#!/bin/sh
# =============================================================================
# ZDDC shared build helpers — sourced by each tool's build.sh
#
# Usage in a tool build.sh:
#   root_dir=$(cd "$(dirname "$0")" && pwd)
#   . "$root_dir/../shared/build-lib.sh"
#
# Provides:
#   ensure_exists <path>          — abort with error if file missing
#   concat_files  <file ...>      — cat each relative path under $root_dir
#   build_timestamp               — ISO UTC timestamp string, set at source time;
#                                   used as build_label for dev builds
#   escape_js_close_tags <in> <out>
#                                 — copy <in> to <out> with all '</' rewritten as
#                                   '<\/' so the HTML parser cannot misread the
#                                   inlined JS as containing a closing </script>.
#                                   The JS engine treats \/ as a regular slash,
#                                   so runtime behaviour is unchanged.
#   compute_build_label <tool> [--release [<beta-or-version>]]
#                                 — sets globals: build_label, build_version,
#                                   is_release, is_red, channel.
#                                   See "Release args" below.
#   promote_release <tool>        — for stable cuts, copy the dist HTML into
#                                   the release-output bundle (default
#                                   $root_dir/../dist/release-output;
#                                   override $ZDDC_DEPLOY_RELEASES_DIR).
#                                   Writes the immutable per-version file
#                                   <tool>_v<X.Y.Z>.html plus the canonical
#                                   symlink <tool>.html pointing at it.
#                                   Tagging is centralized in the top-level
#                                   ./build (after the embedded commit).
#                                   Beta cuts produce NO public artifact —
#                                   they are an internal SHA snapshot for
#                                   the BMC dev chart pipeline; the
#                                   embedded/* regeneration + chore commit
#                                   in the top-level ./build is the actual
#                                   artifact (chart appVersion pins to that
#                                   SHA, Dockerfile fetches it from git).
#
# Release args:
#   <none>            dev build, tool/dist/ only, label
#                     "v<next-stable>-dev · <ts> · <sha>[-dirty]" (red).
#                     No release-output side-effect.
#   --release         stable cut, auto-bump patch from latest tag (or 0.0.1).
#                     Writes <tool>_v<X.Y.Z>.html + <tool>.html symlink;
#                     tagged later by ./build.
#   --release X.Y.Z   stable cut, explicit version.
#   --release beta    internal SHA snapshot for the BMC dev chart. Build
#                     label is "v<next-stable>-beta · <date> · <sha>";
#                     no public artifact, no tag. The top-level ./build
#                     regenerates zddc/internal/apps/embedded/ + commits.
#   --release <other> error.
# =============================================================================

# Abort if root_dir is not set by the caller
if [ -z "${root_dir:-}" ]; then
    echo "build-lib.sh: root_dir must be set before sourcing this file" >&2
    exit 1
fi

# NOTE: there's no Codeberg release-asset publication path anymore. All
# release artifacts (HTML tools + zddc-server binaries) materialize in
# dist/release-output/ via the lockstep ./build, then ./deploy rsyncs
# them to /srv/zddc/ on the deploy host. The deprecated zddc/release.sh
# is now a no-op guard that prints a redirection message.

# Fail hard on any missing source file
ensure_exists() {
    _path="$1"
    if [ ! -f "$_path" ]; then
        echo "error: missing file: $_path" >&2
        exit 1
    fi
}

# Concatenate files listed as positional args, each relative to root_dir
concat_files() {
    for _rel do
        ensure_exists "$root_dir/$_rel"
        cat "$root_dir/$_rel"
        printf '\n'
    done
}

# ISO UTC build timestamp — set once when this file is sourced
build_timestamp=$(date -u +"%Y-%m-%d %H:%M:%S")

# Read shared/favicon.svg, base64-encode it, and assemble a data: URI suitable
# for inlining into a <link rel="icon" type="image/svg+xml" href="..."> tag.
# Set once at source time so every tool's build.sh can pick it up via the
# $favicon_data_uri global. Editing shared/favicon.svg auto-propagates to all
# tools on the next build.
_favicon_path="$root_dir/../shared/favicon.svg"
if [ -f "$_favicon_path" ]; then
    favicon_data_uri="data:image/svg+xml;base64,$(base64 -w 0 "$_favicon_path")"
else
    favicon_data_uri=""
fi

