import os
import time
import imaplib
import email
import json
import requests


IMAP_HOST = os.environ.get("IMAP_HOST", "imap.mailu.svc")
IMAP_PORT = int(os.environ.get("IMAP_PORT", "993"))
IMAP_USER = os.environ.get("IMAP_USER")
IMAP_PASS = os.environ.get("IMAP_PASS")

OLLAMA_URL = os.environ.get("OLLAMA_URL", "http://ollama.open-webui.svc:11434")
MODEL_NAME = os.environ.get("MODEL_NAME", "mail-router")

MAX_BODY_CHARS = int(os.environ.get("MAX_BODY_CHARS", "8000"))
CHECK_INTERVAL = int(os.environ.get("CHECK_INTERVAL", "30"))  # v sekundách

# povolené složky (bezpečnost proti blbosti modelu)
ALLOWED_FOLDERS = {
    "INBOX",
    "INBOX.Work",
    "INBOX.Family",
    "INBOX.Finance",
    "INBOX.Notifications",
    "INBOX.Newsletters",
    "INBOX.Social",
    "INBOX.Todo",
    "INBOX.TrashCandidates",
}


def connect_imap():
    print(f"Connecting to IMAP {IMAP_HOST}:{IMAP_PORT} as {IMAP_USER}")
    m = imaplib.IMAP4_SSL(IMAP_HOST, IMAP_PORT)
    m.login(IMAP_USER, IMAP_PASS)
    return m


def get_unseen_messages(imap_conn):
    # vždycky jako zdrojový mailbox zvolíme INBOX
    typ, _ = imap_conn.select("INBOX")
    if typ != "OK":
        print("Cannot select INBOX")
        return []

    status, data = imap_conn.search(None, 'UNSEEN')
    if status != "OK":
        print("UNSEEN search failed")
        return []

    ids = data[0].split()
    return ids


def build_prompt_from_email(msg):
    headers = []
    for h in ["From", "To", "Cc", "Subject", "Date"]:
        headers.append(f"{h}: {msg.get(h, '')}")
    headers_text = "\n".join(headers)

    body_text = ""
    if msg.is_multipart():
        for part in msg.walk():
            if part.get_content_type() == "text/plain":
                try:
                    body_text += part.get_payload(decode=True).decode(
                        part.get_content_charset() or "utf-8",
                        errors="ignore",
                    )
                except Exception:
                    continue
    else:
        try:
            body_text = msg.get_payload(decode=True).decode(
                msg.get_content_charset() or "utf-8",
                errors="ignore",
            )
        except Exception:
            body_text = ""

    body_text = body_text[:MAX_BODY_CHARS]

    return f"HEADERS:\n{headers_text}\n\nBODY:\n{body_text}"


def classify_email(prompt):
    payload = {
        "model": MODEL_NAME,
        "stream": False,
        "format": "json",
        "messages": [
            {"role": "user", "content": prompt}
        ]
    }
    r = requests.post(f"{OLLAMA_URL}/api/chat", json=payload, timeout=60)
    r.raise_for_status()
    data = r.json()
    content = data["message"]["content"]

    # debug
    print("Model raw content:", content[:200].replace("\n", " "), "...")
    return json.loads(content)


def normalize_folder(result):
    folder = result.get("folder", "INBOX")
    confidence = float(result.get("confidence", 0.0))

    # threshold – pod 0.5 necháme v INBOX
    if confidence < 0.5:
        print(f"Low confidence ({confidence}), forcing INBOX")
        return "INBOX"

    # pokud model vrátí něco mimo seznam – fallback na INBOX
    if folder not in ALLOWED_FOLDERS:
        print(f"Folder {folder} not in allowed list, forcing INBOX")
        return "INBOX"

    return folder


def ensure_folder(imap_conn, folder):
    """
    Zkontroluje existenci složky pomocí LIST a případně ji vytvoří.
    Nemění aktuálně zvolený mailbox (na rozdíl od SELECT/EXAMINE).
    """
    # LIST "" "INBOX.Foo"
    typ, mailboxes = imap_conn.list('""', f'"{folder}"')
    # mailboxes může být None nebo prázdné, pokud složka neexistuje
    if typ == "OK" and mailboxes and mailboxes[0] is not None:
        # složka existuje
        return

    print(f"Folder {folder} does not exist, creating...")
    typ, data = imap_conn.create(folder)
    if typ != "OK":
        print(f"WARNING: failed to create folder {folder}: {data}")


def move_message(imap_conn, msg_id, target_folder):
    # před přesunem zajistíme, že složka existuje
    ensure_folder(imap_conn, target_folder)

    # COPY z aktuálního mailboxu (INBOX) do target
    typ, data = imap_conn.copy(msg_id, target_folder)
    if typ != "OK":
        print(f"Failed to copy message {msg_id} to {target_folder}: {data}")
        return

    # označíme zprávu v INBOX jako smazanou a expunge
    imap_conn.store(msg_id, "+FLAGS", "\\Deleted")
    imap_conn.expunge()
    print(f"Moved message {msg_id.decode()} -> {target_folder}")


def process_once():
    imap_conn = connect_imap()
    try:
        ids = get_unseen_messages(imap_conn)
        print(f"Found {len(ids)} unseen messages in INBOX")

        for msg_id in ids:
            typ, data = imap_conn.fetch(msg_id, "(RFC822)")
            if typ != "OK":
                print(f"Fetch failed for {msg_id}")
                continue

            raw_email = data[0][1]
            msg = email.message_from_bytes(raw_email)

            prompt = build_prompt_from_email(msg)
            try:
                result = classify_email(prompt)
            except Exception as e:
                print(f"Error calling model for {msg_id}: {e}")
                continue

            target_folder = normalize_folder(result)
            move_message(imap_conn, msg_id, target_folder)

    finally:
        imap_conn.logout()


def main():
    while True:
        try:
            process_once()
        except Exception as e:
            print(f"Error in main loop: {e}")
        time.sleep(CHECK_INTERVAL)


if __name__ == "__main__":
    main()