#define _POSIX_C_SOURCE 200809L
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <sys/un.h>
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <unistd.h>
#include <math.h>

#include "api.h"
#include "conn.h"

#define SOCKNAMEMAX 256 /* should be at least 108 */


#define MEOK "20" /*OK */
// #define ME "21" /* not used */
// #define ME "22" /* not used */
#define MEFP "25" /* file purged */

// #define ME "40" /* not used */
// #define ME "41" /* not used */
#define MESD "42" /* shutting down */
#define MENT "45" /* requested file action not taken */

#define MESY "50" /* syntax error */
// #define ME "51" /* not used */
// #define ME "52" /* not used */
#define MESE "55" /* server error */

// -----------------------------------------------------------------------------
// structs

typedef struct files_s {
    char *filename;
    int locked;
    struct files_s *next;
} files_t;

typedef struct openfiles_s {
    int numOfFiles;
    files_t *f;             /* list of files that are currently opened */
    int validwDir;          /* true if wDir is allocated */
    char *wDir;             /* for files sent from the server after openFile */
    int validrDir;          /* true if rDir is allocated */
    char *rDir;             /* for files read from the server */
    char *createdAndLocked; /* path of the last file that was created and locked */
    int print;              /* whether to print */
    FILE *out;              /* where to print */
} openfiles_t;

/* struct for the files sent from the server */
typedef struct recivedFile_s {
    int64_t pathlen;
    char *path;
    int64_t filelen;
    char *file;
} recivedFile_t;

typedef struct response_s {
    char ME[2];         /* response */
    int meerrno;        /* errno sent by server */
    int64_t numfiles;   /* number of files if sent */
    recivedFile_t *rf;  /* array of files */
} response_t;

// -----------------------------------------------------------------------------
// global variables
static long fd_skt; /* descriptor of the socket */
static char socketName[SOCKNAMEMAX] = ""; /* name of the socket */
static openfiles_t *openedFiles = NULL;

// -----------------------------------------------------------------------------
// helper functions

/* closes every file opened by the client */
int closeEveryFile();
/* closes and frees memory */
int removeOpenFile(const char *);
/* adds element */
int addOpenFile(const char *, const int);
/* checks if the file is open already */
int isOpen(const char *, const int);
/* reads everything the server sent into the variable passed to the function
 * expected == 1 if a file should be sent (if no server errors occurs) */
int reciveData(response_t *, int expected);
/* saves the files in the specified directory */
int storeFilesInDirectory(const char *, int n, recivedFile_t *);
/* frees memory inside response_t element */
void freeResponse(response_t *);
/* initiates the global variables */
int createOpenedFiles();


// -----------------------------------------------------------------------------
int openConnection(const char* sockname, int msec, const struct timespec abstime) {
    if(!sockname){
	errno = EINVAL;
	return -1;
    }

    if(!openedFiles) {
	if(createOpenedFiles()<0) {
	    perror("openConnection: createOpenedfiles");
	    return -1;
	}
    }

    struct sockaddr_un sa;
    struct timespec ts;
    ts.tv_sec = msec/1000;
    ts.tv_nsec = (msec % 1000) * 1000000;
    struct timeval t1, t2; /* for gettimeofday */
    long long start, end; /* to calculate the time elapsed */
    long long elapsedTime;

    /* select socket */
    strncpy(sa.sun_path, sockname, sizeof(sa.sun_path)-1);
    sa.sun_family = AF_UNIX;

    if ((fd_skt = socket(AF_UNIX, SOCK_STREAM, 0)) == -1) {
	errno = EINVAL;
	perror("openConnection: socket");
	return -1;
    }

    if(gettimeofday(&t1, NULL) != 0) {
	perror("openConnection: gettimeofday");
	return -1;
    }

    start = (long long) (t1.tv_sec * 1000000000 + t1.tv_usec * 1000);

    while (connect(fd_skt, (struct sockaddr*) &sa, sizeof(sa)) == -1) {
	gettimeofday(&t2, NULL);
	end = (long long) t2.tv_sec * 1000000000 + t2.tv_usec * 1000;
	elapsedTime = (end - start);

	/* return if more time has elapsed than allowed */
	if (elapsedTime > (abstime.tv_sec * 1000000000) + abstime.tv_nsec) {
	    errno = ETIMEDOUT;
	    return -1;
	}

	nanosleep(&ts, &ts);
    }

    strncpy(socketName, sockname, sizeof(socketName)-1);
    return 0;
}

int closeConnection(const char* sockname) {
    if (!sockname) {
	errno = EINVAL;
	return -1;
    }
    /* if closing a different socket -> error */
    if(strncmp(socketName, "", sizeof(socketName)) != 0
       && strncmp(socketName, sockname, sizeof(socketName)) != 0) {
	errno = EINVAL;
	return -1;
    }
    /* close every file */
    if (closeEveryFile() == -1) {
	perror("closeConnection: closeEveryFile");
	return -1;
    }
    /* close socket */
    if (close(fd_skt) == -1) {
	/* return errno from close */
	return -1;
    }

    memset(socketName, 0, SOCKNAMEMAX);
    return 0;
}

int openFile(const char* pathname, int flags) {
    if(!pathname){
	errno = EINVAL;
	return -1;
    }
    if(!openedFiles){
	errno = EPROTO;
	return -1;
    }
    if(openedFiles->createdAndLocked)
	free(openedFiles->createdAndLocked);
    openedFiles->createdAndLocked = NULL;

    if(strcmp(socketName, "") == 0) {
	errno = ENOTCONN;
	return -1;
    }
    if(isOpen(pathname, flags) == 1) { /* already open */
	return 0;
    }

    /* sent to server the string "openFile|$(pathname)|$(flags)" */
    int leng_flags = snprintf(NULL, 0, "%d", flags);
    long len = strlen("openFile")+1+strlen(pathname)+1+leng_flags+1;
    char *cmd = malloc(len);
    if(!cmd) {
	perror("openFile: malloc");
	return -1;
    }
    memset(cmd, 0, len);
    snprintf(cmd, len, "openFile|%s|%d", pathname, flags);
    len = strnlen(cmd, len);

