"""Computers plugin API endpoints."""

from flask import Blueprint, request
from flask_jwt_extended import jwt_required

from shopdb.api import db, Asset, AssetType, OperatingSystem, Application, AuditLog, Communication, CommunicationType, Setting, success_response, error_response, paginated_response, ErrorCodes, get_pagination_params, paginate_query

from ..models import Computer, ComputerType, ComputerInstalledApp, AccessProtocol, ComputerAccess

from shopdb.api import require_permission, apply_import_timestamps

computers_bp = Blueprint('computers', __name__)


# =============================================================================
# Computer Types
# =============================================================================

@computers_bp.route('/types', methods=['GET'])
@jwt_required(optional=True)
def list_computer_types():
    """List all computer types."""
    page, per_page = get_pagination_params(request)

    query = ComputerType.query

    if request.args.get('active', 'true').lower() != 'false':
        query = query.filter(ComputerType.isactive == True)

    if search := request.args.get('search'):
        query = query.filter(ComputerType.computertype.ilike(f'%{search}%'))

    query = query.order_by(ComputerType.computertype)

    items, total = paginate_query(query, page, per_page)
    data = [t.to_dict() for t in items]

    return paginated_response(data, page, per_page, total)


@computers_bp.route('/types/<int:type_id>', methods=['GET'])
@jwt_required(optional=True)
def get_computer_type(type_id: int):
    """Get a single computer type."""
    t = db.session.get(ComputerType, type_id)

    if not t:
        return error_response(
            ErrorCodes.NOT_FOUND,
            f'Computer type with ID {type_id} not found',
            http_code=404
        )

    return success_response(t.to_dict())


@computers_bp.route('/types', methods=['POST'])
@jwt_required()
@require_permission('computers.create')
def create_computer_type():
    """Create a new computer type."""
    data = request.get_json()

    if not data or not data.get('computertype'):
        return error_response(ErrorCodes.VALIDATION_ERROR, 'computertype is required')

    existing = ComputerType.query.filter_by(computertype=data['computertype']).first()
    if existing:
        if not existing.isactive:
            # Adding a name that matches a deactivated type revives it.
            existing.isactive = True
            for key in ('description', 'icon', 'color'):
                if data.get(key) is not None:
                    setattr(existing, key, data[key])
            db.session.commit()
            return success_response(existing.to_dict(), message='Reactivated existing computer type')
        return error_response(
            ErrorCodes.CONFLICT,
            f"Computer type '{data['computertype']}' already exists",
            http_code=409
        )

    t = ComputerType(
        computertype=data['computertype'],
        description=data.get('description'),
        icon=data.get('icon'), color=data.get('color')
    )

    db.session.add(t)
    db.session.commit()

    return success_response(t.to_dict(), message='Computer type created', http_code=201)


@computers_bp.route('/types/<int:type_id>', methods=['PUT'])
@jwt_required()
@require_permission('computers.edit')
def update_computer_type(type_id: int):
    """Update a computer type."""
    t = db.session.get(ComputerType, type_id)

    if not t:
        return error_response(
            ErrorCodes.NOT_FOUND,
            f'Computer type with ID {type_id} not found',
            http_code=404
        )

    data = request.get_json()
    if not data:
        return error_response(ErrorCodes.VALIDATION_ERROR, 'No data provided')

    if 'computertype' in data and data['computertype'] != t.computertype:
        if ComputerType.query.filter_by(computertype=data['computertype']).first():
            return error_response(
                ErrorCodes.CONFLICT,
                f"Computer type '{data['computertype']}' already exists",
                http_code=409
            )

    for key in ['computertype', 'description', 'icon', 'color', 'isactive']:
        if key in data:
            setattr(t, key, data[key])

    db.session.commit()
    return success_response(t.to_dict(), message='Computer type updated')


@computers_bp.route('/types/<int:type_id>', methods=['DELETE'])
@jwt_required()
@require_permission('computers.delete')
def delete_computer_type(type_id: int):
    """Delete a computer type. Refused if any PC still uses it."""
    t = db.session.get(ComputerType, type_id)
    if not t:
        return error_response(ErrorCodes.NOT_FOUND, 'Computer type not found', http_code=404)
    inuse = Computer.query.filter_by(computertypeid=type_id).count()
    if inuse:
        return error_response(ErrorCodes.CONFLICT,
                              f"Cannot delete: {inuse} PC(s) still use this type", http_code=409)
    db.session.delete(t)
    db.session.commit()
    return success_response(message='Computer type deleted')


