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

#include "packages.h"

static struct package_record packages[MAX_PACKAGES];
static int max_packages = 0;
static int max_files = 0;
static int verbose = 0;

static struct {
	unsigned int packages;
	unsigned int packages_not_found;
} stats = {0, 0};

static char distro_name[DISTRO_NAME_LENGTH];

struct file_record {
	struct package_file_record pfr;
	struct file_record * next;
	int file_num;
	int duplicate;
} * file_base;


static struct file_record * add_filename(const char * filename,
    unsigned int package_num)
{
	struct file_record *new;

	new = malloc(sizeof(struct file_record));
	bzero(new, sizeof(*new));
	strncpy(new->pfr.filename, filename, FILENAME_LENGTH);
	new->pfr.package_num = package_num;
	new->pfr.tag_base = NULL;
	max_files++;
	new->file_num = max_files;

	new->next = file_base;
	file_base = new;

	return new;
}

int cmp_file(const void *a1, const void *b1)
{
	int n;
	struct file_record *a, *b;

	a = *(struct file_record **)a1;
	b = *(struct file_record **)b1;

	n = strcmp(a->pfr.filename, b->pfr.filename);

	/* Same file names, mark the later one found as duplicate */
	if (n == 0) {
		if (a->file_num < b->file_num) {
			b->duplicate = 1;
			n = -1;
		} else {
			a->duplicate = 1;
			n = 1;
		}
	}
	return(n);
}

void sort_filename(void)
{
	struct file_record **basepp, **bpp;
	struct file_record *frp;

	if (max_files <= 1)
		return;
	/* Create an array with all the filename records */
	basepp = malloc(max_files * sizeof(struct file_record *));
	for (frp = file_base, bpp = basepp; frp; bpp++, frp = frp->next)
		*bpp = frp;

	/*
	 * Sort them.  A side effect is that duplicate file
	 * names get marked as duplicate.
	 */
	qsort(basepp, max_files, sizeof(struct file_record *), cmp_file);

	/*
	 * Recreate the sorted list, starting from the end,
	 * skipping any duplicate entries.
	  */
	bpp = &basepp[max_files];
	file_base = NULL;

	while (bpp > basepp) {
		frp = *--bpp;
		if (frp->duplicate) {
			--max_files;
			continue;
		}
		frp->next = file_base;
		file_base = frp;
	}

	free(basepp);
}


static struct package_record * add_package(const char * package_name)
{
	struct package_record * new = &packages[max_packages];

	if (max_packages >= MAX_PACKAGES) {
		errx(1, "maximum number of packages (%d) was exceeded",
		    MAX_PACKAGES);
	}
	snprintf(new->package_name, PACKAGE_NAME_LENGTH, "%s", package_name);
	new->file_base = NULL;
	stats.packages++;
	max_packages++;

	return new;
}

static int load_distro(const char * list_dir)
{

	DIR *dirp;
	FILE * list_file;
	struct dirent *dp;
	char package_name[PACKAGE_NAME_LENGTH];
	char package_version[PACKAGE_VERSION_LENGTH];
	char package_release[PACKAGE_RELEASE_LENGTH];
	char package_arch[PACKAGE_ARCH_LENGTH];
	char filename[FILENAME_LENGTH];
	char path[FILENAME_LENGTH];
	char host_package [1024];
	struct package_record * pkg;
	char * c;
	FILE * pkg_file;
	char line[10240];
	int i;

	if ((dirp = opendir(list_dir)) == NULL) {
		perror("Opening distro dir");
		return -1;
	}
	while ((dp = readdir(dirp)) != NULL) {
		if ((c = strstr(dp->d_name, ".list")) == NULL)
			continue;

		snprintf(path, sizeof(path), "%s/%s", list_dir, dp->d_name);
		if ((list_file = fopen(path, "r")) == NULL) {
			perror("opening list file");
			continue;
		}
		
		snprintf(host_package, (c-dp->d_name)+1, "%s", dp->d_name);

		pkg = add_package(host_package);

		while (fgets(filename, sizeof(filename), list_file)) {
			filename[strlen(filename)-1] = '\0';
			add_filename(filename, max_packages-1);
		}

		fclose(list_file);