# Rewrite '</script' (case-insensitive) in JS as '<\/script' so the HTML parser
# cannot mistake string contents for a closing </script> tag. Per the HTML5 spec
# only </script terminates a <script> block — other tags like </div> are safe
# inside a script's text content. Narrowly targeting </script avoids corrupting
# regex literals like /</g whose trailing letter is a flag, not a tag name.
# The JS engine treats '\/' the same as '/' inside a string, so behaviour is
# unchanged. See ARCHITECTURE.md "HTML Embedding Safety".
escape_js_close_tags() {
    sed 's#</\([sS][cC][rR][iI][pP][tT]\)#<\\/\1#g' "$1" > "$2"
}

# Validate that $1 is a strict X.Y.Z numeric version, where each component
# is a non-empty numeric string. Exits with an error if not.
_validate_semver() {
    _v="$1"
    _bad() {
        echo "error: invalid release argument: '$_v' (expected: beta, or X.Y.Z stable version)" >&2
        exit 1
    }
    _v1="${_v%%.*}"
    _rest="${_v#*.}"
    [ "$_rest" = "$_v" ] && _bad
    _v2="${_rest%%.*}"
    _v3="${_rest#*.}"
    { [ "$_v3" = "$_rest" ] || [ "$_v3" != "${_v3%.*}" ]; } && _bad
    case "$_v1" in '' | *[!0-9]*) _bad ;; esac
    case "$_v2" in '' | *[!0-9]*) _bad ;; esac
    case "$_v3" in '' | *[!0-9]*) _bad ;; esac
}

# Walk backwards from HEAD until a non-auto-commit is found, return the
# resolved git ref (e.g. "HEAD~2"). Auto-commits are recognised by their
# canonical commit-message prefixes:
#
#   - "chore(embedded): cut v<X.Y.Z>-beta"   (beta auto-commit, build:993)
#   - "release: v<X.Y.Z> lockstep"           (stable auto-commit, build:986)
#
# Used by the build-label helpers to derive a stable identifier (short
# SHA, three-word slug) from the underlying source state. The source
# ref is invariant across the auto-commit step (HEAD shifts when
# embedded bytes change), so a re-run on the same source state produces
# the same identifiers and no spurious commit.
#
# Defensive cap: stops walking after 32 commits and returns whatever
# ref was reached.
_source_commit_ref() {
    _i=0
    _ref="HEAD"
    while [ "$_i" -lt 32 ]; do
        _msg=$(git -C "$root_dir" log -1 --format=%s "$_ref" 2>/dev/null || echo "")
        case "$_msg" in
            "chore(embedded): cut v"* | "release: v"*" lockstep")
                _ref="${_ref}~1"
                _i=$((_i + 1))
                continue
                ;;
        esac
        break
    done
    echo "$_ref"
}

# Short SHA of the underlying source commit (skipping past embedded
# auto-commits — see _source_commit_ref). Same source state → same SHA
# even after a `chore(embedded): cut …` commit has landed on top.
_source_commit_short_sha() {
    _ref=$(_source_commit_ref)
    git -C "$root_dir" rev-parse --short=7 "$_ref" 2>/dev/null || echo "unknown"
}

# Compute build label and channel. Reads positional args:
#   compute_build_label <tool_name> [--release [<beta-or-version>]]
# Sets global variables:
#   build_label    — text rendered into the page's {{BUILD_LABEL}} slot
#   build_version  — bare semver string (stable releases only)
#   is_release     — "1" for any --release invocation, else "0"
#   is_red         — "1" if the label should render red+bold (dev/beta), else "0"
#   channel        — "stable" / "beta" / "dev"
#
# Versioning: pre-release semver. The next-stable target is computed from
# the latest clean tool-vX.Y.Z tag (patch-bump). Plain dev builds and
# `--release beta` carry the next-stable target as a pre-release suffix
# in the on-page label so users can see which stable the snapshot is
# working toward. Stable releases write a clean vX.Y.Z label and tag.
#
# HTML tools do NOT tag beta cuts — beta produces no public artifact
# (the chart pins by SHA via appVersion). Plain dev builds and beta
# cuts share the same on-page label format (full UTC timestamp + short
# source SHA). A plain dev build may carry a "-dirty" SHA suffix when
# the working tree has uncommitted changes; release cuts don't.
compute_build_label() {
    _tool="$1"
    _flag="${2:-}"
    _arg="${3:-}"

    is_release=0
    is_red=1
    channel=""
    build_version=""