# =============================================================================
# Access protocol catalog (VNC / WinRM / RDP / ...) - admin-managed
# =============================================================================

@computers_bp.route('/protocols', methods=['GET'])
@jwt_required(optional=True)
def list_protocols():
    """List access protocols. ?active=false includes disabled ones."""
    query = AccessProtocol.query
    if request.args.get('active', 'true').lower() != 'false':
        query = query.filter(AccessProtocol.isactive == True)
    protocols = query.order_by(AccessProtocol.name).all()
    return success_response([p.to_dict() for p in protocols])


@computers_bp.route('/protocols', methods=['POST'])
@jwt_required()
@require_permission('computers.edit')
def create_protocol():
    data = request.get_json() or {}
    if not (data.get('name') and data.get('scheme') and data.get('linktemplate')):
        return error_response(ErrorCodes.VALIDATION_ERROR, 'name, scheme and linktemplate are required')
    if AccessProtocol.query.filter_by(name=data['name']).first():
        return error_response(ErrorCodes.CONFLICT, f"Protocol '{data['name']}' already exists", http_code=409)
    p = AccessProtocol(
        name=data['name'],
        scheme=data['scheme'],
        defaultport=data.get('defaultport') or None,
        linktemplate=data['linktemplate'],
        isactive=data.get('isactive', True),
    )
    db.session.add(p)
    db.session.commit()
    return success_response(p.to_dict(), message='Protocol created', http_code=201)


@computers_bp.route('/protocols/<int:protocol_id>', methods=['PUT', 'PATCH'])
@jwt_required()
@require_permission('computers.edit')
def update_protocol(protocol_id):
    p = db.session.get(AccessProtocol, protocol_id)
    if not p:
        return error_response(ErrorCodes.NOT_FOUND, 'Protocol not found', http_code=404)
    data = request.get_json() or {}
    for field in ('name', 'scheme', 'linktemplate'):
        if data.get(field):
            setattr(p, field, data[field])
    if 'defaultport' in data:
        p.defaultport = data['defaultport'] or None
    if 'isactive' in data:
        p.isactive = bool(data['isactive'])
    db.session.commit()
    return success_response(p.to_dict(), message='Protocol updated')


@computers_bp.route('/protocols/<int:protocol_id>', methods=['DELETE'])
@jwt_required()
@require_permission('computers.edit')
def delete_protocol(protocol_id):
    p = db.session.get(AccessProtocol, protocol_id)
    if not p:
        return error_response(ErrorCodes.NOT_FOUND, 'Protocol not found', http_code=404)
    # If any PC still references it, deactivate rather than hard-delete.
    if ComputerAccess.query.filter_by(protocolid=protocol_id).first():
        p.isactive = False
        db.session.commit()
        return success_response(message='Protocol is in use; deactivated instead of deleted')
    db.session.delete(p)
    db.session.commit()
    return success_response(message='Protocol deleted')


def _pc_access_domain():
    # Contract-pure read of the pc_access_domain setting (no core.api import).
    row = Setting.query.filter_by(key='pc_access_domain').first()
    return ((row.value if row else '') or '').strip()


def _computer_access_links(comp, domain=None):
    """Resolved remote-access links for a computer: each enabled protocol's
    template filled with the PC hostname joined to the pc_access_domain setting.
    A hostname that is already an FQDN (has a dot) is used as-is. Pass domain
    when calling in a loop to avoid one settings lookup per computer."""
    if domain is None:
        domain = _pc_access_domain()
    hostname = (comp.hostname or '').strip()
    if not hostname:
        host = ''
    elif '.' in hostname or not domain:
        host = hostname
    else:
        host = f"{hostname}.{domain}"

    links = []
    for am in comp.accessmethods:
        protocol = am.protocol
        if not (am.isactive and protocol and protocol.isactive):
            continue
        port = am.portoverride or protocol.defaultport
        link = None
        if host:
            try:
                link = protocol.linktemplate.format(
                    host=host,
                    port=(port if port is not None else ''),
                    scheme=protocol.scheme,
                )
            except (KeyError, IndexError, ValueError):
                link = None
        links.append({
            'id': am.id,
            'protocolid': protocol.protocolid,
            'name': protocol.name,
            'scheme': protocol.scheme,
            'port': port,
            'portoverride': am.portoverride,
            'link': link,
        })
    return links


