#!/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 () {
    echo "updating installation status"
    for ac in $(sqlite_request 'select printf("%i:%s/%s", aircrafts.id, aircrafts.name, setxml.file) from aircrafts inner join setxml where aircrafts.id = setxml.variantof;'); do
        ac_path=${ac#*:}
        test ! -e $fgaddon_path/$ac_path
        installed=$?
        sqlite_request "update setxml set installed = $installed where file = '${ac_path#*/}' and variantof = ${ac%:*}"
    done
    if test -r "$database" && md5sum $in_ram_database | sed "s,$in_ram_database,$database," | md5sum --status -c -; then
        rm -f $in_ram_database
        echo "no changes in $database"
    elif test -w "$database"; then
        mv -f $in_ram_database "$database"
        echo "database $database updated"
    elif ! test -e "$database"; then
        mv $in_ram_database "$database"
        echo "database $database created"
    else
        rm -f $in_ram_database
        echo "nothing can be done with $database !"
    fi
    rm -f $aircrafts $aircraft $setxml
}

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

    dbupdate=$(sqlite_request "select revision from aircrafts where name is '$ac'")
    if test -z "$dbupdate"; then
        sqlite_request "insert into aircrafts (name, revision, date, author) values ('$ac', $revision, $revdate, '$revauthor')"
    elif test $dbupdate -lt $revision; then
        sqlite_request "update aircrafts set revision = $revision, author = '$revauthor' 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

        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
            test ! -e $fgaddon_path/$ac/$sx
            installed=$?
            sqlite_request "insert into setxml values ('$sx', $id, '$description', '$long_description', '$author', '$type', '$flight_model', $installed)"
        fi
    done
}

xmlgetnext () {
   local IFS='>'
   read -d '<' TAG VALUE
}

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, revision integer, date integer, author text)"
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 | sed -n '/<table>/,/<\/table>/p' > $aircrafts

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

        while xmlgetnext; do
            case "$TAG" in
                'tr')
                    unset ac revision revauthor
                    ;;
                'a class="icon" href='*)
                    eval $(echo "${TAG#* }")
                    ac=$href
                    ;;
                'span title='*)
                    eval $(echo "${TAG#* }")
                    revdate=$(date +%s -d "$title")
                    ;;
                'a href="/p/flightgear/fgaddon/'*)
                    eval $(echo "${TAG#* }")
                    revision=$(tr -cd '[:digit:]' <<< $href)
                    ;;
                'span class="icon emboss x16" style="text-align:center;" title="User"'*)
                    user=1
                    ;;
                '/span')
                    test -n "$user" && revauthor=$(tr -cd '[:alnum:]' <<< $VALUE) && unset user
                    ;;
                '/tr')
                    test -n "$revision" -a -n "$revauthor" -a -n "$ac" -a -n "$revdate" && update_database
                    ;;
            esac
        done < $aircrafts
    ;;
    'rss')
        get_updates_from_rss () {
            while xmlgetnext; do
                case "$TAG" in
                    'item')
                        let entry++
                        unset link revdate revauthor revision title;;
                    'link')
                        link="$VALUE";;
                    'title')
                        title="$VALUE";;
                    'dc:creator'*)
                        revauthor="$VALUE";;
                    'guid isPermaLink="false"')
                        revision=$(sed -r 's,^.+/([0-9]+)/$,\1,' <<< $VALUE)
                        if test $entry -eq 1 -a $revision -eq ${latest_revision:-0}; then
                            echo "no new updates" >&2
                            break
                        fi
                    ;;
                    'pubDate')
                        revdate=$(date +%s -d "$VALUE")
                    ;;
                    '/item')
                        echo "$revision ($(date +"%d %B" -d@$revdate), $revauthor): $title" >&2
                        wget -qO- "$link" | awk -v data="revision=$revision revdate=$revdate revauthor=$revauthor" '
                            />\/trunk\/Aircraft\/.+</ {
                                ac[gensub("^.+>/trunk/Aircraft/([^/]+).+<.*$", "ac=\\1", "1", $0)]++
                            }
                            END {
                                for (i in ac) print data " " i
                            }'
                    ;;
                    '/channel')
                        if test ${latest_revision:-0} -lt $revision; then
                            echo "WARNING: $(( ($revision - ${latest_revision:-0}) )) revisions between the oldest RSS entry and last DB entry" >&2
                            echo "a \`$0 full' may be useful" >&2
                        fi
                    ;;
                esac
            done < $aircrafts | awk '
                {
                    if (a[$4] == "") a[$4]=$0
                }
                END {
                    for (i in a) {
                        total++
                        command = command a[i] " update_database;"
                    }
                    printf("total=%i;%s", total, command)
                }'
        }
        latest_revision=$(sqlite_request "select max(revision) from aircrafts")
        wget -qO- https://sourceforge.net/p/flightgear/fgaddon/feed > $aircrafts
        eval "$(get_updates_from_rss)"
    ;;
        *)
            echo "usage: [DB=path/to/database] $0 [rss|full]"
            echo
            echo "rss: updates only last repo changes"
            echo "full: updates from all repo"
            exit 1
    ;;
esac