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

#[cfg(feature = "v1_16")]
#[cfg_attr(docsrs, doc(cfg(feature = "v1_16")))]
use std::boxed::Box as Box_;
#[cfg(feature = "v1_16")]
#[cfg_attr(docsrs, doc(cfg(feature = "v1_16")))]
use std::mem::transmute;
use std::{mem, ptr};

#[cfg(feature = "v1_16")]
#[cfg_attr(docsrs, doc(cfg(feature = "v1_16")))]
use glib::signal::{connect_raw, SignalHandlerId};
use glib::{prelude::*, translate::*};
use gst::{format::FormattedValue, prelude::*};

use crate::{ffi, Aggregator, AggregatorPad};

mod sealed {
    pub trait Sealed {}
    impl<T: super::IsA<super::Aggregator>> Sealed for T {}
}

pub trait AggregatorExtManual: sealed::Sealed + IsA<Aggregator> + 'static {
    /// Lets [`Aggregator`][crate::Aggregator] sub-classes get the memory `allocator`
    /// acquired by the base class and its `params`.
    ///
    /// Unref the `allocator` after use it.
    ///
    /// # Returns
    ///
    ///
    /// ## `allocator`
    /// the [`gst::Allocator`][crate::gst::Allocator]
    /// used
    ///
    /// ## `params`
    /// the
    /// [`gst::AllocationParams`][crate::gst::AllocationParams] of `allocator`
    #[doc(alias = "get_allocator")]
    #[doc(alias = "gst_aggregator_get_allocator")]
    fn allocator(&self) -> (Option<gst::Allocator>, gst::AllocationParams) {
        unsafe {
            let mut allocator = ptr::null_mut();
            let mut params = mem::MaybeUninit::uninit();
            ffi::gst_aggregator_get_allocator(
                self.as_ref().to_glib_none().0,
                &mut allocator,
                params.as_mut_ptr(),
            );
            (from_glib_full(allocator), params.assume_init().into())
        }
    }

    #[cfg(feature = "v1_16")]
    #[cfg_attr(docsrs, doc(cfg(feature = "v1_16")))]
    #[doc(alias = "min-upstream-latency")]
    fn min_upstream_latency(&self) -> gst::ClockTime {
        self.as_ref().property("min-upstream-latency")
    }

    #[cfg(feature = "v1_16")]
    #[cfg_attr(docsrs, doc(cfg(feature = "v1_16")))]
    #[doc(alias = "min-upstream-latency")]
    fn set_min_upstream_latency(&self, min_upstream_latency: gst::ClockTime) {
        self.as_ref()
            .set_property("min-upstream-latency", min_upstream_latency);
    }

    #[cfg(feature = "v1_16")]
    #[cfg_attr(docsrs, doc(cfg(feature = "v1_16")))]
    #[doc(alias = "min-upstream-latency")]
    fn connect_min_upstream_latency_notify<F: Fn(&Self) + Send + Sync + 'static>(
        &self,
        f: F,
    ) -> SignalHandlerId {
        unsafe {
            let f: Box_<F> = Box_::new(f);
            connect_raw(
                self.as_ptr() as *mut _,
                b"notify::min-upstream-latency\0".as_ptr() as *const _,
                Some(transmute::<*const (), unsafe extern "C" fn()>(
                    notify_min_upstream_latency_trampoline::<Self, F> as *const (),
                )),
                Box_::into_raw(f),
            )
        }
    }

    /// Subclasses should use this to update the segment on their
    /// source pad, instead of directly pushing new segment events
    /// downstream.
    ///
    /// Subclasses MUST call this before [`selected_samples()`][Self::selected_samples()],
    /// if it is used at all.
    #[cfg(feature = "v1_18")]
    #[cfg_attr(docsrs, doc(cfg(feature = "v1_18")))]
    #[doc(alias = "gst_aggregator_update_segment")]
    fn update_segment<F: gst::format::FormattedValueIntrinsic>(
        &self,
        segment: &gst::FormattedSegment<F>,
    ) {
        unsafe {
            ffi::gst_aggregator_update_segment(
                self.as_ref().to_glib_none().0,
                mut_override(segment.to_glib_none().0),
            )
        }
    }

    fn set_position(&self, position: impl FormattedValue) {
        unsafe {
            let ptr: *mut ffi::GstAggregator = self.as_ref().to_glib_none().0;
            let ptr = &mut *ptr;
            let _guard = self.as_ref().object_lock();

            // gstaggregator.c asserts that the src pad is always of type GST_TYPE_AGGREGATOR_PAD,
            // so the pointer cast here should be safe.
            let srcpad = &mut *(ptr.srcpad as *mut ffi::GstAggregatorPad);

            assert_eq!(srcpad.segment.format, position.format().into_glib());
            srcpad.segment.position = position.into_raw_value() as u64;
        }
    }

