#include <dirent.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include <sys/stat.h>
#include <sys/types.h>

#define REPO   ".cvn"
#define INDEX  "index"

#define MAX_SUBDIRS  256

static inline void init(int argc, char *argv[]);
static inline void status(int argc, char *argv[]);

/* helpers */
static inline void traverse(void);

struct command {
	char *name;
	void (*func)(int argc, char *argv[]);
};

struct command cmd[] = {
	{"init", init},
	{"status", status},
	{NULL, NULL}
};

int main(int argc, char *argv[])
{
	uint8_t i;

	if (argc < 2) {
		fprintf(stderr, "Usage: %s <command> [<args>]\n", argv[0]);
		return 1;
	}
	
	for (i = 0; cmd[i].name != NULL; i++) {
		if (strcmp(argv[1], cmd[i].name) == 0) {
			cmd[i].func(argc - 1, argv + 1);
			return 0;
		}
	}

	return 0;
}

static inline void init(int argc, char *argv[])
{
	char *branch;
	int opt, repo_fd, idx_fd;

	optind = 1; 
	branch = "master";

	while ((opt = getopt(argc, argv, "b:")) != -1) {
		switch (opt) {
			case 'b': 
				branch = optarg;
				break;
			default: 
				break;
		}
	}

	if (mkdir(REPO, 0755) == -1) {
		if (errno != EEXIST) {
			perror("Failed to create repository");
			return;
		}
	}

	if ((repo_fd = open(REPO, O_RDONLY | O_DIRECTORY)) == -1) {
		perror("Failed to open repository");
		return;
	}

	if ((idx_fd = openat(repo_fd, INDEX, O_WRONLY | O_CREAT | O_EXCL, 0644)) == -1) {
		if (errno != EEXIST) {
			close(repo_fd);
			perror("Failed to create index");
			return;
		}
	} else
		close(idx_fd);

	close(repo_fd);
	printf("Initialized repository in %s\n", REPO);
}

static inline void status(int argc, char *argv[])
{
	traverse();
}

static inline void traverse(void)
{
	DIR *dir;
	char *path, *rel_path;
	struct stat st;
	struct dirent *entry;
	int subdirs_len;
	char *subdirs[MAX_SUBDIRS];
	
	subdirs_len = 0;
	subdirs[subdirs_len++] = strdup(".");

	while (subdirs_len) {
		path = subdirs[--subdirs_len];
		if (!(dir = opendir(path))) {
			warn("Failed to open directory %s", path);
			free(path);
			continue;
		}

		while ((entry = readdir(dir)) != NULL) {
			if (strcmp(entry->d_name, ".") == 0 || strcmp(entry->d_name, "..") == 0)
				continue;
			if (asprintf(&rel_path, "%s/%s", path, entry->d_name) == -1)
				err(1, "asprintf() failed");
			if (lstat(rel_path, &st) == -1) {
				warn("lstat() failed: %s", rel_path);
				free(rel_path);
				continue;
			}
			if (S_ISDIR(st.st_mode)) {
				if (subdirs_len >= MAX_SUBDIRS)
					errx(1, "Repository too large: directory tree too deep/wide");
				subdirs[subdirs_len++] = rel_path;
			} else {
				printf("File: %s\n", rel_path);
				free(rel_path);
			}
		}

		free(path);
		closedir(dir);
	}
}