import asyncio
from collections import deque
import logging
import logging.handlers
import os
import random
import sys
import time
import uuid
from datetime import datetime
from pathlib import Path

import resend
from fastapi import FastAPI, HTTPException, Request
from fastapi.middleware.cors import CORSMiddleware
from pydantic import BaseModel, EmailStr


# ── Logging ──────────────────────────────────────────────────────────────────

def _setup_logging() -> logging.Logger:
    log_dir = Path(os.environ.get("LOG_DIR", "logs"))
    log_dir.mkdir(parents=True, exist_ok=True)
    log_file = log_dir / "mail-api.log"

    fmt = logging.Formatter(
        "%(asctime)s %(levelname)-8s %(name)s: %(message)s",
        datefmt="%d/%m/%Y %H:%M:%S %Z",
    )

    root = logging.getLogger()
    root.setLevel(logging.DEBUG)
    for handler in list(root.handlers):
        root.removeHandler(handler)

    console = logging.StreamHandler(sys.stdout)
    console.setLevel(logging.INFO)
    console.setFormatter(fmt)
    root.addHandler(console)

    rotating = logging.handlers.RotatingFileHandler(
        log_file, maxBytes=2_000_000, backupCount=5, encoding="utf-8"
    )
    rotating.setLevel(logging.DEBUG)
    rotating.setFormatter(fmt)
    root.addHandler(rotating)

    log = logging.getLogger("mail-api")
    log.info("Logging initialised → console=INFO, file=%s (DEBUG, rotating)", log_file)
    return log


logger = _setup_logging()


# ── Configuration ────────────────────────────────────────────────────────────

REQUIRED_ENV = {
    "RESEND_API_KEY": "API key from https://resend.com/api-keys",
    "OWNER_EMAIL": "Email address that receives new lead notifications",
}


def _load_config() -> dict:
    missing = [(name, hint) for name, hint in REQUIRED_ENV.items() if not os.environ.get(name)]
    if missing:
        lines = [
            "",
            "Mail API cannot start — required environment variables are not set:",
            "",
        ]
        for name, hint in missing:
            lines.append(f"  • {name}  ({hint})")
        lines += [
            "",
            "Set them in your shell and try again. For example, in PowerShell:",
            "",
        ]
        for name, _ in missing:
            lines.append(f'  $env:{name} = "..."')
        lines.append("")
        message = "\n".join(lines)
        logger.critical("Startup aborted: missing env vars: %s", [n for n, _ in missing])
        print(message, file=sys.stderr)
        sys.exit(1)

    return {
        "resend_api_key": os.environ["RESEND_API_KEY"],
        "owner_email": os.environ["OWNER_EMAIL"],
        "from_email": os.environ.get("FROM_EMAIL", "GoodWalk <bookings@goodwalk.co.nz>"),
        "reply_to": os.environ.get("REPLY_TO", "aless@goodwalk.co.nz"),
        "owner_bcc": os.environ.get("OWNER_BCC", "example@example.com").strip(),
        "client_bcc": os.environ.get("CLIENT_BCC", "").strip(),
        "enable_general_enquiries": os.environ.get("ENABLE_GENERAL_ENQUIRIES", "false").strip().lower() in {"1", "true", "yes", "on", "enabled"},
        "max_attempts": max(1, int(os.environ.get("MAIL_MAX_ATTEMPTS", "3"))),
        "form_min_seconds": max(1, int(os.environ.get("FORM_MIN_SECONDS", "4"))),
        "form_max_seconds": max(60, int(os.environ.get("FORM_MAX_SECONDS", "7200"))),
        "rate_limit_window_seconds": max(60, int(os.environ.get("RATE_LIMIT_WINDOW_SECONDS", "900"))),
        "rate_limit_max_per_ip": max(1, int(os.environ.get("RATE_LIMIT_MAX_PER_IP", "5"))),
        "rate_limit_max_per_email": max(1, int(os.environ.get("RATE_LIMIT_MAX_PER_EMAIL", "3"))),
        "rate_limit_min_interval_seconds": max(1, int(os.environ.get("RATE_LIMIT_MIN_INTERVAL_SECONDS", "20"))),
    }


