import copy
import json
from collections import OrderedDict
from io import BytesIO
from typing import Tuple

from django import forms
from django.conf import settings
from django.contrib.staticfiles import finders
from django.core.files import File
from django.core.files.storage import default_storage
from django.db.models import Exists, OuterRef
from django.db.models.functions import Coalesce
from django.utils.translation import gettext as _, gettext_lazy
from jsonfallback.functions import JSONExtract
from reportlab.lib import pagesizes
from reportlab.lib.units import mm
from reportlab.pdfgen import canvas

from pretix.base.exporter import BaseExporter
from pretix.base.i18n import language
from pretix.base.models import Order, OrderPosition
from pretix.base.pdf import Renderer
from pretix.base.services.orders import OrderError
from pretix.base.settings import PERSON_NAME_SCHEMES
from pretix.plugins.badges.models import BadgeItem, BadgeLayout


def _renderer(event, layout):
    if layout is None:
        return None
    if isinstance(layout.background, File) and layout.background.name:
        bgf = default_storage.open(layout.background.name, "rb")
    else:
        bgf = open(finders.find('pretixplugins/badges/badge_default_a6l.pdf'), "rb")
    return Renderer(event, json.loads(layout.layout), bgf)


OPTIONS = OrderedDict([
    ('one', {
        'name': gettext_lazy('One badge per page'),
        'cols': 1,
        'rows': 1,
        'margins': [0, 0, 0, 0],
        'offsets': [0, 0],
        'pagesize': None,
    }),
    ('a4_a6l', {
        'name': gettext_lazy('4 landscape A6 pages on one A4 page'),
        'cols': 2,
        'rows': 2,
        'margins': [0 * mm, 0 * mm, 0 * mm, 0 * mm],
        'offsets': [pagesizes.landscape(pagesizes.A4)[0] / 2, pagesizes.landscape(pagesizes.A4)[1] / 2],
        'pagesize': pagesizes.landscape(pagesizes.A4),
    }),
    ('a4_a6p', {
        'name': gettext_lazy('4 portrait A6 pages on one A4 page'),
        'cols': 2,
        'rows': 2,
        'margins': [0 * mm, 0 * mm, 0 * mm, 0 * mm],
        'offsets': [pagesizes.portrait(pagesizes.A4)[0] / 2, pagesizes.portrait(pagesizes.A4)[0] / 2],
        'pagesize': pagesizes.portrait(pagesizes.A4),
    }),
    ('a4_a7l', {
        'name': gettext_lazy('8 landscape A7 pages on one A4 page'),
        'cols': 2,
        'rows': 4,
        'margins': [0 * mm, 0 * mm, 0 * mm, 0 * mm],
        'offsets': [pagesizes.portrait(pagesizes.A4)[0] / 2, pagesizes.portrait(pagesizes.A4)[1] / 4],
        'pagesize': pagesizes.portrait(pagesizes.A4),
    }),
    ('a4_a7p', {
        'name': gettext_lazy('8 portrait A7 pages on one A4 page'),
        'cols': 4,
        'rows': 2,
        'margins': [0 * mm, 0 * mm, 0 * mm, 0 * mm],
        'offsets': [pagesizes.landscape(pagesizes.A4)[0] / 4, pagesizes.landscape(pagesizes.A4)[0] / 2],
        'pagesize': pagesizes.landscape(pagesizes.A4),
    }),
    ('durable_54x90', {
        'name': 'DURABLE BADGEMAKER® 54 x 90 mm (1445-02)',
        'cols': 2,
        'rows': 5,
        'margins': [12 * mm, 15 * mm, 15 * mm, 15 * mm],
        'offsets': [90 * mm, 54 * mm],
        'pagesize': pagesizes.A4,
    }),
    ('durable_40x75', {
        'name': 'DURABLE BADGEMAKER® 40 x 75 mm (1453-02)',
        'cols': 2,
        'rows': 6,
        'margins': [28.5 * mm, 30 * mm, 28.5 * mm, 30 * mm],
        'offsets': [75 * mm, 40 * mm],
        'pagesize': pagesizes.A4,
    }),
    ('durable_60x90', {
        'name': 'DURABLE BADGEMAKER® 60 x 90 mm (1456-02)',
        'cols': 2,
        'rows': 4,
        'margins': [28.5 * mm, 15 * mm, 28.5 * mm, 15 * mm],
        'offsets': [90 * mm, 60 * mm],
        'pagesize': pagesizes.A4,
    }),
    ('durable_fix_40x75', {
        'name': 'DURABLE BADGEFIX® 40 x 75 mm (8334-02)',
        'cols': 2,
        'rows': 6,
        'margins': [28.5 * mm, 30 * mm, 28.5 * mm, 30 * mm],
        'offsets': [93 * mm, 60 * mm],
        'pagesize': pagesizes.A4,
    }),
    ('herma_50x80', {
        'name': 'HERMA 50 x 80 mm (4412)',
        'cols': 2,
        'rows': 5,
        'margins': [13.5 * mm, 17.5 * mm, 13.5 * mm, 17.5 * mm],
        'offsets': [95 * mm, 55 * mm],
        'pagesize': pagesizes.A4,
    }),
])


def render_pdf(event, positions, opt):
    from PyPDF2 import PdfFileReader, PdfFileWriter
    Renderer._register_fonts()

    renderermap = {
        bi.item_id: _renderer(event, bi.layout)
        for bi in BadgeItem.objects.select_related('layout').filter(item__event=event)
    }
    try:
        default_renderer = _renderer(event, event.badge_layouts.get(default=True))
    except BadgeLayout.DoesNotExist:
        default_renderer = None
    output_pdf_writer = PdfFileWriter()

    any = False
    npp = opt['cols'] * opt['rows']

