"""
EmailManager — Gmail cleanup & organization
Accounts: alro65@gmail.com, alro65usa@gmail.com
"""

import os
import sys
import base64
import re
import json
import pickle
import time
import urllib.request

sys.stdout.reconfigure(encoding='utf-8')
from datetime import datetime
from google.auth.transport.requests import Request
from google.oauth2.credentials import Credentials
from google_auth_oauthlib.flow import InstalledAppFlow
from googleapiclient.discovery import build
from googleapiclient.errors import HttpError

SCOPES = [
    'https://www.googleapis.com/auth/gmail.modify',
    'https://www.googleapis.com/auth/gmail.labels',
]

CREDENTIALS_FILE = os.path.join(os.path.dirname(__file__), 'credentials.json')

# ── Label structure ────────────────────────────────────────────────────────────
LABELS_TO_CREATE = [
    "Bancos/Extractos",
    "Bancos/Promo",
    "Trabajo",
    "AutoBooking",
    "Recibos",
    "Newsletters",
]

# ── Bank senders (promo goes to Bancos/Promo, statements to Bancos/Extractos) ─
BANK_DOMAINS = [
    'bancolombia', 'davivienda', 'bbva', 'scotiabank', 'citibank',
    'hsbc', 'santander', 'chase', 'wellsfargo', 'bankofamerica',
    'capitalone', 'discover', 'americanexpress', 'amex', 'nequi',
    'daviplata', 'bold', 'bancodeoccidente', 'bancopopular',
    'coopcentral', 'ing.', 'paypal', 'stripe',
]

BANK_STATEMENT_KEYWORDS = [
    'estado de cuenta', 'extracto', 'resumen de cuenta', 'account statement',
    'transaction alert', 'alerta de transacción', 'compra realizada',
    'pago recibido', 'transferencia', 'your statement',
]

# ── Spam/promo keywords in subject or sender ──────────────────────────────────
SPAM_KEYWORDS = [
    'insurance quote', 'cotización de seguro', 'auto insurance',
    'car insurance', 'life insurance', 'health insurance',
    'get a quote', 'free quote', 'save on insurance',
    'compare rates', 'lowest rates', 'best rates',
    'final notice', 'last chance', 'act now', 'limited time',
    'you\'ve been selected', 'congratulations you won',
    'unclaimed reward', 'claim your prize',
]

PROMO_CATEGORIES = ['CATEGORY_PROMOTIONS', 'CATEGORY_UPDATES']


def authenticate(account_name: str) -> object:
    token_file = os.path.join(os.path.dirname(__file__), f'token_{account_name}.pickle')
    creds = None

    if os.path.exists(token_file):
        with open(token_file, 'rb') as f:
            creds = pickle.load(f)

    if not creds or not creds.valid:
        if creds and creds.expired and creds.refresh_token:
            creds.refresh(Request())
        else:
            flow = InstalledAppFlow.from_client_secrets_file(CREDENTIALS_FILE, SCOPES)
            creds = flow.run_local_server(port=0)
        with open(token_file, 'wb') as f:
            pickle.dump(creds, f)

    return build('gmail', 'v1', credentials=creds)


def get_or_create_label(service, name: str, label_cache: dict) -> str:
    if name in label_cache:
        return label_cache[name]

    labels = service.users().labels().list(userId='me').execute().get('labels', [])
    for lbl in labels:
        if lbl['name'].lower() == name.lower():
            label_cache[name] = lbl['id']
            return lbl['id']

    # Create nested labels parent-first
    parts = name.split('/')
    for i in range(1, len(parts) + 1):
        partial = '/'.join(parts[:i])
        if partial not in label_cache:
            exists = next((l for l in labels if l['name'].lower() == partial.lower()), None)
            if exists:
                label_cache[partial] = exists['id']
            else:
                body = {
                    'name': partial,
                    'labelListVisibility': 'labelShow',
                    'messageListVisibility': 'show',
                }
                new = service.users().labels().create(userId='me', body=body).execute()
                label_cache[partial] = new['id']
                print(f"  [+] Label creado: {partial}")

    return label_cache[name]


def get_header(headers: list, name: str) -> str:
    for h in headers:
        if h['name'].lower() == name.lower():
            return h['value']
    return ''


def extract_unsubscribe_url(headers: list) -> str | None:
    raw = get_header(headers, 'List-Unsubscribe')
    if not raw:
        return None
    # Prefer HTTPS link over mailto
    urls = re.findall(r'<(https?://[^>]+)>', raw)
    return urls[0] if urls else None


def try_unsubscribe(url: str) -> bool:
    # Guard: only follow HTTPS unsubscribe links to avoid HTTP downgrade / SSRF
    if not url.startswith('https://'):
        return False
    try:
        req = urllib.request.Request(url, headers={'User-Agent': 'Mozilla/5.0'})
        urllib.request.urlopen(req, timeout=10)
        return True
    except Exception:
        return False


def is_bank_email(sender: str, subject: str) -> tuple[bool, bool]:
    """Returns (is_bank, is_statement)."""
    combined = (sender + ' ' + subject).lower()
    if not any(b in combined for b in BANK_DOMAINS):
        return False, False
    is_statement = any(k in combined for k in BANK_STATEMENT_KEYWORDS)
    return True, is_statement


def is_spam(sender: str, subject: str) -> bool:
    combined = (sender + ' ' + subject).lower()
    return any(k in combined for k in SPAM_KEYWORDS)


def process_account(account_name: str):
    print(f"\n{'='*60}")
    print(f"  Procesando: {account_name}")
    print(f"{'='*60}")

    service = authenticate(account_name)
    label_cache = {}

    # Ensure all labels exist
    print("\n[1] Creando estructura de labels...")
    for lbl in LABELS_TO_CREATE:
        get_or_create_label(service, lbl, label_cache)

    stats = {
        'unsubscribed': 0,
        'deleted_spam': 0,
        'archived_bank_promo': 0,
        'archived_bank_statement': 0,
        'errors': 0,
    }

