diff --git a/CMakeLists.txt b/CMakeLists.txt
index 006dfd3..987d5c6 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -23,6 +23,7 @@ add_subdirectory(src/modals)
 add_subdirectory(src/lib)
 add_subdirectory(src/utils)
 add_subdirectory(src/windows)
+add_subdirectory(src/core)
 
 add_subdirectory(src) 
 
diff --git a/TODO.md b/TODO.md
index c844be6..d5d0268 100644
--- a/TODO.md
+++ b/TODO.md
@@ -1,13 +1,16 @@
 # TODO:
 
 ## Current:
-- [ ] Sorting in the file list (local files)
-- [ ] Resume download
-- [ ] Separate common structures in the common.h
+- [ ] Sorting in the file list (local files):
+    - [ ] Testing env
+    - [ ] Test dlist
+    - [ ] Dlist sort
 
 ## Global tasks:
 - [ ] Testing
 - [ ] Documentation
+- [ ] Resume download
+- [ ] Separate common structures in the common.h
 
 ## Features:
 - [ ] Files removal
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index f2bdb97..ee7a67e 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -20,17 +20,21 @@ elseif(
   endif()
 endif()
 
-file(GLOB M_SOURCES "*.c")
-
 if(DEV_WIDGET) 
-  list(FILTER M_SOURCES EXCLUDE REGEX "main\\.c$")
+    target_sources(zbbs-client-tui
+    PRIVATE
+        main_dev_widget.c
+)
 else()
-  list(FILTER M_SOURCES EXCLUDE REGEX "main_dev_widget\\.c$")
+  target_sources(zbbs-client-tui
+    PRIVATE
+        main.c
+)
 endif()
 
-target_sources(zbbs-client-tui
-    PRIVATE
-        ${M_SOURCES}
+add_library(common INTERFACE)
+target_sources(common
+    PUBLIC FILE_SET HEADERS FILES common.h
 )
 
 target_link_libraries(zbbs-client-tui 
@@ -41,5 +45,6 @@ target_link_libraries(zbbs-client-tui
         bstring
         windows
         utils
+        common
         ${CURSES_LIBRARIES}
 )
\ No newline at end of file
diff --git a/src/common.h b/src/common.h
index d339357..1b5dd30 100644
--- a/src/common.h
+++ b/src/common.h
@@ -4,8 +4,22 @@
 #ifndef COMMON_H
 #define COMMON_H
 
+#include <d_array.h>
+#include <ncursesw/ncurses.h>
+#include <stdbool.h>
+#include <stddef.h>
 #include <stdint.h>
 
+#define LOCAL_PORT 1999
+#define SERVER_PORT 2000
+#define LISTEN_QLEN 32
+#define INBUFSIZE 1024
+#define DOWNLOADS_DIR "./Downloads"
+#define DIALOGUE_TITLE 64
+#define DIALOGUE_TEXT 4096
+#define INPUT_TEXT DIALOGUE_TITLE
+#define PACKAGE_SIZE INBUFSIZE * 10
+
 typedef struct {
   int32_t cur_y, cur_x;
   int32_t max_y, max_x;
@@ -25,4 +39,270 @@ struct action_key {
   int (*callback)(void *app, void *d_args);
 };
 
