from __future__ import annotations
"""삶앎 Stability Engine — health monitoring, auto-recovery, watchdog.

Provides production-grade stability:
  - Health check endpoint with detailed diagnostics
  - Auto-recovery for crashed components (Telegram, WebSocket, Cron)
  - Memory watchdog (prevent runaway memory usage)
  - Session cleanup (stale session garbage collection)
  - Graceful degradation (fallback when components fail)
  - Startup self-test (verify all modules loadable)
  - Error rate tracking (circuit breaker pattern)
"""


import os
try:
    import resource
except ImportError:
    resource = None  # Windows
import threading
import time
import traceback
from collections import deque
from datetime import datetime
from typing import Dict, List, Optional

from .constants import VERSION, KST, BASE_DIR, AUDIT_DB
from .crypto import log

# ── Error tracking ──────────────────────────────────────────

class CircuitBreaker:
    """Track error rates per component. Trip after threshold."""

    def __init__(self, threshold: int = 5, window_sec: int = 300,
                 cooldown_sec: int = 60):
        self.threshold = threshold
        self.window_sec = window_sec
        self.cooldown_sec = cooldown_sec
        self._errors: Dict[str, deque] = {}
        self._tripped: Dict[str, float] = {}  # component -> trip time
        self._lock = threading.Lock()

    def record_error(self, component: str, error: str = ""):
        """Record an error for a component."""
        with self._lock:
            if component not in self._errors:
                self._errors[component] = deque(maxlen=100)
            self._errors[component].append({
                "time": time.time(),
                "error": error[:200],
            })

    def record_success(self, component: str):
        """Record successful operation — helps reset breaker."""
        with self._lock:
            if component in self._tripped:
                elapsed = time.time() - self._tripped[component]
                if elapsed > self.cooldown_sec:
                    del self._tripped[component]
                    log.info(f"🔄 Circuit breaker reset: {component}")

    def is_tripped(self, component: str) -> bool:
        """Check if circuit breaker is open (too many errors)."""
        with self._lock:
            if component in self._tripped:
                if time.time() - self._tripped[component] < self.cooldown_sec:
                    return True
                else:
                    del self._tripped[component]

            errors = self._errors.get(component, deque())
            now = time.time()
            recent = sum(1 for e in errors if now - e["time"] < self.window_sec)

            if recent >= self.threshold:
                self._tripped[component] = now
                log.warning(f"⚡ Circuit breaker tripped: {component} "
                           f"({recent} errors in {self.window_sec}s)")
                return True
            return False

    def get_status(self) -> Dict[str, dict]:
        """Get all component statuses."""
        with self._lock:
            status = {}
            now = time.time()
            for comp, errors in self._errors.items():
                recent = sum(1 for e in errors if now - e["time"] < self.window_sec)
                last_error = errors[-1]["error"] if errors else ""
                status[comp] = {
                    "recent_errors": recent,
                    "total_errors": len(errors),
                    "tripped": comp in self._tripped,
                    "last_error": last_error,
                }
            return status


class HealthMonitor:
    """Comprehensive health monitoring and auto-recovery."""

    def __init__(self):
        self.circuit_breaker = CircuitBreaker()
        self._start_time = time.time()
        self._checks: Dict[str, dict] = {}
        self._recovery_attempts: Dict[str, int] = {}
        self._max_recovery = 3  # Max recovery attempts per component per hour
        self._lock = threading.Lock()

    def check_health(self) -> dict:
        """Run comprehensive health check. Returns health report."""
        report = {
            "status": "healthy",
            "version": VERSION,
            "uptime_seconds": round(time.time() - self._start_time),
            "uptime_human": self._format_uptime(),
            "timestamp": datetime.now(KST).isoformat(),
            "components": {},
            "system": self._check_system(),
            "circuit_breakers": self.circuit_breaker.get_status(),
        }

