#include <unistd.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include <sys/stat.h>
#include <linux/limits.h>
#include <libgen.h>
#include <termios.h>
#include <stdio.h>

#include "libnpass/libnpass.h"
#include "libnpass/gpg.h"
#include "libnpass/util.h"

#include "util.h"

#define DEF_PASS_DIR	"pass"
#define FPR_MAX		256

static char pass_dir[PATH_MAX] = {0};
const char *pass_gen_set[] = {
	"0123456789",

	"0123456789"
	"abcdefghijklmnopqrstuvwxyz"
	"ABCDEFGHIJKLMNOPQRSTUVWXYZ",

	"0123456789"
	"abcdefghijklmnopqrstuvwxyz"
	"ABCDEFGHIJKLMNOPQRSTUVWXYZ"
	"!\"#$%&'()*+,-./:;<=>?@[\\]^_`{|}~",
};

int set_pass_dir(void);

int set_pass_dir(void) {
	const char *env;

	env = getenv("PASSWORD_STORE_DIR");
	if (env) {
		strncpy(pass_dir, env, sizeof(pass_dir) - 1);
		return 0;
	}

	env = getenv("XDG_DATA_HOME");
	if (env) {
		snprintf(pass_dir, sizeof(pass_dir) - 1, "%s/%s", env,
			DEF_PASS_DIR);
		return 0;
	}

	env = getenv("HOME");
	if (env) {
		snprintf(pass_dir, sizeof(pass_dir) - 1, "%s/%s/%s", env,
			".local/share", DEF_PASS_DIR);
		return 0;
	}

	return 1;
}

int pass_init(const char *fpr)
{
	int r;
	char gpg_id_path[PATH_MAX];
	FILE *gpg_id;

	r = set_pass_dir();
	if (r)
		err_ret(1, "PASSWORD_STORE_DIR not set");

	r = gpg_key_validate(fpr);
	if (r)
		err_ret(1, "key not usable, try gpg --full-generate-key");


	r = r_mkdir(pass_dir, S_IRWXU);
	if (r)
		err_ret(1, "%s %s", pass_dir, strerror(errno));

	r = snprintf(gpg_id_path, sizeof(gpg_id_path), "%s/%s", pass_dir, ".gpg-id");
	if (r > (int) sizeof(gpg_id_path))
		err_ret(1, "path exceeded PATH_MAX");

	gpg_id = fopen(gpg_id_path, "w");
	if (!gpg_id)
		err_ret(1, "%s %s", gpg_id_path, strerror(errno));

	r = fwrite(fpr, strlen(fpr), 1,gpg_id);
	fclose(gpg_id);
	if (!r)
		err_ret(1, "write failed");

	return 0;
}

int pass_cat(FILE *out, const char *path)
{
	int r;
	char pass_path[PATH_MAX];

	r = set_pass_dir();
	if (r)
		err_ret(1, "PASSWORD_STORE_DIR not set");

	r = snprintf(pass_path, sizeof(pass_path), "%s/%s.gpg", pass_dir, path);
	if (r >= (int) sizeof(pass_path))
		err_ret(1, "path exceeded PATH_MAX");

	r = gpg_decrypt(out, pass_path);
	return r;
}

ssize_t pass_getpass(char **lineptr, size_t *n, FILE *stream)
{
	ssize_t r;
	struct termios new, old;

	r = tcgetattr(fileno(stream), &old);
	if (r)
		return -1;

	new = old;
	new.c_lflag &= ~ECHO;
	r = tcsetattr(fileno(stream), TCSAFLUSH, &new);
	if (r)
		return -1;

	r = getline (lineptr, n, stream);
	if (r > 0 && (*lineptr)[r - 1] == '\n')
		(*lineptr)[r - 1] = '\0';

	(void) tcsetattr (fileno (stream), TCSAFLUSH, &old);

	return r;
}

int pass_gen(pass_gen_t gen, char *pass, size_t n)
{
	int r;
	FILE *rand;
	size_t  pass_gen_len;


	if (n <= 0)
		err_ret(1, "small password");

	rand = fopen("/dev/urandom", "r");
	if (!rand)
		err_ret(1, "%s", strerror(errno));

	r = fread(pass, sizeof(pass[0]), n, rand);
	if (r != (int) n)
		err_ret(1, "fread failed");

	pass_gen_len = strlen(pass_gen_set[gen]);
	for (size_t i = 0; i < n; i++)
		pass[i] = pass_gen_set[gen][pass[i] % (pass_gen_len - 1)];

	return 0;
}

int pass_add(const char *path, const char *pass, size_t n)
{
	int r;
	char *rc;
	FILE *gpg_id, *out_stream;
	char gpg_id_path[PATH_MAX], fpr[FPR_MAX], pass_path[PATH_MAX];

	r = set_pass_dir();
	if (r)
		err_ret(1, "PASSWORD_STORE_DIR not set");

	r = snprintf(gpg_id_path, sizeof(gpg_id_path), "%s/%s", pass_dir, ".gpg-id");
	if (r > (int) sizeof(gpg_id_path))
		err_ret(1, "path exceeded PATH_MAX");

	gpg_id = fopen(gpg_id_path, "r");
	if (!gpg_id)
		err_ret(1, "%s %s", gpg_id_path, strerror(errno));

	rc = fgets(fpr, sizeof(fpr), gpg_id);
	if (!rc)
		err_ret(1, "failed to read %s", gpg_id_path);
	fclose(gpg_id);
	util_strtrim(fpr);

	r = gpg_key_validate(fpr);
	if (r)
		err_ret(1, "invalid key , try gpg --list-keys");

	// TODO: guard against .*\.gpg\.gpg[/$]
	r = snprintf(pass_path, sizeof(pass_path), "%s/%s.gpg", pass_dir, path);
	if (r > (int) sizeof(pass_path))
		err_ret(1, "path exceeded PATH_MAX");

	rc = strdup(pass_path);
	if (!rc)
		err_ret(1, "%s", strerror(errno));
	(void) r_mkdir(dirname(rc), S_IRWXU);
	free(rc);

	r = access(pass_path, F_OK);
	if (!(errno & ENOENT))
		err_ret(1, "an entry already exists for %s", path);

	out_stream = fopen(pass_path, "w");
	if (!out_stream)
		err_ret(1, "%s", strerror(errno));

	r = gpg_encrypt(out_stream, fpr, pass, n);

	fclose(out_stream);
	return r;
}

int pass_rm(const char *path)
{

	int r = 0;
	char gpg_path[PATH_MAX], abs_path[PATH_MAX];

	r = set_pass_dir();
	if (r)
		err_ret(1, "PASSWORD_STORE_DIR not set");

	r = snprintf(gpg_path, sizeof(gpg_path), "%s.gpg", path);
	if (r > (int) sizeof(gpg_path))
		err_ret(1, "path exceeded PATH_MAX");

	r = snprintf(abs_path, sizeof(gpg_path), "%s/%s", pass_dir, gpg_path);
	if (r > (int) sizeof(abs_path))
		err_ret(1, "path exceeded PATH_MAX");

	// TODO: guard against .*\.gpg\.gpg[/$]
	r = unlink(abs_path);
	if (r)
		err_ret(1, "%s %s", abs_path, strerror(errno));

	return r_rmdir(pass_dir, dirname(gpg_path));
}