#include "ggml-opencl.h"

#include <array>
#include <atomic>
#include <sstream>

#define CL_TARGET_OPENCL_VERSION 110
#include <clblast.h>

#include <stdlib.h>
#include <stdio.h>
#include <string.h>

#include "ggml.h"

#define CL_DMMV_BLOCK_SIZE 32;

#define MULTILINE_QUOTE(...) #__VA_ARGS__
static std::string program_source = MULTILINE_QUOTE(

typedef char int8_t;
typedef uchar uint8_t;
typedef int int32_t;
typedef uint uint32_t;

struct __attribute__ ((packed)) block_q4_0
{
    half d;
    uint8_t qs[QK4_0 / 2];
};

struct __attribute__ ((packed)) block_q4_1
{
    half d;
    half m;
    uint8_t qs[QK4_1 / 2];
};

struct __attribute__ ((packed)) block_q5_0
{
    half d;
    uint32_t qh;
    uint8_t qs[QK5_0 / 2];
};

struct __attribute__ ((packed)) block_q5_1
{
    half d;
    half m;
    uint32_t qh;
    uint8_t qs[QK5_1 / 2];
};

struct __attribute__ ((packed)) block_q8_0
{
    half d;
    int8_t qs[QK8_0];
};


__kernel void convert_fp16_to_fp32(__global half* x, __global float* y) {
    const uint i = get_global_id(0);

    y[i] = vload_half(0, &x[i]);
}

void dequantize_q4_0(__global const struct block_q4_0* x, const int ib, const int iqs, float* v0, float* v1) {
    const float d = vload_half(0, &x[ib].d);

    const uint8_t vui = x[ib].qs[iqs];

    const int8_t vi0 = vui & 0xF;
    const int8_t vi1 = vui >> 4;

    *v0 = (vi0 - 8)*d;
    *v1 = (vi1 - 8)*d;
}
void dequantize_q4_1(__global const struct block_q4_1* x, const int ib, const int iqs, float* v0, float* v1) {
    const float d = vload_half(0, &x[ib].d);
    const float m = vload_half(0, &x[ib].m);

    const uint8_t vui = x[ib].qs[iqs];

    const int8_t vi0 = vui & 0xF;
    const int8_t vi1 = vui >> 4;

    *v0 = vi0*d + m;
    *v1 = vi1*d + m;
}
void dequantize_q5_0(__global const struct block_q5_0* x, const int ib, const int iqs, float* v0, float* v1) {
    const float d = vload_half(0, &x[ib].d);

    uint32_t qh = x[ib].qh;

    const uint8_t xh_0 = ((qh >> (iqs +  0)) << 4) & 0x10;
    const uint8_t xh_1 = ((qh >> (iqs + 12))     ) & 0x10;

    const int32_t x0 = ((x[ib].qs[iqs] & 0xf) | xh_0) - 16;
    const int32_t x1 = ((x[ib].qs[iqs] >>  4) | xh_1) - 16;

    *v0 = x0*d;
    *v1 = x1*d;
}
void dequantize_q5_1(__global const struct block_q5_1* x, const int ib, const int iqs, float* v0, float* v1) {
    const float d = vload_half(0, &x[ib].d);
    const float m = vload_half(0, &x[ib].m);

    uint32_t qh = x[ib].qh;

    const uint8_t xh_0 = ((qh >> (iqs +  0)) << 4) & 0x10;
    const uint8_t xh_1 = ((qh >> (iqs + 12))     ) & 0x10;

    const int32_t x0 = ((x[ib].qs[iqs] & 0xf) | xh_0);
    const int32_t x1 = ((x[ib].qs[iqs] >>  4) | xh_1);

    *v0 = x0*d + m;
    *v1 = x1*d + m;
}
void dequantize_q8_0(__global const struct block_q8_0* x, const int ib, const int iqs, float* v0, float* v1) {
    const float d = vload_half(0, &x[ib].d);

    const int8_t vi0 = x[ib].qs[iqs + 0];
    const int8_t vi1 = x[ib].qs[iqs + 1];

    *v0 = vi0*d;
    *v1 = vi1*d;
}
void convert_f16(__global half* x, const int ib, const int iqs, float* v0, float* v1){
    *v0 = vload_half(0, &x[ib + 0]);
    *v1 = vload_half(0, &x[ib + 1]);
}
);

std::string dequant_template = MULTILINE_QUOTE(
__kernel void KERNEL_NAME(__global X_TYPE* x, __global float* y) {
    const int i = get_group_id(0)*get_local_size(0) + get_local_id(0)*2;

    if (i >= get_global_size(0)) {
        return;
    }

    const uint qk = QUANT_K;
    const uint qr = QUANT_R;

    const int ib = i/qk; // block index
    const int iqs = (i%qk)/qr; // quant index
    const int iybs = i - i%qk; // y block start index
    const int y_offset = qr == 1 ? 1 : qk/2;

    // dequantize
    float v0, v1;
    DEQUANT_FUNC(x, ib, iqs, &v0, &v1);
    y[iybs + iqs + 0] = v0;
    y[iybs + iqs + y_offset] = v1;
}
);

std::string dequant_mul_mat_vec_template = MULTILINE_QUOTE(
__kernel void KERNEL_NAME(__global X_TYPE* x, __local float* tmp, __global float* y, __global float* dst, const int ncols) {
    const int block_size = get_local_size(0);
    const int row = get_global_id(0) / block_size;
    const int tid = get_local_id(0);

    const uint qk = QUANT_K;
    const uint qr = QUANT_R;

    const int y_offset = qr == 1 ? 1 : qk/2;

    tmp[tid] = 0;

    for (int i = 0; i < ncols/block_size; i += 2) {
        const int col = i*block_size + 2*tid;
        const int ib = (row*ncols + col)/qk; // block index
        const int iqs = (col%qk)/qr; // quant index
        const int iybs = col - col%qk; // y block start index

