"""Daily/weekly digest email rendering.
Pure prose → HTML/text rendering. SMTP transport stays in
``email_service.send_email``; this module only assembles the message
body, subject, and a text-only fallback for clients without HTML
rendering.
Split from email_service.py during the Tier 2 cleanup pass — the
SMTP/OTP/welcome surface and the digest renderer changed at very
different cadences and made the file noisy to navigate.
"""
from __future__ import annotations
import html as _html_lib
import re as _re
from app import branding
_DIGEST_HTML_TEMPLATE = """\
{brand} — {label}
|
▰ {brand_upper} · {label_upper}
{content_html}
|
"""
def _strip_html_to_text(html_body: str) -> str:
"""Best-effort HTML → plain text for the multipart fallback. We don't
need perfection — just readable prose for clients that won't render
HTML."""
text = _re.sub(r"(?i)<(/(p|h[1-6]|li|ul|ol)|br\s*/?)>", "\n", html_body)
text = _re.sub(r"<[^>]+>", "", text)
text = _html_lib.unescape(text)
text = _re.sub(r"\n{3,}", "\n\n", text)
return text.strip()
def render_digest_email(
*,
kind: str,
date_str: str,
content_html: str,
unsubscribe_url: str,
settings_url: str,
) -> tuple[str, str, str]:
"""Returns (subject, text_body, html_body) for a digest email.
`kind` is "daily" or "weekly". Anything else raises ValueError."""
if kind == "daily":
label = "Daily"
subject = f"{branding.BRAND_NAME} · Daily — {date_str}"
elif kind == "weekly":
label = "Weekly recap"
subject = f"{branding.BRAND_NAME} · Weekly recap — {date_str}"
else:
raise ValueError(f"unknown digest kind: {kind!r}")
html_body = _DIGEST_HTML_TEMPLATE.format(
brand=branding.BRAND_NAME,
brand_upper=branding.BRAND_NAME.upper(),
label=label,
label_upper=label.upper(),
FONT_MONO=branding.FONT_MONO,
content_html=content_html,
unsubscribe_url=unsubscribe_url,
settings_url=settings_url,
**{f"L_{k.replace('-', '_')}": v for k, v in branding.LIGHT.items()},
**{f"D_{k.replace('-', '_')}": v for k, v in branding.DARK.items()},
)
text_lines = [
f"{branding.BRAND_NAME} — {label}",
date_str,
"",
_strip_html_to_text(content_html),
"",
f"Unsubscribe: {unsubscribe_url}",
f"Manage preferences: {settings_url}",
]
text_body = "\n".join(text_lines)
return subject, text_body, html_body