install-template

#!/usr/bin/env sh
set -eu

usage() {
    cat <<'EOF'
Usage:
  install-template [--template-dir PATH]
  install-template --local [PATH] [--template-dir PATH]
  install-template --branch BRANCH [--repo URL] [--template-dir PATH]
  install-template --commit COMMIT [--repo URL] [--template-dir PATH]

Installs the HyperBEAM Forge `rebar3 new device' template.

Options:
  --local [PATH]       Use a local HyperBEAM git checkout.
                       Defaults to the current working directory.
  --branch NAME        Use a branch from the HyperBEAM git repository.
                       Defaults to edge when no source option is given.
  --commit SHA         Use a commit from the HyperBEAM git repository.
  --repo URL           Git repository for --branch or --commit.
                       Defaults to https://github.com/permaweb/hyperbeam.git.
  --template-dir PATH  Rebar3 template directory.
                       Defaults to Rebar's user template directory.
  -h, --help           Show this help.
EOF
}

die() {
    printf '%s\n' "$*" >&2
    exit 1
}

quote() {
    printf '%s' "$1" | sed 's/\\/\\\\/g; s/"/\\"/g'
}

git_url() {
    case "$1" in
        /*) printf 'file://%s' "$1" ;;
        *) printf '%s' "$1" ;;
    esac
}

local_ref() {
    root="$1"
    commit="$(git -C "$root" rev-parse HEAD)"
    printf '{ref, "%s"}' "$(quote "$commit")"
}

script_dir() {
    cd "$(dirname "$0")" && pwd
}

rebar3_config_dir() {
    if [ "${XDG_CONFIG_HOME:-}" ]; then
        printf '%s/rebar3' "$XDG_CONFIG_HOME"
    else
        printf '%s/.config/rebar3' "$HOME"
    fi
}

rebar3_env_config_dir() {
    case "$1" in
        */.config/rebar3) printf '%s' "$1" ;;
        *) printf '%s/.config/rebar3' "$1" ;;
    esac
}

default_template_dir() {
    if [ "${REBAR_TEMPLATE_DIR:-}" ]; then
        printf '%s' "$REBAR_TEMPLATE_DIR"
    elif [ "${REBAR_GLOBAL_CONFIG_DIR:-}" ]; then
        printf '%s/templates' "$(rebar3_env_config_dir "$REBAR_GLOBAL_CONFIG_DIR")"
    elif [ "${REBAR_CACHE_DIR:-}" ]; then
        printf '%s/.config/rebar3/templates' "$REBAR_CACHE_DIR"
    else
        printf '%s/templates' "$(rebar3_config_dir)"
    fi
}

write_device_template() {
    path="$1"
    hb_dep="$2"
    hb_plugin="$3"
    prefix="$4"
    cat > "$path" <<EOF
{description, "HyperBEAM device project"}.
{variables, [
    {name, "my_device", "Device and OTP application name"},
    {hb_dep,
        "$(quote "$hb_dep")",
        "HyperBEAM dependency term"},
    {hb_plugin,
        "$(quote "$hb_plugin")",
        "HyperBEAM Forge plugin term"}
]}.

{template, "${prefix}_rebar.config", "{{name}}/rebar.config"}.
{template, "${prefix}_src/device.app.src", "{{name}}/src/{{name}}.app.src"}.
{template, "${prefix}_src/dev_device.erl.in", "{{name}}/src/dev_{{name}}.erl"}.
{template, "${prefix}_README.md", "{{name}}/README.md"}.
{template, "${prefix}_.gitignore", "{{name}}/.gitignore"}.
EOF
}

render_shared_rebar_config() {
    path="$1"
    shared_config="$2"
    out="$3"
    # reason: generated device repos cannot read files from this repo when their
    # rebar.config loads, so render shared_rebar.config inline.
    while IFS= read -r line; do
        case "$line" in
            *"{{hb_shared_rebar_config}}"*) cat "$shared_config" ;;
            *) printf '%s\n' "$line" ;;
        esac
    done < "$path" > "$out"
    mv "$out" "$path"
}

install_template() {
    template_dir="$1"
    hb_dep="$2"
    hb_plugin="$3"
    root="$(script_dir)"
    src="$root/src/forge/plugin/priv"
    shared_rebar_config="$root/shared_rebar.config"
    support="$template_dir/hyperbeam-device"
    tmp="$support.tmp.$$"
    template="$template_dir/device.template"
    template_tmp="$template.tmp.$$"

    rm -rf "$tmp"
    mkdir -p "$tmp"
    cp -R "$src/." "$tmp"
    rm -f "$tmp/device.template"
    render_shared_rebar_config \
        "$tmp/_rebar.config" \
        "$shared_rebar_config" \
        "$tmp/_rebar.config.rendered"
    write_device_template \
        "$template_tmp" \
        "$hb_dep" \
        "$hb_plugin" \
        "hyperbeam-device/"
    rm -rf "$support"
    mv "$tmp" "$support"
    mv "$template_tmp" "$template"
}

repo_url="https://github.com/permaweb/hyperbeam.git"
template_dir="$(default_template_dir)"
mode="branch"
value="edge"

while [ "$#" -gt 0 ]; do
    case "$1" in
        --local)
            mode="local"
            if [ "${2:-}" ] && [ "${2#--}" = "$2" ]; then
                value="$2"
                shift
            else
                value="$(pwd)"
            fi
            ;;
        --branch)
            [ "$#" -ge 2 ] || die "--branch requires a value"
            mode="branch"
            value="$2"
            shift
            ;;
        --commit)
            [ "$#" -ge 2 ] || die "--commit requires a value"
            mode="commit"
            value="$2"
            shift
            ;;
        --repo)
            [ "$#" -ge 2 ] || die "--repo requires a value"
            repo_url="$2"
            shift
            ;;
        --template-dir)
            [ "$#" -ge 2 ] || die "--template-dir requires a value"
            template_dir="$2"
            shift
            ;;
        -h|--help)
            usage
            exit 0
            ;;
        *)
            die "unknown option: $1"
            ;;
    esac
    shift
done

case "$mode" in
    local)
        root="$(cd "$value" && pwd)"
        [ -d "$root/src/forge/plugin" ] ||
            die "could not find $root/src/forge/plugin"
        if ! git -C "$root" diff --quiet ||
            ! git -C "$root" diff --cached --quiet; then
            printf 'warning: --local uses committed HEAD; '
            printf 'uncommitted changes are not included\n'
        fi
        source_url="$(git_url "$root")"
        source_ref="$(local_ref "$root")"
        ;;
    branch)
        source_url="$repo_url"
        source_ref="{branch, \"$(quote "$value")\"}"
        ;;
    commit)
        source_url="$repo_url"
        source_ref="{ref, \"$(quote "$value")\"}"
        ;;
esac

hb_dep="{git, \"$(quote "$source_url")\", $source_ref}"
hb_plugin="{git_subdir, \"$(quote "$source_url")\", $source_ref, \"src/forge\"}"

install_template "$template_dir" "$hb_dep" "$hb_plugin"
printf 'Installed HyperBEAM Forge template in %s\n' "$template_dir"
printf 'Generated projects will use %s at %s\n' "$source_url" "$source_ref"
printf 'Try: rebar3 new device name=my_device\n'