import asyncio
import json
import logging
import socket
from typing import List, Optional
from datetime import datetime, timezone

from fastapi import APIRouter, Depends, HTTPException, WebSocket, WebSocketDisconnect, Request
from fastapi.responses import HTMLResponse
from sqlalchemy.orm import Session
from database import get_db
from models import Device, VitalReading, TransmissionLog

logger = logging.getLogger(__name__)
router = APIRouter()

# === WebSocket Manager for real-time vitals push ===
class VitalsWebSocketManager:
    """Manages WebSocket connections for live vitals streaming."""

    def __init__(self):
        self.active_connections: List[WebSocket] = []

    async def connect(self, websocket: WebSocket):
        await websocket.accept()
        self.active_connections.append(websocket)
        logger.info(f"WebSocket client connected ({len(self.active_connections)} active)")

    def disconnect(self, websocket: WebSocket):
        if websocket in self.active_connections:
            self.active_connections.remove(websocket)
        logger.info(f"WebSocket client disconnected ({len(self.active_connections)} active)")

    async def broadcast_vitals(self, vitals_data: dict):
        """Send vitals to all connected WebSocket clients."""
        dead = []
        for connection in self.active_connections:
            try:
                await connection.send_json(vitals_data)
            except Exception:
                dead.append(connection)
        for d in dead:
            self.disconnect(d)


# Global singleton
ws_manager = VitalsWebSocketManager()


def get_ws_manager() -> VitalsWebSocketManager:
    return ws_manager


# === Dashboard HTML Route ===
@router.get("/dashboard", response_class=HTMLResponse)
def serve_dashboard():
    """Serve the vitals monitoring dashboard."""
    import os
    dashboard_path = os.path.join(os.path.dirname(os.path.dirname(__file__)), "static", "dashboard.html")
    try:
        with open(dashboard_path, "r", encoding="utf-8") as f:
            return HTMLResponse(content=f.read())
    except FileNotFoundError:
        return HTMLResponse(content="<h1>Dashboard not found</h1><p>static/dashboard.html is missing</p>", status_code=404)


# === API Endpoints ===
@router.get("/health")
def health_check():
    return {"status": "ok", "service": "Patient Monitor Vital Signs Forwarder"}

@router.get("/status")
def get_system_status(request: Request, db: Session = Depends(get_db)):
    total_devices = db.query(Device).count()
    active_devices = db.query(Device).filter(Device.status == "active").count()
    total_readings = db.query(VitalReading).count()
    pending_transmissions = db.query(VitalReading).filter(VitalReading.transmitted == False).count()
    active_ports = getattr(request.app.state, "active_ports", [])
    
    return {
        "total_devices": total_devices,
        "active_devices": active_devices,
        "total_readings_stored": total_readings,
        "pending_transmissions": pending_transmissions,
        "active_ports": active_ports
    }

@router.get("/devices")
def list_devices(db: Session = Depends(get_db)):
    devices = db.query(Device).all()
    now = datetime.now(timezone.utc)
    updated = False
    for device in devices:
        last_seen = device.last_seen
        if last_seen.tzinfo is None:
            last_seen = last_seen.replace(tzinfo=timezone.utc)
        
        # If not seen for more than 15 seconds, mark offline
        if (now - last_seen).total_seconds() > 15.0:
            if device.status != "offline":
                device.status = "offline"
                updated = True
        else:
            if device.status != "active":
                device.status = "active"
                updated = True
    if updated:
        db.commit()
    return devices

@router.get("/latest-readings")
def get_latest_readings(device_id: str = None, limit: int = 10, db: Session = Depends(get_db)):
    query = db.query(VitalReading)
    if device_id:
        query = query.filter(VitalReading.device_id == device_id)
    readings = query.order_by(VitalReading.timestamp.desc()).limit(limit).all()
    return readings