    /* send cmd */
    if (writen(fd_skt, &len, sizeof(long)) == -1) {
	/* writen sets errno */
	free(cmd);
	return -1;
    }
    if (writen(fd_skt, cmd, len) == -1) {
	/* writen sets errno */
	free(cmd);
	return -1;
    }

    /* recive response */
    response_t *res = calloc(1, sizeof(response_t));
    if(!res){
	perror("openFile: calloc");
	free(cmd);
	return -1;
    }

    /* reciveData(, 0) because if we get a MEOK we dont expect a file */
    if(reciveData(res, 0) < 0) {
	/* errno is set by reciveData */
	freeResponse(res);
	free(res);
	free(cmd);
	return -1;
    }
    if(res->meerrno != 0) {
	/* errno from server */
	freeResponse(res);
	errno = res->meerrno;
	free(res);
	free(cmd);
	return -1;
    }
    if(strncmp(res->ME, MEFP, sizeof(res->ME)) == 0) {
	/* some files were purged */
	if(openedFiles->print){
	    fprintf(openedFiles->out, "\nIl server ha espulso i seguenti file:\n");
	    fflush(openedFiles->out);
	    for(int i=0;i<res->numfiles;++i) {
		fprintf(openedFiles->out, "\t%d) %s\n", i+1, res->rf[i].path);
	    }
	}
	if(openedFiles->wDir) {
	    if(openedFiles->print) {
		fprintf(openedFiles->out, "\tI file espulsi sono stati scritti nella cartella: %s\n", openedFiles->wDir);
		fflush(openedFiles->out);
	    }
	    if(storeFilesInDirectory(openedFiles->wDir, res->numfiles, res->rf) == -1) {
		perror("openFile: storeFilesindirectory");
		freeResponse(res);
		free(res);
		free(cmd);
		return -1;
	    }
	} else {
	    if(openedFiles->print) {
		fprintf(openedFiles->out, "\tI file espulsi non sono stati memorizzati su disco\n");
		fflush(openedFiles->out);
	    }
	}
    }

    if(addOpenFile(pathname, flags) == -1) {
	perror("openFile: addOpenFile");
	return -1;
    }

    if(flags == (O_CREATE | O_LOCK)) {
	if(openedFiles->createdAndLocked)
	    free(openedFiles->createdAndLocked);
	openedFiles->createdAndLocked = calloc(strlen(pathname)+1, sizeof(char));
	if(!openedFiles->createdAndLocked) {
	    perror("openFile: calloc");
	    freeResponse(res);
	    free(res);
	    free(cmd);
	    return -1;
	}
	strcpy(openedFiles->createdAndLocked, pathname);
    }

    freeResponse(res);
    free(res);

    free(cmd);
    return 0;
}

int readFile(const char* pathname, void** buf, size_t* size) {
    if(!pathname) {
	errno = EINVAL;
	return -1;
    }
    if(!openedFiles){
	errno = EPROTO;
	return -1;
    }
    if(openedFiles->createdAndLocked)
	free(openedFiles->createdAndLocked);
    openedFiles->createdAndLocked = NULL;

    if(strcmp(socketName, "") == 0) {
	errno = ENOTCONN;
	return -1;
    }

    if(isOpen(pathname, 0) != 1) { /* if it's not open => error */
	errno = EPERM;
	return -1;
    }

    /* send to server the string readFile|$(pathname)" */
    long len = strlen("readFile")+1+strlen(pathname)+1;
    char *cmd = malloc(len);
    if(!cmd) {
	perror("readFile: malloc");
	return -1;
    }
    memset(cmd, 0, len);
    snprintf(cmd, len, "readFile|%s", pathname);
    len = strnlen(cmd, len);

    /* send cmd */
    if (writen(fd_skt, &len, sizeof(long)) == -1) {
	/* writen sets errno */
	free(cmd);
	return -1;
    }
    if (writen(fd_skt, cmd, len) == -1) {
	/* writen sets errno */
	free(cmd);
	return -1;
    }

    /* recive response */
    response_t *res = calloc(1, sizeof(response_t));
    if(!res){
	perror("readFile: calloc");
	free(cmd);
	return -1;
    }

    /* reciveData(, 1) because if we get a MEOK we expect a file */
    if(reciveData(res, 1) < 0) {
	/* errno is set by reciveData */
	freeResponse(res);
	free(res);
	free(cmd);
	return -1;
    }
    if(res->meerrno != 0) { /* errno from server */
	freeResponse(res);
	errno = res->meerrno;
	free(res);
	free(cmd);
	return -1;
    }

    /* no errors from server */
    if(res->numfiles != 1) {
	freeResponse(res);
	free(res);
	free(cmd);
	errno = EMSGSIZE;
	return -1;
    }
    *size = (size_t) res->rf[0].filelen;
    *buf = malloc(*size);
    if(!*buf) {
	freeResponse(res);
	free(res);
	free(cmd);
	perror("readFile: malloc");
	return -1;
    }
    memcpy(*buf, res->rf[0].file, *size);
    if(openedFiles->print) {
	printf("Letto il file: %s\n", res->rf[0].path);
	printf("Di dimensione: %ld B\n", *size);
	fflush(openedFiles->out);
    }
    if(openedFiles->rDir) {
	if(openedFiles->print) {
	    fprintf(openedFiles->out, "Il file letto e' stato scritto nella cartella: %s\n", openedFiles->rDir);
	    fflush(openedFiles->out);
	}
	if(storeFilesInDirectory(openedFiles->rDir, 1, res->rf) == -1) {
	    perror("readFile: storeFilesInDirectory");
	    freeResponse(res);
	    free(res);
	    free(cmd);
	    return -1;
	}
    } else {
	if(openedFiles->print) {
	    fprintf(openedFiles->out, "Il file letto non è stato memorizzato su disco\n");
	    fflush(openedFiles->out);
	}
    }

    freeResponse(res);
    free(res);

    free(cmd);

