"""Utility functions for the MQTT integration."""

from __future__ import annotations

import asyncio
from collections.abc import Callable, Coroutine
from functools import lru_cache
import logging
import os
from pathlib import Path
import tempfile
from typing import Any

import voluptuous as vol

from homeassistant.config_entries import ConfigEntry, ConfigEntryState
from homeassistant.const import MAX_LENGTH_STATE_STATE, STATE_UNKNOWN, Platform
from homeassistant.core import HomeAssistant, callback
from homeassistant.exceptions import HomeAssistantError
from homeassistant.helpers import config_validation as cv, template
from homeassistant.helpers.typing import ConfigType
from homeassistant.util.async_ import create_eager_task

from .const import (
    ATTR_PAYLOAD,
    ATTR_QOS,
    ATTR_RETAIN,
    ATTR_TOPIC,
    CONF_CERTIFICATE,
    CONF_CLIENT_CERT,
    CONF_CLIENT_KEY,
    DEFAULT_ENCODING,
    DEFAULT_QOS,
    DEFAULT_RETAIN,
    DOMAIN,
)
from .models import DATA_MQTT, DATA_MQTT_AVAILABLE, ReceiveMessage

AVAILABILITY_TIMEOUT = 50.0

TEMP_DIR_NAME = f"home-assistant-{DOMAIN}"

_VALID_QOS_SCHEMA = vol.All(vol.Coerce(int), vol.In([0, 1, 2]))

_LOGGER = logging.getLogger(__name__)


class EnsureJobAfterCooldown:
    """Ensure a cool down period before executing a job.

    When a new execute request arrives we cancel the current request
    and start a new one.

    We allow patching this util, as we generally have exceptions
    for sleeps/waits/debouncers/timers causing long run times in tests.
    """

    def __init__(
        self, timeout: float, callback_job: Callable[[], Coroutine[Any, None, None]]
    ) -> None:
        """Initialize the timer."""
        self._loop = asyncio.get_running_loop()
        self._timeout = timeout
        self._callback = callback_job
        self._task: asyncio.Task | None = None
        self._timer: asyncio.TimerHandle | None = None
        self._next_execute_time = 0.0

    def set_timeout(self, timeout: float) -> None:
        """Set a new timeout period."""
        self._timeout = timeout

    async def _async_job(self) -> None:
        """Execute after a cooldown period."""
        try:
            await self._callback()
        except HomeAssistantError as ha_error:
            _LOGGER.error("%s", ha_error)

    @callback
    def _async_task_done(self, task: asyncio.Task) -> None:
        """Handle task done."""
        self._task = None

    @callback
    def async_execute(self) -> asyncio.Task:
        """Execute the job."""
        if self._task:
            # Task already running,
            # so we schedule another run
            self.async_schedule()
            return self._task

        self._async_cancel_timer()
        self._task = create_eager_task(self._async_job())
        self._task.add_done_callback(self._async_task_done)
        return self._task

    @callback
    def _async_cancel_timer(self) -> None:
        """Cancel any pending task."""
        if self._timer:
            self._timer.cancel()
            self._timer = None

    @callback
    def async_schedule(self) -> None:
        """Ensure we execute after a cooldown period."""
        # We want to reschedule the timer in the future
        # every time this is called.
        next_when = self._loop.time() + self._timeout
        if not self._timer:
            self._timer = self._loop.call_at(next_when, self._async_timer_reached)
            return

        if self._timer.when() < next_when:
            # Timer already running, set the next execute time
            # if it fires too early, it will get rescheduled
            self._next_execute_time = next_when

    @callback
    def _async_timer_reached(self) -> None:
        """Handle timer fire."""
        self._timer = None
        if self._loop.time() >= self._next_execute_time:
            self.async_execute()
            return
        # Timer fired too early because there were multiple
        # calls async_schedule. Reschedule the timer.
        self._timer = self._loop.call_at(
            self._next_execute_time, self._async_timer_reached
        )

    async def async_cleanup(self) -> None:
        """Cleanup any pending task."""
        self._async_cancel_timer()
        if not self._task:
            return
        self._task.cancel()
        try:
            await self._task
        except asyncio.CancelledError:
            pass
        except Exception:
            _LOGGER.exception("Error cleaning up task")


def platforms_from_config(config: list[ConfigType]) -> set[Platform | str]:
    """Return the platforms to be set up."""
    return {key for platform in config for key in platform}