        // dequantize
        float v0, v1;
        DEQUANT_FUNC(x, ib, iqs, &v0, &v1);

        // matrix multiplication
        tmp[tid] += v0 * y[iybs + iqs + 0];
        tmp[tid] += v1 * y[iybs + iqs + y_offset];
    }

    // sum up partial sums and write back result
    barrier(CLK_LOCAL_MEM_FENCE);
    for (int s=block_size/2; s>0; s>>=1) {
        if (tid < s) {
            tmp[tid] += tmp[tid + s];
        }
        barrier(CLK_LOCAL_MEM_FENCE);
    }
    if (tid == 0) {
        dst[row] = tmp[0];
    }
}
);

#define CL_CHECK(err)                                               \
    do {                                                            \
        cl_int err_ = (err);                                        \
        if (err_ != CL_SUCCESS) {                                   \
            fprintf(stderr, "ggml_opencl: %s error %d at %s:%d\n",  \
                #err, err_, __FILE__, __LINE__);                    \
            exit(1);                                                \
        }                                                           \
    } while (0)

#define CLBLAST_CHECK(err)                                          \
    do {                                                            \
        CLBlastStatusCode err_ = (err);                             \
        if (err_ != CLBlastSuccess) {                               \
            fprintf(stderr, "ggml_opencl: %s error %d at %s:%d\n",  \
                #err, err_, __FILE__, __LINE__);                    \
            exit(1);                                                \
        }                                                           \
    } while (0)

std::array<std::string, 5> dequant_str_keys = {
    "KERNEL_NAME", "X_TYPE", "QUANT_K", "QUANT_R", "DEQUANT_FUNC"
};

std::array<std::string, 30> dequant_str_values = {
    "dequantize_row_q4_0", "struct block_q4_0", "QK4_0", "QR4_0", "dequantize_q4_0",
    "dequantize_row_q4_1", "struct block_q4_1", "QK4_1", "QR4_1", "dequantize_q4_1",
    "dequantize_row_q5_0", "struct block_q5_0", "QK5_0", "QR5_0", "dequantize_q5_0",
    "dequantize_row_q5_1", "struct block_q5_1", "QK5_1", "QR5_1", "dequantize_q5_1",
    "dequantize_row_q8_0", "struct block_q8_0", "QK8_0", "QR8_0", "dequantize_q8_0",
    "convert_row_f16", "half", "1", "1", "convert_f16"
};

std::array<std::string, 30> dequant_mul_mat_vec_str_values = {
    "dequantize_mul_mat_vec_q4_0", "struct block_q4_0", "QK4_0", "QR4_0", "dequantize_q4_0",
    "dequantize_mul_mat_vec_q4_1", "struct block_q4_1", "QK4_1", "QR4_1", "dequantize_q4_1",
    "dequantize_mul_mat_vec_q5_0", "struct block_q5_0", "QK5_0", "QR5_0", "dequantize_q5_0",
    "dequantize_mul_mat_vec_q5_1", "struct block_q5_1", "QK5_1", "QR5_1", "dequantize_q5_1",
    "dequantize_mul_mat_vec_q8_0", "struct block_q8_0", "QK8_0", "QR8_0", "dequantize_q8_0",
    "convert_mul_mat_vec_f16", "half", "1", "1", "convert_f16"
};

std::string& replace(std::string& s, const std::string& from, const std::string& to) {
    size_t pos = 0;
    while ((pos = s.find(from, pos)) != std::string::npos) {
         s.replace(pos, from.length(), to);
         pos += to.length();
    }
    return s;
}

std::string generate_kernels() {
    std::stringstream src;
    src << program_source << '\n';
    for (size_t i = 0; i < dequant_str_values.size(); i += dequant_str_keys.size()) {
        std::string dequant_kernel = dequant_template;
        std::string dmmv_kernel = dequant_mul_mat_vec_template;
        for (size_t j = 0; j < dequant_str_keys.size(); j++) {
            replace(dequant_kernel, dequant_str_keys[j], dequant_str_values[i + j]);
            replace(dmmv_kernel, dequant_str_keys[j], dequant_mul_mat_vec_str_values[i + j]);
        }
        src << dequant_kernel << '\n';
        src << dmmv_kernel << '\n';
    }
    return src.str();
}

static cl_platform_id platform;
static cl_device_id device;
static cl_context context;
static cl_command_queue queue;
static cl_program program;
static cl_kernel convert_row_f16_cl;
static cl_kernel dequantize_row_q4_0_cl, dequantize_row_q4_1_cl, dequantize_row_q5_0_cl, dequantize_row_q5_1_cl, dequantize_row_q8_0_cl;
static cl_kernel dequantize_mul_mat_vec_q4_0_cl, dequantize_mul_mat_vec_q4_1_cl, dequantize_mul_mat_vec_q5_0_cl, dequantize_mul_mat_vec_q5_1_cl, dequantize_mul_mat_vec_q8_0_cl, convert_mul_mat_vec_f16_cl;
static bool fp16_support;

static cl_program build_program_from_source(cl_context ctx, cl_device_id dev, const char* program_buffer) {
    cl_program p;
    char *program_log;
    size_t program_size;
    size_t log_size;
    int err;

    program_size = strlen(program_buffer);

    p = clCreateProgramWithSource(ctx, 1, (const char**)&program_buffer, &program_size, &err);
    if(err < 0) {
        fprintf(stderr, "OpenCL error creating program");
        exit(1);
    }

