// Take a look at the license at the top of the repository in the LICENSE file.

use std::num::NonZeroU32;

use glib::translate::*;

use crate::{BusNameOwnerFlags, BusNameWatcherFlags, BusType, DBusConnection};

#[derive(Debug, Eq, PartialEq)]
pub struct OwnerId(NonZeroU32);
#[derive(Debug, Eq, PartialEq)]
pub struct WatcherId(NonZeroU32);

fn own_closure<F>(f: F) -> glib::Closure
where
    F: Fn(DBusConnection, &str) + Send + Sync + 'static,
{
    glib::Closure::new(move |args| {
        let conn = args[0].get::<DBusConnection>().unwrap();
        let name = args[1].get::<&str>().unwrap();
        f(conn, name);
        None
    })
}

fn appeared_closure<F>(f: F) -> glib::Closure
where
    F: Fn(DBusConnection, &str, &str) + Send + Sync + 'static,
{
    glib::Closure::new(move |args| {
        let conn = args[0].get::<DBusConnection>().unwrap();
        let name = args[1].get::<&str>().unwrap();
        let name_owner = args[2].get::<&str>().unwrap();
        f(conn, name, name_owner);
        None
    })
}

fn vanished_closure<F>(f: F) -> glib::Closure
where
    F: Fn(DBusConnection, &str) + Send + Sync + 'static,
{
    glib::Closure::new(move |args| {
        let conn = args[0].get::<DBusConnection>().unwrap();
        let name = args[1].get::<&str>().unwrap();
        f(conn, name);
        None
    })
}

/// Like `g_bus_own_name()` but takes a [`DBusConnection`][crate::DBusConnection] instead of a
/// [`BusType`][crate::BusType].
/// ## `connection`
/// a [`DBusConnection`][crate::DBusConnection]
/// ## `name`
/// the well-known name to own
/// ## `flags`
/// a set of flags from the [`BusNameOwnerFlags`][crate::BusNameOwnerFlags] enumeration
/// ## `name_acquired_handler`
/// handler to invoke when `name` is acquired or [`None`]
/// ## `name_lost_handler`
/// handler to invoke when `name` is lost or [`None`]
///
/// # Returns
///
/// an identifier (never 0) that can be used with
///  `g_bus_unown_name()` to stop owning the name
#[doc(alias = "g_bus_own_name_on_connection_with_closures")]
pub fn bus_own_name_on_connection<NameAcquired, NameLost>(
    connection: &DBusConnection,
    name: &str,
    flags: BusNameOwnerFlags,
    name_acquired: NameAcquired,
    name_lost: NameLost,
) -> OwnerId
where
    NameAcquired: Fn(DBusConnection, &str) + Send + Sync + 'static,
    NameLost: Fn(DBusConnection, &str) + Send + Sync + 'static,
{
    unsafe {
        let id = ffi::g_bus_own_name_on_connection_with_closures(
            connection.to_glib_none().0,
            name.to_glib_none().0,
            flags.into_glib(),
            own_closure(name_acquired).to_glib_none().0,
            own_closure(name_lost).to_glib_none().0,
        );
        OwnerId(NonZeroU32::new_unchecked(id))
    }
}

