import asyncio
import json
import logging
import smtplib
import threading
from email.mime.base import MIMEBase
from email.mime.multipart import MIMEMultipart
from email.mime.text import MIMEText
from email import encoders
from pathlib import Path

from backend.config import charger_config, RACINE

log = logging.getLogger("photobooth.mailer")

FICHIER_SPOOL = RACINE / "data" / "email_spool.json"
_spool_lock = threading.Lock()


def envoyer_photo(destinataire: str, chemin_photo: Path) -> bool:
    """Envoie une photo par email."""
    config = charger_config()
    conf_email = config.get("email", {})
    conf_event = config.get("evenement", {})

    smtp_host = conf_email.get("smtp_host", "")
    smtp_port = conf_email.get("smtp_port", 587)
    smtp_user = conf_email.get("smtp_user", "")
    smtp_password = conf_email.get("smtp_password", "")
    expediteur = conf_email.get("expediteur", smtp_user)

    if not smtp_host or not smtp_user:
        log.error("Configuration email incomplete")
        return False

    sujet = conf_email.get("sujet", "Votre photo - {evenement}").format(
        evenement=conf_event.get("nom", "Photobooth")
    )
    message = conf_email.get("message", "Voici votre photo !").format(
        evenement=conf_event.get("nom", "Photobooth")
    )

    msg = MIMEMultipart()
    msg["From"] = expediteur
    msg["To"] = destinataire
    msg["Subject"] = sujet
    msg.attach(MIMEText(message, "plain", "utf-8"))

    # Piece jointe
    if chemin_photo.exists():
        with open(chemin_photo, "rb") as f:
            piece = MIMEBase("image", "jpeg")
            piece.set_payload(f.read())
            encoders.encode_base64(piece)
            piece.add_header(
                "Content-Disposition",
                f"attachment; filename={chemin_photo.name}"
            )
            msg.attach(piece)

    try:
        with smtplib.SMTP(smtp_host, smtp_port, timeout=10) as serveur:
            serveur.starttls()
            serveur.login(smtp_user, smtp_password)
            serveur.send_message(msg)
        log.info(f"Email envoye a {destinataire}")
        _sauvegarder_email_historique(destinataire)
        return True
    except (smtplib.SMTPException, OSError) as e:
        log.error(f"Erreur envoi email : {e}")
        return False


# --- Spool : file d'attente pour emails en echec ---

def ajouter_au_spool(destinataire: str, chemin_photo: str):
    with _spool_lock:
        spool = _charger_spool()
        spool.append({"email": destinataire, "photo": chemin_photo})
        _sauver_spool(spool)
    log.info(f"Email pour {destinataire} mis en file d'attente ({len(spool)} en attente)")


def _charger_spool() -> list:
    if not FICHIER_SPOOL.exists():
        return []
    try:
        with open(FICHIER_SPOOL, "r", encoding="utf-8") as f:
            return json.load(f)
    except (json.JSONDecodeError, OSError):
        return []


def _sauver_spool(spool: list):
    try:
        with open(FICHIER_SPOOL, "w", encoding="utf-8") as f:
            json.dump(spool, f, ensure_ascii=False)
    except OSError:
        pass


def taille_spool() -> int:
    with _spool_lock:
        return len(_charger_spool())


EMAIL_RAPPORT = "contact@copydev.fr"


def traiter_spool() -> tuple[int, list[str]]:
    """Tente d'envoyer les emails en attente. Retourne (nb envoyes, liste destinataires)."""
    with _spool_lock:
        spool = _charger_spool()
    if not spool:
        return 0, []

    envoyes = 0
    destinataires = []
    restants = []
    for entry in spool:
        chemin = Path(entry["photo"])
        if not chemin.exists():
            log.warning(f"Spool: photo introuvable {chemin}, email ignore")
            continue
        ok = envoyer_photo(entry["email"], chemin)
        if ok:
            envoyes += 1
            destinataires.append(entry["email"])
        else:
            restants.append(entry)
            break

