/*
Crafter®.Graphics
Copyright (C) 2026 Catcrafts®
catcrafts.net
*/

// JS bridge declarations for the DOM-mode WebGPU backend. Each function
// corresponds to one entry in `additional/dom-webgpu.js`. Handles are
// opaque uint32 cookies into the JS-side handle tables.

export module Crafter.Graphics:WebGPU;
#ifdef CRAFTER_GRAPHICS_WINDOW_DOM
import std;

export namespace Crafter {
    using WebGPUBufferRef         = std::uint32_t;
    using WebGPUTextureRef        = std::uint32_t;
    using WebGPUSamplerRef        = std::uint32_t;
    using WebGPUCommandEncoderRef = std::uint32_t; // unused as a real handle; just a marker type for portability
}

namespace Crafter::WebGPU {
    __attribute__((import_module("env"), import_name("wgpuGetCanvasWidth")))
    extern "C" std::int32_t wgpuGetCanvasWidth();
    __attribute__((import_module("env"), import_name("wgpuGetCanvasHeight")))
    extern "C" std::int32_t wgpuGetCanvasHeight();
    __attribute__((import_module("env"), import_name("wgpuSurfaceWidth")))
    extern "C" std::int32_t wgpuSurfaceWidth();
    __attribute__((import_module("env"), import_name("wgpuSurfaceHeight")))
    extern "C" std::int32_t wgpuSurfaceHeight();
    __attribute__((import_module("env"), import_name("wgpuInit")))
    extern "C" void wgpuInit();

    __attribute__((import_module("env"), import_name("wgpuCreateBuffer")))
    extern "C" std::uint32_t wgpuCreateBuffer(std::int32_t byteSize);
    __attribute__((import_module("env"), import_name("wgpuWriteBuffer")))
    extern "C" void wgpuWriteBuffer(std::uint32_t handle, const void* srcPtr, std::int32_t byteSize);
    __attribute__((import_module("env"), import_name("wgpuDestroyBuffer")))
    extern "C" void wgpuDestroyBuffer(std::uint32_t handle);

    __attribute__((import_module("env"), import_name("wgpuCreateAtlasTexture")))
    extern "C" std::uint32_t wgpuCreateAtlasTexture(std::int32_t w, std::int32_t h);
    __attribute__((import_module("env"), import_name("wgpuWriteAtlasRegion")))
    extern "C" void wgpuWriteAtlasRegion(std::uint32_t handle, const void* srcPtr,
                                         std::int32_t srcW, std::int32_t srcH,
                                         std::int32_t srcBytesPerRow,
                                         std::int32_t dstX, std::int32_t dstY,
                                         std::int32_t copyW, std::int32_t copyH);
    __attribute__((import_module("env"), import_name("wgpuDestroyTexture")))
    extern "C" void wgpuDestroyTexture(std::uint32_t handle);

    // General-purpose rgba8unorm 2D texture for material albedo etc.
    // Separate from the atlas path because atlas uses r8unorm + sub-region
    // writes; this one takes the whole image in one shot.
    __attribute__((import_module("env"), import_name("wgpuCreateImage2D")))
    extern "C" std::uint32_t wgpuCreateImage2D(std::int32_t w, std::int32_t h);
    __attribute__((import_module("env"), import_name("wgpuWriteImage2D")))
    extern "C" void wgpuWriteImage2D(std::uint32_t handle, const void* srcPtr,
                                     std::int32_t byteSize,
                                     std::int32_t w, std::int32_t h);

    // 2D texture array — `layerCount` rgba8unorm layers of identical (w × h).
    // Sampled via `texture_2d_array<f32>` in WGSL (UICustomBindingKind 3).
    // Used by Image2DArray<RGBA8> to stack per-material albedos for one
    // multi-material scene.
    __attribute__((import_module("env"), import_name("wgpuCreateImage2DArray")))
    extern "C" std::uint32_t wgpuCreateImage2DArray(std::int32_t w, std::int32_t h, std::int32_t layerCount);
    __attribute__((import_module("env"), import_name("wgpuWriteImage2DLayer")))
    extern "C" void wgpuWriteImage2DLayer(std::uint32_t handle, std::int32_t layer,
                                          const void* srcPtr, std::int32_t byteSize,
                                          std::int32_t w, std::int32_t h);

    __attribute__((import_module("env"), import_name("wgpuCreateLinearClampSampler")))
    extern "C" std::uint32_t wgpuCreateLinearClampSampler();

    __attribute__((import_module("env"), import_name("wgpuFrameBegin")))
    extern "C" void wgpuFrameBegin();
    __attribute__((import_module("env"), import_name("wgpuFrameEnd")))
    extern "C" void wgpuFrameEnd();

    __attribute__((import_module("env"), import_name("wgpuDispatchQuads")))
    extern "C" void wgpuDispatchQuads(std::uint32_t itemsHandle, const void* headerPtr,
                                      std::int32_t gx, std::int32_t gy);
    __attribute__((import_module("env"), import_name("wgpuDispatchCircles")))
    extern "C" void wgpuDispatchCircles(std::uint32_t itemsHandle, const void* headerPtr,
                                        std::int32_t gx, std::int32_t gy);
    __attribute__((import_module("env"), import_name("wgpuDispatchImages")))
    extern "C" void wgpuDispatchImages(std::uint32_t itemsHandle, const void* headerPtr,
                                       std::int32_t gx, std::int32_t gy,
                                       std::uint32_t texHandle, std::uint32_t sampHandle);
    __attribute__((import_module("env"), import_name("wgpuDispatchText")))
    extern "C" void wgpuDispatchText(std::uint32_t itemsHandle, const void* headerPtr,
                                     std::int32_t gx, std::int32_t gy,
                                     std::uint32_t atlasHandle, std::uint32_t sampHandle);

