import re

from django.db.models import Case, IntegerField, Q, Value, When
from django.http import JsonResponse
from django.views.decorators.http import require_GET

from apps.customers.models import CustomerProfile

from .models import PhoneContactApiKey


_PHONE_DIGITS = str.maketrans("۰۱۲۳۴۵۶۷۸۹٠١٢٣٤٥٦٧٨٩", "01234567890123456789")


def _dialable_number(value):
    number = re.sub(r"[\s().-]", "", str(value or "").translate(_PHONE_DIGITS))
    return number if 0 < len(number) <= 64 and re.fullmatch(r"[0-9+*#]+", number) else ""


def _canonical_number(value):
    number = _dialable_number(value)
    if not number or not re.fullmatch(r"\+[0-9]+|[0-9*#]+", number):
        return ""
    if number.isdigit() and number.startswith("00") and len(number) > 2:
        return "+" + number[2:]
    if number.isdigit() and number.startswith("98") and len(number) >= 12:
        return "+" + number
    if number.isdigit() and number.startswith("0") and len(number) > 1:
        return "+98" + number[1:]
    if number.isdigit() and len(number) == 10:
        return "+98" + number
    return number


def _phone_variants(value):
    canonical = _canonical_number(value)
    if not canonical:
        return ()
    variants = {canonical, _dialable_number(value)}
    if canonical.startswith("+98"):
        variants.update({"0" + canonical[3:], "00" + canonical[1:], canonical[1:]})
    elif canonical.startswith("+"):
        variants.add("00" + canonical[1:])
    return variants


def _display_number(value):
    canonical = _canonical_number(value)
    return "0" + canonical[3:] if canonical.startswith("+98") else canonical


def _json(data, status=200):
    response = JsonResponse(data, status=status, json_dumps_params={"ensure_ascii": False})
    response["Cache-Control"] = "no-store"
    return response


def _matching_contacts(contacts, query):
    phone_query = query.translate(_PHONE_DIGITS)
    if re.fullmatch(r"[+*#0-9().\s-]+", phone_query):
        variants = _phone_variants(phone_query)
        return contacts.filter(user__mobile__in=variants).order_by("pk") if variants else contacts.none()

    for word in re.split(r"\s+", query):
        contacts = contacts.filter(
            Q(first_name__icontains=word) | Q(last_name__icontains=word) |
            Q(organization_name__icontains=word) | Q(user__first_name__icontains=word) |
            Q(user__last_name__icontains=word) | Q(user__mobile__icontains=word)
        )

    preferred = (
        Q(first_name__iexact=query) | Q(last_name__iexact=query) |
        Q(organization_name__iexact=query) | Q(user__first_name__iexact=query) |
        Q(user__last_name__iexact=query)
    )
    starts_with = (
        Q(first_name__istartswith=query) | Q(last_name__istartswith=query) |
        Q(organization_name__istartswith=query) | Q(user__first_name__istartswith=query) |
        Q(user__last_name__istartswith=query)
    )
    return contacts.annotate(_search_rank=Case(
        When(preferred, then=Value(0)),
        When(starts_with, then=Value(1)),
        default=Value(2), output_field=IntegerField(),
    )).order_by("_search_rank", "pk")


@require_GET
def phone_contacts(request):
    authorization = request.headers.get("Authorization", "")
    scheme, separator, token = authorization.partition(" ")
    if not separator or scheme.lower() != "bearer" or not token or token != token.strip():
        return _json({"error": "unauthorized"}, 401)

    credential = PhoneContactApiKey.objects.filter(pk=1, is_active=True).first()
    if not credential or not credential.accepts(token):
        return _json({"error": "unauthorized"}, 401)

    query = request.GET.get("search", "").strip()[:80]
    if len(query) < 2:
        return _json({"contacts": []})

    try:
        limit = min(50, max(1, int(request.GET.get("limit", "50"))))
    except ValueError:
        return _json({"error": "invalid limit"}, 400)

    query = query.translate(str.maketrans({"ي": "ی", "ك": "ک", "۰": "0", "۱": "1", "۲": "2", "۳": "3", "۴": "4", "۵": "5", "۶": "6", "۷": "7", "۸": "8", "۹": "9"}))
    contacts = CustomerProfile.objects.select_related("user").filter(
        user__account_type="CUSTOMER", user__is_active=True, user__mobile__isnull=False
    ).exclude(user__mobile="").filter(
        Q(first_name__gt="") | Q(last_name__gt="") | Q(organization_name__gt="") |
        Q(user__first_name__gt="") | Q(user__last_name__gt="")
    )
    results = []
    for profile in _matching_contacts(contacts, query)[:limit]:
        name = (f"{profile.first_name} {profile.last_name}".strip() or
                f"{profile.user.first_name} {profile.user.last_name}".strip() or
                profile.organization_name.strip())[:120]
        number = _display_number(profile.user.mobile)
        if name and number:
            label = "همراه" if re.fullmatch(r"09[0-9]{9}", number) else "تلفن"
            results.append({"name": name, "mobile": number, "phones": [{"type": label, "number": number}]})
    return _json({"contacts": results})