#!/bin/bash -e
# This is a tool to automatically generate and ship client updates.
# It is entirely self-contained, storing its own state in the git repo.
# It is called by running 'make updates' in server-data.
# It also supports manually calls for maintenance work.
# TODO: make auto-mode work with music too.

# local branch to keep update info on
# will be created on first run; updated thereafter
branch=update-zips
# must already exist
# must NOT be a relative path
output=~/www/updates

function apply_function()
{
    $1  misc        *.* COPYING rules/
    $1  emotes      graphics/emotes/
    $1  images      graphics/images/
    $1  items       graphics/items/
    $1  minimaps    graphics/minimaps/
    $1  particles   graphics/particles/
    $1  skills      graphics/skills/
    $1  sprites     graphics/sprites/
    $1  tiles       graphics/tiles/
    $1  items       items/
    $1  maps        maps/
    $1  mob         monsters/
    $1  npc         npcs/
    $1  sfx         sfx/
    $1  tsx         tilesets/
}

function add_resource()
{
    pushd $output >/dev/null
    adler32 $1 | tee -a resources2.txt | {
        read name hash
        chmod a+r $name
        sed '/<\/updates>/i    <update type="data" file="'$name'" hash="'$hash'" />' -i resources.xml
    }
    popd >/dev/null
}

function add_music()
{
    pushd $output >/dev/null
    adler32 $1 | {
        read name hash
        chmod a+r $name
        sed '/<\/updates>/i    <update type="music" required="no" file="'$name'" hash="'$hash'" />' -i resources.xml
    }
    popd >/dev/null
}

function do_initial_zip()
{
    zip=$1-$this_update.zip; shift
    git ls-files --with-tree=HEAD -- "$@" \
        | zip -q $output/$zip -@
    add_resource $zip
}
function do_initial_music()
{
    zip=music-$this_update.zip
    ( cd music/ ; git ls-files --with-tree=HEAD ) \
        | sed 's:^:music/:' \
        | zip -q $output/$zip -@
    add_music $zip
}

function git_diff_tree()
{
    git diff-tree -r --diff-filter=AM "$@"
}

function do_delta_zip()
{
    zip=$1-$last_update..$this_update.zip; shift
    if git_diff_tree  --quiet $last_update $this_update -- "$@"
    then
        return
    fi
    git_diff_tree --name-only $last_update $this_update -- "$@" \
        | zip -q $output/$zip -@
    add_resource $zip
}
function do_delta_music()
{
    zip=music-$last_update..$this_update.zip
    if (cd music; git_diff_tree  --quiet $last_update $this_update )
    then
        return
    fi
    (cd music; git_diff_tree --name-only $last_update $this_update ) \
        | sed 's:^:music/:' \
        | zip -q $output/$zip -@
    add_music $zip
}

function do_initial_zips()
{
    apply_function do_initial_zip
}

function do_delta_zips()
{
    apply_function do_delta_zip
}

function main()
{
    if ! test -d $output
    then
        echo 'Fatal error: output directory does not exist'
        echo "$output"
        return 1
    fi
    if ! test -f $output/resources.xml
    then
        (
            echo '<?xml version="1.0"?>'
            echo '<updates>'
            echo '</updates>'
        ) > $output/resources.xml
    fi

    this_update=$(git rev-parse --short HEAD)
    if ! last_update=$(git rev-parse --short $branch 2>/dev/null)
    then
        echo 'Doing initial updates'
        do_initial_zips
    elif test "$this_update" = "$last_update"
    then
        echo 'No commits since last update generation ...'
    else
        echo 'Doing incremental updates'
        do_delta_zips
    fi
    git branch -f $branch

    this_update=$(cd music; git rev-parse --short HEAD)
    if ! last_update=$(cd music; git rev-parse --short $branch 2>/dev/null)
    then
        echo 'Doing initial music updates'
        do_initial_music
    elif test "$this_update" = "$last_update"
    then
        echo 'No commits since last music update generation ...'
    else
        echo 'Doing incremental music updates'
        do_delta_music
    fi
    ( cd music; git branch -f $branch )
}

if test "$0" = "$BASH_SOURCE"
then
    echo 'Generating updates automatically'
    main
else
    echo 'sourcing detected - you can do manual updates'
fi