def _sync_access_methods(comp, data):
    """Replace a computer's enabled protocols from data['accessmethods'] (a list
    of {protocolid, portoverride?}). No-op if the key is absent, so callers that
    don't touch access aren't affected."""
    if 'accessmethods' not in data:
        return
    desired = data.get('accessmethods') or []
    ComputerAccess.query.filter_by(computerid=comp.computerid).delete()
    seen = set()
    for m in desired:
        try:
            pid = int(m.get('protocolid'))
        except (TypeError, ValueError):
            continue
        if pid in seen:
            continue
        seen.add(pid)
        port = m.get('portoverride')
        try:
            port = int(port) if port not in (None, '') else None
        except (TypeError, ValueError):
            port = None
        db.session.add(ComputerAccess(
            computerid=comp.computerid,
            protocolid=pid,
            portoverride=port,
            isactive=True,
        ))


# =============================================================================
# Computers CRUD
# =============================================================================

@computers_bp.route('/display-kiosks', methods=['GET'])
@jwt_required(optional=True)
def list_display_kiosks():
    """Reporting display kiosks, for the Dashboard Defaults picker.

    Returns the computers whose type is the one gea-shopfloor-display maps to
    (default 'Kiosk'), each with its DERIVED FQDN (F<serial>.<domain>, domain
    from the display_fqdn_domain setting) so an admin picks a kiosk from a
    dropdown instead of typing an IP/FQDN. Keeps the same F<serial>.<domain>
    format as core derive_display_fqdn (duplicated to avoid a contract bump).
    """
    from ..pctypemap import pctype_mapping
    from shopdb.api import Setting

    display_type_name = pctype_mapping().get('gea-shopfloor-display', 'Kiosk')
    ctype = ComputerType.query.filter_by(computertype=display_type_name).first()
    if not ctype:
        return success_response([])
    domain = (Setting.get('display_fqdn_domain', 'device.geaerospace.net')
              or 'device.geaerospace.net').strip().strip('.')
    rows = (db.session.query(Computer).join(Asset)
            .filter(Computer.computertypeid == ctype.computertypeid,
                    Asset.isactive == True)
            .order_by(Computer.hostname).all())
    out = []
    for comp in rows:
        serial = (comp.asset.serialnumber or '').strip() if comp.asset else ''
        out.append({
            'computerid': comp.computerid,
            'hostname': comp.hostname,
            'serialnumber': serial or None,
            'fqdn': f'F{serial}.{domain}'.lower() if serial else None,
        })
    return success_response(out)


@computers_bp.route('', methods=['GET'])
@jwt_required(optional=True)
def list_computers():
    """
    List all computers with filtering and pagination.

    Query parameters:
    - page, per_page: Pagination
    - active: Filter by active status
    - search: Search by asset number, name, or hostname
    - type_id: Filter by computer type ID
    - os_id: Filter by operating system ID
    - location_id: Filter by location ID
    - businessunit_id: Filter by business unit ID
    - shopfloor: Filter by shopfloor flag (true/false)
    """
    page, per_page = get_pagination_params(request)

    # Join Computer with Asset
    query = db.session.query(Computer).join(Asset)

    # Active filter
    if request.args.get('active', 'true').lower() != 'false':
        query = query.filter(Asset.isactive == True)

    # Exact-match natural-key lookup for idempotent import (asset number).
    if exactassetnumber := request.args.get('assetnumber'):
        query = query.filter(Asset.assetnumber == exactassetnumber)

    # Search filter. Covers the type name too - it is a column in the list, so
    # searching 'Standard' must find the PCs of that type. Outer join so a PC
    # with no type still matches on its own fields.
    if search := request.args.get('search'):
        pattern = f'%{search}%'
        query = query.outerjoin(
            ComputerType, Computer.computertypeid == ComputerType.computertypeid
        ).filter(
            db.or_(
                Asset.assetnumber.ilike(pattern),
                Asset.name.ilike(pattern),
                Asset.serialnumber.ilike(pattern),
                Computer.hostname.ilike(pattern),
                ComputerType.computertype.ilike(pattern)
            )
        )

