#!/usr/bin/env bash
# Guard the trap in .gitea/workflows.
#
# Gitea uses .gitea/workflows IF IT EXISTS, and falls back to .github/workflows
# only when it does not. It never merges them. So a workflow that lives only in
# .github/ simply does not run on Gitea — no error, no run to click on. It
# looks exactly like a runner that has not picked the job up, so you wait, and
# waiting never fixes it.
#
# Workflows that must behave identically on both forges are therefore kept
# byte-identical in both roots, and this script fails when they drift or when
# one appears in only one root without a stated reason.
set -euo pipefail
cd "$(dirname "$0")/.."

# Workflows that are deliberately single-forge, and why.
declare -A only_on=(
  ["auto-merge.yml"]="github: it drives the GitHub merge API. Gitea merges the owner's green PRs itself."
  ["release.yml"]="both, but different: each publishes to the forge it runs on, and Gitea is where the update feed lives."
)

fail=0

for root in .github .gitea; do
  [ -d "$root/workflows" ] || { echo "$root/workflows is missing."; fail=1; }
done

for f in .github/workflows/*.yml .gitea/workflows/*.yml; do
  [ -e "$f" ] || continue
  name=$(basename "$f")
  gh=".github/workflows/$name"
  gt=".gitea/workflows/$name"

  case "${only_on[$name]:-}" in
    github:*)
      [ -f "$gt" ] && { echo "$name is marked GitHub-only but exists in .gitea/workflows too."; fail=1; }
      continue
      ;;
    both,*|"both, "*)
      # Present in both, intentionally different. Both copies must exist.
      { [ -f "$gh" ] && [ -f "$gt" ]; } \
        || { echo "$name is expected in both roots, but one copy is missing."; fail=1; }
      continue
      ;;
  esac

  if [ ! -f "$gh" ] || [ ! -f "$gt" ]; then
    echo "$name exists in only one workflow root and is not listed in ci/workflows-in-sync.sh."
    echo "  A workflow missing from .gitea/workflows does not run on Gitea, silently."
    fail=1
    continue
  fi

  if ! cmp -s "$gh" "$gt"; then
    echo "$name has drifted between the two roots:"
    diff -u "$gh" "$gt" || true
    fail=1
  fi
done

# Measured on Gitea 1.27.2: a workflow-level `concurrency:` block produced no
# run at all — not a failed one, not a cancelled one. It may have been fixed
# since, but the cost of keeping the rule is nil and the cost of rediscovering
# it is an afternoon of blaming the runner.
if grep -rn '^concurrency:' .gitea/workflows/ 2>/dev/null; then
  echo "A workflow-level concurrency: block can stop a Gitea workflow from running at all."
  fail=1
fi

# A workflow that does not parse produces no run — the same symptom as every
# other trap in this file. ci.yml cannot catch its own syntax error this way,
# but release.yml and compat.yml can be caught here rather than on the tag.
if python3 -c 'import yaml' 2>/dev/null; then
  for f in .github/workflows/*.yml .gitea/workflows/*.yml; do
    [ -e "$f" ] || continue
    python3 -c 'import sys,yaml; yaml.safe_load(open(sys.argv[1]))' "$f" \
      || { echo "$f is not valid YAML, so it will simply never run."; fail=1; }
  done
else
  echo "(PyYAML is not installed here, so the workflow files were not parsed.)"
fi

[ "$fail" = 0 ] || exit 1
echo "Workflows: in sync."