cmake_minimum_required(VERSION 3.12.0)
include(FindPkgConfig REQUIRED)

if(DEFINED ENV{PETSC_DIR})
    message("PETSC_DIR:\n$ENV{PETSC_DIR}\n")
else()
    message(FATAL_ERROR "PETSc location (PETSC_DIR) is not defined")
endif()

# Dummy project to determine compiler names and version
project(Prerequisites LANGUAGES)
set(ENV{PKG_CONFIG_PATH} "$ENV{PETSC_DIR}/$ENV{PETSC_ARCH}/lib/pkgconfig:$ENV{PKG_CONFIG_PATH}")
pkg_check_modules(PETSC_MIN REQUIRED PETSc>=3.12.0 QUIET) #CMake does not support version range
pkg_check_modules(PETSC REQUIRED PETSc<3.21.0)

pkg_get_variable(CMAKE_Fortran_COMPILER PETSc fcompiler)
pkg_get_variable(CMAKE_C_COMPILER PETSc ccompiler)

# Solver determines name of project
string(TOUPPER "${DAMASK_SOLVER}" DAMASK_SOLVER_UPPER)
string(TOLOWER "${DAMASK_SOLVER}" DAMASK_SOLVER_LOWER)
if("${DAMASK_SOLVER_UPPER}" MATCHES "^(GRID|MESH|TEST)$")
    project("damask-${DAMASK_SOLVER_LOWER}" HOMEPAGE_URL https://damask.mpie.de LANGUAGES Fortran C)
else()
    message(FATAL_ERROR "Invalid solver: DAMASK_SOLVER=${DAMASK_SOLVER}")
endif()
add_definitions("-D${DAMASK_SOLVER_UPPER}")

set(CMAKE_Fortran_PREPROCESS "ON") # works only for CMake >= 3.18

# EXPERIMENTAL: This might help to detect HDF5 and FFTW3 in the future if PETSc is not aware of them
set(ENV{PKG_CONFIG_PATH} "$ENV{PETSC_DIR}/$ENV{PETSC_ARCH}/externalpackages:$ENV{PKG_CONFIG_PATH}")
pkg_check_modules(HDF5 hdf5)
pkg_check_modules(FFTW3 fftw3)
pkg_check_modules(fYAML libfyaml)
pkg_check_modules(zlib zlib)

file(STRINGS ${PROJECT_SOURCE_DIR}/VERSION DAMASK_VERSION)

message("\nBuilding ${CMAKE_PROJECT_NAME} ${DAMASK_VERSION}\n")

add_definitions(-DPETSC)
add_definitions(-DDAMASKVERSION="${DAMASK_VERSION}")
add_definitions(-DCMAKE_SYSTEM="${CMAKE_SYSTEM}")
if(PETSC_VERSION VERSION_EQUAL 3.17.0)
   add_definitions("-DCHKERRQ=PetscCall")
endif()

if(CMAKE_BUILD_TYPE STREQUAL "")
    set(CMAKE_BUILD_TYPE "RELEASE")
endif()
string(TOUPPER "${CMAKE_BUILD_TYPE}" CMAKE_BUILD_TYPE)

# Predefined sets for OPTIMIZATION/OPENMP based on BUILD_TYPE
if(CMAKE_BUILD_TYPE STREQUAL "DEBUG" OR CMAKE_BUILD_TYPE STREQUAL "SYNTAXONLY")
    set(DEBUG_FLAGS "${DEBUG_FLAGS} -DDEBUG")
    set(PARALLEL "OFF")
    set(OPTI "DEBUG")
elseif(CMAKE_BUILD_TYPE STREQUAL "RELEASE")
    set(PARALLEL "ON")
    set(OPTI "DEFENSIVE")
elseif(CMAKE_BUILD_TYPE STREQUAL "DEBUGRELEASE")
    set(DEBUG_FLAGS "${DEBUG_FLAGS} -DDEBUG")
    set(PARALLEL "ON")
    set(OPTI "DEFENSIVE")
elseif(CMAKE_BUILD_TYPE STREQUAL "PERFORMANCE")
    set(PARALLEL "ON")
    set(OPTI "AGGRESSIVE")
else()
    message(FATAL_ERROR "Invalid build type: CMAKE_BUILD_TYPE=${CMAKE_BUILD_TYPE}")
endif()

# $OPTIMIZATION takes precedence over $BUILD_TYPE defaults
if(OPTIMIZATION STREQUAL "" OR NOT DEFINED OPTIMIZATION)
    set(OPTIMIZATION "${OPTI}")
else()
    set(OPTIMIZATION "${OPTIMIZATION}")
endif()

# $OPENMP takes precedence over $BUILD_TYPE defaults
if(OPENMP STREQUAL "" OR NOT DEFINED OPENMP)
    set(OPENMP "${PARALLEL}")
else()
    set(OPENMP "${OPENMP}")
endif()

