// Copyright 2022 The ChromiumOS Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

use std::sync::Weak;

use base::AsRawDescriptor;
use base::RawDescriptor;
use base::ReadNotifier;
use base::SendTube;
use base::WaitContext;
use metrics::sys::windows::Metrics;

use crate::gpu_display_win::DisplayWin;
use crate::DisplayEventToken;
use crate::DisplayT;
use crate::EventDevice;
use crate::GpuDisplay;
use crate::GpuDisplayExt;
use crate::GpuDisplayResult;
use crate::VulkanCreateParams;
use crate::WindowProcedureThread;

pub(crate) trait WinDisplayT: DisplayT {
    /// Imports an event device into the display backend.
    fn import_event_device(
        &mut self,
        _event_device_id: u32,
        _event_device: EventDevice,
    ) -> GpuDisplayResult<()> {
        Ok(())
    }

    /// Called when the given event device is readable; in other words, when the guest sends data
    /// to the host (e.g. to set the numlock LED on/off).
    fn handle_event_device(&mut self, _event_device_id: u32) {}
}

impl GpuDisplayExt for GpuDisplay {
    fn import_event_device(&mut self, event_device: EventDevice) -> GpuDisplayResult<u32> {
        let new_event_device_id = self.next_id;

        // Safety (even though it's technically "safe"): event_device is owned by self.inner, and
        // will live until self.inner is dropped.
        self.wait_ctx.add(
            event_device.get_read_notifier(),
            DisplayEventToken::EventDevice {
                event_device_id: new_event_device_id,
            },
        )?;
        self.inner
            .import_event_device(new_event_device_id, event_device)?;

        self.next_id += 1;
        Ok(new_event_device_id)
    }

    fn handle_event_device(&mut self, event_device_id: u32) {
        self.inner.handle_event_device(event_device_id);
    }
}

pub trait WinGpuDisplayExt {
    fn open_winapi(
        wndproc_thread: WindowProcedureThread,
        win_metrics: Option<Weak<Metrics>>,
        gpu_display_wait_descriptor_ctrl: SendTube,
        vulkan_display_create_params: Option<VulkanCreateParams>,
    ) -> GpuDisplayResult<GpuDisplay>;
}

impl WinGpuDisplayExt for GpuDisplay {
    fn open_winapi(
        wndproc_thread: WindowProcedureThread,
        win_metrics: Option<Weak<Metrics>>,
        gpu_display_wait_descriptor_ctrl: SendTube,
        vulkan_display_create_params: Option<VulkanCreateParams>,
    ) -> GpuDisplayResult<GpuDisplay> {
        let display = DisplayWin::new(
            wndproc_thread,
            win_metrics,
            gpu_display_wait_descriptor_ctrl,
            vulkan_display_create_params,
        )?;

        let wait_ctx = WaitContext::new()?;
        wait_ctx.add(&display, DisplayEventToken::Display)?;

        Ok(GpuDisplay {
            inner: Box::new(display),
            next_id: 1,
            event_devices: Default::default(),
            surfaces: Default::default(),
            wait_ctx,
        })
    }
}

impl AsRawDescriptor for GpuDisplay {
    fn as_raw_descriptor(&self) -> RawDescriptor {
        self.inner.as_raw_descriptor()
    }
}