    if envoyes > 0 or len(restants) < len(spool):
        idx = envoyes + len(restants)
        restants.extend(spool[idx:])
        with _spool_lock:
            _sauver_spool(restants)
        log.info(f"Spool: {envoyes} envoye(s), {len(restants)} en attente")

    return envoyes, destinataires


def envoyer_rapport_spool(nb_envoyes: int, destinataires: list[str], nb_echoues: int):
    """Envoie un rapport a contact@copydev.fr apres vidage du spool."""
    config = charger_config()
    conf_email = config.get("email", {})
    conf_event = config.get("evenement", {})
    nom_event = conf_event.get("nom", "Photobooth")

    smtp_host = conf_email.get("smtp_host", "")
    smtp_port = conf_email.get("smtp_port", 587)
    smtp_user = conf_email.get("smtp_user", "")
    smtp_password = conf_email.get("smtp_password", "")
    expediteur = conf_email.get("expediteur", smtp_user)

    if not smtp_host or not smtp_user:
        return

    liste = "\n".join(f"  - {d}" for d in destinataires)
    corps = f"{nb_envoyes} photo(s) envoyée(s) par email.\n\n"
    corps += f"Destinataires :\n{liste}\n"
    if nb_echoues > 0:
        corps += f"\n{nb_echoues} email(s) en échec (restent en file d'attente).\n"

    msg = MIMEMultipart()
    msg["From"] = expediteur
    msg["To"] = EMAIL_RAPPORT
    msg["Subject"] = f"[{nom_event}] {nb_envoyes} photo(s) envoyée(s)"
    msg.attach(MIMEText(corps, "plain", "utf-8"))

    try:
        with smtplib.SMTP(smtp_host, smtp_port, timeout=10) as serveur:
            serveur.starttls()
            serveur.login(smtp_user, smtp_password)
            serveur.send_message(msg)
        log.info(f"Rapport spool envoye a {EMAIL_RAPPORT}")
    except (smtplib.SMTPException, OSError) as e:
        log.error(f"Erreur envoi rapport spool : {e}")


async def tache_spool_demarrage():
    """Tente de vider le spool une seule fois au demarrage du serveur."""
    await asyncio.sleep(10)
    total = taille_spool()
    if total > 0:
        log.info(f"Spool: tentative d'envoi au demarrage ({total} en attente)")
        nb, dests = await asyncio.get_event_loop().run_in_executor(None, traiter_spool)
        if nb > 0:
            echoues = total - nb
            await asyncio.get_event_loop().run_in_executor(
                None, envoyer_rapport_spool, nb, dests, echoues
            )


FICHIER_EMAILS = RACINE / "data" / "emails_history.json"


def _event_id_actif() -> str:
    return charger_config().get("evenement", {}).get("event_id") or "_sans_evenement"


def _charger_toutes_historiques() -> dict:
    if not FICHIER_EMAILS.exists():
        return {}
    try:
        with open(FICHIER_EMAILS, "r", encoding="utf-8") as f:
            data = json.load(f)
        # Compatibilite avec l'ancien format (liste globale non cloisonnee)
        if isinstance(data, list):
            return {"_sans_evenement": data}
        return data
    except (json.JSONDecodeError, OSError):
        return {}


def _sauvegarder_email_historique(email: str):
    toutes = _charger_toutes_historiques()
    event_id = _event_id_actif()
    historique = toutes.setdefault(event_id, [])
    email_lower = email.lower().strip()
    if email_lower not in historique:
        historique.append(email_lower)
        try:
            with open(FICHIER_EMAILS, "w", encoding="utf-8") as f:
                json.dump(toutes, f, ensure_ascii=False)
        except OSError:
            pass


def charger_emails_historique() -> list:
    return _charger_toutes_historiques().get(_event_id_actif(), [])


def effacer_emails_historique():
    toutes = _charger_toutes_historiques()
    toutes.pop(_event_id_actif(), None)
    try:
        with open(FICHIER_EMAILS, "w", encoding="utf-8") as f:
            json.dump(toutes, f, ensure_ascii=False)
    except OSError:
        pass