#include <bluray.h>
#include <errno.h>
#include <filesystem.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>

/* function declarations */
static void basename(char dst[], const char src[]);
static int copy_dir(const char path[]);
static int copy_file(const char src[], const char dst[]);
static void open_bluray(const char device[], const char keyfile[]);
static void print_help(void);
static void print_version(void);
static void print_usage(void);

/* variables */
static BLURAY *bluray;

void
basename(char dst[], const char src[])
{
	int i;
	size_t len, offset;

	len = strlen(src);

	for (i = len - 1; i >= 0; i--) {
		offset = i + 1;
		if (src[i] == '/' && offset < len && (len - offset) < 256) {
			strcpy(dst, src + offset);
			return;
		}
	}	

	if (len < 256)
		strcpy(dst, src);
	else
		strcpy(dst, "");
}

int
copy_dir(const char path[])
{
	int all_good, read;
	struct bd_dir_s *dir;
	BD_DIRENT *dirent;
	char *new_path;

	all_good = 1;
	read = 0;

	dir = bd_open_dir(bluray, path);
	if (dir == NULL) {
		fprintf(stderr, "Can't open Blu-ray dir %s.\n", path);
		return 0;
	}

	if (strcmp(path, "") != 0 &&
	    mkdir(path, 0755) == -1 && errno != EEXIST) {
		fprintf(stderr, "Can't create destination dir %s.\n", path);
		return 0;
	}
	
	dirent = malloc(sizeof(BD_DIRENT));
	if (dirent == NULL) {
		fprintf(stderr, "Can't allocate memory for BD_DIRENT.\n");
		dir->close(dir);
		return 0;
	}

	do {
		read = dir->read(dir, dirent);
		if (read == -1) {
			break;
			// [libbluray-devel] UDF dir read does not return 1 on EOF
			// https://mailman.videolan.org/pipermail/libbluray-devel/2023-September/003297.html
			// https://code.videolan.org/videolan/libbluray/-/blob/master/src/libbluray/disc/udf_fs.c#L110
			// https://code.videolan.org/videolan/libudfread/-/blob/master/src/udfread.c#L1375
			//fprintf(stderr, "Can't read Blu-ray dir %s.\n", path);
			//return 0;
		}

		new_path = malloc(sizeof(char) * (strlen(path) + strlen(dirent->d_name) + 2));
		if (new_path == NULL) {
			fprintf(stderr, "Can't allocate memory for new_path.\n");
			all_good = 0;
			break;
		}
		strcpy(new_path, path);
		if (strcmp(path, "") != 0)
			strcat(new_path, "/");
		strcat(new_path, dirent->d_name);

		if (strchr(dirent->d_name, '.') == NULL) {
			if (!copy_dir(new_path))
				all_good = 0;
		} else {
			if (!copy_file(new_path, new_path))
				all_good = 0;
		}

		free(new_path);
	} while (read == 0);

	free(dirent);

	dir->close(dir);

	return all_good;
}

int
copy_file(const char src[], const char dst[])
{
	struct bd_file_s *src_file;
	uint8_t bytes[6144];
	FILE *dst_file;
	int64_t i, read, written;

	src_file = bd_open_file_dec(bluray, src);
	if (src_file == NULL) {
		fprintf(stderr, "Can't open Blu-ray file %s.\n", src);
		return 0;
	}
	dst_file = fopen(dst, "w");
	if (dst_file == NULL) {
		fprintf(stderr, "Can't open destination file %s.\n", dst);
		return 0;
	}

	src_file->seek(src_file, 0, SEEK_SET);
	fseek(dst_file, 0, SEEK_SET);
	do {
		read = src_file->read(src_file, bytes, 6144);
		for (i = 0; i < read && read > 0; i++) {
			written = fputc(bytes[i], dst_file);
			if (written == EOF) {
				fprintf(stderr, "Destination write error on %s.\n", dst);
				return 0;
			}
		}
	}
	while (read > 0);
	if (read < 0) {
		fprintf(stderr, "Blu-ray read error on %s.\n", src);
	}

	fclose(dst_file);
	src_file->close(src_file);

	return 1;
}

int
main(int argc, char *argv[])
{
	int success = 0;
	char dst[256];
	
	if (argc == 2) {
		if (!strcmp(argv[1], "-h") || !strcmp(argv[1], "--help"))
			print_help();
		else if	(!strcmp(argv[1], "-v") || !strcmp(argv[1], "--version"))
			print_version();
	}

	if (argc < 3 || argc > 5) {
		print_usage();
		return 1;
	}

	open_bluray(argv[1], argv[2]);

	switch (argc) {
		case 3:
			success = copy_dir("");
			break;
		case 4:
			basename(dst, argv[3]);
			if (!strcmp(dst, "")) {
				fprintf(stderr, "Invalid file name.\n");
				return 1;
			}
			success = copy_file(argv[3], dst);
			break;
		case 5:
			success = copy_file(argv[3], argv[4]);
			break;
	}

	bd_close(bluray);

	return !success;
}

void
open_bluray(const char device[], const char keyfile[])
{
	bluray = bd_open(device, keyfile);
	if (bluray == NULL) {
		fprintf(stderr, "Can't open device %s.\n", device);
		exit(1);
	}
}

void
print_help(void)
{
	print_usage();
	fprintf(stdout, "\n");
	fprintf(stdout, "Without FILE, the whole disc will be copied to the current directory.\n");
	fprintf(stdout, "FILE must be a file path relative to the disc root.\n");
	fprintf(stdout, "\n");
	fprintf(stdout, "Without DEST, the base FILE will be saved to the current directory.\n");
	fprintf(stdout, "DEST path must include file name.\n");
	fprintf(stdout, "\n");
	fprintf(stdout, "\"bluraybackup -h\" or \"--help\" prints this help text.\n");
	fprintf(stdout, "\"bluraybackup -v\" or \"--version\" prints version and license information.\n");
	fprintf(stdout, "\n");
	fprintf(stdout, "bluraybackup exits with 0 when the whole disc or FILE has been copied,\n");
	fprintf(stdout, "otherwise it exits with 1.\n");
	exit(1);
}

void
print_usage(void)
{
	fprintf(stdout, "Usage: bluraybackup <DEVICE> <KEYFILE> [FILE] [DEST]\n");
}

void
print_version(void)
{
	fprintf(stdout, "bluraybackup " VERSION "\n");
	fprintf(stdout, "Copyright (c) 2023 Matteo Bini\n");
	fprintf(stdout, "License: GPLv3+ <https://www.gnu.org/licenses/gpl.html>.\n");
	fprintf(stdout, "This is free software: you are free to change and redistribute it.\n");
	fprintf(stdout, "There is NO WARRANTY, to the extent permitted by law.\n");
	fprintf(stdout, "\n");
	fprintf(stdout, "Written by Matteo Bini.\n");
	exit(1);
}