#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/mman.h>
#include <sys/types.h>
#include <fcntl.h>
#include <unistd.h>
#include <OpenCL/opencl.h>
#include <oclUtils.h>

#define OUT_PARAM_NUM 2

typedef struct {
    caddr_t file_mmap;
    off_t size;
} st_mmap_t;

/*与えられたsizeをfix_byte_sizeの倍数にする(丸め込むっていうのかな？)*/
static int
fix_byte(int size,int fix_byte_size)
{
    size = (size/fix_byte_size)*fix_byte_size  + ((size%fix_byte_size)!= 0)*fix_byte_size;
    
    return size;
}


static st_mmap_t
my_mmap(char *filename)
{

    /*マッピングだよ!*/
    int fd = -1;
    int map = MAP_PRIVATE;
    st_mmap_t st_mmap;
    struct stat sb;
    
    if ((fd=open(filename,O_RDONLY,0666))==0) {
	fprintf(stderr,"can't open %s\n",filename);
    }
    
    if (fstat(fd,&sb)) {
	fprintf(stderr,"can't fstat %s\n",filename);
    }

    printf("file size %d\n",(int)sb.st_size);
   
    /*sizeをページングサイズの倍数にあわせる*/
    st_mmap.size = fix_byte(sb.st_size,4096);

    printf("fix 4096byte file size %d\n",(int)st_mmap.size);

    st_mmap.file_mmap = (char*)mmap(NULL,st_mmap.size,PROT_READ,map,fd,(off_t)0);
    if (st_mmap.file_mmap == (caddr_t)-1) {
	fprintf(stderr,"Can't mmap file\n");
	perror(NULL);
	exit(0);
    }

    return st_mmap;

}



int main(int args, char *argv[]) 
{

    char *filename = 0;

    for (int i = 1; argv[i]; ++i) {	
	if (strcmp(argv[i], "-file") == 0) {
	    filename = argv[i+1];
	} else if (strcmp(argv[i], "-help")) {
            printf("Usage: ./word_count [-file filename]\n");
        }
    }

    if (filename == 0) {
        printf("Usage: ./word_count [-file filename]\n");
        return 0;
    }

    //指定されたファイルをメモリにmap
    st_mmap_t st_mmap = my_mmap(filename);

    //kernelファイルの大きさ取得して、メモリ確保
    int fd = -1;
    const char *kernel_filename =  "./word_count.cl";
    if ((fd=open(kernel_filename,O_RDONLY,0666))==0) {
        fprintf(stderr,"can't open %s\n",kernel_filename);
    }

    struct stat sb;
    if (fstat(fd,&sb)) {
        fprintf(stderr,"can't fstat %s\n",filename);
    }

    size_t source_size = sb.st_size;
    void *source_str = malloc(source_size);

    int err = read(fd, source_str, source_size);
    if (err == -1) {
        fprintf(stderr,"can't read %s\n",filename);
    }

    close(fd);

    cl_platform_id platform_id = NULL;
    cl_uint ret_num_platforms = NULL;
    cl_int ret = clGetPlatformIDs(1, &platform_id, &ret_num_platforms);

    cl_device_id device_id = NULL;
    cl_uint ret_num_devices = NULL;
    // CL_DEVICE_TYPE_CPU, CL_DEVICE_TYPE_GPU, と指定できる
    // CL_DEVICE_TYPE_DEFAULT はどうなるのか
    ret = clGetDeviceIDs( platform_id, CL_DEVICE_TYPE_DEFAULT, 
                          1, &device_id, &ret_num_devices);

    oclCheckError(ret, CL_SUCCESS);

    //OpenCLコンテキストの作成
    cl_context context = clCreateContext( NULL, 1, &device_id, NULL, NULL, &ret);
    oclCheckError(ret, CL_SUCCESS);
    cl_command_queue command_queue = clCreateCommandQueue(context, device_id, 0, &ret);
    oclCheckError(ret, CL_SUCCESS);
    // カーネルプログラムを読み込む
    cl_program program = clCreateProgramWithSource(context, 1, (const char **)&source_str,
                                                   (const size_t *)&source_size, &ret);
    ret = clBuildProgram(program, 1, &device_id, NULL, NULL, NULL);

    oclCheckError(ret, CL_SUCCESS);

