"""Runtime configuration read from environment variables.

AppFactory injects variables through the generated runtime .env file, so every
option below has a safe default and the service starts without any variable set.
"""

import os
from dataclasses import dataclass, field
from functools import lru_cache


def _bool(name: str, default: bool) -> bool:
    raw = os.getenv(name)
    if raw is None or raw.strip() == "":
        return default
    return raw.strip().lower() in ("1", "true", "yes", "on")


def _int(name: str, default: int) -> int:
    raw = os.getenv(name)
    if raw is None or raw.strip() == "":
        return default
    try:
        return int(raw)
    except ValueError:
        return default


def _list(name: str) -> list[str]:
    raw = os.getenv(name, "")
    return [item.strip() for item in raw.split(",") if item.strip()]


@dataclass(frozen=True)
class Settings:
    app_name: str = field(default_factory=lambda: os.getenv("APP_NAME", "html-to-pdf"))
    app_version: str = field(default_factory=lambda: os.getenv("APP_VERSION", "1.0.0"))
    root_path: str = field(
        default_factory=lambda: os.getenv("ROOT_PATH") or os.getenv("BASE_PATH") or ""
    )
    log_level: str = field(default_factory=lambda: os.getenv("LOG_LEVEL", "INFO").upper())

    # Job queue
    workers: int = field(default_factory=lambda: _int("WORKERS", 2))
    queue_max_size: int = field(default_factory=lambda: _int("QUEUE_MAX_SIZE", 100))
    sync_timeout_seconds: int = field(default_factory=lambda: _int("SYNC_TIMEOUT_SECONDS", 60))
    job_result_ttl_seconds: int = field(default_factory=lambda: _int("JOB_RESULT_TTL_SECONDS", 3600))
    storage_dir: str = field(default_factory=lambda: os.getenv("STORAGE_DIR", "/tmp/html-to-pdf"))

    # Engines
    default_engine: str = field(default_factory=lambda: os.getenv("DEFAULT_ENGINE", "auto"))
    chromium_enabled: bool = field(default_factory=lambda: _bool("CHROMIUM_ENABLED", True))
    chromium_restart_after_jobs: int = field(
        default_factory=lambda: _int("CHROMIUM_RESTART_AFTER_JOBS", 50)
    )

    # Network
    fetch_timeout_seconds: int = field(default_factory=lambda: _int("FETCH_TIMEOUT_SECONDS", 30))
    asset_timeout_seconds: int = field(default_factory=lambda: _int("ASSET_TIMEOUT_SECONDS", 10))
    max_redirects: int = field(default_factory=lambda: _int("MAX_REDIRECTS", 5))

    # SSRF protection. Blocking is on by default and can be widened or narrowed.
    ssrf_block_private: bool = field(default_factory=lambda: _bool("SSRF_BLOCK_PRIVATE", True))
    ssrf_extra_blocked_cidrs: list[str] = field(default_factory=lambda: _list("SSRF_EXTRA_BLOCKED_CIDRS"))
    ssrf_allowed_hosts: list[str] = field(default_factory=lambda: _list("SSRF_ALLOWED_HOSTS"))

    # Optional limits. Zero means no limit, which is the default on purpose.
    max_pages: int = field(default_factory=lambda: _int("MAX_PAGES", 0))
    max_html_bytes: int = field(default_factory=lambda: _int("MAX_HTML_BYTES", 0))
    max_render_seconds: int = field(default_factory=lambda: _int("MAX_RENDER_SECONDS", 0))

    # Callback delivery
    callback_timeout_seconds: int = field(default_factory=lambda: _int("CALLBACK_TIMEOUT_SECONDS", 15))
    callback_retries: int = field(default_factory=lambda: _int("CALLBACK_RETRIES", 3))


@lru_cache(maxsize=1)
def get_settings() -> Settings:
    return Settings()