"""Shared mutable router state.

All process-wide caches, locks, in-flight task maps, queues, counters and
buffers used by the router live here. These names are only ever *mutated*
(dict/set updates, lock acquisitions, queue put/get) — never rebound — so
importing them via ``from state import …`` is safe from every module.

Rebound singletons (``config``, ``db``, ``token_worker_task``,
``flush_task``) intentionally stay in router.py so their reassignment on
startup is visible to all callers.
"""
import asyncio
from collections import defaultdict
from typing import Dict, Set


# ------------------------------------------------------------------
# In‑memory caches
# ------------------------------------------------------------------
# Successful results are cached for 300s
_models_cache: dict[str, tuple[Set[str], float]] = {}
_loaded_models_cache: dict[str, tuple[Set[str], float]] = {}
# Transient errors are cached separately per concern so that a failure
# in one path does not poison the other.
_available_error_cache: dict[str, float] = {}
_loaded_error_cache: dict[str, float] = {}
# Per-(endpoint, model) completion-path failures. A llama-server in router
# mode can keep returning /v1/models 200 OK after its delegated worker for
# a specific model dies — the probe-level caches above will not catch this.
# We record signals observed during actual completion attempts so
# choose_endpoint can avoid the affected (endpoint, model) pair without
# poisoning unrelated models on the same backend.
_completion_error_cache: dict[tuple[str, str], float] = {}
_COMPLETION_ERROR_TTL = 300

# ------------------------------------------------------------------
# Cache locks
# ------------------------------------------------------------------
_models_cache_lock = asyncio.Lock()
_loaded_models_cache_lock = asyncio.Lock()
_available_error_cache_lock = asyncio.Lock()
_loaded_error_cache_lock = asyncio.Lock()
_completion_error_cache_lock = asyncio.Lock()

# ------------------------------------------------------------------
# In-flight request tracking (prevents cache stampede)
# ------------------------------------------------------------------
_inflight_available_models: dict[str, asyncio.Task] = {}
_inflight_loaded_models: dict[str, asyncio.Task] = {}
_inflight_lock = asyncio.Lock()
_bg_refresh_available: dict[str, asyncio.Task] = {}
_bg_refresh_loaded: dict[str, asyncio.Task] = {}
_bg_refresh_lock = asyncio.Lock()

# ------------------------------------------------------------------
# Queues
# ------------------------------------------------------------------
_subscribers: Set[asyncio.Queue] = set()
_subscribers_lock = asyncio.Lock()
token_queue: asyncio.Queue[tuple[str, str, int, int]] = asyncio.Queue()

# ------------------------------------------------------------------
# HTTP client / connector cache
# ------------------------------------------------------------------
app_state = {
    "session": None,
    "connector": None,
    "probe_session": None,    # dedicated session for health/introspection probes
    "probe_connector": None,  # connection pool isolated from proxy traffic
    "socket_sessions": {},  # endpoint -> aiohttp.ClientSession(UnixConnector) for .sock endpoints
    "httpx_clients": {},    # endpoint -> httpx.AsyncClient(UDS transport) for .sock endpoints
}

# Default outbound HTTP headers attached to every backend request.
default_headers = {
    "HTTP-Referer": "https://nomyo.ai",
    "Referer": "https://nomyo.ai",
    "X-Title": "NOMYO Router",
}

# ------------------------------------------------------------------
# Token Count Buffer (for write-behind pattern)
# ------------------------------------------------------------------
# Structure: {endpoint: {model: (input_tokens, output_tokens)}}
token_buffer: dict[str, dict[str, tuple[int, int]]] = defaultdict(lambda: defaultdict(lambda: (0, 0)))
# Time series buffer with timestamp
time_series_buffer: list[dict[str, int | str]] = []
# Lock to protect buffer access from race conditions
buffer_lock = asyncio.Lock()

# Configuration for periodic flushing
FLUSH_INTERVAL = 10  # seconds

# ------------------------------------------------------------------
# Per‑endpoint per‑model active connection counters
# ------------------------------------------------------------------
usage_counts: Dict[str, Dict[str, int]] = defaultdict(lambda: defaultdict(int))
token_usage_counts: Dict[str, Dict[str, int]] = defaultdict(lambda: defaultdict(int))
usage_lock = asyncio.Lock()  # protects access to usage_counts
token_usage_lock = asyncio.Lock()

# Conversation affinity map: fingerprint -> (endpoint, model, expires_at_monotonic).
# Keeps the same conversation pinned to the endpoint that already has its
# KV-cache prefix warm. Model is stored so the dashboard can aggregate live
# entries per (endpoint, model) without recomputing fingerprints.
# Never held together with usage_lock.
_affinity_map: Dict[str, tuple[str, str, float]] = {}
_affinity_lock = asyncio.Lock()
_AFFINITY_MAX_ENTRIES = 10000