"""Employee lookup API endpoints.

These read from the separate employee directory DB (employee_connection is core
infrastructure exposed via shopdb.api, shared with search + notifications). The
endpoints are intentionally reachable by the unauthenticated shopfloor kiosk
displays (recognition wall), so they are not JWT-gated; keep them read-only and
never return more than the directory fields below.
"""

import csv
import glob
import io
import logging
import os

from flask import Blueprint, request, current_app, send_from_directory
from flask_jwt_extended import jwt_required
from werkzeug.utils import secure_filename

from shopdb.api import (
    db,
    success_response,
    error_response,
    ErrorCodes,
    employee_connection,
    require_role,
)
from shopdb.api import Setting

from ..models import DirectoryEmployee

logger = logging.getLogger(__name__)

employees_bp = Blueprint('employees', __name__)

# Columns safe to expose to the directory/recognition UI
_FIELDS = 'SSO, First_Name, Last_Name, Team, Role, Picture'

# Uploaded self-hosted employee photos live in the instance dir and are served
# publicly (kiosk recognition/recertification cards read them without auth).
EMPLOYEE_PHOTO_EXTENSIONS = {'.png', '.jpg', '.jpeg', '.gif', '.webp'}

# URL prefix a served upload resolves to (self-hosted mode).
EMPLOYEE_PHOTO_URL_PREFIX = '/api/employees/photo/'

# Fallback URL prefix external HR relative picture paths resolve under when
# the employee_photo_base_url setting is unset. Sites whose photos live on
# another host (e.g. the classic EmployeeDBAPP) set the setting to a full URL
# such as https://host/EmployeeDBAPP/images/ instead.
EMPLOYEE_PHOTO_STATIC_PREFIX = '/static/employees/'


def _employeephoto_dir():
    return os.path.join(current_app.instance_path, 'employeephotos')


def _selfhosted():
    """True when the directory is the app-owned table, not an external HR DB."""
    row = Setting.query.filter_by(key='employee_directory_mode').first()
    return (row.value if row and row.value else 'external').lower() == 'selfhosted'


def _require_selfhosted():
    """Guard for management endpoints - only valid in self-hosted mode."""
    if not _selfhosted():
        return error_response(
            ErrorCodes.VALIDATION_ERROR,
            'Directory is in external mode; manage people in the source HR database.',
            http_code=400)
    return None


def _require_selfhosted_photo():
    """Guard for photo write endpoints - 409 when the directory is external.

    In external mode the photo is owned by the HR database (read-only
    pass-through), so upload/delete cannot apply here."""
    if not _selfhosted():
        return error_response(
            ErrorCodes.CONFLICT,
            'Employee directory is external; photos are supplied by the HR '
            'database and cannot be uploaded or deleted here.',
            http_code=409)
    return None


def _external_photo_url(picture):
    """Turn an external HR Picture value into a usable URL, or None.

    Absolute URLs and already-rooted paths pass through untouched (future
    full-URL HR feeds); a bare relative path is served under the static prefix
    (current WJ convention, e.g. 'Support/210009518.png')."""
    if not picture:
        return None
    text = str(picture).strip()
    if not text:
        return None
    if text.startswith(('http://', 'https://', '/')):
        return text
    from shopdb.api import Setting
    base = (Setting.get('employee_photo_base_url') or '').strip() \
        or EMPLOYEE_PHOTO_STATIC_PREFIX
    return base.rstrip('/') + '/' + text.lstrip('/')


def _hr_picture(sso):
    """Raw Picture value for an SSO from the external HR directory. None on miss."""
    try:
        conn = employee_connection()
        with conn.cursor() as cur:
            cur.execute('SELECT Picture FROM employees WHERE SSO = %s', (int(sso),))
            row = cur.fetchone()
        conn.close()
        return row.get('Picture') if row else None
    except Exception:
        return None


def resolve_employee_photo_url(sso, external_picture=None):
    """Single resolver both consumers share: the display photo URL for an SSO.

