"""Resource envelope accounting: one envelope per run, shared by executor, gate cycles and reviewer sessions."""
from __future__ import annotations
from dataclasses import dataclass, field

@dataclass
class Envelope:
    max_budget_usd: float
    wall_seconds: int
    max_turns_per_session: int
    spent_usd: float = 0.0
    spent_wall_s: float = 0.0
    sessions: list = field(default_factory=list)   # [{"session_id","role","cost","wall_s","turns"}]
    min_continuation_usd: float = 0.25

    def remaining_usd(self) -> float:
        return max(0.0, self.max_budget_usd - self.spent_usd)

    def remaining_wall(self) -> int:
        return int(max(0, self.wall_seconds - self.spent_wall_s))

    def can_continue(self, min_wall_s: int = 120) -> bool:
        return self.remaining_usd() >= self.min_continuation_usd and self.remaining_wall() >= min_wall_s

    def charge(self, session_id: str, role: str, cost: float, wall_s: float, turns: int | None):
        cost = float(cost or 0.0)
        self.spent_usd += cost; self.spent_wall_s += float(wall_s or 0.0)
        self.sessions.append({"session_id": session_id, "role": role, "cost_usd": cost, "wall_s": wall_s, "turns": turns})

    def summary(self) -> dict:
        return {"max_budget_usd": self.max_budget_usd, "wall_seconds": self.wall_seconds, "max_turns_per_session": self.max_turns_per_session,
                "spent_usd": round(self.spent_usd, 6), "spent_wall_s": round(self.spent_wall_s, 1),
                "executor_usd": round(sum(s["cost_usd"] for s in self.sessions if s["role"] == "executor"), 6),
                "reviewer_usd": round(sum(s["cost_usd"] for s in self.sessions if s["role"] == "reviewer"), 6),
                "n_sessions": len(self.sessions), "sessions": self.sessions}