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

#ifdef __APPLE__
#include <OpenCL/opencl.h>
#else
#include <CL/cl.h>
#endif

#define fileName "kernel.cl"

char openKernelFile(char* fn);


//General Steps for OpenCL Programming
//  1. Get the Platform and Devices
//  2. Create the context for the device or devices you want to use
//  3. Create the command queue for the context
//  4. Create the program with source. Ie. Open the file containing the kernel functions this program will use
//  5. Build the program
//  6. Create the kernel you want to use in this program


int main() {

    cl_int err;
    cl_platform_id platformID;
    cl_device_id deviceID;

    cl_context context;
    cl_command_queue commandQ;
    cl_program program;
    cl_kernel kernel;

     char *initializeKernel = openKernelFile(fileName);


    /* 1. Getting information about the platform and device to use */
    err = clGetPlatformIDs(1, &platformID, NULL);
    err = clGetDeviceIDs(platformID, CL_DEVICE_TYPE_GPU, 1, &deviceID, NULL);

    /* 2. Creating and checking the context */
    context = clCreateContext(NULL, 1, &deviceID, NULL, NULL, &err);

    if (err == 0)
        printf("Context created successfully\n");
    else
        printf("Context failed to create with error code: %d\n", err);

    /* 3. Creating and checking the Queue */

    commandQ = clCreateCommandQueue(context, deviceID, NULL, &err);

    if (err == 0)
        printf("Command Queue created successfully\n");
    else
        printf("Command Queue failed to create with error code: %d\n", err);

    /* 4. Creating the program with source from file */

    program = clCreateProgramWithSource(context, 1, (const char**)&initializeKernel, NULL, &err);

    if (err == 0)
        printf("Program creation from source file was done successfully\n");
    else
        printf("Program creating from source file has failed with error code: %d\n", err);


    /* 5. Building the program */

    err = clBuildProgram(program, 0, NULL, NULL, NULL, NULL);

    if (err == 0)
        printf("Building the program was done successfully\n");
    else
        printf("Building the program has failed with error code: %d\n", err);

    /* 6. Create the kernel */

    kernel = clCreateKernel(program, "helloWorld", &err);

    if (err = 0)
        printf("Creating the kernel was done successfully\n");
    else
        printf("Creating the kernel has failed with error code: %d", err);


    return 0;


}

char openKernelFile(char* fn) {

    FILE* kernelFile;
    char* programSource;
    size_t programSize;

    kernelFile = fopen(fn, "rb"); //Change this to r if ! using windows

    if (!kernelFile) {

        printf("Kernel file loading failed\nExiting Program\n");
        exit(1);
    }

    fseek(kernelFile, 0, SEEK_END);
    programSize = ftell(kernelFile);
    rewind(kernelFile);
    programSource = (char*)malloc(programSize + 1);
    programSource[programSize] = '\0';
    fread(programSource, sizeof(char), programSize, kernelFile);

    fclose(kernelFile);

    return programSource;

}