terra-view/backend/routers/project_locations.py

"""
Project Locations Router

Handles monitoring locations (NRLs for sound, monitoring points for vibration)
and unit assignments within projects.
"""

from fastapi import APIRouter, Request, Depends, HTTPException, Query
from fastapi.responses import HTMLResponse, JSONResponse
from sqlalchemy.orm import Session
from sqlalchemy import and_, or_
from datetime import datetime
from typing import Optional
import uuid
import json

from fastapi import UploadFile, File
import zipfile
import hashlib
import io
from pathlib import Path

from backend.database import get_db
from backend.models import (
    Project,
    ProjectType,
    ProjectModule,
    MonitoringLocation,
    UnitAssignment,
    RosterUnit,
    MonitoringSession,
    DataFile,
    UnitHistory,
    ScheduledAction,
)
from backend.templates_config import templates
from backend.utils.timezone import local_to_utc

router = APIRouter(prefix="/api/projects/{project_id}", tags=["project-locations"])


# ── Audit log helper ──────────────────────────────────────────────────────────
# Mirrors record_history() in roster_edit.py.  Kept local to avoid cross-router
# imports.  The four assignment endpoints below use this to write UnitHistory
# rows that the unit-detail deployment timeline (Phase 4) renders.

def _record_assignment_history(
    db: Session,
    unit_id: str,
    change_type: str,
    *,
    old_value: Optional[str] = None,
    new_value: Optional[str] = None,
    notes: Optional[str] = None,
) -> None:
    """Append a UnitHistory row for an assignment-lifecycle event.

    change_type values used:
      - assignment_created   — unit assigned to a location (new assignment)
      - assignment_ended     — unit unassigned / removed (assigned_until set)
      - assignment_swapped   — unit replaced by another at the same location
      - assignment_updated   — assignment dates / notes edited via PATCH

    Caller is responsible for db.commit().
    """
    db.add(UnitHistory(
        unit_id=unit_id,
        change_type=change_type,
        field_name="unit_assignment",
        old_value=old_value,
        new_value=new_value,
        changed_at=datetime.utcnow(),
        source="manual",
        notes=notes,
    ))


# ============================================================================
# Shared helpers
# ============================================================================

def _require_module(project, module_type: str, db: Session) -> None:
    """Raise 400 if the project does not have the given module enabled."""
    if not project:
        raise HTTPException(status_code=404, detail="Project not found.")
    exists = db.query(ProjectModule).filter_by(
        project_id=project.id, module_type=module_type, enabled=True
    ).first()
    if not exists:
        raise HTTPException(
            status_code=400,
            detail=f"This project does not have the {module_type.replace('_', ' ').title()} module enabled.",
        )


# ============================================================================
# Session period helpers
# ============================================================================

def _derive_period_type(dt: datetime) -> str:
    """
    Classify a session start time into one of four period types.
    Night = 22:00–07:00, Day = 07:00–22:00.
    Weekend = Saturday (5) or Sunday (6).
    """
    is_weekend = dt.weekday() >= 5
    is_night = dt.hour >= 22 or dt.hour < 7
    if is_weekend:
        return "weekend_night" if is_night else "weekend_day"
    return "weekday_night" if is_night else "weekday_day"


def _build_session_label(dt: datetime, location_name: str, period_type: str) -> str:
    """Build a human-readable session label, e.g. 'NRL-1 — Sun 2/23 — Night'.
    Uses started_at date as-is; user can correct period_type in the wizard.
    """
    day_abbr = dt.strftime("%a")
    date_str = f"{dt.month}/{dt.day}"
    period_str = {
        "weekday_day":   "Day",
        "weekday_night": "Night",
        "weekend_day":   "Day",
        "weekend_night": "Night",
    }.get(period_type, "")
    parts = [p for p in [location_name, f"{day_abbr} {date_str}", period_str] if p]
    return " — ".join(parts)


# ============================================================================
# Monitoring Locations CRUD
# ============================================================================

@router.get("/locations", response_class=HTMLResponse)
async def get_project_locations(
    project_id: str,
    request: Request,
    db: Session = Depends(get_db),
    location_type: Optional[str] = Query(None),
):
    """
    Get all monitoring locations for a project.
    Returns HTML partial with location list, split into active + removed.
    """
    project = db.query(Project).filter_by(id=project_id).first()
    if not project:
        raise HTTPException(status_code=404, detail="Project not found")

    query = db.query(MonitoringLocation).filter_by(project_id=project_id)

    # Filter by type if provided
    if location_type:
        query = query.filter_by(location_type=location_type)

    locations = query.order_by(MonitoringLocation.name).all()

    # Enrich with assignment info, splitting active vs removed.
    active_data:  list = []
    removed_data: list = []
    for location in locations:
        # Get active assignment (active = assigned_until IS NULL).  For
        # removed locations this will normally be None because the
        # /remove cascade closes them, but check anyway for resilience
        # against legacy data.
        assignment = db.query(UnitAssignment).filter(
            and_(
                UnitAssignment.location_id == location.id,
                UnitAssignment.assigned_until == None,
            )
        ).first()

        assigned_unit = None
        if assignment:
            assigned_unit = db.query(RosterUnit).filter_by(id=assignment.unit_id).first()

        # Count monitoring sessions
        session_count = db.query(MonitoringSession).filter_by(
            location_id=location.id
        ).count()

        item = {
            "location":      location,
            "assignment":    assignment,
            "assigned_unit": assigned_unit,
            "session_count": session_count,
        }
        if location.removed_at is None:
            active_data.append(item)
        else:
            removed_data.append(item)

    return templates.TemplateResponse("partials/projects/location_list.html", {
        "request":            request,
        "project":            project,
        "locations":          active_data,           # back-compat alias
        "active_locations":   active_data,
        "removed_locations":  removed_data,
    })


@router.get("/locations-json")
async def get_project_locations_json(
    project_id: str,
    db: Session = Depends(get_db),
    location_type: Optional[str] = Query(None),
    include_removed: bool = Query(False),
):
    """
    Get all monitoring locations for a project as JSON.
    Used by the schedule modal to populate location dropdown.

