from typing import Annotated

from fastapi import Header, HTTPException, status

from .config import Settings, settings


async def get_request_settings(
    tenant_id: Annotated[
        str | None,
        Header(
            alias="X-MS365-Tenant-Id",
            description="Microsoft Entra tenant id of the client (Directory / tenant ID).",
        ),
    ] = None,
    client_id: Annotated[
        str | None,
        Header(
            alias="X-MS365-Client-Id",
            description="Application (client) ID of the CSBOT Entra app registration.",
        ),
    ] = None,
    client_secret: Annotated[
        str | None,
        Header(
            alias="X-MS365-Client-Secret",
            description="Client secret VALUE of the CSBOT Entra app registration (not the secret id).",
        ),
    ] = None,
) -> Settings:
    """Per-request credentials. All three headers together, or none (then env values are used)."""
    header_values = {
        "X-MS365-Tenant-Id": tenant_id,
        "X-MS365-Client-Id": client_id,
        "X-MS365-Client-Secret": client_secret,
    }
    provided = {name: value for name, value in header_values.items() if value}
    if not provided:
        return settings

    missing = [name for name, value in header_values.items() if not value]
    if missing:
        raise HTTPException(
            status_code=status.HTTP_400_BAD_REQUEST,
            detail={"message": "Incomplete Microsoft 365 credential headers.", "missing_headers": missing},
        )

    return settings.with_credentials(
        tenant_id=provided["X-MS365-Tenant-Id"],
        client_id=provided["X-MS365-Client-Id"],
        client_secret=provided["X-MS365-Client-Secret"],
    )