//
// File:       fft_setup.cpp
//
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#include "fft_base_kernels.h"
#include "fft_internal.h"
#include <cstdlib>
#include <cstring>
#include <iostream>
#include <limits>
#include <sstream>
#include <string>
#include <sys/stat.h>
#include <sys/types.h>

using namespace std;

extern void getKernelWorkDimensions(cl_fft_plan *plan, cl_fft_kernel_info *kernelInfo, cl_int *batchSize, size_t *gWorkItems, size_t *lWorkItems);

static void
getBlockConfigAndKernelString(cl_fft_plan *plan)
{
    plan->temp_buffer_needed = 0;
    *plan->kernel_string += baseKernels;

    if (plan->format == clFFT_SplitComplexFormat)
        *plan->kernel_string += twistKernelPlannar;
    else
        *plan->kernel_string += twistKernelInterleaved;

    switch (plan->dim)
        {
        case clFFT_1D:
            FFT1D(plan, cl_fft_kernel_x);
            break;

        case clFFT_2D:
            FFT1D(plan, cl_fft_kernel_x);
            FFT1D(plan, cl_fft_kernel_y);
            break;

        case clFFT_3D:
            FFT1D(plan, cl_fft_kernel_x);
            FFT1D(plan, cl_fft_kernel_y);
            FFT1D(plan, cl_fft_kernel_z);
            break;

        default:
            return;
        }

    plan->temp_buffer_needed = 0;
    cl_fft_kernel_info *kInfo = plan->kernel_info;
    while (kInfo)
        {
            plan->temp_buffer_needed |= !kInfo->in_place_possible;
            kInfo = kInfo->next;
        }
}


static void
deleteKernelInfo(cl_fft_kernel_info *kInfo)
{
    if (kInfo)
        {
            if (kInfo->kernel_name)
                free(kInfo->kernel_name);
            if (kInfo->kernel)
                clReleaseKernel(kInfo->kernel);
            free(kInfo);
        }
}

static void
destroy_plan(cl_fft_plan *Plan)
{
    cl_fft_kernel_info *kernel_info = Plan->kernel_info;

    while (kernel_info)
        {
            cl_fft_kernel_info *tmp = kernel_info->next;
            deleteKernelInfo(kernel_info);
            kernel_info = tmp;
        }

    Plan->kernel_info = nullptr;

    if (Plan->kernel_string)
        {
            delete Plan->kernel_string;
            Plan->kernel_string = nullptr;
        }
    if (Plan->twist_kernel)
        {
            clReleaseKernel(Plan->twist_kernel);
            Plan->twist_kernel = nullptr;
        }
    if (Plan->program)
        {
            clReleaseProgram(Plan->program);
            Plan->program = nullptr;
        }
    if (Plan->tempmemobj)
        {
            clReleaseMemObject(Plan->tempmemobj);
            Plan->tempmemobj = nullptr;
        }
    if (Plan->tempmemobj_real)
        {
            clReleaseMemObject(Plan->tempmemobj_real);
            Plan->tempmemobj_real = nullptr;
        }
    if (Plan->tempmemobj_imag)
        {
            clReleaseMemObject(Plan->tempmemobj_imag);
            Plan->tempmemobj_imag = nullptr;
        }
}

static int
createKernelList(cl_fft_plan *plan)
{
    cl_program program = plan->program;
    cl_fft_kernel_info *kernel_info = plan->kernel_info;

    cl_int err;
    while (kernel_info)
        {
            kernel_info->kernel = clCreateKernel(program, kernel_info->kernel_name, &err);
            if (!kernel_info->kernel || err != CL_SUCCESS)
                return err;
            kernel_info = kernel_info->next;
        }

    if (plan->format == clFFT_SplitComplexFormat)
        plan->twist_kernel = clCreateKernel(program, "clFFT_1DTwistSplit", &err);
    else
        plan->twist_kernel = clCreateKernel(program, "clFFT_1DTwistInterleaved", &err);

    if (!plan->twist_kernel || err)
        return err;

    return CL_SUCCESS;
}

int getMaxKernelWorkGroupSize(cl_fft_plan *plan, unsigned int *max_wg_size, unsigned int num_devices, cl_device_id *devices)
{
    int reg_needed = 0;
    *max_wg_size = std::numeric_limits<int>::max();
    int err;
    unsigned wg_size;

    unsigned int i;
    for (i = 0; i < num_devices; i++)
        {
            cl_fft_kernel_info *kInfo = plan->kernel_info;
            while (kInfo)
                {
                    err = clGetKernelWorkGroupInfo(kInfo->kernel, devices[i], CL_KERNEL_WORK_GROUP_SIZE, sizeof(size_t), &wg_size, nullptr);
                    if (err != CL_SUCCESS)
                        return -1;

                    if (wg_size < kInfo->num_workitems_per_workgroup)
                        reg_needed |= 1;

                    if (*max_wg_size > wg_size)
                        *max_wg_size = wg_size;

                    kInfo = kInfo->next;
                }
        }

    return reg_needed;
}

#define ERR_MACRO(err)                               \
    {                                                \
        if (err != CL_SUCCESS)                       \
            {                                        \
                if (error_code)                      \
                    *error_code = err;               \
                clFFT_DestroyPlan((clFFT_Plan)plan); \
                return (clFFT_Plan)NULL;             \
            }                                        \
    }

clFFT_Plan
clFFT_CreatePlan(cl_context context, clFFT_Dim3 n, clFFT_Dimension dim, clFFT_DataFormat dataFormat, cl_int *error_code)
{
    int i;
    cl_int err;
    int isPow2 = 1;
    cl_fft_plan *plan = nullptr;
    ostringstream kString;
    int num_devices;
    int gpu_found = 0;
    cl_device_id devices[16];
    size_t ret_size;
    cl_device_type device_type;