    Removed locations are filtered out by default (you can't schedule
    a new action at a removed location).  Pass `include_removed=true`
    to get them too — useful for historical / reporting views.
    """
    project = db.query(Project).filter_by(id=project_id).first()
    if not project:
        raise HTTPException(status_code=404, detail="Project not found")

    query = db.query(MonitoringLocation).filter_by(project_id=project_id)

    if location_type:
        query = query.filter_by(location_type=location_type)

    if not include_removed:
        query = query.filter(MonitoringLocation.removed_at == None)   # noqa: E711

    locations = query.order_by(MonitoringLocation.name).all()

    return [
        {
            "id":             loc.id,
            "name":           loc.name,
            "location_type":  loc.location_type,
            "description":    loc.description,
            "address":        loc.address,
            "coordinates":    loc.coordinates,
            "removed_at":     loc.removed_at.isoformat() if loc.removed_at else None,
            "removal_reason": loc.removal_reason,
        }
        for loc in locations
    ]


@router.post("/locations/create")
async def create_location(
    project_id: str,
    request: Request,
    db: Session = Depends(get_db),
):
    """
    Create a new monitoring location within a project.
    """
    project = db.query(Project).filter_by(id=project_id).first()
    if not project:
        raise HTTPException(status_code=404, detail="Project not found")

    form_data = await request.form()

    location = MonitoringLocation(
        id=str(uuid.uuid4()),
        project_id=project_id,
        location_type=form_data.get("location_type"),
        name=form_data.get("name"),
        description=form_data.get("description"),
        coordinates=form_data.get("coordinates"),
        address=form_data.get("address"),
        location_metadata=form_data.get("location_metadata"),  # JSON string
    )

    db.add(location)
    db.commit()
    db.refresh(location)

    return JSONResponse({
        "success": True,
        "location_id": location.id,
        "message": f"Location '{location.name}' created successfully",
    })


@router.put("/locations/{location_id}")
async def update_location(
    project_id: str,
    location_id: str,
    request: Request,
    db: Session = Depends(get_db),
):
    """
    Update a monitoring location.
    """
    location = db.query(MonitoringLocation).filter_by(
        id=location_id,
        project_id=project_id,
    ).first()

    if not location:
        raise HTTPException(status_code=404, detail="Location not found")

    data = await request.json()

    # Update fields if provided
    if "name" in data:
        location.name = data["name"]
    if "description" in data:
        location.description = data["description"]
    if "location_type" in data:
        location.location_type = data["location_type"]
    if "coordinates" in data:
        location.coordinates = data["coordinates"]
    if "address" in data:
        location.address = data["address"]
    if "location_metadata" in data:
        location.location_metadata = data["location_metadata"]

    location.updated_at = datetime.utcnow()

    db.commit()

    return {"success": True, "message": "Location updated successfully"}


@router.delete("/locations/{location_id}")
async def delete_location(
    project_id: str,
    location_id: str,
    db: Session = Depends(get_db),
):
    """
    Delete a monitoring location.
    """
    location = db.query(MonitoringLocation).filter_by(
        id=location_id,
        project_id=project_id,
    ).first()

    if not location:
        raise HTTPException(status_code=404, detail="Location not found")

    # Check if location has active assignments (active = assigned_until IS NULL)
    active_assignments = db.query(UnitAssignment).filter(
        and_(
            UnitAssignment.location_id == location_id,
            UnitAssignment.assigned_until == None,
        )
    ).count()

    if active_assignments > 0:
        raise HTTPException(
            status_code=400,
            detail="Cannot delete location with active unit assignments. Unassign units first.",
        )

    db.delete(location)
    db.commit()

    return {"success": True, "message": "Location deleted successfully"}


@router.post("/locations/{location_id}/remove")
async def remove_location(
    project_id: str,
    location_id: str,
    request: Request,
    db: Session = Depends(get_db),
):
    """
    Soft-remove a monitoring location — mark it as no longer actively
    monitored without destroying it.

    Use case: a client drops a location from scope mid-project, but the
    historical events recorded there should remain attributed.  Deleting
    would orphan those events; this preserves them.

    Cascading side-effects:
      1. All active UnitAssignment rows at this location are closed
         (assigned_until = effective_date, status = "completed").
         Units become available for other deployments.
      2. All pending ScheduledAction rows at this location are cancelled
         (execution_status = "cancelled").
      3. Historical events stay attributed (attribution is window-based;
         events with timestamp < effective_date still match the
         now-closed assignment windows).

    Accepts JSON body:
      - effective_date: ISO datetime (optional, defaults to now)
      - reason:         operator note (optional)
    """
    location = db.query(MonitoringLocation).filter_by(
        id=location_id,
        project_id=project_id,
    ).first()

    if not location:
        raise HTTPException(status_code=404, detail="Location not found")

    if location.removed_at is not None:
        raise HTTPException(
            status_code=400,
            detail=f"Location is already removed (as of {location.removed_at.isoformat()}).",
        )

    # Body is optional — POST with no body is fine and means "remove now,
    # no reason given."
    try:
        payload = await request.json()
    except Exception:
        payload = {}

