"""BAN YARO — Mailing (Admin)"""

import imaplib
import os
import smtplib
import ssl
from email.mime.text import MIMEText
from email.mime.multipart import MIMEMultipart
from email.utils import formataddr, formatdate
from datetime import datetime
from typing import List, Optional

import logging

from fastapi import APIRouter, Depends, HTTPException
from pydantic import BaseModel

from auth import require_admin
from database import db

router  = APIRouter()
_log    = logging.getLogger(__name__)

_SMTP_HOST = os.getenv("SMTP_HOST", "mail.your-server.de")
_SMTP_PORT = int(os.getenv("SMTP_PORT", "587"))
_IMAP_HOST = os.getenv("IMAP_HOST", "mail.your-server.de")
_IMAP_PORT = int(os.getenv("IMAP_PORT", "993"))

_ACCOUNTS = {
    "partner": {
        "user": os.getenv("SMTP_USER", ""),
        "pass": os.getenv("SMTP_PASS", ""),
        "from": "partner@banyaro.app",
        "name": "Ban Yaro Partner",
    },
    "support": {
        "user": os.getenv("SMTP_SUPPORT_USER", "support@banyaro.de"),
        "pass": os.getenv("SMTP_SUPPORT_PASS", ""),
        "from": "support@banyaro.app",
        "name": "Ban Yaro Support",
    },
}

# Mögliche Namen für den Sent-Ordner (Hetzner/Dovecot)
_SENT_CANDIDATES = ["Sent", "Sent Messages", "Sent Items", "INBOX.Sent", "Gesendete Objekte"]


def _imap_save_sent(msg_bytes: bytes, account: str):
    acc = _ACCOUNTS.get(account) or _ACCOUNTS["partner"]
    if not acc["user"] or not acc["pass"]:
        _log.warning("IMAP: Account '%s' nicht konfiguriert, überspringe.", account)
        return
    try:
        ctx = ssl.create_default_context()
        with imaplib.IMAP4_SSL(_IMAP_HOST, _IMAP_PORT, ssl_context=ctx) as imap:
            imap.login(acc["user"], acc["pass"])
            _, raw_folders = imap.list()
            available = [f.decode(errors="replace") for f in (raw_folders or [])]
            _log.info("IMAP Ordner (%s): %s", account, available)

            # Echten Ordnernamen aus LIST-Antwort extrahieren
            # Format: '(\Flags) "." INBOX.Sent'  → letztes Token
            folder = None
            for line in available:
                name = line.rsplit('"." ', 1)[-1].strip().strip('"')
                for candidate in _SENT_CANDIDATES:
                    if candidate.lower() in name.lower():
                        folder = name
                        break
                if folder:
                    break
            if not folder:
                folder = "INBOX.Sent"
            _log.info("IMAP: speichere in Ordner '%s' (%s)", folder, account)

            typ, data = imap.append(
                folder,
                r"\Seen",
                imaplib.Time2Internaldate(datetime.now().timestamp()),
                msg_bytes,
            )
            _log.info("IMAP append: %s %s", typ, data)
    except Exception as e:
        _log.error("IMAP Sent-Speicherung fehlgeschlagen (%s): %s", account, e)


def _build_message(to: str, subject: str, body: str, account: str, html: str = None) -> MIMEMultipart:
    acc = _ACCOUNTS.get(account) or _ACCOUNTS["partner"]
    msg = MIMEMultipart("alternative")
    msg["Date"]     = formatdate(localtime=False)  # UTC explizit, Container hat keine lokale TZ
    msg["Subject"]  = subject
    msg["From"]     = formataddr((acc["name"], acc["from"]))
    msg["To"]       = to
    msg["Reply-To"] = acc["from"]
    msg.attach(MIMEText(body, "plain", "utf-8"))
    if html:
        msg.attach(MIMEText(html, "html", "utf-8"))
    return msg


_LEGAL_FOOTER = (
    "\n\n---\n"
    "Ban Yaro | René Degelmann | Ringstr. 26, D-85560 Ebersberg\n"
    "Web: https://banyaro.app | Mail: partner@banyaro.app\n\n"
    "Datenschutzhinweis: Deine Kontaktdaten stammen aus deinem öffentlichen Profil. "
    "Verarbeitung auf Basis berechtigten Interesses (Art. 6 Abs. 1 lit. f DSGVO). "
    "Datenschutzerklärung: https://banyaro.app/datenschutz\n"
    "Widerspruch/Löschung: Einfach auf diese Mail antworten."
)


def _send_smtp(to: str, subject: str, body: str, account: str = "partner", html: str = None):
    acc = _ACCOUNTS.get(account) or _ACCOUNTS["partner"]
    if not acc["user"] or not acc["pass"]:
        raise RuntimeError(f"SMTP-Account '{account}' nicht konfiguriert.")
    msg = _build_message(to, subject, body + _LEGAL_FOOTER, account, html=html)
    msg_bytes = msg.as_bytes()
    ctx = ssl.create_default_context()
    if _SMTP_PORT == 465:
        with smtplib.SMTP_SSL(_SMTP_HOST, _SMTP_PORT, context=ctx, timeout=15) as s:
            s.login(acc["user"], acc["pass"])
            s.sendmail(acc["from"], [to], msg_bytes)
    else:  # 587 oder 25 mit STARTTLS
        with smtplib.SMTP(_SMTP_HOST, _SMTP_PORT, timeout=15) as s:
            s.ehlo()
            if s.has_extn("starttls"):
                s.starttls(context=ctx)
            s.login(acc["user"], acc["pass"])
            s.sendmail(acc["from"], [to], msg_bytes)
    _imap_save_sent(msg_bytes, account)