_config = _load_config()
APP_VERSION = os.environ.get("APP_VERSION", "unknown")
resend.api_key = _config["resend_api_key"]
OWNER_EMAIL = _config["owner_email"]
OWNER_BCC = _config["owner_bcc"]
CLIENT_BCC = _config["client_bcc"]
FROM_EMAIL = _config["from_email"]
REPLY_TO = _config["reply_to"]
ENABLE_GENERAL_ENQUIRIES = _config["enable_general_enquiries"]
MAX_SEND_ATTEMPTS = _config["max_attempts"]
FORM_MIN_SECONDS = _config["form_min_seconds"]
FORM_MAX_SECONDS = _config["form_max_seconds"]
RATE_LIMIT_WINDOW_SECONDS = _config["rate_limit_window_seconds"]
RATE_LIMIT_MAX_PER_IP = _config["rate_limit_max_per_ip"]
RATE_LIMIT_MAX_PER_EMAIL = _config["rate_limit_max_per_email"]
RATE_LIMIT_MIN_INTERVAL_SECONDS = _config["rate_limit_min_interval_seconds"]

LOGO_URL = "https://www.goodwalk.co.nz/images/goodwalk-auckland-dog-walking-logo.png"

logger.info(
    "Mail API config: version=%r timezone=%r from=%r reply_to=%r owner=%r owner_bcc=%r client_bcc=%r general_enquiries=%r max_attempts=%d form_min=%ss form_max=%ss rate_window=%ss per_ip=%d per_email=%d min_interval=%ss",
    APP_VERSION,
    os.environ.get("TZ", "system-default"),
    FROM_EMAIL,
    REPLY_TO,
    OWNER_EMAIL,
    OWNER_BCC,
    CLIENT_BCC,
    ENABLE_GENERAL_ENQUIRIES,
    MAX_SEND_ATTEMPTS,
    FORM_MIN_SECONDS,
    FORM_MAX_SECONDS,
    RATE_LIMIT_WINDOW_SECONDS,
    RATE_LIMIT_MAX_PER_IP,
    RATE_LIMIT_MAX_PER_EMAIL,
    RATE_LIMIT_MIN_INTERVAL_SECONDS,
)

app = FastAPI(title="GoodWalk Mail API")

app.add_middleware(
    CORSMiddleware,
    allow_origins=["*"],
    allow_methods=["POST", "GET"],
    allow_headers=["*"],
)


@app.middleware("http")
async def _request_logging_middleware(request: Request, call_next):
    request_id = uuid.uuid4().hex[:8]
    request.state.request_id = request_id
    started = time.monotonic()
    try:
        response = await call_next(request)
    except Exception:
        elapsed_ms = (time.monotonic() - started) * 1000
        logger.exception(
            "[%s] %s %s crashed after %.0fms",
            request_id, request.method, request.url.path, elapsed_ms,
        )
        raise
    elapsed_ms = (time.monotonic() - started) * 1000
    logger.info(
        "[%s] %s %s → %d (%.0fms)",
        request_id, request.method, request.url.path, response.status_code, elapsed_ms,
    )
    response.headers["X-Request-ID"] = request_id
    return response


class BookingSubmission(BaseModel):
    enquiryType: str = "booking"
    fullName: str
    email: EmailStr
    phone: str
    petName: str = ""
    location: str = ""
    message: str = ""
    services: list[str] = []
    website: str = ""
    formStartedAt: int | None = None
    referrer: str = ""
    page: str = ""


# ── Helpers ──────────────────────────────────────────────────────────────────

def _get_ip(request: Request) -> str:
    forwarded = request.headers.get("x-forwarded-for")
    if forwarded:
        return forwarded.split(",")[0].strip()
    return request.client.host if request.client else "unknown"


_submit_attempts_by_ip: dict[str, deque[float]] = {}
_submit_attempts_by_email: dict[str, deque[float]] = {}
_submit_rate_limit_lock = asyncio.Lock()


def _trimmed(value: str) -> str:
    return value.strip()


def _prune_attempts(attempts: deque[float], now: float, window_seconds: int) -> None:
    while attempts and now - attempts[0] > window_seconds:
        attempts.popleft()


def _seconds_until_allowed(last_attempt_at: float, now: float, min_interval_seconds: int) -> int:
    retry_after = max(1, int(min_interval_seconds - (now - last_attempt_at)))
    return retry_after


async def _enforce_submit_rate_limits(request_id: str, ip: str, email: str) -> None:
    now = time.monotonic()
    normalized_email = email.strip().lower()

    async with _submit_rate_limit_lock:
        ip_attempts = _submit_attempts_by_ip.setdefault(ip, deque())
        email_attempts = _submit_attempts_by_email.setdefault(normalized_email, deque())

