# fail noisily if attempt to use this file without setting:
# cmake_minimum_required(VERSION ${CMAKE_VERSION})
# project(... LANGUAGES ...)

cmake_policy(SET CMP0000 NEW)

set(PACKAGE_FOUND FALSE)

list(REMOVE_DUPLICATES LLVM_MESON_VERSIONS)

while(TRUE)
  #Activate CMake version selection
  foreach(i IN LISTS LLVM_MESON_VERSIONS)
    find_package(LLVM ${i}
      CONFIG
      NAMES ${LLVM_MESON_PACKAGE_NAMES}
      QUIET)
    if(LLVM_FOUND)
      break()
    endif()
  endforeach()

  # ARCHS has to be set via the CMD interface
  if(LLVM_FOUND OR "${ARCHS}" STREQUAL "")
    break()
  endif()

  list(GET       ARCHS 0 CMAKE_LIBRARY_ARCHITECTURE)
  list(REMOVE_AT ARCHS 0)
endwhile()

function(meson_llvm_cmake_dynamic_available mod out)
  # Check if we can only compare LLVM_DYLIB_COMPONENTS, because
  # we do not need complex component translation logic, if all
  # is covered by one variable
  if(mod IN_LIST LLVM_DYLIB_COMPONENTS)
    set(${out} TRUE PARENT_SCOPE)
    return()
  elseif((NOT (mod IN_LIST LLVM_DYLIB_COMPONENTS))
      AND (NOT("${LLVM_DYLIB_COMPONENTS}" STREQUAL "all")))
    set(${out} FALSE PARENT_SCOPE)
    return()
  endif()

  # Complex heurisic to filter all pseudo-components and skip invalid names
  # LLVM_DYLIB_COMPONENTS will be 'all', because in other case we returned
  # in previous check. 'all' is also handled there.
  set(llvm_pseudo_components "native" "backend" "engine" "all-targets")
  is_llvm_target_specifier(${mod} mod_spec INCLUDED_TARGETS)
  string(TOUPPER "${LLVM_AVAILABLE_LIBS}" capitalized_libs)
  string(TOUPPER "${LLVM_TARGETS_TO_BUILD}" capitalized_tgts)
  if(mod_spec)
    set(${out} TRUE PARENT_SCOPE)
  elseif(mod IN_LIST capitalized_tgts)
    set(${out} TRUE PARENT_SCOPE)
  elseif(mod IN_LIST llvm_pseudo_components)
    set(${out} TRUE PARENT_SCOPE)
  elseif(LLVM${mod} IN_LIST capitalized_libs)
    set(${out} TRUE PARENT_SCOPE)
  else()
    set(${out} FALSE PARENT_SCOPE)
  endif()
endfunction()

function(is_static target ret)
  if(TARGET ${target})
    get_target_property(target_type ${target} TYPE)
    if(target_type STREQUAL "STATIC_LIBRARY")
      set(${ret} TRUE PARENT_SCOPE)
      return()
    endif()
  endif()
  set(${ret} FALSE PARENT_SCOPE)
endfunction()

# Concatenate LLVM_MESON_REQUIRED_MODULES and LLVM_MESON_OPTIONAL_MODULES
set(LLVM_MESON_MODULES ${LLVM_MESON_REQUIRED_MODULES} ${LLVM_MESON_OPTIONAL_MODULES})


# Check if LLVM exists in dynamic world
# Initialization before modules checking
if(LLVM_FOUND)
  if(LLVM_MESON_DYLIB AND TARGET LLVM)
    set(PACKAGE_FOUND TRUE)
  elseif(NOT LLVM_MESON_DYLIB)
    # Use LLVMSupport to check if static targets exist
    set(static_tg FALSE)
    is_static(LLVMSupport static_tg)
    if(static_tg)
      set(PACKAGE_FOUND TRUE)
    endif(static_tg)
  endif()
endif()

if(PACKAGE_FOUND)
  foreach(mod IN LISTS LLVM_MESON_MODULES)
    # Reset variables
    set(out_mods)
    set(real_mods)

