//! Bluetooth LE advertising.

use dbus::{
    arg::{PropMap, RefArg, Variant},
    nonblock::Proxy,
};
use dbus_crossroads::{Crossroads, IfaceBuilder, IfaceToken};
use futures::channel::oneshot;
use std::{
    collections::{BTreeMap, BTreeSet, HashMap},
    fmt,
    sync::Arc,
    time::Duration,
};
use strum::{Display, EnumString};
use uuid::Uuid;

use crate::{read_dict, Adapter, Result, SessionInner, SERVICE_NAME, TIMEOUT};

pub(crate) const MANAGER_INTERFACE: &str = "org.bluez.LEAdvertisingManager1";
pub(crate) const ADVERTISEMENT_INTERFACE: &str = "org.bluez.LEAdvertisement1";
pub(crate) const ADVERTISEMENT_PREFIX: &str = publish_path!("advertising/");

/// Determines the type of advertising packet requested.
#[derive(Clone, Copy, Debug, Eq, PartialEq, PartialOrd, Ord, Hash, Display, EnumString)]
pub enum Type {
    /// Broadcast
    #[strum(serialize = "broadcast")]
    Broadcast,
    /// Peripheral
    #[strum(serialize = "peripheral")]
    Peripheral,
}

impl Default for Type {
    fn default() -> Self {
        Self::Peripheral
    }
}

/// Secondary channel for advertisement.
#[derive(Clone, Copy, Debug, Eq, PartialEq, PartialOrd, Ord, Hash, Display, EnumString)]
#[non_exhaustive]
pub enum SecondaryChannel {
    /// 1M
    #[strum(serialize = "1M")]
    OneM,
    /// 2M
    #[strum(serialize = "2M")]
    TwoM,
    /// Coded
    #[strum(serialize = "Coded")]
    Coded,
}

impl Default for SecondaryChannel {
    fn default() -> Self {
        Self::OneM
    }
}

/// Advertisement feature.
#[derive(Clone, Copy, Debug, Eq, PartialEq, PartialOrd, Ord, Hash, Display, EnumString)]
#[non_exhaustive]
pub enum Feature {
    /// TX power.
    #[strum(serialize = "tx-power")]
    TxPower,
    /// Appearance.
    #[strum(serialize = "appearance")]
    Appearance,
    /// Local name.
    #[strum(serialize = "local-name")]
    LocalName,
}

/// LE advertising platform feature.
#[derive(Clone, Copy, Debug, Eq, PartialEq, PartialOrd, Ord, Hash, Display, EnumString)]
#[non_exhaustive]
pub enum PlatformFeature {
    /// Indicates whether platform can
    /// specify TX power on each
    /// advertising instance.
    #[strum(serialize = "CanSetTxPower")]
    CanSetTxPower,
    /// Indicates whether multiple
    /// advertising will be offloaded
    /// to the controller.
    #[strum(serialize = "HardwareOffload")]
    HardwareOffload,
}

/// Advertising-related controller capabilities.
#[derive(Clone, Debug, Default, Eq, PartialEq, PartialOrd, Ord, Hash)]
#[non_exhaustive]
pub struct Capabilities {
    /// Maximum advertising data length.
    pub max_advertisement_length: u8,
    /// Maximum advertising scan response length.
    pub max_scan_response_length: u8,
    /// Minimum advertising TX power (dBm).
    pub min_tx_power: i16,
    /// Maximum advertising TX power (dBm).
    pub max_tx_power: i16,
}

impl Capabilities {
    pub(crate) fn from_dict(dict: &HashMap<String, Variant<Box<dyn RefArg + 'static>>>) -> Result<Self> {
        Ok(Self {
            max_advertisement_length: *read_dict(dict, "MaxAdvLen")?,
            max_scan_response_length: *read_dict(dict, "MaxScnRspLen")?,
            min_tx_power: *read_dict(dict, "MinTxPower")?,
            max_tx_power: *read_dict(dict, "MaxTxPower")?,
        })
    }
}

