"""Бизнес-логика AMI: канал по типу линии, originate, ping."""
from __future__ import annotations

import re
from typing import TYPE_CHECKING

from core.models import ConnectorConfig

from .ami import AmiClient, AmiError, DEFAULT_PORT

if TYPE_CHECKING:
    from apps.employees.models import Employee

EXTEN_RE = re.compile(r'^\d{2,10}$')
CONNECTOR = 'asterisk'

DEFAULT_SIP_CHANNEL = 'PJSIP/{exten}'
DEFAULT_ANALOG_CHANNEL = 'DAHDI/{exten}'
DEFAULT_CONTEXT = 'from-internal'


class TelephonyError(Exception):
    """Ошибка звонка с понятным текстом для пользователя."""


def get_ami_config() -> ConnectorConfig | None:
    return ConnectorConfig.get_for(CONNECTOR)


def ami_is_enabled() -> bool:
    return get_ami_config() is not None


def sanitize_exten(raw: str) -> str:
    digits = re.sub(r'\D', '', raw or '')
    if not EXTEN_RE.fullmatch(digits):
        raise TelephonyError('Некорректный внутренний номер.')
    return digits


def channel_for_employee(employee, extra: dict | None = None) -> str:
    extra = extra or {}
    exten = sanitize_exten(employee.internal_number)
    line = getattr(employee, 'internal_line_type', '') or 'analog'
    if line == 'sip':
        template = (extra.get('sip_channel') or DEFAULT_SIP_CHANNEL)
    else:
        template = (extra.get('analog_channel') or DEFAULT_ANALOG_CHANNEL)
    return str(template).replace('{exten}', exten)


def _client_from_config(cfg: ConnectorConfig) -> AmiClient:
    extra = cfg.extra_config or {}
    timeout = extra.get('timeout', 8)
    try:
        timeout = float(timeout)
    except (TypeError, ValueError):
        timeout = 8
    return AmiClient(
        host=cfg.host,
        port=cfg.port or DEFAULT_PORT,
        username=cfg.username,
        secret=cfg.password,
        timeout=timeout,
        use_ssl=bool(cfg.use_ssl),
    )


def ping_ami(cfg: ConnectorConfig | None = None) -> dict:
    cfg = cfg or get_ami_config()
    if cfg is None:
        raise TelephonyError('Коннектор Asterisk AMI выключен.')
    if not cfg.host or not cfg.username or not cfg.password:
        raise TelephonyError('В AMI не заданы хост, логин или секрет.')
    with _client_from_config(cfg) as client:
        return client.ping()


def originate_between(caller: Employee, callee: Employee) -> dict:
    if caller.pk == callee.pk:
        raise TelephonyError('Нельзя позвонить самому себе.')
    if not caller.internal_number:
        raise TelephonyError('У вас не указан внутренний номер.')
    if not callee.internal_number:
        raise TelephonyError('У сотрудника нет внутреннего номера.')

    cfg = get_ami_config()
    if cfg is None:
        raise TelephonyError('Коннектор Asterisk AMI выключен.')

    extra = cfg.extra_config or {}
    context = extra.get('originate_context') or DEFAULT_CONTEXT
    channel = channel_for_employee(caller, extra)
    dest = sanitize_exten(callee.internal_number)
    caller_id = f'{caller.short_name} <{sanitize_exten(caller.internal_number)}>'

    try:
        with _client_from_config(cfg) as client:
            return client.originate(
                channel=channel,
                exten=dest,
                context=context,
                caller_id=caller_id,
            )
    except AmiError as exc:
        raise TelephonyError(str(exc)) from exc