// Copyright 2021 The IREE Authors
//
// Licensed under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception

#include "experimental/webgpu/webgpu_device.h"

#include <stddef.h>
#include <stdint.h>
#include <string.h>

#include "experimental/webgpu/bind_group_cache.h"
#include "experimental/webgpu/builtins.h"
#include "experimental/webgpu/command_buffer.h"
#include "experimental/webgpu/nop_event.h"
#include "experimental/webgpu/nop_executable_cache.h"
#include "experimental/webgpu/nop_semaphore.h"
#include "experimental/webgpu/pipeline_layout.h"
#include "experimental/webgpu/simple_allocator.h"
#include "experimental/webgpu/staging_buffer.h"
#include "iree/base/internal/arena.h"
#include "iree/hal/utils/buffer_transfer.h"

//===----------------------------------------------------------------------===//
// iree_hal_webgpu_device_t
//===----------------------------------------------------------------------===//

#define IREE_HAL_WEBGPU_SMALL_POOL_BLOCK_SIZE (4 * 1024)
#define IREE_HAL_WEBGPU_LARGE_POOL_BLOCK_SIZE (32 * 1024)

IREE_API_EXPORT void iree_hal_webgpu_device_options_initialize(
    iree_hal_webgpu_device_options_t* out_options) {
  IREE_ASSERT_ARGUMENT(out_options);
  out_options->flags = IREE_HAL_WEBGPU_DEVICE_RESERVED;
  out_options->queue_uniform_buffer_size =
      IREE_HAL_WEBGPU_STAGING_BUFFER_DEFAULT_CAPACITY;
}

typedef struct iree_hal_webgpu_device_t {
  iree_hal_resource_t resource;
  iree_allocator_t host_allocator;
  iree_string_view_t identifier;

  bool owns_device_handle;
  WGPUDevice handle;
  WGPUQueue queue;

  // Block pool used for small allocations like submissions and callbacks.
  iree_arena_block_pool_t small_block_pool;
  // Block pool used for command buffers with a large block size (as command
  // buffers can contain inlined data uploads).
  iree_arena_block_pool_t large_block_pool;

  iree_hal_allocator_t* device_allocator;

  // Builtin shaders emulating functionality not present in WebGPU.
  iree_hal_webgpu_builtins_t builtins;

  // Cached bind groups used during command buffer recording.
  iree_hal_webgpu_bind_group_cache_t bind_group_cache;

  // Staging buffer for parameter uploads.
  // Host storage is allocated as part of the device structure.
  iree_hal_webgpu_staging_buffer_t staging_buffer;
  uint8_t staging_buffer_host_data[];
} iree_hal_webgpu_device_t;

extern const iree_hal_device_vtable_t iree_hal_webgpu_device_vtable;

static iree_hal_webgpu_device_t* iree_hal_webgpu_device_cast(
    iree_hal_device_t* base_value) {
  IREE_HAL_ASSERT_TYPE(base_value, &iree_hal_webgpu_device_vtable);
  return (iree_hal_webgpu_device_t*)base_value;
}

IREE_API_EXPORT iree_status_t iree_hal_webgpu_wrap_device(
    iree_string_view_t identifier,
    const iree_hal_webgpu_device_options_t* options, WGPUDevice handle,
    iree_allocator_t host_allocator, iree_hal_device_t** out_device) {
  IREE_ASSERT_ARGUMENT(options);
  IREE_ASSERT_ARGUMENT(handle);
  IREE_ASSERT_ARGUMENT(out_device);
  IREE_TRACE_ZONE_BEGIN(z0);
  *out_device = NULL;

