# Tcl/Tk GUI support
option(FUN_WITH_TCLTK "Enable Tcl/Tk GUI support" OFF)
set(TCL_INCLUDE_DIRS "")
set(TCL_LINK_LIBS "")
if(FUN_WITH_TCLTK)
  add_definitions(-DFUN_WITH_TCLTK)
  find_package(PkgConfig QUIET)
  if(PKG_CONFIG_FOUND)
    pkg_check_modules(TCL QUIET tcl)
    pkg_check_modules(TK  QUIET tk)
  endif()
  if(TCL_FOUND OR TK_FOUND)
    if(TCL_FOUND)
      list(APPEND TCL_INCLUDE_DIRS ${TCL_INCLUDE_DIRS} ${TCL_INCLUDE_DIRS})
      list(APPEND TCL_LINK_LIBS ${TCL_LINK_LIBS} ${TCL_LIBRARIES})
    endif()
    if(TK_FOUND)
      list(APPEND TCL_INCLUDE_DIRS ${TCL_INCLUDE_DIRS} ${TK_INCLUDE_DIRS})
      list(APPEND TCL_LINK_LIBS ${TCL_LINK_LIBS} ${TK_LIBRARIES})
    endif()
  else()
    find_path(TCL_INCLUDE_DIR tcl.h PATH_SUFFIXES tcl8.7 tcl8.6 include)
    find_library(TCL_LIB NAMES tcl8.7 tcl8.6 tcl)
    find_library(TK_LIB  NAMES tk8.7  tk8.6  tk)
    if(TCL_INCLUDE_DIR)
      list(APPEND TCL_INCLUDE_DIRS ${TCL_INCLUDE_DIR})
    endif()
    if(TCL_LIB)
      list(APPEND TCL_LINK_LIBS ${TCL_LIB})
    endif()
    if(TK_LIB)
      list(APPEND TCL_LINK_LIBS ${TK_LIB})
    endif()
    if(APPLE)
      # macOS frameworks often unnecessary when using Homebrew tcl/tk
    elseif(WIN32)
      list(APPEND TCL_LINK_LIBS user32 gdi32 comctl32)
    else()
      find_package(X11 QUIET)
      if(X11_FOUND)
        list(APPEND TCL_INCLUDE_DIRS ${X11_INCLUDE_DIR})
        list(APPEND TCL_LINK_LIBS ${X11_LIBRARIES})
      endif()
    endif()
  endif()
endif()