"""Bark selection with phase cooldown (design R5/R11)."""
from __future__ import annotations

import random
from typing import Dict, List, Optional, Set, Tuple

class BarkSelector:
    def __init__(self, rng: Optional[random.Random] = None):
        self.rng = rng or random.Random()
        # (npc_id, phase) -> used bark ids this phase instance
        self._used: Dict[Tuple[str, str], Set[str]] = {}

    def reset_phase(self, phase: str) -> None:
        keys = [k for k in self._used if k[1] == phase]
        for k in keys:
            del self._used[k]

    def pick(self, npc_id: str, phase: str, barks: List[dict]) -> Optional[str]:
        if not barks:
            return None
        key = (npc_id, phase)
        used = self._used.setdefault(key, set())
        candidates = []
        for b in barks:
            bid = b.get("id") or b.get("text")
            bphase = b.get("phase")
            if bid in used:
                continue
            if bphase and bphase != phase:
                continue
            candidates.append(b)
        if not candidates:
            # allow phase-agnostic leftovers
            candidates = [b for b in barks if (b.get("id") or b.get("text")) not in used]
        if not candidates:
            return None
        choice = self.rng.choice(candidates)
        bid = choice.get("id") or choice.get("text")
        used.add(bid)
        return choice.get("text")
# reseal-product R387