+typedef struct fl_item {
+  size_t size;
+  char *name;
+  char *description;
+  char *owner;
+  struct fl_item *next;
+} fl_item_t;
+
+enum main_window_type {
+  mw_fl_server, /* file list on the server */
+  mw_fl_local,  /* local file list */
+  mw_f_desc,    /* file description */
+};
+
+typedef void(draw_f_t)(void *fui);
+
+typedef struct main_window {
+  enum main_window_type type;
+  void *ui; /* structure which describes window UI */
+  int32_t (*cb_b_press)(void *app, void *args); /* callback on button press */
+  void (*cb_ui_refresh)(void *app);             /* refresh callback */
+  void (*reset)(void *app); /* function to reset the state of the window */
+  draw_f_t *draw;
+  struct action_key *b_keys;
+  int32_t b_keys_len;
+} main_window_t;
+
+
+typedef struct file_args {
+  int file_d;
+  fl_item_t f_selected;
+  fl_item_t *l_start;
+  fl_item_t *l_current;
+} file_args_t;
+
+
+typedef struct params {
+  unsigned short port;
+  unsigned addr;
+  char *uname;
+  char *pass;
+  char privileges;
+  int32_t sd;
+  int32_t is_connected : 1;
+} params_t;
+
+enum state {
+  /* TUI-based */
+  S_N_D,
+  S_ASK_SEVER_IP,
+  S_ASK_LOGIN_TYPE,
+  S_ASK_LOGIN_USER,
+  S_ASK_REGISTER,
+  S_WAIT_SERVER,
+  S_PREP_SERVER_MESSAGE,
+  S_PRINT_SERVER_MESSAGE,
+  S_FILE_LIST,
+  S_WAIT_PASS,
+  /* S_FILE_SELECT, */
+  S_DOWNLOAD_FILE,
+  S_UPLOAD_PARAMS,
+  S_UPLOAD_FILE,
+  /* S_UPLOAD_FILE_SELECT, */
+  S_UPLOAD_REQUESTED,
+  S_UPLOAD_SERVER_FINISHES,
+  S_ASK_USER_BEFORE_LOGIN,
+  S_ERR,
+  S_NEXT_ACTION,
+  S_WAIT_REGISTER_CONFIRMATION,
+  S_WAIT_USER_DESCRIPTION,
+  /* Legacy */
+  WAIT_SERVER_INIT,
+  WAIT_SERVER,
+  WAIT_REGISTER,
+  WAIT_REGISTER_CONFIRMATION,
+  WAIT_CLIENT,
+};
+
+enum package_signal { sig_continue, sig_cancel, sig_finish, sig_pause };
+
+typedef struct {
+  enum package_signal signal;
+  size_t package_size;
+} s_file_pd_t; /* file package descriptor */
+
+typedef struct p_file {
+  char *name;
+  char *path;
+  char *description;
+  size_t size;
+  size_t rest;
+  size_t package_rest;
+  int32_t it_count;
+  size_t it_interval;
+  enum package_signal signal;
+  int fd;
+} p_file_t;
+
+typedef struct query_args {
+  int32_t sd;
+  int32_t buf_used;
+  p_file_t *file;
+  enum state state;
+  char buf[INBUFSIZE];
+  bool from_server;
+  params_t *params;
+  struct {
+    char *text;
+    int32_t capacity;
+    int32_t size;
+  } server_message;
+  main_window_t *main_ui;
+  void *progress_bar;
+  void *active_dialogue;
+  void *notification;
+} query_args_t;
+
+enum w_dialogue_color_scheme { dc_normal, dc_alert };
+
+enum w_g_type { g_content, g_action };
+
+enum w_g_dir {
+  horizontal,
+  vertical,
+};
+
+enum w_type {
+  w_end,
+  w_button,
+  w_box,
+  w_group,
+  w_input,
+  w_checkbox,
+  w_progress,
+};
+
+enum w_val_type {
+  val_num,
+  val_ptr,
+  val_nul,
+};
+
+struct w_val_t {
+  enum w_val_type type;
+  union {
+    void *ptr;
+    int32_t num;
+  } val;
+};
+
+typedef struct {
+  int32_t id;
+  int32_t idx; /* element index in the group */
+  void *element;
+  enum w_type type;
+  enum w_g_type g_type;
+  bool is_default;
+  struct w_val_t val;
+} w_g_el_t;
+
+/* widget callback response code */
+enum w_cbrp_code {
+  cbrc_none, /* default */
+  cbrp_val,
+  cbrp_g_el, /* element of type group_el_t */
+  cbrp_err
+};
+
+enum w_pmt_attrs {
+  PMT_POS_CENTER = 01,
+  PMT_ALIGN_CENTER = 03,
+};
+
+/* widget callback response data */
+typedef struct {
+  enum w_cbrp_code code;
+  struct w_val_t val;
+} w_cbrp_data;
+
+typedef struct {
+  void *app;
+  void *element;
+  void *data;
+  w_cbrp_data resp_data;
+  void *active_el;
+} w_cb_args_t;
+
+typedef int32_t (*w_cb_press_t)(void *app, void *data);
+
+typedef void (*w_cb_t)(w_cb_args_t *args);
+
+typedef struct w_t {
+  int32_t id;
+  char title[DIALOGUE_TITLE];
+  struct {
+    int32_t y;
+    int32_t x;
+  } cur; /* cursor position */
+  struct {
+    int32_t y;
+    int32_t x;
+  } sz; /* size */
+  struct {
+    int32_t y;
+    int32_t x;
+  } m; /* margin (relative to the parent) */
+  struct {
+    int32_t y;
+    int32_t x;
+  } ps; /* position (relative to the window) */
+  WINDOW *const *parent_win;
+  struct w_t *w_parent;
+  w_cb_t callback;
+} w_t;
+
+typedef struct group_el_init_t {
+  enum w_type type;
+  bool is_default;
+  bool is_hidden_value;
+  char label[DIALOGUE_TITLE];
+  int32_t length;
+  enum w_g_dir direction;
+  union {
+    int32_t num;
+  } val;
+  struct group_el_init_t *children;
+} w_group_el_init_t;
+
+typedef struct group_t {
+  w_t w;
+  w_g_el_t *elements;
+  enum w_g_dir direction;
+  int32_t count;
+  int32_t first_id, last_id;
+  struct group_t *parent_group;
+} w_group_t;
+
+typedef struct {
+  w_t w;
+  WINDOW *win;
+  w_group_t *g_content;
+  w_group_t *g_action;
+  w_g_el_t *active_el;
+  char text[DIALOGUE_TEXT];
+  bool is_initiated;
+  bool needs_update;
+  bool needs_destroy;
+  coordinates_t *p_coordinates;
+  enum w_dialogue_color_scheme color_scheme;
+  d_array_ptr_t id_map;
+} w_dialogue_t;
+
+typedef struct app_t {
+  WINDOW *win;
+  w_dialogue_t modal;
+  params_t *params;
+  coordinates_t coordinates;
+  query_args_t *query_args;
+  file_args_t *file_args;
+  void (*active_callback)(w_cb_args_t *args);
+  void (*callback_after_notification)(struct app_t *);
+  void *active_widget;
+  wchar_t *top_text;
+  main_window_t main_ui;
+} app_t;
+
 #endif
\ No newline at end of file
diff --git a/src/core/CMakeLists.txt b/src/core/CMakeLists.txt
new file mode 100644
index 0000000..3c4f938
--- /dev/null
+++ b/src/core/CMakeLists.txt
@@ -0,0 +1,23 @@
+add_library(core STATIC)
+
+file(GLOB M_SOURCES "*.c")
+
+target_sources(core 
+    PRIVATE 
+        ${M_SOURCES}
+    PUBLIC
+        FILE_SET HEADERS
+        FILES
+            core.h
+)
+target_link_libraries(core 
+    PRIVATE
+        common
+        widget_core
+        widget
+        bstring
+        utils
+        modals
+        windows
+)
+
diff --git a/src/app.c b/src/core/app.c
similarity index 99%
rename from src/app.c
rename to src/core/app.c
index d33e55c..116084e 100644
--- a/src/app.c
+++ b/src/core/app.c
@@ -1,7 +1,7 @@
 /* SPDX-License-Identifier: MIT */
 /* Copyright (c) 2026 Oleksandr Zhylin */
 