@router.get("/readings")
def get_readings(device_id: str = None, patient_id: str = None, limit: int = 50, db: Session = Depends(get_db)):
    query = db.query(VitalReading)
    if device_id:
        query = query.filter(VitalReading.device_id == device_id)
    if patient_id:
        query = query.filter(VitalReading.patient_id == patient_id)
    
    return query.order_by(VitalReading.timestamp.desc()).limit(limit).all()

@router.get("/transmission-logs")
def get_transmission_logs(limit: int = 50, db: Session = Depends(get_db)):
    logs = db.query(TransmissionLog).order_by(TransmissionLog.timestamp.desc()).limit(limit).all()
    return logs

@router.post("/test-api")
def test_target_api_connection():
    """
    Endpoint to trigger a test POST to the target API.
    """
    from config import settings
    return {
        "message": "Test triggered",
        "target_url": settings.target_api_url
    }


@router.get("/network-info")
def get_network_info():
    """
    Returns this PC's local IP addresses.
    Useful for configuring the CMS7000PLUS monitor's CMS Server IP.
    """
    from config import settings
    ips = []
    try:
        for info in socket.getaddrinfo(socket.gethostname(), None, socket.AF_INET):
            ip = info[4][0]
            if ip not in ips and not ip.startswith('127.'):
                ips.append(ip)
    except Exception:
        pass
    # Find primary IP
    primary_ip = None
    try:
        s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
        s.connect(('8.8.8.8', 80))
        primary_ip = s.getsockname()[0]
        s.close()
        if primary_ip not in ips:
            ips.insert(0, primary_ip)
    except Exception:
        pass
    
    return {
        "hostname": socket.gethostname(),
        "ip_addresses": ips,
        "primary_ip": primary_ip or (ips[0] if ips else None),
        "monitor_model": settings.monitor_model,
        "contec_ports": settings.contec_ports,
        "instructions": [
            f"1. Connect your {settings.monitor_model} to this PC via Ethernet",
            f"2. On the monitor: System Setup → Network → CMS Settings",
            f"3. Set Server IP to: {primary_ip or 'your PC IP'}",
            f"4. Set Server Port to: {settings.contec_ports[0] if settings.contec_ports else 511}",
            f"5. Enable the CMS connection",
            f"6. The dashboard will show data automatically"
        ]
    }


# === Push Vitals Endpoint (for local-to-cloud sync) ===
from schemas import NormalizedVitals
from models import Patient


@router.post("/push-vitals")
async def push_vitals(vitals: NormalizedVitals, api_key: str = None, db: Session = Depends(get_db)):
    """
    Receive vitals pushed from a local instance and store + broadcast them.
    
    This enables the 'split architecture' where:
    - Local instance receives data from physical monitors via TCP
    - Local instance POSTs vitals here for cloud storage & dashboard access
    
    Optional: pass ?api_key=YOUR_KEY for basic authentication.
    """
    from config import settings
    
    # Optional API key check
    if settings.api_token and api_key != settings.api_token:
        if settings.api_token:  # Only enforce if a token is configured
            raise HTTPException(status_code=401, detail="Invalid or missing api_key")
    
    try:
        # 1. Device tracking
        device = db.query(Device).filter(Device.device_id == vitals.device_id).first()
        if not device:
            device = Device(
                device_id=vitals.device_id,
                ip_address=vitals.ip_address or "remote-push",
                status="active"
            )
            db.add(device)
        else:
            if vitals.ip_address:
                device.ip_address = vitals.ip_address
            device.status = "active"
            device.last_seen = datetime.now(timezone.utc)
        