    Self-hosted: the served upload URL when the employee has an uploaded photo,
    else None (the legacy Picture text field does not drive the photo here).
    External: the HR-supplied Picture resolved to a URL (pass external_picture to
    avoid a re-query), else None. Returns None on any miss or bad SSO."""
    if sso is None or not str(sso).isdigit():
        return None
    if _selfhosted():
        emp = db.session.get(DirectoryEmployee, int(sso))
        if emp and emp.photofilename:
            return EMPLOYEE_PHOTO_URL_PREFIX + emp.photofilename
        return None
    picture = external_picture if external_picture is not None else _hr_picture(sso)
    return _external_photo_url(picture)


def _with_photo_url(employee):
    """Add the resolved photourl to an employee dict (self-hosted or external)."""
    employee['photourl'] = resolve_employee_photo_url(
        employee.get('SSO'), employee.get('Picture'))
    return employee


@employees_bp.route('/search', methods=['GET'])
def search_employees():
    """
    Search employees by name.

    Query parameters:
    - q: Search query (searches first and last name)
    - limit: Max results (default 10)
    """
    query = request.args.get('q', '').strip()
    limit = min(int(request.args.get('limit', 10)), 50)

    if len(query) < 2:
        return error_response(
            ErrorCodes.VALIDATION_ERROR,
            'Search query must be at least 2 characters'
        )

    if _selfhosted():
        term = f'%{query}%'
        rows = (DirectoryEmployee.query
                .filter(db.or_(DirectoryEmployee.firstname.ilike(term),
                               DirectoryEmployee.lastname.ilike(term),
                               db.cast(DirectoryEmployee.sso, db.String).ilike(term)))
                .order_by(DirectoryEmployee.lastname, DirectoryEmployee.firstname)
                .limit(limit).all())
        return success_response([_with_photo_url(e.to_dict()) for e in rows])

    try:
        conn = employee_connection()
        with conn.cursor() as cur:
            cur.execute(f'''
                SELECT {_FIELDS}
                FROM employees
                WHERE First_Name LIKE %s
                   OR Last_Name LIKE %s
                   OR CAST(SSO AS CHAR) LIKE %s
                ORDER BY Last_Name, First_Name
                LIMIT %s
            ''', (f'%{query}%', f'%{query}%', f'%{query}%', limit))
            employees = cur.fetchall()
        conn.close()
        return success_response([_with_photo_url(e) for e in employees])
    except Exception:
        logger.exception('Employee search failed')
        return error_response(
            ErrorCodes.INTERNAL_ERROR,
            'Employee lookup failed',
            http_code=500
        )


@employees_bp.route('/lookup/<sso>', methods=['GET'])
def lookup_employee(sso):
    """Look up a single employee by SSO."""
    if not sso.isdigit():
        return error_response(
            ErrorCodes.VALIDATION_ERROR,
            'SSO must be numeric'
        )

    if _selfhosted():
        emp = db.session.get(DirectoryEmployee, int(sso))
        if not emp:
            return error_response(ErrorCodes.NOT_FOUND,
                                  f'Employee with SSO {sso} not found', http_code=404)
        return success_response(_with_photo_url(emp.to_dict()))

    try:
        conn = employee_connection()
        with conn.cursor() as cur:
            cur.execute(
                f'SELECT {_FIELDS} FROM employees WHERE SSO = %s',
                (int(sso),)
            )
            employee = cur.fetchone()
        conn.close()

        if not employee:
            return error_response(
                ErrorCodes.NOT_FOUND,
                f'Employee with SSO {sso} not found',
                http_code=404
            )

        return success_response(_with_photo_url(employee))
    except Exception:
        logger.exception('Employee lookup failed for SSO %s', sso)
        return error_response(
            ErrorCodes.INTERNAL_ERROR,
            'Employee lookup failed',
            http_code=500
        )


@employees_bp.route('/lookup', methods=['GET'])
def lookup_employees():
    """
    Look up multiple employees by SSO list.

    Query parameters:
    - sso: Comma-separated list of SSOs
    """
    sso_list = request.args.get('sso', '')
    ssos = [s.strip() for s in sso_list.split(',') if s.strip().isdigit()]

    if not ssos:
        return error_response(
            ErrorCodes.VALIDATION_ERROR,
            'At least one valid SSO is required'
        )

    if _selfhosted():
        rows = DirectoryEmployee.query.filter(
            DirectoryEmployee.sso.in_([int(s) for s in ssos])).all()
        employees = [_with_photo_url(e.to_dict()) for e in rows]
        names = ', '.join(f"{e['First_Name'].strip()} {e['Last_Name'].strip()}"
                          for e in employees)
        return success_response({'employees': employees, 'names': names})

    try:
        conn = employee_connection()
        with conn.cursor() as cur:
            placeholders = ','.join(['%s'] * len(ssos))
            cur.execute(
                f'SELECT {_FIELDS} FROM employees WHERE SSO IN ({placeholders})',
                [int(s) for s in ssos]
            )
            employees = cur.fetchall()
        conn.close()

        employees = [_with_photo_url(e) for e in employees]
        names = ', '.join(
            f"{e['First_Name'].strip()} {e['Last_Name'].strip()}"
            for e in employees
        )

        return success_response({
            'employees': employees,
            'names': names
        })
    except Exception:
        logger.exception('Employee multi-lookup failed')
        return error_response(
            ErrorCodes.INTERNAL_ERROR,
            'Employee lookup failed',
            http_code=500
        )