-#include "../app.h"
+#include "app.h"
 #include <locale.h>
 #include <ncursesw/ncurses.h>
 #include <netinet/in.h>
diff --git a/src/app.h b/src/core/app.h
similarity index 56%
rename from src/app.h
rename to src/core/app.h
index 005c784..60a04f3 100644
--- a/src/app.h
+++ b/src/core/app.h
@@ -4,9 +4,7 @@
 #ifndef APP_H
 #define APP_H
 
-#include "../main.h"
-#include "../common.h"
-#include "dialogue.h"
+#include <common.h>
 #include <ncursesw/ncurses.h>
 #include <widget_core.h>
 #include <bstrlib.h>
@@ -15,20 +13,6 @@ typedef enum {
   modal_color_pair = 3,
 } app_color;
 
-typedef struct app_t {
-  WINDOW *win;
-  w_dialogue_t modal;
-  params_t *params;
-  coordinates_t coordinates;
-  query_args_t *query_args;
-  file_args_t *file_args;
-  void (*active_callback)(w_cb_args_t *args);
-  void (*callback_after_notification)(struct app_t *);
-  void *active_widget;
-  wchar_t *top_text;
-  main_window_t main_ui;
-} app_t;
-
 app_t *app_init(app_t *app);
 void   app_init_nc(void);
 void   app_destroy(app_t *app, int32_t exit_code);
diff --git a/src/connection.c b/src/core/connection.c
similarity index 98%
rename from src/connection.c
rename to src/core/connection.c
index 71cf921..aca801d 100644
--- a/src/connection.c
+++ b/src/core/connection.c
@@ -1,8 +1,8 @@
 /* SPDX-License-Identifier: MIT */
 /* Copyright (c) 2026 Oleksandr Zhylin */
 
-#include "alert.h"
-#include "main.h"
+#include "app.h"
+#include <widget.h>
 #include <arpa/inet.h>
 #include <errno.h>
 #include <ncursesw/ncurses.h>
diff --git a/src/connection.h b/src/core/connection.h
similarity index 95%
rename from src/connection.h
rename to src/core/connection.h
index 5c74653..a10eaf8 100644
--- a/src/connection.h
+++ b/src/core/connection.h
@@ -3,7 +3,7 @@
 
 #ifndef CONNECTION_H
 #define CONNECTION_H
-#include "main.h"
+
 #include <widget.h>
 
 bool connect_to_server(app_t *params);
diff --git a/src/core/core.h b/src/core/core.h
new file mode 100644
index 0000000..17b0206
--- /dev/null
+++ b/src/core/core.h
@@ -0,0 +1,12 @@
+#ifndef CORE_H
+#define CORE_H
+
+#include "app.h"
+#include "connection.h"
+#include "draw_modal.h"
+#include "file_processor.h"
+#include "fs.h"
+#include "query.h"
+#include "server.h"
+
+#endif
\ No newline at end of file
diff --git a/src/draw_modal.c b/src/core/draw_modal.c
similarity index 98%
rename from src/draw_modal.c
rename to src/core/draw_modal.c
index 1dfeef5..b88a076 100644
--- a/src/draw_modal.c
+++ b/src/core/draw_modal.c
@@ -1,7 +1,6 @@
 /* SPDX-License-Identifier: MIT */
 /* Copyright (c) 2026 Oleksandr Zhylin */
 
-#include "main.h"
 #include <modals.h>
 #include <widget.h>
 
diff --git a/src/draw_modal.h b/src/core/draw_modal.h
similarity index 98%
rename from src/draw_modal.h
rename to src/core/draw_modal.h
index 5fb8576..9aa5e40 100644
--- a/src/draw_modal.h
+++ b/src/core/draw_modal.h
@@ -3,6 +3,8 @@
 
 #ifndef DRAW_MODAL_H
 #define DRAW_MODAL_H
+
 #include <widget.h>
+
 void app_draw_modal(app_t *app);
 #endif
\ No newline at end of file
diff --git a/src/file_processor.c b/src/core/file_processor.c
similarity index 99%
rename from src/file_processor.c
rename to src/core/file_processor.c
index c272a30..71769f8 100644
--- a/src/file_processor.c
+++ b/src/core/file_processor.c
@@ -2,7 +2,6 @@
 /* Copyright (c) 2026 Oleksandr Zhylin */
 
 #include "alert.h"
-#include "dialogue.h"
 #include "server.h"
 #include <arpa/inet.h>
 #include <fcntl.h>
@@ -20,10 +19,10 @@
 #include <termios.h>
 #include <unistd.h>
 #include <widget.h>
-#include <windows.h>
+#include <common.h>
+#include <windows/file_list.h>
 
 #include "file_processor.h"
-#include "main.h"
 #include "query.h"
 
 static void fl_add(fl_item_t **cur, fl_item_t **start, char *fname);
diff --git a/src/file_processor.h b/src/core/file_processor.h
similarity index 97%
rename from src/file_processor.h
rename to src/core/file_processor.h
index ae085e4..8a70555 100644
--- a/src/file_processor.h
+++ b/src/core/file_processor.h
@@ -4,7 +4,7 @@
 #ifndef FILE_PROCESSOR_H
 #define FILE_PROCESSOR_H
 
