set (ASCIIDOC_MANS
  man1/wsjtx.1.txt
  )

find_program (A2X_EXECUTABLE NAMES a2x a2x.py)
if (NOT A2X_EXECUTABLE)
  if (NOT CMAKE_BUILD_TYPE STREQUAL "Debug")
    message (SEND_ERROR "Failed to find a2x which is an optional requirement for non-debug
builds on *nix platforms.

You can choose to skip manpage generation and this error by setting
the CMake option WSJT_SKIP_MANPAGES to ON. This option is designed for
those that are building for their own use, package builders should not
opt to skip manpage generation since package building requires the
manpages.")

  else (NOT CMAKE_BUILD_TYPE STREQUAL "Debug")
    message (WARNING "Failed to find a2x skipping manpage generation.")
  endif (NOT CMAKE_BUILD_TYPE STREQUAL "Debug")
endif ()
find_program (GZIP_EXECUTABLE NAMES gzip)
find_program (SED_EXECUTABLE NAMES sed)

set (XSLTPROC_OPTS 
  "-param man.endnotes.list.enabled 0 -param man.endnotes.are.numbered 0"
  )
set (A2X_OPTS
  --format=manpage
  --xsltproc-opts=${XSLTPROC_OPTS}
  --doctype=manpage
  --no-xmllint
  )

set (MANPAGES)
if (A2X_EXECUTABLE AND GZIP_EXECUTABLE AND SED_EXECUTABLE)
  file (MAKE_DIRECTORY man)
  foreach (f IN LISTS ASCIIDOC_MANS)
    get_filename_component (d "${f}" PATH)
    string (SUBSTRING "${d}" 3 -1 section)
    if (NOT section MATCHES "[1-9]")
      message (SEND_ERROR "Invalid man section ${section} in ${f}")
    endif (NOT section MATCHES "[1-9]")
    get_filename_component (filename "${f}" NAME_WE)
    set (f "${CMAKE_CURRENT_SOURCE_DIR}/${f}")
    set (d "man/${d}")
    set (o "${d}/${filename}.${section}")
    add_custom_command (OUTPUT "${o}.gz"
      COMMAND ${CMAKE_COMMAND} ARGS -E make_directory "${d}"
      COMMAND ${A2X_EXECUTABLE} ARGS ${A2X_OPTS} -D "${d}" "${f}"
      COMMAND ${GZIP_EXECUTABLE} ARGS -f9 "${o}"
      COMMAND ${SED_EXECUTABLE} ARGS -e "'s@.so @&man${section}/@'" -i.orig "${d}/*.${section}"
      COMMAND ${GZIP_EXECUTABLE} ARGS -f9 "${d}/*.${section}"
      DEPENDS "${f}"
      COMMENT "Generating ${o}.gz"
      )
    list (APPEND MANPAGES "${o}.gz")
  endforeach ()

  install (
    DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}/man
    DESTINATION ${WSJT_MANPAGE_DESTINATION}
    PATTERN "*.orig" EXCLUDE
    #COMPONENT Runtime
    )
endif (A2X_EXECUTABLE AND GZIP_EXECUTABLE AND SED_EXECUTABLE)

add_custom_target (manpages DEPENDS ${MANPAGES})