        # Check each component
        components = {
            "vault": self._check_vault,
            "telegram": self._check_telegram,
            "websocket": self._check_websocket,
            "rag": self._check_rag,
            "mcp": self._check_mcp,
            "cron": self._check_cron,
            "database": self._check_database,
            "llm": self._check_llm,
        }

        unhealthy = 0
        for name, check_fn in components.items():
            try:
                result = check_fn()
                report["components"][name] = result
                if result.get("status") != "ok":
                    unhealthy += 1
            except Exception as e:
                report["components"][name] = {
                    "status": "error",
                    "error": str(e)[:200],
                }
                unhealthy += 1

        if unhealthy > len(components) // 2:
            report["status"] = "critical"
        elif unhealthy > 0:
            report["status"] = "degraded"

        return report

    def _format_uptime(self) -> str:
        secs = int(time.time() - self._start_time)
        hours, remainder = divmod(secs, 3600)
        minutes, seconds = divmod(remainder, 60)
        if hours > 24:
            days = hours // 24
            hours = hours % 24
            return f"{days}d {hours}h {minutes}m"
        return f"{hours}h {minutes}m {seconds}s"

    def _check_system(self) -> dict:
        """Check system resources."""
        info = {}
        try:
            if resource is None:
                raise OSError("resource module unavailable")
            usage = resource.getrusage(resource.RUSAGE_SELF)
            info["memory_mb"] = round(usage.ru_maxrss / 1024, 1)  # Linux: KB
            info["user_time"] = round(usage.ru_utime, 2)
            info["sys_time"] = round(usage.ru_stime, 2)
        except Exception:
            pass

        try:
            # Check disk space for workspace
            stat = os.statvfs(str(BASE_DIR))
            info["disk_free_mb"] = round(stat.f_bavail * stat.f_frsize / (1024 * 1024), 1)
            info["disk_total_mb"] = round(stat.f_blocks * stat.f_frsize / (1024 * 1024), 1)
            info["disk_pct"] = round(100 * (1 - stat.f_bavail / stat.f_blocks), 1)
        except Exception:
            pass

        try:
            info["pid"] = os.getpid()
            info["threads"] = threading.active_count()
        except Exception:
            pass

        return info

    def _check_vault(self) -> dict:
        from .crypto import vault
        return {
            "status": "ok" if vault.is_unlocked else "locked",
            "locked": not vault.is_unlocked,
        }

    def _check_telegram(self) -> dict:
        try:
            from .core import _tg_bot
            if _tg_bot and _tg_bot.token:
                return {"status": "ok", "running": True,
                        "owner": bool(_tg_bot.owner_id)}
            return {"status": "not_configured"}
        except Exception as e:
            return {"status": "error", "error": str(e)[:100]}

    def _check_websocket(self) -> dict:
        try:
            from .ws import ws_server
            return {
                "status": "ok" if ws_server._running else "stopped",
                "running": ws_server._running,
                "clients": ws_server.client_count,
                "port": ws_server.port,
            }
        except Exception as e:
            return {"status": "error", "error": str(e)[:100]}

    def _check_rag(self) -> dict:
        try:
            from .rag import rag_engine
            stats = rag_engine.get_stats()
            return {
                "status": "ok" if stats["total_chunks"] > 0 else "empty",
                **stats,
            }
        except Exception as e:
            return {"status": "error", "error": str(e)[:100]}

    def _check_mcp(self) -> dict:
        try:
            from .mcp import mcp_manager
            servers = mcp_manager.list_servers()
            connected = sum(1 for s in servers if s.get("connected"))
            return {
                "status": "ok",
                "total_servers": len(servers),
                "connected": connected,
                "total_tools": sum(s.get("tools", 0) for s in servers),
            }
        except Exception as e:
            return {"status": "error", "error": str(e)[:100]}

    def _check_cron(self) -> dict:
        try:
            from .core import cron
            return {
                "status": "ok" if cron._running else "stopped",
                "running": cron._running,
                "jobs": len(cron.jobs),
            }
        except Exception as e:
            return {"status": "error", "error": str(e)[:100]}

    def _check_database(self) -> dict:
        import sqlite3
        try:
            conn = sqlite3.connect(str(AUDIT_DB))
            count = conn.execute("SELECT COUNT(*) FROM audit_log").fetchone()[0]
            usage_count = conn.execute("SELECT COUNT(*) FROM usage_stats").fetchone()[0]
            conn.close()
            size_kb = round(AUDIT_DB.stat().st_size / 1024, 1) if AUDIT_DB.exists() else 0
            return {
                "status": "ok",
                "audit_entries": count,
                "usage_entries": usage_count,
                "size_kb": size_kb,
            }
        except Exception as e:
            return {"status": "error", "error": str(e)[:100]}

    def _check_llm(self) -> dict:
        """Check LLM availability (based on circuit breaker, not actual API call)."""
        breaker_status = self.circuit_breaker.get_status()
        llm_status = breaker_status.get("llm", {})
        if llm_status.get("tripped"):
            return {
                "status": "degraded",
                "tripped": True,
                "recent_errors": llm_status.get("recent_errors", 0),
                "last_error": llm_status.get("last_error", ""),
            }
        return {"status": "ok", "tripped": False}

    async def auto_recover(self):
        """Attempt to recover crashed components."""
        health = self.check_health()
        recovered = []

        for comp, status in health["components"].items():
            if status.get("status") in ("ok", "not_configured", "locked"):
                continue