        _prune_attempts(ip_attempts, now, RATE_LIMIT_WINDOW_SECONDS)
        _prune_attempts(email_attempts, now, RATE_LIMIT_WINDOW_SECONDS)

        if ip_attempts and now - ip_attempts[-1] < RATE_LIMIT_MIN_INTERVAL_SECONDS:
            retry_after = _seconds_until_allowed(ip_attempts[-1], now, RATE_LIMIT_MIN_INTERVAL_SECONDS)
            logger.warning(
                "[%s] rate limited: ip=%s submitted again after %.1fs (minimum %ss)",
                request_id,
                ip,
                now - ip_attempts[-1],
                RATE_LIMIT_MIN_INTERVAL_SECONDS,
            )
            raise HTTPException(
                status_code=429,
                detail=f"Please wait about {retry_after} seconds before trying again.",
            )

        if len(ip_attempts) >= RATE_LIMIT_MAX_PER_IP:
            logger.warning(
                "[%s] rate limited: ip=%s exceeded %d submissions in %ss",
                request_id,
                ip,
                RATE_LIMIT_MAX_PER_IP,
                RATE_LIMIT_WINDOW_SECONDS,
            )
            raise HTTPException(
                status_code=429,
                detail="Too many enquiries from this connection. Please try again a little later.",
            )

        if len(email_attempts) >= RATE_LIMIT_MAX_PER_EMAIL:
            logger.warning(
                "[%s] rate limited: email=%s exceeded %d submissions in %ss",
                request_id,
                normalized_email,
                RATE_LIMIT_MAX_PER_EMAIL,
                RATE_LIMIT_WINDOW_SECONDS,
            )
            raise HTTPException(
                status_code=429,
                detail="That email address has reached the enquiry limit for now. Please try again later.",
            )

        ip_attempts.append(now)
        email_attempts.append(now)


def _enforce_form_timing(request_id: str, data: BookingSubmission) -> None:
    if data.formStartedAt is None or data.formStartedAt <= 0:
        logger.warning("[%s] rejected: missing or invalid formStartedAt", request_id)
        raise HTTPException(
            status_code=400,
            detail="Please refresh the page and try again.",
        )

    elapsed_seconds = (time.time() * 1000 - data.formStartedAt) / 1000

    if elapsed_seconds < FORM_MIN_SECONDS:
        logger.warning(
            "[%s] rejected: form submitted too quickly (%.2fs < %ss)",
            request_id,
            elapsed_seconds,
            FORM_MIN_SECONDS,
        )
        raise HTTPException(
            status_code=400,
            detail="Please take a moment to fill in the form before sending it.",
        )

    if elapsed_seconds > FORM_MAX_SECONDS:
        logger.warning(
            "[%s] rejected: stale form submission (%.0fs > %ss)",
            request_id,
            elapsed_seconds,
            FORM_MAX_SECONDS,
        )
        raise HTTPException(
            status_code=400,
            detail="This form has been open for too long. Please refresh the page and try again.",
        )


def _is_honeypot_triggered(data: BookingSubmission) -> bool:
    return bool(_trimmed(data.website))


def _is_general_enquiry(data: BookingSubmission) -> bool:
    return _trimmed(data.enquiryType).lower() == "general"


def _enquiry_type_label(data: BookingSubmission) -> str:
    return "General enquiry" if _is_general_enquiry(data) else "Booking enquiry"


def _validate_submission(request_id: str, data: BookingSubmission) -> None:
    enquiry_type = _trimmed(data.enquiryType).lower()

    if enquiry_type not in {"booking", "general"}:
        logger.warning("[%s] rejected: invalid enquiryType=%r", request_id, data.enquiryType)
        raise HTTPException(
            status_code=400,
            detail="Please choose a valid enquiry type and try again.",
        )

    if not _trimmed(data.fullName):
        logger.warning("[%s] rejected: missing full name", request_id)
        raise HTTPException(
            status_code=400,
            detail="Please enter your full name.",
        )

    if not _trimmed(data.phone):
        logger.warning("[%s] rejected: missing phone number", request_id)
        raise HTTPException(
            status_code=400,
            detail="Please enter your contact number.",
        )

    if _is_general_enquiry(data):
        if not ENABLE_GENERAL_ENQUIRIES:
            logger.warning("[%s] rejected: general enquiries are disabled", request_id)
            raise HTTPException(
                status_code=403,
                detail="General enquiries are currently unavailable through this form.",
            )
        if not _trimmed(data.message):
            logger.warning("[%s] rejected: missing general enquiry message", request_id)
            raise HTTPException(
                status_code=400,
                detail="Please tell us how we can help.",
            )
        return

    if not _trimmed(data.petName):
        logger.warning("[%s] rejected: missing pet name", request_id)
        raise HTTPException(
            status_code=400,
            detail="Please enter your dog's name.",
        )

    if not _trimmed(data.location):
        logger.warning("[%s] rejected: missing location", request_id)
        raise HTTPException(
            status_code=400,
            detail="Please enter your location.",
        )