    const char* compile_opts = "-cl-mad-enable -cl-unsafe-math-optimizations -cl-finite-math-only -cl-fast-relaxed-math "
                               "-DQK4_0=32 -DQR4_0=2 -DQK4_1=32 -DQR4_1=2 -DQK5_0=32 -DQR5_0=2 -DQK5_1=32 -DQR5_1=2 -DQK8_0=32 -DQR8_0=1";

    err = clBuildProgram(p, 0, NULL, compile_opts, NULL, NULL);
    if(err < 0) {

        clGetProgramBuildInfo(p, dev, CL_PROGRAM_BUILD_LOG, 0, NULL, &log_size);
        program_log = (char*) malloc(log_size + 1);
        program_log[log_size] = '\0';
        clGetProgramBuildInfo(p, dev, CL_PROGRAM_BUILD_LOG, log_size + 1, program_log, NULL);
        fprintf(stderr, "ggml_opencl: kernel compile error:\n\n%s\n", program_log);
        free(program_log);
        exit(1);
    }

    return p;
}

void ggml_cl_init(void) {
    cl_int err;

    struct cl_device;
    struct cl_platform {
        cl_platform_id id;
        unsigned number;
        char name[128];
        char vendor[128];
        struct cl_device * devices;
        unsigned n_devices;
        struct cl_device * default_device;
    };

    struct cl_device {
        struct cl_platform * platform;
        cl_device_id id;
        unsigned number;
        cl_device_type type;
        char name[128];
    };

    enum { NPLAT = 16, NDEV = 16 };

    struct cl_platform platforms[NPLAT];
    unsigned n_platforms = 0;
    struct cl_device devices[NDEV];
    unsigned n_devices = 0;
    struct cl_device * default_device = NULL;

    platform = NULL;
    device = NULL;

    cl_platform_id platform_ids[NPLAT];
    CL_CHECK(clGetPlatformIDs(NPLAT, platform_ids, &n_platforms));

    for (unsigned i = 0; i < n_platforms; i++) {
        struct cl_platform * p = &platforms[i];
        p->number = i;
        p->id = platform_ids[i];
        CL_CHECK(clGetPlatformInfo(p->id, CL_PLATFORM_NAME, sizeof(p->name), &p->name, NULL));
        CL_CHECK(clGetPlatformInfo(p->id, CL_PLATFORM_VENDOR, sizeof(p->vendor), &p->vendor, NULL));

        cl_device_id device_ids[NDEV];
        cl_int clGetDeviceIDsError = clGetDeviceIDs(p->id, CL_DEVICE_TYPE_ALL, NDEV, device_ids, &p->n_devices);
        if (clGetDeviceIDsError == CL_DEVICE_NOT_FOUND) {
            p->n_devices = 0;
        } else {
            CL_CHECK(clGetDeviceIDsError);
        }
        p->devices = p->n_devices > 0 ? &devices[n_devices] : NULL;
        p->default_device = NULL;

        for (unsigned j = 0; j < p->n_devices; j++) {
            struct cl_device * d = &devices[n_devices];
            d->number = n_devices++;
            d->id = device_ids[j];
            d->platform = p;
            CL_CHECK(clGetDeviceInfo(d->id, CL_DEVICE_NAME, sizeof(d->name), &d->name, NULL));
            CL_CHECK(clGetDeviceInfo(d->id, CL_DEVICE_TYPE, sizeof(d->type), &d->type, NULL));

            if (p->default_device == NULL && d->type == CL_DEVICE_TYPE_GPU) {
                p->default_device = d;
            }
        }

        if (default_device == NULL && p->default_device != NULL) {
            default_device = p->default_device;
        }
    }

    if (n_devices == 0) {
        fprintf(stderr, "ggml_opencl: could find any OpenCL devices.\n");
        exit(1);
    }

    char * user_platform_string = getenv("GGML_OPENCL_PLATFORM");
    char * user_device_string = getenv("GGML_OPENCL_DEVICE");
    int user_platform_number = -1;
    int user_device_number = -1;

    unsigned n;
    if (user_platform_string != NULL && sscanf(user_platform_string, " %u", &n) == 1 && n < n_platforms) {
        user_platform_number = (int)n;
    }
    if (user_device_string != NULL && sscanf(user_device_string, " %u", &n) == 1 && n < n_devices) {
        user_device_number = (int)n;
    }
    if (user_platform_number != -1 && user_device_number != -1) {
        cl_platform* platform = &platforms[user_platform_number];
        if ((unsigned)user_device_number >= platform->n_devices) {
            fprintf(stderr, "ggml_opencl: invalid device number %d\n", user_device_number);
            exit(1);
        }
        default_device = &platform->devices[user_device_number];
    } else {

        struct cl_device * selected_devices = devices;
        unsigned n_selected_devices = n_devices;

        if (user_platform_number == -1 && user_platform_string != NULL && user_platform_string[0] != 0) {
            for (unsigned i = 0; i < n_platforms; i++) {
                struct cl_platform * p = &platforms[i];
                if (strstr(p->name, user_platform_string) != NULL ||
                    strstr(p->vendor, user_platform_string) != NULL) {
                    user_platform_number = (int)i;
                    break;
                }
            }
            if (user_platform_number == -1) {
                fprintf(stderr, "ggml_opencl: no platform matching '%s' was found.\n", user_platform_string);
                exit(1);
            }
        }
        if (user_platform_number != -1) {
            struct cl_platform * p = &platforms[user_platform_number];
            selected_devices = p->devices;
            n_selected_devices = p->n_devices;
            default_device = p->default_device;
            if (n_selected_devices == 0) {
                fprintf(stderr, "ggml_opencl: selected platform '%s' does not have any devices.\n", p->name);
                exit(1);
            }
        }

