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


int main(int argc, char **argv){
    unsigned char convert_table[] = {
        //origin    converted
        0xeb,0x07,  0xeb,0x0a,  //first address to find!
        0xe1,0x00,  0xe1,0x04,
        0xe7,0x04,  0xe7,0x08,
        0xe2,0xc0,  0xe2,0x80,
        0x60,0x13,  0xe0,0x00
    };
    if(argc == 1){
        printf("\033[1;31m");           //red
        printf("error: ");
        printf("\033[0;37m");           //white
        printf("no input and output file!\n");
        return 1;
    }
    if(argc == 2){
        printf("\033[1;31m");           //red
        printf("error: ");
        printf("\033[0;37m");           //white
        printf("no output file!\n");
        return 2;
    }

    if(access(argv[1], F_OK ) == 0) {
        //none
    } else {
        printf("\033[1;31m");           //red
        printf("error: ");
        printf("\033[0;37m");           //white
        printf("cannot open file!\n");
        return 3;
    }
    printf("\033[0;37m");               //white text

    FILE * file;                        //file pointer
    file = fopen(argv[1], "rb");        //open file
    fseek(file, 0L, SEEK_END);          //seek file size
    int filesize = ftell(file);         //get file size

    unsigned char* filedata = NULL;     //make file data table
    filedata = malloc(filesize);
    for(int i=0; i<filesize; i++){
        filedata[i] = 0x00;
    }

    fseek(file, 0, SEEK_SET);
    int fread_result = fread(filedata, filesize, 1, file); //set file data in filedata table
    printf("fread result: %d\n",fread_result);

    fclose(file);                       //close input file

    int addr = 0;                       //address of data to change
    printf("filesize: %d\n\n",filesize);

    //////////////////////FIND SEQUENCE TO CHANGE/////
    for(int i=0; i<filesize-80; i++){
        if(filedata[i] == convert_table[0] && filedata[i+1] == convert_table[1]){
            //for(int c=0; c<20;c++){printf("%02x ",filedata[i+c]);}
            printf("%08x %02x%02x -> %08x %02x%02x\n",i,convert_table[0],convert_table[1], i,convert_table[2],convert_table[3]);
            filedata[i] = convert_table[2];
            filedata[i+1] = convert_table[3];
            addr = i;
            break;
        }
    }

    for(int a=4; a<sizeof(convert_table); a=a+4){
        for(int i=addr; i<addr+100;i++){
            if(filedata[i] == convert_table[a+0] && filedata[i+1] == convert_table[a+1]){
                printf("%08x %02x%02x -> %08x %02x%02x\n",i,convert_table[a+0],convert_table[a+1], i,convert_table[a+2],convert_table[a+3]);
                filedata[i] = convert_table[a+2];
                filedata[i+1] = convert_table[a+3];
                break;
            }
        }
    }

    if(addr == 0){
        printf("\033[1;31m");           //red
        printf("error: ");
        printf("\033[0;37m");           //white
        printf("no valid file or no data to edit\n");
        return 4;
    }



    file = fopen(argv[2], "wb");        //open output file

    //write final data in output file
    fwrite(filedata , sizeof(char) , filesize , file);

    fclose(file);                       //close output file
    free(filedata);
    return 1;
}