#!/bin/sh
# SPDX-License-Identifier: Apache-2.0
# (c) 2024, Konstantin Demin
set -ef

## shifty-nifty shell goodies :)

## do same thing as GitLab does for CI_COMMIT_REF_SLUG:
## 1. lowercase string
## 2. replace not allowed chars with '-' (squeezing repeats)
##    allowed chars are: `0-9`, `a-z` and '-'
## 3. remove leading and trailing '-' (if any)
## 4. truncate string up to 63 chars
## 5. remove trailing '-' (if any)
ref_slug() {
    printf '%s' "${1:?}" \
    | sed -Ez 's/^(.+)$/\L\1/;s/[^0-9a-z]+/-/g;s/^-//;s/-$//;s/^(.{1,63}).*$/\1/;s/-$//' \
    | tr -d '\0'
}

## normalize image tag
## performs like ref_slug() except:
## - symbols '_' and '.' are allowed too
## - truncate string up to 96 chars
## - squeeze symbol sequences:
##   - '-' has higher priority than surrounding (leading and trailing) symbols
##   - first symbol in sequence has higher priority than following symbols
## NB: implementation is rather demonstrative than effective
image_tag_norm() {
    printf '%s' "${1:?}" \
    | sed -Ez 's/^(.+)$/\L\1/;s/[^0-9a-z_.]+/-/g' \
    | sed -Ez 's/\.+/./g;s/_+/_/g;s/[_.]+-/-/g;s/-[_.]+/-/g;s/([_.])[_.]+/\1/g' \
    | sed -Ez 's/^[_.-]//;s/[_.-]$//;s/^(.{1,95}).*$/\1/;s/[_.-]$//' \
    | tr -d '\0'
}

## misc CI things
# CI_COMMIT_SHORT_SHA="${CI_COMMIT_SHA:0:8}"
CI_COMMIT_SHORT_SHA=$(printf '%s' "${CI_COMMIT_SHA}" | cut -c 1-8)
if [ -n "${CI_COMMIT_BRANCH}" ] ; then
    CI_COMMIT_REF_SLUG="${CI_COMMIT_BRANCH}"
fi
if [ -n "${CI_COMMIT_SOURCE_BRANCH}" ] ; then
    CI_COMMIT_REF_SLUG="${CI_COMMIT_SOURCE_BRANCH}"
fi
if [ -n "${CI_COMMIT_TAG}" ] ; then
    CI_COMMIT_REF_SLUG="${CI_COMMIT_TAG}"
fi
CI_COMMIT_REF_SLUG="$(image_tag_norm "${CI_COMMIT_REF_SLUG}")"

## image tag(s)
IMAGE_TAG="${CI_COMMIT_SHORT_SHA}-b${CI_PIPELINE_NUMBER}-${CI_COMMIT_REF_SLUG}"
EXTRA_TAGS=$(image_tag_norm "branch-${CI_COMMIT_BRANCH}")
if [ -n "${CI_COMMIT_TAG}" ] ; then
    IMAGE_TAG="${CI_COMMIT_SHORT_SHA}"
    EXTRA_TAGS="${CI_COMMIT_REF_SLUG}"
    ## TODO: think about "latest" tag: it should be error-prone for "backward tag push"
    # EXTRA_TAGS="${CI_COMMIT_REF_SLUG} latest"
else
    if [ -n "${CI_COMMIT_SOURCE_BRANCH}" ] ; then
        echo "Running on branch '${CI_COMMIT_SOURCE_BRANCH}'"
    else
        if [ "${CI_COMMIT_BRANCH}" != "${CI_REPO_DEFAULT_BRANCH}" ] ; then
            echo "Running on branch '${CI_COMMIT_BRANCH}'"
        else
            IMAGE_TAG="${CI_COMMIT_SHORT_SHA}"
        fi
    fi
fi
IMAGE_TAG=$(image_tag_norm "${IMAGE_TAG}")

export CI_COMMIT_SHORT_SHA CI_COMMIT_REF_SLUG IMAGE_TAG EXTRA_TAGS