from __future__ import annotations

import os
from dataclasses import dataclass
from pathlib import Path


_PROJECT_ROOT = Path(__file__).resolve().parents[1]
_DEFAULT_ALLOWED_MIME_TYPES = (
    "image/*",
    "audio/*",
    "application/pdf",
    "text/html",
    "application/xhtml+xml",
    "text/plain",
    "text/markdown",
    "text/csv",
    "application/json",
    "application/msword",
    "application/vnd.openxmlformats-officedocument.wordprocessingml.document",
    "application/vnd.ms-excel",
    "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet",
    "application/vnd.ms-powerpoint",
    "application/vnd.openxmlformats-officedocument.presentationml.presentation",
)


@dataclass(frozen=True)
class GatewayConfig:
    backend_base_url: str = "http://127.0.0.1:1995"
    database_path: Path = _PROJECT_ROOT / "data" / "memory_gateway.sqlite3"
    storage_dir: Path = _PROJECT_ROOT / "data" / "storage"
    resource_search_batch_size: int = 50
    max_upload_bytes: int = 25 * 1024 * 1024
    allowed_mime_types: tuple[str, ...] = _DEFAULT_ALLOWED_MIME_TYPES
    backend_ingest_attempts: int = 3
    backend_retry_delay_seconds: float = 0.25
    backend_timeout_seconds: float = 120.0

    @classmethod
    def from_env(cls) -> GatewayConfig:
        allowed_mime_types = tuple(
            item.strip()
            for item in os.environ.get(
                "MEMORY_GATEWAY_ALLOWED_MIME_TYPES",
                ",".join(_DEFAULT_ALLOWED_MIME_TYPES),
            ).split(",")
            if item.strip()
        )
        return cls(
            backend_base_url=os.environ.get(
                "MEMORY_GATEWAY_BACKEND_BASE_URL",
                "http://127.0.0.1:1995",
            ).rstrip("/"),
            database_path=Path(
                os.environ.get(
                    "MEMORY_GATEWAY_DB_PATH",
                    str(_PROJECT_ROOT / "data" / "memory_gateway.sqlite3"),
                )
            ),
            storage_dir=Path(
                os.environ.get(
                    "MEMORY_GATEWAY_STORAGE_DIR",
                    str(_PROJECT_ROOT / "data" / "storage"),
                )
            ),
            resource_search_batch_size=int(
                os.environ.get("MEMORY_GATEWAY_RESOURCE_SEARCH_BATCH_SIZE", "50")
            ),
            max_upload_bytes=int(
                os.environ.get("MEMORY_GATEWAY_MAX_UPLOAD_BYTES", str(25 * 1024 * 1024))
            ),
            allowed_mime_types=allowed_mime_types,
            backend_ingest_attempts=int(
                os.environ.get("MEMORY_GATEWAY_BACKEND_INGEST_ATTEMPTS", "3")
            ),
            backend_retry_delay_seconds=float(
                os.environ.get("MEMORY_GATEWAY_BACKEND_RETRY_DELAY_SECONDS", "0.25")
            ),
            backend_timeout_seconds=float(
                os.environ.get("MEMORY_GATEWAY_BACKEND_TIMEOUT_SECONDS", "120")
            ),
        )