# syntax check only(mainly for pre-receive hook)
if(CMAKE_BUILD_TYPE STREQUAL "SYNTAXONLY")
    set(BUILDCMD_POST "${BUILDCMD_POST} -fsyntax-only")
endif()


if   (CMAKE_Fortran_COMPILER_ID STREQUAL "GNU")
    set(Fortran_COMPILER_VERSION_MIN 9.1)
elseif(CMAKE_Fortran_COMPILER_ID STREQUAL "Intel")
    set(Fortran_COMPILER_VERSION_MIN 19)
elseif(CMAKE_Fortran_COMPILER_ID STREQUAL "IntelLLVM")
    set(Fortran_COMPILER_VERSION_MIN 19)
elseif(CMAKE_Fortran_COMPILER_ID STREQUAL "LLVMFlang")
    set(Fortran_COMPILER_VERSION_MIN 19)
else()
    message(FATAL_ERROR "Compiler '${CMAKE_Fortran_COMPILER_ID}' not supported")
endif()
if(CMAKE_Fortran_COMPILER_VERSION VERSION_LESS Fortran_COMPILER_VERSION_MIN)
    message(FATAL_ERROR "Version '${CMAKE_Fortran_COMPILER_VERSION}' of '${CMAKE_Fortran_COMPILER_ID}' is not supported")
endif()

list(APPEND CMAKE_MODULE_PATH ${PROJECT_SOURCE_DIR}/cmake)
include("Compiler-${CMAKE_Fortran_COMPILER_ID}")

file(STRINGS "$ENV{PETSC_DIR}/$ENV{PETSC_ARCH}/lib/petsc/conf/petscvariables" PETSC_EXTERNAL_LIB REGEX "PETSC_EXTERNAL_LIB_BASIC = .*$?")
string(REPLACE "PETSC_EXTERNAL_LIB_BASIC = " "" PETSC_EXTERNAL_LIB "${PETSC_EXTERNAL_LIB}")
message("PETSC_EXTERNAL_LIB:\n${PETSC_EXTERNAL_LIB}\n")

file(STRINGS "$ENV{PETSC_DIR}/$ENV{PETSC_ARCH}/lib/petsc/conf/petscvariables" PETSC_INCLUDES REGEX "PETSC_FC_INCLUDES = .*$?")
string(REPLACE "PETSC_FC_INCLUDES = " "" PETSC_INCLUDES "${PETSC_INCLUDES}")
message("PETSC_INCLUDES:\n${PETSC_INCLUDES}\n")

set(CMAKE_Fortran_FLAGS_${CMAKE_BUILD_TYPE} "${BUILDCMD_PRE} ${OPENMP_FLAGS} ${STANDARD_CHECK} ${OPTIMIZATION_FLAGS} ${COMPILE_FLAGS}")
set(CMAKE_Fortran_LINK_EXECUTABLE           "${BUILDCMD_PRE} ${CMAKE_Fortran_COMPILER} ${OPENMP_FLAGS} ${OPTIMIZATION_FLAGS} ${LINKER_FLAGS}")

if(CMAKE_BUILD_TYPE STREQUAL "DEBUG")
    set(CMAKE_Fortran_FLAGS_${CMAKE_BUILD_TYPE} "${CMAKE_Fortran_FLAGS_${CMAKE_BUILD_TYPE}} ${DEBUG_FLAGS}")
    set(CMAKE_Fortran_LINK_EXECUTABLE           "${CMAKE_Fortran_LINK_EXECUTABLE} ${DEBUG_FLAGS}")
endif()

set(CMAKE_Fortran_FLAGS_${CMAKE_BUILD_TYPE} "${CMAKE_Fortran_FLAGS_${CMAKE_BUILD_TYPE}} ${PETSC_INCLUDES} ${BUILDCMD_POST}")

set(CMAKE_Fortran_LINK_EXECUTABLE "${CMAKE_Fortran_LINK_EXECUTABLE} <OBJECTS> -o <TARGET> <LINK_LIBRARIES> -L${PETSC_LIBRARY_DIRS} -lpetsc ${PETSC_EXTERNAL_LIB} -lz")

if(fYAML_FOUND STREQUAL "1")
    set(CMAKE_Fortran_LINK_EXECUTABLE "${CMAKE_Fortran_LINK_EXECUTABLE} -L${fYAML_LIBRARY_DIRS}")
    foreach(fYAML_LIBRARY ${fYAML_LIBRARIES})
        set(CMAKE_Fortran_LINK_EXECUTABLE "${CMAKE_Fortran_LINK_EXECUTABLE} -L${fYAML_LIBRARY_DIRS} -l${fYAML_LIBRARY}")
    endforeach()
    add_definitions(-DFYAML)
    pkg_get_variable(fYAML_INCLUDE_DIR libfyaml includedir) # fYAML_INCLUDE_DIRS and fYAML_CFLAGS are not working
    set(CMAKE_C_FLAGS_${CMAKE_BUILD_TYPE} "${CMAKE_C_FLAGS_${CMAKE_BUILD_TYPE}} -I${fYAML_INCLUDE_DIR}")
endif()

set(CMAKE_Fortran_LINK_EXECUTABLE "${CMAKE_Fortran_LINK_EXECUTABLE} ${BUILDCMD_POST}")

message("Fortran Compiler Flags:\n${CMAKE_Fortran_FLAGS_${CMAKE_BUILD_TYPE}}\n")
message("C Compiler Flags:\n${CMAKE_C_FLAGS_${CMAKE_BUILD_TYPE}}\n")
message("Fortran Linker Command:\n${CMAKE_Fortran_LINK_EXECUTABLE}\n")

# location of code
add_subdirectory(src)