    return 0;
}

int readNFiles(int N, const char* dirname) {
    if(!dirname) {
	errno = EINVAL;
	return -1;
    }
    if(!openedFiles){
	errno = EPROTO;
	return -1;
    }
    if(openedFiles->createdAndLocked)
	free(openedFiles->createdAndLocked);
    openedFiles->createdAndLocked = NULL;

    if(strcmp(socketName, "") == 0) {
	errno = ENOTCONN;
	return -1;
    }

    /* send to server the string "readNFiles|$(N)" */
    int lenght_n = snprintf(NULL, 0, "%d", N);
    long len = strlen("readNFiles")+1+lenght_n+1;
    char *cmd = malloc(len);
    if(!cmd) {
	perror("readNFiles: malloc");
	return -1;
    }
    memset(cmd, 0, len);
    snprintf(cmd, len, "readNFiles|%d", N);
    len = strnlen(cmd, len);

    /* send cmd */
    if (writen(fd_skt, &len, sizeof(long)) == -1) {
	/* writen sets errno */
	free(cmd);
	return -1;
    }
    if (writen(fd_skt, cmd, len) == -1) {
	/* writen sets errno */
	free(cmd);
	return -1;
    }

    /* recive response */
    response_t *res = calloc(1, sizeof(response_t));
    if(!res){
	perror("readNFiles: calloc");
	free(cmd);
	return -1;
    }

    /* reciveData(, 1) because if we get a MEOK we expect N files */
    if(reciveData(res, 1) < 0) {
	/* errno is set by reciveData */
	freeResponse(res);
	free(res);
	free(cmd);
	return -1;
    }
    if(res->meerrno != 0) { /* errno from server */
	freeResponse(res);
	errno = res->meerrno;
	free(res);
	free(cmd);
	return -1;
    }

    if(openedFiles->print){
	for(int i=0;i<res->numfiles;++i) {
	    fprintf(openedFiles->out, "%d) %s\n", i, res->rf[i].path);
	}
	fflush(openedFiles->out);
    }

    /* save files to directory */
    if(storeFilesInDirectory(dirname, res->numfiles, res->rf) == -1) {
	perror("readNFiles: storeFilesindirectory");
	freeResponse(res);
	free(res);
	free(cmd);
	return -1;
    }

    int n = res->numfiles;

    freeResponse(res);
    free(res);

    free(cmd);
    return n;
}

int writeFile(const char* pathname, const char* dirname) {
    if(!pathname) {
	errno = EINVAL;
	return -1;
    }
    if(!openedFiles){
	errno = EPROTO;
	return -1;
    }
    if (strcmp(openedFiles->createdAndLocked, pathname) != 0) {
	errno = EPERM;
	return -1;
    }
    if(openedFiles->createdAndLocked)
	free(openedFiles->createdAndLocked);
    openedFiles->createdAndLocked = NULL;

    if(strcmp(socketName, "") == 0) {
	errno = ENOTCONN;
	return -1;
    }

    /* read the file that needs to be sent to the server */
    int fdi = -1;
    size_t lung = 0;
    size_t incr = 0;
    size_t size = 0;

    if ((fdi = open(pathname, O_RDONLY)) == -1) {
	perror("writeFile: open");
	return -1;
    }

    /* get file length */
    struct stat sb;
    if (fstat(fdi, &sb) == -1) {
	perror("writeFile: fstat");
	return -1;
    }
    lung = sb.st_size;

    void *content = malloc(lung);
    if(!content) {
	perror("writeFile: malloc");
	return -1;
    }

    /* read file */
    while ((incr = read(fdi, content, lung)) > 0) {
	size += incr;
	lung -= incr;
    }

    if (incr == -1) {
	free(content);
	return -1;
    }

    if (openedFiles->print) {
	fprintf(openedFiles->out, "Dimensione: %ldB ", size);
	fflush(openedFiles->out);
    }

    if (close(fdi) == -1) {
	perror("writeFile: close");
	free(content);
	return -1;
    }

    /* send to server the string "writeFile|$(pathname)|$(size)" */
    int leng_size = snprintf(NULL, 0, "%zu", size);
    long len = strlen("writeFile")+1+strlen(pathname)+1+leng_size+1;
    char *cmd = calloc(len, sizeof(char));
    if(!cmd) {
	perror("writeFile: calloc");
	free(content);
	return -1;
    }
    snprintf(cmd, len, "writeFile|%s|%zu", pathname, size);
    len = strnlen(cmd, len);

    /* send cmd */
    if (writen(fd_skt, &len, sizeof(long)) == -1) {
	/* writen sets errno */
	free(content);
	free(cmd);
	return -1;
    }
    if (writen(fd_skt, cmd, len) == -1) {
	/* writen sets errno */
	free(content);
	free(cmd);
	return -1;
    }

    /* recive response */
    response_t *res = calloc(1, sizeof(response_t));
    if(!res){
	perror("writeFile: calloc");
	free(content);
	free(cmd);
	return -1;
    }

    /* reciveData(, 0) because if we get a MEOK we don't expect files */
    if(reciveData(res, 0) < 0) {
	/* errno is set by reciveData */
	freeResponse(res);
	free(res);
	free(cmd);
	free(content);
	return -1;
    }
    if(res->meerrno != 0) {
	/* errno from server */
	freeResponse(res);
	errno = res->meerrno;
	free(res);
	free(cmd);
	free(content);
	return -1;
    }
    if(strncmp(res->ME, MEFP, sizeof(res->ME)) == 0) {
	/* some files were purged */
	if(openedFiles->print){
	    fprintf(openedFiles->out, "Il server ha espulso i seguenti file:\n");
	    fflush(openedFiles->out);
	    for(int i=0;i<res->numfiles;++i) {
		fprintf(openedFiles->out, "%d) %s\n", i, res->rf[i].path);
	    }
	}
	if(dirname) {
	    if(storeFilesInDirectory(dirname, res->numfiles, res->rf) == -1) {
		perror("writeFile: storeFilesindirectory");
		freeResponse(res);
		free(res);
		free(content);
		free(cmd);
		return -1;
	    }
	    if(openedFiles->print) {
		fprintf(openedFiles->out, "I file espulsi sono stati scritti nella cartella: %s\n", dirname);
		fflush(openedFiles->out);
	    }
	} else {
	    if(openedFiles->print) {
		fprintf(openedFiles->out, "I file espulsi non sono stati memorizzati su disco\n");
		fflush(openedFiles->out);
	    }
	}
    }

