# Try to find gnu scientific library GSL

# See

# http://www.gnu.org/software/gsl/  and

# http://gnuwin32.sourceforge.net/packages/gsl.htm

#

# Based on a script of Felix Woelk and Jan Woetzel

# (www.mip.informatik.uni-kiel.de)

#

# It defines the following variables:

#  GSL_FOUND - system has GSL lib

#  GSL_INCLUDE_DIRS - where to find headers

#  GSL_LIBRARIES - full path to the libraries

#  GSL_LIBRARY_DIRS, the directory where the PLplot library is found.

#  CMAKE_GSL_CXX_FLAGS  = Unix compiler flags for GSL, essentially "`gsl-config --cxxflags`"

#  GSL_LINK_DIRECTORIES = link directories, useful for rpath on Unix

#  GSL_EXE_LINKER_FLAGS = rpath on Unix

INCLUDE(FindPkgConfig)

PKG_CHECK_MODULES(GSL "gsl >= 1.10")

IF(NOT GSL_FOUND)

set( GSL_FOUND OFF )

set( GSL_CBLAS_FOUND OFF )

# Windows, but not for Cygwin and MSys where gsl-config is available

if( WIN32 AND NOT CYGWIN AND NOT MSYS )

	# look for headers

  find_path( GSL_INCLUDE_DIR

    NAMES gsl/gsl_cdf.h gsl/gsl_randist.h

    )

  if( GSL_INCLUDE_DIR )

  	# look for gsl library

    find_library( GSL_LIBRARY

      NAMES gsl

    )

    if( GSL_LIBRARY )

      set( GSL_INCLUDE_DIRS ${GSL_INCLUDE_DIR} )

      get_filename_component( GSL_LIBRARY_DIRS ${GSL_LIBRARY} PATH )

      set( GSL_FOUND ON )

    endif( GSL_LIBRARY )

		# look for gsl cblas library

    find_library( GSL_CBLAS_LIBRARY

        NAMES gslcblas

      )

    if( GSL_CBLAS_LIBRARY )

      set( GSL_CBLAS_FOUND ON )

    endif( GSL_CBLAS_LIBRARY )

    set( GSL_LIBRARIES ${GSL_LIBRARY} ${GSL_CBLAS_LIBRARY} )

  endif( GSL_INCLUDE_DIR )

  #mark_as_advanced(

  #  GSL_INCLUDE_DIR

  #  GSL_LIBRARY

  #  GSL_CBLAS_LIBRARY

  #)

else( WIN32 AND NOT CYGWIN AND NOT MSYS )

  if( UNIX OR MSYS )

		find_program( GSL_CONFIG_EXECUTABLE gsl-config

			/usr/bin/

			/usr/local/bin

		)

		if( GSL_CONFIG_EXECUTABLE )

			set( GSL_FOUND ON )

      # run the gsl-config program to get cxxflags

      execute_process(

        COMMAND sh "${GSL_CONFIG_EXECUTABLE}" --cflags

        OUTPUT_VARIABLE GSL_CFLAGS

        RESULT_VARIABLE RET

        ERROR_QUIET

        )

      if( RET EQUAL 0 )

        string( STRIP "${GSL_CFLAGS}" GSL_CFLAGS )

        separate_arguments( GSL_CFLAGS )

        # parse definitions from cflags; drop -D* from CFLAGS

        string( REGEX MATCHALL "-D[^;]+"

          GSL_DEFINITIONS  "${GSL_CFLAGS}" )

        string( REGEX REPLACE "-D[^;]+;" ""

          GSL_CFLAGS "${GSL_CFLAGS}" )

        # parse include dirs from cflags; drop -I prefix

        string( REGEX MATCHALL "-I[^;]+"

          GSL_INCLUDE_DIRS "${GSL_CFLAGS}" )

        string( REPLACE "-I" ""

          GSL_INCLUDE_DIRS "${GSL_INCLUDE_DIRS}")

        string( REGEX REPLACE "-I[^;]+;" ""

          GSL_CFLAGS "${GSL_CFLAGS}")

        message("GSL_DEFINITIONS=${GSL_DEFINITIONS}")

        message("GSL_INCLUDE_DIRS=${GSL_INCLUDE_DIRS}")

        message("GSL_CFLAGS=${GSL_CFLAGS}")

      else( RET EQUAL 0 )

        set( GSL_FOUND FALSE )

      endif( RET EQUAL 0 )

      # run the gsl-config program to get the libs

      execute_process(

        COMMAND sh "${GSL_CONFIG_EXECUTABLE}" --libs

        OUTPUT_VARIABLE GSL_LIBRARIES

        RESULT_VARIABLE RET

        ERROR_QUIET

        )

      if( RET EQUAL 0 )

        string(STRIP "${GSL_LIBRARIES}" GSL_LIBRARIES )

        separate_arguments( GSL_LIBRARIES )

        # extract linkdirs (-L) for rpath (i.e., LINK_DIRECTORIES)

        string( REGEX MATCHALL "-L[^;]+"

          GSL_LIBRARY_DIRS "${GSL_LIBRARIES}" )

        string( REPLACE "-L" ""

          GSL_LIBRARY_DIRS "${GSL_LIBRARY_DIRS}" )

      else( RET EQUAL 0 )

        set( GSL_FOUND FALSE )

      endif( RET EQUAL 0 )

			MARK_AS_ADVANCED(

				GSL_CFLAGS

			)

			message( STATUS "Using GSL from ${GSL_PREFIX}" )

		else( GSL_CONFIG_EXECUTABLE )

			message( STATUS "FindGSL: gsl-config not found.")

		endif( GSL_CONFIG_EXECUTABLE )

	endif( UNIX OR MSYS )

endif( WIN32 AND NOT CYGWIN AND NOT MSYS )

if( GSL_FOUND )

  if( NOT GSL_FIND_QUIETLY )

    message( STATUS "FindGSL: Found both GSL headers and library" )

  endif( NOT GSL_FIND_QUIETLY )

else( GSL_FOUND )

  if( GSL_FIND_REQUIRED )

    message( FATAL_ERROR "FindGSL: Could not find GSL headers or library" )

  endif( GSL_FIND_REQUIRED )

endif( GSL_FOUND )

INCLUDE(FindPackageHandleStandardArgs)

FIND_PACKAGE_HANDLE_STANDARD_ARGS(GSL DEFAULT_MSG GSL_LIBRARIES GSL_INCLUDE_DIRS)

ENDIF(NOT GSL_FOUND)