    # Effective date: accept "YYYY-MM-DDTHH:MM" from datetime-local inputs or
    # full ISO.  Defaults to now if absent/empty.
    raw_eff = payload.get("effective_date")
    if raw_eff:
        try:
            effective_date = datetime.fromisoformat(raw_eff)
        except (TypeError, ValueError):
            raise HTTPException(
                status_code=400,
                detail=f"Invalid effective_date: {raw_eff!r}",
            )
    else:
        effective_date = datetime.utcnow()

    reason = (payload.get("reason") or "").strip() or None

    # 1. Close active assignments at this location.
    active_assignments = db.query(UnitAssignment).filter(
        and_(
            UnitAssignment.location_id == location_id,
            UnitAssignment.assigned_until == None,    # noqa: E711 — SQL NULL
        )
    ).all()

    for a in active_assignments:
        a.status         = "completed"
        a.assigned_until = effective_date
        _record_assignment_history(
            db,
            unit_id=a.unit_id,
            change_type="assignment_ended",
            old_value=location.name,
            new_value="location removed",
            notes=f"Location '{location.name}' marked as removed"
                  + (f" — {reason}" if reason else ""),
        )

    # 2. Cancel pending scheduled actions at this location.
    pending_actions = db.query(ScheduledAction).filter(
        and_(
            ScheduledAction.location_id == location_id,
            ScheduledAction.execution_status == "pending",
            ScheduledAction.scheduled_time >= effective_date,
        )
    ).all()

    for sa in pending_actions:
        sa.execution_status = "cancelled"
        sa.error_message = (
            f"Cancelled: location '{location.name}' marked as removed"
            + (f" — {reason}" if reason else "")
        )

    # 3. Mark the location itself as removed.
    location.removed_at     = effective_date
    location.removal_reason = reason
    location.updated_at     = datetime.utcnow()

    db.commit()

    return {
        "success":               True,
        "message":               f"Location '{location.name}' marked as removed",
        "effective_date":        effective_date.isoformat(),
        "assignments_closed":    len(active_assignments),
        "actions_cancelled":     len(pending_actions),
    }


@router.post("/locations/{location_id}/restore")
async def restore_location(
    project_id: str,
    location_id: str,
    db: Session = Depends(get_db),
):
    """
    Restore a previously-removed monitoring location to active.

    Clears `removed_at` and `removal_reason`.  Does NOT automatically
    re-open the assignments or scheduled actions that were closed when
    the location was removed — those stay closed and the operator can
    create new ones if they want to resume monitoring.
    """
    location = db.query(MonitoringLocation).filter_by(
        id=location_id,
        project_id=project_id,
    ).first()

    if not location:
        raise HTTPException(status_code=404, detail="Location not found")

    if location.removed_at is None:
        raise HTTPException(
            status_code=400,
            detail="Location is already active.",
        )

    location.removed_at     = None
    location.removal_reason = None
    location.updated_at     = datetime.utcnow()

    db.commit()

    return {
        "success": True,
        "message": f"Location '{location.name}' restored to active",
    }


# ============================================================================
# Unit Assignments
# ============================================================================

@router.get("/assignments", response_class=HTMLResponse)
async def get_project_assignments(
    project_id: str,
    request: Request,
    db: Session = Depends(get_db),
    status: Optional[str] = Query("active"),
):
    """
    Get all unit assignments for a project.
    Returns HTML partial with assignment list.
    """
    query = db.query(UnitAssignment).filter_by(project_id=project_id)

    if status:
        query = query.filter_by(status=status)

    assignments = query.order_by(UnitAssignment.assigned_at.desc()).all()

    # Enrich with unit and location details
    assignments_data = []
    for assignment in assignments:
        unit = db.query(RosterUnit).filter_by(id=assignment.unit_id).first()
        location = db.query(MonitoringLocation).filter_by(id=assignment.location_id).first()

        assignments_data.append({
            "assignment": assignment,
            "unit": unit,
            "location": location,
        })

    return templates.TemplateResponse("partials/projects/assignment_list.html", {
        "request": request,
        "project_id": project_id,
        "assignments": assignments_data,
    })


@router.post("/locations/{location_id}/assign")
async def assign_unit_to_location(
    project_id: str,
    location_id: str,
    request: Request,
    db: Session = Depends(get_db),
):
    """
    Assign a unit to a monitoring location.
    """
    location = db.query(MonitoringLocation).filter_by(
        id=location_id,
        project_id=project_id,
    ).first()

    if not location:
        raise HTTPException(status_code=404, detail="Location not found")

    form_data = await request.form()
    unit_id = form_data.get("unit_id")

    # Verify unit exists and matches location type
    unit = db.query(RosterUnit).filter_by(id=unit_id).first()
    if not unit:
        raise HTTPException(status_code=404, detail="Unit not found")

    # Check device type matches location type
    expected_device_type = "slm" if location.location_type == "sound" else "seismograph"
    if unit.device_type != expected_device_type:
        raise HTTPException(
            status_code=400,
            detail=f"Unit type '{unit.device_type}' does not match location type '{location.location_type}'",
        )

    # Check if location already has an active assignment (active = assigned_until IS NULL)
    existing_assignment = db.query(UnitAssignment).filter(
        and_(
            UnitAssignment.location_id == location_id,
            UnitAssignment.assigned_until == None,
        )
    ).first()

    if existing_assignment:
        raise HTTPException(
            status_code=400,
            detail=f"Location already has an active unit assignment ({existing_assignment.unit_id}). Use swap to replace it.",
        )

    # Create new assignment
    assigned_until_str = form_data.get("assigned_until")
    assigned_until = datetime.fromisoformat(assigned_until_str) if assigned_until_str else None

    assignment = UnitAssignment(
        id=str(uuid.uuid4()),
        unit_id=unit_id,
        location_id=location_id,
        project_id=project_id,
        device_type=unit.device_type,
        assigned_until=assigned_until,
        status="active",
        notes=form_data.get("notes"),
    )

    db.add(assignment)
    _record_assignment_history(
        db,
        unit_id=unit_id,
        change_type="assignment_created",
        new_value=f"{location.name} (project: {location.project_id})",
        notes=form_data.get("notes"),
    )
    db.commit()
    db.refresh(assignment)

    return JSONResponse({
        "success": True,
        "assignment_id": assignment.id,
        "message": f"Unit '{unit_id}' assigned to '{location.name}'",
    })