-#include "main.h"
+#include "common.h"
 
 void file_list(file_args_t *f_args, query_args_t *q_args);
 void file_download(file_args_t *f_args, query_args_t *q_args);
@@ -16,4 +16,5 @@ int32_t file_upload_open(char *dpath, char *fname, query_args_t *q_args);
 void fl_clear(fl_item_t **start, fl_item_t **arg_current);
 int32_t ui_file_select(file_args_t *f_args, query_args_t *q_args, int32_t idx);
 void clear_file_in_query(query_args_t *q_args);
+
 #endif
\ No newline at end of file
diff --git a/src/fs.c b/src/core/fs.c
similarity index 100%
rename from src/fs.c
rename to src/core/fs.c
diff --git a/src/fs.h b/src/core/fs.h
similarity index 100%
rename from src/fs.h
rename to src/core/fs.h
diff --git a/src/query.c b/src/core/query.c
similarity index 99%
rename from src/query.c
rename to src/core/query.c
index 7dadbdc..4ff17aa 100644
--- a/src/query.c
+++ b/src/core/query.c
@@ -1,7 +1,6 @@
 /* SPDX-License-Identifier: MIT */
 /* Copyright (c) 2026 Oleksandr Zhylin */
 
-#include "query.h"
 #include <arpa/inet.h>
 #include <fcntl.h>
 #include <ncursesw/ncurses.h>
@@ -23,13 +22,12 @@
 #include <modals.h>
 #include <widget.h>
 #include <widget_core.h>
-#include <windows.h>
 
+#include "app.h"
+#include "query.h"
 #include "alert.h"
 #include "connection.h"
-#include "dialogue.h"
 #include "file_processor.h"
-#include "main.h"
 #include "main_window.h"
 #include "server.h"
 #include "types.h"
diff --git a/src/query.h b/src/core/query.h
similarity index 93%
rename from src/query.h
rename to src/core/query.h
index 740e39c..d4e7113 100644
--- a/src/query.h
+++ b/src/core/query.h
@@ -4,8 +4,6 @@
 #ifndef QUERY_H
 #define QUERY_H
 
-#include "../app.h"
-#include "main.h"
 #include <widget.h>
 
 void query_loop(app_t *);
diff --git a/src/server.c b/src/core/server.c
similarity index 99%
rename from src/server.c
rename to src/core/server.c
index 6503dcc..320bee7 100644
--- a/src/server.c
+++ b/src/core/server.c
@@ -1,9 +1,8 @@
 /* SPDX-License-Identifier: MIT */
 /* Copyright (c) 2026 Oleksandr Zhylin */
 
-#include "../app.h"
+#include "app.h"
 #include "dialogue.h"
-#include "main.h"
 #include "query.h"
 #include <arpa/inet.h>
 #include <fcntl.h>
@@ -18,7 +17,7 @@
 #include <termios.h>
 #include <unistd.h>
 #include <widget.h>
-#include <windows.h>
+#include <windows/file_list.h>
 
 void ask_uname_and_password(params_t *params);
 void ask_register(params_t *params, char *email);
diff --git a/src/server.h b/src/core/server.h
similarity index 91%
rename from src/server.h
rename to src/core/server.h
index e7f63fa..95ffc22 100644
--- a/src/server.h
+++ b/src/core/server.h
@@ -4,8 +4,8 @@
 #ifndef SERVER_H
 #define SERVER_H
 
-#include "../app.h"
-#include "main.h"
+#include <common.h>
+
 int  process_server_command(char *line, int l_len, app_t *app);
 void ask_register(params_t *params, char *email);
 void server_send_string(query_args_t *q, const char *fmt, ...);
diff --git a/src/main.c b/src/main.c
index 847b872..701fbec 100644
--- a/src/main.c
+++ b/src/main.c
@@ -14,12 +14,10 @@
 #include <widget.h>
 #include <windows.h>
 
-#include "../app.h"
+#include <core/app.h>
 #include "alert.h"
-#include "connection.h"
-// #include "file_list.h"
-#include "main.h"
-#include "query.h"
+#include <core/connection.h>
+#include <core/query.h>
 
 int32_t m_id = 0;
 
diff --git a/src/main.h b/src/main.h
index 0c2f53b..8ff61a9 100644
--- a/src/main.h
+++ b/src/main.h
@@ -9,129 +9,4 @@
 #include <stddef.h>
 #include <stdint.h>
 