    /* send file to server */
    if (writen(fd_skt, content, size) == -1) {
	/* errno set by writen */
	freeResponse(res);
	free(res);
	free(cmd);
	free(content);
	return -1;
    }


    /* reciveData(, 0) because if we get a MEOK we don't expect files */
    if(reciveData(res, 0) < 0) {
	/* errno is set by reciveData */
	freeResponse(res);
	free(res);
	free(cmd);
	free(content);
	return -1;
    }
    if(res->meerrno != 0) { /* errno from server */
	freeResponse(res);
	errno = res->meerrno;
	free(res);
	free(cmd);
	free(content);
	return -1;
    }

    freeResponse(res);
    free(res);

    free(cmd);

    free(content);
    return 0;
}

int appendToFile(const char* pathname, void* buf, size_t size, const char* dirname) {
    if(!pathname || !buf) {
	errno = EINVAL;
	return -1;
    }
    if(!openedFiles){
	errno = EPROTO;
	return -1;
    }
    if(openedFiles->createdAndLocked)
	free(openedFiles->createdAndLocked);
    openedFiles->createdAndLocked = NULL;

    if(strcmp(socketName, "") == 0) {
	errno = ENOTCONN;
	return -1;
    }

    if (isOpen(pathname, 0) != 1) {
	errno = EPERM;
	return -1;
    }

    if (openedFiles->print) {
	fprintf(openedFiles->out, "Dimensione: %ld B\n", size);
	fflush(openedFiles->out);
    }

    /* send to server the string "appendToFile|$(pathname)|$(size)" */
    int leng_size = snprintf(NULL, 0, "%zu", size);
    long len = strlen("appendToFile")+1+strlen(pathname)+1+leng_size+1;
    char *cmd = malloc(len);
    if(!cmd) {
	perror("appendToFile: malloc");
	return -1;
    }
    memset(cmd, 0, len);
    snprintf(cmd, len, "appendToFile|%s|%zu", pathname, size);

    /* send cmd */
    if (writen(fd_skt, &len, sizeof(long)) == -1) {
	/* writen sets errno */
	free(cmd);
	return -1;
    }
    if (writen(fd_skt, cmd, len) == -1) {
	/* writen sets errno */
	free(cmd);
	return -1;
    }

    /* recive response */
    response_t *res = calloc(1, sizeof(response_t));
    if(!res){
	perror("appendToFile: calloc");
	free(cmd);
	return -1;
    }

    /* reciveData(, 0) because if we get a MEOK we don't expect files */
    if(reciveData(res, 0) < 0) {
	/* errno is set by reciveData */
	freeResponse(res);
	free(res);
	free(cmd);
	return -1;
    }

    if(res->meerrno != 0) { /* errno from server */
	freeResponse(res);
	errno = res->meerrno;
	free(res);
	free(cmd);
	return -1;
    }

    if(strncmp(res->ME, MEFP, sizeof(res->ME)) == 0) {
	/* some files were purged */
	if(openedFiles->print){
	    fprintf(openedFiles->out, "Il server ha espulso i seguenti file:\n");
	    fflush(openedFiles->out);
	    for(int i=0;i<res->numfiles;++i) {
		fprintf(openedFiles->out, "%d) %s\n", i, res->rf[i].path);
	    }
	}
	if(dirname) {
	    if(storeFilesInDirectory(dirname, res->numfiles, res->rf) == -1) {
		perror("appendToFile: storeFilesindirectory");
		freeResponse(res);
		free(res);
		free(cmd);
		return -1;
	    }
	    if(openedFiles->print) {
		fprintf(openedFiles->out, "I file espulsi sono stati scritti nella cartella: %s\n", dirname);
		fflush(openedFiles->out);
	    }
	} else {
	    if(openedFiles->print) {
		fprintf(openedFiles->out, "I file espulsi non sono stati memorizzati su disco\n");
		fflush(openedFiles->out);
	    }
	}
    }

    /* send file to server */
    if (writen(fd_skt, buf, size) == -1) {
	/* errno set by writen */
	freeResponse(res);
	free(res);
	free(cmd);
	return -1;
    }

    freeResponse(res);
    free(res);
    free(cmd);

    return 0;
}

int lockFile(const char* pathname) {
    if(!pathname){
	errno = EINVAL;
	return -1;
    }
    if(!openedFiles){
	errno = EPROTO;
	return -1;
    }
    if(openedFiles->createdAndLocked)
	free(openedFiles->createdAndLocked);
    openedFiles->createdAndLocked = NULL;

    if(strcmp(socketName, "") == 0) {
	errno = ENOTCONN;
	return -1;
    }

    if(isOpen(pathname, O_LOCK)){ /* file is already locked */
	return 0;
    }

    int existing = 0;
    if(isOpen(pathname, 0)){ /* file is already open */
	existing = 1;
	goto _unlockFile;
    }

    if (openFile(pathname, O_LOCK) == 0) /* open the file with the lock */
	return 0;

    if (errno == ENOENT) /* file created but not locked */
	goto _unlockFile;

    return -1; /* errno != ENOENT */

_unlockFile: {
	/* send to server the string "lockFile|$(pathname)" */
	long len = strlen("lockFile")+1+strlen(pathname)+1;
	char *cmd = malloc(len);
	if(!cmd) {
	    perror("lockFile: malloc");
	    return -1;
	}
	memset(cmd, 0, len);
	snprintf(cmd, len, "lockFile|%s", pathname);