    # Computer type filter
    if type_id := request.args.get('typeid', request.args.get('type_id')):
        query = query.filter(Computer.computertypeid == int(type_id))

    # OS filter
    if os_id := request.args.get('osid', request.args.get('os_id')):
        query = query.filter(Computer.osid == int(os_id))

    # Location filter
    if location_id := request.args.get('locationid', request.args.get('location_id')):
        query = query.filter(Asset.locationid == int(location_id))

    # Business unit filter
    if bu_id := request.args.get('businessunitid', request.args.get('businessunit_id')):
        query = query.filter(Asset.businessunitid == int(bu_id))

    # Shopfloor filter (by the Shopfloor computer type)
    if shopfloor := request.args.get('shopfloor'):
        sf = ComputerType.query.filter_by(computertype='Shopfloor').first()
        sf_id = sf.computertypeid if sf else -1
        if shopfloor.lower() == 'true':
            query = query.filter(Computer.computertypeid == sf_id)
        else:
            query = query.filter(db.or_(Computer.computertypeid != sf_id,
                                        Computer.computertypeid.is_(None)))

    # Sorting
    sort_by = request.args.get('sort', 'hostname')
    sort_dir = request.args.get('dir', 'asc')

    if sort_by == 'hostname':
        col = Computer.hostname
    elif sort_by == 'assetnumber':
        col = Asset.assetnumber
    elif sort_by == 'name':
        col = Asset.name
    elif sort_by == 'lastreporteddate':
        col = Computer.lastreporteddate
    else:
        col = Computer.hostname

    query = query.order_by(col.desc() if sort_dir == 'desc' else col)

    items, total = paginate_query(query, page, per_page)

    # Build response with both asset and computer data
    data = []
    accessdomain = _pc_access_domain()
    for comp in items:
        item = comp.asset.to_dict() if comp.asset else {}
        item['computer'] = comp.to_dict()
        item['accessmethods'] = _computer_access_links(comp, domain=accessdomain)
        data.append(item)

    return paginated_response(data, page, per_page, total)


@computers_bp.route('/<int:computer_id>', methods=['GET'])
@jwt_required(optional=True)
def get_computer(computer_id: int):
    """Get a single computer with full details."""
    comp = db.session.get(Computer, computer_id)

    if not comp:
        return error_response(
            ErrorCodes.NOT_FOUND,
            f'Computer with ID {computer_id} not found',
            http_code=404
        )

    result = comp.asset.to_dict() if comp.asset else {}
    result['computer'] = comp.to_dict()
    result['communications'] = [
        c.to_dict() for c in
        Communication.query.filter_by(assetid=comp.assetid).all()
    ]
    result['accessmethods'] = _computer_access_links(comp)

    return success_response(result)


@computers_bp.route('/by-asset/<int:asset_id>', methods=['GET'])
@jwt_required(optional=True)
def get_computer_by_asset(asset_id: int):
    """Get computer data by asset ID."""
    comp = Computer.query.filter_by(assetid=asset_id).first()

    if not comp:
        return error_response(
            ErrorCodes.NOT_FOUND,
            f'Computer for asset {asset_id} not found',
            http_code=404
        )

    result = comp.asset.to_dict() if comp.asset else {}
    result['computer'] = comp.to_dict()

    return success_response(result)


@computers_bp.route('/by-hostname/<hostname>', methods=['GET'])
@jwt_required(optional=True)
def get_computer_by_hostname(hostname: str):
    """Get computer by hostname."""
    comp = Computer.query.filter_by(hostname=hostname).first()

    if not comp:
        return error_response(
            ErrorCodes.NOT_FOUND,
            f'Computer with hostname {hostname} not found',
            http_code=404
        )

    result = comp.asset.to_dict() if comp.asset else {}
    result['computer'] = comp.to_dict()

    return success_response(result)


@computers_bp.route('', methods=['POST'])
@jwt_required()
@require_permission('computers.create')
def create_computer():
    """
    Create new computer (creates both Asset and Computer records).

