Cannot build cmake project with including directories in cmake project - c++

Question

|---Engine
|----CMakeList.txt
|----Engine.cpp
|----Engine.h
|---Models
|----CMakeList.txt
|----Snake.cpp
|----Snake.hpp
|---Type
|----CMakeList.txt
|----Point.hpp
|---CMakeList.txt
|---main.cpp
I just can't tell the main sheet that I want to add a directory with files to it ...
Each time, errors of the following type appear:
CMake Error at CMakeLists.txt: 12 (target_include_directories):
Cannot specify include directories for target "Snake" which is not built by
this project.
CMake Error at CMakeLists.txt: 13 (target_link_directories):
Cannot specify link directories for target "Snake" which is not built by
this project.
CMake Error at Engine / CMakeLists.txt: 8 (target_include_directories):
Cannot specify include directories for target "Snake" which is not built by
this project.
CMake Error at CMakeLists.txt: 17 (target_link_libraries):
Cannot specify link libraries for target "Snake" which is not built by this
project.
- Configuring incomplete, errors occurred!
Which, for several hours of intensified attempts, are not corrected in any way. Can anyone help with this?
CMakeLists.txt from Engine folder:
set(HEADERS
Engine.h)
set(SOURCES
Engine.cpp)
add_library(Engine ${HEADERS} ${SOURCES})
target_include_directories(${PROJECT_NAME} PUBLIC ${CMAKE_CURRENT_LIST_DIR})
Main CMakeList.txt:
cmake_minimum_required(VERSION 3.16.3)
project(Snake)
set(CMAKE_CXX_STANDARD 17)
set(CMAKE_CXX_STANDARD_REQUIRED ON)
set(CMAKE_CXX_EXTENSIONS OFF)
set(PROJECT_SOURCES
main.cpp
)
target_include_directories(${PROJECT_NAME} PUBLIC Engine)
target_link_directories(${PROJECT_NAME} PUBLIC Engine)
add_subdirectory(Engine)
target_link_libraries(${PROJECT_NAME} Engine)
add_executable(${PROJECT_NAME}
${PROJECT_SOURCES}
)
find_package(SFML 2.5.1 COMPONENTS graphics audio REQUIRED)
include_directories(${SFML_INCLUDE_DIR})
target_link_libraries(${PROJECT_NAME} sfml-graphics sfml-audio)
set(SFML_STATIC_LIBRARIES FALSE)

Answer 1

There are two errors. The first one is to call a PROJECT_NAME that hasn't been built yet. add_executable(${PROJECT_NAME} ...) and add_library(${PROJECT_NAME ...) should be used before the target_include_directories and target_link_directories that refers to it. Because, as #Stephen Newell noted, otherwise you will be using a PROJECT NAME that hasn't been declared/built yet.
The second error is that you are calling a PROJECT_NAME inside Engine/CMakeLists. Maybe you are missing a project(...) inside of it.
Maybe you should move set(SFML_STATIC_LIBRARIES FALSE) before linking it, as well.