@router.post("/assignments/{assignment_id}/unassign")
async def unassign_unit(
    project_id: str,
    assignment_id: str,
    db: Session = Depends(get_db),
):
    """
    Unassign a unit from a location.
    """
    assignment = db.query(UnitAssignment).filter_by(
        id=assignment_id,
        project_id=project_id,
    ).first()

    if not assignment:
        raise HTTPException(status_code=404, detail="Assignment not found")

    # Check if there are active monitoring sessions
    active_sessions = db.query(MonitoringSession).filter(
        and_(
            MonitoringSession.location_id == assignment.location_id,
            MonitoringSession.unit_id == assignment.unit_id,
            MonitoringSession.status == "recording",
        )
    ).count()

    if active_sessions > 0:
        raise HTTPException(
            status_code=400,
            detail="Cannot unassign unit with active monitoring sessions. Stop monitoring first.",
        )

    assignment.status = "completed"
    assignment.assigned_until = datetime.utcnow()

    location = db.query(MonitoringLocation).filter_by(id=assignment.location_id).first()
    _record_assignment_history(
        db,
        unit_id=assignment.unit_id,
        change_type="assignment_ended",
        old_value=location.name if location else assignment.location_id,
        new_value="unassigned",
    )

    db.commit()

    return {"success": True, "message": "Unit unassigned successfully"}


@router.patch("/assignments/{assignment_id}")
async def update_assignment(
    project_id: str,
    assignment_id: str,
    request: Request,
    db: Session = Depends(get_db),
):
    """
    Update an assignment's date window and/or notes.

    Common use case: backdate a deployment so events emitted before the
    operator created the assignment in terra-view (e.g. a unit that was
    physically deployed in December but only recorded in the system today)
    get correctly attributed to the location.

    Accepts JSON body with optional fields:
      - assigned_at:    ISO datetime (or empty string to leave unchanged)
      - assigned_until: ISO datetime, or null/"" to mark indefinite (active)
      - notes:          string

    Sets `status` to "active" when assigned_until is cleared, "completed"
    when it's set in the past.
    """
    assignment = db.query(UnitAssignment).filter_by(
        id=assignment_id,
        project_id=project_id,
    ).first()

    if not assignment:
        raise HTTPException(status_code=404, detail="Assignment not found")

    try:
        payload = await request.json()
    except Exception:
        raise HTTPException(status_code=400, detail="Invalid JSON body")

    # Parse new values (None = unchanged, explicit None/"" for assigned_until = clear)
    new_assigned_at = assignment.assigned_at
    new_assigned_until = assignment.assigned_until
    new_notes = assignment.notes

    if "assigned_at" in payload:
        raw = payload["assigned_at"]
        if raw is None or raw == "":
            raise HTTPException(
                status_code=400,
                detail="assigned_at is required; cannot be cleared.",
            )
        try:
            # Accept "YYYY-MM-DDTHH:MM" from datetime-local inputs or full ISO.
            new_assigned_at = datetime.fromisoformat(raw)
        except (TypeError, ValueError):
            raise HTTPException(
                status_code=400,
                detail=f"Invalid assigned_at datetime: {raw!r}",
            )

    if "assigned_until" in payload:
        raw = payload["assigned_until"]
        if raw is None or raw == "":
            new_assigned_until = None
        else:
            try:
                new_assigned_until = datetime.fromisoformat(raw)
            except (TypeError, ValueError):
                raise HTTPException(
                    status_code=400,
                    detail=f"Invalid assigned_until datetime: {raw!r}",
                )

    if "notes" in payload:
        raw = payload["notes"]
        new_notes = (raw or "").strip() or None

    # Validation: end must be after start if both set.
    if new_assigned_until is not None and new_assigned_until <= new_assigned_at:
        raise HTTPException(
            status_code=400,
            detail="assigned_until must be after assigned_at.",
        )

    # Sanity: reject creating an overlap with another assignment of the SAME
    # unit at the SAME location.  Different units at the same location can
    # legitimately overlap during a swap window (rare but valid).
    new_end_for_overlap = new_assigned_until or datetime.utcnow()
    overlapping = (
        db.query(UnitAssignment)
        .filter(UnitAssignment.location_id == assignment.location_id)
        .filter(UnitAssignment.unit_id == assignment.unit_id)
        .filter(UnitAssignment.id != assignment.id)
        .all()
    )
    for other in overlapping:
        other_start = other.assigned_at
        other_end = other.assigned_until or datetime.utcnow()
        if new_assigned_at < other_end and new_end_for_overlap > other_start:
            raise HTTPException(
                status_code=400,
                detail=(
                    f"This window overlaps with another assignment for the "
                    f"same unit ({other.assigned_at:%Y-%m-%d} → "
                    f"{other.assigned_until and other.assigned_until.strftime('%Y-%m-%d') or 'present'})."
                ),
            )

    # Capture change description for audit log BEFORE mutating.
    old_start = assignment.assigned_at.isoformat() if assignment.assigned_at else None
    old_end   = assignment.assigned_until.isoformat() if assignment.assigned_until else "active"
    new_start = new_assigned_at.isoformat() if new_assigned_at else None
    new_end   = new_assigned_until.isoformat() if new_assigned_until else "active"

    # Apply.
    assignment.assigned_at = new_assigned_at
    assignment.assigned_until = new_assigned_until
    assignment.notes = new_notes
    assignment.status = "completed" if new_assigned_until is not None else "active"

    if old_start != new_start or old_end != new_end:
        _record_assignment_history(
            db,
            unit_id=assignment.unit_id,
            change_type="assignment_updated",
            old_value=f"{old_start} → {old_end}",
            new_value=f"{new_start} → {new_end}",
            notes=new_notes,
        )

    db.commit()
    db.refresh(assignment)

    return {
        "success": True,
        "assignment": {
            "id":             assignment.id,
            "unit_id":        assignment.unit_id,
            "location_id":    assignment.location_id,
            "assigned_at":    assignment.assigned_at.isoformat() if assignment.assigned_at else None,
            "assigned_until": assignment.assigned_until.isoformat() if assignment.assigned_until else None,
            "status":         assignment.status,
            "notes":          assignment.notes,
        },
    }


@router.delete("/assignments/{assignment_id}")
async def delete_assignment(
    project_id: str,
    assignment_id: str,
    db: Session = Depends(get_db),
):
    """
    Hard-delete an assignment record.

