#!/usr/bin/env bash
# Emit per-service + aggregate change flags for the CI / build workflows.
#
# Reads:
#   BASE_SHA — diff base. Empty / unreachable / diff-failure → emit everything as true.
#   HEAD_SHA — diff target. Defaults to HEAD.
#
# Writes key=value lines to $GITHUB_OUTPUT (defaults to /dev/stdout for local runs).
#
# ROBUSTNESS CONTRACT: this script must ALWAYS emit a full set of outputs. A
# missing/empty output makes the job's `outputs:` mapping evaluate to a Go format
# error (`%!t(string=)`) which fails detect-changes AND every job that `needs` it
# (cascade). So we do NOT use `set -e` (an aborting git/grep must not kill the
# script before it emits), we treat any base/diff failure as "rebuild all", and an
# EXIT trap emits rebuild-all + forces exit 0 if we ever exit early/unexpectedly.
#
# Keys emitted:
#   admin, backend, sdk, portal, tts, crawler, dsms_gateway, dsms_node
#   any_python, any_node, any

set -uo pipefail

BASE_SHA="${BASE_SHA:-}"
HEAD_SHA="${HEAD_SHA:-HEAD}"
OUT="${GITHUB_OUTPUT:-/dev/stdout}"

ALL_KEYS=(admin backend sdk portal tts crawler dsms_gateway dsms_node any_python any_node any)

emit() {
  echo "$1=$2" >> "$OUT"
}

emit_all_true() {
  reason=$1
  echo "→ rebuild all: $reason"
  for k in "${ALL_KEYS[@]}"; do
    emit "$k" true
  done
}

# Safety net: never let the job end with undefined outputs. If we exit before
# DONE=1 (any error / early termination), emit rebuild-all and exit 0 so the
# step still succeeds — rebuild-all is the safe over-approximation.
DONE=0
trap '[ "$DONE" = 1 ] || emit_all_true "safety-net (unexpected exit)"; exit 0' EXIT

if [ -z "$BASE_SHA" ]; then
  emit_all_true "no BASE_SHA provided"
  DONE=1; exit 0
fi

if ! git rev-parse --verify "${BASE_SHA}^{commit}" >/dev/null 2>&1; then
  emit_all_true "BASE_SHA ${BASE_SHA} unreachable"
  DONE=1; exit 0
fi

if ! changed=$(git diff --name-only "$BASE_SHA" "$HEAD_SHA" 2>/dev/null); then
  emit_all_true "git diff against ${BASE_SHA} failed"
  DONE=1; exit 0
fi

echo "Changed files since ${BASE_SHA}:"
echo "${changed:-(none)}"
echo "---"

check() {
  key=$1
  path=$2
  if echo "$changed" | grep -q "^${path}/"; then
    emit "$key" true
    echo "  ${key} (${path}/): true"
  else
    emit "$key" false
    echo "  ${key} (${path}/): false"
  fi
}

check admin         admin-compliance
check backend       backend-compliance
check sdk           ai-compliance-sdk
check portal        developer-portal
check tts           compliance-tts-service
check crawler       document-crawler
check dsms_gateway  dsms-gateway
check dsms_node     dsms-node

# Aggregate flags
if echo "$changed" | grep -qE "^(backend-compliance|document-crawler|dsms-gateway|compliance-tts-service)/"; then
  emit any_python true
  echo "  any_python: true"
else
  emit any_python false
  echo "  any_python: false"
fi

if echo "$changed" | grep -qE "^(admin-compliance|developer-portal)/"; then
  emit any_node true
  echo "  any_node: true"
else
  emit any_node false
  echo "  any_node: false"
fi

if [ -n "$changed" ]; then
  emit any true
  echo "  any: true"
else
  emit any false
  echo "  any: false"
fi

DONE=1