"""
MCLogger – Panel-Datenbank-Operationen
Verwaltet Nutzer, Gruppen, Mitgliedschaften (PANEL_DB)
und verschlüsselte MC-DB-Zugangsdaten (CREDS_DB).
"""
import json
import secrets
from datetime import datetime, timedelta
import pymysql
import pymysql.cursors
from config import Config
from crypto import generate_salt, hash_password, verify_password, encrypt_str, decrypt_str


# ─────────────────────────────────────────────────────────────
# Datenbankverbindungen
# ─────────────────────────────────────────────────────────────

def get_panel_db():
    return pymysql.connect(
        host=Config.PANEL_DB_HOST,
        port=Config.PANEL_DB_PORT,
        user=Config.PANEL_DB_USER,
        password=Config.PANEL_DB_PASSWORD,
        database=Config.PANEL_DB_NAME,
        charset="utf8mb4",
        cursorclass=pymysql.cursors.DictCursor,
        autocommit=True,
    )


def get_creds_db():
    return pymysql.connect(
        host=Config.CREDS_DB_HOST,
        port=Config.CREDS_DB_PORT,
        user=Config.CREDS_DB_USER,
        password=Config.CREDS_DB_PASSWORD,
        database=Config.CREDS_DB_NAME,
        charset="utf8mb4",
        cursorclass=pymysql.cursors.DictCursor,
        autocommit=True,
    )


def _panel_query(sql, args=None, fetchone=False, write=False):
    conn = get_panel_db()
    try:
        with conn.cursor() as cur:
            cur.execute(sql, args or ())
            if write:
                return cur.lastrowid
            return cur.fetchone() if fetchone else cur.fetchall()
    finally:
        conn.close()


def _creds_query(sql, args=None, fetchone=False, write=False):
    conn = get_creds_db()
    try:
        with conn.cursor() as cur:
            cur.execute(sql, args or ())
            if write:
                return cur.lastrowid
            return cur.fetchone() if fetchone else cur.fetchall()
    finally:
        conn.close()


# ─────────────────────────────────────────────────────────────
# Initialisierung – Tabellen anlegen
# ─────────────────────────────────────────────────────────────

PANEL_SCHEMA = [
    """CREATE TABLE IF NOT EXISTS users (
        id           INT AUTO_INCREMENT PRIMARY KEY,
        username     VARCHAR(50) UNIQUE NOT NULL,
        email        VARCHAR(255) UNIQUE NOT NULL,
        password_hash VARCHAR(255) NOT NULL,
        salt         VARCHAR(64) NOT NULL,
        is_site_admin TINYINT(1) DEFAULT 0,
        created_at   TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
        last_login   TIMESTAMP NULL
    ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4""",

    """CREATE TABLE IF NOT EXISTS user_groups (
        id          INT AUTO_INCREMENT PRIMARY KEY,
        name        VARCHAR(100) UNIQUE NOT NULL,
        description TEXT,
        created_at  TIMESTAMP DEFAULT CURRENT_TIMESTAMP
    ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4""",

    """CREATE TABLE IF NOT EXISTS group_members (
        id          INT AUTO_INCREMENT PRIMARY KEY,
        user_id     INT NOT NULL,
        group_id    INT NOT NULL,
        role        ENUM('group_owner','group_admin','moderator','viewer','auditor','admin','member') DEFAULT 'viewer',
        permissions JSON,
        joined_at   TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
        UNIQUE KEY uq_user_group (user_id, group_id),
        FOREIGN KEY (user_id)  REFERENCES users(id)       ON DELETE CASCADE,
        FOREIGN KEY (group_id) REFERENCES user_groups(id) ON DELETE CASCADE
    ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4""",

    """CREATE TABLE IF NOT EXISTS group_invites (
        id               INT AUTO_INCREMENT PRIMARY KEY,
        group_id         INT NOT NULL,
        invited_username VARCHAR(50) NOT NULL,
        invited_email    VARCHAR(255) NOT NULL,
        role             ENUM('group_owner','group_admin','moderator','viewer','auditor','admin','member') DEFAULT 'viewer',
        token            VARCHAR(128) UNIQUE NOT NULL,
        created_by_user_id INT NOT NULL,
        created_at       TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
        expires_at       DATETIME NOT NULL,
        last_sent_at     DATETIME NULL,
        send_count       INT NOT NULL DEFAULT 0,
        accepted_at      DATETIME NULL,
        revoked_at       DATETIME NULL,
        UNIQUE KEY uq_group_pending_invite_email (group_id, invited_email, revoked_at, accepted_at),
        FOREIGN KEY (group_id) REFERENCES user_groups(id) ON DELETE CASCADE,
        FOREIGN KEY (created_by_user_id) REFERENCES users(id) ON DELETE CASCADE
    ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4""",
]