# ------------------------------------------------------------------
# Schemas
# ------------------------------------------------------------------

class TemplateIn(BaseModel):
    key: str
    label: str
    subject: str
    body: str
    from_account: str = "partner"


class TemplateUpdate(BaseModel):
    label: str
    subject: str
    body: str
    from_account: str = "partner"


class SendRequest(BaseModel):
    to: List[str]
    subject: str
    body: str
    from_account: str = "partner"
    template_id: Optional[int] = None


# ------------------------------------------------------------------
# Templates CRUD
# ------------------------------------------------------------------

@router.get("/templates")
def list_templates(user=Depends(require_admin)):
    with db() as conn:
        rows = conn.execute(
            "SELECT id, key, label, subject, body, from_account FROM email_templates ORDER BY id"
        ).fetchall()
    return [dict(r) for r in rows]


@router.post("/templates", status_code=201)
def create_template(data: TemplateIn, user=Depends(require_admin)):
    try:
        with db() as conn:
            row = conn.execute(
                """INSERT INTO email_templates (key, label, subject, body, from_account, created_at)
                   VALUES (?, ?, ?, ?, ?, ?) RETURNING id""",
                (data.key, data.label, data.subject, data.body, data.from_account,
                 datetime.utcnow().isoformat())
            ).fetchone()
        return {"id": row["id"]}
    except Exception as e:
        raise HTTPException(400, f"Vorlage konnte nicht angelegt werden: {e}")


@router.put("/templates/{tpl_id}")
def update_template(tpl_id: int, data: TemplateUpdate, user=Depends(require_admin)):
    with db() as conn:
        conn.execute(
            """UPDATE email_templates
               SET label=?, subject=?, body=?, from_account=?, updated_at=?
               WHERE id=?""",
            (data.label, data.subject, data.body, data.from_account,
             datetime.utcnow().isoformat(), tpl_id)
        )
    return {"ok": True}


@router.delete("/templates/{tpl_id}")
def delete_template(tpl_id: int, user=Depends(require_admin)):
    with db() as conn:
        conn.execute("DELETE FROM email_templates WHERE id=?", (tpl_id,))
    return {"ok": True}


# ------------------------------------------------------------------
# Senden
# ------------------------------------------------------------------

def _plain_to_html_body(text: str) -> str:
    import html as h
    paragraphs = text.strip().split("\n\n")
    parts = []
    for p in paragraphs:
        escaped = h.escape(p).replace("\n", "<br>")
        parts.append(f'<p style="margin:0 0 14px;color:#444">{escaped}</p>')
    return "".join(parts)


@router.post("/send")
def send_mail(data: SendRequest, user=Depends(require_admin)):
    if not data.to:
        raise HTTPException(400, "Mindestens eine Empfänger-Adresse angeben.")
    if not data.subject.strip() or not data.body.strip():
        raise HTTPException(400, "Betreff und Text dürfen nicht leer sein.")

    from mailer import email_html
    html = email_html(
        _plain_to_html_body(data.body),
        footer_text=f"Ban Yaro · banyaro.app · {data.subject}",
    )

    sent, failed = [], []
    for addr in data.to:
        addr = addr.strip()
        if not addr:
            continue
        try:
            _send_smtp(addr, data.subject, data.body, data.from_account, html=html)
            sent.append(addr)
            with db() as conn:
                conn.execute(
                    """INSERT INTO outreach_log
                       (sent_by, recipient, subject, body, from_account, sent_at)
                       VALUES (?, ?, ?, ?, ?, ?)""",
                    (user["id"], addr, data.subject, data.body, data.from_account,
                     datetime.utcnow().isoformat())
                )
        except Exception as e:
            failed.append({"addr": addr, "error": str(e)})

    return {"sent": sent, "failed": failed}


# ------------------------------------------------------------------
# Support-Versand (intern, ohne Admin-Auth — für Moderatoren-Trigger)
# ------------------------------------------------------------------

def send_support_mail(to: str, subject: str, body: str):
    """Intern aufrufbar ohne HTTP-Request — z.B. aus Moderations-Logik."""
    from mailer import email_html
    html = email_html(_plain_to_html_body(body))
    _send_smtp(to, subject, body, "support", html=html)


# ------------------------------------------------------------------
# Log
# ------------------------------------------------------------------

@router.get("/log")
def outreach_log_endpoint(user=Depends(require_admin)):
    with db() as conn:
        rows = conn.execute(
            """SELECT ol.id, ol.recipient, ol.subject, ol.body, ol.sent_at,
                      ol.from_account, u.name AS sent_by_name
               FROM outreach_log ol
               JOIN users u ON u.id = ol.sent_by
               ORDER BY ol.sent_at DESC LIMIT 200"""
        ).fetchall()
    return [dict(r) for r in rows]