    //カーネルプログラムをビルド
    //Task選択にあたる
    cl_kernel kernel = clCreateKernel(program, "word_count", &ret);
    oclCheckError(ret, CL_SUCCESS);

    //カウントするテキストデータのメモリオブジェクト
    cl_mem text_memobj = clCreateBuffer(context, CL_MEM_READ_ONLY, 
                                        st_mmap.size * sizeof(char), NULL, &ret);

    ret = clEnqueueWriteBuffer(command_queue, text_memobj,
                               CL_TRUE, 0, st_mmap.size, (char*)st_mmap.file_mmap,
                               0, NULL, NULL);

    oclCheckError(ret, CL_SUCCESS);

    // 必要なパラメータのオブジェクト
    cl_mem param_memobj = clCreateBuffer(context, CL_MEM_READ_ONLY, 
                                         sizeof(int), NULL, &ret);

    ret = clEnqueueWriteBuffer(command_queue, param_memobj,
                               CL_TRUE, 0, sizeof(int), (int*)(&st_mmap.size),
                               0, NULL, NULL);

    oclCheckError(ret, CL_SUCCESS);

    
    /*
     * 並列度の計算
     * wcするファイルの大きさに合わせる
     *
     */

    // このdivi_size はどうやって決めるよ
    int divi_size = 1024;
    st_mmap.size / 1024;
    

    size_t global_work_size = 4;

    // 行数、単語数を格納する2のint配列
    int out_size = sizeof(int) * OUT_PARAM_NUM * global_work_size;
    cl_mem out_memobj = clCreateBuffer(context, CL_MEM_WRITE_ONLY, 
                                       out_size * sizeof(char), NULL, &ret);

    oclCheckError(ret, CL_SUCCESS);


    // 引数のSet
    // memory object にしなくてもできるsetできるかも
    ret = clSetKernelArg(kernel, 0, sizeof(cl_mem), (void *)&text_memobj);
    ret |= clSetKernelArg(kernel, 1, sizeof(cl_mem), (void *)&param_memobj);
    ret |= clSetKernelArg(kernel, 2, sizeof(cl_mem), (void *)&out_memobj);

    oclCheckError(ret, CL_SUCCESS);

    /* 
     * kernel実行
　　 * 並列に処理せずに work-item ひとつで動かしたい場合は、clEnqueueNDRangeKernel の簡易版 clEnqueueTask が使える
     *
    */　　 

    //ret = clEnqueueTask(command_queue, kernel, 0, NULL, NULL);
    // global_work_size は配列。並列動作させる時の次元数にあわせて、配列の次元数も決まるはず
    ret = clEnqueueNDRangeKernel(command_queue, kernel, 1, NULL, &global_work_size, NULL, 0, NULL, NULL);

    oclCheckError(ret, CL_SUCCESS);

    int *out_data = (int*)malloc(out_size);

    // 演算結果の読み込み
    ret = clEnqueueReadBuffer(command_queue, out_memobj, CL_TRUE, 0, 
                              out_size * sizeof(char), out_data, 0, NULL, NULL);

    oclCheckError(ret, CL_SUCCESS);

    for (int i = 0; i < global_work_size; i++) {
        for (int j = 0; j < OUT_PARAM_NUM; j++) {
            printf("%d ", out_data[i*OUT_PARAM_NUM+j]);
        }
        printf("\n");
    }

    clFlush(command_queue);
    clFinish(command_queue);
    clReleaseKernel(kernel);
    clReleaseProgram(program);
    clReleaseMemObject(text_memobj);
    clReleaseMemObject(param_memobj);
    clReleaseMemObject(out_memobj);
    clReleaseCommandQueue(command_queue);
    clReleaseContext(context);

    free(source_str);
    free(out_data);

    return 0;

}