find_package(Git REQUIRED)

if (DEFINED ENV{GITHUB_BRANCH_NAME})
  set(GIT_BUILD_BRANCH $ENV{GITHUB_BRANCH_NAME})
  set(GIT_COMMIT_HASH $ENV{GITHUB_HEAD_SHA})
else ()
  set(GIT_COMMAND branch --show-current)
  execute_process(
    COMMAND ${GIT_EXECUTABLE} ${GIT_COMMAND} WORKING_DIRECTORY ${CMAKE_SOURCE_DIR} OUTPUT_VARIABLE GIT_BUILD_BRANCH
    OUTPUT_STRIP_TRAILING_WHITESPACE COMMAND_ERROR_IS_FATAL ANY
  )

  set(GIT_COMMAND rev-parse HEAD)
  execute_process(
    COMMAND ${GIT_EXECUTABLE} ${GIT_COMMAND} WORKING_DIRECTORY ${CMAKE_SOURCE_DIR} OUTPUT_VARIABLE GIT_COMMIT_HASH
    OUTPUT_STRIP_TRAILING_WHITESPACE COMMAND_ERROR_IS_FATAL ANY
  )
endif ()

execute_process(
  COMMAND date +%Y%m%d%H%M%S WORKING_DIRECTORY ${CMAKE_SOURCE_DIR} OUTPUT_VARIABLE BUILD_DATE
  OUTPUT_STRIP_TRAILING_WHITESPACE COMMAND_ERROR_IS_FATAL ANY
)

message(STATUS "Git branch: ${GIT_BUILD_BRANCH}")
message(STATUS "Git commit hash: ${GIT_COMMIT_HASH}")
message(STATUS "Build date: ${BUILD_DATE}")

if (DEFINED ENV{FORCE_CLIO_VERSION} AND NOT "$ENV{FORCE_CLIO_VERSION}" STREQUAL "")
  message(STATUS "Using explicitly provided '${FORCE_CLIO_VERSION}' as Clio version")

  set(CLIO_VERSION "$ENV{FORCE_CLIO_VERSION}")
  set(DOC_CLIO_VERSION "$ENV{FORCE_CLIO_VERSION}")
else ()
  message(STATUS "Using 'YYYYMMDDHMS-<branch>-<git short rev>' as Clio version")

  string(SUBSTRING ${GIT_COMMIT_HASH} 0 7 GIT_COMMIT_HASH_SHORT)

  set(CLIO_VERSION "${BUILD_DATE}-${GIT_BUILD_BRANCH}-${GIT_COMMIT_HASH_SHORT}")
  set(DOC_CLIO_VERSION "develop")
endif ()

if (CMAKE_BUILD_TYPE MATCHES Debug)
  set(CLIO_VERSION "${CLIO_VERSION}+DEBUG")
endif ()

message(STATUS "Build version: ${CLIO_VERSION}")