        # 2. Patient tracking
        from models import VitalReading as VR
        if vitals.patient_id == "UNKNOWN":
            last_known_reading = (
                db.query(VR)
                .filter(VR.device_id == vitals.device_id)
                .filter(VR.patient_id != "UNKNOWN")
                .order_by(VR.timestamp.desc())
                .first()
            )
            if last_known_reading:
                vitals.patient_id = last_known_reading.patient_id

        patient = db.query(Patient).filter(Patient.patient_id == vitals.patient_id).first()
        if not patient:
            patient = Patient(
                patient_id=vitals.patient_id,
                mrn=vitals.patient_id,
                name=vitals.patient_name or "Unknown",
                gender=vitals.patient_gender,
                dob=vitals.patient_dob,
                bed_id=vitals.bed_id,
            )
            db.add(patient)
        else:
            if vitals.patient_name:
                patient.name = vitals.patient_name
            if vitals.patient_gender:
                patient.gender = vitals.patient_gender
            if vitals.patient_dob:
                patient.dob = vitals.patient_dob
            if vitals.bed_id:
                patient.bed_id = vitals.bed_id
        
        # 3. Create vital reading
        from models import VitalReading as VR
        reading = VR(
            device_id=vitals.device_id,
            patient_id=vitals.patient_id,
            timestamp=vitals.timestamp,
            heart_rate=vitals.heart_rate,
            spo2=vitals.spo2,
            systolic_bp=vitals.systolic_bp,
            diastolic_bp=vitals.diastolic_bp,
            map_bp=vitals.map_bp,
            respiratory_rate=vitals.respiratory_rate,
            temperature=vitals.temperature,
            transmitted=True  # Already received = transmitted
        )
        db.add(reading)
        db.commit()
        db.refresh(reading)
        
        # 4. Broadcast to WebSocket clients
        await ws_manager.broadcast_vitals(vitals.model_dump(mode="json"))
        
        logger.info(f"Push-vitals received for device {vitals.device_id}")
        
        return {
            "status": "ok",
            "reading_id": reading.id,
            "device_id": vitals.device_id,
            "patient_id": vitals.patient_id
        }
    
    except HTTPException:
        raise
    except Exception as e:
        logger.error(f"Push-vitals error: {e}")
        db.rollback()
        raise HTTPException(status_code=500, detail=f"Failed to store vitals: {str(e)}")


# === Patient-to-Monitor Matching Endpoint ===
def _normalize_name(s: str) -> str:
    """Lowercase, strip punctuation and extra spaces for fuzzy name comparison."""
    import re
    if not s:
        return ""
    return re.sub(r"[^a-z0-9\s]", "", s.lower()).split()

def _normalize_dob(dob: str) -> str:
    """Normalize DOB to YYYYMMDD regardless of input format (YYYY-MM-DD / YYYYMMDD / DD-MM-YYYY)."""
    if not dob:
        return ""
    dob = dob.strip().replace("/", "-")
    if len(dob) == 8 and dob.isdigit():
        return dob  # already YYYYMMDD
    parts = dob.split("-")
    if len(parts) == 3:
        if len(parts[0]) == 4:              # YYYY-MM-DD
            return "".join(parts)
        elif len(parts[2]) == 4:            # DD-MM-YYYY
            return parts[2] + parts[1] + parts[0]
    return dob.replace("-", "")

def _gender_code(g: str) -> str:
    """Return single-letter gender code: M / F / U."""
    if not g:
        return ""
    g = g.strip().upper()
    if g in ("M", "MALE"):
        return "M"
    if g in ("F", "FEMALE"):
        return "F"
    return "U"

def _calculate_age(dob_str: str) -> Optional[int]:
    """Calculate age from YYYYMMDD string."""
    if not dob_str:
        return None
    normalized = _normalize_dob(dob_str)
    if len(normalized) != 8 or not normalized.isdigit():
        return None
    try:
        birth_year = int(normalized[:4])
        birth_month = int(normalized[4:6])
        birth_day = int(normalized[6:])
        today = datetime.now()
        return today.year - birth_year - ((today.month, today.day) < (birth_month, birth_day))
    except Exception:
        return None

@router.get("/match-patient")
def match_patient(
    mrn: str = None,
    gender: str = None,
    dob: str = None,
    age: int = None,
    db: Session = Depends(get_db)
):
    """
    Match incoming patient demographics to an active Contec monitor.
    Uses 4-point verification: MRN, Gender, DOB, Age.