def _normalize_submission(data: BookingSubmission) -> None:
    data.enquiryType = "general" if _is_general_enquiry(data) else "booking"
    data.fullName = _trimmed(data.fullName)
    data.phone = _trimmed(data.phone)
    data.petName = _trimmed(data.petName)
    data.location = _trimmed(data.location)
    data.message = _trimmed(data.message)
    data.referrer = _trimmed(data.referrer)
    data.page = _trimmed(data.page)
    data.services = [_trimmed(service) for service in data.services if _trimmed(service)]

    if _is_general_enquiry(data):
        data.petName = ""
        data.location = ""
        data.services = []


def _parse_ua(ua: str) -> str:
    if not ua:
        return "Unknown"
    browsers = [("Edg/", "Edge"), ("OPR/", "Opera"), ("Chrome/", "Chrome"),
                ("Firefox/", "Firefox"), ("Safari/", "Safari")]
    systems = [("Windows NT 10", "Windows 10/11"), ("Windows NT 6", "Windows 8"),
               ("Mac OS X", "macOS"), ("iPhone", "iPhone"), ("iPad", "iPad"),
               ("Android", "Android"), ("Linux", "Linux")]
    browser = next((n for p, n in browsers if p in ua), "Unknown browser")
    system = next((n for p, n in systems if p in ua), "Unknown OS")
    return f"{browser} on {system}"


def _detail_row(label: str, value: str) -> str:
    if not value:
        return ""
    return f"""
    <tr>
      <td style="padding:8px 0;color:#888;font-size:13px;white-space:nowrap;
                 font-family:-apple-system,BlinkMacSystemFont,'Segoe UI',sans-serif;
                 vertical-align:top;width:130px;">{label}</td>
      <td style="padding:8px 0 8px 16px;color:#213021;font-size:14px;font-weight:500;
                 font-family:-apple-system,BlinkMacSystemFont,'Segoe UI',sans-serif;
                 vertical-align:top;">{value}</td>
    </tr>"""


def _meta_row(label: str, value: str) -> str:
    if not value:
        return ""
    return f"""
    <tr>
      <td style="padding:5px 0;color:#aaa;font-size:12px;white-space:nowrap;
                 font-family:-apple-system,BlinkMacSystemFont,'Segoe UI',sans-serif;
                 vertical-align:top;width:100px;">{label}</td>
      <td style="padding:5px 0 5px 16px;color:#666;font-size:12px;
                 font-family:-apple-system,BlinkMacSystemFont,'Segoe UI',sans-serif;
                 vertical-align:top;word-break:break-all;">{value}</td>
    </tr>"""


# ── Email templates ──────────────────────────────────────────────────────────

def _logo_header(badge_html: str = "", subtitle: str = "") -> str:
    badge = f'<div style="margin-top:20px;">{badge_html}</div>' if badge_html else ""
    sub = f"""<div style="font-family:-apple-system,BlinkMacSystemFont,'Segoe UI',sans-serif;
                          font-size:13px;color:#7aaa7a;letter-spacing:0.04em;margin-top:8px;">
                {subtitle}</div>""" if subtitle else ""
    return f"""
        <tr>
          <td style="background:#213021;padding:36px 48px 32px;text-align:center;">
            <img src="{LOGO_URL}" width="161" height="32" alt="GoodWalk"
                 style="display:inline-block;max-width:161px;height:auto;border:0;">
            {sub}
            {badge}
          </td>
        </tr>"""


def client_email(data: BookingSubmission) -> str:
    is_general = _is_general_enquiry(data)
    services_text = ", ".join(data.services) if data.services else "Not specified"
    enquiry_summary_rows = [
        _detail_row("Your name", data.fullName),
        _detail_row("Email", str(data.email)),
        _detail_row("Phone", data.phone),
        _detail_row("Type", _enquiry_type_label(data)),
    ]

    if is_general:
        if data.message:
            enquiry_summary_rows.append(_detail_row("Message", data.message))
        intro_html = (
            "We&rsquo;ve received your message and we will be in touch shortly."
        )
        next_steps_html = (
            "We will review your message and reply within 1 business day."
        )
        logo_subtitle = "General enquiries and dog walking support"
    else:
        enquiry_summary_rows.extend(
            [
                _detail_row("Dog&rsquo;s name", data.petName),
                _detail_row("Location", data.location),
                _detail_row("Services", services_text),
            ]
        )
        if data.message:
            enquiry_summary_rows.append(_detail_row("About the dog", data.message))
        intro_html = (
            "We&rsquo;ve received your enquiry and we will be in touch shortly to arrange "
            "a <strong style=\"color:#213021;\">Meet &amp; Greet</strong> with you and "
            f"{data.petName}."
        )
        next_steps_html = (
            "We will review your details and reach out within 1 business day "
            "to schedule a free Meet &amp; Greet. No commitment required &mdash; just a "
            f"chance for {data.petName} to make a new best friend."
        )
        logo_subtitle = "Professional dog walking services"

    return f"""<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width,initial-scale=1">
  <title>We received your enquiry</title>
</head>
<body style="margin:0;padding:0;background:#f2f2f0;">

