cmake_minimum_required(VERSION 3.0)
project(plugins)

find_package(gazebo REQUIRED)

# Work around broken CMake exports pulled in transitively via Gazebo -> DART.
# DART was packaged with empty include prefixes, so several of its imported
# targets (Boost::system/filesystem/regex, ...) carry a bogus "/include" path
# in INTERFACE_INCLUDE_DIRECTORIES. CMake validates these while walking the
# link closure and aborts the generate step with:
#   Imported target "dart" includes non-existent path "/include".
# Recurse through the whole GAZEBO_LIBRARIES link closure and drop any include
# directory that does not exist on disk.
function(_strip_bad_includes _target)
  if(NOT TARGET ${_target})
    return()
  endif()
  get_property(_seen GLOBAL PROPERTY "_sbi_seen_${_target}")
  if(_seen)
    return()
  endif()
  set_property(GLOBAL PROPERTY "_sbi_seen_${_target}" 1)

  get_target_property(_inc ${_target} INTERFACE_INCLUDE_DIRECTORIES)
  if(_inc)
    set(_ok "")
    foreach(_p IN LISTS _inc)
      if(EXISTS "${_p}")
        list(APPEND _ok "${_p}")
      endif()
    endforeach()
    set_target_properties(${_target} PROPERTIES
      INTERFACE_INCLUDE_DIRECTORIES "${_ok}")
  endif()

  get_target_property(_deps ${_target} INTERFACE_LINK_LIBRARIES)
  if(_deps)
    foreach(_d IN LISTS _deps)
      if(TARGET ${_d})
        _strip_bad_includes(${_d})
      endif()
    endforeach()
  endif()
endfunction()

foreach(_root IN LISTS GAZEBO_LIBRARIES)
  if(TARGET ${_root})
    _strip_bad_includes(${_root})
  endif()
endforeach()

# The same empty-prefix bug leaves a stray "/include" in GAZEBO_INCLUDE_DIRS;
# drop non-existent entries so the compiler isn't handed bogus -I flags.
set(_gz_inc_ok "")
foreach(_p IN LISTS GAZEBO_INCLUDE_DIRS)
  if(EXISTS "${_p}")
    list(APPEND _gz_inc_ok "${_p}")
  endif()
endforeach()
set(GAZEBO_INCLUDE_DIRS "${_gz_inc_ok}")

# Gazebo headers require C++14, and bring in their own compile flags.
set(CMAKE_CXX_STANDARD 14)
set(CMAKE_CXX_STANDARD_REQUIRED ON)
set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${GAZEBO_CXX_FLAGS}")

include_directories(${GAZEBO_INCLUDE_DIRS})
link_directories(${GAZEBO_LIBRARY_DIRS})

add_library(SimpleDronePlugin SHARED SimpleDronePlugin.cc)
# GAZEBO_LIBRARIES already pulls in the sensors + rendering + transport libs
# needed for reading camera frames.
target_link_libraries(SimpleDronePlugin ${GAZEBO_LIBRARIES})