	/* send cmd */
	if (writen(fd_skt, &len, sizeof(long)) == -1) {
	    /* writen sets errno */
	    free(cmd);
	    return -1;
	}
	if (writen(fd_skt, cmd, len) == -1) {
	    /* writen sets errno */
	    free(cmd);
	    return -1;
	}

	/* recive response */
	response_t *res = calloc(1, sizeof(response_t));
	if(!res){
	    perror("lockFile: calloc");
	    free(cmd);
	    return -1;
	}

	/* reciveData(, 0) because if we get a MEOK we dont expect a file */
	if(reciveData(res, 0) < 0) {
	    /* errno is set by reciveData */
	    freeResponse(res);
	    free(res);
	    free(cmd);
	    return -1;
	}
	if(res->meerrno != 0) {
	    /* errno from server */
	    freeResponse(res);
	    errno = res->meerrno;
	    free(res);
	    free(cmd);
	    return -1;
	}

	if(!existing) {
	    if(addOpenFile(pathname, O_LOCK) == -1) {
		perror("lockFile: addOpenFile");
		freeResponse(res);
		free(res);
		free(cmd);
		return -1;
	    }
	}

	freeResponse(res);
	free(res);
	free(cmd);
	return 0;
    }
}

int unlockFile(const char* pathname) {
    if(!pathname){
	errno = EINVAL;
	return -1;
    }
    if(!openedFiles){
	errno = EPROTO;
	return -1;
    }
    if(openedFiles->createdAndLocked)
	free(openedFiles->createdAndLocked);
    openedFiles->createdAndLocked = NULL;

    if(strcmp(socketName, "") == 0) {
	errno = ENOTCONN;
	return -1;
    }
    if(isOpen(pathname, 0) != 1) { /* not open or not locked */
	errno = EPERM;
	return -1;
    }

    /* send to server the string "unlockFile|$(pathname)" */
    long len = strlen("unlockFile")+1+strlen(pathname)+1;
    char *cmd = malloc(len);
    if(!cmd) {
	perror("unlockFile: malloc");
	return -1;
    }
    memset(cmd, 0, len);
    snprintf(cmd, len, "unlockFile|%s", pathname);

    /* send cmd */
    if (writen(fd_skt, &len, sizeof(long)) == -1) {
	/* writen sets errno */
	free(cmd);
	return -1;
    }
    if (writen(fd_skt, cmd, len) == -1) {
	/* writen sets errno */
	free(cmd);
	return -1;
    }

    /* recive response */
    response_t *res = calloc(1, sizeof(response_t));
    if(!res){
	perror("unlockFile: calloc");
	free(cmd);
	return -1;
    }

    /* reciveData(, 0) because if we get a MEOK we dont expect a file */
    if(reciveData(res, 0) < 0) {
	/* errno is set by reciveData */
	freeResponse(res);
	free(res);
	free(cmd);
	return -1;
    }
    if(res->meerrno != 0) {
	/* errno from server */
	freeResponse(res);
	errno = res->meerrno;
	free(res);
	free(cmd);
	return -1;
    }

    freeResponse(res);
    free(res);
    free(cmd);
    return 0;
}

int closeFile(const char *pathname) {
    if(!pathname){
	errno = EINVAL;
	return -1;
    }
    if(!openedFiles){
	errno = EPROTO;
	return -1;
    }
    if(openedFiles->createdAndLocked)
	free(openedFiles->createdAndLocked);
    openedFiles->createdAndLocked = NULL;

    if(strcmp(socketName, "") == 0) {
	errno = ENOTCONN;
	return -1;
    }

    if(isOpen(pathname, 0) != 1) { /* not open */
	errno = EPERM;
	return -1;
    }

    /* invio al server la stringa "closeFile|$(pathname)" */
    long len = strlen("closeFile")+1+strlen(pathname)+1;
    char *cmd = malloc(len);
    if(!cmd) {
	perror("closeFile: malloc");
	return -1;
    }
    memset(cmd, 0, len);
    snprintf(cmd, len, "closeFile|%s", pathname);

    /* send cmd */
    if (writen(fd_skt, &len, sizeof(long)) == -1) {
	/* writen sets errno */
	free(cmd);
	return -1;
    }
    if (writen(fd_skt, cmd, len) == -1) {
	/* writen sets errno */
	free(cmd);
	return -1;
    }

    /* recive response */
    response_t *res = calloc(1, sizeof(response_t));
    if(!res){
	perror("closeFile: calloc");
	free(cmd);
	return -1;
    }

    /* reciveData(, 0) because if we get a MEOK we dont expect a file */
    if(reciveData(res, 0) < 0) {
	/* errno is set by reciveData */
	freeResponse(res);
	free(res);
	free(cmd);
	return -1;
    }
    if(res->meerrno != 0) {
	/* errno from server */
	freeResponse(res);
	errno = res->meerrno;
	free(res);
	free(cmd);
	return -1;
    }

    if (removeOpenFile(pathname) == -1) {
	perror("closeFile: removeOpenFile");
    } else {
	openedFiles->numOfFiles--;
    }

    freeResponse(res);
    free(res);
    free(cmd);

    return 0;
}

int removeFile(const char* pathname) {
    if(!pathname){
	errno = EINVAL;
	return -1;
    }
    if(!openedFiles){
	errno = EPROTO;
	return -1;
    }
    if(openedFiles->createdAndLocked)
	free(openedFiles->createdAndLocked);
    openedFiles->createdAndLocked = NULL;

    if(strcmp(socketName, "") == 0) {
	errno = ENOTCONN;
	return -1;
    }

    if (isOpen(pathname, 0) != 1) { /* not open */
	errno = EPERM;
	return -1;
    }

    /* send to server the string "removeFile|$(pathname)" */
    long len = strlen("removeFile")+1+strlen(pathname)+1;
    char *cmd = malloc(len);
    if(!cmd) {
	perror("removeFile: malloc");
	return -1;
    }
    memset(cmd, 0, len);
    snprintf(cmd, len, "removeFile|%s", pathname);

