cmake_minimum_required(VERSION 3.0)

# define the project
project(nlohmann_json VERSION 2.1.0 LANGUAGES CXX)

enable_testing()

option(BuildTests "Build the unit tests" ON)

# define project variables
set(JSON_TARGET_NAME ${PROJECT_NAME})
set(JSON_PACKAGE_NAME ${JSON_TARGET_NAME})
set(JSON_TARGETS_FILENAME "${JSON_PACKAGE_NAME}Targets.cmake")
set(JSON_CONFIG_FILENAME "${JSON_PACKAGE_NAME}Config.cmake")
set(JSON_CONFIGVERSION_FILENAME "${JSON_PACKAGE_NAME}ConfigVersion.cmake")
set(JSON_CONFIG_DESTINATION "cmake")
set(JSON_INCLUDE_DESTINATION "include/nlohmann")

set(CMAKE_MODULE_PATH "${CMAKE_SOURCE_DIR}/cmake")

# create and configure the library target
add_library(${JSON_TARGET_NAME} INTERFACE)
target_include_directories(${JSON_TARGET_NAME} INTERFACE
  $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/src>
  $<INSTALL_INTERFACE:${JSON_INCLUDE_DESTINATION}>)

# create and configure the unit test target
if(BuildTests)
    add_subdirectory(test)
endif()

# generate a config and config version file for the package
include(CMakePackageConfigHelpers)
configure_package_config_file("cmake/config.cmake.in"
    "${CMAKE_CURRENT_BINARY_DIR}/${JSON_CONFIG_FILENAME}"
    INSTALL_DESTINATION ${JSON_CONFIG_DESTINATION}
    PATH_VARS JSON_INCLUDE_DESTINATION)
write_basic_package_version_file("${CMAKE_CURRENT_BINARY_DIR}/${JSON_CONFIGVERSION_FILENAME}"
    VERSION ${PROJECT_VERSION}
    COMPATIBILITY SameMajorVersion)

# export the library target and store build directory in package registry
export(TARGETS ${JSON_TARGET_NAME}
    FILE "${CMAKE_CURRENT_BINARY_DIR}/${JSON_TARGETS_FILENAME}")
export(PACKAGE ${JSON_PACKAGE_NAME})

# install library target and config files
install(TARGETS ${JSON_TARGET_NAME}
    EXPORT ${JSON_PACKAGE_NAME})
install(FILES "src/json.hpp"
    DESTINATION ${JSON_INCLUDE_DESTINATION})
install(EXPORT ${JSON_PACKAGE_NAME}
    FILE ${JSON_TARGETS_FILENAME}
    DESTINATION ${JSON_CONFIG_DESTINATION})
install(FILES "${CMAKE_CURRENT_BINARY_DIR}/${JSON_CONFIG_FILENAME}"
    "${CMAKE_CURRENT_BINARY_DIR}/${JSON_CONFIGVERSION_FILENAME}"
    DESTINATION ${JSON_CONFIG_DESTINATION})