    Required fields:
    - assetnumber: Business identifier

    Optional fields:
    - name, serialnumber, statusid, locationid, businessunitid
    - computertypeid, hostname, osid
    - mapx, mapy, notes
    """
    data = request.get_json()

    if not data:
        return error_response(ErrorCodes.VALIDATION_ERROR, 'No data provided')

    if not data.get('assetnumber'):
        return error_response(ErrorCodes.VALIDATION_ERROR, 'assetnumber is required')

    # Check for duplicate assetnumber
    if Asset.query.filter_by(assetnumber=data['assetnumber']).first():
        return error_response(
            ErrorCodes.CONFLICT,
            f"Asset with number '{data['assetnumber']}' already exists",
            http_code=409
        )

    # Check for duplicate hostname
    if data.get('hostname'):
        if Computer.query.filter_by(hostname=data['hostname']).first():
            return error_response(
                ErrorCodes.CONFLICT,
                f"Computer with hostname '{data['hostname']}' already exists",
                http_code=409
            )

    # Get computer asset type
    computer_type = AssetType.query.filter_by(assettype='computer').first()
    if not computer_type:
        return error_response(
            ErrorCodes.INTERNAL_ERROR,
            'Computer asset type not found. Plugin may not be properly installed.',
            http_code=500
        )

    # Create the core asset
    asset = Asset(
        assetnumber=data['assetnumber'],
        name=data.get('name'),
        serialnumber=data.get('serialnumber'),
        gaugelabreference=data.get('gaugelabreference'),
        maintenancereference=data.get('maintenancereference'),
        assettypeid=computer_type.assettypeid,
        statusid=data.get('statusid', 1),
        locationid=data.get('locationid'),
        businessunitid=data.get('businessunitid'),
        mapx=data.get('mapx'),
        mapy=data.get('mapy'),
        notes=data.get('notes')
    )

    db.session.add(asset)
    db.session.flush()  # Get the assetid

    # Create the computer extension
    comp = Computer(
        assetid=asset.assetid,
        computertypeid=data.get('computertypeid'),
        hostname=data.get('hostname'),
        osid=data.get('osid'),
        vendorid=data.get('vendorid'),
        modelnumberid=data.get('modelnumberid'),
        loggedinuser=data.get('loggedinuser'),
        lastreporteddate=data.get('lastreporteddate'),
        lastboottime=data.get('lastboottime')
    )

    db.session.add(comp)
    db.session.flush()

    # Optional primary IP communication
    if data.get('ipaddress'):
        ip_comtype = CommunicationType.query.filter_by(comtype='IP').first()
        if ip_comtype:
            db.session.add(Communication(
                assetid=asset.assetid,
                comtypeid=ip_comtype.comtypeid,
                ipaddress=data['ipaddress'],
                isprimary=True,
            ))

    # Remote-access protocols
    _sync_access_methods(comp, data)

    # Preserve legacy timestamps in import mode (no-op otherwise)
    apply_import_timestamps(asset, data)

    # Audit log
    AuditLog.log('created', 'Computer', entityid=comp.computerid,
                 entityname=data.get('hostname') or data['assetnumber'])

    db.session.commit()

    result = asset.to_dict()
    result['computer'] = comp.to_dict()
    result['accessmethods'] = _computer_access_links(comp)

    return success_response(result, message='Computer created', http_code=201)


@computers_bp.route('/<int:computer_id>', methods=['PUT'])
@jwt_required()
@require_permission('computers.edit')
def update_computer(computer_id: int):
    """Update computer (both Asset and Computer records)."""
    comp = db.session.get(Computer, computer_id)

    if not comp:
        return error_response(
            ErrorCodes.NOT_FOUND,
            f'Computer with ID {computer_id} not found',
            http_code=404
        )

    data = request.get_json()
    if not data:
        return error_response(ErrorCodes.VALIDATION_ERROR, 'No data provided')

    asset = comp.asset

    # Check for conflicting assetnumber
    if 'assetnumber' in data and data['assetnumber'] != asset.assetnumber:
        if Asset.query.filter_by(assetnumber=data['assetnumber']).first():
            return error_response(
                ErrorCodes.CONFLICT,
                f"Asset with number '{data['assetnumber']}' already exists",
                http_code=409
            )

    # Check for conflicting hostname
    if 'hostname' in data and data['hostname'] != comp.hostname:
        existing = Computer.query.filter_by(hostname=data['hostname']).first()
        if existing and existing.computerid != computer_id:
            return error_response(
                ErrorCodes.CONFLICT,
                f"Computer with hostname '{data['hostname']}' already exists",
                http_code=409
            )