    /* send cmd */
    if (writen(fd_skt, &len, sizeof(long)) == -1) {
	/* writen sets errno */
	free(cmd);
	return -1;
    }
    if (writen(fd_skt, cmd, len) == -1) {
	/* writen sets errno */
	free(cmd);
	return -1;
    }

    /* recive response */
    response_t *res = calloc(1, sizeof(response_t));
    if(!res){
	perror("removeFile: calloc");
	free(cmd);
	return -1;
    }

    /* reciveData(, 0) because if we get a MEOK we dont expect a file */
    if(reciveData(res, 0) < 0) {
	/* errno is set by reciveData */
	freeResponse(res);
	free(res);
	free(cmd);
	return -1;
    }
    if(res->meerrno != 0) {
	/* errno from server */
	freeResponse(res);
	errno = res->meerrno;
	free(res);
	free(cmd);
	return -1;
    }

    if (removeOpenFile(pathname) == -1) {
	perror("removeFile: removeOpenFile");
    } else {
	openedFiles->numOfFiles--;
    }
    freeResponse(res);
    free(res);
    free(cmd);
    return 0;
}

// -----------------------------------------------------------------------------
int setDirectory(char* Dir, int rw) {
    if (!Dir) {
	errno = EINVAL;
	return -1;
    }

    if (rw == 1) {
	if(openedFiles->validwDir) {
	    free(openedFiles->wDir);
	    openedFiles->wDir = NULL;
	    openedFiles->validwDir = 0;
	}
	if(strncmp(Dir, "/dev/null", strlen("/dev/null")+1) == 0) {
	    return 0;
	}
	openedFiles->validwDir = 1;
	openedFiles->wDir = malloc(strlen(Dir)+1);
	strncpy(openedFiles->wDir, Dir, strlen(Dir)+1);
    } else {
	if(openedFiles->validrDir) {
	    free(openedFiles->rDir);
	    openedFiles->rDir = NULL;
	    openedFiles->validrDir = 0;
	}
	if(strncmp(Dir, "/dev/null", strlen("/dev/null")+1) == 0) {
	    return 0;
	}
	openedFiles->validrDir = 1;
	openedFiles->rDir = malloc(strlen(Dir)+1);
	strncpy(openedFiles->rDir, Dir, strlen(Dir)+1);
    }
    return 0;
}

void printInfo(int p, FILE *stream) {
    /* 1 prints, 0 does not print */
    if(!openedFiles) {
	if(createOpenedFiles()<0) {
	    perror("printInfo: createOpenedfiles");
	    return;
	}
    }
    openedFiles->print = (p)? 1: 0;
    openedFiles->out = stream;
    return;
}

// -----------------------------------------------------------------------------
// helper functions

int reciveData(response_t *res, int expected) {
    if(!res) {
	errno = EINVAL;
	return -1;
    }

    int readnres;
    readnres = readn(fd_skt, &res->ME, sizeof(res->ME));
    if(readnres <= 0) {
	/* readn sets errno */
	return -1;
    }

    if(expected == 0) /* no file expected */
	goto _nofile;


    /* file is expected */
    if(strncmp(res->ME, MEOK, sizeof(res->ME))==0){
	/* ok response */
	res->meerrno = 0;
	/* get number of files sent */
	readnres = readn(fd_skt, &res->numfiles, sizeof(int64_t));
	if(readnres<=0) /* readn sets errno */
	    return -1;

	if(res->rf)
	    free(res->rf);

	if(res->numfiles < 0) {
	    errno = EINVAL;
	    return -1;
	}

	res->rf = calloc(res->numfiles, sizeof(recivedFile_t));
	if(!res->rf){
	    perror("reciveData: calloc");
	    return -1;
	}

	/* get files */
	for(int i=0;i<res->numfiles;++i) {
	    /* read path */
	    readnres = readn(fd_skt, &res->rf[i].pathlen, sizeof(int64_t));
	    if(readnres<=0) /* readn sets errno */
		return -1;
	    res->rf[i].path = calloc(res->rf[i].pathlen, sizeof(char));
	    if(!res->rf[i].path){
		perror("reciveData: calloc");
		return -1;
	    }
	    readnres = readn(fd_skt, res->rf[i].path, res->rf[i].pathlen);
	    if(readnres<=0) /* readn sets errno */
		return -1;

	    /* we replace '/' char with '-' */
	    for(int j=0;j<res->rf[i].pathlen; ++j){
		if(res->rf[i].path[j] == '/')
		    res->rf[i].path[j] = '-';
	    }

	    /* read file */
	    readnres = readn(fd_skt, &res->rf[i].filelen, sizeof(int64_t));
	    if(readnres<=0) /* readn sets errno */
		return -1;

	    if(res->rf[i].filelen == 0) {
		res->rf[i].file = calloc(1, sizeof(char));
		if(!res->rf[i].file){
		    perror("reciveData: calloc");
		    return -1;
		}
		continue;
	    }

	    res->rf[i].file = calloc(res->rf[i].filelen, sizeof(char));
	    if(!res->rf[i].file){
		perror("reciveData: calloc");
		return -1;
	    }
	    readnres = readn(fd_skt, res->rf[i].file, res->rf[i].filelen);
	    if(readnres<=0) {/* readn sets errno */
		return -1;
	    }
	}
	return 0;
    }
    if(strncmp(res->ME, MEFP, sizeof(res->ME))==0){
	/* file purged */
	res->meerrno = 0;
	/* get number of files sent */
	readnres = readn(fd_skt, &res->numfiles, sizeof(int));
	if(readnres<=0) /* readn sets errno */
	    return -1;
	if(res->rf)
	    free(res->rf);
	res->rf = calloc(res->numfiles, sizeof(recivedFile_t));
	if(!res->rf){
	    perror("reciveData: calloc");
	    return -1;
	}

	/* get files */
	for(int i=0;i<res->numfiles;++i) {
	    /* read path */
	    readnres = readn(fd_skt, &res->rf[i].pathlen, sizeof(int64_t));
	    if(readnres<=0) /* readn sets errno */
		return -1;
	    res->rf[i].path = calloc(res->rf[i].pathlen, sizeof(char));
	    if(!res->rf[i].path){
		perror("reciveData: calloc");
		return -1;
	    }
	    readnres = readn(fd_skt, res->rf[i].path, res->rf[i].pathlen);
	    if(readnres<=0) /* readn sets errno */
		return -1;

