from sqlalchemy import inspect, text
from sqlmodel import Session, create_engine

from core.settings import (
    DATABASE_ECHO,
    DATABASE_MAX_OVERFLOW,
    DATABASE_POOL_RECYCLE,
    DATABASE_POOL_SIZE,
    DATABASE_POOL_TIMEOUT,
    DATABASE_URL,
)

_engine_kwargs = {
    "echo": DATABASE_ECHO,
    "pool_pre_ping": True,
    "pool_size": DATABASE_POOL_SIZE,
    "max_overflow": DATABASE_MAX_OVERFLOW,
    "pool_timeout": DATABASE_POOL_TIMEOUT,
    "pool_recycle": DATABASE_POOL_RECYCLE,
}

engine = create_engine(DATABASE_URL, **_engine_kwargs)

BOT_INSTANCE_TABLE = "bot_instance"
BOT_MESSAGE_TABLE = "bot_message"
BOT_IMAGE_TABLE = "bot_image"
BOT_REQUEST_USAGE_TABLE = "bot_request_usage"
BOT_ACTIVITY_EVENT_TABLE = "bot_activity_event"
SYS_LOGIN_LOG_TABLE = "sys_login_log"
SYS_SETTING_TABLE = "sys_setting"
REQUIRED_TABLES = (
    BOT_INSTANCE_TABLE,
    BOT_MESSAGE_TABLE,
    BOT_IMAGE_TABLE,
    BOT_REQUEST_USAGE_TABLE,
    BOT_ACTIVITY_EVENT_TABLE,
    SYS_LOGIN_LOG_TABLE,
    SYS_SETTING_TABLE,
    "skill_market_item",
    "bot_skill_install",
    "topic_topic",
    "topic_item",
)

REQUIRED_SYS_SETTING_KEYS = (
    "page_size",
    "chat_pull_page_size",
    "command_auto_unlock_seconds",
    "auth_token_ttl_hours",
    "auth_token_max_active",
    "upload_max_mb",
    "allowed_attachment_extensions",
    "workspace_download_extensions",
    "speech_enabled",
    "activity_event_retention_days",
)


def _validate_required_tables() -> None:
    inspector = inspect(engine)
    missing = [table_name for table_name in REQUIRED_TABLES if not inspector.has_table(table_name)]
    if missing:
        raise RuntimeError(
            "Database schema is not initialized. "
            f"Missing tables: {', '.join(missing)}. "
            "Run scripts/init-full-db.sh or apply scripts/sql/create-tables.sql before starting the backend."
        )


def _validate_required_sys_settings() -> None:
    placeholders = ", ".join(f":k{i}" for i, _ in enumerate(REQUIRED_SYS_SETTING_KEYS))
    params = {f"k{i}": key for i, key in enumerate(REQUIRED_SYS_SETTING_KEYS)}
    with engine.connect() as conn:
        rows = conn.execute(
            text(f'SELECT key FROM "{SYS_SETTING_TABLE}" WHERE key IN ({placeholders})'),
            params,
        ).scalars().all()
    present = {str(row or "").strip() for row in rows if str(row or "").strip()}
    missing = [key for key in REQUIRED_SYS_SETTING_KEYS if key not in present]
    if missing:
        raise RuntimeError(
            "Database seed data is not initialized. "
            f"Missing sys_setting keys: {', '.join(missing)}. "
            "Run scripts/init-full-db.sh or apply scripts/sql/init-data.sql before starting the backend."
        )


def init_database() -> None:
    with engine.connect() as conn:
        conn.execute(text("SELECT 1"))
    _validate_required_tables()
    _validate_required_sys_settings()


def get_session():
    with Session(engine) as session:
        yield session