"""Application configuration — loaded from ``IX_*`` env vars via pydantic-settings.

Spec §9 lists every tunable. This module is the single read-point for them;
callers that need runtime config should go through :func:`get_config` rather
than ``os.environ``. The LRU cache makes the first call materialise + validate
the full config and every subsequent call return the same instance.

Cache-clearing is public (``get_config.cache_clear()``) because tests need to
re-read after ``monkeypatch.setenv``. Production code never clears the cache.
"""

from __future__ import annotations

from functools import lru_cache
from typing import Literal

from pydantic_settings import BaseSettings, SettingsConfigDict


class AppConfig(BaseSettings):
    """Typed view over the ``IX_*`` environment.

    Field names drop the ``IX_`` prefix — pydantic-settings puts it back via
    ``env_prefix``. Defaults match the spec exactly; do not change a default
    here without updating spec §9 in the same commit.
    """

    model_config = SettingsConfigDict(
        env_prefix="IX_",
        env_file=".env",
        env_file_encoding="utf-8",
        extra="ignore",
    )

    # --- Job store ---
    # Defaults assume the ix container runs with `network_mode: host` and
    # reaches the shared `postgis` and `ollama` containers on loopback;
    # spec §11 / docker-compose.yml ship that configuration.
    postgres_url: str = (
        "postgresql+asyncpg://infoxtractor:<password>"
        "@127.0.0.1:5431/infoxtractor"
    )

    # --- LLM backend ---
    ollama_url: str = "http://127.0.0.1:11434"
    default_model: str = "qwen3:14b"

    # --- OCR ---
    ocr_engine: str = "surya"

    # --- Pipeline behavior ---
    pipeline_worker_concurrency: int = 1
    pipeline_request_timeout_seconds: int = 2700
    genai_call_timeout_seconds: int = 1500
    render_max_pixels_per_page: int = 75_000_000

    # --- File fetching ---
    tmp_dir: str = "/tmp/ix"
    file_max_bytes: int = 52_428_800
    file_connect_timeout_seconds: int = 10
    file_read_timeout_seconds: int = 30

    # --- Transport / callbacks ---
    callback_timeout_seconds: int = 10

    # --- Observability ---
    log_level: str = "INFO"

    # --- Test / wiring mode ---
    # ``fake``: factories return FakeGenAIClient / FakeOCRClient and
    # ``/healthz`` probes report ok. CI sets this so the Forgejo runner
    # doesn't need access to Ollama or GPU-backed Surya. ``None`` (default)
    # means production wiring: real OllamaClient + SuryaOCRClient.
    test_mode: Literal["fake"] | None = None


@lru_cache(maxsize=1)
def get_config() -> AppConfig:
    """Return the process-wide :class:`AppConfig` (materialise on first call).

    Wrapped in ``lru_cache`` so config is parsed + validated once per process.
    Tests call ``get_config.cache_clear()`` between scenarios; nothing in
    production should touch the cache.
    """

    return AppConfig()