            # Check recovery budget
            hour_key = f"{comp}_{int(time.time() // 3600)}"
            attempts = self._recovery_attempts.get(hour_key, 0)
            if attempts >= self._max_recovery:
                log.warning(f"🔧 Recovery budget exhausted: {comp} ({attempts} attempts this hour)")
                continue

            self._recovery_attempts[hour_key] = attempts + 1

            try:
                if comp == "websocket":
                    from .ws import ws_server
                    if not ws_server._running:
                        await ws_server.start()
                        recovered.append(comp)
                        log.info(f"🔧 Auto-recovered: {comp}")

                elif comp == "rag" and status.get("status") == "empty":
                    from .rag import rag_engine
                    rag_engine.reindex(force=True)
                    recovered.append(comp)
                    log.info(f"🔧 Auto-recovered: {comp}")

                elif comp == "cron":
                    from .core import cron
                    if not cron._running:
                        import asyncio
                        asyncio.create_task(cron.run())
                        recovered.append(comp)
                        log.info(f"🔧 Auto-recovered: {comp}")

            except Exception as e:
                log.error(f"🔧 Recovery failed ({comp}): {e}")
                self.circuit_breaker.record_error(f"recovery_{comp}", str(e))

        return recovered

    def startup_selftest(self) -> dict:
        """Run self-test on startup to verify all modules."""
        results = {}
        modules = [
            ("constants", "salmalm.constants"),
            ("crypto", "salmalm.crypto"),
            ("core", "salmalm.core"),
            ("llm", "salmalm.llm"),
            ("tools", "salmalm.tools"),
            ("prompt", "salmalm.prompt"),
            ("engine", "salmalm.engine"),
            ("telegram", "salmalm.telegram"),
            ("web", "salmalm.web"),
            ("ws", "salmalm.ws"),
            ("rag", "salmalm.rag"),
            ("mcp", "salmalm.mcp"),
            ("browser", "salmalm.browser"),
            ("nodes", "salmalm.nodes"),
            ("auth", "salmalm.auth"),
            ("tls", "salmalm.tls"),
            ("logging_ext", "salmalm.logging_ext"),
            ("docs", "salmalm.docs"),
        ]

        passed = 0
        for name, module_path in modules:
            try:
                __import__(module_path)
                results[name] = "ok"
                passed += 1
            except Exception as e:
                results[name] = f"FAIL: {e}"
                log.error(f"Self-test FAIL: {name} — {e}")

        total = len(modules)
        log.info(f"🧪 Self-test: {passed}/{total} modules OK")
        return {
            "passed": passed,
            "total": total,
            "all_ok": passed == total,
            "modules": results,
        }


# ── Watchdog async task ──────────────────────────────────────

async def watchdog_tick(monitor: HealthMonitor):
    """Periodic watchdog check — run via cron every 5 minutes."""
    health = monitor.check_health()

    # Log warnings for degraded components
    if health["status"] != "healthy":
        degraded = [name for name, s in health["components"].items()
                    if s.get("status") not in ("ok", "not_configured", "locked")]
        if degraded:
            log.warning(f"⚠️ Degraded components: {', '.join(degraded)}")

    # Memory check — warn if > 500MB
    mem_mb = health.get("system", {}).get("memory_mb", 0)
    if mem_mb > 500:
        log.warning(f"⚠️ High memory usage: {mem_mb}MB")

    # Disk check — warn if < 500MB free
    disk_free = health.get("system", {}).get("disk_free_mb", 9999)
    if disk_free < 500:
        log.warning(f"⚠️ Low disk space: {disk_free}MB free")

    # Auto-recover if needed
    if health["status"] in ("degraded", "critical"):
        recovered = await monitor.auto_recover()
        if recovered:
            log.info(f"🔧 Auto-recovered: {', '.join(recovered)}")


# Module-level instance
health_monitor = HealthMonitor()