    Use case: operator clicked Assign by mistake (or 8 times in a row) and
    wants the bogus records gone — not just closed with an `assigned_until`
    timestamp.  The standard close-via-unassign path is for legitimate
    deployments that ended; this is for mis-clicks that never actually
    happened.

    Safety:
      - Refuses if any MonitoringSession exists for the same (unit, location)
        within this assignment's window — that suggests the deployment was
        real, and the operator should use unassign instead.
      - Refuses if the assignment is the ONLY active assignment for a unit
        currently shown as deployed AND a recording session is in progress.

    Audit:
      - Records UnitHistory `assignment_deleted` so the unit's deployment
        timeline shows the deletion happened (even though the row itself
        is gone).
    """
    assignment = db.query(UnitAssignment).filter_by(
        id=assignment_id,
        project_id=project_id,
    ).first()

    if not assignment:
        raise HTTPException(status_code=404, detail="Assignment not found")

    # Safety: is there a real recording history for this (unit, location)
    # within the assignment's time window?  If so, this isn't a mis-click —
    # the operator should close it via unassign, not delete it.
    window_start = assignment.assigned_at
    window_end   = assignment.assigned_until or datetime.utcnow()
    real_sessions = db.query(MonitoringSession).filter(
        and_(
            MonitoringSession.location_id == assignment.location_id,
            MonitoringSession.unit_id == assignment.unit_id,
            MonitoringSession.start_time >= window_start,
            MonitoringSession.start_time <= window_end,
        )
    ).count()

    if real_sessions > 0:
        raise HTTPException(
            status_code=400,
            detail=(
                f"Cannot delete this assignment — {real_sessions} monitoring "
                f"session(s) were recorded under it.  Use Unassign to close "
                f"the window instead, which preserves the audit trail."
            ),
        )

    # Resolve location name for audit log before deletion.
    location = db.query(MonitoringLocation).filter_by(
        id=assignment.location_id
    ).first()
    location_label = location.name if location else assignment.location_id

    _record_assignment_history(
        db,
        unit_id=assignment.unit_id,
        change_type="assignment_deleted",
        old_value=f"{location_label} ({assignment.assigned_at:%Y-%m-%d} → "
                  f"{assignment.assigned_until and assignment.assigned_until.strftime('%Y-%m-%d') or 'active'})",
        new_value="deleted",
        notes=(
            "Assignment row removed — created in error or accidental duplicate."
        ),
    )

    db.delete(assignment)
    db.commit()

    return {
        "success": True,
        "message": "Assignment deleted.",
    }


@router.post("/locations/{location_id}/swap")
async def swap_unit_on_location(
    project_id: str,
    location_id: str,
    request: Request,
    db: Session = Depends(get_db),
):
    """
    Swap the unit assigned to a vibration monitoring location.
    Ends the current active assignment (if any), creates a new one,
    and optionally updates modem pairing on the seismograph.
    Works for first-time assignments too (no current assignment = just create).
    """
    location = db.query(MonitoringLocation).filter_by(
        id=location_id,
        project_id=project_id,
    ).first()
    if not location:
        raise HTTPException(status_code=404, detail="Location not found")

    form_data = await request.form()
    unit_id = form_data.get("unit_id")
    modem_id = form_data.get("modem_id") or None
    notes = form_data.get("notes") or None

    if not unit_id:
        raise HTTPException(status_code=400, detail="unit_id is required")

    # Validate new unit
    unit = db.query(RosterUnit).filter_by(id=unit_id).first()
    if not unit:
        raise HTTPException(status_code=404, detail="Unit not found")

    expected_device_type = "slm" if location.location_type == "sound" else "seismograph"
    if unit.device_type != expected_device_type:
        raise HTTPException(
            status_code=400,
            detail=f"Unit type '{unit.device_type}' does not match location type '{location.location_type}'",
        )

    # End current active assignment if one exists (active = assigned_until IS NULL)
    current = db.query(UnitAssignment).filter(
        and_(
            UnitAssignment.location_id == location_id,
            UnitAssignment.assigned_until == None,
        )
    ).first()
    if current:
        current.assigned_until = datetime.utcnow()
        current.status = "completed"
        # If the swap is replacing a different unit, that unit's deployment ended.
        if current.unit_id != unit_id:
            _record_assignment_history(
                db,
                unit_id=current.unit_id,
                change_type="assignment_swapped",
                old_value=location.name,
                new_value=f"swapped out → {unit_id}",
                notes=notes,
            )

    # Create new assignment
    new_assignment = UnitAssignment(
        id=str(uuid.uuid4()),
        unit_id=unit_id,
        location_id=location_id,
        project_id=project_id,
        device_type=unit.device_type,
        assigned_until=None,
        status="active",
        notes=notes,
    )
    db.add(new_assignment)
    _record_assignment_history(
        db,
        unit_id=unit_id,
        change_type="assignment_swapped" if (current and current.unit_id != unit_id) else "assignment_created",
        new_value=f"{location.name} (project: {location.project_id})",
        notes=notes,
    )