    def render_page(positions):
        buffer = BytesIO()
        p = canvas.Canvas(buffer, pagesize=pagesizes.A4)
        for i, (op, r) in enumerate(positions):
            offsetx = opt['margins'][3] + (i % opt['cols']) * opt['offsets'][0]
            offsety = opt['margins'][2] + (opt['rows'] - 1 - i // opt['cols']) * opt['offsets'][1]
            p.translate(offsetx, offsety)
            with language(op.order.locale, op.order.event.settings.region):
                r.draw_page(p, op.order, op, show_page=False)
            p.translate(-offsetx, -offsety)

        if opt['pagesize']:
            p.setPageSize(opt['pagesize'])
        p.showPage()
        p.save()
        buffer.seek(0)
        canvas_pdf_reader = PdfFileReader(buffer)
        empty_pdf_page = output_pdf_writer.addBlankPage(
            width=opt['pagesize'][0] if opt['pagesize'] else positions[0][1].bg_pdf.getPage(0).mediaBox[2],
            height=opt['pagesize'][1] if opt['pagesize'] else positions[0][1].bg_pdf.getPage(0).mediaBox[3],
        )
        for i, (op, r) in enumerate(positions):
            bg_page = copy.copy(r.bg_pdf.getPage(0))
            offsetx = opt['margins'][3] + (i % opt['cols']) * opt['offsets'][0]
            offsety = opt['margins'][2] + (opt['rows'] - 1 - i // opt['cols']) * opt['offsets'][1]
            empty_pdf_page.mergeTranslatedPage(
                bg_page,
                tx=offsetx,
                ty=offsety
            )
        empty_pdf_page.mergePage(canvas_pdf_reader.getPage(0))

    pagebuffer = []
    outbuffer = BytesIO()
    for op in positions:
        r = renderermap.get(op.item_id, default_renderer)
        if not r:
            continue
        any = True
        pagebuffer.append((op, r))
        if len(pagebuffer) == npp:
            render_page(pagebuffer)
            pagebuffer.clear()

    if pagebuffer:
        render_page(pagebuffer)

    output_pdf_writer.addMetadata({
        '/Title': 'Badges',
        '/Creator': 'pretix',
    })
    output_pdf_writer.write(outbuffer)
    outbuffer.seek(0)
    if not any:
        raise OrderError(_("None of the selected products is configured to print badges."))
    return outbuffer


class BadgeExporter(BaseExporter):
    identifier = "badges"
    verbose_name = _("Attendee badges")

    @property
    def export_form_fields(self):
        name_scheme = PERSON_NAME_SCHEMES[self.event.settings.name_scheme]
        d = OrderedDict(
            [
                ('items',
                 forms.ModelMultipleChoiceField(
                     queryset=self.event.items.annotate(
                         no_badging=Exists(BadgeItem.objects.filter(item=OuterRef('pk'), layout__isnull=True))
                     ).exclude(no_badging=True),
                     label=_('Limit to products'),
                     widget=forms.CheckboxSelectMultiple(
                         attrs={'class': 'scrolling-multiple-choice'}
                     ),
                     initial=self.event.items.filter(admission=True)
                 )),
                ('include_pending',
                 forms.BooleanField(
                     label=_('Include pending orders'),
                     required=False
                 )),
                ('include_addons',
                 forms.BooleanField(
                     label=_('Include add-on or bundled positions'),
                     required=False
                 )),
                ('rendering',
                 forms.ChoiceField(
                     label=_('Rendering option'),
                     choices=[
                         (k, r['name']) for k, r in OPTIONS.items()
                     ],
                     required=True,
                     help_text=_('This option allows you to align multiple badges on one page, for example if you '
                                 'want to print to a sheet of stickers with a regular office printer. Please note '
                                 'that your individual badge layouts must already be in the correct size.')
                 )),
                ('order_by',
                 forms.ChoiceField(
                     label=_('Sort by'),
                     choices=[
                         ('name', _('Attendee name')),
                         ('code', _('Order code')),
                     ] + ([
                         ('name:{}'.format(k), _('Attendee name: {part}').format(part=label))
                         for k, label, w in name_scheme['fields']
                     ] if settings.JSON_FIELD_AVAILABLE and len(name_scheme['fields']) > 1 else []),
                 )),
            ]
        )
        return d

    def render(self, form_data: dict) -> Tuple[str, str, str]:
        qs = OrderPosition.objects.filter(
            order__event=self.event, item_id__in=form_data['items']
        ).prefetch_related(
            'answers', 'answers__question'
        ).select_related('order', 'item', 'variation', 'addon_to')

        if not form_data.get('include_addons'):
            qs = qs.filter(addon_to__isnull=True)

        if form_data.get('include_pending'):
            qs = qs.filter(order__status__in=[Order.STATUS_PAID, Order.STATUS_PENDING])
        else:
            qs = qs.filter(order__status__in=[Order.STATUS_PAID])

        if form_data.get('order_by') == 'name':
            qs = qs.order_by('attendee_name_cached', 'order__code')
        elif form_data.get('order_by') == 'code':
            qs = qs.order_by('order__code')
        elif form_data.get('order_by', '').startswith('name:'):
            part = form_data['order_by'][5:]
            qs = qs.annotate(
                resolved_name=Coalesce('attendee_name_parts', 'addon_to__attendee_name_parts',
                                       'order__invoice_address__name_parts')
            ).annotate(
                resolved_name_part=JSONExtract('resolved_name', part)
            ).order_by(
                'resolved_name_part'
            )

        outbuffer = render_pdf(self.event, qs, OPTIONS[form_data.get('rendering', 'one')])
        return 'badges.pdf', 'application/pdf', outbuffer.read()