// Copyright 2018-2024 the Deno authors. All rights reserved. MIT license.

use deno_core::op2;
use deno_core::OpState;
use deno_core::ResourceId;
use std::ffi::c_void;
#[cfg(any(
    target_os = "linux",
    target_os = "macos",
    target_os = "freebsd",
    target_os = "openbsd"
))]
use std::ptr::NonNull;

use crate::surface::WebGpuSurface;

#[derive(Debug, thiserror::Error)]
pub enum ByowError {
    #[error("Cannot create surface outside of WebGPU context. Did you forget to call `navigator.gpu.requestAdapter()`?")]
    WebGPUNotInitiated,
    #[error("Invalid parameters")]
    InvalidParameters,
    #[error(transparent)]
    CreateSurface(wgpu_core::instance::CreateSurfaceError),
    #[cfg(target_os = "windows")]
    #[error("Invalid system on Windows")]
    InvalidSystem,
    #[cfg(target_os = "macos")]
    #[error("Invalid system on macOS")]
    InvalidSystem,
    #[cfg(any(target_os = "linux", target_os = "freebsd", target_os = "openbsd"))]
    #[error("Invalid system on Linux/BSD")]
    InvalidSystem,
    #[cfg(any(
        target_os = "windows",
        target_os = "linux",
        target_os = "freebsd",
        target_os = "openbsd"
    ))]
    #[error("window is null")]
    NullWindow,
    #[cfg(any(target_os = "linux", target_os = "freebsd", target_os = "openbsd"))]
    #[error("display is null")]
    NullDisplay,
    #[cfg(target_os = "macos")]
    #[error("ns_view is null")]
    NSViewDisplay,
}

#[op2(fast)]
#[smi]
pub fn op_webgpu_surface_create(
    state: &mut OpState,
    #[string] system: &str,
    p1: *const c_void,
    p2: *const c_void,
) -> Result<ResourceId, ByowError> {
    let instance = state
        .try_borrow::<super::Instance>()
        .ok_or(ByowError::WebGPUNotInitiated)?;
    // Security note:
    //
    // The `p1` and `p2` parameters are pointers to platform-specific window
    // handles.
    //
    // The code below works under the assumption that:
    //
    // - handles can only be created by the FFI interface which
    // enforces --allow-ffi.
    //
    // - `*const c_void` deserizalizes null and v8::External.
    //
    // - Only FFI can export v8::External to user code.
    if p1.is_null() {
        return Err(ByowError::InvalidParameters);
    }

    let (win_handle, display_handle) = raw_window(system, p1, p2)?;
    // SAFETY: see above comment
    let surface = unsafe {
        instance
            .instance_create_surface(display_handle, win_handle, None)
            .map_err(ByowError::CreateSurface)?
    };

    let rid = state
        .resource_table
        .add(WebGpuSurface(instance.clone(), surface));
    Ok(rid)
}

type RawHandles = (
    raw_window_handle::RawWindowHandle,
    raw_window_handle::RawDisplayHandle,
);

#[cfg(target_os = "macos")]
fn raw_window(
    system: &str,
    _ns_window: *const c_void,
    ns_view: *const c_void,
) -> Result<RawHandles, ByowError> {
    if system != "cocoa" {
        return Err(ByowError::InvalidSystem);
    }

    let win_handle =
        raw_window_handle::RawWindowHandle::AppKit(raw_window_handle::AppKitWindowHandle::new(
            NonNull::new(ns_view as *mut c_void).ok_or(ByowError::NSViewDisplay)?,
        ));

    let display_handle =
        raw_window_handle::RawDisplayHandle::AppKit(raw_window_handle::AppKitDisplayHandle::new());
    Ok((win_handle, display_handle))
}

#[cfg(target_os = "windows")]
fn raw_window(
    system: &str,
    window: *const c_void,
    hinstance: *const c_void,
) -> Result<RawHandles, ByowError> {
    use raw_window_handle::WindowsDisplayHandle;
    if system != "win32" {
        return Err(ByowError::InvalidSystem);
    }

    let win_handle = {
        let mut handle = raw_window_handle::Win32WindowHandle::new(
            std::num::NonZeroIsize::new(window as isize).ok_or(ByowError::NullWindow)?,
        );
        handle.hinstance = std::num::NonZeroIsize::new(hinstance as isize);

        raw_window_handle::RawWindowHandle::Win32(handle)
    };

    let display_handle = raw_window_handle::RawDisplayHandle::Windows(WindowsDisplayHandle::new());
    Ok((win_handle, display_handle))
}

#[cfg(any(target_os = "linux", target_os = "freebsd", target_os = "openbsd"))]
fn raw_window(
    system: &str,
    window: *const c_void,
    display: *const c_void,
) -> Result<RawHandles, ByowError> {
    let (win_handle, display_handle);
    if system == "x11" {
        win_handle = raw_window_handle::RawWindowHandle::Xlib(
            raw_window_handle::XlibWindowHandle::new(window as *mut c_void as _),
        );

        display_handle = raw_window_handle::RawDisplayHandle::Xlib(
            raw_window_handle::XlibDisplayHandle::new(NonNull::new(display as *mut c_void), 0),
        );
    } else if system == "wayland" {
        win_handle = raw_window_handle::RawWindowHandle::Wayland(
            raw_window_handle::WaylandWindowHandle::new(
                NonNull::new(window as *mut c_void).ok_or(ByowError::NullWindow)?,
            ),
        );

        display_handle = raw_window_handle::RawDisplayHandle::Wayland(
            raw_window_handle::WaylandDisplayHandle::new(
                NonNull::new(display as *mut c_void).ok_or(ByowError::NullDisplay)?,
            ),
        );
    } else {
        return Err(ByowError::InvalidSystem);
    }

    Ok((win_handle, display_handle))
}

#[cfg(not(any(
    target_os = "macos",
    target_os = "windows",
    target_os = "linux",
    target_os = "freebsd",
    target_os = "openbsd",
)))]
fn raw_window(
    _system: &str,
    _window: *const c_void,
    _display: *const c_void,
) -> Result<RawHandles, deno_core::error::AnyError> {
    Err(deno_core::error::type_error("Unsupported platform"))
}