# =============================================================================
# Self-hosted directory management (only when directory_mode=selfhosted)
# =============================================================================

@employees_bp.route('/directory', methods=['GET'])
@jwt_required(optional=True)
def list_directory():
    """Full self-hosted directory (for the management page)."""
    guard = _require_selfhosted()
    if guard:
        return guard
    rows = (DirectoryEmployee.query
            .order_by(DirectoryEmployee.lastname, DirectoryEmployee.firstname).all())
    return success_response([_with_photo_url(e.to_dict()) for e in rows])


def _employee_from_payload(data):
    """Build kwargs from a payload accepting either external-style (SSO,
    First_Name...) or plain (sso, firstname...) keys."""
    def pick(*keys):
        for key in keys:
            if data.get(key) not in (None, ''):
                return data.get(key)
        return None
    return {
        'sso': pick('sso', 'SSO'),
        'firstname': pick('firstname', 'First_Name'),
        'lastname': pick('lastname', 'Last_Name'),
        'team': pick('team', 'Team'),
        'role': pick('role', 'Role'),
        'picture': pick('picture', 'Picture'),
    }


@employees_bp.route('/directory', methods=['POST'])
@jwt_required()
@require_role('admin')
def create_directory_employee():
    guard = _require_selfhosted()
    if guard:
        return guard
    fields = _employee_from_payload(request.get_json() or {})
    if not (fields['sso'] and fields['firstname'] and fields['lastname']):
        return error_response(ErrorCodes.VALIDATION_ERROR, 'sso, firstname and lastname are required')
    try:
        sso = int(fields['sso'])
    except (ValueError, TypeError):
        return error_response(ErrorCodes.VALIDATION_ERROR, 'sso must be numeric')
    if db.session.get(DirectoryEmployee, sso):
        return error_response(ErrorCodes.CONFLICT, f'SSO {sso} already exists', http_code=409)
    emp = DirectoryEmployee(sso=sso, firstname=fields['firstname'], lastname=fields['lastname'],
                            team=fields['team'], role=fields['role'], picture=fields['picture'])
    db.session.add(emp)
    db.session.commit()
    return success_response(emp.to_dict(), message='Employee added', http_code=201)


@employees_bp.route('/directory/<int:sso>', methods=['PUT'])
@jwt_required()
@require_role('admin')
def update_directory_employee(sso):
    guard = _require_selfhosted()
    if guard:
        return guard
    emp = db.session.get(DirectoryEmployee, sso)
    if not emp:
        return error_response(ErrorCodes.NOT_FOUND, 'Employee not found', http_code=404)
    fields = _employee_from_payload(request.get_json() or {})
    if fields['firstname']:
        emp.firstname = fields['firstname']
    if fields['lastname']:
        emp.lastname = fields['lastname']
    for key in ('team', 'role', 'picture'):
        if key in (request.get_json() or {}) or fields[key] is not None:
            setattr(emp, key, fields[key])
    db.session.commit()
    return success_response(emp.to_dict(), message='Employee updated')


@employees_bp.route('/directory/<int:sso>', methods=['DELETE'])
@jwt_required()
@require_role('admin')
def delete_directory_employee(sso):
    guard = _require_selfhosted()
    if guard:
        return guard
    emp = db.session.get(DirectoryEmployee, sso)
    if not emp:
        return error_response(ErrorCodes.NOT_FOUND, 'Employee not found', http_code=404)
    db.session.delete(emp)
    db.session.commit()
    return success_response(message='Employee removed')


