#!/bin/bash
#emacs: -*- mode: shell-script; c-basic-offset: 4; tab-width: 4; indent-tabs-mode: nil -*-
#ex: set sts=4 ts=4 sw=4 et:

# play safe
set -e
set -u

############
# Defaults #
############

nd_aptenable_version=0.1

nd_key_id=0x2649A5A9

# To be set by cmdline args
ae_release=
ae_components=software,data
ae_flavor=
ae_mirror_main=http://neuro.debian.net/debian
ae_mirror=
ae_suffix=
ae_verbose=1
ae_overwrite=
ae_sources=
ae_dry_run=

ae_sudo=

# TODOs:
# - distribute/enable key
# - apt priority! (so we could avoid automagic upgrades etc)
# - multiarch setups


# TODO -- consider fetching the most recent version from online
# concerns -- without any validation might be subject to injection through man-in-the-middle etc
nd_configfile=/etc/neurodebian/neurodebian.cfg # TODO - comes from neurodebian-devel pkg...
# TODO: Or should it be parsed out from the NeuroDebian website itself?
#  may be we could provide that file from the neurodebian website...

print_verbose()
{
    level=$1; shift
	if [ "$ae_verbose" -ge $level ]; then
        echo -e "I: $*"
    fi
}

error()
{
    code=$1; shift
	echo -e "E: $*" >&2
    exit $code
}

print_version()
{
cat << EOT
nd-aptenable $nd_aptenable_version

Copyright (C) 2014 Yaroslav Halchenko <debian@onerussian.com>

Licensed under GNU Public License version 3 or later.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

Written by Yaroslav Halchenko for the NeuroDebian project.

EOT
}

eval_dry()
{
    if [ -z "$ae_dry_run" ]; then
        eval "$ae_sudo $@"
    else
        echo "DRY: $@"
    fi
}

print_help()
{
cat << EOT

Usage:  nd-aptenable [options]

Enables NeuroDebian repository for the current Debian or Ubuntu release.

Options:

  -r, --release=RELEASE
    Name of the Debian/Ubuntu release to be used.  If not specified,
    it is deduced from the  apt-cache policy  output, by taking repository
    of Debian or Ubuntu origin with highest priority.

  -f, --flavor=full|libre
    Which flavor of the repository should be enabled:
     libre -- Only  main  component, containing only DFSG-compliant content.
     full -- Includes main, contrib, and non-free.
    If not specified -- deduced from the output of apt-cache policy

  -c, --components=c1,c2,c3
    Comma separated list of components to enable among:
     software -- primary software repository
     data -- data packages
     devel -- "overlay" of development versions (like Debian "experimental").
              Not sufficient on its own and available only from the main site
    If not specified -- "software,data"

  -m, --mirror=NAME|URL
    Which mirror to use.  Could be a mirror code-name (as specified in
    /etc/neurodebian/neurodebian.cfg), or a URL (TODO).

  --overwrite,
    If apt file already present, it would not be overriden (by default).
    Use this option to overwrite.

  --suffix=SUFFIX
    Which suffix to add to the apt file, in case you are trying to enable
    multiple repositories

  --sources, --no-sources
    Either to enable deb-src lines.  If not specified -- deduced based on ??? TODO

  -n, --dry-run
    Do not perform any changes -- generated configurations and commands will
    simply be printed to stdout

  -v, --verbose
    Enable additional progress messages.  Could be used multiple times

  -q, --quiet
    Make operation quiet -- only error messages would be output

  -h, --help
    Print short description, usage summary and option list.

  --version
    Print version information and exit.

Exit status:

  non-0 exit status in case of error.  Error exit code would depend
  on which command has failed

Examples:

  - Enable software and data components from the optimal (according to
    netselect) mirror.  Some information about progress will be printed

    nd-aptenable

  - Quietly enable -devel repository for the current release, and place apt
    configuration into /etc/apt/sources.list.d/neurodebian.sources-devel.list

    nd-aptenable -q --suffix=-devel -c devel

  - Force sid distribution, all the components, from the Japan mirror:

    nd-aptenable -q --suffix=-de-sid-full -c software,data,devel -m jp

EOT
}

get_mirrors() {
    # Determine available mirrors by fetching our .cfg file
    /etc/neurodebian/neurodebian.cfg
}

print_mirrors() {
    echo "TODO"
    exit 1
}

get_apt_policy() {
    # Get apt-cache policy output in a single list for matching suites
    # (could be a separated with \| or , for multiple choices, e.g.
    #
    # get_apt_policy Debian,Ubuntu
    # or
    # get_apt_policy NeuroDebian
    suites="$1"
    apt-cache policy | grep -B1 -e "o=\(${suites//,/\\|}\)" | tr '\n' ' ' | sed -e 's, -- ,\n,g' | grep -v -e '-\(updates\|security\)' | sort -nr
}

include_component() {
    echo "$ae_components" | tr ',' '\n' | grep -q "^$1\$"
}


#
# Commandline options handling
#

# Parse commandline options (taken from the getopt examples from the Debian util-linux package)
# Note that we use `"$@"' to let each command-line parameter expand to a
# separate word. The quotes around `$@' are essential!
# We need CLOPTS as the `eval set --' would nuke the return value of getopt.
CLOPTS=`getopt -o h,r:,m:,f:,c:,q,v,n --long help,version,quiet,verbose,mirror:,release:,flavor:,components:,suffix:,overwrite,sources,no-sources,dry-run,print-mirrors -n 'nd-aptenable' -- "$@"`

if [ $? != 0 ] ; then
  error 2 "Problem with parsing cmdline.  Terminating..."
fi

