"""
Patch defeatbeta_api to read from local parquet files with zero network.

Usage:
    from offline import enable_offline
    enable_offline("data/parquet")          # call once before first Ticker()

    from defeatbeta_api.data.ticker import Ticker
    t = Ticker("AAPL")
    t.price()                               # reads local file, no HTTP

Note: the one-time welcome banner on first import calls get_data_update_time()
once. After that, nothing touches the network.
"""
from pathlib import Path


def enable_offline(parquet_dir: str = "data/parquet") -> None:
    local_dir = Path(parquet_dir).resolve()

    # Importing these submodules triggers defeatbeta_api/__init__.py on first
    # run (prints the welcome banner — one network call). After that it's a
    # no-op because _welcome_printed is True.
    from defeatbeta_api.client.hugging_face_client import HuggingFaceClient
    import defeatbeta_api.client.duckdb_client as _duckdb_mod
    from defeatbeta_api.client.duckdb_client import DuckDBClient
    from defeatbeta_api.client.duckdb_conf import Configuration
    from defeatbeta_api.data.company_meta import CompanyMeta
    from defeatbeta_api.utils.util import validate_memory_limit

    # 1. Redirect every table URL to a local parquet file
    def _local_url(self, table: str) -> str:
        path = local_dir / f"{table}.parquet"
        if not path.exists():
            raise FileNotFoundError(
                f"Local parquet not found: {path}\n"
                f"Run download_data.py first."
            )
        return str(path)

    HuggingFaceClient.get_url_path = _local_url

    # 2. Return a fixed update time (used by beta() and the welcome banner)
    HuggingFaceClient.get_data_update_time = lambda self: "offline"

    # 3. Skip the startup cache-validation (hits HuggingFace spec.json)
    DuckDBClient._validate_httpfs_cache = lambda self: None

    # 4. Skip "INSTALL cache_httpfs FROM community" (hits DuckDB extension registry)
    #    and all the cache_httpfs SET GLOBAL lines that follow — not needed for
    #    local files. Keep only memory and thread settings.
    def _minimal_settings(self):
        return [
            f"SET GLOBAL memory_limit = '{validate_memory_limit(self.memory_limit)}'",
            f"SET GLOBAL threads = {self.threads}",
        ]

    Configuration.get_duckdb_settings = _minimal_settings

    # 5. Redirect company_tickers.json to local file
    CompanyMeta.COMPANY_TICKERS_URL = str(local_dir / "company_tickers.json")

    # 6. Reset the DuckDB singleton so the next Ticker() call reinitialises
    #    using the patched Configuration (no cache_httpfs install/load)
    _duckdb_mod._instance = None

    print(f"[offline] defeatbeta_api patched → reading from {local_dir}")