-#define LOCAL_PORT 1999
-#define SERVER_PORT 2000
-#define LISTEN_QLEN 32
-#define INBUFSIZE 1024
-#define DOWNLOADS_DIR "./Downloads"
-#define DIALOGUE_TITLE 64
-#define DIALOGUE_TEXT 4096
-#define INPUT_TEXT DIALOGUE_TITLE
-#define PACKAGE_SIZE INBUFSIZE * 10
-
-typedef struct params {
-  unsigned short port;
-  unsigned addr;
-  char *uname;
-  char *pass;
-  char privileges;
-  int32_t sd;
-  int32_t is_connected : 1;
-} params_t;
-
-enum state {
-  /* TUI-based */
-  S_N_D,
-  S_ASK_SEVER_IP,
-  S_ASK_LOGIN_TYPE,
-  S_ASK_LOGIN_USER,
-  S_ASK_REGISTER,
-  S_WAIT_SERVER,
-  S_PREP_SERVER_MESSAGE,
-  S_PRINT_SERVER_MESSAGE,
-  S_FILE_LIST,
-  S_WAIT_PASS,
-  /* S_FILE_SELECT, */
-  S_DOWNLOAD_FILE,
-  S_UPLOAD_PARAMS,
-  S_UPLOAD_FILE,
-  /* S_UPLOAD_FILE_SELECT, */
-  S_UPLOAD_REQUESTED,
-  S_UPLOAD_SERVER_FINISHES,
-  S_ASK_USER_BEFORE_LOGIN,
-  S_ERR,
-  S_NEXT_ACTION,
-  S_WAIT_REGISTER_CONFIRMATION,
-  S_WAIT_USER_DESCRIPTION,
-  /* Legacy */
-  WAIT_SERVER_INIT,
-  WAIT_SERVER,
-  WAIT_REGISTER,
-  WAIT_REGISTER_CONFIRMATION,
-  WAIT_CLIENT,
-};
-
-enum package_signal { sig_continue, sig_cancel, sig_finish, sig_pause };
-
-typedef struct {
-  enum package_signal signal;
-  size_t package_size;
-} s_file_pd_t; /* file package descriptor */
-
-typedef struct p_file {
-  char *name;
-  char *path;
-  char *description;
-  size_t size;
-  size_t rest;
-  size_t package_rest;
-  int32_t it_count;
-  size_t it_interval;
-  enum package_signal signal;
-  int fd;
-} p_file_t;
-
-typedef struct fl_item {
-  size_t size;
-  char *name;
-  char *description;
-  char *owner;
-  struct fl_item *next;
-} fl_item_t;
-
-typedef struct file_args {
-  int file_d;
-  fl_item_t f_selected;
-  fl_item_t *l_start;
-  fl_item_t *l_current;
-} file_args_t;
-
-enum main_window_type {
-  mw_fl_server, /* file list on the server */
-  mw_fl_local,  /* local file list */
-  mw_f_desc,    /* file description */
-};
-
-typedef void(draw_f_t)(void *fui);
-
-typedef struct main_window {
-  enum main_window_type type;
-  void *ui; /* structure which describes window UI */
-  int32_t (*cb_b_press)(void *app, void *args); /* callback on button press */
-  void (*cb_ui_refresh)(void *app);             /* refresh callback */
-  void (*reset)(void *app); /* function to reset the state of the window */
-  draw_f_t *draw;
-  struct action_key *b_keys;
-  int32_t b_keys_len;
-} main_window_t;
-
-typedef struct query_args {
-  int32_t sd;
-  int32_t buf_used;
-  p_file_t *file;
-  enum state state;
-  char buf[INBUFSIZE];
-  bool from_server;
-  params_t *params;
-  struct {
-    char *text;
-    int32_t capacity;
-    int32_t size;
-  } server_message;
-  main_window_t *main_ui;
-  void *progress_bar;
-  void *active_dialogue;
-  void *notification;
-} query_args_t;
-
 #endif
\ No newline at end of file
diff --git a/src/modals/CMakeLists.txt b/src/modals/CMakeLists.txt
index 026bb6f..919a6b2 100644
--- a/src/modals/CMakeLists.txt
+++ b/src/modals/CMakeLists.txt
@@ -2,13 +2,13 @@ add_library(modals STATIC)
 
 file(GLOB M_SOURCES "*.c")
 
-target_link_directories(modals 
-    PRIVATE 
-        "../widget/" 
-        "../widget_core/" 
-        "../lib/" 
-        "../utils/"
-)
+# target_link_directories(modals 
+#     PRIVATE 
+#         "../widget/" 
+#         "../widget_core/" 
+#         "../lib/" 
+#         "../utils/"
+# )
 
 target_link_libraries(modals 
     PRIVATE 
@@ -16,6 +16,8 @@ target_link_libraries(modals
         widget_core 
         bstring
         utils
+        common
+        windows
 )
 
 target_sources(modals
diff --git a/src/modals/ask_server_addr.c b/src/modals/ask_server_addr.c
index 19b83a7..ff86a30 100644
--- a/src/modals/ask_server_addr.c
+++ b/src/modals/ask_server_addr.c
@@ -4,7 +4,8 @@
 #include <ncursesw/ncurses.h>
 #include <widget.h>
 #include <widget_core.h>
-#include "../connection.h"
+#include <core/connection.h>
+#include <core/app.h>
 #include "group.h"
 
 typedef struct {
diff --git a/src/modals/load_pr.c b/src/modals/load_pr.c
index 1ffd835..c25f515 100644
--- a/src/modals/load_pr.c
+++ b/src/modals/load_pr.c
@@ -1,15 +1,15 @@
-#include "../server.h"
-#include "../windows/file_list.h"
-#include "alert.h"
-#include "dialogue.h"
-#include "group.h"
-#include "utils.h"
+#include <core/server.h>
+#include <windows/file_list.h>
 #include <ncursesw/ncurses.h>
 #include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <widget.h>
 
+#include "alert.h"
+#include "dialogue.h"
+#include "group.h"
+
 void dwn_pr_modal_cb(w_cb_args_t *args) {
   /* only cancel action */
   int32_t key = *((int32_t *)args->data);
diff --git a/src/modals/login_credentials.c b/src/modals/login_credentials.c
index 6c42b41..5241b22 100644
--- a/src/modals/login_credentials.c
+++ b/src/modals/login_credentials.c
@@ -6,7 +6,8 @@
 #include <unistd.h>
 
 #include <widget.h>
-#include "../server.h"
+#include <core/server.h>
+#include <core/app.h>
 
 typedef struct {
   w_button_t *element;
diff --git a/src/modals/login_option.c b/src/modals/login_option.c
index aef2501..fd45d61 100644
--- a/src/modals/login_option.c
+++ b/src/modals/login_option.c
@@ -6,7 +6,8 @@
 