  WGPUSupportedLimits supported_limits;
  memset(&supported_limits, 0, sizeof(supported_limits));
  if (!wgpuDeviceGetLimits(handle, &supported_limits)) {
    // Failed to query limits - conservatively set what we need.
    // TODO(benvanik): see if it's realistic for this to fail - it cannot in
    // the browser implementation so I'm not sure why it returns bool here.
    supported_limits.limits.minStorageBufferOffsetAlignment = 256;
    supported_limits.limits.minUniformBufferOffsetAlignment = 256;
  }

  iree_hal_webgpu_device_t* device = NULL;
  iree_host_size_t total_size =
      sizeof(*device) + options->queue_uniform_buffer_size + identifier.size;
  IREE_RETURN_AND_END_ZONE_IF_ERROR(
      z0, iree_allocator_malloc(host_allocator, total_size, (void**)&device));
  iree_hal_resource_initialize(&iree_hal_webgpu_device_vtable,
                               &device->resource);
  device->host_allocator = host_allocator;
  uint8_t* buffer_ptr = (uint8_t*)device + sizeof(*device);
  buffer_ptr += options->queue_uniform_buffer_size;
  buffer_ptr += iree_string_view_append_to_buffer(
      identifier, &device->identifier, (char*)buffer_ptr);

  device->owns_device_handle = false;
  device->handle = handle;
  device->queue = wgpuDeviceGetQueue(handle);

  iree_arena_block_pool_initialize(IREE_HAL_WEBGPU_SMALL_POOL_BLOCK_SIZE,
                                   host_allocator, &device->small_block_pool);
  iree_arena_block_pool_initialize(IREE_HAL_WEBGPU_LARGE_POOL_BLOCK_SIZE,
                                   host_allocator, &device->large_block_pool);

  iree_hal_webgpu_bind_group_cache_initialize(device->handle,
                                              &device->bind_group_cache);

  iree_status_t status = iree_hal_webgpu_simple_allocator_create(
      (iree_hal_device_t*)device, device->identifier, device->host_allocator,
      &device->device_allocator);

  if (iree_status_is_ok(status)) {
    status = iree_hal_webgpu_staging_buffer_initialize(
        device->handle, &supported_limits.limits, device->device_allocator,
        device->staging_buffer_host_data, options->queue_uniform_buffer_size,
        &device->staging_buffer);
  }

  if (iree_status_is_ok(status)) {
    status = iree_hal_webgpu_builtins_initialize(
        device->handle, &device->staging_buffer, &device->builtins);
  }

  if (iree_status_is_ok(status)) {
    *out_device = (iree_hal_device_t*)device;
  } else {
    iree_hal_device_release((iree_hal_device_t*)device);
  }
  IREE_TRACE_ZONE_END(z0);
  return status;
}

static void iree_hal_webgpu_device_destroy(iree_hal_device_t* base_device) {
  iree_hal_webgpu_device_t* device = iree_hal_webgpu_device_cast(base_device);
  iree_allocator_t host_allocator = iree_hal_device_host_allocator(base_device);
  IREE_TRACE_ZONE_BEGIN(z0);

  // Builtins may be retaining resources; must be dropped first.
  iree_hal_webgpu_builtins_deinitialize(&device->builtins);

  // Bind groups can retain buffers.
  iree_hal_webgpu_bind_group_cache_deinitialize(&device->bind_group_cache);

  // There must be no more buffers live that use the allocator.
  iree_hal_webgpu_staging_buffer_deinitialize(&device->staging_buffer);
  iree_hal_allocator_release(device->device_allocator);

  // All outstanding blocks must have been returned to the pool (all command
  // buffers/submissions/etc disposed).
  iree_arena_block_pool_deinitialize(&device->small_block_pool);
  iree_arena_block_pool_deinitialize(&device->large_block_pool);

  // If we wrapped an existing device we don't want to destroy it on shutdown as
  // it may still be in use by the hosting application.
  if (device->owns_device_handle) {
    // NOTE: this destroys the device immediately (vs dropping it); that's fine
    // as we have the same requirement in the HAL.
    wgpuDeviceDestroy(device->handle);
  }

  iree_allocator_free(host_allocator, device);

