use std::ffi::c_void;
use std::os::raw::c_char;

pub type CudaStream = *mut c_void;
pub type CudaEvent = *mut c_void;
pub type CudaGraph = *mut c_void;
pub type CudaGraphExec = *mut c_void;

pub const CUDA_MEMCPY_H2D: i32 = 1;
pub const CUDA_MEMCPY_D2H: i32 = 2;
pub const CUDA_MEMCPY_D2D: i32 = 3;

pub const CUDA_SUCCESS: i32 = 0;
pub const CUDA_ERROR_OUT_OF_MEMORY: i32 = 2;

/// cudaStreamCaptureMode::cudaStreamCaptureModeGlobal
pub const CUDA_STREAM_CAPTURE_MODE_GLOBAL: i32 = 0;

unsafe extern "C" {
    // --- Device ---
    pub fn cudaGetDeviceCount(count: *mut i32) -> i32;
    pub fn cudaSetDevice(device: i32) -> i32;
    pub fn cudaGetDevice(device: *mut i32) -> i32;
    /// Takes a raw pointer; caller provides a heap buffer large enough for any CUDA version.
    pub fn cudaGetDeviceProperties(prop: *mut u8, device: i32) -> i32;
    pub fn cudaDeviceSynchronize() -> i32;

    // --- Memory ---
    pub fn cudaMalloc(devptr: *mut *mut u8, size: usize) -> i32;
    pub fn cudaFree(devptr: *mut u8) -> i32;
    pub fn cudaMallocHost(ptr: *mut *mut u8, size: usize) -> i32;
    pub fn cudaFreeHost(ptr: *mut u8) -> i32;
    pub fn cudaMemcpy(dst: *mut u8, src: *const u8, count: usize, kind: i32) -> i32;
    pub fn cudaMemcpyAsync(
        dst: *mut u8,
        src: *const u8,
        count: usize,
        kind: i32,
        stream: CudaStream,
    ) -> i32;
    pub fn cudaMemset(devptr: *mut u8, value: i32, count: usize) -> i32;

    // --- Stream ---
    pub fn cudaStreamCreate(stream: *mut CudaStream) -> i32;
    pub fn cudaStreamDestroy(stream: CudaStream) -> i32;
    pub fn cudaStreamSynchronize(stream: CudaStream) -> i32;

    // --- Error ---
    pub fn cudaGetLastError() -> i32;
    pub fn cudaGetErrorString(error: i32) -> *const c_char;

    // --- CUDA Graphs ---
    pub fn cudaStreamBeginCapture(stream: CudaStream, mode: i32) -> i32;
    pub fn cudaStreamEndCapture(stream: CudaStream, graph: *mut CudaGraph) -> i32;
    pub fn cudaGraphInstantiate(
        graph_exec: *mut CudaGraphExec,
        graph: CudaGraph,
        flags: u64,
    ) -> i32;
    pub fn cudaGraphLaunch(graph_exec: CudaGraphExec, stream: CudaStream) -> i32;
    pub fn cudaGraphDestroy(graph: CudaGraph) -> i32;
    pub fn cudaGraphExecDestroy(graph_exec: CudaGraphExec) -> i32;

    // --- Our test kernel ---
    pub fn launch_vecadd_f32(
        a: *const f32,
        b: *const f32,
        c: *mut f32,
        n: i32,
        stream: CudaStream,
    );
}