#!/bin/bash
#
# nginx_verify_site.sh
#
# Copyright (C) 2015, Branko Majic <branko@majic.rs>
#
# 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/>.
#

program="nginx_verify_site.sh"
version="0.1"

function usage() {
    cat <<EOF
$program $version, a non-interactive utility for testing a new nginx site configuration file

Usage: $program [OPTIONS] site_configuration_file

$program is a non-interactive utility for testing a new nginx site configuration
file. The utility works by copying the existing nginx configuration to a
temporary path, deploying the passed-in site configuration file to the temporary
location, and running the nginx -t command on temporary configuration
copy. During this process the utility will also fix the paths in temporary
configuration files on the fly.

A single positional argument is accepted:

site_configuration_file
  Path to the (new) file containing the site configuration that should be
  tested.

$program accepts the following options:

    -n name   Name to use for site configuration file. Useful when combined with
              Ansible's validate command (modules copy/template) which does not
              preserve filenames when executed. Defaults to original filename
              for site_configuration_file.

    -v        show script version and licensing information
    -h        show usage help


Please report bugs and send feature requests to <branko@majic.rs>.
EOF
}

function version() {
        cat <<EOF
$program, version $version

+-----------------------------------------------------------------------+
| Copyright (C) 2015, Branko Majic <branko@majic.rs>                    |
|                                                                       |
| 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/>. |
+-----------------------------------------------------------------------+

EOF
}

# Set-up colours for message printing if we're not piping and terminal is
# capable of outputting the colors.
_color_terminal=$(tput colors 2>&1)
if [[ -t 1 ]] && (( ${_color_terminal} > 0 )); then
    _text_bold=$(tput bold)
    _text_white=$(tput setaf 7)
    _text_blue=$(tput setaf 6)
    _text_green=$(tput setaf 2)
    _text_yellow=$(tput setaf 3)
    _text_red=$(tput setaf 1)
    _text_reset=$(tput sgr0)
else
    _text_bold=""
    _text_white=""
    _text_blue=""
    _text_green=""
    _text_yellow=""
    _text_red=""
    _text_reset=""
fi

# Set-up functions for printing coloured messages.
function debug() {
    echo "${_text_bold}${_text_blue}[DEBUG]${_text_reset}" "$@"
}

function info() {
    echo "${_text_bold}${_text_white}[INFO] ${_text_reset}" "$@"
}

function success() {
    echo "${_text_bold}${_text_green}[OK]   ${_text_reset}" "$@"
}

function warning() {
    echo "${_text_bold}${_text_yellow}[WARN] ${_text_reset}" "$@"
}

function error() {
    echo "${_text_bold}${_text_red}[ERROR]${_text_reset}" "$@" >&2
}

# Helper function for removing temporary directory.
function remove_temp_config() {
    [[ -e $temp_config ]] && rm -rf "$temp_config"
}

# If no arguments were given, just show usage help.
if [[ -z $1 ]]; then
    usage
    exit 0
fi

# Parse the arguments
while getopts "n:vh" opt; do
    case "$opt" in
        n) name="$OPTARG";;
        v) version
           exit 0;;
        h) usage
           exit 0;;
        *) usage
           exit 1;;
    esac
done
i=$OPTIND
shift $(($i-1))

# Read the site configuration.
site_configuration_file="$1"

# Verify positional arguments.
if [[ ! -f $site_configuration_file ]]; then
    error "Could not open site configuration file: $site_configuration_file"
    exit 1
fi

# Determine what the file should be called like in temporary directory. Sanitise
# the name if it was passed in, just in case.
if [[ -z $name ]]; then
    name=$(basename "$site_configuration_file")
else
    name=$(basename "$name")
fi

# Set-up paths where original and temporary configurations can be found.
original_config="/etc/nginx"
temp_config=$(mktemp -d)

# Remove the temporary directory on exit.
trap remove_temp_config EXIT

# Prepare temporary copy for verification.
cp -a "$original_config" "$temp_config/"
find "$temp_config" -type f -print0 | xargs -0 sed -i -e "s#$original_config#$temp_config/nginx#g"

# Enable the new site configuration in temporary copy.
rm -f "$temp_config/nginx/sites-enabled/$name"
cp "$site_configuration_file" "$temp_config/nginx/sites-enabled/$name"

# Finally, run the test.
nginx -t -c "$temp_config/nginx/nginx.conf"