  IREE_TRACE_ZONE_END(z0);
}

static iree_string_view_t iree_hal_webgpu_device_id(
    iree_hal_device_t* base_device) {
  iree_hal_webgpu_device_t* device = iree_hal_webgpu_device_cast(base_device);
  return device->identifier;
}

static iree_allocator_t iree_hal_webgpu_device_host_allocator(
    iree_hal_device_t* base_device) {
  iree_hal_webgpu_device_t* device = iree_hal_webgpu_device_cast(base_device);
  return device->host_allocator;
}

static iree_hal_allocator_t* iree_hal_webgpu_device_allocator(
    iree_hal_device_t* base_device) {
  iree_hal_webgpu_device_t* device = iree_hal_webgpu_device_cast(base_device);
  return device->device_allocator;
}

WGPUDevice iree_hal_webgpu_device_handle(iree_hal_device_t* base_device) {
  iree_hal_webgpu_device_t* device = iree_hal_webgpu_device_cast(base_device);
  return device->handle;
}

static iree_status_t iree_hal_webgpu_device_trim(
    iree_hal_device_t* base_device) {
  iree_hal_webgpu_device_t* device = iree_hal_webgpu_device_cast(base_device);
  iree_arena_block_pool_trim(&device->small_block_pool);
  iree_arena_block_pool_trim(&device->large_block_pool);
  return iree_hal_allocator_trim(device->device_allocator);
}

static iree_status_t iree_hal_webgpu_device_query_i64(
    iree_hal_device_t* base_device, iree_string_view_t category,
    iree_string_view_t key, int64_t* out_value) {
  // iree_hal_webgpu_device_t* device =
  // iree_hal_webgpu_device_cast(base_device);
  *out_value = 0;

  if (iree_string_view_equal(category,
                             iree_make_cstring_view("hal.executable.format"))) {
    *out_value =
        iree_string_view_equal(key, iree_make_cstring_view("webgpu-wgsl-fb"))
            ? 1
            : 0;
    return iree_ok_status();
  }

  return iree_make_status(
      IREE_STATUS_NOT_FOUND,
      "unknown device configuration key value '%.*s :: %.*s'",
      (int)category.size, category.data, (int)key.size, key.data);
}

static iree_status_t iree_hal_webgpu_device_create_command_buffer(
    iree_hal_device_t* base_device, iree_hal_command_buffer_mode_t mode,
    iree_hal_command_category_t command_categories,
    iree_hal_queue_affinity_t queue_affinity, iree_host_size_t binding_capacity,
    iree_hal_command_buffer_t** out_command_buffer) {
  iree_hal_webgpu_device_t* device = iree_hal_webgpu_device_cast(base_device);
  return iree_hal_webgpu_command_buffer_create(
      (iree_hal_device_t*)device, device->handle, mode, command_categories,
      queue_affinity, binding_capacity, &device->large_block_pool,
      &device->staging_buffer, &device->bind_group_cache, &device->builtins,
      device->host_allocator, out_command_buffer);
}

static iree_status_t iree_hal_webgpu_device_create_descriptor_set_layout(
    iree_hal_device_t* base_device,
    iree_hal_descriptor_set_layout_flags_t flags,
    iree_host_size_t binding_count,
    const iree_hal_descriptor_set_layout_binding_t* bindings,
    iree_hal_descriptor_set_layout_t** out_descriptor_set_layout) {
  iree_hal_webgpu_device_t* device = iree_hal_webgpu_device_cast(base_device);
  return iree_hal_webgpu_descriptor_set_layout_create(
      device->handle, flags, binding_count, bindings, device->host_allocator,
      out_descriptor_set_layout);
}

static iree_status_t iree_hal_webgpu_device_create_event(
    iree_hal_device_t* base_device, iree_hal_event_t** out_event) {
  iree_hal_webgpu_device_t* device = iree_hal_webgpu_device_cast(base_device);
  return iree_hal_webgpu_nop_event_create(device->host_allocator, out_event);
}