/// Starts acquiring `name` on the bus specified by `bus_type` and calls
/// `name_acquired_handler` and `name_lost_handler` when the name is
/// acquired respectively lost. Callbacks will be invoked in the
/// [thread-default main context][g-main-context-push-thread-default]
/// of the thread you are calling this function from.
///
/// You are guaranteed that one of the `name_acquired_handler` and `name_lost_handler`
/// callbacks will be invoked after calling this function - there are three
/// possible cases:
///
/// - `name_lost_handler` with a [`None`] connection (if a connection to the bus
///  can't be made).
///
/// - `bus_acquired_handler` then `name_lost_handler` (if the name can't be
///  obtained)
///
/// - `bus_acquired_handler` then `name_acquired_handler` (if the name was
///  obtained).
///
/// When you are done owning the name, just call `g_bus_unown_name()`
/// with the owner id this function returns.
///
/// If the name is acquired or lost (for example another application
/// could acquire the name if you allow replacement or the application
/// currently owning the name exits), the handlers are also invoked.
/// If the [`DBusConnection`][crate::DBusConnection] that is used for attempting to own the name
/// closes, then `name_lost_handler` is invoked since it is no longer
/// possible for other processes to access the process.
///
/// You cannot use `g_bus_own_name()` several times for the same name (unless
/// interleaved with calls to `g_bus_unown_name()`) - only the first call
/// will work.
///
/// Another guarantee is that invocations of `name_acquired_handler`
/// and `name_lost_handler` are guaranteed to alternate; that
/// is, if `name_acquired_handler` is invoked then you are
/// guaranteed that the next time one of the handlers is invoked, it
/// will be `name_lost_handler`. The reverse is also true.
///
/// If you plan on exporting objects (using e.g.
/// `g_dbus_connection_register_object()`), note that it is generally too late
/// to export the objects in `name_acquired_handler`. Instead, you can do this
/// in `bus_acquired_handler` since you are guaranteed that this will run
/// before `name` is requested from the bus.
///
/// This behavior makes it very simple to write applications that wants
/// to [own names][gdbus-owning-names] and export objects.
/// Simply register objects to be exported in `bus_acquired_handler` and
/// unregister the objects (if any) in `name_lost_handler`.
/// ## `bus_type`
/// the type of bus to own a name on
/// ## `name`
/// the well-known name to own
/// ## `flags`
/// a set of flags from the [`BusNameOwnerFlags`][crate::BusNameOwnerFlags] enumeration
/// ## `bus_acquired_handler`
/// handler to invoke when connected to the bus of type `bus_type` or [`None`]
/// ## `name_acquired_handler`
/// handler to invoke when `name` is acquired or [`None`]
/// ## `name_lost_handler`
/// handler to invoke when `name` is lost or [`None`]
///
/// # Returns
///
/// an identifier (never 0) that can be used with
///  `g_bus_unown_name()` to stop owning the name.
#[doc(alias = "g_bus_own_name_with_closures")]
pub fn bus_own_name<BusAcquired, NameAcquired, NameLost>(
    bus_type: BusType,
    name: &str,
    flags: BusNameOwnerFlags,
    bus_acquired: BusAcquired,
    name_acquired: NameAcquired,
    name_lost: NameLost,
) -> OwnerId
where
    BusAcquired: Fn(DBusConnection, &str) + Send + Sync + 'static,
    NameAcquired: Fn(DBusConnection, &str) + Send + Sync + 'static,
    NameLost: Fn(Option<DBusConnection>, &str) + Send + Sync + 'static,
{
    unsafe {
        let id = ffi::g_bus_own_name_with_closures(
            bus_type.into_glib(),
            name.to_glib_none().0,
            flags.into_glib(),
            own_closure(bus_acquired).to_glib_none().0,
            own_closure(name_acquired).to_glib_none().0,
            glib::Closure::new(move |args| {
                let conn = args[0].get::<Option<DBusConnection>>().unwrap();
                let name = args[1].get::<&str>().unwrap();
                name_lost(conn, name);
                None
            })
            .to_glib_none()
            .0,
        );
        OwnerId(NonZeroU32::new_unchecked(id))
    }
}

#[doc(alias = "g_bus_unown_name")]
pub fn bus_unown_name(owner_id: OwnerId) {
    unsafe {
        ffi::g_bus_unown_name(owner_id.0.into());
    }
}