    # Track changes for audit log
    changes = {}

    # Update asset fields
    asset_fields = ['assetnumber', 'name', 'serialnumber', 'gaugelabreference',
                    'maintenancereference', 'statusid',
                    'locationid', 'businessunitid', 'mapx', 'mapy', 'notes', 'isactive']
    for key in asset_fields:
        if key in data:
            old_val = getattr(asset, key)
            new_val = data[key]
            if old_val != new_val:
                changes[key] = {'old': old_val, 'new': new_val}
            setattr(asset, key, data[key])

    # Update computer fields
    computer_fields = ['computertypeid', 'hostname', 'osid', 'vendorid',
                       'modelnumberid', 'loggedinuser', 'lastreporteddate',
                       'lastboottime']
    for key in computer_fields:
        if key in data:
            old_val = getattr(comp, key)
            new_val = data[key]
            if old_val != new_val:
                changes[key] = {'old': old_val, 'new': new_val}
            setattr(comp, key, data[key])

    # Upsert the primary IP communication so a single PUT covers it
    if 'ipaddress' in data:
        ip = (data.get('ipaddress') or '').strip()
        primary = Communication.query.filter_by(
            assetid=asset.assetid, isprimary=True).first()
        if ip:
            if primary:
                primary.ipaddress = ip
            else:
                ip_comtype = CommunicationType.query.filter_by(comtype='IP').first()
                if ip_comtype:
                    db.session.add(Communication(
                        assetid=asset.assetid, comtypeid=ip_comtype.comtypeid,
                        ipaddress=ip, isprimary=True))
        elif primary:
            primary.ipaddress = None

    # Remote-access protocols
    _sync_access_methods(comp, data)

    # Audit log if there were changes
    if changes:
        AuditLog.log('updated', 'Computer', entityid=comp.computerid,
                     entityname=comp.hostname or asset.assetnumber, changes=changes)

    apply_import_timestamps(asset, data)
    db.session.commit()

    result = asset.to_dict()
    result['computer'] = comp.to_dict()
    result['accessmethods'] = _computer_access_links(comp)

    return success_response(result, message='Computer updated')


@computers_bp.route('/<int:computer_id>', methods=['DELETE'])
@jwt_required()
@require_permission('computers.delete')
def delete_computer(computer_id: int):
    """Delete (soft delete) computer."""
    comp = db.session.get(Computer, computer_id)

    if not comp:
        return error_response(
            ErrorCodes.NOT_FOUND,
            f'Computer with ID {computer_id} not found',
            http_code=404
        )

    # Soft delete the asset
    comp.asset.isactive = False

    # Audit log
    AuditLog.log('deleted', 'Computer', entityid=comp.computerid,
                 entityname=comp.hostname or comp.asset.assetnumber)

    db.session.commit()

    return success_response(message='Computer deleted')


# =============================================================================
# Installed Applications
# =============================================================================

@computers_bp.route('/<int:computer_id>/apps', methods=['GET'])
@jwt_required(optional=True)
def get_installed_apps(computer_id: int):
    """Get all installed applications for a computer."""
    comp = db.session.get(Computer, computer_id)

    if not comp:
        return error_response(
            ErrorCodes.NOT_FOUND,
            f'Computer with ID {computer_id} not found',
            http_code=404
        )

    apps = ComputerInstalledApp.query.filter_by(
        computerid=computer_id,
        isactive=True
    ).all()

    data = [app.to_dict() for app in apps]

    return success_response(data)


@computers_bp.route('/<int:computer_id>/apps', methods=['POST'])
@jwt_required()
@require_permission('computers.create')
def add_installed_app(computer_id: int):
    """Add an installed application to a computer."""
    comp = db.session.get(Computer, computer_id)

    if not comp:
        return error_response(
            ErrorCodes.NOT_FOUND,
            f'Computer with ID {computer_id} not found',
            http_code=404
        )

    data = request.get_json()
    if not data or not data.get('appid'):
        return error_response(ErrorCodes.VALIDATION_ERROR, 'appid is required')

    appid = data['appid']

    # Validate app exists
    if not db.session.get(Application, appid):
        return error_response(ErrorCodes.NOT_FOUND, f'Application {appid} not found', http_code=404)

