"""
AWOOOI AIOps Phase 1 — 執行後驗證器
=====================================
每次 AI 修復動作執行後，主動用 MCP 抓取環境後狀態，
與 EvidenceSnapshot.pre_execution_state 對比，
判斷修復是否真的有效。

驗證結果三態：
  - "success"   — 問題已解決（Pod Running / 指標恢復正常）
  - "degraded"  — 部分改善但未完全恢復
  - "failed"    — 執行後狀態比執行前更差，或完全未改善
  - "timeout"   — 驗證超時（MCP 無法回應）

驗證結果用途：
  1. 填入 EvidenceSnapshot.verification_result（Phase 3 學習閉環基礎）
  2. 傳給 learning_service 更新 Playbook EWMA trust_score
  3. 觸發 Reviewer Agent 的 rollback 決策（Phase 2）

設計原則：
  - 執行後等待 warm-up period（預設 10s），讓 K8s controller 有時間收斂
  - 超時不 raise，標記 "timeout" 並繼續流程
  - 不阻塞原始執行路徑（await，但結果不影響執行本身是否成功）

ADR-081: PreDecisionInvestigator + EvidenceSnapshot
MASTER §3.1 L6×D1
2026-04-15 ogt + Claude Sonnet 4.6 (亞太): Phase 1 初始建立
"""

from __future__ import annotations

import asyncio
import time
from typing import TYPE_CHECKING, Any

import structlog

from src.services.evidence_snapshot import EvidenceSnapshot
from src.services.mcp_tool_registry import SensorDimension, get_mcp_tool_registry
from src.services.sanitization_service import sanitize_dict_values

if TYPE_CHECKING:
    from src.models.incident import Incident

logger = structlog.get_logger(__name__)

# 執行後等待收斂時間（秒）— K8s controller 需要時間處理重啟/滾動更新
POST_EXEC_WARMUP_SEC = 10.0

# 驗證超時（秒）
VERIFY_TIMEOUT_SEC = 30.0

# MCP 單工具超時（秒）
TOOL_TIMEOUT_SEC = 8.0


class PostExecutionVerifier:
    """
    執行後環境狀態驗證器。

    在 approval_execution.py 的 execute_approved_action() 中，
    執行動作後呼叫 verify()，取得驗證結果並補填 EvidenceSnapshot。

    Usage:
        verifier = get_post_execution_verifier()
        result = await verifier.verify(
            incident=incident,
            snapshot=pre_decision_snapshot,
            action_taken="restart_service:awoooi-api",
        )
        # result: "success" | "degraded" | "failed" | "timeout"
    """

    def __init__(self) -> None:
        self._registry = get_mcp_tool_registry()

    async def verify(
        self,
        incident: "Incident",
        snapshot: EvidenceSnapshot | None,
        action_taken: str,
        warmup_sec: float = POST_EXEC_WARMUP_SEC,
    ) -> str:
        """
        執行後驗證。

        Args:
            incident: 原始 Incident（用於取 labels 定位資源）
            snapshot: 執行前的 EvidenceSnapshot（取 pre_execution_state 作基準線）
            action_taken: 執行的動作描述（例如 "restart_service:awoooi-api"）
            warmup_sec: 等待 K8s 收斂的秒數

        Returns:
            str: "success" | "degraded" | "failed" | "timeout"
        """
        incident_id = _get_incident_id(incident)

        logger.info(
            "verifier_start",
            incident_id=incident_id,
            action=action_taken,
            warmup_sec=warmup_sec,
        )

        # 1. 等待收斂
        if warmup_sec > 0:
            await asyncio.sleep(warmup_sec)

        # 2. 抓後狀態
        try:
            post_state = await asyncio.wait_for(
                self._collect_post_state(incident),
                timeout=VERIFY_TIMEOUT_SEC,
            )
        except asyncio.TimeoutError:
            logger.warning("verifier_timeout", incident_id=incident_id)
            if snapshot:
                await _update_snapshot(snapshot, {}, "timeout")
            return "timeout"
        except Exception:
            logger.exception("verifier_collect_error", incident_id=incident_id)
            if snapshot:
                await _update_snapshot(snapshot, {}, "failed")
            return "failed"

        # 3. 對比前後狀態
        pre_state = snapshot.pre_execution_state if snapshot else None
        result = _assess_recovery(pre_state, post_state, action_taken)

        # 4. 更新 EvidenceSnapshot
        if snapshot:
            await _update_snapshot(snapshot, post_state, result)

        logger.info(
            "verifier_done",
            incident_id=incident_id,
            result=result,
            action=action_taken,
        )
        return result

    async def capture_pre_execution_state(
        self,
        incident: "Incident",
        snapshot: EvidenceSnapshot,
    ) -> None:
        """
        執行前快照當前狀態，寫入 snapshot.pre_execution_state。

        在 approval_execution.py 的動作執行「之前」呼叫。
        """
        incident_id = _get_incident_id(incident)
        try:
            state = await asyncio.wait_for(
                self._collect_post_state(incident),  # 同樣的抓取邏輯
                timeout=TOOL_TIMEOUT_SEC,
            )
            snapshot.pre_execution_state = state
            logger.debug("verifier_pre_state_captured", incident_id=incident_id)
        except Exception:
            logger.warning("verifier_pre_state_failed", incident_id=incident_id)
            snapshot.pre_execution_state = {}

    async def _collect_post_state(self, incident: "Incident") -> dict[str, Any]:
        """
        蒐集執行後環境狀態（K8s Pod 狀態 + 關鍵指標）。

