#!/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:

# Depends:    apt, python, wget
# Recommends: netselect

# play safe
set -e
set -u

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

nd_aptenable_version=0.1

nd_key_id=0x2649A5A9
nd_config_file=/etc/neurodebian/neurodebian.cfg
nd_mirror_origin=http://neuro.debian.net/debian
nd_mirror_default=$nd_mirror_origin # or may be AWS?

# To be set by cmdline args
ae_release=
ae_components=software,data
ae_flavor=
ae_mirror=best
ae_suffix=
ae_verbose=1
ae_overwrite=
ae_sources=
ae_dry_run=

ae_sudo=
exe_dir=$(dirname $0)

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

ae_tempdir=$(mktemp -d)
trap "rm -rf \"$ae_tempdir\"" TERM INT EXIT


print_verbose()
{
    level=$1; shift
	if [ "$ae_verbose" -ge $level ]; then
        # use stderr for printing within functions stdout of which might be used
        echo -e "I: $*" >&2
    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 Debians' "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.

  --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 none specified -- would be enabled if
    sources for a core package (apt) are available.

  -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_neurodebian_cfg()
{
    # First we try to fetch the most recent version from the github
    print_verbose 3 "Fetching config file from the github repository"
    cfgfile_temp="$ae_tempdir/neurodebian.cfg"
    wget -c -q -O$cfgfile_temp https://raw.githubusercontent.com/neurodebian/neurodebian/master/neurodebian.cfg \
        && { echo $cfgfile_temp; } \
        || { [ -e "$nd_config_file" ] && return "$nd_config_file"; }
    # if not -- should blow up
}

query_cfg_section()
{
    config_file="$1"
    section="$2"
    python -c "from ConfigParser import SafeConfigParser as SP; cfg = SP(); cfg.read('$config_file'); print('\n'.join([' '.join(x) for x in cfg.items('$section')]))"
}

get_mirrors()
{
    nd_config=`get_neurodebian_cfg`
#    $exe_dir/nd_querycfg -F" " --config-file="$nd_config" "mirrors" \
    query_cfg_section "$nd_config" "mirrors" \
    | while read mirror_name mirror_url; do
        # verify that url is just a url
        if echo "$mirror_url" | grep -v -e '^[a-z0-9:+]*://[-+_%.a-z0-9/]*$'; then
            print_verbose 1 "Mirror $mirror_name has 'illegit' URL: $mirror_url.  Skipping"
        fi
        echo "$mirror_name $mirror_url"
    done
}

netselect_mirror() {
    # select "closest" mirror according to netselect.
    print_verbose 2 "Selecting the 'best' mirror using netselect"
    if ! which netselect >/dev/null; then
        print_verbose 1 "netselect (apt-get install netselect) needed to select the 'best' mirror was not found"
        print_verbose 1 "Selecting the default repository: $nd_mirror_default"
        echo $nd_mirror_default
    else
        get_mirrors | awk '{print $2;}' | $ae_sudo xargs netselect -D -s 1 | awk '{print $2;}'
    fi
}

get_mirror_url() {
    # given mirror alias -- find its url
    url=$(get_mirrors | awk "/^$1 /{print \$2;}")
    if [ -z "$url" ]; then
        error 9 "Cannot resolve mirror $1 to the URL"
    fi
    echo $url
}

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,print-best-mirror -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"

if [ `whoami` != "root" ]; then
    ae_sudo=sudo
fi

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;;
      -m|--mirror) shift;  ae_mirror="$1"; shift;;
         --print-mirrors)  get_mirrors; exit 0;;
         --print-best-mirror)  netselect_mirror; 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

# Inform!
[ -z "$ae_sudo" ] || print_verbose 1 "This script requires root access.  Since current user is not root, sudo will be used"

#
# Basic system/environment knowledge
#

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

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
#

# knowing mirror is 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 "$ae_mirror" ]; then # none specified
        ae_mirror_url=$nd_mirror_origin
    else
        if ! [[ "$ae_mirror" =~ ".*://.*" ]]; then
            case "$ae_mirror" in
                best)    ae_mirror_url=$(netselect_mirror);;
                default) ae_mirror_url=$nd_mirror_default;;
                origin)  ae_mirror_url=$nd_mirror_origin;;
                *)       ae_mirror_url=$(get_mirror_url "$ae_mirror");;
            esac
        else
            ae_mirror_url="$ae_mirror" # it was some kind of a URL already
        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" ]; then
    apt-cache showsrc apt >&/dev/null && ae_sources=1 || ae_sources=0
fi

if [ $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
    if diff "$ae_output_file" <(echo "$apt_list") | grep -q .; then
        # error 3
        print_verbose 1 "File $ae_output_file already exists, containing:\n`cat \"$ae_output_file\"`\n\nI: New configuration is different:\n$apt_list"
        if get_apt_policy NeuroDebian >/dev/null; then
            print_verbose 1 "NeuroDebian repositories are already available, thus skipping the rest."
            print_verbose 1 "Rerun with --overwrite if you would like to reconfigure."
            exit 0
        else
            print_verbose 1 "NeuroDebian configuration is found but not yet available -- continuing with new configuration."
        fi
    else
        print_verbose 1 "New configuration is identical to existing and NeuroDebian repository is already enabled."
        print_verbose 1 "Skiping the rest. Rerun with --overwrite if you would like to reconfigure."
        exit 0
    fi
else
    print_verbose 1 "Generating $ae_output_file"
    if [ -z "$ae_dry_run" ]; then
        echo "$apt_list" | $ae_sudo bash -c "cat - >| '$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 "$ae_dry_run" ]; then
    apt_logfile="$ae_tempdir/apt.log"
    $ae_sudo apt-get update 1>"$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