/// Bluetooth LE advertisement data definition.
///
/// Specifies the Advertisement Data to be broadcast and some advertising
/// parameters.  Properties which are not present will not be included in the
/// data.  Required advertisement data types will always be included.
/// All UUIDs are 128-bit versions in the API, and 16 or 32-bit
/// versions of the same UUID will be used in the advertising data as appropriate.
///
/// Use [Adapter::advertise] to register a new advertisement.
#[derive(Clone, Debug, Default, Eq, PartialEq, PartialOrd, Ord, Hash)]
pub struct Advertisement {
    /// Determines the type of advertising packet requested.
    pub advertisement_type: Type,
    /// List of UUIDs to include in the "Service UUID" field of
    /// the Advertising Data.
    pub service_uuids: BTreeSet<Uuid>,
    /// Manufacturer Data fields to include in
    /// the Advertising Data.
    ///
    /// Keys are the Manufacturer ID
    /// to associate with the data.
    pub manufacturer_data: BTreeMap<u16, Vec<u8>>,
    /// Array of UUIDs to include in "Service Solicitation"
    /// Advertisement Data.
    pub solicit_uuids: BTreeSet<Uuid>,
    /// Service Data elements to include.
    ///
    /// The keys are the
    /// UUID to associate with the data.
    pub service_data: BTreeMap<Uuid, Vec<u8>>,
    /// Advertising Type to include in the Advertising
    /// Data.
    ///
    /// Key is the advertising type and value is the
    /// data as byte array.
    ///
    /// Note: Types already handled by other properties shall
    /// not be used.
    pub advertisting_data: BTreeMap<u8, Vec<u8>>,
    /// Advertise as general discoverable.
    ///
    /// When present this
    /// will override adapter Discoverable property.
    ///
    /// Note: This property shall not be set when Type is set
    /// to broadcast.
    pub discoverable: Option<bool>,
    /// The discoverable timeout in seconds.
    ///
    /// A value of zero
    /// means that the timeout is disabled and it will stay in
    /// discoverable/limited mode forever.
    ///
    /// Note: This property shall not be set when Type is set
    /// to broadcast.
    pub discoverable_timeout: Option<Duration>,
    /// List of system features to be included in the advertising
    /// packet.
    pub system_includes: BTreeSet<Feature>,
    /// Local name to be used in the advertising report.
    ///
    /// If the
    /// string is too big to fit into the packet it will be
    /// truncated.
    pub local_name: Option<String>,
    /// Appearance to be used in the advertising report.
    pub appearance: Option<u16>,
    /// Duration of the advertisement in seconds.
    ///
    /// If there are
    /// other applications advertising no duration is set the
    /// default is 2 seconds.
    pub duration: Option<Duration>,
    /// Timeout of the advertisement in seconds.
    ///
    /// This defines
    /// the lifetime of the advertisement.
    pub timeout: Option<Duration>,
    /// Secondary channel to be used.
    ///
    /// Primary channel is
    /// always set to "1M" except when "Coded" is set.
    pub secondary_channel: Option<SecondaryChannel>,
    /// Minimum advertising interval to be used by the
    /// advertising set, in milliseconds.
    ///
    /// Acceptable values
    /// are in the range [20ms, 10,485s]. If the provided
    /// MinInterval is larger than the provided MaxInterval,
    /// the registration will return failure.
    pub min_interval: Option<Duration>,
    /// Maximum advertising interval to be used by the
    /// advertising set, in milliseconds.
    ///
    /// Acceptable values
    /// are in the range [20ms, 10,485s]. If the provided
    /// MinInterval is larger than the provided MaxInterval,
    /// the registration will return failure.
    pub max_interval: Option<Duration>,
    /// Requested transmission power of this advertising set.
    ///
    /// The provided value is used only if the "CanSetTxPower"
    /// feature is enabled on the Advertising Manager. The
    /// provided value must be in range [-127 to +20], where
    /// units are in dBm.
    pub tx_power: Option<i16>,
    #[doc(hidden)]
    pub _non_exhaustive: (),
}