async def async_forward_entry_setup_and_setup_discovery(
    hass: HomeAssistant,
    config_entry: ConfigEntry,
    platforms: set[Platform | str],
    late: bool = False,
) -> None:
    """Forward the config entry setup to the platforms and set up discovery."""
    mqtt_data = hass.data[DATA_MQTT]
    platforms_loaded = mqtt_data.platforms_loaded
    new_platforms: set[Platform | str] = platforms - platforms_loaded
    tasks: list[asyncio.Task] = []
    if "device_automation" in new_platforms:
        # Local import to avoid circular dependencies
        # pylint: disable-next=import-outside-toplevel
        from . import device_automation

        tasks.append(
            create_eager_task(device_automation.async_setup_entry(hass, config_entry))
        )
    if "tag" in new_platforms:
        # Local import to avoid circular dependencies
        # pylint: disable-next=import-outside-toplevel
        from . import tag

        tasks.append(create_eager_task(tag.async_setup_entry(hass, config_entry)))
    if new_entity_platforms := (new_platforms - {"tag", "device_automation"}):
        tasks.append(
            create_eager_task(
                hass.config_entries.async_forward_entry_setups(
                    config_entry, new_entity_platforms
                )
            )
        )
    if not tasks:
        return
    await asyncio.gather(*tasks)
    platforms_loaded.update(new_platforms)


def mqtt_config_entry_enabled(hass: HomeAssistant) -> bool | None:
    """Return true when the MQTT config entry is enabled."""
    # If the mqtt client is connected, skip the expensive config
    # entry check as its roughly two orders of magnitude faster.
    return (
        DATA_MQTT in hass.data and hass.data[DATA_MQTT].client.connected
    ) or hass.config_entries.async_has_entries(
        DOMAIN, include_disabled=False, include_ignore=False
    )


async def async_wait_for_mqtt_client(hass: HomeAssistant) -> bool:
    """Wait for the MQTT client to become available.

    Waits when mqtt set up is in progress,
    It is not needed that the client is connected.
    Returns True if the mqtt client is available.
    Returns False when the client is not available.
    """
    if not mqtt_config_entry_enabled(hass):
        return False

    entry = hass.config_entries.async_entries(DOMAIN)[0]
    if entry.state == ConfigEntryState.LOADED:
        return True

    state_reached_future: asyncio.Future[bool]
    if DATA_MQTT_AVAILABLE not in hass.data:
        state_reached_future = hass.loop.create_future()
        hass.data[DATA_MQTT_AVAILABLE] = state_reached_future
    else:
        state_reached_future = hass.data[DATA_MQTT_AVAILABLE]

    try:
        async with asyncio.timeout(AVAILABILITY_TIMEOUT):
            # Await the client setup or an error state was received
            return await state_reached_future
    except TimeoutError:
        return False


def valid_topic(topic: Any) -> str:
    """Validate that this is a valid topic name/filter.

    This function is not cached and is not expected to be called
    directly outside of this module. It is not marked as protected
    only because its tested directly in test_util.py.

    If it gets used outside of valid_subscribe_topic and
    valid_publish_topic, it may need an lru_cache decorator or
    an lru_cache decorator on the function where its used.
    """
    validated_topic = cv.string(topic)
    try:
        raw_validated_topic = validated_topic.encode("utf-8")
    except UnicodeError as err:
        raise vol.Invalid("MQTT topic name/filter must be valid UTF-8 string.") from err
    if not raw_validated_topic:
        raise vol.Invalid("MQTT topic name/filter must not be empty.")
    if len(raw_validated_topic) > 65535:
        raise vol.Invalid(
            "MQTT topic name/filter must not be longer than 65535 encoded bytes."
        )

    for char in validated_topic:
        if char == "\0":
            raise vol.Invalid("MQTT topic name/filter must not contain null character.")
        if char <= "\u001f" or "\u007f" <= char <= "\u009f":
            raise vol.Invalid(
                "MQTT topic name/filter must not contain control characters."
            )
        if "\ufdd0" <= char <= "\ufdef" or (ord(char) & 0xFFFF) in (0xFFFE, 0xFFFF):
            raise vol.Invalid("MQTT topic name/filter must not contain non-characters.")

