import os
import aiosqlite
from cryptography.fernet import Fernet

DB_PATH = os.environ.get("DB_PATH", "/data/belegimport.db")

_fernet = None

ENCRYPTED_KEYS = {"imap_password", "smtp_password", "smb_password"}

DEFAULT_SETTINGS = {
    "imap_server": "",
    "imap_port": "993",
    "imap_ssl": "true",
    "imap_username": "",
    "imap_password": "",
    "smtp_server": "",
    "smtp_port": "587",
    "smtp_ssl": "starttls",
    "smtp_username": "",
    "smtp_password": "",
    "lexoffice_email": "",
    "source_folder": "Rechnungen",
    "processed_folder": "Rechnungen/Verarbeitet",
    "interval_minutes": "5",
    "scheduler_enabled": "false",
    "fetch_since_date": "",
    # SMB
    "smb_enabled": "false",
    "smb_server": "",
    "smb_port": "445",
    "smb_username": "",
    "smb_password": "",
    "smb_domain": "",
    "smb_share": "",
    "smb_source_path": "",
    "smb_processed_path": "Verarbeitet",
    "smb_mode": "forward",
}


async def _get_fernet() -> Fernet:
    global _fernet
    if _fernet is not None:
        return _fernet

    async with aiosqlite.connect(DB_PATH) as db:
        cursor = await db.execute(
            "SELECT value FROM settings WHERE key = 'encryption_key'"
        )
        row = await cursor.fetchone()
        if row:
            key = row[0].encode()
        else:
            key = Fernet.generate_key()
            await db.execute(
                "INSERT INTO settings (key, value) VALUES ('encryption_key', ?)",
                (key.decode(),),
            )
            await db.commit()

    _fernet = Fernet(key)
    return _fernet


def _encrypt(fernet: Fernet, value: str) -> str:
    if not value:
        return ""
    return fernet.encrypt(value.encode()).decode()


def _decrypt(fernet: Fernet, value: str) -> str:
    if not value:
        return ""
    try:
        return fernet.decrypt(value.encode()).decode()
    except Exception:
        return ""


async def init_db():
    os.makedirs(os.path.dirname(DB_PATH), exist_ok=True)
    async with aiosqlite.connect(DB_PATH) as db:
        await db.execute("""
            CREATE TABLE IF NOT EXISTS settings (
                key TEXT PRIMARY KEY,
                value TEXT NOT NULL DEFAULT ''
            )
        """)
        await db.execute("""
            CREATE TABLE IF NOT EXISTS processing_log (
                id INTEGER PRIMARY KEY AUTOINCREMENT,
                timestamp TEXT NOT NULL DEFAULT (datetime('now', 'localtime')),
                email_subject TEXT,
                email_from TEXT,
                attachments_count INTEGER DEFAULT 0,
                status TEXT NOT NULL,
                error_message TEXT
            )
        """)
        await db.commit()

        # Insert default settings if not present
        for key, value in DEFAULT_SETTINGS.items():
            await db.execute(
                "INSERT OR IGNORE INTO settings (key, value) VALUES (?, ?)",
                (key, value),
            )
        await db.commit()

    # Ensure encryption key exists
    await _get_fernet()


async def get_settings() -> dict:
    fernet = await _get_fernet()
    async with aiosqlite.connect(DB_PATH) as db:
        cursor = await db.execute(
            "SELECT key, value FROM settings WHERE key != 'encryption_key'"
        )
        rows = await cursor.fetchall()

    settings = {}
    for key, value in rows:
        if key in ENCRYPTED_KEYS:
            settings[key] = _decrypt(fernet, value)
        else:
            settings[key] = value
    return settings


async def save_settings(data: dict):
    fernet = await _get_fernet()
    async with aiosqlite.connect(DB_PATH) as db:
        for key, value in data.items():
            if key == "encryption_key":
                continue
            store_value = _encrypt(fernet, value) if key in ENCRYPTED_KEYS else value
            await db.execute(
                "INSERT OR REPLACE INTO settings (key, value) VALUES (?, ?)",
                (key, store_value),
            )
        await db.commit()


async def add_log_entry(
    email_subject: str,
    email_from: str,
    attachments_count: int,
    status: str,
    error_message: str = "",
):
    async with aiosqlite.connect(DB_PATH) as db:
        await db.execute(
            """INSERT INTO processing_log
               (email_subject, email_from, attachments_count, status, error_message)
               VALUES (?, ?, ?, ?, ?)""",
            (email_subject, email_from, attachments_count, status, error_message),
        )
        await db.commit()


async def get_log_entries(limit: int = 100) -> list[dict]:
    async with aiosqlite.connect(DB_PATH) as db:
        db.row_factory = aiosqlite.Row
        cursor = await db.execute(
            "SELECT * FROM processing_log ORDER BY id DESC LIMIT ?", (limit,)
        )
        rows = await cursor.fetchall()
    return [dict(row) for row in rows]