    # ── Pass 1: Promotions category ────────────────────────────────────────────
    print("\n[2] Analizando correos promocionales...")
    query = 'category:promotions OR category:updates'
    page_token = None

    while True:
        try:
            kwargs = {'userId': 'me', 'q': query, 'maxResults': 500}
            if page_token:
                kwargs['pageToken'] = page_token
            result = service.users().messages().list(**kwargs).execute()
        except HttpError as e:
            print(f"  Error listando mensajes: {e}")
            break

        messages = result.get('messages', [])
        if not messages:
            break

        print(f"  Encontrados {len(messages)} mensajes en esta página...")

        for msg_ref in messages:
            try:
                msg = service.users().messages().get(
                    userId='me', id=msg_ref['id'],
                    format='metadata',
                    metadataHeaders=['From', 'Subject', 'List-Unsubscribe']
                ).execute()

                headers = msg.get('payload', {}).get('headers', [])
                sender  = get_header(headers, 'From')
                subject = get_header(headers, 'Subject')
                labels  = msg.get('labelIds', [])

                is_bank, is_statement = is_bank_email(sender, subject)

                if is_bank:
                    if is_statement:
                        lbl_id = get_or_create_label(service, 'Bancos/Extractos', label_cache)
                        action = 'archive_statement'
                    else:
                        lbl_id = get_or_create_label(service, 'Bancos/Promo', label_cache)
                        action = 'archive_bank_promo'

                    service.users().messages().modify(
                        userId='me', id=msg_ref['id'],
                        body={'addLabelIds': [lbl_id], 'removeLabelIds': ['INBOX']}
                    ).execute()

                    if action == 'archive_statement':
                        stats['archived_bank_statement'] += 1
                    else:
                        stats['archived_bank_promo'] += 1

                else:
                    # Non-bank promo → unsubscribe + delete
                    unsub_url = extract_unsubscribe_url(headers)
                    if unsub_url:
                        ok = try_unsubscribe(unsub_url)
                        if ok:
                            stats['unsubscribed'] += 1
                            print(f"  [OK] Unsubscribe: {sender[:60]}")

                    service.users().messages().trash(userId='me', id=msg_ref['id']).execute()
                    stats['deleted_spam'] += 1

            except HttpError as e:
                stats['errors'] += 1
                if e.resp.status == 429:
                    print("  Rate limit — esperando 5s...")
                    time.sleep(5)

        page_token = result.get('nextPageToken')
        if not page_token:
            break

    # ── Pass 2: Explicit spam keywords in inbox ────────────────────────────────
    print("\n[3] Buscando spam por keywords en inbox...")
    spam_query = ' OR '.join(f'subject:"{k}"' for k in SPAM_KEYWORDS[:8])  # Gmail query limit

    try:
        result = service.users().messages().list(
            userId='me', q=f'in:inbox ({spam_query})', maxResults=500
        ).execute()

        messages = result.get('messages', [])
        print(f"  Encontrados {len(messages)} mensajes spam por keyword...")

        for msg_ref in messages:
            try:
                msg = service.users().messages().get(
                    userId='me', id=msg_ref['id'],
                    format='metadata',
                    metadataHeaders=['From', 'Subject', 'List-Unsubscribe']
                ).execute()

                headers = msg.get('payload', {}).get('headers', [])
                sender  = get_header(headers, 'From')
                subject = get_header(headers, 'Subject')

                unsub_url = extract_unsubscribe_url(headers)
                if unsub_url:
                    ok = try_unsubscribe(unsub_url)
                    if ok:
                        stats['unsubscribed'] += 1

                service.users().messages().trash(userId='me', id=msg_ref['id']).execute()
                stats['deleted_spam'] += 1

            except HttpError:
                stats['errors'] += 1

    except HttpError as e:
        print(f"  Error en búsqueda spam: {e}")

    # ── Summary ────────────────────────────────────────────────────────────────
    print(f"\n{'─'*40}")
    print(f"  RESUMEN — {account_name}")
    print(f"  Unsubscribes realizados : {stats['unsubscribed']}")
    print(f"  Correos eliminados      : {stats['deleted_spam']}")
    print(f"  Bancos/Promo            : {stats['archived_bank_promo']}")
    print(f"  Bancos/Extractos        : {stats['archived_bank_statement']}")
    print(f"  Errores                 : {stats['errors']}")
    print(f"{'─'*40}")

    return stats


def main():
    accounts = ['alro65', 'alro65usa']  # token files: token_alro65.pickle, token_alro65usa.pickle

    print("=" * 40)
    print("     EmailManager -- Limpieza Gmail")
    print("=" * 40)
    print("\nSe procesaran:")
    print("  - alro65@gmail.com")
    print("  - alro65usa@gmail.com")
    print("\nPara cada cuenta se abrirá el navegador para autenticación OAuth.")
    print("Usa ventana incógnito si es necesario.\n")

    input("Presiona ENTER para comenzar...")

    total_deleted = 0
    total_unsub = 0

    for acc in accounts:
        stats = process_account(acc)
        total_deleted += stats['deleted_spam']
        total_unsub   += stats['unsubscribed']

    print(f"\n{'='*40}")
    print(f"  TOTAL GENERAL")
    print(f"  Unsubscribes : {total_unsub}")
    print(f"  Eliminados   : {total_deleted}")
    print(f"{'='*40}")
    print("\nListo. Vacía la papelera en Gmail para liberar espacio.")


if __name__ == '__main__':
    main()