"""Abstract exchange-event seam for DITAv2 (spec G3).

ExchangeEvent is the normalised, exchange-agnostic type that flows from
the BingX adapter (or poll-failover synthesizer) into AccountProjectionV2
and the reconcile layer.  No BingX field names, URLs, or listenKey
semantics cross this boundary.

Both the WebSocket path and the REST-poll path produce the same
ExchangeEvent types so that the two sources are interchangeable — this is
the VST↔LIVE symmetry guarantee (gate G3 mode-parity test).
"""

from __future__ import annotations

from dataclasses import dataclass, field
from enum import Enum
from typing import Dict, Tuple


class ExchangeEventKind(str, Enum):
    FULL_FILL = "FULL_FILL"
    PARTIAL_FILL = "PARTIAL_FILL"
    ORDER_ACK = "ORDER_ACK"
    ORDER_REJECT = "ORDER_REJECT"
    CANCEL_ACK = "CANCEL_ACK"
    CANCEL_REJECT = "CANCEL_REJECT"
    ACCOUNT_UPDATE = "ACCOUNT_UPDATE"    # wallet balance / margin facts
    POSITION_UPDATE = "POSITION_UPDATE"  # open-position facts
    FUNDING_FEE = "FUNDING_FEE"
    RECONNECTED = "RECONNECTED"          # adapter internal — stream resumed
    UNKNOWN = "UNKNOWN"


@dataclass(frozen=True)
class ExchangePosition:
    """Single open position as normalised by the adapter."""
    symbol: str = ""
    qty: float = 0.0
    entry_price: float = 0.0
    mark_price: float = 0.0
    unrealized_pnl: float = 0.0
    leverage: float = 1.0
    side: str = ""   # "LONG" | "SHORT"


@dataclass(frozen=True)
class ExchangeEvent:
    """
    Normalised exchange event — the abstract seam between the adapter
    (BingX WS or REST poll) and the kernel/account layer.

    Immutable.  All exchange-specific field names are resolved by the
    adapter before this type is constructed.  Callers should check `kind`
    before reading kind-specific fields (fill_price/qty, wallet_balance,
    funding_amount, etc.) — unused fields default to zero/empty.
    """

    kind: ExchangeEventKind
    event_id: str                          # dedup key (venue-assigned or synthetic uuid)
    exchange_ts: int                       # exchange-assigned timestamp ms

    # --- FILL / PARTIAL_FILL ---
    fill_price: float = 0.0
    fill_qty: float = 0.0                  # incremental fill quantity
    fee: float = 0.0
    fee_asset: str = ""
    realized_pnl: float = 0.0
    order_id: str = ""                     # venue order id
    client_order_id: str = ""
    symbol: str = ""

    # --- ACCOUNT_UPDATE ---
    wallet_balance: float = 0.0
    available_margin: float = 0.0
    used_margin: float = 0.0
    maint_margin: float = 0.0

    # --- POSITION_UPDATE ---
    positions: Tuple[ExchangePosition, ...] = ()

    # --- FUNDING_FEE ---
    funding_amount: float = 0.0           # positive = received, negative = paid
    funding_ts: int = 0

    # --- Order type / maker-taker ---
    is_maker: bool = False                 # True when limit order rested and filled (maker)

    # --- Source metadata ---
    source: str = "ws"                    # "ws" | "poll"
    raw: Dict = field(default_factory=dict)  # original frame (debug only)

    def is_fill(self) -> bool:
        return self.kind in {ExchangeEventKind.FULL_FILL, ExchangeEventKind.PARTIAL_FILL}