 #include <unistd.h>
 #include <widget.h>
-#include "../server.h"
+#include <core/app.h>
+#include <core/server.h>
 
 typedef struct {
   w_button_t *element;
diff --git a/src/modals/register.c b/src/modals/register.c
index 78a828f..70f2536 100644
--- a/src/modals/register.c
+++ b/src/modals/register.c
@@ -8,7 +8,7 @@
 
 #include "alert.h"
 #include "group.h"
-#include "../server.h"
+#include <core/server.h>
 
 typedef struct {
   w_button_t *element;
diff --git a/src/modals/upload_props_dialogue.c b/src/modals/upload_props_dialogue.c
index 7888ee5..9db8eb0 100644
--- a/src/modals/upload_props_dialogue.c
+++ b/src/modals/upload_props_dialogue.c
@@ -1,15 +1,14 @@
-#include "checkbox.h"
-#include "group.h"
-#include "widget_core.h"
 #include <ncursesw/ncurses.h>
 #include <stdint.h>
-#include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
+#include <stdlib.h>
+
 #include <utils.h>
 #include <widget.h>
-
-#include "../server.h"
+#include <core/server.h>
+#include "checkbox.h"
+#include "group.h"
 
 void upload_props_dialogue_modal_cb(w_cb_args_t *args) {
   w_cb_args_t d_args;
diff --git a/src/widget/CMakeLists.txt b/src/widget/CMakeLists.txt
index ddc5b95..5440794 100644
--- a/src/widget/CMakeLists.txt
+++ b/src/widget/CMakeLists.txt
@@ -7,6 +7,8 @@ target_link_libraries(widget
         bstring
         widget_core
         utils
+        common
+        core
 )
 
 target_sources(widget
diff --git a/src/widget/alert.c b/src/widget/alert.c
index ffb6d53..0988b0d 100644
--- a/src/widget/alert.c
+++ b/src/widget/alert.c
@@ -1,6 +1,6 @@
 #include "alert.h"
 #include "dialogue.h"
-#include "widget_core.h"
+#include <core/app.h>
 #include <ncursesw/ncurses.h>
 #include <stdarg.h>
 #include <stdint.h>
diff --git a/src/widget/alert.h b/src/widget/alert.h
index 9a20b65..331c82a 100644
--- a/src/widget/alert.h
+++ b/src/widget/alert.h
@@ -1,8 +1,9 @@
 #ifndef W_ALERT_H
 #define W_ALERT_H
 
-#include "../app.h"
+#include <common.h>
 #include <stdarg.h>
+#include <stdbool.h>
 
 void w_alert_init(app_t *app);
 void w_alert(const char *message);
diff --git a/src/widget/button.c b/src/widget/button.c
index 4202ef3..4791e73 100644
--- a/src/widget/button.c
+++ b/src/widget/button.c
@@ -8,7 +8,8 @@
 
 #include <widget_core.h>
 #include "button.h"
-#include "../app.h"
+
+#include <core/app.h>
 
 w_button_t *init_button(WINDOW **win, w_t *w_parent, char *label) {
   w_button_t *btn = malloc(sizeof(w_button_t));
diff --git a/src/widget/checkbox.c b/src/widget/checkbox.c
index c9c9f39..cc37bf6 100644
--- a/src/widget/checkbox.c
+++ b/src/widget/checkbox.c
@@ -6,7 +6,7 @@
 #include <stdlib.h>
 #include <string.h>
 
-#include "../app.h"
+#include <core/app.h>
 #include "checkbox.h"
 #include <widget_core.h>
 
diff --git a/src/widget/dialogue.c b/src/widget/dialogue.c
index 990c2fb..6f5af3b 100644
--- a/src/widget/dialogue.c
+++ b/src/widget/dialogue.c
@@ -11,6 +11,7 @@
 #include <wchar.h>
 #include <widget.h>
 #include <widget_core.h>
+#include <core/app.h>
 
 static void (*active_callback_backup)(w_cb_args_t *) = NULL;
 
diff --git a/src/widget/dialogue.h b/src/widget/dialogue.h
index a98c6da..39f3432 100644
--- a/src/widget/dialogue.h
+++ b/src/widget/dialogue.h
@@ -4,31 +4,14 @@
 #ifndef W_DIALOGUE_H
 #define W_DIALOGUE_H
 
-#include "../common.h"
-#include "group.h"
+#include <common.h>
 #include <ncursesw/ncurses.h>
 #include <stdint.h>
 #include <utils.h>
 #include <widget_core.h>
+
 #define MAX_IDS 64
 
-enum w_dialogue_color_scheme { dc_normal, dc_alert };
-
-typedef struct {
-  w_t w;
-  WINDOW *win;
-  w_group_t *g_content;
-  w_group_t *g_action;
-  w_g_el_t *active_el;
-  char text[DIALOGUE_TEXT];
-  bool is_initiated;
-  bool needs_update;
-  bool needs_destroy;
-  coordinates_t *p_coordinates;
-  enum w_dialogue_color_scheme color_scheme;
-  d_array_ptr_t id_map;
-} w_dialogue_t;
-
 void    w_dialogue_init(w_dialogue_t *d, const char title[], const char text[],
                    coordinates_t *p_coordinates);
 void    w_dialogue_vinit(w_dialogue_t *dialogue, const char title[],
diff --git a/src/widget/group.h b/src/widget/group.h
index 418f25d..06eb9c2 100644
--- a/src/widget/group.h
+++ b/src/widget/group.h
@@ -7,28 +7,7 @@
 #include <stdint.h>
 #include <utils.h>
 #include <widget_core.h>
-
-typedef struct group_el_init_t {
-  enum w_type type;
-  bool is_default;
-  bool is_hidden_value;
-  char label[DIALOGUE_TITLE];
-  int32_t length;
-  enum w_g_dir direction;
-  union {
-    int32_t num;
-  } val;
-  struct group_el_init_t *children;
-} w_group_el_init_t;
-
-typedef struct group_t {
-  w_t w;
-  w_g_el_t *elements;
-  enum w_g_dir direction;
-  int32_t count;
-  int32_t first_id, last_id;
-  struct group_t *parent_group;
-} w_group_t;
+#include <common.h>
 