  <table width="100%" cellpadding="0" cellspacing="0" role="presentation"
         style="background:#f2f2f0;padding:40px 16px;">
    <tr><td align="center">

      <table width="600" cellpadding="0" cellspacing="0" role="presentation"
             style="max-width:600px;width:100%;border-radius:16px;overflow:hidden;
                    box-shadow:0 4px 24px rgba(0,0,0,0.08);">

        {_logo_header(subtitle=logo_subtitle)}

        <!-- Body -->
        <tr>
          <td style="background:#ffffff;padding:48px 48px 40px;">

            <h1 style="margin:0 0 8px;font-family:-apple-system,BlinkMacSystemFont,'Segoe UI',sans-serif;
                       font-size:26px;font-weight:700;color:#213021;line-height:1.2;">
              Thanks, {data.fullName.split()[0]}! &#x1F43E;
            </h1>
            <p style="margin:0 0 32px;font-family:-apple-system,BlinkMacSystemFont,'Segoe UI',sans-serif;
                      font-size:16px;color:#555;line-height:1.65;">
              {intro_html}
            </p>

            <!-- Details card -->
            <table width="100%" cellpadding="0" cellspacing="0" role="presentation"
                   style="background:#f8f7f4;border-radius:12px;margin-bottom:36px;">
              <tr>
                <td style="padding:28px 32px;">
                  <div style="font-family:-apple-system,BlinkMacSystemFont,'Segoe UI',sans-serif;
                              font-size:11px;font-weight:700;letter-spacing:0.1em;
                              color:#888;text-transform:uppercase;margin-bottom:20px;">
                    Your enquiry summary
                  </div>
                  <table width="100%" cellpadding="0" cellspacing="0" role="presentation">
                    {"".join(enquiry_summary_rows)}
                  </table>
                </td>
              </tr>
            </table>

            <!-- What's next -->
            <table width="100%" cellpadding="0" cellspacing="0" role="presentation"
                   style="border-left:3px solid #FFD100;margin-bottom:36px;">
              <tr>
                <td style="padding:4px 0 4px 20px;">
                  <div style="font-family:-apple-system,BlinkMacSystemFont,'Segoe UI',sans-serif;
                              font-size:13px;font-weight:700;color:#213021;margin-bottom:6px;">
                    What happens next?
                  </div>
                  <div style="font-family:-apple-system,BlinkMacSystemFont,'Segoe UI',sans-serif;
                              font-size:14px;color:#666;line-height:1.6;">
                    {next_steps_html}
                  </div>
                </td>
              </tr>
            </table>

            <p style="margin:0;font-family:-apple-system,BlinkMacSystemFont,'Segoe UI',sans-serif;
                      font-size:14px;color:#888;line-height:1.6;">
              Questions? Just reply to this email or reach us at 022 642 1011.
            </p>

          </td>
        </tr>

        <!-- Footer -->
        <tr>
          <td style="background:#213021;padding:24px 48px;text-align:center;">
            <div style="font-family:-apple-system,BlinkMacSystemFont,'Segoe UI',sans-serif;
                        font-size:12px;color:#5a8a5a;line-height:1.6;">
              GoodWalk &middot; Auckland, New Zealand<br>
              <a href="https://www.goodwalk.co.nz" style="color:#7aaa7a;text-decoration:none;">
                goodwalk.co.nz
              </a>
            </div>
          </td>
        </tr>

      </table>
    </td></tr>
  </table>

</body>
</html>"""


def owner_email(data: BookingSubmission, ip: str, browser: str) -> str:
    is_general = _is_general_enquiry(data)
    services_text = ", ".join(data.services) if data.services else "—"
    now = datetime.now()
    submitted_at = now.strftime("%d %b %Y at %I:%M %p").lstrip("0")
    first_name = data.fullName.split()[0] if data.fullName.strip() else "them"
    email_title = "New GoodWalk Enquiry" if is_general else "New GoodWalk Lead"

    message_label = "Message" if is_general else "About the dog"
    message_block = f"""
    <tr>
      <td colspan="2" style="padding:16px 0 0;">
        <div style="font-family:-apple-system,BlinkMacSystemFont,'Segoe UI',sans-serif;
                    font-size:11px;font-weight:700;letter-spacing:0.08em;color:#888;
                    text-transform:uppercase;margin-bottom:8px;">{message_label}</div>
        <div style="font-family:-apple-system,BlinkMacSystemFont,'Segoe UI',sans-serif;
                    font-size:14px;color:#444;line-height:1.6;background:#f0efe9;
                    border-radius:8px;padding:14px 16px;">{data.message}</div>
      </td>
    </tr>""" if data.message else ""

