IF(CMAKE_BINARY_DIR)
  MESSAGE(FATAL_ERROR "CPackDeb.cmake may only be used by CPack internally.")
ENDIF(CMAKE_BINARY_DIR)

IF(NOT UNIX)
  MESSAGE(FATAL_ERROR "CPackDeb.cmake may only be used under UNIX.")
ENDIF(NOT UNIX)

FIND_PROGRAM(AR_EXECUTABLE ar)

IF(NOT AR_EXECUTABLE)
  # Is there a *NIX out there without ar ?
  MESSAGE(FATAL_ERROR "Debian package requires ar executable")
ENDIF(NOT AR_EXECUTABLE)

# Let's define the control file found in debian package:

# Package:
# debian policy enforce lower case for package name
IF(NOT DEBIAN_PACKAGE_NAME)
  STRING(TOLOWER "${CPACK_PACKAGE_NAME}" DEBIAN_PACKAGE_NAME)
ENDIF(NOT DEBIAN_PACKAGE_NAME)

# Version:
IF(NOT DEBIAN_PACKAGE_VERSION)
  IF(NOT CPACK_PACKAGE_VERSION)
    MESSAGE(FATAL_ERROR "Debian package requires a package version")
  ENDIF(NOT CPACK_PACKAGE_VERSION)
  SET(DEBIAN_PACKAGE_VERSION ${CPACK_PACKAGE_VERSION})
ENDIF(NOT DEBIAN_PACKAGE_VERSION)

# Architecture:
IF(NOT DEBIAN_PACKAGE_ARCHITECTURE)
# There is no such thing as i686 architecture on debian, you should use i386 instead
# $ dpkg --print-architecture
  SET(DEBIAN_PACKAGE_ARCHITECTURE i386)
ENDIF(NOT DEBIAN_PACAKGE_ARCHITECTURE)

# Depends:
IF(NOT DEBIAN_PACKAGE_DEPENDS)
  SET(DEBIAN_PACKAGE_DEPENDS
    "libc6 (>= 2.3.1-6), libgcc1 (>= 1:3.4.2-12)"
  )
ENDIF(NOT DEBIAN_PACKAGE_DEPENDS)

# Maintainer:
IF(NOT DEBIAN_PACKAGE_MAINTAINER)
  IF(NOT CPACK_PACKAGE_CONTACT)
    MESSAGE(FATAL_ERROR "Debian package requires a maintainer for a package, set CPACK_PACKAGE_CONTACT or DEBIAN_PACKAGE_MAINTAINER")
  ENDIF(NOT CPACK_PACKAGE_CONTACT)
  SET(DEBIAN_PACKAGE_MAINTAINER ${CPACK_PACKAGE_CONTACT})
ENDIF(NOT DEBIAN_PACKAGE_MAINTAINER)

# Description:
IF(NOT DEBIAN_PACKAGE_DESCRIPTION)
  IF(NOT CPACK_PACKAGE_DESCRIPTION_SUMMARY)
    MESSAGE(FATAL_ERROR "Debian package requires a summary for a package, set CPACK_PACKAGE_DESCRIPTION_SUMMARY or DEBIAN_PACKAGE_DESCRIPTION")
  ENDIF(NOT CPACK_PACKAGE_DESCRIPTION_SUMMARY)
  SET(DEBIAN_PACKAGE_DESCRIPTION ${CPACK_PACKAGE_DESCRIPTION_SUMMARY})
ENDIF(NOT DEBIAN_PACKAGE_DESCRIPTION)