 w_group_t *w_group_init(WINDOW **win, w_t *w_parent, w_group_el_init_t *children,
                     d_array_ptr_t *id_map, enum w_g_dir dir,
diff --git a/src/widget/input.c b/src/widget/input.c
index 38c9f84..969f67e 100644
--- a/src/widget/input.c
+++ b/src/widget/input.c
@@ -6,7 +6,8 @@
 #include <stdlib.h>
 #include <string.h>
 
-#include "../app.h"
+#include <core/app.h>
+#include <utils.h>
 #include "input.h"
 #include <wchar.h>
 #include <widget_core.h>
diff --git a/src/widget/input.h b/src/widget/input.h
index aa9fde5..6499a48 100644
--- a/src/widget/input.h
+++ b/src/widget/input.h
@@ -4,7 +4,6 @@
 #ifndef W_INPUT_H
 #define W_INPUT_H
 
-#include "../main.h"
 #include <stdint.h>
 #include <widget_core.h>
 
diff --git a/src/widget/progress_bar.c b/src/widget/progress_bar.c
index faf43ca..1ce0390 100644
--- a/src/widget/progress_bar.c
+++ b/src/widget/progress_bar.c
@@ -2,7 +2,7 @@
 /* Copyright (c) 2026 Oleksandr Zhylin */
 
 #include "progress_bar.h"
-#include "../app.h"
+#include <core/app.h>
 #include <ncursesw/ncurses.h>
 #include <stdint.h>
 #include <stdlib.h>
diff --git a/src/widget_core/CMakeLists.txt b/src/widget_core/CMakeLists.txt
index 330d1f4..f627020 100644
--- a/src/widget_core/CMakeLists.txt
+++ b/src/widget_core/CMakeLists.txt
@@ -5,6 +5,7 @@ file(GLOB M_SOURCES "*.c")
 target_link_libraries(widget_core 
     PRIVATE
         utils
+        common
 )
 
 target_sources(widget_core
diff --git a/src/widget_core/widget_core.c b/src/widget_core/widget_core.c
index 272ee4f..b657492 100644
--- a/src/widget_core/widget_core.c
+++ b/src/widget_core/widget_core.c
@@ -6,7 +6,6 @@
   so it is separated from the widget directory */
 
 #include "widget_core.h"
-#include "../main.h"
 #include <ncursesw/ncurses.h>
 #include <stddef.h>
 #include <stdint.h>
diff --git a/src/widget_core/widget_core.h b/src/widget_core/widget_core.h
index 9a676dd..96f8d3a 100644
--- a/src/widget_core/widget_core.h
+++ b/src/widget_core/widget_core.h
@@ -4,104 +4,9 @@
 #ifndef WIDGET_CORE_H
 #define WIDGET_CORE_H
 
-#include "../main.h"
 #include <ncursesw/ncurses.h>
 #include <stdint.h>
-
-enum w_g_type { g_content, g_action };
-
-enum w_g_dir {
-  horizontal,
-  vertical,
-};
-
-enum w_type {
-  w_end,
-  w_button,
-  w_box,
-  w_group,
-  w_input,
-  w_checkbox,
-  w_progress,
-};
-
-enum w_val_type {
-  val_num,
-  val_ptr,
-  val_nul,
-};
-
-struct w_val_t {
-  enum w_val_type type;
-  union {
-    void *ptr;
-    int32_t num;
-  } val;
-};
-
-typedef struct {
-  int32_t id;
-  int32_t idx; /* element index in the group */
-  void *element;
-  enum w_type type;
-  enum w_g_type g_type;
-  bool is_default;
-  struct w_val_t val;
-} w_g_el_t;
-
-/* widget callback response code */
-enum w_cbrp_code {
-  cbrc_none, /* default */
-  cbrp_val,
-  cbrp_g_el, /* element of type group_el_t */
-  cbrp_err
-};
-
-/* widget callback response data */
-typedef struct {
-  enum w_cbrp_code code;
-  struct w_val_t val;
-} w_cbrp_data;
-
-typedef struct {
-  void *app;
-  void *element;
-  void *data;
-  w_cbrp_data resp_data;
-  void *active_el;
-} w_cb_args_t;
-
-typedef void (*w_cb_t)(w_cb_args_t *args);
-typedef int32_t (*w_cb_press_t)(void *app, void *data);
-
-typedef struct w_t {
-  int32_t id;
-  char title[DIALOGUE_TITLE];
-  struct {
-    int32_t y;
-    int32_t x;
-  } cur; /* cursor position */
-  struct {
-    int32_t y;
-    int32_t x;
-  } sz; /* size */
-  struct {
-    int32_t y;
-    int32_t x;
-  } m; /* margin (relative to the parent) */
-  struct {
-    int32_t y;
-    int32_t x;
-  } ps; /* position (relative to the window) */
-  WINDOW *const *parent_win;
-  struct w_t *w_parent;
-  w_cb_t callback;
-} w_t;
-
-enum w_pmt_attrs {
-  PMT_POS_CENTER = 01,
-  PMT_ALIGN_CENTER = 03,
-};
+#include <common.h>
 
 void w_init(w_t *w, w_t *w_parent, WINDOW **win, char *title);
 int32_t w_get_max_line_len(const char *text, int32_t *line_count);
diff --git a/src/windows/CMakeLists.txt b/src/windows/CMakeLists.txt
index ea2e816..8eb3739 100644
--- a/src/windows/CMakeLists.txt
+++ b/src/windows/CMakeLists.txt
@@ -2,13 +2,13 @@ add_library(windows STATIC)
 
 file(GLOB M_SOURCES "*.c")
 