    # Check for duplicate
    existing = ComputerInstalledApp.query.filter_by(
        computerid=computer_id,
        appid=appid
    ).first()

    if existing:
        if existing.isactive:
            return error_response(
                ErrorCodes.CONFLICT,
                'This application is already installed on this computer',
                http_code=409
            )
        else:
            # Reactivate
            existing.isactive = True
            existing.appversionid = data.get('appversionid')
            db.session.commit()
            return success_response(existing.to_dict(), message='Application reinstalled')

    # Create new installation record
    installed = ComputerInstalledApp(
        computerid=computer_id,
        appid=appid,
        appversionid=data.get('appversionid')
    )

    db.session.add(installed)
    db.session.commit()

    return success_response(installed.to_dict(), message='Application installed', http_code=201)


@computers_bp.route('/<int:computer_id>/apps/<int:app_id>', methods=['DELETE'])
@jwt_required()
@require_permission('computers.delete')
def remove_installed_app(computer_id: int, app_id: int):
    """Remove an installed application from a computer."""
    installed = ComputerInstalledApp.query.filter_by(
        computerid=computer_id,
        appid=app_id,
        isactive=True
    ).first()

    if not installed:
        return error_response(
            ErrorCodes.NOT_FOUND,
            'Installation record not found',
            http_code=404
        )

    installed.isactive = False
    db.session.commit()

    return success_response(message='Application uninstalled')


# =============================================================================
# Status Reporting
# =============================================================================

@computers_bp.route('/<int:computer_id>/report', methods=['POST'])
@jwt_required()
@require_permission('computers.create')
def report_status(computer_id: int):
    """
    Report computer status (for agent-based reporting).

    This endpoint can be called periodically by a client agent
    to update status information.
    """
    comp = db.session.get(Computer, computer_id)

    if not comp:
        return error_response(
            ErrorCodes.NOT_FOUND,
            f'Computer with ID {computer_id} not found',
            http_code=404
        )

    data = request.get_json() or {}

    # Update status fields
    from datetime import datetime, timezone
    comp.lastreporteddate = datetime.now(timezone.utc).replace(tzinfo=None)

    if 'loggedinuser' in data:
        comp.loggedinuser = data['loggedinuser']
    if 'lastboottime' in data:
        comp.lastboottime = data['lastboottime']

    db.session.commit()

    return success_response(message='Status reported')


# =============================================================================
# Dashboard
# =============================================================================

@computers_bp.route('/dashboard/summary', methods=['GET'])
@jwt_required(optional=True)
def dashboard_summary():
    """Get computer dashboard summary data."""
    # Total active computers
    total = db.session.query(Computer).join(Asset).filter(
        Asset.isactive == True
    ).count()

    # Count by computer type
    by_type = db.session.query(
        ComputerType.computertype,
        db.func.count(Computer.computerid)
    ).join(Computer, Computer.computertypeid == ComputerType.computertypeid
    ).join(Asset, Asset.assetid == Computer.assetid
    ).filter(Asset.isactive == True
    ).group_by(ComputerType.computertype
    ).all()

    # Count by OS
    by_os = db.session.query(
        OperatingSystem.osname,
        db.func.count(Computer.computerid)
    ).join(Computer, Computer.osid == OperatingSystem.osid
    ).join(Asset, Asset.assetid == Computer.assetid
    ).filter(Asset.isactive == True
    ).group_by(OperatingSystem.osname
    ).all()

    # Count shopfloor vs non-shopfloor
    sf = ComputerType.query.filter_by(computertype='Shopfloor').first()
    shopfloor_count = db.session.query(Computer).join(Asset).filter(
        Asset.isactive == True,
        Computer.computertypeid == (sf.computertypeid if sf else -1)
    ).count()

    return success_response({
        'total': total,
        'bytype': [{'type': t, 'count': c} for t, c in by_type],
        'byos': [{'os': o, 'count': c} for o, c in by_os],
        'shopfloor': shopfloor_count,
        'nonshopfloor': total - shopfloor_count
    })


@computers_bp.route('/dashboard/quiet', methods=['GET'])
@jwt_required()
@require_permission('computers.view')
def dashboard_quiet():
    """PCs that WERE reporting, have stopped, and are still meant to be in use.