        if (user_device_number == -1 && user_device_string != NULL && user_device_string[0] != 0) {
            for (unsigned i = 0; i < n_selected_devices; i++) {
                struct cl_device * d = &selected_devices[i];
                if (strstr(d->name, user_device_string) != NULL) {
                    user_device_number = d->number;
                    break;
                }
            }
            if (user_device_number == -1) {
                fprintf(stderr, "ggml_opencl: no device matching '%s' was found.\n", user_device_string);
                exit(1);
            }
        }
        if (user_device_number != -1) {
            selected_devices = &devices[user_device_number];
            n_selected_devices = 1;
            default_device = &selected_devices[0];
        }

        GGML_ASSERT(n_selected_devices > 0);

        if (default_device == NULL) {
            default_device = &selected_devices[0];
        }
    }

    fprintf(stderr, "ggml_opencl: selecting platform: '%s'\n", default_device->platform->name);
    fprintf(stderr, "ggml_opencl: selecting device: '%s'\n", default_device->name);
    if (default_device->type != CL_DEVICE_TYPE_GPU) {
        fprintf(stderr, "ggml_opencl: warning, not a GPU: '%s'.\n", default_device->name);
    }

    platform = default_device->platform->id;
    device = default_device->id;

    size_t ext_str_size;
    clGetDeviceInfo(device, CL_DEVICE_EXTENSIONS, 0, NULL, &ext_str_size);
    char* ext_buffer = (char*) malloc(sizeof(char) * ext_str_size);
    clGetDeviceInfo(device, CL_DEVICE_EXTENSIONS, ext_str_size, ext_buffer, NULL);
    // Check if ext_buffer contains cl_khr_fp16
    for (size_t i = 0; i < ext_str_size - 12; i++) {
        if (memcmp(ext_buffer + i, "cl_khr_fp16", 11) == 0) {
            fp16_support = true;
            break;
        }
    }
    free(ext_buffer);
    fprintf(stderr, "ggml_opencl: device FP16 support: %s\n", fp16_support ? "true" : "false");

    cl_context_properties properties[] = {
        (intptr_t)CL_CONTEXT_PLATFORM, (intptr_t)platform, 0
    };

    CL_CHECK((context = clCreateContext(properties, 1, &device, NULL, NULL, &err), err));

    CL_CHECK((queue = clCreateCommandQueue(context, device, CL_QUEUE_OUT_OF_ORDER_EXEC_MODE_ENABLE, &err),
        (err != CL_INVALID_QUEUE_PROPERTIES && err != CL_INVALID_VALUE ? err :
        (queue = clCreateCommandQueue(context, device, 0, &err), err)
    )));

    const std::string kernel_src = generate_kernels();

    program = build_program_from_source(context, device, kernel_src.c_str());

    // FP16 to FP32 kernel
    CL_CHECK((convert_row_f16_cl = clCreateKernel(program, "convert_row_f16", &err), err));

    // Dequantize kernels
    CL_CHECK((dequantize_row_q4_0_cl = clCreateKernel(program, "dequantize_row_q4_0", &err), err));
    CL_CHECK((dequantize_row_q4_1_cl = clCreateKernel(program, "dequantize_row_q4_1", &err), err));
    CL_CHECK((dequantize_row_q5_0_cl = clCreateKernel(program, "dequantize_row_q5_0", &err), err));
    CL_CHECK((dequantize_row_q5_1_cl = clCreateKernel(program, "dequantize_row_q5_1", &err), err));
    CL_CHECK((dequantize_row_q8_0_cl = clCreateKernel(program, "dequantize_row_q8_0", &err), err));

    // dequant mul mat kernel
    CL_CHECK((dequantize_mul_mat_vec_q4_0_cl = clCreateKernel(program, "dequantize_mul_mat_vec_q4_0", &err), err));
    CL_CHECK((dequantize_mul_mat_vec_q4_1_cl = clCreateKernel(program, "dequantize_mul_mat_vec_q4_1", &err), err));
    CL_CHECK((dequantize_mul_mat_vec_q5_0_cl = clCreateKernel(program, "dequantize_mul_mat_vec_q5_0", &err), err));
    CL_CHECK((dequantize_mul_mat_vec_q5_1_cl = clCreateKernel(program, "dequantize_mul_mat_vec_q5_1", &err), err));
    CL_CHECK((dequantize_mul_mat_vec_q8_0_cl = clCreateKernel(program, "dequantize_mul_mat_vec_q8_0", &err), err));
    CL_CHECK((convert_mul_mat_vec_f16_cl = clCreateKernel(program, "convert_mul_mat_vec_f16", &err), err));
}

static cl_kernel* ggml_get_to_fp32_cl(ggml_type type) {
    switch (type) {
        case GGML_TYPE_Q4_0:
            return &dequantize_row_q4_0_cl;
        case GGML_TYPE_Q4_1:
            return &dequantize_row_q4_1_cl;
        case GGML_TYPE_Q5_0:
            return &dequantize_row_q5_0_cl;
        case GGML_TYPE_Q5_1:
            return &dequantize_row_q5_1_cl;
        case GGML_TYPE_Q8_0:
            return &dequantize_row_q8_0_cl;
        case GGML_TYPE_F16:
            return &convert_row_f16_cl;
        default:
            return nullptr;
    }
}

static cl_kernel* ggml_get_dequantize_mul_mat_vec_cl(ggml_type type) {
    switch (type) {
        case GGML_TYPE_Q4_0:
            return &dequantize_mul_mat_vec_q4_0_cl;
        case GGML_TYPE_Q4_1:
            return &dequantize_mul_mat_vec_q4_1_cl;
        case GGML_TYPE_Q5_0:
            return &dequantize_mul_mat_vec_q5_0_cl;
        case GGML_TYPE_Q5_1:
            return &dequantize_mul_mat_vec_q5_1_cl;
        case GGML_TYPE_Q8_0:
            return &dequantize_mul_mat_vec_q8_0_cl;
        case GGML_TYPE_F16:
            return &convert_mul_mat_vec_f16_cl;
        default:
            return nullptr;
    }
}