    # Compute the next-stable target once for label inclusion.
    _next_stable=$(_next_stable_for_tool "$_tool")

    if [ "$_flag" != "--release" ]; then
        # Plain builds are dev iteration — tool/dist/ only, no release
        # output. The label includes the next-stable target so a developer
        # opening the local dist file can see which version-in-progress
        # they're looking at. Full timestamp + dirty marker distinguish
        # iterative dev builds from formal cuts.
        _sha=$(git -C "$root_dir" rev-parse --short=7 HEAD 2>/dev/null || echo "unknown")
        if ! git -C "$root_dir" diff --quiet HEAD 2>/dev/null; then
            _sha="${_sha}-dirty"
        fi
        channel="dev"
        build_label="v${_next_stable}-dev · ${build_timestamp} · ${_sha}"
        _emit_build_label_sidecar "$_tool"
        return 0
    fi

    is_release=1

    case "$_arg" in
        beta)
            channel="beta"
            # Internal SHA snapshot for the BMC dev chart. The chart's
            # appVersion gets set to "<next>-beta-<sha>" and the
            # Dockerfile parses the suffix to fetch this SHA from git.
            # _source_commit_short_sha walks past any `chore(embedded):
            # cut …` auto-commit at HEAD so a re-cut on unchanged
            # source produces the same SHA.
            _sha=$(_source_commit_short_sha)
            build_label="v${_next_stable}-beta · ${build_timestamp} · ${_sha}"
            _emit_build_label_sidecar "$_tool"
            return 0
            ;;
        '')
            # Stable cut, auto-bump patch.
            build_version="$_next_stable"
            ;;
        *)
            _validate_semver "$_arg"
            build_version="$_arg"
            ;;
    esac

    channel="stable"
    is_red=0
    build_label="v${build_version}"
    _emit_build_label_sidecar "$_tool"
}

# Write the resolved build label to a sidecar file the top-level build.sh
# reads to assemble zddc/internal/apps/embedded/versions.txt. No-op when
# BUILD_LABELS_DIR is not set in the env (tools built standalone).
_emit_build_label_sidecar() {
    if [ -z "${BUILD_LABELS_DIR:-}" ]; then
        return 0
    fi
    mkdir -p "$BUILD_LABELS_DIR"
    printf '%s\n' "$build_label" > "$BUILD_LABELS_DIR/$1.label"
}

# Tools that participate in the lockstep release. Source of truth — used
# by helpers that enumerate "all release artifacts" (matrix render,
# coordinated next-stable).
ZDDC_RELEASE_TOOLS="archive transmittal classifier landing form tables browse zddc-server"

# Compute the next-stable target for a single tool — patch-bump of its own
# latest <tool>-vX.Y.Z tag. Used by compute_build_label so a tool's
# on-page label reads against its own history (e.g. a beta cut for a
# tool that's been quiet still labels itself targeting that tool's next
# stable, even when the lockstep convention is in force).
_next_stable_for_tool() {
    _t="$1"
    _latest=$(git -C "$root_dir" tag --list "${_t}-v*" 2>/dev/null \
              | grep -E "^${_t}-v[0-9]+\.[0-9]+\.[0-9]+\$" \
              | sed "s|^${_t}-v||" \
              | sort -V \
              | tail -1)
    [ -n "$_latest" ] || _latest="0.0.0"
    _major="${_latest%%.*}"
    _rest="${_latest#*.}"
    _minor="${_rest%%.*}"
    _patch="${_rest#*.}"
    echo "${_major}.${_minor}.$((_patch + 1))"
}

# Compute the coordinated next-stable target across every release artifact
# (5 HTML tools + zddc-server). Used by the top-level build.sh on
# `--release` (no explicit version) to enforce lockstep — every tool cuts
# at the same version even if it hasn't changed. Picks max(latest tag
# across all tools) + patch bump, so a tool at v0.0.2 jumps straight to
# wherever the leader is + 1 the first time the lockstep rule fires.
_coordinated_next_stable() {
    _max="0.0.0"
    for _t in $ZDDC_RELEASE_TOOLS; do
        _latest=$(git -C "$root_dir" tag --list "${_t}-v*" 2>/dev/null \
                  | grep -E "^${_t}-v[0-9]+\.[0-9]+\.[0-9]+\$" \
                  | sed "s|^${_t}-v||" \
                  | sort -V \
                  | tail -1)
        [ -n "$_latest" ] || continue
        # sort -V picks the larger of two semvers
        _max=$(printf '%s\n%s\n' "$_max" "$_latest" | sort -V | tail -1)
    done
    _major="${_max%%.*}"
    _rest="${_max#*.}"
    _minor="${_rest%%.*}"
    _patch="${_rest#*.}"
    echo "${_major}.${_minor}.$((_patch + 1))"
}

