#!/usr/bin/env bash
#
# CI's last act.
#
# Resolves the digest each service's commit-SHA tag points at, writes those digests into
# deploy/chart/values.yaml, and commits. That commit is the deploy: ArgoCD is watching
# master and picks it up. This script does not, and must not, talk to the cluster.
#
# Called by .gitea/workflows/ci.yaml on master only. Runnable by hand for a re-bump:
#   REGISTRY=gitea.oci-oci.duckdns.org IMAGE_NS=gitea_admin IMAGE_TAG=<sha> ./scripts/bump-digests.sh
#
# -e   a failed inspect must not lead to committing a stale digest
# -u   an unset REGISTRY would silently resolve the wrong image
# -o pipefail   the digest comes out of a pipe; without this, a failing inspect that pipes
#               into a successful grep exits 0 and writes garbage
set -euo pipefail

: "${REGISTRY:?REGISTRY must be set}"
: "${IMAGE_NS:?IMAGE_NS must be set}"
: "${IMAGE_TAG:?IMAGE_TAG must be set (the commit sha the images were built from)}"

SERVICES=(api worker reconciler)
CHART_VALUES="deploy/chart/values.yaml"

WORKDIR="$(mktemp -d)"
cleanup() {
    rm -rf "${WORKDIR}"
}
trap cleanup EXIT

# yq as a checksum-pinned binary, NOT `docker run -v "$PWD:/work"`.
#
# The container form cannot see the checkout on the Gitea runner: the -v source path is
# resolved by the dind sidecar's daemon, not by the job container, so yq reported
# "stat deploy/chart/values.yaml: no such file or directory" for a file that plainly
# exists. The same boundary silently broke helm and gitleaks.
#
# Not python+pyyaml: a yaml round-trip strips every comment in values.yaml, and those
# comments are the only thing explaining why the digests are there. yq edits in place.
YQ_VERSION="4.44.6"
YQ_SHA256="9477ac3cc447b6c083986129e35af8122eb2b938fe55c9c3e40436fb966e5813"

ensure_yq() {
    if command -v yq >/dev/null 2>&1; then
        return
    fi
    local arch
    case "$(uname -m)" in
        aarch64|arm64) arch=arm64 ;;
        x86_64)        arch=amd64 ;;
        *) echo "!! unsupported arch $(uname -m)" >&2; exit 1 ;;
    esac
    curl -fsSL -o "${WORKDIR}/yq" \
        "https://github.com/mikefarah/yq/releases/download/v${YQ_VERSION}/yq_linux_${arch}"
    # Only the arm64 digest is pinned; this runner is Ampere. On another arch the download
    # is still version-pinned, and the mismatch is reported rather than silently accepted.
    if [ "${arch}" = "arm64" ]; then
        echo "${YQ_SHA256}  ${WORKDIR}/yq" | sha256sum -c -
    else
        echo "warning: no pinned checksum for ${arch}; version-pinned only" >&2
    fi
    chmod +x "${WORKDIR}/yq"
    PATH="${WORKDIR}:${PATH}"
    export PATH
}

ensure_yq

echo "==> resolving digests for tag ${IMAGE_TAG}"
for svc in "${SERVICES[@]}"; do
    image="${REGISTRY}/${IMAGE_NS}/svcforge-${svc}"
    digest="$(docker buildx imagetools inspect "${image}:${IMAGE_TAG}" --format '{{.Manifest.Digest}}')"

    # Defence against a silently empty inspect. Without this, `yq` would happily write an
    # empty digest and the chart's own guard would fail the release later, further from
    # the cause.
    if [[ ! "${digest}" =~ ^sha256:[0-9a-f]{64}$ ]]; then
        echo "!! ${svc}: refusing to write a non-digest: '${digest}'" >&2
        exit 1
    fi

    echo "    ${svc} -> ${digest}"
    echo "${digest}" > "${WORKDIR}/${svc}.digest"
done

echo "==> writing ${CHART_VALUES}"
for svc in "${SERVICES[@]}"; do
    digest="$(cat "${WORKDIR}/${svc}.digest")"
    # env(...) rather than string interpolation: a digest is attacker-controlled only in
    # theory, but yq expression injection is not a thing worth leaving open.
    DIGEST="${digest}" yq -i ".image.${svc}.digest = strenv(DIGEST)" "${CHART_VALUES}"
done

if git diff --quiet -- "${CHART_VALUES}"; then
    echo "==> no digest changed; nothing to commit"
    exit 0
fi

echo "==> committing"
git config user.name "svcforge-ci"
git config user.email "ci@svcforge.invalid"
git add "${CHART_VALUES}"
git commit -m "ci: bump image digests to ${IMAGE_TAG}

Built and scanned by ${IMAGE_TAG}. ArgoCD syncs from this commit.

[skip ci]"
git push origin HEAD:master

echo "==> done. ArgoCD owns it from here."