#!/bin/bash
#
# cqfd - a tool to wrap commands in controlled Docker containers
#
# Copyright (C) 2015-2016 Savoir-faire Linux, Inc.
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

set -e

PROGNAME=`basename $0`
cqfd_dir=".cqfd"
dockerfile="$cqfd_dir/docker/Dockerfile"
cqfdrc=".cqfdrc"

## usage() - print usage on stdout
usage() {
    cat <<EOF
Usage: $PROGNAME [OPTION ARGUMENT] [COMMAND] [ARGUMENTS]

Options:
    -f <file>           Use file as config file (default .cqfdrc)
    -d <dir>            Use directory as cqfd directory (default .cqfd)
    -b <flavor_name>    Target a specific build flavor.

Commands:
    init     Initialize project build container
    run      Run argument(s) inside build container
    release  Run argument(s) and release software
    help     Show this help text

    By default, run is assumed, and the run command is the one
    configured in .cqfdrc.

    cqfd is Copyright (C) 2015-2016 Savoir-faire Linux, Inc.

    This program comes with ABSOLUTELY NO WARRANTY. This is free
    software, and you are welcome to redistribute it under the terms
    of the GNU GPLv3 license; see the LICENSE for more informations.
EOF
}

# cfg_parser() - parse ini-style config files
# Will parse a ini-style config file, and evaluate it to a bash array.
#   Ref: http://theoldschooldevops.com/2008/02/09/bash-ini-parser/
# arg$1: path to ini file
cfg_parser() {
    # bash 4.3 and later break compatibility
    if [ $BASH_VERSINFO -ge 4 -a ${BASH_VERSINFO[1]} -gt 2 ]; then
        local compat=1
        shopt -s compat42
    fi

    if ! ini="$(<$1)"; then           # read the file
        die "$1: No such file!"
    fi
    ini="${ini//[/\[}"          # escape [
    ini="${ini//]/\]}"          # escape ]
    IFS=$'\n' && ini=( ${ini} ) # convert to line-array
    ini=( ${ini[*]//;*/} )      # remove comments with ;
    ini=( ${ini[*]/\    =/=} )  # remove tabs before =
    ini=( ${ini[*]/=\   /=} )   # remove tabs be =
    ini=( ${ini[*]/\ =\ /=} )   # remove anything with a space around =
    ini=( ${ini[*]/#\\[/\}$'\n'cfg.section.} ) # set section prefix
    ini=( ${ini[*]/%\\]/ \(} )  # convert text2function (1)
    ini=( ${ini[*]/=/=\( } )    # convert item to array
    ini=( ${ini[*]/%/ \)} )     # close array parenthesis
    ini=( ${ini[*]/%\\ \)/ \\} ) # the multiline trick
    ini=( ${ini[*]/%\( \)/\(\) \{} ) # convert text2function (2)
    ini=( ${ini[*]/%\} \)/\}} ) # remove extra parenthesis
    ini[0]="" # remove first element
    ini[${#ini[*]} + 1]='}'    # add the last brace
    if ! eval "$(echo "${ini[*]}")" 2>/dev/null; then # eval the result
        die "$1: Invalid ini-file!"
    fi

    # restore previous bash behaviour
    [ "$compat" = "1" ] && shopt -u compat42
}

## die() - exit when an error occured
# $@ messages and variables shown in the error message
die() {
    echo "cqfd: fatal: $@" 1>&2
    exit 1
}

# docker_build() - Initialize build container
docker_build() {
    config_load
    if [ ! -f $dockerfile ]; then
        die "no Dockerfile found at location $dockerfile"
    fi
    docker build -q -t "$docker_img_name" `dirname $dockerfile`
}

# docker_run() - run command in configured container
# A few implementation details:
#
# - The user executing the build commands inside the container is
#   named 'builder', with the same uid/gid as your user to keep
#   filesystem permissions in sync.
#
# - Your project's source directory is always mapped to ~builder/src/
#
# - Your ~/.ssh directory is mapped to ~builder/.ssh to provide access
#   to the ssh keys (your build may pull authenticated git repos for
#   example).
#
# arg$1: the command string to execute as builder
#
docker_run() {
    [ -z "$JENKINS_URL" ] && local nojenkins=1

    # The user may set the CQFD_EXTRA_VOLUMES environment variable
    # to map custom volumes inside his development container.
    if [ -n "$CQFD_EXTRA_VOLUMES" ]; then
        local map extravol
        for map in $CQFD_EXTRA_VOLUMES; do
            extravol+="-v $map "
        done
    fi

    if [ -n "$CQFD_EXTRA_HOSTS" ]; then
        local map extrahosts
        for map in $CQFD_EXTRA_HOSTS; do
            extrahosts+="--add-host $map "
        done
    fi

