cmake_minimum_required(VERSION 3.8)
project(gsl C)

option(INSTALL_HEADERS "Install public header files" ON)

# Function to extract parameter from makefile. Space separated values are returned as lists
function(extract_from_makefile PATTERN RETURN FILEPATH)
    file(READ ${FILEPATH} MAKEFILE_CONTENT)
    string(REGEX MATCH "${PATTERN}" CONTENTS "${MAKEFILE_CONTENT}")
    set(CONTENTS ${CMAKE_MATCH_1})
    # Split string into list
    string(REGEX REPLACE "([\t ]+(\\\\\n)?)+" ";" CONTENTS "${CONTENTS}")
    string(REGEX REPLACE "[\t ]*\\\\\n[\t ]*;" "" CONTENTS "${CONTENTS}")
    if("${CONTENTS}" STREQUAL "")
        message(AUTHOR_WARNING "No match for \"${PATTERN}\" found in file ${FILEPATH}")
    endif()
    # Return 
    set(${RETURN} ${CONTENTS} PARENT_SCOPE)
endfunction(extract_from_makefile)

# Function to extract C sources from makefile
function(extract_sources SUBFOLDER ALLSOURCES)
    extract_from_makefile("lib[a-zA-Z1-9_]*_la_SOURCES[ \t]*=[ \t]*(((\\\\\n)?[^\n])*)" SOURCEFILES "${SUBFOLDER}/Makefile.am")
    # Add the folder in front of the file names 
    string(REGEX REPLACE "([^;]+)" "${SUBFOLDER}/\\1" SOURCEFILES "${SOURCEFILES}")
    # Return 
    set(${ALLSOURCES} ${${ALLSOURCES}} ${SOURCEFILES} PARENT_SCOPE)
endfunction(extract_sources)

set(SOURCES)
set(CBLAS_SOURCES)
extract_from_makefile("SUBDIRS = (((\\\\\n)?[^\n])*)" FOLDERS "./Makefile.am")
extract_sources("." SOURCES)
foreach(DIR IN LISTS FOLDERS)
    if("${DIR}" STREQUAL "cblas")
        extract_sources("${DIR}" CBLAS_SOURCES)
    else()
        extract_sources("${DIR}" SOURCES)
    endif()
endforeach()

file(READ gsl_types.h GSLTYPES_H)
string(REPLACE "#ifdef WIN32" "#if 1 /*WIN32*/" GSLTYPES_H "${GSLTYPES_H}")
if(BUILD_SHARED_LIBS)
    string(REPLACE "#  ifdef GSL_DLL" "#  if 1 /*GSL_DLL*/" GSLTYPES_H "${GSLTYPES_H}")
endif()
file(WRITE ${CMAKE_CURRENT_BINARY_DIR}/gsl_types.h "${GSLTYPES_H}")

file(GLOB_RECURSE PUBLIC_HEADERS gsl*.h)
list(APPEND PUBLIC_HEADERS ${CMAKE_CURRENT_BINARY_DIR}/gsl_types.h)

# The debug libraries have a "d" postfix so that CMake's FindGSL.cmake 
# module can distinguish between Release and Debug libraries
set(CMAKE_DEBUG_POSTFIX "d")

add_library(gslcblas ${CBLAS_SOURCES})
set_target_properties(gslcblas PROPERTIES WINDOWS_EXPORT_ALL_SYMBOLS ON)

add_library(gsl ${SOURCES})
set_target_properties(gsl PROPERTIES DEFINE_SYMBOL DLL_EXPORT WINDOWS_EXPORT_ALL_SYMBOLS ON)
target_link_libraries(gsl PUBLIC gslcblas)


if(INSTALL_HEADERS)
    set_target_properties(gsl PROPERTIES PUBLIC_HEADER "${PUBLIC_HEADERS}")
endif()
target_include_directories(gslcblas PRIVATE ${CMAKE_CURRENT_BINARY_DIR} ${CMAKE_CURRENT_SOURCE_DIR})
target_include_directories(gsl PRIVATE ${CMAKE_CURRENT_BINARY_DIR} ${CMAKE_CURRENT_SOURCE_DIR})
# For the build, we need to copy all headers to the gsl directory
file(MAKE_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}/gsl)
file(COPY ${PUBLIC_HEADERS} DESTINATION "${CMAKE_CURRENT_BINARY_DIR}/gsl")

set(TARGET_INSTALL_OPTIONS)
if(INSTALL_HEADERS)
    set(TARGET_INSTALL_OPTIONS PUBLIC_HEADER DESTINATION include/gsl)
endif()

configure_file("${CMAKE_CURRENT_SOURCE_DIR}/gsl.pc.in" "${CMAKE_CURRENT_BINARY_DIR}/gsl.pc" @ONLY)
install(FILES "${CMAKE_CURRENT_BINARY_DIR}/gsl.pc" DESTINATION "${CMAKE_INSTALL_LIBDIR}/pkgconfig")

install(TARGETS gsl gslcblas
    RUNTIME DESTINATION bin
    LIBRARY DESTINATION lib
    ARCHIVE DESTINATION lib
    ${TARGET_INSTALL_OPTIONS}
)