    return validated_topic


@lru_cache
def valid_subscribe_topic(topic: Any) -> str:
    """Validate that we can subscribe using this MQTT topic."""
    validated_topic = valid_topic(topic)
    if "+" in validated_topic:
        for i in (i for i, c in enumerate(validated_topic) if c == "+"):
            if (i > 0 and validated_topic[i - 1] != "/") or (
                i < len(validated_topic) - 1 and validated_topic[i + 1] != "/"
            ):
                raise vol.Invalid(
                    "Single-level wildcard must occupy an entire level of the filter"
                )

    index = validated_topic.find("#")
    if index != -1:
        if index != len(validated_topic) - 1:
            # If there are multiple wildcards, this will also trigger
            raise vol.Invalid(
                "Multi-level wildcard must be the last character in the topic filter."
            )
        if len(validated_topic) > 1 and validated_topic[index - 1] != "/":
            raise vol.Invalid(
                "Multi-level wildcard must be after a topic level separator."
            )

    return validated_topic


def valid_subscribe_topic_template(value: Any) -> template.Template:
    """Validate either a jinja2 template or a valid MQTT subscription topic."""
    tpl = cv.template(value)

    if tpl.is_static:
        valid_subscribe_topic(value)

    return tpl


@lru_cache
def valid_publish_topic(topic: Any) -> str:
    """Validate that we can publish using this MQTT topic."""
    validated_topic = valid_topic(topic)
    if "+" in validated_topic or "#" in validated_topic:
        raise vol.Invalid("Wildcards cannot be used in topic names")
    return validated_topic


def valid_qos_schema(qos: Any) -> int:
    """Validate that QOS value is valid."""
    validated_qos: int = _VALID_QOS_SCHEMA(qos)
    return validated_qos


_MQTT_WILL_BIRTH_SCHEMA = vol.Schema(
    {
        vol.Required(ATTR_TOPIC): valid_publish_topic,
        vol.Required(ATTR_PAYLOAD): cv.string,
        vol.Optional(ATTR_QOS, default=DEFAULT_QOS): valid_qos_schema,
        vol.Optional(ATTR_RETAIN, default=DEFAULT_RETAIN): cv.boolean,
    },
    required=True,
)


def valid_birth_will(config: ConfigType) -> ConfigType:
    """Validate a birth or will configuration and required topic/payload."""
    if config:
        config = _MQTT_WILL_BIRTH_SCHEMA(config)
    return config


async def async_create_certificate_temp_files(
    hass: HomeAssistant, config: ConfigType
) -> None:
    """Create certificate temporary files for the MQTT client."""

    def _create_temp_file(temp_file: Path, data: str | None) -> None:
        if data is None or data == "auto":
            if temp_file.exists():
                os.remove(Path(temp_file))
            return
        temp_file.write_text(data)

    def _create_temp_dir_and_files() -> None:
        """Create temporary directory."""
        temp_dir = Path(tempfile.gettempdir()) / TEMP_DIR_NAME

        if (
            config.get(CONF_CERTIFICATE)
            or config.get(CONF_CLIENT_CERT)
            or config.get(CONF_CLIENT_KEY)
        ) and not temp_dir.exists():
            temp_dir.mkdir(0o700)

        _create_temp_file(temp_dir / CONF_CERTIFICATE, config.get(CONF_CERTIFICATE))
        _create_temp_file(temp_dir / CONF_CLIENT_CERT, config.get(CONF_CLIENT_CERT))
        _create_temp_file(temp_dir / CONF_CLIENT_KEY, config.get(CONF_CLIENT_KEY))

    await hass.async_add_executor_job(_create_temp_dir_and_files)


def check_state_too_long(
    logger: logging.Logger, proposed_state: str, entity_id: str, msg: ReceiveMessage
) -> bool:
    """Check if the processed state is too long and log warning."""
    if (state_length := len(proposed_state)) > MAX_LENGTH_STATE_STATE:
        logger.warning(
            "Cannot update state for entity %s after processing "
            "payload on topic %s. The requested state (%s) exceeds "
            "the maximum allowed length (%s). Fall back to "
            "%s, failed state: %s",
            entity_id,
            msg.topic,
            state_length,
            MAX_LENGTH_STATE_STATE,
            STATE_UNKNOWN,
            proposed_state[:8192],
        )
        return True

    return False


def get_file_path(option: str, default: str | None = None) -> str | None:
    """Get file path of a certificate file."""
    temp_dir = Path(tempfile.gettempdir()) / TEMP_DIR_NAME
    if not temp_dir.exists():
        return default

    file_path: Path = temp_dir / option
    if not file_path.exists():
        return default

    return str(temp_dir / option)


def migrate_certificate_file_to_content(file_name_or_auto: str) -> str | None:
    """Convert certificate file or setting to config entry setting."""
    if file_name_or_auto == "auto":
        return "auto"
    try:
        with open(file_name_or_auto, encoding=DEFAULT_ENCODING) as certificate_file:
            return certificate_file.read()
    except OSError:
        return None