from django import template
from django.utils.safestring import mark_safe
from urllib.request import quote as urlencode
register = template.Library()

@register.simple_tag
def mailurl(*, subject=None, body=None, to=[], cc=[], bcc=[]):
	"""Tag na vytváření správně zakódované mailto: adresy

	Ref: RFC 6068, <https://en.wikipedia.org/wiki/Mailto>"""
	if isinstance(to, str):
		to = [to]
	if isinstance(cc, str):
		cc = [cc]
	if isinstance(bcc, str):
		bcc = [bcc]
	assert isinstance(to, list)
	assert isinstance(cc, list)
	assert isinstance(bcc, list)
	# FIXME: adresa není správně zakódovaná, rozbije se to na adresách s divnými znaky
	parts = [
		f'mailto:{str.join(",", to)}',
		]
	if len(to) + len(cc) + len(bcc) < 1:
		raise ValueError('Cannot mail to empty set of people')

	if subject:
		parts.append(f'subject={urlencode(subject)}')
	if body:
		parts.append(f'body={urlencode(body)}')
	if len(cc) > 0:
		parts.append(f'cc={str.join(",", cc)}')
	if len(bcc) > 0:
		parts.append(f'bcc={str.join(",", bcc)}')
	
	if len(parts) > 1:
		url = parts[0] + '?' + str.join('&', parts[1:])
	else:
		url = parts[0]
	return url

@register.simple_tag
def maillink(text, subject=None, body=None, to=[], cc=[], bcc=[], attrs=None):
	url = mailurl(subject=subject, body=body, to=to, cc=cc, bcc=bcc)
	if not attrs: attrs = ''
	mezera = ' '*bool(attrs)
	full_link = f'<a href="{url}"{mezera}{attrs}>{text}</a>'
	return mark_safe(full_link)