@employees_bp.route('/directory/import', methods=['POST'])
@jwt_required()
@require_role('admin')
def import_directory():
    """Bulk upsert from CSV. Accepts headers SSO,First_Name,Last_Name,Team,Role,
    Picture (case-insensitive; sso/firstname/... also accepted)."""
    guard = _require_selfhosted()
    if guard:
        return guard
    text = ''
    if 'file' in request.files:
        text = request.files['file'].read().decode('utf-8-sig', errors='replace')
    else:
        data = request.get_json(silent=True) or {}
        text = data.get('csv', '')
    if not text.strip():
        return error_response(ErrorCodes.VALIDATION_ERROR, 'No CSV provided')

    reader = csv.DictReader(io.StringIO(text))
    # Normalize headers to lower for tolerant matching.
    added = updated = skipped = 0
    for raw in reader:
        row = {(k or '').strip().lower(): (v or '').strip() for k, v in raw.items()}
        sso_raw = row.get('sso') or row.get('sso ')
        first = row.get('first_name') or row.get('firstname')
        last = row.get('last_name') or row.get('lastname')
        if not (sso_raw and sso_raw.isdigit() and first and last):
            skipped += 1
            continue
        sso = int(sso_raw)
        team = row.get('team') or None
        role = row.get('role') or None
        picture = row.get('picture') or None
        emp = db.session.get(DirectoryEmployee, sso)
        if emp:
            emp.firstname, emp.lastname, emp.team, emp.role, emp.picture = first, last, team, role, picture
            updated += 1
        else:
            db.session.add(DirectoryEmployee(sso=sso, firstname=first, lastname=last,
                                             team=team, role=role, picture=picture))
            added += 1
    db.session.commit()
    return success_response({'added': added, 'updated': updated, 'skipped': skipped},
                            message=f'Import done: {added} added, {updated} updated, {skipped} skipped.')


# =============================================================================
# Self-hosted employee photos (upload/replace/delete + public serve)
# =============================================================================

@employees_bp.route('/<int:sso>/photo', methods=['POST'])
@jwt_required()
@require_role('admin')
def upload_employee_photo(sso):
    """Upload (or replace) the photo for a self-hosted directory employee.

    multipart/form-data: file=<image>. Saves to the instance employeephotos dir
    as photo-<sso><ext> (one photo per person) and points photofilename at it.
    Re-upload replaces the old file even when the extension changes. External
    mode is a 409 (photo is owned by the HR database)."""
    guard = _require_selfhosted_photo()
    if guard:
        return guard

    emp = db.session.get(DirectoryEmployee, sso)
    if not emp:
        return error_response(ErrorCodes.NOT_FOUND, 'Employee not found', http_code=404)

    upload = request.files.get('file')
    if not upload or not upload.filename:
        return error_response(ErrorCodes.VALIDATION_ERROR, 'No file provided')
    ext = os.path.splitext(upload.filename)[1].lower()
    if ext not in EMPLOYEE_PHOTO_EXTENSIONS:
        return error_response(ErrorCodes.VALIDATION_ERROR,
                              f'Unsupported image type {ext}')

    photodir = _employeephoto_dir()
    os.makedirs(photodir, exist_ok=True)

    # Wipe any prior photo-<sso>.* so a new extension does not orphan the old one.
    for old in glob.glob(os.path.join(photodir, secure_filename(f'photo-{sso}') + '.*')):
        os.remove(old)

    filename = secure_filename(f'photo-{sso}{ext}')
    upload.save(os.path.join(photodir, filename))

    emp.photofilename = filename
    db.session.commit()

    return success_response(_with_photo_url(emp.to_dict()), message='Employee photo uploaded')


@employees_bp.route('/photo/<path:filename>', methods=['GET'])
def serve_employee_photo(filename):
    """Serve an uploaded employee photo (public - kiosk cards read it)."""
    return send_from_directory(_employeephoto_dir(), filename)


@employees_bp.route('/<int:sso>/photo', methods=['DELETE'])
@jwt_required()
@require_role('admin')
def delete_employee_photo(sso):
    """Clear an employee photo and delete the uploaded file. External mode 409s."""
    guard = _require_selfhosted_photo()
    if guard:
        return guard

    emp = db.session.get(DirectoryEmployee, sso)
    if not emp:
        return error_response(ErrorCodes.NOT_FOUND, 'Employee not found', http_code=404)

    if emp.photofilename:
        # secure_filename strips any traversal; the file lives in our dir only.
        path = os.path.join(_employeephoto_dir(), secure_filename(emp.photofilename))
        if os.path.exists(path):
            os.remove(path)

    emp.photofilename = None
    db.session.commit()

    return success_response(_with_photo_url(emp.to_dict()), message='Employee photo removed')