CREDS_SCHEMA = [
    """CREATE TABLE IF NOT EXISTS group_databases (
        id           INT AUTO_INCREMENT PRIMARY KEY,
        group_id     INT UNIQUE NOT NULL,
        enc_host     TEXT NOT NULL,
        enc_port     TEXT NOT NULL,
        enc_user     TEXT NOT NULL,
        enc_password TEXT NOT NULL,
        enc_database TEXT NOT NULL,
        updated_at   TIMESTAMP DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP
    ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4""",

    """CREATE TABLE IF NOT EXISTS site_mail_settings (
        id              INT AUTO_INCREMENT PRIMARY KEY,
        config_key      VARCHAR(50) UNIQUE NOT NULL,
        enc_host        TEXT NOT NULL,
        enc_port        TEXT NOT NULL,
        enc_username    TEXT NOT NULL,
        enc_password    TEXT NOT NULL,
        enc_from_email  TEXT NOT NULL,
        enc_from_name   TEXT,
        enc_use_tls     TEXT NOT NULL,
        updated_at      TIMESTAMP DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP
    ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4""",
]


def init_databases():
    """Erstellt alle benötigten Tabellen falls nicht vorhanden."""
    panel = get_panel_db()
    try:
        with panel.cursor() as cur:
            for stmt in PANEL_SCHEMA:
                cur.execute(stmt)
            # Best-effort migrations for existing installs.
            try:
                cur.execute(
                    "ALTER TABLE group_members MODIFY role ENUM('group_owner','group_admin','moderator','viewer','auditor','admin','member') DEFAULT 'viewer'"
                )
            except Exception:
                pass
            try:
                cur.execute(
                    "ALTER TABLE group_invites MODIFY role ENUM('group_owner','group_admin','moderator','viewer','auditor','admin','member') DEFAULT 'viewer'"
                )
            except Exception:
                pass
            try:
                cur.execute("ALTER TABLE group_invites ADD COLUMN last_sent_at DATETIME NULL")
            except Exception:
                pass
            try:
                cur.execute("ALTER TABLE group_invites ADD COLUMN send_count INT NOT NULL DEFAULT 0")
            except Exception:
                pass
    finally:
        panel.close()

    creds = get_creds_db()
    try:
        with creds.cursor() as cur:
            for stmt in CREDS_SCHEMA:
                cur.execute(stmt)
    finally:
        creds.close()


# ─────────────────────────────────────────────────────────────
# Nutzer
# ─────────────────────────────────────────────────────────────

def create_user(username: str, email: str, password: str, is_site_admin: bool = False) -> int:
    salt = generate_salt()
    pw_hash = hash_password(password, salt)
    return _panel_query(
        "INSERT INTO users (username, email, password_hash, salt, is_site_admin) VALUES (%s,%s,%s,%s,%s)",
        (username, email, pw_hash, salt, int(is_site_admin)), write=True
    )


def create_user_for_group(username: str, email: str, password: str, group_id: int, role: str = "viewer") -> int:
    """Create a non-site-admin user and assign them to a group atomically."""
    permissions = Config.DEFAULT_PERMISSIONS
    salt = generate_salt()
    pw_hash = hash_password(password, salt)

    conn = get_panel_db()
    conn.autocommit(False)
    try:
        with conn.cursor() as cur:
            cur.execute(
                "INSERT INTO users (username, email, password_hash, salt, is_site_admin) VALUES (%s,%s,%s,%s,%s)",
                (username, email, pw_hash, salt, 0),
            )
            user_id = cur.lastrowid
            cur.execute(
                "INSERT INTO group_members (user_id, group_id, role, permissions) VALUES (%s,%s,%s,%s)",
                (user_id, group_id, role, json.dumps(permissions)),
            )
        conn.commit()
        return user_id
    except Exception:
        conn.rollback()
        raise
    finally:
        conn.close()


def create_group_invite(group_id: int, username: str, email: str, role: str, created_by_user_id: int) -> str:
    expires_at = datetime.utcnow() + timedelta(hours=Config.INVITE_EXPIRY_HOURS)
    token = secrets.token_urlsafe(32)
    _panel_query(
        "INSERT INTO group_invites (group_id, invited_username, invited_email, role, token, created_by_user_id, expires_at, last_sent_at, send_count) "
        "VALUES (%s,%s,%s,%s,%s,%s,%s,NULL,0)",
        (group_id, username, email, role, token, created_by_user_id, expires_at),
        write=True,
    )
    return token


