# Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
# file Copyright.txt or https://cmake.org/licensing for details.

#.rst:
# FindGit
# -------
#
# The module defines the following variables:
#
# ``GIT_EXECUTABLE``
#   Path to Git command-line client.
# ``Git_FOUND``, ``GIT_FOUND``
#   True if the Git command-line client was found.
# ``GIT_VERSION_STRING``
#   The version of Git found.
#
# Example usage:
#
# .. code-block:: cmake
#
#    find_package(Git)
#    if(Git_FOUND)
#      message("Git found: ${GIT_EXECUTABLE}")
#    endif()

# Look for 'git' or 'eg' (easy git)
#
set(git_names git eg)

# Prefer .cmd variants on Windows unless running in a Makefile
# in the MSYS shell.
#
if(CMAKE_HOST_WIN32)
  if(NOT CMAKE_GENERATOR MATCHES "MSYS")
    set(git_names git.cmd git eg.cmd eg)
    # GitHub search path for Windows
    file(GLOB github_path
      "$ENV{LOCALAPPDATA}/Github/PortableGit*/cmd"
      "$ENV{LOCALAPPDATA}/Github/PortableGit*/bin"
      )
    # SourceTree search path for Windows
    set(_git_sourcetree_path "$ENV{LOCALAPPDATA}/Atlassian/SourceTree/git_local/bin")
  endif()
endif()

# First search the PATH and specific locations.
find_program(GIT_EXECUTABLE
  NAMES ${git_names}
  PATHS ${github_path} ${_git_sourcetree_path}
  DOC "Git command line client"
  )

if(CMAKE_HOST_WIN32)
  # Now look for installations in Git/ directories under typical installation
  # prefixes on Windows.  Exclude PATH from this search because VS 2017's
  # command prompt happens to have a PATH entry with a Git/ subdirectory
  # containing a minimal git not meant for general use.
  find_program(GIT_EXECUTABLE
    NAMES ${git_names}
    PATH_SUFFIXES Git/cmd Git/bin
    NO_SYSTEM_ENVIRONMENT_PATH
    DOC "Git command line client"
    )
endif()

mark_as_advanced(GIT_EXECUTABLE)

MACRO(Git_WC_INFO dir prefix)
    EXECUTE_PROCESS(COMMAND ${Git_EXECUTABLE} log -r --pretty=format:"%d;%H;%an" .
      WORKING_DIRECTORY ${dir}
      OUTPUT_VARIABLE ${prefix}_WC_INFO
      ERROR_VARIABLE Git_info_error
      RESULT_VARIABLE Git_info_result
      OUTPUT_STRIP_TRAILING_WHITESPACE)

    IF(NOT ${Git_info_result} EQUAL 0)
      MESSAGE(SEND_ERROR "Command \"${GIT_EXECUTABLE} log\" failed with output:\n${Git_info_error}")
    ELSE()
      LIST(LENGTH ${prefix}_WC_INFO _COUNT)
      IF(_COUNT EQUAL 4)
        LIST(GET ${prefix}_WC_INFO 0 ${prefix}_WC_REVISION)
        LIST(GET ${prefix}_WC_INFO 1 ${prefix}_WC_CHANGESET)
        LIST(GET ${prefix}_WC_INFO 3 ${prefix}_WC_LAST_CHANGED_AUTHOR)
      ELSE()
        MESSAGE(STATUS "Bad output from HG")
        SET(${prefix}_WC_REVISION "unknown")
        SET(${prefix}_WC_CHANGESET "unknown")
        SET(${prefix}_WC_BRANCH "unknown")
      ENDIF()
    ENDIF()

  ENDMACRO()

unset(git_names)
unset(_git_sourcetree_path)

if(GIT_EXECUTABLE)
  execute_process(COMMAND ${GIT_EXECUTABLE} --version
                  OUTPUT_VARIABLE git_version
                  ERROR_QUIET
                  OUTPUT_STRIP_TRAILING_WHITESPACE)
  if (git_version MATCHES "^git version [0-9]")
    string(REPLACE "git version " "" GIT_VERSION_STRING "${git_version}")
  endif()
  unset(git_version)
endif()