from contextlib import asynccontextmanager
from datetime import datetime
import asyncio
from fastapi import FastAPI, WebSocket, WebSocketDisconnect
from fastapi.middleware.cors import CORSMiddleware
from sqlalchemy import select

from app.core.config import settings
from app.core.database import init_db, AsyncSessionLocal
from app.core.security import get_password_hash
from app.models.models import User
from app.api.auth import router as auth_router
from app.api.clients import router as clients_router
from app.api.jobs import router as jobs_router
from app.api.upload import router as upload_router
from app.api.backups import router as backups_router
from app.api.events import router as events_router
from app.api.stats import router as stats_router
from app.api.settings import router as settings_router
from app.api.users import router as users_router
from app.api.script_jobs import router as script_jobs_router
from app.ws.manager import ws_manager

async def script_scheduler_daemon():
    """
    Background daemon that runs every minute to execute scheduled script jobs.
    """
    from app.models.models import ScriptJob
    from app.api.script_jobs import execute_script_in_background
    from app.core.database import AsyncSessionLocal
    from sqlalchemy import select
    
    print("[*] Script Scheduler Daemon started.")
    
    def match_cron(cron_expr: str, dt: datetime) -> bool:
        try:
            fields = cron_expr.strip().split()
            if len(fields) < 5:
                return False
            minute, hour, dom, month, dow = fields
            
            def match_field(val: int, field: str, dow_check=False) -> bool:
                if field == '*':
                    return True
                if '/' in field:
                    base, step = field.split('/')
                    step = int(step)
                    if base == '*':
                        return val % step == 0
                    return (val - int(base)) % step == 0
                if ',' in field:
                    parts = field.split(',')
                    return any(match_field(val, p, dow_check) for p in parts)
                if '-' in field:
                    start, end = map(int, field.split('-'))
                    return start <= val <= end
                if dow_check:
                    cron_dow = (dt.weekday() + 1) % 7
                    if int(field) == 7 and cron_dow == 0:
                        return True
                    return cron_dow == int(field)
                return val == int(field)
                
            return (
                match_field(dt.minute, minute) and
                match_field(dt.hour, hour) and
                match_field(dt.day, dom) and
                match_field(dt.month, month) and
                match_field(dt.weekday(), dow, dow_check=True)
            )
        except Exception:
            return False

    while True:
        try:
            now_sec = datetime.now().second
            sleep_time = 60 - now_sec
            await asyncio.sleep(sleep_time)
            
            now = datetime.now()
            async with AsyncSessionLocal() as db:
                result = await db.execute(select(ScriptJob).where(ScriptJob.is_active == True))
                jobs = result.scalars().all()
                
                for job in jobs:
                    if match_cron(job.schedule_cron, now):
                        print(f"[*] Scheduler: Script Job '{job.name}' is due. Triggering execution...")
                        asyncio.create_task(execute_script_in_background(job.id))
                        
        except asyncio.CancelledError:
            break
        except Exception as e:
            print(f"[!] Scheduler error: {e}")
            await asyncio.sleep(5)

@asynccontextmanager
async def lifespan(app: FastAPI):
    # Initialize database tables
    await init_db()
    
    # Start scheduler daemon task
    scheduler_task = asyncio.create_task(script_scheduler_daemon())

    # Seed default administrator and initialize settings
    async with AsyncSessionLocal() as session:
        # Load and apply settings to storage_provider
        from app.services.settings_service import get_all_settings
        settings_dict = await get_all_settings(session)
        
        # Apply storage_root
        from app.storage.local import storage_provider
        from pathlib import Path
        import os
        storage_root = settings_dict.get("storage_root")
        if storage_root:
            path = Path(storage_root).resolve()
            os.makedirs(path, exist_ok=True)
            storage_provider.root_dir = path

        result = await session.execute(select(User).where(User.email == "admin@oneverdrive.local"))
        admin = result.scalar_one_or_none()
        if not admin:
            admin_user = User(
                email="admin@oneverdrive.local",
                hashed_password=get_password_hash("Admin1234!"),
                full_name="System Administrator",
                role="ADMIN",
                is_active=True
            )
            session.add(admin_user)
            await session.commit()
            print(">> [OnEver Drive] Default admin created: admin@oneverdrive.local / Admin1234!")
        else:
            admin.hashed_password = get_password_hash("Admin1234!")
            admin.is_active = True
            session.add(admin)
            await session.commit()
            print(">> [OnEver Drive] Default admin verified & password reset to: Admin1234!")

    try:
        yield
    finally:
        scheduler_task.cancel()
        try:
            await scheduler_task
        except asyncio.CancelledError:
            pass
        print("[*] Script Scheduler Daemon stopped.")

app = FastAPI(
    title=settings.PROJECT_NAME,
    version=settings.VERSION,
    description="Centralized Backup & Sync Platform for Windows on Proxmox VE",
    lifespan=lifespan
)

# CORS Middleware to allow Web UI connections
app.add_middleware(
    CORSMiddleware,
    allow_origins=["*"],
    allow_credentials=True,
    allow_methods=["*"],
    allow_headers=["*"],
)

# Register API Routers
app.include_router(auth_router, prefix=settings.API_V1_PREFIX)
app.include_router(clients_router, prefix=settings.API_V1_PREFIX)
app.include_router(jobs_router, prefix=settings.API_V1_PREFIX)
app.include_router(upload_router, prefix=settings.API_V1_PREFIX)
app.include_router(backups_router, prefix=settings.API_V1_PREFIX)
app.include_router(events_router, prefix=settings.API_V1_PREFIX)
app.include_router(stats_router, prefix=settings.API_V1_PREFIX)
app.include_router(settings_router, prefix=settings.API_V1_PREFIX)
app.include_router(users_router, prefix=settings.API_V1_PREFIX)
app.include_router(script_jobs_router, prefix=settings.API_V1_PREFIX)

@app.websocket("/ws/telemetry")
async def websocket_telemetry(websocket: WebSocket):
    """WebSocket endpoint for real-time dashboard telemetry and live upload meters."""
    await ws_manager.connect(websocket)
    try:
        while True:
            # Keep connection open and accept incoming ping/pong or messages
            data = await websocket.receive_text()
            if data == "ping":
                await websocket.send_text("pong")
    except WebSocketDisconnect:
        ws_manager.disconnect(websocket)
    except Exception:
        ws_manager.disconnect(websocket)

@app.get("/health")
async def health():
    return {
        "status": "healthy",
        "service": settings.PROJECT_NAME,
        "version": settings.VERSION
    }