"""Slot domain data classes (REQ-001, REQ-002; dcy-020/REQ-056 asset-centric)."""
from __future__ import annotations

from dataclasses import dataclass, field
from datetime import datetime
from decimal import Decimal
from typing import Optional
from uuid import UUID

from trex_core.domain.slot.state import SlotState


@dataclass
class Slot:
    """Single daily_slot row.

    dcy-020/REQ-056 (BAT-030): the slot is a **permanent asset slot** — one row
    per (instance_key, portfolio_id) universe asset, living across trading days.
    Pool-model columns `trading_date` and `entry_count` were dropped at the
    cutover (migration 011); time attributes live on events/ledger rows, not on
    the slot. Matches docs/data-model.md.
    """

    slot_id: UUID
    status: SlotState
    symbol: Optional[str] = None
    qty: Optional[float] = None
    avg_price: Optional[float] = None
    # dcy-012 / REQ-002: side-agnostic "current pending order limit price"
    # (renamed from entry_price). Set on pending entry (buy/sell limit), cleared
    # on pending exit (→HOLDING, →INACTIVE) so a buy limit never leaks into a
    # sell order (issue #10). None => market order at dispatch.
    limit_price: Optional[float] = None
    order_id: Optional[str] = None
    strategy_id: Optional[str] = None
    broker_order_id: Optional[str] = None  # BAT-003 / REQ-011 (trex-orbit lineage)
    portfolio_id: Optional[str] = None  # BAT-006 / REQ-025; asset binding (REQ-056)
    sell_strategy_id: Optional[str] = None  # BAT-008 / REQ-047 (trex-orbit lineage)
    forced_close_at: Optional[datetime] = None  # BAT-014 / REQ-066 (trex-orbit lineage)
    stop_loss_price: Optional[Decimal] = None   # REQ-035 / BAT-010
    take_profit_price: Optional[Decimal] = None  # REQ-035 / BAT-010
    created_at: Optional[datetime] = None
    updated_at: Optional[datetime] = None
    # dcy-020 / REQ-056: instance_key scopes slots per daemon instance in a
    # shared DB (UNIQUE(instance_key, portfolio_id)); advisory lock is also
    # instance-scoped. retired_at marks a soft-retired / universe-detached slot.
    instance_key: str = "default"
    retired_at: Optional[datetime] = None
    # dcy-022 / REQ-068: execution policy — set on PENDING entry, cleared on exit.
    # timeout_sec: cancel_order is sent after this many seconds of no fill.
    # slippage_pct: effective limit = entry_price * (1 ± pct/100); None = no band.
    timeout_sec: Optional[int] = None
    slippage_pct: Optional[float] = None
    # dcy-028 / REQ-081 (BAT-042): monotonic occupancy counter. Incremented when
    # the slot begins a new occupancy (inactive→pending_buy), stable across one
    # holding episode. Used by the strategy-state CAS to reject writes computed
    # against a prior occupancy of a reused slot (point-ABA guard, dcy-028 R-1).
    occupancy_seq: int = 0
    # Order venue carried from the admitted intent through dispatch/cancel.
    # It is reset to KRX when the permanent asset slot returns to INACTIVE.
    venue: str = "KRX"
    # Immediate cancel-request result. The slot remains pending until fill
    # polling confirms cancelled/filled. Persisted to prevent blind retries
    # across ticks and restarts.
    cancel_state: Optional[str] = None
    cancel_requested_at: Optional[datetime] = None


# Canonical column contract for `Slot` (dcy-001 OQ-2 / FR-5).
# test_contract.py asserts this matches `dataclasses.fields(Slot)` so any
# field add/remove fails loudly. Type mapping lives in the docs (dcy-001 부록 A
# / docs/data-model.md), not here — names/presence only.
EXPECTED_SLOT_FIELDS: frozenset[str] = frozenset({
    "slot_id",
    "status",
    "symbol",
    "qty",
    "avg_price",
    "limit_price",
    "order_id",
    "strategy_id",
    "broker_order_id",
    "portfolio_id",
    "sell_strategy_id",
    "forced_close_at",
    "stop_loss_price",    # REQ-035
    "take_profit_price",  # REQ-035
    "created_at",
    "updated_at",
    "instance_key",       # dcy-020 / REQ-056 (BAT-027)
    "retired_at",         # dcy-020 / REQ-056 (BAT-027)
    "timeout_sec",        # dcy-022 / REQ-068 (BAT-032)
    "slippage_pct",       # dcy-022 / REQ-068 (BAT-032)
    "occupancy_seq",      # dcy-028 / REQ-081 (BAT-042)
    "venue",
    "cancel_state",
    "cancel_requested_at",
})


@dataclass(frozen=True)
class SlotCapacity:
    """Capacity snapshot returned by compute_slot_capacity (REQ-002 AC-6;
    dcy-020/REQ-059 asset-centric redefinition, BAT-030).

    active_count = holding + pending (position-occupying). available_count is
    the remaining admission headroom: max(0, M − active) under a max_active_slots
    cap M, else the inactive (admittable) slot count. total_slots = M when set,
    else the instance's slot count. scarcity_ratio = 1 − available/total.
    """

    inactive_count: int
    holding_count: int
    pending_count: int
    active_count: int
    available_count: int
    total_slots: int
    scarcity_ratio: float


@dataclass(frozen=True)
class SlotTransitionRecord:
    """One append-only row in slot_transition_log (REQ-001, REQ-002)."""

    slot_id: UUID
    from_state: SlotState
    to_state: SlotState
    ts: datetime
    reason: str
    actor: str
    extra: dict = field(default_factory=dict)