
    can.drawString(34, 570, data['emergency_contact_name'])
    can.drawString(332, 570, data['emergency_contact_phone'])
    can.save()
    packet.seek(0)
    info_pdf = PdfFileReader(packet)

    packet = io.BytesIO()
    can = canvas.Canvas(packet, pagesize=letter)
    can.drawRightString(600, 770, '{} {} ({})'.format(
        data['preferred_name'],
        data['last_name'],
        data['id'],
    ))
    can.save()
    packet.seek(0)
    topright_pdf = PdfFileReader(packet)

    existing_pdf = PdfFileReader(open(BLANK_FORM, 'rb'))
    output = PdfFileWriter()
    page = existing_pdf.getPage(0)
    page.mergePage(info_pdf.getPage(0))
    page.mergePage(topright_pdf.getPage(0))
    output.addPage(page)
    page = existing_pdf.getPage(1)
    page.mergePage(topright_pdf.getPage(0))
    output.addPage(page)
    page = existing_pdf.getPage(2)
    page.mergePage(topright_pdf.getPage(0))
    output.addPage(page)

    file_name = str(uuid4()) + '.pdf'
    outputStream = open(STATIC_FOLDER + file_name, 'wb')
    output.write(outputStream)

    member.member_forms = file_name
    member.save()

def custom_exception_handler(exc, context):
    response = exception_handler(exc, context)
    if response is not None:
        if hasattr(exc, 'detail'):
            logging.warning('Response: %s', json.dumps(exc.detail))
        else:
            logging.warning('Response: %s', exc)
    return response

def log_transaction(tx):
    msg = 'Transaction log | {} | {} | {} | {} | {} | {} | {} | {} | {}'.format(
        tx.id,
        tx.user.username,
        tx.user.member.id,
        tx.account_type,
        tx.amount,
        tx.protocoin,
        tx.category,
        tx.reference_number,
        tx.memo,
    )

    logging.info(msg)