# Promote a built dist file to the release-output bundle. Reads from caller
# scope: $channel ("stable" / "beta"), $build_version (stable only),
# $output_html, $root_dir. Bundle path resolves from $ZDDC_DEPLOY_RELEASES_DIR
# (default $root_dir/../dist/release-output).
#
# Stable cuts:
#   1. Copy dist HTML → <bundle>/<tool>_v<X.Y.Z>.html (immutable).
#   2. Refresh canonical symlink: <bundle>/<tool>.html → the new versioned file.
#   3. Tag the commit <tool>-v<X.Y.Z> (centralized in the top-level ./build).
#
# Beta cuts:
#   No public artifact. The chart's Dockerfile fetches the source at the
#   SHA pinned in chart appVersion and compiles its own binary; the
#   embedded/* regeneration + chore commit in the top-level ./build is
#   the actual snapshot.
#
# Plain dev builds (no --release): never call promote_release.
promote_release() {
    _tool="$1"
    # The top-level `./build` exports $ZDDC_DEPLOY_RELEASES_DIR pointing
    # at $SCRIPT_DIR/dist/release-output. Single-tool standalone
    # invocations fall back to the same default — no inheritance from a
    # parent build run.
    _releases_dir="${ZDDC_DEPLOY_RELEASES_DIR:-$root_dir/../dist/release-output}"
    mkdir -p "$_releases_dir"

    if [ ! -d "$_releases_dir" ]; then
        echo "promote_release: $_releases_dir not found" >&2
        return 1
    fi

    case "$channel" in
        stable)
            if [ -z "$build_version" ]; then
                echo "promote_release: stable channel but no build_version" >&2
                return 1
            fi
            # Lockstep: every release cut writes per-version files for
            # every tool, even when a tool's source hasn't changed since
            # its last tag. The bytes are identical (build is deterministic
            # at the same source), so the overwrite is a no-op on disk;
            # but the canonical symlink <tool>.html advances to the new
            # version, which is the actual goal.
            _promote_stable "$_tool" "$build_version" "$_releases_dir"
            ;;
        beta)
            # Internal SHA snapshot for the BMC dev chart. No public
            # artifact: the chart fetches the source at the SHA via git,
            # the embedded/* regeneration + chore commit (in the top-
            # level ./build) IS the artifact.
            echo "  ${_tool}: beta is internal (no public artifact)"
            ;;
        *)
            echo "promote_release: unknown channel '$channel'" >&2
            return 1
            ;;
    esac
}

# Stable cut: per-version immutable file + canonical symlink. Tagging is
# centralized in the top-level ./build (it commits embedded artifacts
# FIRST, then tags at the new commit — see "Release commit + tag" block
# at the bottom of the script). _promote_stable historically created
# tags itself, but that placed them on the source-side commit before
# embedded files were folded in, leaving prod binaries with stale bytes
# baked in.
_promote_stable() {
    _t="$1"
    _ver="$2"
    _rdir="$3"

    _versioned="${_t}_v${_ver}.html"
    _canonical="${_t}.html"

    cp "$output_html" "$_rdir/$_versioned"
    echo "Wrote $_rdir/$_versioned"

    ln -sfn "$_versioned" "$_rdir/$_canonical"
    echo "  $_canonical → $_versioned"

    # Companion .sig symlink so `curl <canonical>.sig` resolves. The
    # actual .sig file is written by sign_release_artifacts; this
    # symlink points there.
    ln -sfn "${_versioned}.sig" "$_rdir/${_canonical}.sig"

    # Pre-flight check only: if the tag already exists pointing at a
    # commit that is NOT an ancestor of HEAD, the operator needs to
    # resolve manually before this cut can complete cleanly.
    _tag="${_t}-v${_ver}"
    if git -C "$root_dir" rev-parse -q --verify "refs/tags/$_tag" >/dev/null; then
        _existing=$(git -C "$root_dir" rev-list -n 1 "$_tag")
        _head=$(git -C "$root_dir" rev-parse HEAD)
        if [ "$_existing" != "$_head" ] \
           && ! git -C "$root_dir" merge-base --is-ancestor "$_existing" "$_head"; then
            echo "promote_release: tag $_tag exists at $_existing which is not in HEAD's history" >&2
            echo "                 manual intervention required before re-running" >&2
            return 1
        fi
    fi

    echo "Released ${_t} v${_ver} (stable; tagging deferred to top-level build)"
}

# Platforms zddc-server is cross-compiled for. The first three are
# extension-less (Linux/macOS); Windows gets .exe. The build always emits
# all four; the matrix cell's stub page links each by its <platform> tag.
ZDDC_SERVER_PLATFORMS="linux-amd64 darwin-amd64 darwin-arm64 windows-amd64"

