#!/usr/bin/env dash

NAME="$0"

note() {
    local IFS=" "
    printf "%s\n" "$*"
}

warn() {
    note "$@" >&2
}

die() {
    warn "$NAME:" "$@"
    #cleanup
    exit 1
}

cleanup() {
    :
    #[ ! -e temp.tar.gz ] || rm temp.tar.gz || die failed
    #[ ! -d temp ] || rm -r temp || die failed
}

backup() {
    if [ -e "${1}~" ]; then
        backup "${1}~" || die 'failed to backup file' "$1"
    fi
    mv "$1" "${1}~" || die 'failed to backup file' "$1"
}

rc="$(readlink -f "$(dirname "$NAME")" )"
[ -d "$rc" ] || die 'failed to determine rc directory'
cd "$rc" || die 'failed to change directory'

if ! which git >/dev/null 2>&1; then
    [ "$1" != commit ] || die 'git not found'

    # git unavailable. just document everything as it is.
    dash ./sh/document || die 'failed to generate documentation'
    printf '%s\n' '' '## compatibility' '' >> README.md~ || die 'failed to make room for compatibility table'
    dash ./tableize >> README.md~ || die 'failed to generate compatibility table'

elif [ "$1" = local ]; then
    # user requested to ignore git.
    dash ./sh/document || die 'failed to generate documentation'
    printf '%s\n' '' '## compatibility' '' >> README.md~ || die 'failed to make room for compatibility table'
    dash ./tableize >> README.md~ || die 'failed to generate compatibility table'

else
    # git available. document the most recent commit, without pending changes.

    [ ! -e temp.tar.gz ] || backup temp.tar.gz || die 'failed to backup existing temp archive'
    git archive --prefix=temp/ HEAD -o temp.tar.gz || die 'failed to create git archive'

    [ ! -e temp ] || backup temp || die 'failed to backup existing temp directory'
    tar -zxf temp.tar.gz || die 'failed to unarchive temp archive'

    #( cd temp; HOME="$rc/temp" dash ./install )
    ln temp/home/zshrc temp/.zshrc || die 'failed to copy files'
    ln temp/home/shrc temp/.shrc || die 'failed to copy files'
    ln temp/home/bashrc temp/.bashrc || die 'failed to copy files'

    # use new documentation-generating scripts on old shell scripts.
    cp -p README.md temp/README.md || die 'failed to copy existing readme'
    dash ./sh/document temp || die 'failed to generate documentation'
    printf '%s\n' '' '## compatibility' '' >> temp/README.md~ || die 'failed to make room for compatibility table'
    dash ./tableize temp >> temp/README.md~ || die 'failed to generate compatibility table'

    #[ ! -e README.md ] || backup README.md || die 'failed to backup existing readme'
    mv temp/README.md~ README.md~ || die 'failed to move generated readme'

    rm temp.tar.gz || die 'failed to clean up temp archive'
    rm -r temp || die 'failed to clean up temp directory'

    if [ "$1" = commit ]; then
        mv README.md~ README.md || die 'failed to overwrite readme'
        git commit README.md -m 'regenerate readme' || die 'failed to commit'
    fi
fi