# Note the quotes around `$CLOPTS': they are essential!
eval set -- "$CLOPTS"

while true ; do
  case "$1" in
	  -r|--release) shift; ae_release="$1"; shift;;
	  -f|--flavor) shift;  ae_flavor="$1"; shift;;
	  -c|--components) shift; ae_components="$1"; shift;;
      # TODO
      -m|--mirror) shift;  ae_mirror="$1"; shift;;
      # TODO
         --print-mirrors)  print_mirrors; exit 0;;
      -n|--dry-run)        ae_dry_run=1; shift;;
         --suffix) shift;  ae_suffix="$1"; shift;;
         --overwrite)      ae_overwrite="$1"; shift;;
         --sources)        ae_sources=1; shift;;
         --no-sources)     ae_sources=0; shift;;
	  -q|--quiet)          ae_verbose=0; shift;;
	  -v|--verbose)        ae_verbose=$(($ae_verbose+1)); shift;;
	  -h|--help) print_help; exit 0;;
	  --version) print_version; exit 0;;
	  --) shift ; break ;;
	  *) error 1 "Internal error! ($1)";;
  esac
done


if [ $# -gt 0 ] ; then
    print_help >&2
    exit 2
fi


#
# Basic system/environment knowledge
#

ae_output_file=/etc/apt/sources.list.d/neurodebian.sources${ae_suffix}.list

if [ `whoami` != "root" ]; then
    print_verbose 1 "This script requires root access.  Since current user is not root, sudo will be used"
    ae_sudo=sudo
fi

apt_policy=$(get_apt_policy "Debian,Ubuntu" )

if [ -z "$ae_release" ]; then
    ae_release=$(echo "$apt_policy" | head -1 | sed -e 's/.*,n=\([^,]*\),.*/\1/g')
fi

if [ -z "$ae_flavor" ]; then
    ae_flavor=$(echo "$apt_policy" | grep -e ",n=$ae_release," | grep -qe 'c=\(non-free\|restricted\)' && echo "full" || echo "libre")
fi

#
# Determine which mirror to use
#

# TODO -- determine mirror URL
# Not necessary for -devel available only from the main site
if include_component software || include_component data; then
    # for now just use default
    if [ -z "$ae_mirror" ]; then # none specified
        ae_mirror_url=$ae_mirror_main
    else
        if [ ! "$ae_mirror" ~= ".*://.*" ]; then
            # TODO -- determine from the abbreviation
        fi
    fi
fi


#
# Prepare APT file
#

case $ae_flavor in
 full)  apt_flavor="contrib non-free";;
 libre) apt_flavor="";;
 *) error 5 "Unknown value of flavor $apt_flavor.  Must be full or libre"
esac

if [ -z "$ae_sources" ] || [ $ae_sources -eq 0 ]; then
    sources_comment="#"
else
    sources_comment=""
fi

apt_list=

if include_component software; then
    apt_list+="
# NeuroDebian software repository
deb     $ae_mirror_url $ae_release main $apt_flavor
${sources_comment}deb-src $ae_mirror_url $ae_release main $apt_flavor
"
fi

if include_component data; then
    apt_list+="
# NeuroDebian data repository
deb     $ae_mirror_url data main $apt_flavor
${sources_comment}deb-src $ae_mirror_url data main $apt_flavor
"
fi

if include_component devel; then
    apt_list+="
# NeuroDebian -devel repository
deb     http://neuro.debian.net/debian-devel $ae_release main $apt_flavor
${sources_comment}deb-src http://neuro.debian.net/debian-devel $ae_release main $apt_flavor
"
fi

if [ -e "$ae_output_file" ] && [ -z "$ae_overwrite" ]; then
    # error 3
    print_verbose 1 "File $ae_output_file already exists, containing:\n\n`cat \"$ae_output_file\"`\n\nI: Use --overwrite option to regenerate with:\n\n$apt_list"
else
    print_verbose 1 "Generating $ae_output_file"
    if [ -z "$ae_dry_run" ]; then
        echo "$apt_list" >| "$ae_output_file"
    else
        echo "DRY:"
        echo "$apt_list"
    fi
fi


#
# Assure present archive GPG key for APT system
#

# Figure out if key needs to be imported (if ran within package,
# should already be there due to neurodebian-keyring package)
if LANG=C eval $ae_sudo apt-key export $nd_key_id 2>&1 1>/dev/null | grep -qe "nothing exported"; then
    print_verbose 1 "Fetching the key from the server"
    eval_dry apt-key adv --recv-keys --keyserver pgp.mit.edu $nd_key_id
fi

#
# Finalizing (apt-get update etc)
#

print_verbose 1 "Updating APT listings, might take a few minutes"
if [ -z "$ae_dry_run" ]; then
    apt_logfile=$(mktemp)
    $ae_sudo apt-get update 1>"$apt_logfile" 2>&1 \
        && rm -f "$apt_logfile" \
        || {
             cat "$apt_logfile"
             error 5 "E: Update failed with exit code $? (above output logged into $apt_logfile)."
             }
else
    eval_dry apt-get update
fi

if [ "$ae_verbose" -ge 2 ]; then
    print_verbose 2 "Currently enabled NeuroDebian suites/mirrors:"
    get_apt_policy NeuroDebian
fi