#
# Copyright(c) 2006 to 2018 ADLINK Technology Limited and others
#
# This program and the accompanying materials are made available under the
# terms of the Eclipse Public License v. 2.0 which is available at
# http://www.eclipse.org/legal/epl-2.0, or the Eclipse Distribution License
# v. 1.0 which is available at
# http://www.eclipse.org/org/documents/edl-v10.php.
#
# SPDX-License-Identifier: EPL-2.0 OR BSD-3-Clause
#
if(DEFINED ENV{M2})
  list(APPEND _mvn_hints "$ENV{M2}")
endif()

if(DEFINED ENV{M2_HOME})
  list(APPEND _mvn_hints "$ENV{M2_HOME}/bin")
endif()

# Chocolatey installs packages under C:\ProgramData\chocolatey.
if(NOT "$ENV{ProgramData}" STREQUAL "")
  if(IS_DIRECTORY "$ENV{ProgramData}/chocolatey/bin")
    list(APPEND _mvn_paths "$ENV{ProgramData}/chocolatey/bin")
  endif()
  if(IS_DIRECTORY "$ENV{ProgramData}/chocolatey/bin")
    list(APPEND _dirs "$ENV{ProgramData}/chocolatey/lib/maven")
  endif()
endif()

# Maven documentation mentions intalling maven under C:\Program Files on
# Windows and under /opt on *NIX platforms.
if(WIN32)
  foreach(_env "ProgramFiles" "ProgramFiles(x86)")
    if(ENV{${_env}} AND IS_DIRECTORY "$ENV{${_env}}")
      list(APPEND _dirs "$ENV{${_env}}")
    endif()
  endforeach()
else()
  list(APPEND _dirs "/opt")
endif()

foreach(_dir ${_dirs})
  file(GLOB _mvn_dirs "${_dir}/apache-maven-*")
  foreach(_mvn_dir ${_mvn_dirs})
    if((IS_DIRECTORY "${_mvn_dir}") AND (IS_DIRECTORY "${_mvn_dir}/bin"))
      list(APPEND _mvn_paths "${_mvn_dir}/bin")
    endif()
  endforeach()
endforeach()

if(WIN32)
  set(_mvn_names "mvn.cmd" "mvn.exe")
else()
  set(_mvn_names "mvn")
endif()

find_program(Maven_EXECUTABLE
  NAMES ${_mvn_names}
  HINTS ${_mvn_hints}
  PATHS ${_mvn_paths})

if(Maven_EXECUTABLE)
  execute_process(COMMAND ${Maven_EXECUTABLE} -version
    RESULT_VARIABLE res
    OUTPUT_VARIABLE var
    ERROR_VARIABLE var
    OUTPUT_STRIP_TRAILING_WHITESPACE
    ERROR_STRIP_TRAILING_WHITESPACE)
  if(NOT res)
    if(var MATCHES "Apache Maven ([0-9]+)\\.([0-9]+)\\.([0-9]+)")
      set(Maven_VERSION "${CMAKE_MATCH_1}.${CMAKE_MATCH_2}.${CMAKE_MATCH_3}")
    endif()
  endif()
endif()

include(FindPackageHandleStandardArgs)
find_package_handle_standard_args(Maven
  FOUND_VAR Maven_FOUND
  VERSION_VAR Maven_VERSION
  REQUIRED_VARS Maven_EXECUTABLE Maven_VERSION)

mark_as_advanced(Maven_FOUND Maven_EXECUTABLE Maven_VERSION)