    badge = """<div style="display:inline-block;background:#FFD100;border-radius:100px;
                            padding:10px 28px;">
                 <span style="font-family:-apple-system,BlinkMacSystemFont,'Segoe UI',sans-serif;
                              font-size:18px;font-weight:700;color:#213021;">
                   &#x1F4E9;&nbsp; New enquiry!
                 </span>
               </div>
               <div style="font-family:-apple-system,BlinkMacSystemFont,'Segoe UI',sans-serif;
                           font-size:12px;color:#5a8a5a;margin-top:12px;">
                 Submitted {submitted_at}
               </div>""".format(submitted_at=submitted_at)

    referrer_row = _meta_row("Came from", data.referrer) if data.referrer else _meta_row("Came from", "Direct / bookmark")
    page_row = _meta_row("Page", data.page) if data.page else ""
    detail_heading = "Enquiry details" if is_general else "Dog &amp; services"
    detail_rows = [_detail_row("Type", _enquiry_type_label(data))]

    if is_general:
        if data.petName:
            detail_rows.append(_detail_row("Dog", data.petName))
        if data.location:
            detail_rows.append(_detail_row("Location", data.location))
    else:
        detail_rows.extend(
            [
                _detail_row("Dog", data.petName),
                _detail_row("Location", data.location),
                _detail_row("Services", services_text),
            ]
        )

    return f"""<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width,initial-scale=1">
  <title>{email_title}</title>
</head>
<body style="margin:0;padding:0;background:#f2f2f0;">

  <table width="100%" cellpadding="0" cellspacing="0" role="presentation"
         style="background:#f2f2f0;padding:40px 16px;">
    <tr><td align="center">

      <table width="600" cellpadding="0" cellspacing="0" role="presentation"
             style="max-width:600px;width:100%;border-radius:16px;overflow:hidden;
                    box-shadow:0 4px 24px rgba(0,0,0,0.08);">

        {_logo_header(badge_html=badge)}

        <!-- Body -->
        <tr>
          <td style="background:#ffffff;padding:40px 48px 36px;">

            <!-- Quick contact -->
            <table width="100%" cellpadding="0" cellspacing="0" role="presentation"
                   style="background:#213021;border-radius:12px;margin-bottom:28px;">
              <tr>
                <td style="padding:22px 24px;">
                  <div style="font-family:-apple-system,BlinkMacSystemFont,'Segoe UI',sans-serif;
                              font-size:11px;font-weight:700;letter-spacing:0.1em;color:#7aaa7a;
                              text-transform:uppercase;margin-bottom:10px;">
                    Quick contact
                  </div>
                  <div style="font-family:-apple-system,BlinkMacSystemFont,'Segoe UI',sans-serif;
                              font-size:14px;color:#d8e6d8;line-height:1.6;margin-bottom:10px;">
                    Email {first_name} directly:
                  </div>
                  <div style="font-family:Menlo,Consolas,'SFMono-Regular',monospace;
                              font-size:20px;font-weight:700;color:#ffffff;line-height:1.4;
                              word-break:break-all;margin-bottom:12px;">
                    {data.email}
                  </div>
                  <div style="font-family:-apple-system,BlinkMacSystemFont,'Segoe UI',sans-serif;
                              font-size:12px;color:#b7cbb7;line-height:1.6;">
                    Tap and hold the address to copy on iPhone, or tap below to open a new email.
                  </div>
                </td>
              </tr>
            </table>

            <!-- Owner details -->
            <div style="font-family:-apple-system,BlinkMacSystemFont,'Segoe UI',sans-serif;
                        font-size:11px;font-weight:700;letter-spacing:0.1em;color:#888;
                        text-transform:uppercase;margin-bottom:16px;">Owner details</div>