/// Like `g_bus_watch_name()` but takes a [`DBusConnection`][crate::DBusConnection] instead of a
/// [`BusType`][crate::BusType].
/// ## `connection`
/// A [`DBusConnection`][crate::DBusConnection].
/// ## `name`
/// The name (well-known or unique) to watch.
/// ## `flags`
/// Flags from the [`BusNameWatcherFlags`][crate::BusNameWatcherFlags] enumeration.
/// ## `name_appeared_handler`
/// Handler to invoke when `name` is known to exist or [`None`].
/// ## `name_vanished_handler`
/// Handler to invoke when `name` is known to not exist or [`None`].
///
/// # Returns
///
/// An identifier (never 0) that can be used with
/// `g_bus_unwatch_name()` to stop watching the name.
#[doc(alias = "g_bus_watch_name_on_connection_with_closures")]
pub fn bus_watch_name_on_connection<NameAppeared, NameVanished>(
    connection: &DBusConnection,
    name: &str,
    flags: BusNameWatcherFlags,
    name_appeared: NameAppeared,
    name_vanished: NameVanished,
) -> WatcherId
where
    NameAppeared: Fn(DBusConnection, &str, &str) + Send + Sync + 'static,
    NameVanished: Fn(DBusConnection, &str) + Send + Sync + 'static,
{
    unsafe {
        let id = ffi::g_bus_watch_name_on_connection_with_closures(
            connection.to_glib_none().0,
            name.to_glib_none().0,
            flags.into_glib(),
            appeared_closure(name_appeared).to_glib_none().0,
            vanished_closure(name_vanished).to_glib_none().0,
        );
        WatcherId(NonZeroU32::new_unchecked(id))
    }
}

/// Starts watching `name` on the bus specified by `bus_type` and calls
/// `name_appeared_handler` and `name_vanished_handler` when the name is
/// known to have an owner respectively known to lose its
/// owner. Callbacks will be invoked in the
/// [thread-default main context][g-main-context-push-thread-default]
/// of the thread you are calling this function from.
///
/// You are guaranteed that one of the handlers will be invoked after
/// calling this function. When you are done watching the name, just
/// call `g_bus_unwatch_name()` with the watcher id this function
/// returns.
///
/// If the name vanishes or appears (for example the application owning
/// the name could restart), the handlers are also invoked. If the
/// [`DBusConnection`][crate::DBusConnection] that is used for watching the name disconnects, then
/// `name_vanished_handler` is invoked since it is no longer
/// possible to access the name.
///
/// Another guarantee is that invocations of `name_appeared_handler`
/// and `name_vanished_handler` are guaranteed to alternate; that
/// is, if `name_appeared_handler` is invoked then you are
/// guaranteed that the next time one of the handlers is invoked, it
/// will be `name_vanished_handler`. The reverse is also true.
///
/// This behavior makes it very simple to write applications that want
/// to take action when a certain [name exists][gdbus-watching-names].
/// Basically, the application should create object proxies in
/// `name_appeared_handler` and destroy them again (if any) in
/// `name_vanished_handler`.
/// ## `bus_type`
/// The type of bus to watch a name on.
/// ## `name`
/// The name (well-known or unique) to watch.
/// ## `flags`
/// Flags from the [`BusNameWatcherFlags`][crate::BusNameWatcherFlags] enumeration.
/// ## `name_appeared_handler`
/// Handler to invoke when `name` is known to exist or [`None`].
/// ## `name_vanished_handler`
/// Handler to invoke when `name` is known to not exist or [`None`].
///
/// # Returns
///
/// An identifier (never 0) that can be used with
/// `g_bus_unwatch_name()` to stop watching the name.
#[doc(alias = "g_bus_watch_name_with_closures")]
pub fn bus_watch_name<NameAppeared, NameVanished>(
    bus_type: BusType,
    name: &str,
    flags: BusNameWatcherFlags,
    name_appeared: NameAppeared,
    name_vanished: NameVanished,
) -> WatcherId
where
    NameAppeared: Fn(DBusConnection, &str, &str) + Send + Sync + 'static,
    NameVanished: Fn(DBusConnection, &str) + Send + Sync + 'static,
{
    unsafe {
        let id = ffi::g_bus_watch_name_with_closures(
            bus_type.into_glib(),
            name.to_glib_none().0,
            flags.into_glib(),
            appeared_closure(name_appeared).to_glib_none().0,
            vanished_closure(name_vanished).to_glib_none().0,
        );
        WatcherId(NonZeroU32::new_unchecked(id))
    }
}

#[doc(alias = "g_bus_unwatch_name")]
pub fn bus_unwatch_name(watcher_id: WatcherId) {
    unsafe {
        ffi::g_bus_unwatch_name(watcher_id.0.into());
    }
}