def list_active_group_invites(group_id: int):
    return _panel_query(
        "SELECT gi.*, u.username AS created_by_username "
        "FROM group_invites gi "
        "JOIN users u ON u.id = gi.created_by_user_id "
        "WHERE gi.group_id=%s AND gi.accepted_at IS NULL AND gi.revoked_at IS NULL AND gi.expires_at > UTC_TIMESTAMP() "
        "ORDER BY gi.created_at DESC",
        (group_id,),
    )


def count_active_group_invites(group_id: int) -> int:
    row = _panel_query(
        "SELECT COUNT(*) AS c FROM group_invites WHERE group_id=%s AND accepted_at IS NULL AND revoked_at IS NULL AND expires_at > UTC_TIMESTAMP()",
        (group_id,),
        fetchone=True,
    )
    return int(row["c"]) if row else 0


def get_active_invite_by_email(group_id: int, email: str):
    return _panel_query(
        "SELECT * FROM group_invites WHERE group_id=%s AND invited_email=%s "
        "AND accepted_at IS NULL AND revoked_at IS NULL AND expires_at > UTC_TIMESTAMP()",
        (group_id, email),
        fetchone=True,
    )


def get_active_invite_by_username(group_id: int, username: str):
    return _panel_query(
        "SELECT * FROM group_invites WHERE group_id=%s AND invited_username=%s "
        "AND accepted_at IS NULL AND revoked_at IS NULL AND expires_at > UTC_TIMESTAMP()",
        (group_id, username),
        fetchone=True,
    )


def get_group_invite_by_id(invite_id: int, group_id: int):
    return _panel_query(
        "SELECT * FROM group_invites WHERE id=%s AND group_id=%s",
        (invite_id, group_id),
        fetchone=True,
    )


def get_invite_by_token(token: str):
    return _panel_query(
        "SELECT gi.*, g.name AS group_name, u.username AS created_by_username "
        "FROM group_invites gi "
        "JOIN user_groups g ON g.id = gi.group_id "
        "JOIN users u ON u.id = gi.created_by_user_id "
        "WHERE gi.token=%s",
        (token,),
        fetchone=True,
    )


def revoke_group_invite(invite_id: int, group_id: int):
    _panel_query(
        "UPDATE group_invites SET revoked_at=UTC_TIMESTAMP() WHERE id=%s AND group_id=%s AND accepted_at IS NULL AND revoked_at IS NULL",
        (invite_id, group_id),
        write=True,
    )


def mark_group_invite_sent(invite_id: int, group_id: int):
    _panel_query(
        "UPDATE group_invites SET last_sent_at=UTC_TIMESTAMP(), send_count=send_count+1 WHERE id=%s AND group_id=%s",
        (invite_id, group_id),
        write=True,
    )


def accept_group_invite(token: str, password: str) -> dict | None:
    invite = get_invite_by_token(token)
    if not invite:
        return None
    if invite.get("accepted_at") or invite.get("revoked_at"):
        return None
    if invite["expires_at"] <= datetime.utcnow():
        return None

    permissions = Config.DEFAULT_PERMISSIONS
    salt = generate_salt()
    pw_hash = hash_password(password, salt)

    conn = get_panel_db()
    conn.autocommit(False)
    try:
        with conn.cursor() as cur:
            cur.execute("SELECT id FROM users WHERE username=%s OR email=%s", (invite["invited_username"], invite["invited_email"]))
            if cur.fetchone():
                conn.rollback()
                return {"error": "username_or_email_taken"}

            cur.execute(
                "INSERT INTO users (username, email, password_hash, salt, is_site_admin) VALUES (%s,%s,%s,%s,%s)",
                (invite["invited_username"], invite["invited_email"], pw_hash, salt, 0),
            )
            user_id = cur.lastrowid
            cur.execute(
                "INSERT INTO group_members (user_id, group_id, role, permissions) VALUES (%s,%s,%s,%s)",
                (user_id, invite["group_id"], invite["role"], json.dumps(permissions)),
            )
            cur.execute(
                "UPDATE group_invites SET accepted_at=UTC_TIMESTAMP() WHERE id=%s AND accepted_at IS NULL AND revoked_at IS NULL",
                (invite["id"],),
            )
        conn.commit()
        return {"user_id": user_id, "group_id": invite["group_id"]}
    except Exception:
        conn.rollback()
        raise
    finally:
        conn.close()


def get_user_by_username(username: str):
    return _panel_query("SELECT * FROM users WHERE username=%s", (username,), fetchone=True)


