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

#include "fileutils.h"
#include "generic.h"

#define THRESHOLD 2000

int main(int argc, char ** argv) {
    int h, o, n, * index, * sizes, i, d;
    char temp[100];

    verbosity = M_INFO;

    if (argc != 2) {
	printm(M_BARE, "Usage: unarc <archive>\n");
	exit(-1);
    }
    
    if ((h = open(argv[1], O_RDONLY)) < 0) {
	printm(M_ERROR, "Unable to open archive file: %s\n", argv[1]);
	exit(-1);
    }
    
    read(h, &n, 4);
    
    printm(M_STATUS, "Archive claims to have %i files, checking integrity.\n", n);
    
    if (n > THRESHOLD) {
	printm(M_ERROR, "Archive has more than %i files, that doesn't make sense to me.\n", THRESHOLD);
	exit(-1);
    }
    
    index = (int *) malloc(n * sizeof(int));
    sizes = (int *) malloc(n * sizeof(int));
    
    for (i = 0; i < n; i++) {
	lseek(h, (i + 1) * 8 + 4, SEEK_SET);
	read(h, &(sizes[i]), 4);
	printm(M_INFO, "File #%i size = %i = 0x%08x\n", i, sizes[i], sizes[i]);
    }
    
    index[0] = (n + 1) * 8;
    i = 0;
    printm(M_INFO, "Index #%i = %i = 0x%08x\n", i, index[i], index[i]);
    
    for (i = 1; i < n; i++) {
	index[i] = index[i - 1] + sizes[i - 1];
	printm(M_INFO, "Index #%i = %i = 0x%08x\n", i, index[i], index[i]);
    }
    
    d = filesize(h) - index[n - 1] - sizes[n - 1];

    printm(M_INFO, "Archive size: %i, last index: %i, last file size: %i, difference = %i\n", filesize(h), index[n - 1], sizes[n - 1], d);
    
    if ((d < 0) || (d > 2048)) {
	printm(M_ERROR, "Archive incoherent.\n");
	exit(-1);
    }
    
    printm(M_STATUS, "Archive seems to be ok, extracting.\n");
    
    for (i = 0; i < n; i++) {
	sprintf(temp, "%04i.out", i);
	o = open(temp, O_WRONLY | O_CREAT | O_TRUNC, 0666);
	
	printm(M_INFO, "Extracting %s\n", temp);
	
	lseek(h, index[i], SEEK_SET);
	copy(h, o, sizes[i]);
	close(o);
    }
    
    exit(0);
}