    /// Subclasses should call this when they have prepared the
    /// buffers they will aggregate for each of their sink pads, but
    /// before using any of the properties of the pads that govern
    /// *how* aggregation should be performed, for example z-index
    /// for video aggregators.
    ///
    /// If [`update_segment()`][Self::update_segment()] is used by the subclass,
    /// it MUST be called before [`selected_samples()`][Self::selected_samples()].
    ///
    /// This function MUST only be called from the `GstAggregatorClass::aggregate()`
    /// function.
    /// ## `pts`
    /// The presentation timestamp of the next output buffer
    /// ## `dts`
    /// The decoding timestamp of the next output buffer
    /// ## `duration`
    /// The duration of the next output buffer
    /// ## `info`
    /// a [`gst::Structure`][crate::gst::Structure] containing additional information
    #[cfg(feature = "v1_18")]
    #[cfg_attr(docsrs, doc(cfg(feature = "v1_18")))]
    #[doc(alias = "gst_aggregator_selected_samples")]
    fn selected_samples(
        &self,
        pts: impl Into<Option<gst::ClockTime>>,
        dts: impl Into<Option<gst::ClockTime>>,
        duration: impl Into<Option<gst::ClockTime>>,
        info: Option<&gst::StructureRef>,
    ) {
        unsafe {
            ffi::gst_aggregator_selected_samples(
                self.as_ref().to_glib_none().0,
                pts.into().into_glib(),
                dts.into().into_glib(),
                duration.into().into_glib(),
                info.as_ref()
                    .map(|s| s.as_ptr() as *mut _)
                    .unwrap_or(ptr::null_mut()),
            );
        }
    }

    #[cfg(feature = "v1_18")]
    #[cfg_attr(docsrs, doc(cfg(feature = "v1_18")))]
    fn connect_samples_selected<
        F: Fn(
                &Self,
                &gst::Segment,
                Option<gst::ClockTime>,
                Option<gst::ClockTime>,
                Option<gst::ClockTime>,
                Option<&gst::StructureRef>,
            ) + Send
            + 'static,
    >(
        &self,
        f: F,
    ) -> SignalHandlerId {
        unsafe extern "C" fn samples_selected_trampoline<
            P,
            F: Fn(
                    &P,
                    &gst::Segment,
                    Option<gst::ClockTime>,
                    Option<gst::ClockTime>,
                    Option<gst::ClockTime>,
                    Option<&gst::StructureRef>,
                ) + Send
                + 'static,
        >(
            this: *mut ffi::GstAggregator,
            segment: *mut gst::ffi::GstSegment,
            pts: gst::ffi::GstClockTime,
            dts: gst::ffi::GstClockTime,
            duration: gst::ffi::GstClockTime,
            info: *mut gst::ffi::GstStructure,
            f: glib::ffi::gpointer,
        ) where
            P: IsA<Aggregator>,
        {
            let f: &F = &*(f as *const F);
            f(
                Aggregator::from_glib_borrow(this).unsafe_cast_ref(),
                gst::Segment::from_glib_ptr_borrow(segment),
                from_glib(pts),
                from_glib(dts),
                from_glib(duration),
                if info.is_null() {
                    None
                } else {
                    Some(gst::StructureRef::from_glib_borrow(info))
                },
            )
        }

        unsafe {
            let f: Box_<F> = Box_::new(f);
            connect_raw(
                self.as_ptr() as *mut _,
                b"samples-selected\0".as_ptr() as *const _,
                Some(transmute::<*const (), unsafe extern "C" fn()>(
                    samples_selected_trampoline::<Self, F> as *const (),
                )),
                Box_::into_raw(f),
            )
        }
    }

    fn src_pad(&self) -> &AggregatorPad {
        unsafe {
            let elt = &*(self.as_ptr() as *const ffi::GstAggregator);
            &*(&elt.srcpad as *const *mut gst::ffi::GstPad as *const AggregatorPad)
        }
    }
}

impl<O: IsA<Aggregator>> AggregatorExtManual for O {}

#[cfg(feature = "v1_16")]
#[cfg_attr(docsrs, doc(cfg(feature = "v1_16")))]
unsafe extern "C" fn notify_min_upstream_latency_trampoline<P, F: Fn(&P) + Send + Sync + 'static>(
    this: *mut ffi::GstAggregator,
    _param_spec: glib::ffi::gpointer,
    f: glib::ffi::gpointer,
) where
    P: IsA<Aggregator>,
{
    let f: &F = &*(f as *const F);
    f(Aggregator::from_glib_borrow(this).unsafe_cast_ref())
}