#!/bin/bash

fgaddon_url=https://sourceforge.net/p/flightgear/fgaddon/HEAD/tree/trunk/Aircraft
fgaddon_svn=https://svn.code.sf.net/p/flightgear/fgaddon/trunk/Aircraft
fgaddon_path=$HOME/.fgfs/flightgear-addons/Aircraft

attribute_regex='s/^.*id="l[0-9]+" class="code_block">.*<span class="nt">&lt;__attribute__&gt;<.span>(.+)<span class="nt">&lt;.__attribute__&gt;<.span>.*$/\1/p'

aircrafts=$(mktemp --dry-run /dev/shm/Aircraft-XXXXXXXXX)
aircraft=$(mktemp --dry-run /dev/shm/aircraft-XXXXXXX)
setxml=$(mktemp --dry-run /dev/shm/setxml-XXXXXXXX)
in_ram_database=$(mktemp --dry-run /dev/shm/XXXXXXX)
database=${DB:-$0.db}

attributes=(description long_description author flight_model)

function get_attribute () {
    eval "unset $1"
    result=$(sed -rn "${attribute_regex//__attribute__/${1//_/-}}" $setxml)
    eval "$1=\$\"$result\""
}

function sqlite_request () {
    sqlite3 "$in_ram_database" <<< "$1"
}

function trap_exit () {
    if test -r "$database" && md5sum $in_ram_database | sed "s,$in_ram_database,$database," | md5sum --status -c -; then
        rm -f $in_ram_database
    elif test -w "$database"; then
        mv -f $in_ram_database "$database"
    elif ! test -e "$database"; then
        mv $in_ram_database "$database"
    else
        rm -f $in_ram_database
    fi
    rm -f $aircrafts $aircraft $setxml
}

update_database () {
    let progress++
    echo "[ ${progress}${total:+/$total} ] $ac"

    dbupdate=$(sqlite_request "select date from aircrafts where name is '$ac'")
    if test -z "$dbupdate"; then
        sqlite_request "insert into aircrafts (name, date) values ('$ac', $update)"
    elif test $dbupdate -ne $update; then
        sqlite_request "update aircrafts set date = $update where name is '$ac'"
    fi
    id=$(sqlite_request "select id from aircrafts where name is '$ac'")

    wget -qO- $fgaddon_url/$ac > $aircraft
    for sx in $(sed -rn 's/<a class="icon" href="(.+-set.xml)" title=".+"><i class="fa fa-file-o">.+$/\1/p' $aircraft); do
        echo " -> ${sx/-set.xml}"
        wget -qO- $fgaddon_url/$ac/$sx > $setxml
        for attribute in ${attributes[@]}; do
            get_attribute $attribute
        done

        test -e $fgaddon_path/$ac/$sx
        installed=$?

        if test -n "$description" -a -z "$flight_model"; then
            grep -qi 'jsbsim' <<< "$description" && flight_model='jsb'
            grep -qi 'yasim' <<< "$description" && flight_model='yasim'
        fi

        known=$(sqlite_request "select variantof from setxml where file is '$sx'")
        if test -n "$known"; then
            for attribute in ${attributes[@]}; do
                dbvalue=$(sqlite_request "select $attribute from setxml where file is '$sx'")
                eval "wgvalue=\$$attribute"
                if test "$dbvalue" != "$wgvalue"; then
                    sqlite_request "update setxml set $attribute = '$wgvalue' where file is '$sx'"
                fi
            done
        else
            sqlite_request "insert into setxml values ('$sx', $id, '$description', '$long_description', '$author', '$type', '$flight_model', $installed)"
        fi
    done
}

trap trap_exit EXIT

test -e $database && cp $database $in_ram_database

sqlite_request "create table if not exists aircrafts (id integer primary key, name text, date integer)"
sqlite_request "create table if not exists setxml (file text, variantof integer, description text, long_description text, author text, type text, flight_model text, installed integer)"

test -z "$1" && echo "mode RSS"

case ${1:-rss} in
    'full')
        echo "downloading the FGADDON list"
        wget -qO- $fgaddon_url > $aircrafts

        total=$(grep -c '<a class="icon" href=".*class="fa fa-folder".*i>&nbsp;' $aircrafts)

        for ac in $(sed -rn 's/^\s*<a class="icon" href="(.+)" title=.* class="fa fa-folder".+$/\1/p' $aircrafts); do
            update=$(grep -A3 '<a class="icon" href=".*class="fa fa-folder".*i>&nbsp;'$ac'<' $aircrafts | sed -rn '$s/^\s*<span title="(.+)">.*$/\1/p')
            update=$(date +%s -d"$update")
            update_database
        done
    ;;
    'rss')
        xmlgetnext () {                                                         
           local IFS='>'
           read -d '<' TAG VALUE
        }

        get_updates_from_rss () {
            wget -qO- https://sourceforge.net/p/flightgear/fgaddon/feed | while xmlgetnext; do
                case "$TAG" in
                    'item')
                        let entry++
                        unset link pubDate revision title file;;
                    'link')
                        link="$VALUE";;
                    'title')
                        title="$VALUE";;
                    'guid isPermaLink="false"')
                        revision=$(sed -r 's,^.+/([0-9]+)/$,\1,' <<< $VALUE);;
                    'pubDate')
                        pubDate=$(date +%s -d "$VALUE")
                        if test $entry -eq 1 -a $pubDate -eq ${latest_update:-0}; then
                            echo "no new updates" >&2
                            break
                        fi
                    ;;
                    '/item')
                        echo "checking $revision ($(date +"%d %B" -d@$pubDate)): $title" >&2
                        wget -qO- "$link" > $aircrafts
                        for file in $(egrep '/trunk/Aircraft/.*/.*-set.xml$' $aircrafts); do
                            file=${file/\/trunk\/Aircraft\/}
                            echo ${file%/*}
                            echo $pubDate
                        done
                    ;;
                    '/channel')
                        if test ${latest_update:-0} -lt $pubDate; then
                            echo "WARNING: $(( ($pubDate - ${latest_update:-0}) / 86400 )) days between the oldest RSS entry and last DB entry" >&2
                            echo "a $0 full may be useful" >&2
                        fi
                    ;;
                esac
            done
        }
        latest_update=$(sqlite_request "select max(date) from aircrafts")
        ac_list=($(get_updates_from_rss))
        total=$(( ${#ac_list[@]} / 2 ))
        for ((i=0; i < ${#ac_list[@]}; i=i+2)); do
            ac=${ac_list[i]}
            update=${ac_list[i+1]}
            update_database
        done
    ;;
        *)
            echo "usage: [DB=path/to/database] $0 [rss|full]"
            echo
            echo "rss: updates only last repo changes"
            echo "full: updates from all repo"
    ;;
esac