	}
	closedir(dirp);
	sort_filename();

	snprintf(filename, sizeof(filename), "%s/%s", list_dir, "distro");
	if ((pkg_file = fopen(filename, "r")) == NULL) {
		perror("Opening packages file");
		return -1;
	}
	fgets(distro_name, sizeof(distro_name), pkg_file);
	fclose(pkg_file);

	/*
	 * Open the file distro/packages and read to get the
	 * package/version/release/arch combos.  Note that we
	 * include the release, but ignore it.
	 */
	snprintf(filename, sizeof(filename), "%s/%s", list_dir, "packages");
	if ((pkg_file = fopen(filename, "r")) == NULL) {
		perror("Opening packages file");
		return -1;
	}

	while (fgets(line, sizeof(line), pkg_file)) {
		/* Format looks like: bsdutils 1:2.17.2-0ubuntu1 0 amd64 */
		if ((sscanf(line, "%s %s %s %s\n", package_name, package_version,
			package_release, package_arch)) == 4) {
			for (i = 0; i < max_packages; i++) {
				pkg = &packages[i];
				if (strcmp(pkg->package_name, package_name) == 0) {
					snprintf(pkg->package_version, 
						PACKAGE_VERSION_LENGTH,
						"%s", package_version);
					snprintf(pkg->package_arch, 
						PACKAGE_ARCH_LENGTH,
						"%s", package_arch);
					break;
				}
			}
			stats.packages_not_found++;
		}
	}
	fclose(pkg_file);


	return 0;
}

static int write_data(const char * filename) 
{

	FILE * fd;
	struct file_record * fr;

	if ((fd = fopen(filename, "w")) == NULL) {
		err(1, "%s", filename);
		/* NOT_REACHED */
	}

	if (fwrite(&distro_name, DISTRO_NAME_LENGTH, 1, fd) != 1 ||
	    fwrite(&max_packages, sizeof(max_packages), 1, fd) != 1 ||
	    fwrite(&max_files, sizeof(max_files), 1, fd) != 1 ||
	    fwrite(packages, sizeof(struct package_record),
					max_packages, fd) != max_packages)
		err(1, "fwrite()");

	for (fr = file_base; fr; fr = fr->next) {
		if (fwrite(&fr->pfr,
		    sizeof(struct package_file_record), 1, fd) != 1)
			err(1, "fwrite()");
	}
	fclose(fd);

	chmod(filename, S_IRUSR|S_IWUSR|S_IRGRP|S_IROTH);

	if (verbose) {
		printf("Distro: %s\n", distro_name);
		printf("Max packages: %d\n", max_packages);
		printf("Max files: %d\n", max_files);
	}
	
	return 0;
}

static void usage(void)
{
	fprintf(stderr, "Usage: load_distro [-v] -d <distro_dir>\n");
	exit(1);
	/* NOT_REACHED */
}

int main(int argc, char * argv[]) 
{
	char *distrolist_dir = NULL;
	char filename[FILENAME_LENGTH];
	int opt;

	while ((opt = getopt(argc, argv, "d:v")) != -1) {
		switch (opt) {
		case 'd':
			distrolist_dir = optarg;
			continue;
		case 'v':
			verbose++;
			continue;
		default:
			usage();
			/* NOT_REACHED */
		}
	}

	/* Check for arguments */

	if (distrolist_dir == NULL) {
		warnx("distrolist directory name missing");
		usage();
		/* NOT_REACHED */
	}

	load_distro(distrolist_dir);

	snprintf(filename, FILENAME_LENGTH-1, "%s/distro.blob", distrolist_dir);

	write_data(filename);

	return 0;
}