from __future__ import annotations

import json
from dataclasses import dataclass
from datetime import datetime, timezone
from typing import Dict, Any

from .config import dht_config
from .crypto import digest_hex


def _json_dumps(data: Dict[str, Any]) -> bytes:
    return json.dumps(data, sort_keys=True, separators=(",", ":")).encode()


@dataclass(frozen=True)
class MetaKey:
    content_id: str
    schema_version: str = dht_config.schema_version

    def fingerprint(self) -> str:
        return digest_hex(self.serialize())

    def serialize(self) -> bytes:
        return _json_dumps({"schema_version": self.schema_version, "content_id": self.content_id, "type": "meta"})

    def __str__(self) -> str:
        return f"meta:{self.schema_version}:{self.content_id}"


@dataclass(frozen=True)
class MembershipKey:
    node_id: str
    schema_version: str = dht_config.schema_version

    def fingerprint(self) -> str:
        return digest_hex(self.serialize())

    def serialize(self) -> bytes:
        return _json_dumps({"schema_version": self.schema_version, "node_id": self.node_id, "type": "membership"})

    def __str__(self) -> str:
        return f"membership:{self.schema_version}:{self.node_id}"


@dataclass(frozen=True)
class MetricKey:
    content_id: str
    window_id: str
    schema_version: str = dht_config.schema_version

    @classmethod
    def window_for(cls, timestamp: float, window_size: int | None = None) -> str:
        win = int(timestamp // (window_size or dht_config.window_size))
        return datetime.fromtimestamp(win * (window_size or dht_config.window_size), tz=timezone.utc).strftime("%Y%m%d%H")

    def fingerprint(self) -> str:
        return digest_hex(self.serialize())

    def serialize(self) -> bytes:
        return _json_dumps(
            {
                "schema_version": self.schema_version,
                "content_id": self.content_id,
                "window_id": self.window_id,
                "type": "metric",
            }
        )

    def __str__(self) -> str:
        return f"metric:{self.schema_version}:{self.content_id}:{self.window_id}"