from fastapi import APIRouter, Depends, HTTPException, Query
from sqlalchemy.orm import Session
from datetime import datetime
from typing import Dict, Any, Optional

from backend.database import get_db
from backend.services.snapshot import emit_status_snapshot
from backend.models import RosterUnit

router = APIRouter(prefix="/api", tags=["units"])


@router.get("/unit/{unit_id}")
def get_unit_detail(unit_id: str, db: Session = Depends(get_db)):
    """
    Returns detailed data for a single unit.
    """
    snapshot = emit_status_snapshot()

    if unit_id not in snapshot["units"]:
        raise HTTPException(status_code=404, detail=f"Unit {unit_id} not found")

    unit_data = snapshot["units"][unit_id]

    # Mock coordinates for now (will be replaced with real data)
    mock_coords = {
        "BE1234": {"lat": 37.7749, "lon": -122.4194, "location": "San Francisco, CA"},
        "BE5678": {"lat": 34.0522, "lon": -118.2437, "location": "Los Angeles, CA"},
        "BE9012": {"lat": 40.7128, "lon": -74.0060, "location": "New York, NY"},
        "BE3456": {"lat": 41.8781, "lon": -87.6298, "location": "Chicago, IL"},
        "BE7890": {"lat": 29.7604, "lon": -95.3698, "location": "Houston, TX"},
    }

    coords = mock_coords.get(unit_id, {"lat": 39.8283, "lon": -98.5795, "location": "Unknown"})

    return {
        "id": unit_id,
        "status": unit_data["status"],
        "age": unit_data["age"],
        "last_seen": unit_data["last"],
        "last_file": unit_data.get("fname", ""),
        "deployed": unit_data["deployed"],
        "note": unit_data.get("note", ""),
        "coordinates": coords
    }


@router.get("/units/{unit_id}")
def get_unit_by_id(unit_id: str, db: Session = Depends(get_db)):
    """
    Get unit data directly from the roster (for settings/configuration).
    """
    unit = db.query(RosterUnit).filter_by(id=unit_id).first()

    if not unit:
        raise HTTPException(status_code=404, detail=f"Unit {unit_id} not found")

    return {
        "id": unit.id,
        "unit_type": unit.unit_type,
        "device_type": unit.device_type,
        "deployed": unit.deployed,
        "retired": unit.retired,
        "note": unit.note,
        "location": unit.location,
        "address": unit.address,
        "coordinates": unit.coordinates,
        "slm_host": unit.slm_host,
        "slm_tcp_port": unit.slm_tcp_port,
        "slm_ftp_port": unit.slm_ftp_port,
        "slm_model": unit.slm_model,
        "slm_serial_number": unit.slm_serial_number,
        "deployed_with_modem_id": unit.deployed_with_modem_id
    }


@router.get("/units/{unit_id}/events")
async def get_unit_events(
    unit_id: str,
    bucket: str = Query("all", regex="^(all|attributed|unattributed)$"),
    from_dt: Optional[datetime] = Query(None),
    to_dt: Optional[datetime] = Query(None),
    false_trigger: Optional[bool] = Query(None),
    limit: int = Query(500, ge=1, le=5000),
    db: Session = Depends(get_db),
):
    """
    Return SFM events for a single unit, annotated with assignment attribution.

    Each event includes an `attribution` object pointing at the project/location
    it falls into (or null if outside every assignment window).  Unattributed
    events also carry a `nearest_assignment` field with `delta_days` so the
    operator can see how far off the nearest assignment is — useful for
    deciding whether to backdate the assignment to absorb the event.

    Bucket filter:
      - all (default): every event
      - attributed:    only events inside an assignment window
      - unattributed:  only orphan events (the diagnostic bucket)

    Non-seismograph units return an empty events list.  The route does not
    404 for SLMs/modems so the unit detail page can render the section
    conditionally without depending on the response shape.
    """
    unit = db.query(RosterUnit).filter_by(id=unit_id).first()
    if not unit:
        raise HTTPException(status_code=404, detail=f"Unit {unit_id} not found")

    if unit.device_type != "seismograph":
        return {
            "events":            [],
            "count":              0,
            "stats": {
                "event_count":         0,
                "unattributed_count":  0,
                "peak_pvs":            None,
                "peak_pvs_at":         None,
                "peak_pvs_serial":     None,
                "last_event":          None,
                "false_trigger_count": 0,
            },
            "assignments_total":  0,
            "device_type":        unit.device_type,
        }

    from backend.services.sfm_events import events_for_unit

    result = await events_for_unit(
        db,
        unit_id,
        bucket=bucket,
        from_dt=from_dt,
        to_dt=to_dt,
        false_trigger=false_trigger,
        limit=limit,
    )
    result["device_type"] = unit.device_type
    return result