"""Shared context for branded HTML/text emails (public site palette)."""

from __future__ import annotations

import html
import logging
import re

from django.conf import settings
from django.contrib.staticfiles.storage import staticfiles_storage

logger = logging.getLogger(__name__)

_URL_RE = re.compile(r"(https?://[^\s<]+)")
_LOGO_STATIC_PATH = "brand/exit_logo.png"


def _absolute_static_url(site_url: str, relative: str) -> str:
    """
    Build an absolute URL for a static asset.

    Prefer the hashed Manifest URL when available. Fall back to the stable
    path when the manifest is missing (dj-queue worker does not run
    collectstatic) so sending mail never crashes.
    """
    try:
        path = staticfiles_storage.url(relative)
    except ValueError:
        logger.debug(
            "staticfiles manifest miss for %s; using unhashed URL", relative
        )
        static_prefix = settings.STATIC_URL or "/static/"
        path = f"{static_prefix}{relative.lstrip('/')}"

    if path.startswith("http://") or path.startswith("https://"):
        return path
    if not path.startswith("/"):
        path = f"/{path}"
    return f"{site_url}{path}"


def _tagline_with_site_link(tagline: str, site_url: str) -> str:
    """Turn leading MKDRealtor.com (or similar) into a link to the public site."""
    raw = (tagline or "").strip()
    if not raw:
        return ""
    # Match "MKDRealtor.com" (any case) at the start, optional trailing " · rest"
    match = re.match(
        r"(?i)^(MKDRealtor\.com)(\s*[·•\-–—]\s*.*)?$",
        raw,
    )
    if not match:
        return html.escape(raw)
    label = html.escape(match.group(1))
    rest = html.escape(match.group(2) or "")
    href = html.escape(site_url, quote=True)
    return (
        f'<a href="{href}" style="color:#00626c;text-decoration:none;">{label}</a>'
        f"{rest}"
    )


def email_brand_context(**extra):
    site_url = (getattr(settings, "PUBLIC_SITE_URL", None) or "").rstrip("/")
    if not site_url:
        site_url = "https://mkdrealtor.com"

    logo_url = _absolute_static_url(site_url, _LOGO_STATIC_PATH)

    brand_name = getattr(settings, "SITE_NAME", None) or "Monica Dhillon"
    brand_legal = getattr(settings, "CREDIT_NAME", None) or brand_name
    tagline = getattr(settings, "SITE_TAGLINE", None) or ""
    host_label = site_url.replace("https://", "").replace("http://", "")

    return {
        "site_url": site_url,
        "logo_url": logo_url,
        "brand_name": brand_name,
        "brand_legal": brand_legal,
        "brand_tagline": tagline,
        "brand_tagline_html": _tagline_with_site_link(tagline, site_url),
        "host_label": host_label,
        **extra,
    }


def plain_text_to_email_html(text: str) -> str:
    """Escape plain text and turn paragraphs / URLs into simple HTML."""
    raw = (text or "").replace("\r\n", "\n").strip()
    if not raw:
        return ""

    blocks: list[str] = []
    for para in re.split(r"\n\s*\n", raw):
        lines = [html.escape(line) for line in para.split("\n")]
        joined = "<br>\n".join(lines)
        joined = _URL_RE.sub(
            r'<a href="\1" style="color:#00626c;text-decoration:underline;">\1</a>',
            joined,
        )
        blocks.append(
            f'<p style="margin:0 0 16px;color:#212121;font-size:15px;'
            f'line-height:1.6;">{joined}</p>'
        )
    return "\n".join(blocks)


_HTML_TAG_RE = re.compile(
    r"<\s*(p|div|br|span|strong|em|b|i|u|a|img|h[1-6]|ul|ol|li|font|table)\b",
    re.I,
)


def sanitize_email_html(raw: str) -> str:
    """Light cleanup for staff-authored HTML (Quill) before sending."""
    text = raw or ""
    text = re.sub(r"(?is)<script[^>]*>.*?</script>", "", text)
    text = re.sub(r"(?is)<iframe[^>]*>.*?</iframe>", "", text)
    text = re.sub(r"(?is)<object[^>]*>.*?</object>", "", text)
    text = re.sub(r"(?i)\son\w+\s*=\s*([\"']).*?\1", "", text)
    text = re.sub(r"(?i)\son\w+\s*=\s*[^\s>]+", "", text)
    text = re.sub(r"(?i)javascript:", "", text)
    return text.strip()


def campaign_body_to_email_html(body: str) -> str:
    """Render campaign body for email — HTML as-is when Quill markup, else plain."""
    raw = (body or "").strip()
    if not raw:
        return ""
    if _HTML_TAG_RE.search(raw):
        return sanitize_email_html(raw)
    return plain_text_to_email_html(raw)


def campaign_body_to_plain_text(body: str) -> str:
    """Plain-text alternative for multipart emails."""
    from django.utils.html import strip_tags

    raw = (body or "").strip()
    if not raw:
        return ""
    if _HTML_TAG_RE.search(raw):
        text = strip_tags(sanitize_email_html(raw))
        return html.unescape(re.sub(r"[ \t]+\n", "\n", text)).strip()
    return raw