    # Update modem pairing on the seismograph if modem provided
    if modem_id:
        modem = db.query(RosterUnit).filter_by(id=modem_id, device_type="modem").first()
        if not modem:
            raise HTTPException(status_code=404, detail=f"Modem '{modem_id}' not found")
        unit.deployed_with_modem_id = modem_id
        modem.deployed_with_unit_id = unit_id
    else:
        # Clear modem pairing if not provided
        unit.deployed_with_modem_id = None

    db.commit()

    return JSONResponse({
        "success": True,
        "assignment_id": new_assignment.id,
        "message": f"Unit '{unit_id}' assigned to '{location.name}'" + (f" with modem '{modem_id}'" if modem_id else ""),
    })


# ============================================================================
# Available Units for Assignment
# ============================================================================

@router.get("/available-modems", response_class=JSONResponse)
async def get_available_modems(
    project_id: str,
    db: Session = Depends(get_db),
):
    """
    Get all deployed, non-retired modems for the modem assignment dropdown.
    """
    modems = db.query(RosterUnit).filter(
        and_(
            RosterUnit.device_type == "modem",
            RosterUnit.deployed == True,
            RosterUnit.retired == False,
        )
    ).order_by(RosterUnit.id).all()

    return [
        {
            "id": m.id,
            "hardware_model": m.hardware_model,
            "ip_address": m.ip_address,
        }
        for m in modems
    ]


@router.get("/available-units", response_class=JSONResponse)
async def get_available_units(
    project_id: str,
    location_type: str = Query(...),
    db: Session = Depends(get_db),
):
    """
    Get list of available units for assignment to a location.
    Filters by device type matching the location type.
    """
    # Determine required device type
    required_device_type = "slm" if location_type == "sound" else "seismograph"

    # Get all units of the required type that are deployed and not retired
    all_units = db.query(RosterUnit).filter(
        and_(
            RosterUnit.device_type == required_device_type,
            RosterUnit.deployed == True,
            RosterUnit.retired == False,
        )
    ).all()

    # Filter out units that already have active assignments (active = assigned_until IS NULL)
    assigned_unit_ids = db.query(UnitAssignment.unit_id).filter(
        UnitAssignment.assigned_until == None
    ).distinct().all()
    assigned_unit_ids = [uid[0] for uid in assigned_unit_ids]

    available_units = [
        {
            "id": unit.id,
            "device_type": unit.device_type,
            "location": unit.address or unit.location,
            "model": unit.slm_model if unit.device_type == "slm" else unit.unit_type,
        }
        for unit in all_units
        if unit.id not in assigned_unit_ids
    ]

    return available_units


# ============================================================================
# NRL-specific endpoints for detail page
# ============================================================================

@router.get("/nrl/{location_id}/sessions", response_class=HTMLResponse)
async def get_nrl_sessions(
    project_id: str,
    location_id: str,
    request: Request,
    db: Session = Depends(get_db),
):
    """
    Get monitoring sessions for a specific NRL.
    Returns HTML partial with session list.
    """
    sessions = db.query(MonitoringSession).filter_by(
        location_id=location_id
    ).order_by(MonitoringSession.started_at.desc()).all()

    # Enrich with unit details
    sessions_data = []
    for session in sessions:
        unit = None
        if session.unit_id:
            unit = db.query(RosterUnit).filter_by(id=session.unit_id).first()

        sessions_data.append({
            "session": session,
            "unit": unit,
        })

    return templates.TemplateResponse("partials/projects/session_list.html", {
        "request": request,
        "project_id": project_id,
        "location_id": location_id,
        "sessions": sessions_data,
    })


@router.get("/vibration_summary", response_class=HTMLResponse)
async def get_project_vibration_summary(
    project_id: str,
    request: Request,
    from_dt: Optional[datetime] = Query(None),
    to_dt: Optional[datetime] = Query(None),
    db: Session = Depends(get_db),
):
    """
    Render a small HTML partial summarising vibration-event activity
    across every vibration MonitoringLocation in the project.

    Returned to the Vibration tab of the project detail page via HTMX.
    Fans out concurrently across all locations (which in turn fan out
    across each location's UnitAssignment windows).  Total queries to
    SFM = sum of assignments across the project.

    404 if the project doesn't exist.  Empty-state partial if the
    project has no vibration locations.
    """
    project = db.query(Project).filter_by(id=project_id).first()
    if not project:
        raise HTTPException(status_code=404, detail="Project not found.")

    from backend.services.sfm_events import vibration_summary_for_project

    summary = await vibration_summary_for_project(
        db, project_id, from_dt=from_dt, to_dt=to_dt
    )

    return templates.TemplateResponse(
        "partials/projects/vibration_summary.html",
        {
            "request":    request,
            "project_id": project_id,
            "summary":    summary,
        },
    )


@router.get("/locations/{location_id}/events", response_class=JSONResponse)
async def get_location_events(
    project_id: str,
    location_id: str,
    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 recorded at this monitoring location.

    Fans out the location's UnitAssignment rows (every seismograph ever
    assigned to this location, active + closed), queries SFM /db/events
    for each (serial, time-window) pair concurrently, and unions the
    results.