impl Advertisement {
    pub(crate) fn register_interface(cr: &mut Crossroads) -> IfaceToken<Self> {
        cr.register(ADVERTISEMENT_INTERFACE, |ib: &mut IfaceBuilder<Self>| {
            cr_property!(ib, "Type", la => {
                Some(la.advertisement_type.to_string())
            });
            cr_property!(ib, "ServiceUUIDs", la => {
                Some(la.service_uuids.iter().map(|uuid| uuid.to_string()).collect::<Vec<_>>())
            });
            cr_property!(ib, "ManufacturerData", la => {
                Some(la.manufacturer_data.clone().into_iter().map(|(k, v)| (k, Variant(v))).collect::<HashMap<_, _>>())
            });
            cr_property!(ib, "SolicitUUIDs", la => {
                Some(la.solicit_uuids.iter().map(|uuid| uuid.to_string()).collect::<Vec<_>>())
            });
            cr_property!(ib, "ServiceData", la => {
                Some(la.service_data.iter().map(|(k, v)| (k.to_string(), Variant(v.clone()))).collect::<HashMap<_, _>>())
            });
            cr_property!(ib, "Data", la => {
                Some(la.advertisting_data.clone().into_iter().collect::<HashMap<_, _>>())
            });
            cr_property!(ib, "Discoverable", la => {
                la.discoverable
            });
            cr_property!(ib, "DiscoverableTimeout", la => {
                la.discoverable_timeout.map(|t| t.as_secs().min(u16::MAX as _) as u16)
            });
            cr_property!(ib, "Includes", la => {
                Some(la.system_includes.iter().map(|v| v.to_string()).collect::<Vec<_>>())
            });
            cr_property!(ib, "LocalName", la => {
                la.local_name.clone()
            });
            cr_property!(ib, "Appearance", la => {
                la.appearance
            });
            cr_property!(ib, "Duration", la => {
                la.duration.map(|t| t.as_secs().min(u16::MAX as _) as u16)
            });
            cr_property!(ib, "Timeout", la => {
                la.timeout.map(|t| t.as_secs().min(u16::MAX as _) as u16)
            });
            cr_property!(ib, "SecondaryChannel", la => {
                la.secondary_channel.map(|v| v.to_string())
            });
            cr_property!(ib, "MinInterval", la => {
                la.min_interval.map(|t| t.as_millis().min(u32::MAX as _) as u32)
            });
            cr_property!(ib, "MaxInterval", la => {
                la.max_interval.map(|t| t.as_millis().min(u32::MAX as _) as u32)
            });
            cr_property!(ib, "TxPower", la => {
                la.tx_power
            });
        })
    }

    pub(crate) async fn register(
        self, inner: Arc<SessionInner>, adapter_name: Arc<String>,
    ) -> Result<AdvertisementHandle> {
        let name = dbus::Path::new(format!("{}{}", ADVERTISEMENT_PREFIX, Uuid::new_v4().to_simple())).unwrap();
        log::trace!("Publishing advertisement at {}", &name);

        {
            let mut cr = inner.crossroads.lock().await;
            cr.insert(name.clone(), &[inner.le_advertisment_token], self);
        }

        log::trace!("Registering advertisement at {}", &name);
        let proxy =
            Proxy::new(SERVICE_NAME, Adapter::dbus_path(&*adapter_name)?, TIMEOUT, inner.connection.clone());
        proxy.method_call(MANAGER_INTERFACE, "RegisterAdvertisement", (name.clone(), PropMap::new())).await?;

        let (drop_tx, drop_rx) = oneshot::channel();
        let unreg_name = name.clone();
        tokio::spawn(async move {
            let _ = drop_rx.await;

            log::trace!("Unregistering advertisement at {}", &unreg_name);
            let _: std::result::Result<(), dbus::Error> =
                proxy.method_call(MANAGER_INTERFACE, "UnregisterAdvertisement", (unreg_name.clone(),)).await;

            log::trace!("Unpublishing advertisement at {}", &unreg_name);
            let mut cr = inner.crossroads.lock().await;
            let _: Option<Self> = cr.remove(&unreg_name);
        });

        Ok(AdvertisementHandle { name, _drop_tx: drop_tx })
    }
}

/// Handle to active Bluetooth LE advertisement.
///
/// Drop to unregister advertisement.
pub struct AdvertisementHandle {
    name: dbus::Path<'static>,
    _drop_tx: oneshot::Sender<()>,
}

impl Drop for AdvertisementHandle {
    fn drop(&mut self) {
        // required for drop order
    }
}

impl fmt::Debug for AdvertisementHandle {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        write!(f, "AdvertisementHandle {{ {} }}", &self.name)
    }
}