    Three filters, and each removes a population that would otherwise be noise:

    Never reported at all is EXCLUDED. Those are usually records created by
    hand or imported, not bays that broke - listing them buries the PCs that
    actually changed state behind rows nobody is going to act on.

    Not In Use is EXCLUDED. A PC in Repair, Inventory or Retired is silent on
    purpose; that is the status doing its job, not a fault.

    Soft-deleted is excluded for the same reason.

    What is left is the real signal: a machine that was working, is not now, and
    nobody has marked as anything else. Silence is the only evidence available -
    there is no heartbeat separate from the report.
    """
    from datetime import datetime, timedelta, timezone
    from shopdb.api import AssetStatus

    hours = 24
    setting = Setting.query.filter_by(key='computers_quietreporthours').first()
    if setting and (setting.value or '').strip():
        try:
            hours = int(setting.value)
        except (TypeError, ValueError):
            pass
    cutoff = datetime.now(timezone.utc).replace(tzinfo=None) - timedelta(hours=hours)
    now = datetime.now(timezone.utc).replace(tzinfo=None)

    rows = (db.session.query(Computer, Asset)
            .join(Asset, Asset.assetid == Computer.assetid)
            .join(AssetStatus, AssetStatus.statusid == Asset.statusid)
            .filter(Asset.isactive.is_(True),
                    AssetStatus.status == 'In Use',
                    Computer.lastreporteddate.isnot(None),
                    Computer.lastreporteddate < cutoff)
            .all())

    out = [{
        'computerid': comp.computerid,
        'hostname': comp.hostname,
        'lastreported': comp.lastreporteddate.isoformat() + 'Z',
        'quietdays': (now - comp.lastreporteddate).days,
    } for comp, _asset in rows]

    out.sort(key=lambda r: -r['quietdays'])
    return success_response(out[:50])


@computers_bp.route('/dashboard/sharedmachines', methods=['GET'])
@jwt_required()
@require_permission('computers.view')
def dashboard_sharedmachines():
    """Machine numbers claimed by more than one PC, with nothing filed under
    them.

    Several devices genuinely sharing a number is legitimate - part markers do
    it - and those are modelled: each device is its own asset filed `partof` the
    operation, so the operation has CHILD ASSETS. Two PCs carrying the same
    machine number by mistake looks identical from a count and has none. That
    distinction is the whole card; without it this would list correct data
    alongside faults and get ignored.

    Promoted from `flask relationships check-shared-machines`, which answers the
    same question and which nobody will remember to run. This one found seven
    mis-numbered bays that had been that way for weeks.
    """
    from shopdb.api import AssetRelationship, RelationshipType
    from sqlalchemy.orm import aliased

    controls = RelationshipType.query.filter_by(
        relationshiptype='controls').first()
    partof = RelationshipType.query.filter_by(relationshiptype='partof').first()
    if not controls:
        return success_response([])

    pcasset = aliased(Asset)
    machineasset = aliased(Asset)

    rows = (db.session.query(machineasset.assetid, machineasset.assetnumber,
                             pcasset.assetnumber)
            .select_from(AssetRelationship)
            .join(pcasset, AssetRelationship.sourceassetid == pcasset.assetid)
            .join(machineasset,
                  AssetRelationship.targetassetid == machineasset.assetid)
            .filter(AssetRelationship.relationshiptypeid ==
                    controls.relationshiptypeid,
                    AssetRelationship.label == 'collector:machine',
                    AssetRelationship.isactive.is_(True))
            .all())

    bymachine = {}
    for assetid, machinenumber, pcnumber in rows:
        bymachine.setdefault((assetid, machinenumber), []).append(pcnumber)

    out = []
    for (assetid, machinenumber), pcs in bymachine.items():
        if len(pcs) < 2:
            continue
        children = 0
        if partof:
            children = (AssetRelationship.query
                        .filter_by(targetassetid=assetid,
                                   relationshiptypeid=partof.relationshiptypeid,
                                   isactive=True)
                        .count())
        if children:
            continue   # modelled: the devices are assets in their own right
        out.append({
            'assetid': assetid,
            'machinenumber': machinenumber,
            'pccount': len(pcs),
            'pcs': ', '.join(sorted(p for p in pcs if p)),
        })

    out.sort(key=lambda r: -r['pccount'])
    return success_response(out)