    Sound (SLM) locations return an empty payload — SFM events are
    seismograph-only.
    """
    location = db.query(MonitoringLocation).filter_by(id=location_id).first()
    if not location:
        raise HTTPException(status_code=404, detail="Location not found.")
    if location.project_id != project_id:
        raise HTTPException(
            status_code=404,
            detail="Location does not belong to this project.",
        )

    # SLM locations don't have SFM events — return an empty payload rather
    # than 404 so the frontend can render an empty state gracefully.
    if location.location_type != "vibration":
        return {
            "events":           [],
            "count":             0,
            "stats": {
                "event_count":         0,
                "peak_pvs":            None,
                "peak_pvs_at":         None,
                "peak_pvs_serial":     None,
                "last_event":          None,
                "false_trigger_count": 0,
            },
            "assignments_used": [],
            "location_type":    location.location_type,
        }

    from backend.services.sfm_events import events_for_location

    result = await events_for_location(
        db,
        location_id,
        from_dt=from_dt,
        to_dt=to_dt,
        false_trigger=false_trigger,
        limit=limit,
    )
    result["location_type"] = location.location_type
    return result


@router.get("/nrl/{location_id}/files", response_class=HTMLResponse)
async def get_nrl_files(
    project_id: str,
    location_id: str,
    request: Request,
    db: Session = Depends(get_db),
):
    """
    Get data files for a specific NRL.
    Returns HTML partial with file list.
    """
    # Join DataFile with MonitoringSession to filter by location_id
    files = db.query(DataFile).join(
        MonitoringSession,
        DataFile.session_id == MonitoringSession.id
    ).filter(
        MonitoringSession.location_id == location_id
    ).order_by(DataFile.created_at.desc()).all()

    # Enrich with session details
    files_data = []
    for file in files:
        session = None
        if file.session_id:
            session = db.query(MonitoringSession).filter_by(id=file.session_id).first()

        files_data.append({
            "file": file,
            "session": session,
        })

    return templates.TemplateResponse("partials/projects/file_list.html", {
        "request": request,
        "project_id": project_id,
        "location_id": location_id,
        "files": files_data,
    })


# ============================================================================
# Manual SD Card Data Upload
# ============================================================================

def _parse_rnh(content: bytes) -> dict:
    """
    Parse a Rion .rnh metadata file (INI-style with [Section] headers).
    Returns a dict of key metadata fields.
    """
    result = {}
    try:
        text = content.decode("utf-8", errors="replace")
        for line in text.splitlines():
            line = line.strip()
            if not line or line.startswith("["):
                continue
            if "," in line:
                key, _, value = line.partition(",")
                key = key.strip()
                value = value.strip()
                if key == "Serial Number":
                    result["serial_number"] = value
                elif key == "Store Name":
                    result["store_name"] = value
                elif key == "Index Number":
                    result["index_number"] = value
                elif key == "Measurement Start Time":
                    result["start_time_str"] = value
                elif key == "Measurement Stop Time":
                    result["stop_time_str"] = value
                elif key == "Total Measurement Time":
                    result["total_time_str"] = value
    except Exception:
        pass
    return result


def _parse_rnh_datetime(s: str):
    """Parse RNH datetime string: '2026/02/17 19:00:19' -> datetime"""
    from datetime import datetime
    if not s:
        return None
    try:
        return datetime.strptime(s.strip(), "%Y/%m/%d %H:%M:%S")
    except Exception:
        return None


def _classify_file(filename: str) -> str:
    """Classify a file by name into a DataFile file_type."""
    name = filename.lower()
    if name.endswith(".rnh"):
        return "log"
    if name.endswith(".rnd"):
        return "measurement"
    if name.endswith(".zip"):
        return "archive"
    return "data"


@router.post("/nrl/{location_id}/upload-data")
async def upload_nrl_data(
    project_id: str,
    location_id: str,
    db: Session = Depends(get_db),
    files: list[UploadFile] = File(...),
):
    """
    Manually upload SD card data for an offline NRL.

    Accepts either:
    - A single .zip file (the Auto_#### folder zipped) — auto-extracted
    - Multiple .rnd / .rnh files selected directly from the SD card folder

    Creates a MonitoringSession from .rnh metadata and DataFile records
    for each measurement file. No unit assignment required.
    """
    from datetime import datetime

    # Verify project and location exist
    project = db.query(Project).filter_by(id=project_id).first()
    _require_module(project, "sound_monitoring", db)

    location = db.query(MonitoringLocation).filter_by(
        id=location_id, project_id=project_id
    ).first()
    if not location:
        raise HTTPException(status_code=404, detail="Location not found")

    # --- Step 1: Normalize to (filename, bytes) list ---
    file_entries: list[tuple[str, bytes]] = []

    if len(files) == 1 and files[0].filename.lower().endswith(".zip"):
        raw = await files[0].read()
        try:
            with zipfile.ZipFile(io.BytesIO(raw)) as zf:
                for info in zf.infolist():
                    if info.is_dir():
                        continue
                    name = Path(info.filename).name  # strip folder path
                    if not name:
                        continue
                    file_entries.append((name, zf.read(info)))
        except zipfile.BadZipFile:
            raise HTTPException(status_code=400, detail="Uploaded file is not a valid ZIP archive.")
    else:
        for uf in files:
            data = await uf.read()
            file_entries.append((uf.filename, data))

    if not file_entries:
        raise HTTPException(status_code=400, detail="No usable files found in upload.")

    # --- Step 1b: Filter to only relevant files ---
    # Keep: .rnh (metadata) and measurement .rnd files
    #   NL-43 generates two .rnd types: _Leq_ (15-min averages, wanted) and _Lp_ (1-sec granular, skip)
    #   AU2 (NL-23/older Rion) generates a single Au2_####.rnd per session — always keep those
    # Drop: _Lp_ .rnd, .xlsx, .mp3, and anything else
    def _is_wanted(fname: str) -> bool:
        n = fname.lower()
        if n.endswith(".rnh"):
            return True
        if n.endswith(".rnd"):
            if "_leq_" in n:        # NL-43 Leq file
                return True
            if n.startswith("au2_"): # AU2 format (NL-23) — always Leq equivalent
                return True
            if "_lp" not in n and "_leq_" not in n:
                # Unknown .rnd format — include it so we don't silently drop data
                return True
        return False

    file_entries = [(fname, fbytes) for fname, fbytes in file_entries if _is_wanted(fname)]

    if not file_entries:
        raise HTTPException(status_code=400, detail="No usable .rnd or .rnh files found. Expected NL-43 _Leq_ files or AU2 format .rnd files.")

