/**
 * @file shared.c
 * @author syxhe (https://t.me/syxhe)
 * @brief *Implementing `shared.h`*
 * @version 0.1
 * @date 2025-06-09
 * 
 * @copyright Copyright (c) 2025
 * 
 */

#include "shared.h"

#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#include <error.h>

int rwbuf(char **str, unsigned long int initsize, int fd) {
	// Try to read bytes from fd into str
		// Bytes read == 0, return 0
		// Bytes read < 0, free string, return -1;
	// When string hits capacity, double the capacity, and reallocate the string
	if(!str || initsize < 1) ERRRET(EINVAL, -1);
	const int ECODE = -100;

	char *lstr = NULL, *tmp = NULL;
	ssize_t bytesread = -1;
	int csize = initsize, ccap = initsize;

	lstr = calloc(initsize, sizeof(char));
	if(!lstr)
		return -1;
	
	while((bytesread = read(fd, lstr + (csize - ccap), ccap)) > 0) {
		ccap -= bytesread;
		if(ccap <= 0) {
			csize *= 2;
			ccap = csize / 2;

			tmp = realloc(lstr, csize * sizeof(char));
			if(!tmp) {
                if(___VXGG___VERBOSE_ERRORS___)
				    error(0, errno, "Could not reallocate enough space for lstr");
                
				free(lstr);
                lstr = NULL; // Need to set this because of the break
				bytesread = ECODE;
				break;
			}
			lstr = tmp;
		}
	}
	if(bytesread < 0 && bytesread != ECODE) {
        if(___VXGG___VERBOSE_ERRORS___)
		    error(0, errno, "Ran into a read() error");

		free(lstr);
		lstr = NULL;
	}

	if(lstr) {
		tmp = realloc(lstr, csize - ccap + 1);
		if(!tmp) {
            if(___VXGG___VERBOSE_ERRORS___)
			    error(0, errno, "Could not shrink lstr after reading buffer");

			free(lstr);
			bytesread = ECODE;
		}
		lstr = tmp;
	}

    if(lstr && fd == STDIN_FILENO) {
        lstr[csize - ccap - 1] = '\0'; // Don't include the newline
    }

	*str = lstr;
	return ((bytesread == 0) ? (csize - ccap) : -1);
}


int wwbuf(int fd, const unsigned char *buf, int len) {
	if(!buf || len <= 0) ERRRET(EINVAL, -1);

    int total = 0;
    int left = len;
    int n = -1;

    while(total < len) {
        if((n = write(fd, buf + total, left)) < 0) 
            break;

        total += n;
        left -= n;
    }

    return (n < 0) ? -1 : 0;
}
// Adapted from Beej's `sendall()` function
// https://beej.us/guide/bgnet/html/split/slightly-advanced-techniques.html#sendall
    // Thanks Beej!

// dirname but less retarded hopefully
char * vxdirname(const char * const path) {
	char *tmp = NULL;
	if(!path) { // Path being null is a special case which should return early, before anything else (as to avoid null dereference)
		tmp = strdup(".");
		if(!tmp) {
			WARN(errno, "<vxdirname> could not strdup \".\" for set path result \"NULL\"", );
			return NULL;
		}

		return tmp;
	}

	unsigned char flag = 0;
	if(strcmp(path, ".") 	== 0) 			{tmp = strdup("."); flag++;}
	if(strcmp(path, "/") 	== 0 && !flag) 	{tmp = strdup("/"); flag++;}
	if(strcmp(path, "..") 	== 0 && !flag) 	{tmp = strdup("."); flag++;}

	if(flag) {
		if(!tmp) {
			WARN(errno, "<vxdirname> could not strdup a set path result", );
			return NULL;
		}

		return tmp;
	}


	/* From the manpages: (man 3 dirname)
	//		+=======================================+
	//		|	path		dirname		basename	|
	//		+=======================================+
	//		|	/usr/lib   	/usr      	lib			|
	//		|	/usr/      	/         	usr			|
	//		|	usr        	.         	usr			|
	//		+=======================================+
	*/

	// Get a temp copy of the path for manipulation purposes
	tmp = strdup(path);
	if(!tmp) {
		WARN(errno, "<vxdirname> could not strdup the given path \"%s\" for internal manipulation", , path);
		return NULL;
	}

	// If there's a trailing '/', delete it
	size_t pathlen = strlen(path);
	if(tmp[pathlen - 1] == '/') {
		tmp[pathlen - 1] = '\0';
		pathlen--;
	}

	// Ok, I think the easiest way to do this (if maybe a bit slow) is to count the number of '/'s in the string
		// If there's only one, return '/'
		// If there are 2 or more, find the last one in the list and set it to '\0'

	size_t count = 0;
	for(size_t i = 0; i < pathlen; i++) {
		if(tmp[i] == '/')
			count++;
	}

	if(count == 0 || count == 1)
		free(tmp);
	if(count == 0) {
		tmp = strdup(".");
		if(!tmp) {
			WARN(errno, "<xdirname> could not strdup \".\" for set path result", );
			return NULL;
		}
		return tmp;
	} else if(count == 1) {
		tmp = strdup("/");
		if(!tmp) {
			WARN(errno, "<xdirname> could not strdup \"/\" for set path result", );
			return NULL;
		}
		return tmp;
	}
	// This is retarded, fix it

	for(size_t i = 0, c2 = 0; i < pathlen; i++) {
		if(tmp[i] == '/')
			c2++;
		if(c2 == count)
			tmp[i] = '\0';
	}

	char * const actual = strdup(tmp);
	free(tmp);
	if(!actual) {
		WARN(errno, "<xdirname> could not strdup tmp string to make a shorter end string", );
		return NULL;
	}

	return actual;
}


int cleanup_init(cleanup *loc, fcallback callbacks[], void *arguments[], int size) {
    if(!loc || !callbacks || !arguments || size <= 0) ERRRET(EINVAL, -1);

    loc->callbacks = callbacks;
    loc->arguments = arguments;
    loc->size = size;
    loc->used = 0;

    return 0;
}

int cleanup_register(cleanup *loc, fcallback cb, void *arg) {
    if(!loc || !cb) ERRRET(EINVAL, -1);
    if(loc->used >= loc->size || loc->used < 0) ERRRET(ENOMEM, -1);

    loc->callbacks[loc->used] = cb;
    loc->arguments[loc->used] = arg;
    loc->used++;

    return 0;
}

// registers if flag is NOT set
int cleanup_cndregister(cleanup *loc, fcallback cb, void *arg, unsigned char flag) {
    if(flag) return 0;
    return cleanup_register(loc, cb, arg);
}

int cleanup_clear(cleanup *loc) {
    if(!loc) ERRRET(EINVAL, -1); 
    loc->used = 0;
    return 0;
}

int cleanup_fire(cleanup *loc) {
    if(!loc) ERRRET(EINVAL, -1);

    for(int i = (loc->used - 1); i >= 0; i--) {
        if(loc->callbacks[i] == NULL) {
            error(0, EINVAL, "cleanup_fire: refusing to run null callback...");
            continue;
        }

        loc->callbacks[i](loc->arguments[i]);
    }
    cleanup_clear(loc);

    return 0;
}

// Fires if flag is set
int cleanup_cndfire(cleanup *loc, unsigned char flag) {
    if(flag)
        return cleanup_fire(loc);
    return 0;
}