cmake_minimum_required(VERSION 3.8...3.19)

# Read version from version.hpp
file(READ "${CMAKE_CURRENT_LIST_DIR}/include/tao/pegtl/version.hpp" version_hpp_data)
string(REGEX MATCH "#define TAO_PEGTL_VERSION \"([^\"]+)\"" _ ${version_hpp_data})
set(PEGTL_VERSION "${CMAKE_MATCH_1}")

project(pegtl VERSION ${PEGTL_VERSION} LANGUAGES CXX)

set(PEGTL_IS_MAIN_PROJECT OFF)
if(CMAKE_CURRENT_SOURCE_DIR STREQUAL CMAKE_SOURCE_DIR)
  set(PEGTL_IS_MAIN_PROJECT ON)
endif()

if(PEGTL_HAS_PARENT)
  # Multiple versions of PEGTL can't co-exist
  if(NOT ${PROJECT_NAME}_VERSION STREQUAL ${PROJECT_VERSION})
    message(FATAL_ERROR "Multiple mismatched PEGTL versions")
  endif()

  # Only include if this is the first include
  if(NOT ${PROJECT_NAME}_DIR STREQUAL "${PROJECT_BINARY_DIR}")
    return()
  endif()
endif()

# Keep track of pegtl version
set(${PROJECT_NAME}_FOUND TRUE CACHE BOOL "" FORCE)
set(${PROJECT_NAME}_VERSION "${PROJECT_VERSION}" CACHE STRING "" FORCE)
set(${PROJECT_NAME}_DIR "${PROJECT_BINARY_DIR}" CACHE PATH "" FORCE)

mark_as_advanced(${PROJECT_NAME}_FOUND)
mark_as_advanced(${PROJECT_NAME}_VERSION)
mark_as_advanced(${PROJECT_NAME}_DIR)

# installation directories
set(PEGTL_INSTALL_INCLUDE_DIR "include" CACHE STRING "The installation include directory")
set(PEGTL_INSTALL_DOC_DIR "share/doc/tao/pegtl" CACHE STRING "The installation doc directory")
set(PEGTL_INSTALL_CMAKE_DIR "share/pegtl/cmake" CACHE STRING "The installation cmake directory")

# define a header-only library
add_library(pegtl INTERFACE)
add_library(taocpp::pegtl ALIAS pegtl)
target_include_directories(pegtl INTERFACE
  $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/include>
  $<INSTALL_INTERFACE:${PEGTL_INSTALL_INCLUDE_DIR}>
)

target_link_libraries(pegtl INTERFACE filesystem)

# require C++17
target_compile_features(pegtl INTERFACE cxx_std_17)

option(PEGTL_USE_BOOST_FILESYSTEM "Override the auto-detection of std::filesystem and use Boost.Filesystem" OFF)

# Try compiling a test program with std::filesystem or one of its alternatives
function(check_filesystem_impl FILESYSTEM_HEADER FILESYSTEM_NAMESPACE OPTIONAL_LIBS OUT_RESULT)
  set(TEST_FILE "test_${OUT_RESULT}.cpp")
  configure_file(.cmake/test_filesystem.cpp.in ${TEST_FILE} @ONLY)

  try_compile(TEST_RESULT
    ${CMAKE_CURRENT_BINARY_DIR}
    ${CMAKE_CURRENT_BINARY_DIR}/${TEST_FILE}
    CXX_STANDARD 17)

  if(NOT TEST_RESULT)
    # Retry with each of the optional libraries
    foreach(OPTIONAL_LIB IN LISTS OPTIONAL_LIBS)
      try_compile(TEST_RESULT
        ${CMAKE_CURRENT_BINARY_DIR}
        ${CMAKE_CURRENT_BINARY_DIR}/${TEST_FILE}
        LINK_LIBRARIES ${OPTIONAL_LIB}
        CXX_STANDARD 17)

      if(TEST_RESULT)
        # Looks like the optional library was required, go ahead and add it to the link options.
        message(STATUS "Adding ${OPTIONAL_LIB} to the PEGTL to build with ${FILESYSTEM_NAMESPACE}.")
        target_link_libraries(${PROJECT_NAME} INTERFACE ${OPTIONAL_LIB})
        break()
      endif()
    endforeach()
  endif()

  set(${OUT_RESULT} ${TEST_RESULT} PARENT_SCOPE)
endfunction()

# testing
option(PEGTL_BUILD_TESTS "Build test programs" ${PEGTL_IS_MAIN_PROJECT})
if(PEGTL_BUILD_TESTS)
  enable_testing()
  add_subdirectory(src/test/pegtl)
endif()

# examples
option(PEGTL_BUILD_EXAMPLES "Build example programs" ${PEGTL_IS_MAIN_PROJECT})
if(PEGTL_BUILD_EXAMPLES)
  add_subdirectory(src/example/pegtl)
endif()

# Make package findable
configure_file(.cmake/pegtl-config.cmake.in pegtl-config.cmake @ONLY)

# Ignore pointer width differences since this is a header-only library
unset(CMAKE_SIZEOF_VOID_P)

# Enable version checks in find_package
include(CMakePackageConfigHelpers)
write_basic_package_version_file(pegtl-config-version.cmake COMPATIBILITY SameMajorVersion)

# install and export target