	    /* we replace '/' char with '-' */
	    for(int j=0;j<res->rf[i].pathlen; ++j){
		if(res->rf[i].path[j] == '/')
		    res->rf[i].path[j] = '-';
	    }

	    /* read file */
	    readnres = readn(fd_skt, &res->rf[i].filelen, sizeof(int64_t));
	    if(readnres<=0) /* readn sets errno */
		return -1;

	    if(res->rf[i].filelen == 0) {
		res->rf[i].file = calloc(1, sizeof(char));
		if(!res->rf[i].file){
		    perror("reciveData: calloc");
		    return -1;
		}
		continue;
	    }

	    res->rf[i].file = calloc(res->rf[i].filelen, sizeof(char));
	    if(!res->rf[i].file){
		perror("reciveData: calloc");
		return -1;
	    }
	    readnres = readn(fd_skt, res->rf[i].file, res->rf[i].filelen);
	    if(readnres<=0) /* readn sets errno */
		return -1;
	}
	return 0;
    }
    if(strncmp(res->ME, MESD, sizeof(res->ME))==0){
	/* server shutting down */
	readnres = readn(fd_skt, &res->meerrno, sizeof(errno));
	if(readnres <= 0)/* readn sets errno */
	    return -1;
	return 0;
    }
    if(strncmp(res->ME, MENT, sizeof(res->ME))==0){
	/* requested file action not taken */
	readnres = readn(fd_skt, &res->meerrno, sizeof(errno));
	if(readnres <= 0)/* readn sets errno */
	    return -1;
	return 0;
    }
    if(strncmp(res->ME, MESY, sizeof(res->ME))==0){
	/* syntax error */
	readnres = readn(fd_skt, &res->meerrno, sizeof(errno));
	if(readnres <= 0)/* readn sets errno */
	    return -1;
	return 0;
    }
    if(strncmp(res->ME, MESE, sizeof(res->ME))==0){
	/* server error */
	readnres = readn(fd_skt, &res->meerrno, sizeof(errno));
	if(readnres <= 0)/* readn sets errno */
	    return -1;
	return 0;
    }

    errno = ENOPROTOOPT;
    return -2;

_nofile:
    res->numfiles = 0;
    if(res->rf)
	free(res->rf);
    res->rf = NULL;

    if(strncmp(res->ME, MEOK, sizeof(res->ME))==0){
	/* simple ok response */
	res->meerrno = 0;
	return 0;
    }
    if(strncmp(res->ME, MEFP, sizeof(res->ME))==0){
	/* file purged */
	res->meerrno = 0;
	/* get number of files sent */
	readnres = readn(fd_skt, &res->numfiles, sizeof(int64_t));
	if(readnres<=0) /* readn sets errno */
	    return -1;


	if(res->rf)
	    free(res->rf);
	res->rf = calloc(res->numfiles, sizeof(recivedFile_t));
	if(!res->rf){
	    perror("reciveData: calloc");
	    return -1;
	}
	/* get files */
	for(int i=0;i<res->numfiles;++i) {
	    /* read path */
	    readnres = readn(fd_skt, &res->rf[i].pathlen, sizeof(int64_t));
	    if(readnres<=0) /* readn sets errno */
		return -1;
	    res->rf[i].path = calloc(res->rf[i].pathlen, sizeof(char));
	    if(!res->rf[i].path){
		perror("reciveData: calloc");
		return -1;
	    }
	    readnres = readn(fd_skt, res->rf[i].path, res->rf[i].pathlen);
	    if(readnres<=0) /* readn sets errno */
		return -1;

	    /* we replace '/' char with '-' */
	    for(int j=0;j<res->rf[i].pathlen; ++j){
		if(res->rf[i].path[j] == '/')
		    res->rf[i].path[j] = '-';
	    }

	    /* read file */
	    readnres = readn(fd_skt, &res->rf[i].filelen, sizeof(int64_t));
	    if(readnres<=0) /* readn sets errno */
		return -1;

	    /* file has lenght 0 -> allocate memory but dont read */
	    if(res->rf[i].filelen == 0) {
		res->rf[i].file = calloc(1, sizeof(char));
		if(!res->rf[i].file){
		    perror("reciveData: calloc");
		    return -1;
		}
		continue;
	    }
	    res->rf[i].file = calloc(res->rf[i].filelen, sizeof(char));
	    if(!res->rf[i].file){
		perror("reciveData: calloc");
		return -1;
	    }
	    readnres = readn(fd_skt, res->rf[i].file, res->rf[i].filelen);
	    if(readnres<=0) /* readn sets errno */
		return -1;
	}
	return 0;
    }
    if(strncmp(res->ME, MESD, sizeof(res->ME))==0){
	/* server shutting down */
	readnres = readn(fd_skt, &res->meerrno, sizeof(errno));
	if(readnres <= 0)/* readn sets errno */
	    return -1;
	return 0;
    }
    if(strncmp(res->ME, MENT, sizeof(res->ME))==0){
	/* requested file action not taken */
	readnres = readn(fd_skt, &res->meerrno, sizeof(errno));
	if(readnres <= 0)/* readn sets errno */
	    return -1;
	return 0;
    }
    if(strncmp(res->ME, MESY, sizeof(res->ME))==0){
	/* syntax error */
	readnres = readn(fd_skt, &res->meerrno, sizeof(errno));
	if(readnres <= 0)/* readn sets errno */
	    return -1;
	return 0;
    }
    if(strncmp(res->ME, MESE, sizeof(res->ME))==0){
	/* server error */
	readnres = readn(fd_skt, &res->meerrno, sizeof(errno));
	if(readnres <= 0)/* readn sets errno */
	    return -1;
	return 0;
    }

    errno = ENOPROTOOPT;
    return -2;
}

int storeFilesInDirectory(const char *dirname, int n, recivedFile_t *rf) {
    if(!dirname || strcmp(dirname, "")==0 || !rf || n<0) {
	errno = EINVAL;
	return -1;
    }