    Call this from the dashboard iframe URL:
      /api/dashboard?minimal=true&mrn=MRN001&gender=M&dob=19900115&age=36

    Returns:
      { matched: true/false, device_id, patient_id, bed_id, device_status, ... }
    """
    if not mrn:
        return {"matched": False, "reason": "No MRN supplied"}

    # Normalize incoming params
    in_mrn    = (mrn or "").strip().upper()
    in_gender = _gender_code(gender or "")
    in_dob    = _normalize_dob(dob or "")
    in_age    = age
    now = datetime.now(timezone.utc)

    # Fetch all patients from monitor database (populated ONLY by monitor HL7/push-vitals)
    # Do NOT auto-register — patients must exist from actual monitor data
    all_patients = db.query(Patient).all()
    best_match = None

    for p in all_patients:
        # --- MRN check (must match exactly) ---
        p_mrn = (p.mrn or p.patient_id or "").strip().upper()
        if p_mrn != in_mrn:
            continue

        # --- Gender check (must match exactly) ---
        p_gender = _gender_code(p.gender or "")
        if p_gender != in_gender:
            continue

        # --- DOB check (must match exactly) ---
        p_dob = _normalize_dob(p.dob or "")
        if p_dob != in_dob:
            continue

        # --- Age check (must match exactly) ---
        if in_age is not None:
            p_age = _calculate_age(p.dob or "")
            if p_age is None or p_age != in_age:
                continue

        # If MRN, gender, DOB, and Age all match, we have our matched patient
        best_match = p
        break

    if not best_match:
        return {
            "matched": False,
            "reason": "Patient verification failed. MRN, Gender, DOB, and Age must match exactly."
        }

    matched_patient = best_match

    # Find the most recent vital reading for this patient
    latest = (
        db.query(VitalReading)
        .filter(VitalReading.patient_id == matched_patient.patient_id)
        .order_by(VitalReading.timestamp.desc())
        .first()
    )

    # Fallback: If this patient has no readings yet, check if there is an active device
    # transmitting data under 'UNKNOWN' in the last 15 seconds. This links binary monitors to the verified patient.
    if not latest:
        active_unknown_reading = (
            db.query(VitalReading)
            .filter(VitalReading.patient_id == "UNKNOWN")
            .order_by(VitalReading.timestamp.desc())
            .first()
        )
        if active_unknown_reading:
            reading_time = active_unknown_reading.timestamp
            if reading_time.tzinfo is None:
                reading_time = reading_time.replace(tzinfo=timezone.utc)
            if (now - reading_time).total_seconds() < 15.0:
                latest = active_unknown_reading

    if not latest:
        return {
            "matched": True,
            "patient_id": matched_patient.patient_id,
            "device_id": None,
            "bed_id": matched_patient.bed_id,
            "reason": "Patient found/created, but no active monitor data received yet"
        }

    # Get device status
    device = db.query(Device).filter(Device.device_id == latest.device_id).first()
    device_status = "unknown"
    if device:
        last_seen = device.last_seen
        if last_seen.tzinfo is None:
            last_seen = last_seen.replace(tzinfo=timezone.utc)
        device_status = "active" if (now - last_seen).total_seconds() < 15 else "offline"

    return {
        "matched": True,
        "patient_id": matched_patient.patient_id,
        "patient_name": matched_patient.name,
        "patient_gender": matched_patient.gender,
        "patient_dob": matched_patient.dob,
        "device_id": latest.device_id,
        "bed_id": matched_patient.bed_id,
        "device_status": device_status,
        "last_reading_at": latest.timestamp.isoformat() if latest.timestamp else None,
        "match_score": 100,
    }