            <table width="100%" cellpadding="0" cellspacing="0" role="presentation"
                   style="background:#f8f7f4;border-radius:12px;margin-bottom:28px;">
              <tr><td style="padding:24px 28px;">
                <table width="100%" cellpadding="0" cellspacing="0" role="presentation">
                  <tr>
                    <td style="padding:6px 0;font-size:13px;color:#888;width:80px;
                               font-family:-apple-system,BlinkMacSystemFont,'Segoe UI',sans-serif;
                               vertical-align:top;">Name</td>
                    <td style="padding:6px 0 6px 16px;font-size:15px;font-weight:600;
                               color:#213021;font-family:-apple-system,BlinkMacSystemFont,
                               'Segoe UI',sans-serif;vertical-align:top;">{data.fullName}</td>
                  </tr>
                  <tr>
                    <td style="padding:6px 0;font-size:13px;color:#888;
                               font-family:-apple-system,BlinkMacSystemFont,'Segoe UI',sans-serif;
                               vertical-align:top;">Email</td>
                    <td style="padding:6px 0 6px 16px;font-size:14px;
                               font-family:-apple-system,BlinkMacSystemFont,'Segoe UI',sans-serif;
                               vertical-align:top;">
                      <a href="mailto:{data.email}" style="color:#213021;font-weight:500;
                         text-decoration:none;">{data.email}</a>
                    </td>
                  </tr>
                  <tr>
                    <td style="padding:6px 0;font-size:13px;color:#888;
                               font-family:-apple-system,BlinkMacSystemFont,'Segoe UI',sans-serif;
                               vertical-align:top;">Phone</td>
                    <td style="padding:6px 0 6px 16px;font-size:14px;
                               font-family:-apple-system,BlinkMacSystemFont,'Segoe UI',sans-serif;
                               vertical-align:top;">
                      <a href="tel:{data.phone}" style="color:#213021;font-weight:500;
                         text-decoration:none;">{data.phone}</a>
                    </td>
                  </tr>
                </table>
              </td></tr>
            </table>

            <!-- Dog & service details -->
            <div style="font-family:-apple-system,BlinkMacSystemFont,'Segoe UI',sans-serif;
                        font-size:11px;font-weight:700;letter-spacing:0.1em;color:#888;
                        text-transform:uppercase;margin-bottom:16px;">{detail_heading}</div>

            <table width="100%" cellpadding="0" cellspacing="0" role="presentation"
                   style="background:#f8f7f4;border-radius:12px;margin-bottom:28px;">
              <tr><td style="padding:24px 28px;">
                <table width="100%" cellpadding="0" cellspacing="0" role="presentation">
                  {"".join(detail_rows)}
                  {message_block}
                </table>
              </td></tr>
            </table>

            <!-- CTA buttons -->
            <table cellpadding="0" cellspacing="0" role="presentation" style="margin-bottom:32px;">
              <tr>
                <td style="padding-right:12px;">
                  <a href="mailto:{data.email}"
                     style="display:inline-block;background:#213021;color:#FFD100;
                            font-family:-apple-system,BlinkMacSystemFont,'Segoe UI',sans-serif;
                            font-size:14px;font-weight:600;text-decoration:none;
                            border-radius:8px;padding:12px 24px;">
                    Email {first_name}
                  </a>
                </td>
                <td>
                  <a href="tel:{data.phone}"
                     style="display:inline-block;background:#f8f7f4;color:#213021;
                            font-family:-apple-system,BlinkMacSystemFont,'Segoe UI',sans-serif;
                            font-size:14px;font-weight:600;text-decoration:none;
                            border-radius:8px;padding:12px 24px;border:1px solid #e0e0d8;">
                    Call {data.phone}
                  </a>
                </td>
              </tr>
            </table>

            <!-- Session info -->
            <table width="100%" cellpadding="0" cellspacing="0" role="presentation"
                   style="border-top:1px solid #eeeee8;padding-top:20px;">
              <tr><td>
                <div style="font-family:-apple-system,BlinkMacSystemFont,'Segoe UI',sans-serif;
                            font-size:11px;font-weight:700;letter-spacing:0.08em;color:#ccc;
                            text-transform:uppercase;margin-bottom:12px;">Session info</div>
                <table width="100%" cellpadding="0" cellspacing="0" role="presentation">
                  {_meta_row("IP address", ip)}
                  {_meta_row("Browser", browser)}
                  {referrer_row}
                  {page_row}
                </table>
              </td></tr>
            </table>

          </td>
        </tr>

        <!-- Footer -->
        <tr>
          <td style="background:#f8f7f4;padding:18px 48px;text-align:center;
                     border-top:1px solid #e8e8e4;">
            <div style="font-family:-apple-system,BlinkMacSystemFont,'Segoe UI',sans-serif;
                        font-size:12px;color:#bbb;">
              Sent automatically by GoodWalk enquiry form
            </div>
          </td>
        </tr>

      </table>
    </td></tr>
  </table>

</body>
</html>"""


