from fastapi import APIRouter, Depends, HTTPException
from sqlalchemy.orm import Session
from pydantic import BaseModel
from datetime import datetime
from typing import Optional, List

from backend.database import get_db
from backend.models import Emitter, WatcherAgent

router = APIRouter()


# Helper function to detect unit type from unit ID
def detect_unit_type(unit_id: str) -> str:
    """
    Automatically detect if a unit is Series 3 or Series 4 based on ID pattern.

    Series 4 (Micromate) units have IDs starting with "UM" followed by digits (e.g., UM11719)
    Series 3 units typically have other patterns

    Returns:
        "series4" if the unit ID matches Micromate pattern (UM#####)
        "series3" otherwise
    """
    if not unit_id:
        return "unknown"

    # Series 4 (Micromate) pattern: UM followed by digits
    if unit_id.upper().startswith("UM") and len(unit_id) > 2:
        # Check if remaining characters after "UM" are digits
        rest = unit_id[2:]
        if rest.isdigit():
            return "series4"

    # Default to series3 for other patterns
    return "series3"


# Pydantic schemas for request/response validation
class EmitterReport(BaseModel):
    unit: str
    unit_type: str
    timestamp: str
    file: str
    status: str


class EmitterResponse(BaseModel):
    id: str
    unit_type: str
    last_seen: datetime
    last_file: str
    status: str
    notes: Optional[str] = None

    class Config:
        from_attributes = True


@router.post("/emitters/report", status_code=200)
def report_emitter(report: EmitterReport, db: Session = Depends(get_db)):
    """
    Endpoint for emitters to report their status.
    Creates a new emitter if it doesn't exist, or updates an existing one.
    """
    try:
        # Parse the timestamp
        timestamp = datetime.fromisoformat(report.timestamp.replace('Z', '+00:00'))
    except ValueError:
        raise HTTPException(status_code=400, detail="Invalid timestamp format")

    # Check if emitter already exists
    emitter = db.query(Emitter).filter(Emitter.id == report.unit).first()

    if emitter:
        # Update existing emitter
        emitter.unit_type = report.unit_type
        emitter.last_seen = timestamp
        emitter.last_file = report.file
        emitter.status = report.status
    else:
        # Create new emitter
        emitter = Emitter(
            id=report.unit,
            unit_type=report.unit_type,
            last_seen=timestamp,
            last_file=report.file,
            status=report.status
        )
        db.add(emitter)

    db.commit()
    db.refresh(emitter)

    return {
        "message": "Emitter report received",
        "unit": emitter.id,
        "status": emitter.status
    }


@router.get("/fleet/status", response_model=List[EmitterResponse])
def get_fleet_status(db: Session = Depends(get_db)):
    """
    Returns a list of all emitters and their current status.
    """
    emitters = db.query(Emitter).all()
    return emitters

# ── Watcher agent upsert helper ───────────────────────────────────────────────

def _upsert_watcher_agent(db: Session, source_id: str, source_type: str,
                           version: str, ip_address: str, log_tail: str,
                           status: str) -> None:
    """Create or update the WatcherAgent row for a given source_id."""
    agent = db.query(WatcherAgent).filter(WatcherAgent.id == source_id).first()
    if agent:
        agent.source_type = source_type
        agent.version = version
        agent.last_seen = datetime.utcnow()
        agent.status = status
        if ip_address:
            agent.ip_address = ip_address
        if log_tail is not None:
            agent.log_tail = log_tail
    else:
        agent = WatcherAgent(
            id=source_id,
            source_type=source_type,
            version=version,
            last_seen=datetime.utcnow(),
            status=status,
            ip_address=ip_address,
            log_tail=log_tail,
        )
        db.add(agent)


# series3v1.1 Standardized Heartbeat Schema (multi-unit)
from fastapi import Request

@router.post("/api/series3/heartbeat", status_code=200)
async def series3_heartbeat(request: Request, db: Session = Depends(get_db)):
    """
    Accepts a full telemetry payload from the Series3 emitter.
    Updates or inserts each unit into the database.
    """
    payload = await request.json()

    source = payload.get("source_id")
    units = payload.get("units", [])
    version = payload.get("version")
    log_tail = payload.get("log_tail")  # list of strings or None
    import json as _json
    log_tail_str = _json.dumps(log_tail) if log_tail is not None else None
    client_ip = request.client.host if request.client else None

    print("\n=== Series 3 Heartbeat ===")
    print("Source:", source)
    print("Units received:", len(units))
    print("==========================\n")

    results = []

    for u in units:
        uid = u.get("unit_id")
        last_event_time = u.get("last_event_time")
        event_meta = u.get("event_metadata", {})
        age_minutes = u.get("age_minutes")

        try:
            if last_event_time:
                ts = datetime.fromisoformat(last_event_time.replace("Z", "+00:00"))
            else:
                ts = None
        except:
            ts = None

