from __future__ import annotations

import json
import time
from pathlib import Path
from typing import Dict, Any, Optional


def _utc():
    return time.strftime("%Y-%m-%dT%H:%M:%SZ", time.gmtime())


class SovereignFreezeReview:
    """
    Bank-grade freeze lifecycle manager

    Handles:
    - review
    - approve (release)
    - reject (block)
    """

    def __init__(self, freeze_dir: str = ".sovereign_runtime/freezes"):
        self.freeze_dir = Path(freeze_dir)
        self.freeze_dir.mkdir(parents=True, exist_ok=True)

    def _path(self, freeze_id: str) -> Path:
        return self.freeze_dir / f"{freeze_id}.json"

    def load(self, freeze_id: str) -> Dict[str, Any]:
        path = self._path(freeze_id)
        if not path.exists():
            raise FileNotFoundError(f"Freeze not found: {freeze_id}")

        return json.loads(path.read_text())

    def save(self, freeze_id: str, data: Dict[str, Any]):
        path = self._path(freeze_id)
        path.write_text(json.dumps(data, indent=2))

    # ---------------------------------------------------------
    # REVIEW (read-only)
    # ---------------------------------------------------------
    def review(self, freeze_id: str) -> Dict[str, Any]:
        data = self.load(freeze_id)

        return {
            "freeze_id": freeze_id,
            "status": data.get("status"),
            "reason": data.get("reason"),
            "risk_score": data.get("decision_payload", {}).get("risk_score"),
            "policy": data.get("decision_payload", {}).get("policy_id"),
            "created_at": data.get("created_at"),
            "request": data.get("request_payload"),
        }

    # ---------------------------------------------------------
    # RELEASE (approve execution)
    # ---------------------------------------------------------
    def release(
        self,
        freeze_id: str,
        reviewer: str,
        reason: str
    ) -> Dict[str, Any]:

        data = self.load(freeze_id)

        if data.get("status") != "FROZEN":
            raise Exception("Freeze is not active")

        data["status"] = "RELEASED"
        data["released_at"] = _utc()
        data["released_by"] = reviewer
        data["release_reason"] = reason

        self.save(freeze_id, data)

        return {
            "status": "RELEASED",
            "freeze_id": freeze_id,
            "released_by": reviewer
        }

    # ---------------------------------------------------------
    # ESCALATE → BLOCK
    # ---------------------------------------------------------
    def block(
        self,
        freeze_id: str,
        reviewer: str,
        reason: str
    ) -> Dict[str, Any]:

        data = self.load(freeze_id)

        if data.get("status") != "FROZEN":
            raise Exception("Freeze is not active")

        data["status"] = "BLOCKED"
        data["blocked_at"] = _utc()
        data["blocked_by"] = reviewer
        data["block_reason"] = reason

        self.save(freeze_id, data)

        return {
            "status": "BLOCKED",
            "freeze_id": freeze_id,
            "blocked_by": reviewer
        }


# ---------------------------------------------------------
# test
# ---------------------------------------------------------
if __name__ == "__main__":
    fr = SovereignFreezeReview()

    # Example usage:
    # assumes freeze file already exists

    try:
        fz = fr.review("frz_test")
        print("REVIEW:", json.dumps(fz, indent=2))
    except:
        print("No test freeze found")