/* SPDX-License-Identifier: Apache-2.0
 * (c) 2025, Konstantin Demin
 */

#ifndef INCLUDE_OVERLAY_HH
#define INCLUDE_OVERLAY_HH 1

#include <cstring>

extern "C" {
	#include <sys/types.h>
}

#include "overlay-common.hh"

#include "print.hh"
#include "sort.hh"
#include "xxhash.hh"

struct ovl_dirspec_t {
	dev_t       dev;
	ino_t       ino;
	int         fd;
	ovl_path_t  root;
};
typedef std::vector<ovl_dirspec_t>  ovl_dirspec_vec;

enum ovl_rootspec_flags : uint32_t {
	none = 0,

	// relative path (if possible)
	relative = (1 << 0),
};

// forward declaration
struct ovl_entry_t;
typedef std::vector<ovl_entry_t>  ovl_entry_vec;

enum struct ovl_entry_kind : uint32_t {
	unknown = 0,

	// entry may have it's own entries
	directory,

	// entry may NOT have it's own entries
	// this applies to:
	// - regular files
	// - directories at maximum depth (!)
	// - block and character devices
	// - pipes (FIFO)
	// - sockets
	file,
};

struct ovl_entry_t {
	ovl_entry_kind  type;
	int32_t         root_id;
	xxhash_t        name_hash;
	ovl_entry_vec   children;
	ovl_name_t      name;

	ovl_entry_t() {
		root_id = -1;
		type = ovl_entry_kind::unknown;
		name_hash = 0;
		children = ovl_entry_vec();
		(void) memset(&name, 0, sizeof(name));
	}
};

struct ovl_result {
	ovl_path_vec   roots;
	ovl_entry_vec  entries;

	ovl_result() {
		roots = ovl_path_vec();
		entries = ovl_entry_vec();
	}
};

bool arg_to_rootspec(const char * arg, ovl_dirspec_t * path, uint32_t flags = ovl_rootspec_flags::none);

bool is_empty_dir(int dirfd);

ovl_result process_overlay(ovl_dirspec_vec & roots, sort_mode sort = sort_mode::none, unsigned int depth = ovl_depth_max);

void list_overlay(const ovl_result & overlay, print_mode print = print_mode::normal);
int merge_overlay(const ovl_result & overlay, const ovl_dirspec_t & target);

#endif /* INCLUDE_OVERLAY_HH */