        只選 D1（K8s 狀態）和 D3（指標）作為驗證基準線，
        其他感官維度（日誌、拓撲等）在驗證時不必要。
        """
        state: dict[str, Any] = {}
        alertname = _get_alertname(incident)
        labels = _get_labels(incident)

        # 取 D1 + D3 工具
        all_tools = self._registry.suggest_tools(alertname=alertname, incident_labels=labels)
        verify_tools = [
            t for t in all_tools
            if any(d in (SensorDimension.D1_K8S_STATE, SensorDimension.D3_METRICS)
                   for d in t.dimensions)
        ]

        params = {
            "namespace": labels.get("namespace", "awoooi-prod"),
            "pod_name": labels.get("pod", labels.get("name", "")),
            "deployment": labels.get("deployment", ""),
            "host": labels.get("instance", "").split(":")[0] or labels.get("host", ""),
        }

        async def _call_one(reg) -> tuple[str, Any]:
            try:
                result = await asyncio.wait_for(
                    reg.provider.execute(reg.tool.name, params),
                    timeout=TOOL_TIMEOUT_SEC,
                )
                if result.success and result.output:
                    return reg.tool.name, result.output
            except Exception:
                pass
            return reg.tool.name, None

        results = await asyncio.gather(*[_call_one(t) for t in verify_tools])
        for tool_name, output in results:
            if output is not None:
                if isinstance(output, dict):
                    state[tool_name] = sanitize_dict_values(output, f"post_state.{tool_name}")
                else:
                    state[tool_name] = {"raw": sanitize(str(output), f"post_state.{tool_name}")}

        return state


# ─────────────────────────────────────────────────────────────────────────────
# Recovery Assessment
# ─────────────────────────────────────────────────────────────────────────────

def _assess_recovery(
    pre_state: dict[str, Any] | None,
    post_state: dict[str, Any],
    action_taken: str,
) -> str:
    """
    評估修復效果。

    Phase 1 使用啟發式規則（基於 K8s Pod 狀態字串判斷）。
    Phase 4 將改用動態基線（Holt-Winters 偏差量），不再用靜態閾值。

    Heuristics（Phase 1 版本）：
    - post_state 含 Running → success
    - post_state 含 CrashLoopBackOff / Error / OOMKilled → failed
    - post_state 為空（MCP 無回應）→ degraded
    - pre_state 與 post_state 完全相同 → degraded（未改變）
    """
    if not post_state:
        return "degraded"

    # 轉為字串做啟發式掃描
    post_str = str(post_state).lower()
    pre_str = str(pre_state).lower() if pre_state else ""

    # 失敗信號（Gate 1 fix: 移除裸 "error" — 會誤觸 error_rate/error_count 等指標 key）
    # "error" 作為 K8s ContainerState reason 由 "failed" Pod phase 間接覆蓋
    failure_signals = ["crashloopbackoff", "oomkilled", "oomkill", "failed"]
    if any(sig in post_str for sig in failure_signals):
        return "failed"

    # 成功信號
    success_signals = ["running", "ready", "1/1", "2/2", "3/3", "healthy"]
    if any(sig in post_str for sig in success_signals):
        # 但如果 pre_state 已經是 running，可能是無效操作
        if pre_str and any(sig in pre_str for sig in success_signals):
            # 如果執行的是 restart，即使 pre/post 都 Running 也算 success
            if "restart" in action_taken.lower() or "delete" in action_taken.lower():
                return "success"
            return "degraded"
        return "success"

    # 前後無變化
    if pre_str and post_str == pre_str:
        return "degraded"

    return "degraded"


# ─────────────────────────────────────────────────────────────────────────────
# Helpers
# ─────────────────────────────────────────────────────────────────────────────

def _get_incident_id(incident: "Incident") -> str:
    return incident.incident_id if hasattr(incident, "incident_id") else str(incident.id)


def _get_alertname(incident: "Incident") -> str:
    if incident.signals:
        return incident.signals[0].labels.get("alertname", "")
    return ""


def _get_labels(incident: "Incident") -> dict[str, Any]:
    if incident.signals:
        return incident.signals[0].labels
    return {}


async def _update_snapshot(
    snapshot: EvidenceSnapshot,
    post_state: dict[str, Any],
    result: str,
) -> None:
    """補填 EvidenceSnapshot 的 post_execution_state + verification_result。"""
    try:
        await snapshot.update_post_execution(post_state, result)
    except Exception:
        logger.exception("verifier_snapshot_update_failed", snapshot_id=snapshot.snapshot_id)


# ─────────────────────────────────────────────────────────────────────────────
# Singleton
# ─────────────────────────────────────────────────────────────────────────────

_verifier: PostExecutionVerifier | None = None


def get_post_execution_verifier() -> PostExecutionVerifier:
    """取得 PostExecutionVerifier Singleton。"""
    global _verifier
    if _verifier is None:
        _verifier = PostExecutionVerifier()
    return _verifier