// buffer pool for cl
#define MAX_CL_BUFFERS 256

struct scoped_spin_lock {
    std::atomic_flag& lock;
    scoped_spin_lock(std::atomic_flag& lock) : lock(lock) {
        while (lock.test_and_set(std::memory_order_acquire)) {
            ; // spin
        }
    }
    ~scoped_spin_lock() {
        lock.clear(std::memory_order_release);
    }
    scoped_spin_lock(const scoped_spin_lock&) = delete;
    scoped_spin_lock& operator=(const scoped_spin_lock&) = delete;
};

struct cl_buffer {
    cl_mem mem;
    size_t size = 0;
};

static cl_buffer g_cl_buffer_pool[MAX_CL_BUFFERS];
static std::atomic_flag g_cl_pool_lock = ATOMIC_FLAG_INIT;

static cl_mem ggml_cl_pool_malloc(size_t size, size_t * actual_size, cl_mem_flags flags) {
    scoped_spin_lock lock(g_cl_pool_lock);
    cl_int err;

    for (int i = 0; i < MAX_CL_BUFFERS; ++i) {
        cl_buffer& b = g_cl_buffer_pool[i];
        if (b.size > 0 && b.size >= size) {
            cl_mem mem = b.mem;
            *actual_size = b.size;
            b.size = 0;
            return mem;
        }
    }
    cl_mem mem;
    CL_CHECK((mem = clCreateBuffer(context, flags, size, NULL, &err), err));
    *actual_size = size;
    return mem;
}

static void ggml_cl_pool_free(cl_mem mem, size_t size) {
    scoped_spin_lock lock(g_cl_pool_lock);

    for (int i = 0; i < MAX_CL_BUFFERS; ++i) {
        cl_buffer& b = g_cl_buffer_pool[i];
        if (b.size == 0) {
            b.mem = mem;
            b.size = size;
            return;
        }
    }
    fprintf(stderr, "WARNING: cl buffer pool full, increase MAX_CL_BUFFERS\n");
    clReleaseMemObject(mem);
}

static cl_int ggml_cl_h2d_tensor_2d(cl_command_queue queue, cl_mem dst, size_t offset, const struct ggml_tensor * src, uint64_t i3, uint64_t i2, cl_event* ev) {
    cl_int err;
    const uint64_t ne0 = src->ne[0];
    const uint64_t ne1 = src->ne[1];
    const uint64_t nb0 = src->nb[0];
    const uint64_t nb1 = src->nb[1];
    const uint64_t nb2 = src->nb[2];
    const uint64_t nb3 = src->nb[3];
    const enum ggml_type type = src->type;
    const size_t ts = ggml_type_size(type);
    const size_t bs = ggml_blck_size(type);

    const void * x = (const void *) ((const char *) src->data + i2*nb2 + i3*nb3);
    if (nb0 == ts && nb1 == ts*ne0/bs) {
        err = clEnqueueWriteBuffer(queue, dst, CL_FALSE, offset, ne1*nb1, x, 0, NULL, ev);
        return err;
    }
    if (nb0 == ts) {
        const size_t buffer_origin[3] = { offset, 0, 0 };
        const size_t host_origin[3] = { 0, 0, 0 };
        const size_t region[3] = { ts*ne0/bs, ne1, 1 };
        err = clEnqueueWriteBufferRect(queue, dst, CL_FALSE, buffer_origin, host_origin, region, ts*ne0/bs, 0, nb1, 0, x, 0, NULL, ev);
        return err;
    }
    for (uint64_t i1 = 0; i1 < ne1; i1++) {
        // pretend the row is a matrix with cols=1
        const size_t buffer_origin[3] = { offset, i1, 0 };
        const size_t host_origin[3] = { 0, 0, 0 };
        const size_t region[3] = { ts/bs, ne0, 1 };
        err = clEnqueueWriteBufferRect(queue, dst, CL_FALSE, buffer_origin, host_origin, region, 0, 0, nb0, 0, ((const char *)x) + i1*nb0, 0, NULL, ev);
        if (err != CL_SUCCESS) {
            break;
        }
    }
    return err;
}

static void ggml_cl_mul_mat_f32(const ggml_tensor * src0, const ggml_tensor * src1, ggml_tensor * dst) {
    const int64_t ne00 = src0->ne[0];
    const int64_t ne01 = src0->ne[1];
    const int64_t ne02 = src0->ne[2];
    const int64_t ne03 = src0->ne[3];

    const int64_t ne10 = src1->ne[0];
    const int64_t ne11 = src1->ne[1];

    const int nb2  = dst->nb[2];
    const int nb3  = dst->nb[3];

    const float alpha = 1.0f;
    const float beta = 0.0f;
    const int x_ne = ne01 * ne00;
    const int y_ne = ne11 * ne10;
    const int d_ne = ne11 * ne01;