def get_user_by_email(email: str):
    return _panel_query("SELECT * FROM users WHERE email=%s", (email,), fetchone=True)


def get_user_by_id(user_id: int):
    return _panel_query("SELECT * FROM users WHERE id=%s", (user_id,), fetchone=True)


def update_user(user_id: int, username: str, email: str, is_site_admin: bool):
    _panel_query(
        "UPDATE users SET username=%s, email=%s, is_site_admin=%s WHERE id=%s",
        (username, email, int(is_site_admin), user_id), write=True
    )


def change_password(user_id: int, new_password: str):
    salt = generate_salt()
    pw_hash = hash_password(new_password, salt)
    _panel_query(
        "UPDATE users SET password_hash=%s, salt=%s WHERE id=%s",
        (pw_hash, salt, user_id), write=True
    )


def delete_user(user_id: int):
    _panel_query("DELETE FROM users WHERE id=%s", (user_id,), write=True)


def check_login(username: str, password: str):
    """Prüft Anmeldedaten. Gibt den Nutzer zurück oder None."""
    user = get_user_by_username(username)
    if not user:
        return None
    if not verify_password(password, user["salt"], user["password_hash"]):
        return None
    _panel_query("UPDATE users SET last_login=NOW() WHERE id=%s", (user["id"],), write=True)
    return user


def list_all_users():
    return _panel_query(
        "SELECT u.*, COUNT(gm.group_id) AS group_count "
        "FROM users u LEFT JOIN group_members gm ON gm.user_id=u.id "
        "GROUP BY u.id ORDER BY u.username"
    )


# ─────────────────────────────────────────────────────────────
# Gruppen
# ─────────────────────────────────────────────────────────────

def create_group(name: str, description: str = "") -> int:
    return _panel_query(
        "INSERT INTO user_groups (name, description) VALUES (%s,%s)",
        (name, description), write=True
    )


def get_group_by_id(group_id: int):
    return _panel_query("SELECT * FROM user_groups WHERE id=%s", (group_id,), fetchone=True)


def get_group_by_name(name: str):
    return _panel_query("SELECT * FROM user_groups WHERE name=%s", (name,), fetchone=True)


def update_group(group_id: int, name: str, description: str):
    _panel_query(
        "UPDATE user_groups SET name=%s, description=%s WHERE id=%s",
        (name, description, group_id), write=True
    )


def delete_group(group_id: int):
    _panel_query("DELETE FROM user_groups WHERE id=%s", (group_id,), write=True)


def list_all_groups():
    return _panel_query(
        "SELECT g.*, COUNT(gm.user_id) AS member_count "
        "FROM user_groups g LEFT JOIN group_members gm ON gm.group_id=g.id "
        "GROUP BY g.id ORDER BY g.name"
    )


# ─────────────────────────────────────────────────────────────
# Gruppenmitgliedschaften
# ─────────────────────────────────────────────────────────────

def get_user_groups(user_id: int):
    return _panel_query(
        "SELECT g.*, gm.role, gm.permissions "
        "FROM user_groups g "
        "JOIN group_members gm ON gm.group_id=g.id "
        "WHERE gm.user_id=%s ORDER BY g.name",
        (user_id,)
    )


def get_group_member(user_id: int, group_id: int):
    return _panel_query(
        "SELECT * FROM group_members WHERE user_id=%s AND group_id=%s",
        (user_id, group_id), fetchone=True
    )


def get_group_members(group_id: int):
    return _panel_query(
        "SELECT u.id, u.username, u.email, u.last_login, gm.role, gm.permissions, gm.joined_at "
        "FROM group_members gm "
        "JOIN users u ON u.id=gm.user_id "
        "WHERE gm.group_id=%s ORDER BY gm.role DESC, u.username",
        (group_id,)
    )


def add_group_member(user_id: int, group_id: int, role: str = "viewer", permissions: dict = None):
    if permissions is None:
        permissions = Config.DEFAULT_PERMISSIONS
    _panel_query(
        "INSERT INTO group_members (user_id, group_id, role, permissions) VALUES (%s,%s,%s,%s) "
        "ON DUPLICATE KEY UPDATE role=VALUES(role), permissions=VALUES(permissions)",
        (user_id, group_id, role, json.dumps(permissions)), write=True
    )


def update_member(user_id: int, group_id: int, role: str, permissions: dict):
    _panel_query(
        "UPDATE group_members SET role=%s, permissions=%s WHERE user_id=%s AND group_id=%s",
        (role, json.dumps(permissions), user_id, group_id), write=True
    )


def remove_group_member(user_id: int, group_id: int):
    _panel_query(
        "DELETE FROM group_members WHERE user_id=%s AND group_id=%s",
        (user_id, group_id), write=True
    )


def get_permissions(user_id: int, group_id: int) -> dict:
    """Gibt die Berechtigungen des Nutzers in der Gruppe zurück."""
    member = get_group_member(user_id, group_id)
    if not member:
        return {}
    raw = member.get("permissions")
    if isinstance(raw, str):
        return json.loads(raw)
    if isinstance(raw, dict):
        return raw
    return {}