# Display label for the stub-page download list. Keeps the binary-asset
# names canonical even if we later add e.g. linux-arm64.
_zddc_server_platform_label() {
    case "$1" in
        linux-amd64)   echo "Linux (x86_64)" ;;
        darwin-amd64)  echo "macOS (Intel)" ;;
        darwin-arm64)  echo "macOS (Apple Silicon)" ;;
        windows-amd64) echo "Windows (x86_64)" ;;
        *)             echo "$1" ;;
    esac
}

# Resolve a zddc-server binary's filename for one (slug, platform).
# Returns the bare name (no path); ".exe" suffix on windows. Empty slug
# means the canonical "current stable" symlink (zddc-server_<plat>);
# non-empty slug is a per-version asset (zddc-server_v<X.Y.Z>_<plat>).
_zddc_server_binary_name() {
    _slug="$1"
    _plat="$2"
    _suffix=""
    case "$_plat" in *windows*) _suffix=".exe" ;; esac
    if [ -z "$_slug" ]; then
        printf 'zddc-server_%s%s' "$_plat" "$_suffix"
    else
        printf 'zddc-server_%s_%s%s' "$_slug" "$_plat" "$_suffix"
    fi
}

# Write the small HTML index page that becomes the entry point for a
# zddc-server release. Lists each platform binary with a download link.
# $1 — release directory (absolute)
# $2 — slug ("" for canonical "current stable", or "v0.0.8" per-version)
# $3 — display label (e.g. "current stable", "v0.0.8")
write_zddc_server_stub() {
    _rdir="$1"
    _slug="$2"
    _label="$3"
    if [ -z "$_slug" ]; then
        _out="$_rdir/zddc-server.html"
    else
        _out="$_rdir/zddc-server_${_slug}.html"
    fi

    {
        cat <<HEAD
<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>zddc-server ${_label} — ZDDC</title>
  <link rel="stylesheet" href="../css/style.css">
  <style>
    .dl-table { width: 100%; border-collapse: collapse; margin: 1rem 0; }
    .dl-table th, .dl-table td { text-align: left; padding: 0.5rem 0.75rem; border-bottom: 1px solid var(--color-border); }
    .dl-table a { color: var(--color-primary); text-decoration: none; font-family: ui-monospace, SFMono-Regular, Menlo, monospace; font-size: 0.9rem; }
    .dl-table a:hover { text-decoration: underline; }
    .breadcrumb { color: var(--color-text-muted); margin-bottom: 1rem; font-size: 0.9rem; }
    .breadcrumb a { color: var(--color-text-muted); }
  </style>
</head>
<body>
  <main class="container" style="max-width: 720px; margin: 2rem auto;">
    <p class="breadcrumb"><a href="/">home</a> &nbsp;/&nbsp; <a href="index.html">releases</a> &nbsp;/&nbsp; zddc-server ${_label}</p>
    <h1>zddc-server &mdash; ${_label}</h1>
    <p>Cross-compiled binaries. Download for your platform, mark executable, and run with <code>ZDDC_ROOT=/path/to/archive ./zddc-server</code>.</p>
    <table class="dl-table">
      <thead><tr><th>Platform</th><th>Download</th></tr></thead>
      <tbody>
HEAD
        for _plat in $ZDDC_SERVER_PLATFORMS; do
            _bin=$(_zddc_server_binary_name "$_slug" "$_plat")
            _plabel=$(_zddc_server_platform_label "$_plat")
            printf '        <tr><td>%s</td><td><a href="%s">%s</a></td></tr>\n' "$_plabel" "$_bin" "$_bin"
        done
        cat <<'TAIL'
      </tbody>
    </table>
    <p style="font-size: 0.9rem; color: var(--color-text-muted);">Need a different platform? Build from source: <code>(cd zddc &amp;&amp; go build -o zddc-server ./cmd/zddc-server)</code> from the repo at the matching tag.</p>
  </main>
</body>
</html>
TAIL
    } > "$_out"
}