    size_t x_size;
    size_t y_size;
    size_t d_size;
    cl_mem d_X;
    if (src0->backend == GGML_BACKEND_CL) {
        d_X = *(cl_mem*) src0->data;
    } else {
        d_X = ggml_cl_pool_malloc(sizeof(ggml_fp16_t) * x_ne, &x_size, CL_MEM_READ_ONLY);
    }
    cl_mem d_Y = ggml_cl_pool_malloc(sizeof(float) * y_ne, &y_size, CL_MEM_READ_ONLY);
    cl_mem d_D = ggml_cl_pool_malloc(sizeof(float) * d_ne, &d_size, CL_MEM_WRITE_ONLY);

    for (int64_t i03 = 0; i03 < ne03; i03++) {
        for (int64_t i02 = 0; i02 < ne02; i02++) {
            // copy data to device
            if (src0->backend != GGML_BACKEND_CL) {
                CL_CHECK(ggml_cl_h2d_tensor_2d(queue, d_X, 0, src0, i03, i02, NULL));
            }
            CL_CHECK(ggml_cl_h2d_tensor_2d(queue, d_Y, 0, src1, i03, i02, NULL));

            CL_CHECK(clFinish(queue));

            // compute
            cl_event ev_sgemm;
            clblast::StatusCode status = clblast::Gemm<cl_float>(clblast::Layout::kColMajor,
                                                       clblast::Transpose::kYes, clblast::Transpose::kNo,
                                                       ne01, ne11, ne10,
                                                       alpha,
                                                       d_X, 0, ne00,
                                                       d_Y, 0, ne10,
                                                       beta,
                                                       d_D, 0, ne01,
                                                       &queue, &ev_sgemm);

            if (status != clblast::StatusCode::kSuccess) {
                GGML_ASSERT(false);
            }

            // copy dst to host
            float * d = (float *) ((char *) dst->data + i02*nb2 + i03*nb3);
            CL_CHECK(clEnqueueReadBuffer(queue, d_D, true, 0, sizeof(float) * d_ne, d, 1, &ev_sgemm, NULL));
        }
    }

    if (src0->backend != GGML_BACKEND_CL) {
        ggml_cl_pool_free(d_X, x_size);
    }
    ggml_cl_pool_free(d_Y, y_size);
    ggml_cl_pool_free(d_D, d_size);
}

static void ggml_cl_mul_mat_f16(const ggml_tensor * src0, const ggml_tensor * src1, ggml_tensor * dst, void * wdata, size_t /* wsize */) {
    GGML_ASSERT(fp16_support);

    const int64_t ne00 = src0->ne[0];
    const int64_t ne01 = src0->ne[1];
    const int64_t ne02 = src0->ne[2];
    const int64_t ne03 = src0->ne[3];

    const int64_t ne10 = src1->ne[0];
    const int64_t ne11 = src1->ne[1];

    const int nb10 = src1->nb[0];
    const int nb11 = src1->nb[1];
    const int nb12 = src1->nb[2];
    const int nb13 = src1->nb[3];

    const int nb2  = dst->nb[2];
    const int nb3  = dst->nb[3];

    const ggml_fp16_t alpha = ggml_fp32_to_fp16(1.0f);
    const ggml_fp16_t beta = ggml_fp32_to_fp16(0.0f);
    const int x_ne = ne01 * ne00;
    const int y_ne = ne11 * ne10;
    const int d_ne = ne11 * ne01;

    size_t x_size;
    size_t y_size;
    size_t d_size;
    cl_mem d_X;
    if (src0->backend == GGML_BACKEND_CL) {
        d_X = *(cl_mem*) src0->data;
    } else {
        d_X = ggml_cl_pool_malloc(sizeof(ggml_fp16_t) * x_ne, &x_size, CL_MEM_READ_ONLY);
    }
    cl_mem d_Y = ggml_cl_pool_malloc(sizeof(ggml_fp16_t) * y_ne, &y_size, CL_MEM_READ_ONLY);
    cl_mem d_D = ggml_cl_pool_malloc(sizeof(ggml_fp16_t) * d_ne, &d_size, CL_MEM_WRITE_ONLY);

    bool src1_cont_rows = nb10 == sizeof(float);
    bool src1_cont_cols = (size_t)nb11 == ne11*sizeof(float);

    for (int64_t i03 = 0; i03 < ne03; i03++) {
        for (int64_t i02 = 0; i02 < ne02; i02++) {
            // copy src0 to device
            if (src0->backend != GGML_BACKEND_CL) {
                CL_CHECK(ggml_cl_h2d_tensor_2d(queue, d_X, 0, src0, i03, i02, NULL));
            }

            // convert src1 to fp16
            // TODO: use multiple threads
            ggml_fp16_t * const tmp = (ggml_fp16_t *) wdata + (ne11 * ne10) * (i03 * ne02 + i02);
            char * src1i = (char *) src1->data + i03*nb13 + i02*nb12;
            if (src1_cont_rows) {
                if (src1_cont_cols) {
                    ggml_fp32_to_fp16_row((float *) src1i, tmp, ne10*ne11);
                }
                else {
                    for (int64_t i01 = 0; i01 < ne11; i01++) {
                        ggml_fp32_to_fp16_row((float *) (src1i + i01*nb11), tmp + i01*ne10, ne10);
                    }
                }
            }
            else {
                for (int64_t i01 = 0; i01 < ne11; i01++) {
                    for (int64_t i00 = 0; i00 < ne10; i00++) {
                        // very slow due to no inlining
                        tmp[i01*ne10 + i00] = ggml_fp32_to_fp16(*(float *) (src1i + i01*nb11 + i00*nb10));
                    }
                }
            }

            // copy src1 to device
            CL_CHECK(clEnqueueWriteBuffer(queue, d_Y, false, 0, sizeof(ggml_fp16_t) * y_ne, tmp, 0, NULL, NULL));