    if (!context)
        ERR_MACRO(CL_INVALID_VALUE);

    isPow2 |= n.x && !((n.x - 1) & n.x);
    isPow2 |= n.y && !((n.y - 1) & n.y);
    isPow2 |= n.z && !((n.z - 1) & n.z);

    if (!isPow2)
        ERR_MACRO(CL_INVALID_VALUE);

    if ((dim == clFFT_1D && (n.y != 1 || n.z != 1)) || (dim == clFFT_2D && n.z != 1))
        ERR_MACRO(CL_INVALID_VALUE);

    plan = (cl_fft_plan *)malloc(sizeof(cl_fft_plan));
    if (!plan)
        ERR_MACRO(CL_OUT_OF_RESOURCES);

    plan->context = context;
    clRetainContext(context);
    plan->n = n;
    plan->dim = dim;
    plan->format = dataFormat;
    plan->kernel_info = nullptr;
    plan->num_kernels = 0;
    plan->twist_kernel = nullptr;
    plan->program = nullptr;
    plan->temp_buffer_needed = 0;
    plan->last_batch_size = 0;
    plan->tempmemobj = nullptr;
    plan->tempmemobj_real = nullptr;
    plan->tempmemobj_imag = nullptr;
    plan->max_localmem_fft_size = 2048;
    plan->max_work_item_per_workgroup = 256;
    plan->max_radix = 16;
    plan->min_mem_coalesce_width = 16;
    plan->num_local_mem_banks = 16;

patch_kernel_source:

    plan->kernel_string = new string("");
    if (!plan->kernel_string)
        ERR_MACRO(CL_OUT_OF_RESOURCES);

    getBlockConfigAndKernelString(plan);

    const char *source_str = plan->kernel_string->c_str();
    plan->program = clCreateProgramWithSource(context, 1, (const char **)&source_str, nullptr, &err);
    ERR_MACRO(err);

    err = clGetContextInfo(context, CL_CONTEXT_DEVICES, sizeof(devices), devices, &ret_size);
    ERR_MACRO(err);

    num_devices = (int)(ret_size / sizeof(cl_device_id));

    for (i = 0; i < num_devices; i++)
        {
            err = clGetDeviceInfo(devices[i], CL_DEVICE_TYPE, sizeof(device_type), &device_type, nullptr);
            ERR_MACRO(err);

            if (device_type == CL_DEVICE_TYPE_GPU)
                {
                    gpu_found = 1;
                    err = clBuildProgram(plan->program, 1, &devices[i], "-cl-mad-enable", nullptr, nullptr);
                    if (err != CL_SUCCESS)
                        {
                            char *build_log;
                            char devicename[200];
                            size_t log_size;

                            err = clGetProgramBuildInfo(plan->program, devices[i], CL_PROGRAM_BUILD_LOG, 0, nullptr, &log_size);
                            ERR_MACRO(err);

                            build_log = (char *)malloc(log_size + 1);

                            err = clGetProgramBuildInfo(plan->program, devices[i], CL_PROGRAM_BUILD_LOG, log_size, build_log, nullptr);
                            ERR_MACRO(err);

                            err = clGetDeviceInfo(devices[i], CL_DEVICE_NAME, sizeof(devicename), devicename, nullptr);
                            ERR_MACRO(err);

                            fprintf(stdout, "FFT program build log on device %s\n", devicename);
                            fprintf(stdout, "%s\n", build_log);
                            free(build_log);

                            ERR_MACRO(err);
                        }
                }
        }

    if (!gpu_found)
        ERR_MACRO(CL_INVALID_CONTEXT);

    err = createKernelList(plan);
    ERR_MACRO(err);

    // we created program and kernels based on "some max work group size (default 256)" ... this work group size
    // may be larger than what kernel may execute with ... if thats the case we need to regenerate the kernel source
    // setting this as limit i.e max group size and rebuild.
    unsigned int max_kernel_wg_size;
    int patching_req = getMaxKernelWorkGroupSize(plan, &max_kernel_wg_size, num_devices, devices);
    if (patching_req == -1)
        {
            ERR_MACRO(err);
        }

    if (patching_req)
        {
            destroy_plan(plan);
            plan->max_work_item_per_workgroup = max_kernel_wg_size;
            goto patch_kernel_source;
        }

    cl_fft_kernel_info *kInfo = plan->kernel_info;
    while (kInfo)
        {
            plan->num_kernels++;
            kInfo = kInfo->next;
        }

    if (error_code)
        *error_code = CL_SUCCESS;

    return (clFFT_Plan)plan;
}

void clFFT_DestroyPlan(clFFT_Plan plan)
{
    auto *Plan = (cl_fft_plan *)plan;
    if (Plan)
        {
            destroy_plan(Plan);
            clReleaseContext(Plan->context);
            free(Plan);
        }
}

void clFFT_DumpPlan(clFFT_Plan Plan, FILE *file)
{
    size_t gDim, lDim;
    FILE *out;
    if (!file)
        out = stdout;
    else
        out = file;

    auto *plan = (cl_fft_plan *)Plan;
    cl_fft_kernel_info *kInfo = plan->kernel_info;

    while (kInfo)
        {
            cl_int s = 1;
            getKernelWorkDimensions(plan, kInfo, &s, &gDim, &lDim);
            fprintf(out, "Run kernel %s with global dim = {%zd*BatchSize}, local dim={%zd}\n", kInfo->kernel_name, gDim, lDim);
            kInfo = kInfo->next;
        }
    fprintf(out, "%s\n", plan->kernel_string->c_str());
}