static iree_status_t iree_hal_webgpu_device_create_executable_cache(
    iree_hal_device_t* base_device, iree_string_view_t identifier,
    iree_loop_t loop, iree_hal_executable_cache_t** out_executable_cache) {
  iree_hal_webgpu_device_t* device = iree_hal_webgpu_device_cast(base_device);
  return iree_hal_webgpu_nop_executable_cache_create(
      device->handle, identifier, loop, device->host_allocator,
      out_executable_cache);
}

static iree_status_t iree_hal_webgpu_device_create_pipeline_layout(
    iree_hal_device_t* base_device, iree_host_size_t push_constants,
    iree_host_size_t set_layout_count,
    iree_hal_descriptor_set_layout_t* const* set_layouts,
    iree_hal_pipeline_layout_t** out_pipeline_layout) {
  iree_hal_webgpu_device_t* device = iree_hal_webgpu_device_cast(base_device);
  return iree_hal_webgpu_pipeline_layout_create(
      device->handle, set_layout_count, set_layouts, push_constants,
      &device->staging_buffer, device->host_allocator, out_pipeline_layout);
}

static iree_status_t iree_hal_webgpu_device_create_semaphore(
    iree_hal_device_t* base_device, uint64_t initial_value,
    iree_hal_semaphore_t** out_semaphore) {
  iree_hal_webgpu_device_t* device = iree_hal_webgpu_device_cast(base_device);
  return iree_hal_webgpu_nop_semaphore_create(
      initial_value, device->host_allocator, out_semaphore);
}

static iree_hal_semaphore_compatibility_t
iree_hal_webgpu_device_query_semaphore_compatibility(
    iree_hal_device_t* base_device, iree_hal_semaphore_t* semaphore) {
  // TODO(benvanik): implement webgpu semaphores.
  return IREE_HAL_SEMAPHORE_COMPATIBILITY_HOST_ONLY;
}

static iree_status_t iree_hal_webgpu_device_queue_alloca(
    iree_hal_device_t* base_device, iree_hal_queue_affinity_t queue_affinity,
    const iree_hal_semaphore_list_t wait_semaphore_list,
    const iree_hal_semaphore_list_t signal_semaphore_list,
    iree_hal_allocator_pool_t pool, iree_hal_buffer_params_t params,
    iree_device_size_t allocation_size,
    iree_hal_buffer_t** IREE_RESTRICT out_buffer) {
  // TODO(benvanik): queue-ordered allocations.
  IREE_RETURN_IF_ERROR(iree_hal_semaphore_list_wait(wait_semaphore_list,
                                                    iree_infinite_timeout()));
  IREE_RETURN_IF_ERROR(iree_hal_allocator_allocate_buffer(
      iree_hal_device_allocator(base_device), params, allocation_size,
      iree_const_byte_span_empty(), out_buffer));
  IREE_RETURN_IF_ERROR(iree_hal_semaphore_list_signal(signal_semaphore_list));
  return iree_ok_status();
}

static iree_status_t iree_hal_webgpu_device_queue_dealloca(
    iree_hal_device_t* base_device, iree_hal_queue_affinity_t queue_affinity,
    const iree_hal_semaphore_list_t wait_semaphore_list,
    const iree_hal_semaphore_list_t signal_semaphore_list,
    iree_hal_buffer_t* buffer) {
  // TODO(benvanik): queue-ordered allocations.
  IREE_RETURN_IF_ERROR(iree_hal_device_queue_barrier(
      base_device, queue_affinity, wait_semaphore_list, signal_semaphore_list));
  return iree_ok_status();
}

static iree_status_t iree_hal_webgpu_device_queue_execute(
    iree_hal_device_t* base_device, iree_hal_queue_affinity_t queue_affinity,
    const iree_hal_semaphore_list_t wait_semaphore_list,
    const iree_hal_semaphore_list_t signal_semaphore_list,
    iree_host_size_t command_buffer_count,
    iree_hal_command_buffer_t* const* command_buffers) {
  iree_hal_webgpu_device_t* device = iree_hal_webgpu_device_cast(base_device);