            CL_CHECK(clFinish(queue));

            // compute
            cl_event ev_sgemm;
            clblast::StatusCode status = clblast::Gemm<cl_half>(clblast::Layout::kColMajor,
                                                       clblast::Transpose::kYes, clblast::Transpose::kNo,
                                                       ne01, ne11, ne10,
                                                       alpha,
                                                       d_X, 0, ne00,
                                                       d_Y, 0, ne10,
                                                       beta,
                                                       d_D, 0, ne01,
                                                       &queue, &ev_sgemm);

            if (status != clblast::StatusCode::kSuccess) {
                GGML_ASSERT(false);
            }

            // copy dst to host, then convert to float
            CL_CHECK(clEnqueueReadBuffer(queue, d_D, true, 0, sizeof(ggml_fp16_t) * d_ne, tmp, 1, &ev_sgemm, NULL));

            float * d = (float *) ((char *) dst->data + i02*nb2 + i03*nb3);

            ggml_fp16_to_fp32_row(tmp, d, d_ne);
        }
    }

    if (src0->backend != GGML_BACKEND_CL) {
        ggml_cl_pool_free(d_X, x_size);
    }
    ggml_cl_pool_free(d_Y, y_size);
    ggml_cl_pool_free(d_D, d_size);
}

static void ggml_cl_mul_mat_q_f32(const ggml_tensor * src0, const ggml_tensor * src1, ggml_tensor * dst) {
    const int64_t ne00 = src0->ne[0];
    const int64_t ne01 = src0->ne[1];
    const int64_t ne02 = src0->ne[2];
    const int64_t ne03 = src0->ne[3];

    const int64_t ne10 = src1->ne[0];
    const int64_t ne11 = src1->ne[1];

    const int nb2  = dst->nb[2];
    const int nb3  = dst->nb[3];
    const ggml_type type = src0->type;
    const bool mul_mat_vec = ne11 == 1;

    const float alpha = 1.0f;
    const float beta = 0.0f;
    const int x_ne = ne01 * ne00;
    const int y_ne = ne11 * ne10;
    const int d_ne = ne11 * ne01;
    const size_t q_sz = ggml_type_size(type) * x_ne / ggml_blck_size(type);

    size_t x_size;
    size_t y_size;
    size_t d_size;
    size_t q_size;
    cl_mem d_X;
    if (!mul_mat_vec) {
        d_X = ggml_cl_pool_malloc(sizeof(float) * x_ne, &x_size, CL_MEM_READ_WRITE);
    }
    cl_mem d_Y = ggml_cl_pool_malloc(sizeof(float) * y_ne, &y_size, CL_MEM_READ_ONLY);
    cl_mem d_D = ggml_cl_pool_malloc(sizeof(float) * d_ne, &d_size, CL_MEM_WRITE_ONLY);
    cl_mem d_Q;
    if (src0->backend == GGML_BACKEND_CPU) {
        d_Q = ggml_cl_pool_malloc(q_sz, &q_size, CL_MEM_READ_ONLY);
    }

    cl_kernel* to_fp32_cl = ggml_get_to_fp32_cl(type);
    cl_kernel* dmmv = ggml_get_dequantize_mul_mat_vec_cl(type);
    GGML_ASSERT(to_fp32_cl != nullptr);

    for (int64_t i03 = 0; i03 < ne03; i03++) {
        for (int64_t i02 = 0; i02 < ne02; i02++) {
            cl_event ev_sgemm;

            // copy src0 to device if necessary
            if (src0->backend == GGML_BACKEND_CPU) {
                CL_CHECK(ggml_cl_h2d_tensor_2d(queue, d_Q, 0, src0, i03, i02, NULL));
            } else if (src0->backend == GGML_BACKEND_CL) {
                d_Q = *(cl_mem*) src0->data;
            } else {
                GGML_ASSERT(false);
            }
            if (mul_mat_vec) { // specialized dequantize_mul_mat_vec kernel
                // copy src1 to device
                CL_CHECK(ggml_cl_h2d_tensor_2d(queue, d_Y, 0, src1, i03, i02, NULL));

                // compute
                const size_t global = ne01 * CL_DMMV_BLOCK_SIZE;
                const size_t local = CL_DMMV_BLOCK_SIZE;
                const cl_int ncols = ne00;
                CL_CHECK(clSetKernelArg(*dmmv, 0, sizeof(cl_mem), &d_Q));
                CL_CHECK(clSetKernelArg(*dmmv, 1, sizeof(float) * local, NULL));
                CL_CHECK(clSetKernelArg(*dmmv, 2, sizeof(cl_mem), &d_Y));
                CL_CHECK(clSetKernelArg(*dmmv, 3, sizeof(cl_mem), &d_D));
                CL_CHECK(clSetKernelArg(*dmmv, 4, sizeof(cl_int), &ncols));
                CL_CHECK(clFinish(queue));
                CL_CHECK(clEnqueueNDRangeKernel(queue, *dmmv, 1, NULL, &global, &local, 0, NULL, &ev_sgemm));
            } else { // general dequantization kernel + CLBlast matrix matrix multiplication
                // convert src0 to fp32 on device
                const size_t global = x_ne;
                CL_CHECK(clSetKernelArg(*to_fp32_cl, 0, sizeof(cl_mem), &d_Q));
                CL_CHECK(clSetKernelArg(*to_fp32_cl, 1, sizeof(cl_mem), &d_X));
                CL_CHECK(clFinish(queue));
                CL_CHECK(clEnqueueNDRangeKernel(queue, *to_fp32_cl, 1, NULL, &global, NULL, 0, NULL, NULL));

