#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <dirent.h>
#include <sys/stat.h>

typedef char String[1024];

typedef struct Node{

    String filename;
    int instances;
    struct Node* nextNode;

}Filenode;

void toLowerCase(String text){

    int i;

    for(i = 0 ; text[i] ; i++){
        if(text[i] >= 65 && text[i] <= 90){
            text[i] += 32;
        }
    }

}

int searchkeyword(String searchtext,String keyword){

    int i,j,k;
    int notfound = 1;
    int instances = 0;

    toLowerCase(searchtext);
    toLowerCase(keyword);

    for(i = 0 ; i < strlen(searchtext) ; i++){

        notfound = 1;

        for(j = 0, k = i ; j < strlen(keyword) && notfound ; j++, k++){

            if(keyword[j] != searchtext[k]){
                notfound = 0;
            }

        }

        if(notfound){
            instances++;
        }

    }

    return instances;

}

int search(String filename, String keyword){

    int found = 0;
    FILE *fp;
    String phrase;

    if(strstr(filename,".txt") != NULL){

        fp = fopen(filename,"r");

        if(fp == NULL){
            printf("\n### FILE NOT FOUND ###\n");
        }else{

            while(fscanf(fp, "%s", phrase) == 1){
                //printf("%s",phrase);
                toLowerCase(phrase);
                toLowerCase(keyword);
                if(strstr(phrase, keyword) != NULL){
                    found++;
                    //printf(" +++ hit");
                }
                //printf("\n");
            }

        }

        fclose(fp);

    }else if(strstr(filename,".doc") != NULL){

        fp = fopen(filename,"rb");

        if(fp == NULL){
            printf("\n### FILE NOT FOUND ###\n");
        }else{

            char chdump;
            String buffer;
            int ctr = 0;

            fseek(fp,2560,SEEK_SET);

            do{
                fread(&chdump,1,1,fp);
                buffer[ctr] = chdump;
                ctr++;
            }while(chdump >= 32 && chdump <= 126);

            found = searchkeyword(buffer,keyword);

        }

        fclose(fp);

    }

    return found;

}

void newFilenode(String filename, int instances, Filenode** filelist){

    Filenode* newNode = malloc(sizeof(Filenode));
    strcpy(newNode->filename,filename);
    newNode->instances = instances;
    newNode->nextNode = *filelist;
    *filelist = newNode;

}

void traverse(String pathname, String oldpathname, String keyword, Filenode** filelist){

  chdir(pathname);

  DIR *d = opendir(".");
  struct dirent *dir;

  if (d){

    while ((dir = readdir(d)) != NULL){

        if(!(strcmp(dir->d_name,".") == 0)&&!(strcmp(dir->d_name,"..") == 0)){

            char *fi = dir->d_name;
            struct stat fileinfo;

            int status = stat(fi, &fileinfo);

            if (status != 0) {
                return;
            }

            if (S_ISDIR (fileinfo.st_mode)) {

               String newpathname;
               strcpy(newpathname, pathname);
               strcat(newpathname,"\\");
               strcat(newpathname,dir->d_name);
               printf("%s\n",newpathname);
               traverse(newpathname,pathname,keyword,filelist);

            }else if (S_ISREG (fileinfo.st_mode)) {

               int instances = search(dir->d_name,keyword);

               if(instances > 0){

                String newpathname;
                strcpy(newpathname, pathname);
                strcat(newpathname,"\\");
                strcat(newpathname,dir->d_name);

                newFilenode(newpathname,instances,filelist);

               }

            }

        }

    }

    closedir(d);

  }

    chdir(oldpathname);

}

int main(){

    String keyword;
    String pathname;
    Filenode* filelist = NULL;

    printf("Pathname: ");
    scanf("%s",pathname);

    printf("Keyword: ");
    scanf("%s",keyword);

    printf("\n");

    if(chdir(pathname) == 0){
        traverse(pathname,"C:\\",keyword,&filelist);
    }else{
        printf("Invalid path name.\n");
    }

    if(filelist != NULL){

        while(filelist != NULL){

            printf("\nPath: %s\n",filelist->filename);
            printf("Number of instances: %d\n",filelist->instances);
            filelist = filelist->nextNode;

        }

    }

    return 0;

}