    # CQFD_EXTRA_ENV is a space-separated list like VAR=value
    if [ -n "$CQFD_EXTRA_ENV" ]; then
        local map extraenv
        for map in $CQFD_EXTRA_ENV; do
            extraenv+="-e $map "
        done
    fi

    docker run --privileged -v "$PWD":/home/builder/src \
           -v ~/.ssh:/home/builder/.ssh \
           --rm \
           $extravol \
           $extrahosts \
           $extraenv \
           ${nojenkins:+ -ti} \
           ${SSH_AUTH_SOCK:+ -v $SSH_AUTH_SOCK:/home/builder/.sockets/ssh} \
           ${SSH_AUTH_SOCK:+ -e SSH_AUTH_SOCK=/home/builder/.sockets/ssh} \
           $docker_img_name \
           /bin/bash -c "groupadd -og $GROUPS -f builders && \
           useradd -s /bin/bash -u $UID -g $GROUPS builder && \
           chown $UID:$GROUPS /home/builder && \
           su builder -p -c \"cd ~builder/src/ && $1\" 2>&1"
}

# make_archive(): Create a release package.
# Note: the --transform option passed to tar allows to move all the
# specified files at the root of the archive. Therefore, you shouldn't
# include two files with the same name in the list of files to
# archive.
make_archive() {
    if [ -z "$release_files" ]; then
        die "No files to archive, check files in $cqfdrc"
    fi

    for file in $release_files; do
        [ -f $file ] || die "Cannot create release: missing $file"
    done

    # template the generated archive's filename
    local git_short=`git rev-parse --short HEAD 2>/dev/null`
    local git_long=`git rev-parse HEAD 2>/dev/null`
    local date_rfc3339=`date --rfc-3339='date'`

    # default name for the archive if not set
    [ -z "$release_archive" ] && release_archive="%Po-%Pn.tar.xz"

    release_archive=`echo $release_archive |
        sed -e 's!%%!%!g;
            s!%Gh!'$git_short'!g;
            s!%GH!'$git_long'!g;
            s!%D3!'$date_rfc3339'!g;
            s!%Po!'$project_org'!g;
            s!%Pn!'$project_name'!g;
            s!%Cf!'$flavor'!g;'`

    # also replace variable names - beware with eval
    eval release_archive=`echo $release_archive`

    XZ_OPT=-9 tar --transform "s/.*\///g" -cJf \
        "$release_archive" $release_files
}

# config_load() - load build settings from cqfdrc
# $1: optional "flavor" of the build, is a suffix of command.
config_load() {
    local p_flavor="$1"

    IFS="$IFS" cfg_parser "$cqfdrc"

    cfg.section.project # load the [project] section
    project_org="$org"
    project_name="$name"

    cfg.section.build # load the [build] section

    # build parameters may be overriden by a flavor defined in the
    # build section's 'flavors' parameter.
    if [ -n "$p_flavor" ]; then
        for flavor in $flavors; do
            if [ "$flavor" = "$p_flavor" ]; then
                local _found=1
                break
            fi
        done

        if [ -n "$_found" ]; then
            cfg.section."$p_flavor" # load the [$p_flavor] section
        else
            die "flavor \"$p_flavor\" not found in flavors list"
        fi
    fi

    build_cmd="$command"
    if [ -n "$distro" ]; then
        dockerfile="$cqfd_dir/$distro/Dockerfile"
    fi

    release_files="`eval echo $files`"
    release_archive="$archive"

    # This will look like fooinc_reponame
    if [ -n "$project_org" -a -n "$project_name" ]; then
        docker_img_name="${project_org}_${project_name}"
    else
        die "project.org and project.name not configured"
    fi
}

while [ $# -gt 0 ]; do
    case "$1" in
    help|-h|"--help")
        usage
        exit 0
        ;;
    init)
        docker_build
        exit $?
        ;;
    -b)
        shift
        flavor="$1"
        ;;
    -f)
        shift
        cqfdrc="$1"
        ;;
    -d)
        shift
        cqfd_dir="$1"
        dockerfile="$cqfd_dir/docker/Dockerfile"
        ;;
    run|release)
        [ "$1" = "release" ] && make_archive=1
        if [ $# -gt 1 ]; then
            shift
            build_cmd_alt="$@"
        fi
        break
        ;;
    ?*)
        die "Unknown command: $1"
        ;;
    *)
        # empty or no argument case
        ;;
    esac
    shift
done

config_load $flavor

if [ -n "$build_cmd_alt" ]; then
    build_cmd=$build_cmd_alt
elif [ -z "$build_cmd" ]; then
    die "No build.command defined in $cqfdrc !"
fi

docker_run "$build_cmd"

if [ "$make_archive" = "1" ]; then
    make_archive
fi