"""Per-request client identity for MCP calls.

MCP clients identify themselves via an ``X-Voicebox-Client-Id`` HTTP header
(direct-HTTP clients set it in their MCP config; the stdio shim forwards it
from the ``VOICEBOX_CLIENT_ID`` env var). Middleware copies the value into a
ContextVar so tool implementations can read it without plumbing the request
object through every service call.
"""

import logging
from contextvars import ContextVar
from datetime import datetime

from starlette.middleware.base import BaseHTTPMiddleware
from starlette.requests import Request
from starlette.responses import Response
from starlette.types import ASGIApp


logger = logging.getLogger(__name__)

CLIENT_ID_HEADER = "X-Voicebox-Client-Id"

# Tool handlers read this to apply per-client voice bindings.
current_client_id: ContextVar[str | None] = ContextVar(
    "current_client_id", default=None
)

# Endpoints that consume X-Voicebox-Client-Id for its MCP-semantic
# meaning (per-client profile resolution + per-client default_personality).
# These are the paths where a stamp into last_seen_at is accurate.
# Unrelated REST traffic that happens to set the header is intentionally
# ignored so the Settings UI's "last heard from" column only reflects
# calls that actually acted on the client's bindings.
#
# - /mcp — FastMCP tool calls (voicebox.speak, voicebox.transcribe, …)
#   and the /mcp/bindings admin surface. The admin surface is never
#   called with the header in practice (the frontend manages bindings
#   over plain REST), so the `startswith("/mcp")` match doesn't cause
#   false stamps.
# - /speak — REST mirror of voicebox.speak for non-MCP agents (shell
#   scripts, ACP, A2A). Uses the same per-client binding lookup, so its
#   callers belong in the last-seen list too.
_STAMPED_PATH_PREFIXES: tuple[str, ...] = ("/mcp", "/speak")


class ClientIdMiddleware(BaseHTTPMiddleware):
    """Copy X-Voicebox-Client-Id into a ContextVar and stamp last_seen_at
    for requests that act on the caller's MCP bindings."""

    def __init__(self, app: ASGIApp) -> None:
        super().__init__(app)

    async def dispatch(self, request: Request, call_next) -> Response:
        client_id = request.headers.get(CLIENT_ID_HEADER)
        token = current_client_id.set(client_id)
        try:
            response = await call_next(request)
        finally:
            current_client_id.reset(token)

        if client_id and _is_stamped_path(request.url.path):
            _stamp_last_seen(client_id)
        return response


def _is_stamped_path(path: str) -> bool:
    # Require a path boundary so a future ``/speakers`` or ``/mcpfoo``
    # route doesn't silently inherit the stamp from ``/speak`` / ``/mcp``.
    return any(path == p or path.startswith(p + "/") for p in _STAMPED_PATH_PREFIXES)


def _stamp_last_seen(client_id: str) -> None:
    """Update or create the MCPClientBinding row for this client_id."""
    try:
        from ..database import get_db
        from ..database.models import MCPClientBinding
    except Exception:
        return
    try:
        db = next(get_db())
    except Exception:
        return
    try:
        row = (
            db.query(MCPClientBinding)
            .filter(MCPClientBinding.client_id == client_id)
            .first()
        )
        if row is None:
            row = MCPClientBinding(client_id=client_id)
            db.add(row)
        row.last_seen_at = datetime.utcnow()
        db.commit()
    except Exception:
        logger.debug(
            "Could not stamp last_seen_at for %s", client_id, exc_info=True
        )
        db.rollback()
    finally:
        db.close()