        # Pull from DB
        emitter = db.query(Emitter).filter(Emitter.id == uid).first()

        # File name (from event_metadata)
        last_file = event_meta.get("file_name")
        status = "Unknown"

        # Determine status based on age
        if age_minutes is None:
            status = "Missing"
        elif age_minutes > 24 * 60:
            status = "Missing"
        elif age_minutes > 12 * 60:
            status = "Pending"
        else:
            status = "OK"

        if emitter:
            # Update existing
            emitter.last_seen = ts
            emitter.last_file = last_file
            emitter.status = status
            # Update unit_type if it was incorrectly classified
            detected_type = detect_unit_type(uid)
            if emitter.unit_type != detected_type:
                emitter.unit_type = detected_type
        else:
            # Insert new - auto-detect unit type from ID
            detected_type = detect_unit_type(uid)
            emitter = Emitter(
                id=uid,
                unit_type=detected_type,
                last_seen=ts,
                last_file=last_file,
                status=status
            )
            db.add(emitter)

        results.append({"unit": uid, "status": status})

    if source:
        _upsert_watcher_agent(db, source, "series3_watcher", version,
                               client_ip, log_tail_str, "ok")

    db.commit()

    # Check if an update has been triggered for this agent
    update_available = False
    if source:
        agent = db.query(WatcherAgent).filter(WatcherAgent.id == source).first()
        if agent and agent.update_pending:
            update_available = True
            agent.update_pending = False
            db.commit()

    return {
        "message": "Heartbeat processed",
        "source": source,
        "units_processed": len(results),
        "results": results,
        "update_available": update_available,
    }


# series4 (Micromate) Standardized Heartbeat Schema
@router.post("/api/series4/heartbeat", status_code=200)
async def series4_heartbeat(request: Request, db: Session = Depends(get_db)):
    """
    Accepts a full telemetry payload from the Series4 (Micromate) emitter.
    Updates or inserts each unit into the database.

    Expected payload:
    {
      "source": "series4_emitter",
      "generated_at": "2025-12-04T20:01:00",
      "units": [
        {
          "unit_id": "UM11719",
          "type": "micromate",
          "project_hint": "Clearwater - ECMS 57940",
          "last_call": "2025-12-04T19:30:42",
          "status": "OK",
          "age_days": 0.04,
          "age_hours": 0.9,
          "mlg_path": "C:\\THORDATA\\..."
        }
      ]
    }
    """
    payload = await request.json()

    # Accept source_id (new standard field) with fallback to legacy "source" key
    source = payload.get("source_id") or payload.get("source", "series4_emitter")
    units = payload.get("units", [])
    version = payload.get("version")
    log_tail = payload.get("log_tail")
    import json as _json
    log_tail_str = _json.dumps(log_tail) if log_tail is not None else None
    client_ip = request.client.host if request.client else None

    print("\n=== Series 4 Heartbeat ===")
    print("Source:", source)
    print("Units received:", len(units))
    print("==========================\n")

    results = []

    for u in units:
        uid = u.get("unit_id")
        last_call_str = u.get("last_call")
        status = u.get("status", "Unknown")
        mlg_path = u.get("mlg_path")
        project_hint = u.get("project_hint")

        # Parse last_call timestamp
        try:
            if last_call_str:
                ts = datetime.fromisoformat(last_call_str.replace("Z", "+00:00"))
            else:
                ts = None
        except:
            ts = None

        # Pull from DB
        emitter = db.query(Emitter).filter(Emitter.id == uid).first()

        if emitter:
            # Update existing
            emitter.last_seen = ts
            emitter.last_file = mlg_path
            emitter.status = status
            # Update unit_type if it was incorrectly classified
            detected_type = detect_unit_type(uid)
            if emitter.unit_type != detected_type:
                emitter.unit_type = detected_type
            # Optionally update notes with project hint if it exists
            if project_hint and not emitter.notes:
                emitter.notes = f"Project: {project_hint}"
        else:
            # Insert new - auto-detect unit type from ID
            detected_type = detect_unit_type(uid)
            notes = f"Project: {project_hint}" if project_hint else None
            emitter = Emitter(
                id=uid,
                unit_type=detected_type,
                last_seen=ts,
                last_file=mlg_path,
                status=status,
                notes=notes
            )
            db.add(emitter)

        results.append({"unit": uid, "status": status})

    if source:
        _upsert_watcher_agent(db, source, "series4_watcher", version,
                               client_ip, log_tail_str, "ok")

    db.commit()

    # Check if an update has been triggered for this agent
    update_available = False
    if source:
        agent = db.query(WatcherAgent).filter(WatcherAgent.id == source).first()
        if agent and agent.update_pending:
            update_available = True
            agent.update_pending = False
            db.commit()

    return {
        "message": "Heartbeat processed",
        "source": source,
        "units_processed": len(results),
        "results": results,
        "update_available": update_available,
    }