  // TODO(benvanik): this currently assumes we are synchronizing on semaphores
  // and that any passed in to wait on will already be signaled. This would need
  // to change a bit to properly support waiting on host-signaled semaphores.
  // All work is ordered against the WebGPU queues and there's only one queue so
  // there's really not much to do.
  IREE_RETURN_IF_ERROR(iree_hal_semaphore_list_wait(wait_semaphore_list,
                                                    iree_infinite_timeout()));

  // TODO(benvanik): propagate errors to semaphores.
  for (iree_host_size_t i = 0; i < command_buffer_count; i++) {
    iree_hal_command_buffer_t* command_buffer = command_buffers[i];
    IREE_RETURN_IF_ERROR(
        iree_hal_webgpu_command_buffer_issue(command_buffer, device->queue));
  }

  IREE_RETURN_IF_ERROR(iree_hal_semaphore_list_signal(signal_semaphore_list));

  return iree_ok_status();
}

static iree_status_t iree_hal_webgpu_device_queue_flush(
    iree_hal_device_t* base_device, iree_hal_queue_affinity_t queue_affinity) {
  // Currently unused; we flush as submissions are made.
  return iree_ok_status();
}

static iree_status_t iree_hal_webgpu_device_wait_semaphores(
    iree_hal_device_t* base_device, iree_hal_wait_mode_t wait_mode,
    const iree_hal_semaphore_list_t semaphore_list, iree_timeout_t timeout) {
  return iree_make_status(
      IREE_STATUS_UNIMPLEMENTED,
      "iree_hal_webgpu_device_wait_semaphores not yet implemented");
}

static iree_status_t iree_hal_webgpu_device_profiling_begin(
    iree_hal_device_t* device,
    const iree_hal_device_profiling_options_t* options) {
  // Unimplemented (and that's ok).
  return iree_ok_status();
}

static iree_status_t iree_hal_webgpu_device_profiling_end(
    iree_hal_device_t* device) {
  // Unimplemented (and that's ok).
  return iree_ok_status();
}

const iree_hal_device_vtable_t iree_hal_webgpu_device_vtable = {
    .destroy = iree_hal_webgpu_device_destroy,
    .id = iree_hal_webgpu_device_id,
    .host_allocator = iree_hal_webgpu_device_host_allocator,
    .device_allocator = iree_hal_webgpu_device_allocator,
    .trim = iree_hal_webgpu_device_trim,
    .query_i64 = iree_hal_webgpu_device_query_i64,
    .create_command_buffer = iree_hal_webgpu_device_create_command_buffer,
    .create_descriptor_set_layout =
        iree_hal_webgpu_device_create_descriptor_set_layout,
    .create_event = iree_hal_webgpu_device_create_event,
    .create_executable_cache = iree_hal_webgpu_device_create_executable_cache,
    .create_pipeline_layout = iree_hal_webgpu_device_create_pipeline_layout,
    .create_semaphore = iree_hal_webgpu_device_create_semaphore,
    .query_semaphore_compatibility =
        iree_hal_webgpu_device_query_semaphore_compatibility,
    .transfer_range = iree_hal_device_submit_transfer_range_and_wait,
    .queue_alloca = iree_hal_webgpu_device_queue_alloca,
    .queue_dealloca = iree_hal_webgpu_device_queue_dealloca,
    .queue_execute = iree_hal_webgpu_device_queue_execute,
    .queue_flush = iree_hal_webgpu_device_queue_flush,
    .wait_semaphores = iree_hal_webgpu_device_wait_semaphores,
    .profiling_begin = iree_hal_webgpu_device_profiling_begin,
    .profiling_end = iree_hal_webgpu_device_profiling_end,
};