from server.metrics import MetricsStoreBuilder

import time, os

class MetricsManager:
  def __init__(self, backend:str="memory", redis_url:str="redis://localhost:6379/0", ttl_seconds:int=90, key_prefix:str="snake:metrics:worker", worker_id:str|None=None):
    self.backend = (backend or "memory").strip().lower()
    self.worker_id = worker_id or f"{os.getpid()}-{int(time.time() * 1000)}"
    self.store = MetricsStoreBuilder.build(
      backend=self.backend,
      redis_url=redis_url,
      ttl_seconds=ttl_seconds,
      key_prefix=key_prefix,
    )

  async def publish_only(self, snapshot:dict) -> None:
    await self.store.publish(self.worker_id, snapshot)

  async def snapshot(self, local_snapshot:dict) -> dict:
    await self.store.publish(self.worker_id, local_snapshot)

    if self.backend != "redis":
      return local_snapshot

    snapshots = await self.store.load_all()
    if not snapshots:
      return local_snapshot
    return self._merge_snapshots(snapshots)

  async def close(self) -> None:
    await self.store.close()

  def _merge_snapshots(self, snapshots:list[dict]) -> dict:
    merged = {
      "games_started": 0,
      "games_ended": 0,
      "wins": 0,
      "losses": 0,
      "total_moves": 0,
      "total_turns": 0,
      "max_turn": 0,
      "active_games_peak": 0,
      "games_autocreated": 0,
      "http_requests_total": 0,
      "move_response_time_ms_total": 0.0,
      "move_response_time_ms_max": 0.0,
      "last_game_start_unix": 0,
      "last_game_end_unix": 0,
      "last_move_unix": 0,
      "games_stuck_removed": 0,
      "game_state_local_cache_enabled": False,
      "metrics_backend": "redis",
      "active_games": 0,
      "tracked_games": 0,
      "oldest_active_game_age_sec": 0,
      "stale_game_timeout_sec": 0,
      "active_games_stale": 0,
      "http_requests_by_endpoint": {"info": 0, "start": 0, "move": 0, "end": 0},
      "move_direction_counts": {
        "up": 0,
        "down": 0,
        "left": 0,
        "right": 0,
        "unknown": 0,
      },
    }

    for worker in snapshots:
      for metric_name in (
        "games_started",
        "games_ended",
        "wins",
        "losses",
        "total_moves",
        "total_turns",
        "games_autocreated",
        "http_requests_total",
        "games_stuck_removed",
        "active_games",
        "tracked_games",
        "active_games_stale",
      ):
        merged[metric_name] += int(worker.get(metric_name, 0))

      merged["move_response_time_ms_total"] += float(worker.get("move_response_time_ms_total", 0.0))
      merged["max_turn"] = max(merged["max_turn"], int(worker.get("max_turn", 0)))
      merged["active_games_peak"] = max(merged["active_games_peak"], int(worker.get("active_games_peak", 0)))
      merged["move_response_time_ms_max"] = max(merged["move_response_time_ms_max"], float(worker.get("move_response_time_ms_max", 0.0)))
      merged["last_game_start_unix"] = max(merged["last_game_start_unix"], int(worker.get("last_game_start_unix", 0)),)
      merged["last_game_end_unix"] = max(merged["last_game_end_unix"], int(worker.get("last_game_end_unix", 0)))
      merged["last_move_unix"] = max(merged["last_move_unix"], int(worker.get("last_move_unix", 0)))
      merged["oldest_active_game_age_sec"] = max(merged["oldest_active_game_age_sec"], int(worker.get("oldest_active_game_age_sec", 0)),)
      merged["stale_game_timeout_sec"] = max(merged["stale_game_timeout_sec"], int(worker.get("stale_game_timeout_sec", 0)),)
      merged["game_state_local_cache_enabled"] = merged["game_state_local_cache_enabled"] or bool(worker.get("game_state_local_cache_enabled", False))

      for endpoint in merged["http_requests_by_endpoint"]:
        merged["http_requests_by_endpoint"][endpoint] += int(worker.get("http_requests_by_endpoint", {}).get(endpoint, 0))
      for direction in merged["move_direction_counts"]:
        merged["move_direction_counts"][direction] += int(worker.get("move_direction_counts", {}).get(direction, 0))

    games_ended = merged["games_ended"]
    total_moves = merged["total_moves"]
    merged["avg_turns_per_game"] = round((merged["total_turns"] / games_ended) if games_ended else 0.0, 2)
    merged["win_rate"] = round((merged["wins"] / games_ended) if games_ended else 0.0, 4)
    merged["avg_move_response_ms"] = round((merged["move_response_time_ms_total"] / total_moves) if total_moves else 0.0, 2)
    return merged