"""Config flow for Xiaomi Bluetooth integration."""
from __future__ import annotations

import dataclasses
from typing import Any

import voluptuous as vol
from xiaomi_ble import XiaomiBluetoothDeviceData as DeviceData
from xiaomi_ble.parser import EncryptionScheme

from homeassistant.components import onboarding
from homeassistant.components.bluetooth import (
    BluetoothServiceInfo,
    async_discovered_service_info,
)
from homeassistant.config_entries import ConfigFlow
from homeassistant.const import CONF_ADDRESS
from homeassistant.data_entry_flow import FlowResult

from .const import DOMAIN


@dataclasses.dataclass
class Discovery:
    """A discovered bluetooth device."""

    title: str
    discovery_info: BluetoothServiceInfo
    device: DeviceData


def _title(discovery_info: BluetoothServiceInfo, device: DeviceData) -> str:
    return device.title or device.get_device_name() or discovery_info.name


class XiaomiConfigFlow(ConfigFlow, domain=DOMAIN):
    """Handle a config flow for Xiaomi Bluetooth."""

    VERSION = 1

    def __init__(self) -> None:
        """Initialize the config flow."""
        self._discovery_info: BluetoothServiceInfo | None = None
        self._discovered_device: DeviceData | None = None
        self._discovered_devices: dict[str, Discovery] = {}

    async def async_step_bluetooth(
        self, discovery_info: BluetoothServiceInfo
    ) -> FlowResult:
        """Handle the bluetooth discovery step."""
        await self.async_set_unique_id(discovery_info.address)
        self._abort_if_unique_id_configured()
        device = DeviceData()
        if not device.supported(discovery_info):
            return self.async_abort(reason="not_supported")
        self._discovery_info = discovery_info
        self._discovered_device = device

        title = _title(discovery_info, device)
        self.context["title_placeholders"] = {"name": title}

        if device.encryption_scheme == EncryptionScheme.MIBEACON_LEGACY:
            return await self.async_step_get_encryption_key_legacy()
        if device.encryption_scheme == EncryptionScheme.MIBEACON_4_5:
            return await self.async_step_get_encryption_key_4_5()
        return await self.async_step_bluetooth_confirm()

    async def async_step_get_encryption_key_legacy(
        self, user_input: dict[str, Any] | None = None
    ) -> FlowResult:
        """Enter a legacy bindkey for a v2/v3 MiBeacon device."""
        assert self._discovery_info
        errors = {}

        if user_input is not None:
            bindkey = user_input["bindkey"]

            if len(bindkey) != 24:
                errors["bindkey"] = "expected_24_characters"
            else:
                device = DeviceData(bindkey=bytes.fromhex(bindkey))

                # If we got this far we already know supported will
                # return true so we don't bother checking that again
                # We just want to retry the decryption
                device.supported(self._discovery_info)

                if device.bindkey_verified:
                    return self.async_create_entry(
                        title=self.context["title_placeholders"]["name"],
                        data={"bindkey": bindkey},
                    )

                errors["bindkey"] = "decryption_failed"

        return self.async_show_form(
            step_id="get_encryption_key_legacy",
            description_placeholders=self.context["title_placeholders"],
            data_schema=vol.Schema({vol.Required("bindkey"): vol.All(str, vol.Strip)}),
            errors=errors,
        )

    async def async_step_get_encryption_key_4_5(
        self, user_input: dict[str, Any] | None = None
    ) -> FlowResult:
        """Enter a bindkey for a v4/v5 MiBeacon device."""
        assert self._discovery_info

        errors = {}

        if user_input is not None:
            bindkey = user_input["bindkey"]

            if len(bindkey) != 32:
                errors["bindkey"] = "expected_32_characters"
            else:
                device = DeviceData(bindkey=bytes.fromhex(bindkey))

                # If we got this far we already know supported will
                # return true so we don't bother checking that again
                # We just want to retry the decryption
                device.supported(self._discovery_info)

                if device.bindkey_verified:
                    return self.async_create_entry(
                        title=self.context["title_placeholders"]["name"],
                        data={"bindkey": bindkey},
                    )

                errors["bindkey"] = "decryption_failed"

        return self.async_show_form(
            step_id="get_encryption_key_4_5",
            description_placeholders=self.context["title_placeholders"],
            data_schema=vol.Schema({vol.Required("bindkey"): vol.All(str, vol.Strip)}),
            errors=errors,
        )

    async def async_step_bluetooth_confirm(
        self, user_input: dict[str, Any] | None = None
    ) -> FlowResult:
        """Confirm discovery."""
        if user_input is not None or not onboarding.async_is_onboarded(self.hass):
            return self.async_create_entry(
                title=self.context["title_placeholders"]["name"],
                data={},
            )

        self._set_confirm_only()
        return self.async_show_form(
            step_id="bluetooth_confirm",
            description_placeholders=self.context["title_placeholders"],
        )

    async def async_step_user(
        self, user_input: dict[str, Any] | None = None
    ) -> FlowResult:
        """Handle the user step to pick discovered device."""
        if user_input is not None:
            address = user_input[CONF_ADDRESS]
            await self.async_set_unique_id(address, raise_on_progress=False)
            discovery = self._discovered_devices[address]

            if discovery.device.encryption_scheme == EncryptionScheme.MIBEACON_LEGACY:
                self._discovery_info = discovery.discovery_info
                self.context["title_placeholders"] = {"name": discovery.title}
                return await self.async_step_get_encryption_key_legacy()

            if discovery.device.encryption_scheme == EncryptionScheme.MIBEACON_4_5:
                self._discovery_info = discovery.discovery_info
                self.context["title_placeholders"] = {"name": discovery.title}
                return await self.async_step_get_encryption_key_4_5()

            return self.async_create_entry(title=discovery.title, data={})

        current_addresses = self._async_current_ids()
        for discovery_info in async_discovered_service_info(self.hass):
            address = discovery_info.address
            if address in current_addresses or address in self._discovered_devices:
                continue
            device = DeviceData()
            if device.supported(discovery_info):
                self._discovered_devices[address] = Discovery(
                    title=_title(discovery_info, device),
                    discovery_info=discovery_info,
                    device=device,
                )

        if not self._discovered_devices:
            return self.async_abort(reason="no_devices_found")

        titles = {
            address: discovery.title
            for (address, discovery) in self._discovered_devices.items()
        }
        return self.async_show_form(
            step_id="user",
            data_schema=vol.Schema({vol.Required(CONF_ADDRESS): vol.In(titles)}),
        )