    /* create directory */
    if(mkdir(dirname, 0777) == -1) {
	if(errno != EEXIST) { /* unknown error */
	    return -1;
	}
    }

    size_t basepathlen = strlen(dirname)+1+1; /* +1 for '/' and +1 for '\0' */
    char *basepath = calloc(basepathlen, sizeof(char));
    if(!basepath) {
	perror("storeFilesInDirectory: calloc");
	return -1;
    }
    strcpy(basepath, dirname);
    strncat(basepath, "/", basepathlen);

    /* for each file, create and write */
    for(int i=0;i<n;++i) {
	char *filename = calloc(basepathlen + rf[i].pathlen, sizeof(char));
	if(!filename){
	    perror("storeFilesInDirectory: calloc");
	    free(basepath);
	    return -1;
	}
	strcpy(filename, basepath);
	strncat(filename, rf[i].path, basepathlen + rf[i].pathlen);

	int fdo;
	if((fdo = open(filename, O_WRONLY | O_CREAT, 0666)) == -1) { /* open */
	    free(filename);
	    free(basepath);
	    return -1;
	}

	if(write(fdo, rf[i].file, rf[i].filelen) == -1) { /* write */
	    free(filename);
	    free(basepath);
	    return -1;
	}

	if(close(fdo) == -1) { /* close */
	    free(filename);
	    free(basepath);
	    return -1;
	}

	free(filename);
    }

    free(basepath);
    return 0;
}

void freeResponse(response_t *res) {
    if(!res)
	return;
    if(res->numfiles>0 && res->rf){
	for(int i=0;i<res->numfiles;++i){
	    if(res->rf[i].path)
		free(res->rf[i].path);
	    res->rf[i].path = NULL;
	    if(res->rf[i].file)
		free(res->rf[i].file);
	    res->rf[i].file = NULL;
	}
	free(res->rf);
    }
    return;
}

int isOpen(const char *pathname, const int flags) {
    if(!pathname) {
	errno = EINVAL;
	return -1;
    }

    if (openedFiles == NULL || openedFiles->f == NULL || openedFiles->numOfFiles == 0) {
	return 0;
    }

    files_t *tmp = openedFiles->f;
    while(tmp) {
	if(strcmp(tmp->filename, pathname) == 0 && (tmp->locked || !(flags&O_LOCK)))
	    return 1;
	tmp = tmp->next;
    }

    return 0;
}

int addOpenFile(const char *pathname, const int flags) {
    if(!pathname) {
	errno = EINVAL;
	return -1;
    }

    files_t *new = malloc(sizeof(files_t));
    if(!new) {
	perror("addOpenFile: malloc");
	return -1;
    }

    size_t len = strlen(pathname)+1;
    new->locked = flags&O_LOCK;
    new->filename = calloc(len, sizeof(char));
    if(!new->filename) {
	perror("addOpenFile: calloc");
	free(new);
	return -1;
    }

    strncpy(new->filename, pathname, len);
    new->next = NULL;

    if(openedFiles->f == NULL) {
	openedFiles->f = new;
	openedFiles->numOfFiles = 1;
	return 0;
    }

    files_t *tail = openedFiles->f;
    while(tail->next) {
	tail = tail->next;
    }
    tail->next = new;
    openedFiles->numOfFiles++;
    return 0;
}

int removeOpenFile(const char *pathname) {
    if(!pathname) {
	errno = EINVAL;
	return -1;
    }

    if(!openedFiles || !openedFiles->f || openedFiles->numOfFiles == 0) {
	errno = ENOENT;
	return -1;
    }

    files_t *tmp = openedFiles->f;

    /* the element to remove is the first */
    if(strcmp(tmp->filename, pathname) == 0) {
	openedFiles->f = tmp->next;
	free(tmp->filename);
	free(tmp);
	return 0;
    }

    files_t *prc = NULL;

    while(tmp->next) {
	prc = tmp;
	tmp = tmp->next;
	if(strcmp(tmp->filename, pathname) == 0) {
	    prc->next = tmp->next;
	    free(tmp->filename);
	    free(tmp);
	    return 0;
	}
    }

    /* file not found */
    errno = ENOENT;
    return -1;
}

int closeEveryFile() {
    if (openedFiles == NULL)
	return 0;

    if (openedFiles->numOfFiles > 0 && openedFiles->f != NULL) {
	files_t *tmp = openedFiles->f;
	files_t *prc = NULL;
	while(tmp){
	    prc = tmp;
	    tmp = tmp->next;

	    if(closeFile(prc->filename) != 0) {
		if(removeOpenFile(prc->filename) != 0) {
		    perror("closeEveryFile: removeOpenfile");
		}
		openedFiles->numOfFiles--;
	    }
	}
    }

    if(openedFiles->createdAndLocked) {
	free(openedFiles->createdAndLocked);
	openedFiles->createdAndLocked = NULL;
    }
    if(openedFiles->validrDir) {
	free(openedFiles->rDir);
	openedFiles->validrDir = 0;
	openedFiles->rDir = NULL;
    }
    if(openedFiles->validwDir) {
	free(openedFiles->wDir);
	openedFiles->validwDir = 0;
	openedFiles->wDir = NULL;
    }

    free(openedFiles);
    openedFiles = NULL;
    return 0;
}

int createOpenedFiles() {
    openedFiles = calloc(1, sizeof(*openedFiles));
    if(!openedFiles) {
	perror("createOpenedFiles: calloc");
	return -1;
    }
    openedFiles->f = NULL;
    openedFiles->numOfFiles = 0;
    openedFiles->createdAndLocked = NULL;
    openedFiles->validrDir = 0;
    openedFiles->rDir = NULL;
    openedFiles->validwDir = 0;
    openedFiles->wDir = NULL;
    openedFiles->print = 0;
    openedFiles->out = NULL;
    return 0;
}