# ── Sending with retries ─────────────────────────────────────────────────────

async def _send_email(payload: dict, label: str, request_id: str) -> dict:
    last_exc: Exception | None = None

    for attempt in range(1, MAX_SEND_ATTEMPTS + 1):
        started = time.monotonic()
        try:
            result = await asyncio.to_thread(resend.Emails.send, payload)
            elapsed_ms = (time.monotonic() - started) * 1000
            email_id = result.get("id") if isinstance(result, dict) else None
            logger.info(
                "[%s] %s sent to %s (attempt %d/%d, %.0fms, id=%s)",
                request_id, label, payload.get("to"), attempt, MAX_SEND_ATTEMPTS,
                elapsed_ms, email_id or "n/a",
            )
            return result or {}
        except Exception as exc:
            last_exc = exc
            elapsed_ms = (time.monotonic() - started) * 1000
            status = getattr(exc, "status_code", None) or getattr(exc, "code", None)
            non_retryable = (
                isinstance(status, int) and 400 <= status < 500 and status != 429
            )
            logger.warning(
                "[%s] %s send failed (attempt %d/%d, %.0fms): %s: %s (status=%s)",
                request_id, label, attempt, MAX_SEND_ATTEMPTS, elapsed_ms,
                type(exc).__name__, exc, status,
                exc_info=True,
            )
            if non_retryable:
                logger.info(
                    "[%s] %s: non-retryable status %s, aborting retries",
                    request_id, label, status,
                )
                break
            if attempt == MAX_SEND_ATTEMPTS:
                break
            backoff = (2 ** (attempt - 1)) + random.uniform(0, 0.4)
            logger.info("[%s] retrying %s in %.2fs", request_id, label, backoff)
            await asyncio.sleep(backoff)

    assert last_exc is not None
    raise last_exc


# ── Routes ───────────────────────────────────────────────────────────────────

@app.get("/health")
async def health() -> dict:
    return {"status": "ok"}


@app.post("/submit")
async def submit_booking(data: BookingSubmission, request: Request):
    request_id = getattr(request.state, "request_id", uuid.uuid4().hex[:8])
    ip = _get_ip(request)
    browser = _parse_ua(request.headers.get("user-agent", ""))

    await _enforce_submit_rate_limits(request_id, ip, str(data.email))
    _enforce_form_timing(request_id, data)

    if _is_honeypot_triggered(data):
        logger.warning(
            "[%s] honeypot triggered for ip=%s email=%s page=%r",
            request_id,
            ip,
            data.email,
            data.page,
        )
        return {
            "ok": True,
            "request_id": request_id,
            "ignored": True,
        }

    _validate_submission(request_id, data)
    _normalize_submission(data)

    name_parts = data.fullName.split()
    first_name = name_parts[0] if name_parts else "there"

    logger.info(
        "[%s] /submit: type=%s email=%s ip=%s browser=%r dog=%s services=%s page=%r",
        request_id, data.enquiryType, data.email, ip, browser, data.petName, data.services, data.page,
    )
    logger.debug("[%s] full payload: %s", request_id, data.model_dump())

    failures: list[dict] = []

    client_payload = {
        "from": FROM_EMAIL,
        "to": [data.email],
        "reply_to": REPLY_TO,
        "subject": f"We received your {'general enquiry' if _is_general_enquiry(data) else 'enquiry'}, {first_name}! 🐾",
        "html": client_email(data),
    }
    if CLIENT_BCC:
        client_payload["bcc"] = [CLIENT_BCC]

    try:
        await _send_email(
            client_payload,
            label="client_email",
            request_id=request_id,
        )
    except Exception as exc:
        failures.append({
            "label": "client_email",
            "error_type": type(exc).__name__,
            "error": str(exc),
            "status": getattr(exc, "status_code", None) or getattr(exc, "code", None),
        })

    owner_payload = {
        "from": FROM_EMAIL,
        "to": [OWNER_EMAIL],
        "reply_to": data.email,
        "subject": (
            f"New GoodWalk general enquiry — {data.fullName}"
            if _is_general_enquiry(data)
            else f"New GoodWalk lead — {data.fullName} ({data.petName})"
        ),
        "html": owner_email(data, ip, browser),
    }
    if OWNER_BCC:
        owner_payload["bcc"] = [OWNER_BCC]

    try:
        await _send_email(
            owner_payload,
            label="owner_email",
            request_id=request_id,
        )
    except Exception as exc:
        failures.append({
            "label": "owner_email",
            "error_type": type(exc).__name__,
            "error": str(exc),
            "status": getattr(exc, "status_code", None) or getattr(exc, "code", None),
        })

    if len(failures) == 2:
        logger.error("[%s] both emails failed after retries: %s", request_id, failures)
        raise HTTPException(
            status_code=502,
            detail={
                "request_id": request_id,
                "message": "Both confirmation and notification emails failed to send. Please try again shortly.",
                "failures": failures,
            },
        )

    if failures:
        logger.warning("[%s] partial failure: %s", request_id, failures)

    return {
        "ok": True,
        "request_id": request_id,
        "partial_failures": [f["label"] for f in failures],
    }
