#!/usr/bin/env bash

set -eu

git_sha_head() {
    git rev-parse --short=8 HEAD
}

go_deps_sha() {
    bindir=$( cd "${BASH_SOURCE[0]%/*}" && pwd )
    rootdir=$( cd "$bindir"/.. && pwd )
    cat "$rootdir/go.mod" "$rootdir/Dockerfile-go-deps" | shasum - | awk '{print $1}' |cut -c 1-8
}

clean_head() {
    [ -n "${CI_FORCE_CLEAN:-}" ] || git diff-index --quiet HEAD --
}

named_tag() {
    tag="$(git name-rev --tags --name-only "$(git_sha_head)")"
    tag=${tag%"^0"}
    echo "${tag}"
}

head_root_tag() {
    if clean_head ; then
        clean_head_root_tag
    else
        name=${USER//[^[:alnum:].-]/}
        echo "dev-$(git_sha_head)-$name"
    fi
}

clean_head_root_tag() {
    if clean_head ; then
        if [ "$(named_tag)" != undefined ]; then
            named_tag
        else
            echo "git-$(git_sha_head)"
        fi
    else
        echo 'Commit unstaged changes.' >&2
        exit 3
    fi
}

validate_tag() {
    file=$1
    shift

    image=$1
    shift

    sha=$1
    shift

    dockerfile_tag=$(grep -oe "$image"':[^ ]*' "$file") || true
    deps_tag="$image:$sha"
    if [ -n "$dockerfile_tag" ] && [ "$dockerfile_tag" != "$deps_tag" ]; then
        echo "Tag in \"$file\" does not match source tree:
$dockerfile_tag (\"$file\")
$deps_tag (source)"
        return 3
    fi
}

# This function should be called by any docker-build-* script that relies on Go
# dependencies. To confirm the set of scripts that should call this function,
# run:
# $ grep -ER 'docker-build-go-deps' .

validate_go_deps_tag() {
    file=$1
    validate_tag "$file" gcr.io/linkerd-io/go-deps "$(go_deps_sha)"
}