    # --- Step 2: Find and parse .rnh metadata ---
    rnh_meta = {}
    for fname, fbytes in file_entries:
        if fname.lower().endswith(".rnh"):
            rnh_meta = _parse_rnh(fbytes)
            break

    # RNH files store local time (no UTC offset).  Use local values for period
    # classification / label generation, then convert to UTC for DB storage so
    # the local_datetime Jinja filter displays the correct time.
    started_at_local = _parse_rnh_datetime(rnh_meta.get("start_time_str")) or datetime.utcnow()
    stopped_at_local = _parse_rnh_datetime(rnh_meta.get("stop_time_str"))

    started_at = local_to_utc(started_at_local)
    stopped_at = local_to_utc(stopped_at_local) if stopped_at_local else None

    duration_seconds = None
    if started_at and stopped_at:
        duration_seconds = int((stopped_at - started_at).total_seconds())

    store_name = rnh_meta.get("store_name", "")
    serial_number = rnh_meta.get("serial_number", "")
    index_number = rnh_meta.get("index_number", "")

    # --- Step 3: Create MonitoringSession ---
    # Use local times for period/label so classification reflects the clock at the site.
    period_type = _derive_period_type(started_at_local) if started_at_local else None
    session_label = _build_session_label(started_at_local, location.name, period_type) if started_at_local else None

    session_id = str(uuid.uuid4())
    monitoring_session = MonitoringSession(
        id=session_id,
        project_id=project_id,
        location_id=location_id,
        unit_id=None,
        session_type="sound",
        started_at=started_at,
        stopped_at=stopped_at,
        duration_seconds=duration_seconds,
        status="completed",
        session_label=session_label,
        period_type=period_type,
        session_metadata=json.dumps({
            "source": "manual_upload",
            "store_name": store_name,
            "serial_number": serial_number,
            "index_number": index_number,
        }),
    )
    db.add(monitoring_session)
    db.commit()
    db.refresh(monitoring_session)

    # --- Step 4: Write files to disk and create DataFile records ---
    output_dir = Path("data/Projects") / project_id / session_id
    output_dir.mkdir(parents=True, exist_ok=True)

    leq_count = 0
    lp_count = 0
    metadata_count = 0
    files_imported = 0

    for fname, fbytes in file_entries:
        file_type = _classify_file(fname)
        fname_lower = fname.lower()

        # Track counts for summary
        if fname_lower.endswith(".rnd"):
            if "_leq_" in fname_lower:
                leq_count += 1
            elif "_lp" in fname_lower:
                lp_count += 1
        elif fname_lower.endswith(".rnh"):
            metadata_count += 1

        # Write to disk
        dest = output_dir / fname
        dest.write_bytes(fbytes)

        # Compute checksum
        checksum = hashlib.sha256(fbytes).hexdigest()

        # Store relative path from data/ dir
        rel_path = str(dest.relative_to("data"))

        data_file = DataFile(
            id=str(uuid.uuid4()),
            session_id=session_id,
            file_path=rel_path,
            file_type=file_type,
            file_size_bytes=len(fbytes),
            downloaded_at=datetime.utcnow(),
            checksum=checksum,
            file_metadata=json.dumps({
                "source": "manual_upload",
                "original_filename": fname,
                "store_name": store_name,
            }),
        )
        db.add(data_file)
        files_imported += 1

    db.commit()

    return {
        "success": True,
        "session_id": session_id,
        "files_imported": files_imported,
        "leq_files": leq_count,
        "lp_files": lp_count,
        "metadata_files": metadata_count,
        "store_name": store_name,
        "started_at": started_at.isoformat() if started_at else None,
        "stopped_at": stopped_at.isoformat() if stopped_at else None,
    }


# ============================================================================
# NRL Live Status (connected NRLs only)
# ============================================================================

@router.get("/nrl/{location_id}/live-status", response_class=HTMLResponse)
async def get_nrl_live_status(
    project_id: str,
    location_id: str,
    request: Request,
    db: Session = Depends(get_db),
):
    """
    Fetch cached status from SLMM for the unit assigned to this NRL and
    return a compact HTML status card. Used in the NRL overview tab for
    connected NRLs. Gracefully shows an offline message if SLMM is unreachable.
    Sound Monitoring projects only.
    """
    import os
    import httpx

    _require_module(db.query(Project).filter_by(id=project_id).first(), "sound_monitoring", db)

    # Find the assigned unit (active = assigned_until IS NULL)
    assignment = db.query(UnitAssignment).filter(
        and_(
            UnitAssignment.location_id == location_id,
            UnitAssignment.assigned_until == None,
        )
    ).first()

    if not assignment:
        return templates.TemplateResponse("partials/projects/nrl_live_status.html", {
            "request": request,
            "status": None,
            "error": "No unit assigned",
        })

    unit = db.query(RosterUnit).filter_by(id=assignment.unit_id).first()
    if not unit:
        return templates.TemplateResponse("partials/projects/nrl_live_status.html", {
            "request": request,
            "status": None,
            "error": "Assigned unit not found",
        })

    slmm_base = os.getenv("SLMM_BASE_URL", "http://localhost:8100")
    status_data = None
    error_msg = None

    try:
        async with httpx.AsyncClient(timeout=5.0) as client:
            resp = await client.get(f"{slmm_base}/api/nl43/{unit.id}/status")
            if resp.status_code == 200:
                status_data = resp.json()
            else:
                error_msg = f"SLMM returned {resp.status_code}"
    except Exception as e:
        error_msg = "SLMM unreachable"

    return templates.TemplateResponse("partials/projects/nrl_live_status.html", {
        "request": request,
        "unit": unit,
        "status": status_data,
        "error": error_msg,
    })