-target_link_directories(windows 
-    PRIVATE 
-        "../widget/" 
-        "../widget_core/" 
-        "../lib/" 
-        "../utils/"
-)
+# target_link_directories(windows 
+#     PRIVATE 
+#         "../widget/" 
+#         "../widget_core/" 
+#         "../lib/" 
+#         "../utils/"
+# )
 
 target_link_libraries(windows 
     PRIVATE
@@ -16,6 +16,8 @@ target_link_libraries(windows
         widget_core
         bstring
         utils
+        core
+        common
 )
 
 target_sources(windows
diff --git a/src/windows/file_list.c b/src/windows/file_list.c
index 89230cc..682f3f9 100644
--- a/src/windows/file_list.c
+++ b/src/windows/file_list.c
@@ -2,10 +2,8 @@
 /* Copyright (c) 2026 Oleksandr Zhylin */
 
 #include "file_list.h"
-#include "../app.h"
-#include "../file_processor.h"
-#include "../fs.h"
-#include "../server.h"
+#include <common.h>
+#include <core.h>
 #include "main_window.h"
 #include <bstrlib.h>
 #include <ncursesw/ncurses.h>
diff --git a/src/windows/file_list.h b/src/windows/file_list.h
index 6f833ee..2b47eb5 100644
--- a/src/windows/file_list.h
+++ b/src/windows/file_list.h
@@ -4,7 +4,6 @@
 #ifndef W_FILE_LIST_H
 #define W_FILE_LIST_H
 
-#include "../app.h"
 #include <bstrlib.h>
 #include <stdint.h>
 #include <widget_core.h>
diff --git a/src/windows/fs_file_list.c b/src/windows/fs_file_list.c
index 0c673e5..f44dd12 100644
--- a/src/windows/fs_file_list.c
+++ b/src/windows/fs_file_list.c
@@ -15,9 +15,11 @@
 #include <unistd.h>
 #include <utils.h>
 
-#include "../file_processor.h"
-#include "../fs.h"
-#include "../server.h"
+#include <core/file_processor.h>
+#include <core/fs.h>
+#include <core/server.h>
+#include <core/app.h>
+
 #include "alert.h"
 #include "fs_file_list.h"
 #include "main_window.h"
diff --git a/src/windows/fs_file_list.h b/src/windows/fs_file_list.h
index 5503b3a..cc326ff 100644
--- a/src/windows/fs_file_list.h
+++ b/src/windows/fs_file_list.h
@@ -4,7 +4,6 @@
 #ifndef W_LFL_H /* LOCAL FILE LIST */
 #define W_LFL_H
 
-#include "../app.h"
 #include <stddef.h>
 #include <widget_core.h>
 #include <ncursesw/ncurses.h>
diff --git a/src/windows/main_window.c b/src/windows/main_window.c
index 7031ec3..9dd00d3 100644
--- a/src/windows/main_window.c
+++ b/src/windows/main_window.c
@@ -6,6 +6,9 @@
 #include "fs_file_list.h"
 #include "text_edit.h"
 
+#include <core/app.h>
+#include <widget/dialogue.h>
+
 void main_window_set(app_t *app, enum main_window_type type) {
   if (app->main_ui.ui != NULL) {
     main_window_destroy(app);
diff --git a/src/windows/main_window.h b/src/windows/main_window.h
index e1b05aa..ff6e3a9 100644
--- a/src/windows/main_window.h
+++ b/src/windows/main_window.h
@@ -4,7 +4,7 @@
 #ifndef MAIN_WINDOW_H
 #define MAIN_WINDOW_H
 
-#include "../app.h"
+#include <common.h>
 
 void main_window_set(app_t *app, enum main_window_type type);
 void main_window_draw(app_t *app);
diff --git a/src/windows/text_edit.c b/src/windows/text_edit.c
index 089f1c8..b4f314f 100644
--- a/src/windows/text_edit.c
+++ b/src/windows/text_edit.c
@@ -1,9 +1,6 @@
 /* SPDX-License-Identifier: MIT */
 /* Copyright (c) 2026 Oleksandr Zhylin */
 
-#include "../file_processor.h"
-#include "../server.h"
-#include "../windows/main_window.h"
 #include <dirent.h>
 #include <fcntl.h>
 #include <ncursesw/ncurses.h>
@@ -17,10 +14,15 @@
 #include <utils.h>
 #include <wchar.h>
 
+#include <core/file_processor.h>
+#include <core/server.h>
+#include <core/app.h>
+
 #include "d_array.h"
 #include "file_list.h"
 #include "text_edit.h"
 #include "widget_core.h"
+#include "main_window.h"
 
 /* TODO: расширять capacity линии при достижении лимита */
 
diff --git a/src/windows/text_edit.h b/src/windows/text_edit.h
index eaa0468..a22e8ec 100644
--- a/src/windows/text_edit.h
+++ b/src/windows/text_edit.h
@@ -4,7 +4,6 @@
 #ifndef W_TEXT_EDIT_H /* LOCAL FILE LIST */
 #define W_TEXT_EDIT_H
 
-#include "../app.h"
 #include <ncursesw/ncurses.h>
 #include <stddef.h>
 #include <stdint.h>