# Refresh every zddc-server stub page based on what's currently in the
# release-output bundle: one per-version stub per zddc-server_v*_*
# binary set, plus a canonical zddc-server.html if the latest-stable
# symlinks are in place. Indexed off linux-amd64 since all four
# platforms ship in lockstep.
#
# $1 — releases dir (absolute)
write_zddc_server_stubs_all() {
    _rdir="$1"

    # Per-version stubs (immutable).
    for _bin in "$_rdir"/zddc-server_v*_linux-amd64; do
        [ -e "$_bin" ] || continue
        _name=$(basename "$_bin")
        _slug=$(echo "$_name" | sed -E 's/^zddc-server_(v[^_]+)_linux-amd64$/\1/')
        case "$_slug" in
            v*.*.*) write_zddc_server_stub "$_rdir" "$_slug" "$_slug" ;;
        esac
    done

    # Canonical stub (follows the latest-stable symlink). Probes the
    # linux-amd64 canonical name; if it exists, the platform symlinks
    # are in place and we can write the entry page.
    if [ -e "$_rdir/zddc-server_linux-amd64" ]; then
        write_zddc_server_stub "$_rdir" "" "current stable"
    fi
}

# Promote a freshly-cross-compiled set of zddc-server binaries to the
# release-output bundle. Called by the top-level ./build on a stable
# release cut. Beta cuts produce no public artifact (the chart's
# Dockerfile compiles from source at the SHA pinned in appVersion).
#
# $1 — channel ("stable" | "beta")
# $2 — version (X.Y.Z; required for stable; ignored for beta)
# $3 — releases dir (absolute)
# $4 — dist dir holding cross-compiled binaries (absolute)
promote_zddc_server() {
    _ch="$1"
    _ver="$2"
    _rdir="$3"
    _dist="$4"

    # Verify all four binaries exist before doing anything destructive.
    for _plat in $ZDDC_SERVER_PLATFORMS; do
        _suffix=""
        case "$_plat" in *windows*) _suffix=".exe" ;; esac
        _src="$_dist/zddc-server-${_plat}${_suffix}"
        if [ ! -f "$_src" ]; then
            echo "promote_zddc_server: missing source binary $_src" >&2
            return 1
        fi
    done

    case "$_ch" in
        stable)
            if [ -z "$_ver" ]; then
                echo "promote_zddc_server: stable cut requires version" >&2
                return 1
            fi

            # Per-version immutable + canonical per-platform symlink.
            for _plat in $ZDDC_SERVER_PLATFORMS; do
                _suffix=""
                case "$_plat" in *windows*) _suffix=".exe" ;; esac
                _src="$_dist/zddc-server-${_plat}${_suffix}"
                _versioned="zddc-server_v${_ver}_${_plat}${_suffix}"
                _canonical="zddc-server_${_plat}${_suffix}"
                cp "$_src" "$_rdir/$_versioned"
                echo "Wrote $_rdir/$_versioned"
                ln -sfn "$_versioned" "$_rdir/$_canonical"
                echo "  $_canonical → $_versioned"
                # Companion .sig symlink — see _promote_stable for the
                # same pattern.
                ln -sfn "${_versioned}.sig" "$_rdir/${_canonical}.sig"
            done

            # Pre-flight tag check only — actual tagging happens in the
            # top-level ./build after embedded artifacts are committed.
            # See _promote_stable for the same rationale.
            _tag="zddc-server-v${_ver}"
            if git -C "$root_dir" rev-parse -q --verify "refs/tags/$_tag" >/dev/null; then
                _existing=$(git -C "$root_dir" rev-list -n 1 "$_tag")
                _head=$(git -C "$root_dir" rev-parse HEAD)
                if [ "$_existing" != "$_head" ] \
                   && ! git -C "$root_dir" merge-base --is-ancestor "$_existing" "$_head"; then
                    echo "promote_zddc_server: tag $_tag exists at $_existing which is not in HEAD's history" >&2
                    echo "                     manual intervention required before re-running" >&2
                    return 1
                fi
            fi
            echo "Released zddc-server v${_ver} (stable; tagging deferred to top-level build)"
            ;;
        beta)
            # Internal SHA snapshot — the chart's Dockerfile fetches the
            # source at that SHA and compiles its own binary. No public
            # binary is published.
            echo "  zddc-server: beta is internal (no public artifact)"
            ;;
        *)
            echo "promote_zddc_server: unknown channel '$_ch'" >&2
            return 1
            ;;
    esac

    # Refresh stub pages (per-version + canonical).
    write_zddc_server_stubs_all "$_rdir"
}