    # Generate a lower and upper case version
    string(TOLOWER "${mod}" mod_L)
    string(TOUPPER "${mod}" mod_U)

    # Special case - "all-targets" pseudo target
    # Just append all targets, if pseudo-target exists
    if("${mod}" STREQUAL "all-targets")
      set(mod_L  ${LLVM_TARGETS_TO_BUILD})
      string(TOUPPER "${LLVM_TARGETS_TO_BUILD}" mod_U)
    endif()

    # Check if required module is linked is inside libLLVM.so.
    # If not, skip this module
    if(LLVM_MESON_DYLIB
       AND DEFINED LLVM_DYLIB_COMPONENTS)
        meson_llvm_cmake_dynamic_available(${mod} MOD_F)
        meson_llvm_cmake_dynamic_available(${mod_L} MOD_L_F)
        meson_llvm_cmake_dynamic_available(${mod_U} MOD_U_F)
        if(MOD_F OR MOD_L_F OR MOD_U_F)
          set(MESON_LLVM_TARGETS_${mod} LLVM)
        endif()
    elseif(LLVM_MESON_DYLIB AND (mod IN_LIST LLVM_MESON_REQUIRED_MODULES))
      # Dynamic was requested, but no required variables set, we cannot continue
      set(PACKAGE_FOUND FALSE)
      break()
    elseif(LLVM_MESON_DYLIB)
      # Dynamic was requested, and we request optional modules only. Continue
      continue()
    else()
      # CMake only do this for static components, and we
      # replicate its behaviour
      # Get the mapped components
      llvm_map_components_to_libnames(out_mods ${mod} ${mod_L} ${mod_U})
      list(SORT              out_mods)
      list(REMOVE_DUPLICATES out_mods)

      # Make sure that the modules exist
      foreach(i IN LISTS out_mods)
        set(static_tg FALSE)
        is_static(${i} static_tg)
        if(static_tg)
          list(APPEND real_mods ${i})
        endif()
      endforeach()

      # Set the output variables
      set(MESON_LLVM_TARGETS_${mod} ${real_mods})
      foreach(i IN LISTS real_mods)
        set(MESON_TARGET_TO_LLVM_${i} ${mod})
      endforeach()
    endif()
  endforeach()

  # Check the following variables:
  # LLVM_PACKAGE_VERSION
  # LLVM_VERSION
  # LLVM_VERSION_STRING
  if(NOT DEFINED PACKAGE_VERSION)
    if(DEFINED LLVM_PACKAGE_VERSION)
      set(PACKAGE_VERSION "${LLVM_PACKAGE_VERSION}")
    elseif(DEFINED LLVM_VERSION)
      set(PACKAGE_VERSION "${LLVM_VERSION}")
    elseif(DEFINED LLVM_VERSION_STRING)
      set(PACKAGE_VERSION "${LLVM_VERSION_STRING}")
    endif()
  endif()

  # Check the following variables:
  # LLVM_LIBRARIES
  # LLVM_LIBS
  set(libs)
  #Hardcode LLVM, because we links with libLLVM.so when dynamic
  if(LLVM_MESON_DYLIB)
    get_target_property(libs LLVM IMPORTED_LOCATION)
  elseif(DEFINED LLVM_LIBRARIES)
    set(libs LLVM_LIBRARIES)
  elseif(DEFINED LLVM_LIBS)
    set(libs LLVM_LIBS)
  endif()

  # Check the following variables:
  # LLVM_INCLUDE_DIRS
  # LLVM_INCLUDES
  # LLVM_INCLUDE_DIR
  set(includes)
  if(DEFINED LLVM_INCLUDE_DIRS)
    set(includes LLVM_INCLUDE_DIRS)
  elseif(DEFINED LLVM_INCLUDES)
    set(includes LLVM_INCLUDES)
  elseif(DEFINED LLVM_INCLUDE_DIR)
    set(includes LLVM_INCLUDE_DIR)
  endif()

  # Check the following variables:
  # LLVM_DEFINITIONS
  set(definitions)
  if(DEFINED LLVM_DEFINITIONS)
    set(definitions LLVM_DEFINITIONS)
  endif()

  set(PACKAGE_INCLUDE_DIRS "${${includes}}")
  set(PACKAGE_DEFINITIONS  "${${definitions}}")
  set(PACKAGE_LIBRARIES    "${${libs}}")
endif()