#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <signal.h>
#include <string.h>
#include <sys/wait.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <errno.h>

#define BUFFER 1500
#define READ 0
#define WRITE 1

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


    //verificacao do numero de argumentos
    if (argc != 3) {
        printf("Numero errado de argumentos.\n");
        printf("Usage: %s <directory> <filename>\n", argv[0]);
        exit(1);
    }

    char strFgets[BUFFER], wordsPath[BUFFER], temp[BUFFER], text[BUFFER];

    char file[BUFFER];
    sprintf(file, "%s/words.txt", argv[1]);

    sprintf(temp, "%s/temp%s.txt", argv[1], argv[2]);

    char *number = malloc(strlen(argv[2]) + 1);

    if(number == NULL){
       exit(1);
    }
    strcpy(number, argv[2]);

    char *dot = strrchr(number,'.');
    *dot = '\0';


    int myPipe[2];

    //abrir o ficheiro das palavras a procurar
    FILE *words;
    words = fopen(file,"r");


    //verifica se o ficheiro existe
    if(words == NULL){
        perror("words.txt");
        exit(1);
        }

    fclose(words);

    char* outputFilename = malloc(strlen(argv[2]) + 1);
    strcat(outputFilename, number);
    strcat(outputFilename, ".sw");

    FILE * tempFile = fopen(outputFilename, "w");

    if(tempFile == NULL){
        perror("temp.txt");
        exit(1);
        }

    //criar pipes
    if (pipe (mypipe) == -1){
        fprintf(stderr, "Erro ao criar pipes.\n");
        exit(1);
    }

    //pai
if(pid > 0){

    close(mypipe[WRITE]);

//enquanto o ficheiro onde se encontram as palavras a procurar nao termina,
//continua a procura as palavras no ficheiro de texto passado como 2º argumento
    int read=1;

    while( (fgets(text, BUFFER, words))!= NULL){
    text[strlen(text)-1]='\0';

    char buff[1024];
    read =read(mypipe[READ],buff,1023);

        while(read != 0){

            while(buff[read] != '\0'){

            char *doubleDots = strchr(text, ':');

              if (doubleDots != NULL){
                char* line =readline(mypipe(read));
                fprintf(tempFile, "%s : %s-%s\n", doubleDots + 1, number, text);
              }

            }
        }

    }
        //close(mypipe[READ]);
    wait(NULL);
}

else{
    dup2(mypipe[WRITE], STDOUT_FILENO);
    close(mypipe[READ]);
    execlp("grep", "grep",  "-w", "-o", "-n", "-f", file, temp, NULL);
    perror("grep");
    exit(1);
}

fclose(tempFile);

    return 0;
}

char* readline(int fd){
    char string[1024];
    char currentByte;
    int i = 0;

    while(read(fd, &currentByte, 1) > 0){
        if(currentByte == '\n' || currentByte == '\0'){
            break;
        }

        string[i++] = currentByte;
    }
    string[i] = '\0';

    return string;
}