    // ─── custom user-authored compute shaders ───────────────────────────
    // rayQueryFlag = 1 swaps group(1) from the UI ping-pong pair to the RT
    // data heaps (TLAS, BVH, meshRecs, verts, idx, primRemap, outImage) and
    // prepends a WGSL prelude exposing the rayQuery* API. Shaders that set
    // this MUST NOT declare their own @group(1) bindings.
    __attribute__((import_module("env"), import_name("wgpuLoadCustomShader")))
    extern "C" std::uint32_t wgpuLoadCustomShader(const void* wgslPtr, std::int32_t wgslLen,
                                                  const void* bindingsPtr, std::int32_t bindingsCount,
                                                  std::int32_t rayQueryFlag);
    __attribute__((import_module("env"), import_name("wgpuDispatchCustom")))
    extern "C" void wgpuDispatchCustom(std::uint32_t pipelineHandle,
                                       const void* pushPtr, std::int32_t pushBytes,
                                       const void* handlesPtr, std::int32_t handlesCount,
                                       std::int32_t gx, std::int32_t gy, std::int32_t gz);

    // ─── software raytracing ───────────────────────────────────────────
    //
    // Mesh::Build forwards vertex / index / BVH-node / primRemap arrays
    // to the JS bridge, which queue.writeBuffers them into the global
    // RT mesh heaps (growing if needed) and records the per-mesh offsets
    // under a freshly-allocated u32 handle. The handle is what user code
    // stores in RTInstance::accelerationStructureReference; the WebGPU
    // TLAS-build compute shader resolves it back to root AABB + heap
    // offsets at dispatch time. Returns 0 on failure.
    // The optional `attribsPtr` / `attribsByteCount` carry per-vertex
    // attribute payload (normals, UVs, etc. — layout is example-defined)
    // that gets appended to a global attribs heap and exposed to RT
    // closest-hit shaders as `vertexAttribs : array<u32>` at
    // @group(1) @binding(7). Pass (nullptr, 0) for positions-only meshes.
    __attribute__((import_module("env"), import_name("wgpuRegisterMeshBLAS")))
    extern "C" std::uint32_t wgpuRegisterMeshBLAS(
        float minX, float minY, float minZ,
        float maxX, float maxY, float maxZ,
        const void* verticesPtr, std::int32_t vertexCount,
        const void* indicesPtr,  std::int32_t indexCount,
        const void* bvhNodesPtr, std::int32_t bvhNodeCount,
        const void* primRemapPtr, std::int32_t primRemapCount,
        const void* attribsPtr,  std::int32_t attribsByteCount);

    // RT pipeline build. The library composes WGSL by concatenating the
    // traversal library, generated hit-group switches, and the user-
    // supplied raygen / miss / closesthit / anyhit bodies. `bindings` is
    // UICustomBinding-shaped (8 bytes each) declaring extra @group(2)+
    // resources the user's closest-hit / miss / raygen WGSL references.
    // Pass (nullptr, 0) for a pipeline with no user-declared bindings.
    // Returns an opaque pipeline handle.
    __attribute__((import_module("env"), import_name("wgpuLoadRTPipeline")))
    extern "C" std::uint32_t wgpuLoadRTPipeline(const void* wgslPtr, std::int32_t wgslLen,
                                                const void* bindingsPtr, std::int32_t bindingsCount);

    // Dispatch a TraceRays-equivalent pass: the RT pipeline is dispatched
    // over a (gx, gy) tile grid; the library writes the push data (camera,
    // payload, etc. — opaque) into a uniform ring buffer, attaches the TLAS
    // + global mesh heap, and runs one workgroup per 8x8 screen tile.
    // `handles[]` carries resolved WebGPU resource handles for every user
    // binding declared at pipeline-load time, in the same order. Pass
    // (nullptr, 0) for a pipeline with no user bindings.
    __attribute__((import_module("env"), import_name("wgpuDispatchRT")))
    extern "C" void wgpuDispatchRT(std::uint32_t pipelineHandle,
                                   const void* pushPtr, std::int32_t pushBytes,
                                   std::uint32_t tlasBufHandle,
                                   std::int32_t  instanceCount,
                                   std::int32_t  gx, std::int32_t gy,
                                   const void* handlesPtr, std::int32_t handlesCount);

    // GPU TLAS-build dispatch. Reads the instance buffer (host-uploaded or
    // GPU-written), produces per-instance world-space AABBs + per-instance
    // transform matrices in a flat tlasBuf SSBO consumed by traceRay / rayQuery.
    __attribute__((import_module("env"), import_name("wgpuBuildTLAS")))
    extern "C" void wgpuBuildTLAS(std::uint32_t instanceBufHandle,
                                  std::int32_t  instanceCount,
                                  std::uint32_t tlasOutBufHandle);
}
#endif // CRAFTER_GRAPHICS_WINDOW_DOM