import os
from django.contrib.auth.decorators import login_required
from django.contrib.auth.forms import PasswordChangeForm
from django.utils.dateparse import parse_date
from datetime import datetime, time, timedelta
import base64
import re
import urllib.parse
import urllib.request
import csv
import io
import json
from django.http import JsonResponse, HttpResponse
from django.urls import reverse
from django.shortcuts import render, redirect, get_object_or_404
from django.db import transaction
from django.db.models import Q, Sum, Value, DecimalField
from django.contrib import messages
from django.core.paginator import Paginator
from django.conf import settings
from django.db.models.functions import Coalesce
from .models import format_phone_number, Voter, Tenant, Interaction, Donation, VoterLikelihood, EventParticipation, Event, EventType, InteractionType, DonationMethod, ElectionType, CampaignSettings, Volunteer, ParticipationStatus, VolunteerEvent, Interest, VolunteerRole, ScheduledCall, BulkTask
from .filter_helper import get_filtered_voter_queryset, get_phone_search_filters
from .forms import VoterForm, InteractionForm, DonationForm, VoterLikelihoodForm, EventParticipationForm, VoterImportForm, AdvancedVoterSearchForm, EventParticipantAddForm, EventForm, VolunteerForm, VolunteerEventForm, VolunteerEventAddForm, DoorVisitLogForm, ScheduledCallForm, UserUpdateForm, EventParticipationImportForm, ParticipantMappingForm
from django.core.mail import get_connection, EmailMessage
import logging
import zoneinfo
from django.utils import timezone

from .permissions import role_required, can_view_donations, can_edit_voter, can_view_volunteers, can_edit_volunteer, can_view_voters, get_user_role, STAFF_ROLES, can_access_call_queue
logger = logging.getLogger(__name__)

from .task_runners import start_bulk_sms_task

def _robust_decode(content):
    if not content:
        return ""
    for enc in ["utf-8-sig", "utf-8", "iso-8859-1", "windows-1252"]:
        try:
            return content.decode(enc)
        except UnicodeDecodeError:
            continue
    return content.decode("utf-8", errors="replace")


def _handle_uploaded_file(uploaded_file):
    """
    Handles uploaded CSV files, saves them to a temporary file, and extracts headers.
    Returns (headers, temp_file_path) or (None, None) if an error occurs.
    """
    import tempfile
    try:
        with tempfile.NamedTemporaryFile(delete=False, suffix=".csv") as tmp:
            for chunk in uploaded_file.chunks():
                tmp.write(chunk)
            return tmp.name
    except Exception as e:
        logger.error(f"Error handling uploaded file: {e}")
        return None