# ─────────────────────────────────────────────────────────────
# MC-Datenbank-Zugangsdaten (verschlüsselt)
# ─────────────────────────────────────────────────────────────

def set_group_db_creds(group_id: int, host: str, port: int, user: str, password: str, database: str):
    """Verschlüsselt und speichert die MC-DB-Zugangsdaten einer Gruppe."""
    _creds_query(
        "INSERT INTO group_databases (group_id, enc_host, enc_port, enc_user, enc_password, enc_database) "
        "VALUES (%s,%s,%s,%s,%s,%s) "
        "ON DUPLICATE KEY UPDATE enc_host=VALUES(enc_host), enc_port=VALUES(enc_port), "
        "enc_user=VALUES(enc_user), enc_password=VALUES(enc_password), enc_database=VALUES(enc_database)",
        (group_id,
         encrypt_str(host),
         encrypt_str(str(port)),
         encrypt_str(user),
         encrypt_str(password),
         encrypt_str(database)),
        write=True
    )


def get_group_db_creds(group_id: int) -> dict | None:
    """Gibt die entschlüsselten MC-DB-Zugangsdaten zurück oder None."""
    row = _creds_query(
        "SELECT * FROM group_databases WHERE group_id=%s",
        (group_id,), fetchone=True
    )
    if not row:
        return None
    return {
        "host":     decrypt_str(row["enc_host"]),
        "port":     int(decrypt_str(row["enc_port"])),
        "user":     decrypt_str(row["enc_user"]),
        "password": decrypt_str(row["enc_password"]),
        "database": decrypt_str(row["enc_database"]),
    }


def delete_group_db_creds(group_id: int):
    _creds_query("DELETE FROM group_databases WHERE group_id=%s", (group_id,), write=True)


def has_db_configured(group_id: int) -> bool:
    row = _creds_query(
        "SELECT id FROM group_databases WHERE group_id=%s",
        (group_id,), fetchone=True
    )
    return row is not None


def set_site_mail_settings(host: str, port: int, username: str, password: str, from_email: str, from_name: str, use_tls: bool):
    _creds_query(
        "INSERT INTO site_mail_settings (config_key, enc_host, enc_port, enc_username, enc_password, enc_from_email, enc_from_name, enc_use_tls) "
        "VALUES (%s,%s,%s,%s,%s,%s,%s,%s) "
        "ON DUPLICATE KEY UPDATE enc_host=VALUES(enc_host), enc_port=VALUES(enc_port), enc_username=VALUES(enc_username), "
        "enc_password=VALUES(enc_password), enc_from_email=VALUES(enc_from_email), enc_from_name=VALUES(enc_from_name), enc_use_tls=VALUES(enc_use_tls)",
        (
            "primary",
            encrypt_str(host),
            encrypt_str(str(port)),
            encrypt_str(username),
            encrypt_str(password),
            encrypt_str(from_email),
            encrypt_str(from_name or ""),
            encrypt_str("1" if use_tls else "0"),
        ),
        write=True,
    )


def get_site_mail_settings() -> dict | None:
    row = _creds_query("SELECT * FROM site_mail_settings WHERE config_key=%s", ("primary",), fetchone=True)
    if not row:
        return None
    return {
        "host": decrypt_str(row["enc_host"]),
        "port": int(decrypt_str(row["enc_port"])),
        "username": decrypt_str(row["enc_username"]),
        "password": decrypt_str(row["enc_password"]),
        "from_email": decrypt_str(row["enc_from_email"]),
        "from_name": decrypt_str(row["enc_from_name"]) if row.get("enc_from_name") else "",
        "use_tls": decrypt_str(row["enc_use_tls"]) == "1",
        "updated_at": row["updated_at"],
    }


def delete_site_mail_settings():
    _creds_query("DELETE FROM site_mail_settings WHERE config_key=%s", ("primary",), write=True)


def has_site_mail_settings() -> bool:
    row = _creds_query("SELECT id FROM site_mail_settings WHERE config_key=%s", ("primary",), fetchone=True)
    return row is not None