                // copy src1 to device
                CL_CHECK(ggml_cl_h2d_tensor_2d(queue, d_Y, 0, src1, i03, i02, NULL));

                // wait for conversion
                CL_CHECK(clFinish(queue));

                // compute
                clblast::StatusCode status = clblast::Gemm<cl_float>(clblast::Layout::kColMajor,
                                                           clblast::Transpose::kYes, clblast::Transpose::kNo,
                                                           ne01, ne11, ne10,
                                                           alpha,
                                                           d_X, 0, ne00,
                                                           d_Y, 0, ne10,
                                                           beta,
                                                           d_D, 0, ne01,
                                                           &queue, &ev_sgemm);

                if (status != clblast::StatusCode::kSuccess) {
                    GGML_ASSERT(false);
                }
            }

            // copy dst to host
            float * d = (float *) ((char *) dst->data + i02*nb2 + i03*nb3);
            CL_CHECK(clEnqueueReadBuffer(queue, d_D, true, 0, sizeof(float) * d_ne, d, 1, &ev_sgemm, NULL));
            clReleaseEvent(ev_sgemm);
        }
    }

    if (!mul_mat_vec) {
        ggml_cl_pool_free(d_X, x_size);
    }
    ggml_cl_pool_free(d_Y, y_size);
    ggml_cl_pool_free(d_D, d_size);
    if (src0->backend == GGML_BACKEND_CPU) {
        ggml_cl_pool_free(d_Q, q_size);
    }
}


bool ggml_cl_can_mul_mat(const struct ggml_tensor * src0, const struct ggml_tensor * src1, struct ggml_tensor * dst) {
    const int64_t ne10 = src1->ne[0];

    const int64_t ne0 = dst->ne[0];
    const int64_t ne1 = dst->ne[1];

    // TODO: find the optimal values for these
    if ((src0->type == GGML_TYPE_F32 || src0->type == GGML_TYPE_F16 || ggml_is_quantized(src0->type)) &&
        src1->type == GGML_TYPE_F32 &&
        dst->type == GGML_TYPE_F32 &&
        ((ne0 >= 32 && ne1 >= 32 && ne10 >= 32) || src0->backend == GGML_BACKEND_CL)) {
        return true;
    }

    return false;
}

bool ggml_cl_mul_mat_use_f16(const struct ggml_tensor * src0, const struct ggml_tensor * src1, struct ggml_tensor * /* dst */) {
    // If device doesn't support FP16
    if (!fp16_support) {
        return false;
    }

    size_t src0_sz = ggml_nbytes(src0);
    size_t src1_sz = ggml_nbytes(src1);

    // mul_mat_q: src0 is converted to fp32 on device
    size_t mul_mat_q_transfer = src0_sz + src1_sz;

    // mul_mat_f16: src1 is converted to fp16 on cpu
    size_t mul_mat_f16_transfer = src0_sz + sizeof(ggml_fp16_t) * ggml_nelements(src1);

    // choose the smaller one to transfer to the device
    // TODO: this is not always the best choice due to the overhead of converting to fp16
    return mul_mat_f16_transfer < mul_mat_q_transfer;
}

void ggml_cl_mul_mat(const struct ggml_tensor * src0, const struct ggml_tensor * src1, struct ggml_tensor * dst, void * wdata, size_t wsize) {
    GGML_ASSERT(ggml_cl_can_mul_mat(src0, src1, dst));

    if (src0->type == GGML_TYPE_F32) {
        ggml_cl_mul_mat_f32(src0, src1, dst);
    }
    else if (src0->type == GGML_TYPE_F16) {
        if (ggml_cl_mul_mat_use_f16(src0, src1, dst)) {
            ggml_cl_mul_mat_f16(src0, src1, dst, wdata, wsize);
        }
        else {
            ggml_cl_mul_mat_q_f32(src0, src1, dst);
        }
    }
    else if (ggml_is_quantized(src0->type)) {
        ggml_cl_mul_mat_q_f32(src0, src1, dst);
    }
    else {
        GGML_ASSERT(false);
    }
}

size_t ggml_cl_mul_mat_get_wsize(const struct ggml_tensor * src0, const struct ggml_tensor * src1, struct ggml_tensor * dst) {
    if (ggml_cl_mul_mat_use_f16(src0, src1, dst)) {
        return ggml_nelements(src1) * sizeof(ggml_fp16_t);
    }
    return 0;
}

void ggml_cl_transform_tensor(ggml_tensor * tensor) {
    const int64_t ne0 = tensor->ne[0];
    const int64_t ne1 = tensor->ne[1];
    const int64_t ne2 = tensor->ne[2];
    const int64_t ne3 = tensor->ne[3];

    const ggml_type type = tensor->type;
    const size_t q_sz = ggml_type_size(type) * ne0 * ne1 * ne2 * ne3 / ggml_blck_size(type);

    size_t q_size;
    cl_mem* dst = (cl_mem*) malloc(sizeof(cl_mem));
    *dst = ggml_cl_pool_malloc(q_sz, &q_size, CL_MEM_READ_ONLY);

    // copy tensor to device
    for (int64_t i3 = 0; i3 < ne3; i3++) {
        for (int64_t i2 = 0; i2 < ne2; i2++) {
            int i = i3*ne2 + i2;
            CL_CHECK(ggml_cl_h2d_tensor_2d(queue, *dst, i*ne0*ne1, tensor, i3, i2, NULL));
        }
    }

    CL_CHECK(clFinish(queue));

    tensor->data = dst;
    tensor->backend = GGML_BACKEND_CL;
}