#!/bin/bash
# vim: set ft=sh :

set -ue

ROOT=$(pwd)

BIN=bin
PROCESS_ZONE=$BIN/process-zone
EXPAND_ZONE=$BIN/expand-zone
UPDATE_SERIAL=$BIN/update-serial

SETTINGS=settings
ZONES=zones
SERIALS=serials

PROCESS_ARGS='--input-charset latin-1'

FORWARD_MX=mail
REVERSE_ZONE=194.197.235
REVERSE_DOMAIN=paivola.fi

## options
IS_TTY=
UPDATE_FORCE=
SERIAL_NOUPDATE=

function help_args {
    local prog=$1

    cat <<END
Usage: $prog [options]

    -h      display this help text
    -F      force-updates without checking src mtime
    -S      do not update serial
END
}

function parse_args {
    OPTIND=1

    while getopts 'hFS' opt "$@"; do
        case $opt in
            h)  
                help_args $1
                exit 0
            ;;

            F)  UPDATE_FORCE=y ;;
            S)  SERIAL_NOUPDATE=y ;;
            
            ?)  
                die 
            ;;
        esac

    done
}

## lib
function log_msg {
    echo "$*" >&2
}

function log_color {
    local code=$1; shift

    if [ $IS_TTY ]; then
        echo $'\e[0;'${code}'m'"$*"$'\e[00m' >&2
    else
        echo "$*" >&2
    fi
}

function log_error {
    log_color 31 "$*"
}

function log {
    log_msg "$*"
}

function log_info {
    log_color 36 "  $*"
}

function log_debug {
    log_color 32 "    $*"
}

function log_cmd {
    log_color 35 "       \$ $*"
}

function die {
    log_error "$*"
    exit 1
}

function cmd {
    log_cmd "$@"

    "$@" || die "Failed"
}

function run_cmd {
    local msg=$1; shift

    log_info "$msg... "

    cmd "$@"
}

function indent () {
    "$@" | (
        while read line; do
            echo "    $line"
        done
    ) || exit $?
}

## test
[ -d $SETTINGS ] || die "Missing settings: $SETTINGS"
[ -d $SERIALS ] || die "Missing serials: $SERIALS"
[ -d $ZONES ] || die "Missing zones: $ZONES"

## functions
function update {
    local dst=$1
    local src=$2
    local tmp=$dst.new

    shift 2

    if [ -z $src ] || [ $UPDATE_FORCE ] || [ $dst -ot $src ]; then
        log_debug "update: $dst <- $src"
        cmd "$@" $src > $tmp

        # compare
        if [ -e $dst ]; then
            # terse
            indent diff --unified=1 $dst $tmp
        fi
        
        # overwrite
        mv $tmp $dst

    else
        log_debug "$dst <- $src: up-to-date"
    fi
}

## bin wrappers
function update_serial {
    cmd $UPDATE_SERIAL $*
}

function expand_zone {
    local output=$1; shift
    local src=$1; shift


    update $output $src $EXPAND_ZONE "$@"
}

function process_zone {
    local output=$1; shift
    local src=$1; shift

    update $output $src $PROCESS_ZONE $PROCESS_ARGS "$@"
}

## actions
function copy_zone_part {
    local zone=$1
    local part=$2

    local name=$zone.zone.$part

    log_info "Copying zone $zone/$part: zones/$name"

    update $ZONES/$name $SETTINGS/$name cat
}

function update_zone {
    local zone=$1
    local name=$zone.zone

    log_info "Generating $zone zone headers: zones/$name" 

    expand_zone     $ZONES/$name    $SETTINGS/$zone.zone   \
        --serial $SERIALS/$zone.serial  \
        --expand zones=$ROOT/$ZONES
}

function update_zone_view {
    local zone=$1
    local view=$2

    local name=$view/$zone.zone

    log_info "Generating $zone:$view zone headers: zones/$name"

    expand_zone     $ZONES/$name    $SETTINGS/$zone.zone   \
        --serial $SERIALS/$zone.serial  \
        --expand zones=$ROOT/$ZONES     \
        --expand view=$view
}

function main {
    # test tty
    [ -t 1 ] && IS_TTY=y

    parse_args "$@"

    if [ $SERIAL_NOUPDATE ]; then
        log_debug "skipping serial-update"
    else
        log "Updating serials..."
            update_serial   $SERIALS/paivola.serial
            update_serial   $SERIALS/paivola-reverse.serial
    fi

    log "Generating host zones..."
        process_zone    $ZONES/external/paivola.zone.hosts  $SETTINGS/paivola.txt --forward-zone
        process_zone    $ZONES/internal/paivola.zone.hosts  $SETTINGS/paivola.txt --forward-zone --forward-txt --forward-mx $FORWARD_MX
        process_zone    $ZONES/paivola-reverse.zone.hosts   $SETTINGS/paivola.txt --reverse-zone $REVERSE_ZONE --reverse-domain $REVERSE_DOMAIN

    log "Copying zone parts..."
        copy_zone_part      paivola             auto
        copy_zone_part      paivola             services
        copy_zone_part      paivola             internal
        copy_zone_part      paivola             external

    log "Updating zones..."
        update_zone         paivola-reverse
        update_zone_view    paivola             internal
        update_zone_view    paivola             external
}

main "$@"