#!/usr/bin/env zsh

set -eu

for cmd in git sops openssl; do
  if ! command -v "${cmd}" >/dev/null 2>&1; then
    echo "pre-commit: required command missing: ${cmd}" >&2
    exit 1
  fi
done

if [ -z "${SOPS_SYNC_HMAC_KEY:-}" ]; then
  echo "pre-commit: SOPS_SYNC_HMAC_KEY is required" >&2
  exit 1
fi

repo_root=$(git rev-parse --show-toplevel)
regex_script="${repo_root}/scripts/lib/sops-path-regexes"
lib_script="${repo_root}/scripts/lib/sops-sync-lib"

if [ ! -x "${regex_script}" ]; then
  echo "pre-commit: missing helper ${regex_script}" >&2
  exit 1
fi

if [ ! -f "${lib_script}" ]; then
  echo "pre-commit: missing helper ${lib_script}" >&2
  exit 1
fi

. "${lib_script}"

regexes=("${(@f)$("${regex_script}")}")
typeset -A candidates

while IFS= read -r staged_path; do
  [ -n "${staged_path}" ] || continue

  candidate_enc=""
  if [[ "${staged_path}" == *.enc.yaml ]]; then
    candidate_enc="${staged_path}"
  elif [[ "${staged_path}" == *.yaml ]]; then
    if git ls-files --error-unmatch -- "${staged_path}" >/dev/null 2>&1; then
      continue
    fi
    candidate_enc=$(plain_to_enc "${staged_path}") || continue
  fi

  [ -n "${candidate_enc}" ] || continue
  if matches_any_rule "${candidate_enc}" "${regexes[@]}"; then
    candidates["${candidate_enc}"]=1
  fi
done < <(git diff --cached --name-only --diff-filter=ACMR)

for enc_path in "${(@k)candidates}"; do
  plain_path=$(enc_to_plain "${enc_path}") || continue
  sidecar_path=$(hmac_sidecar_for_enc "${enc_path}")

  if [ ! -f "${plain_path}" ]; then
    continue
  fi

  if has_unstaged_changes "${plain_path}"; then
    echo "pre-commit: plaintext file has unstaged changes: ${plain_path}" >&2
    echo "pre-commit: stage or revert the plaintext change before committing" >&2
    exit 1
  fi

  current_hmac=$(compute_hmac_for_file "${plain_path}")
  tracked_hmac=""
  if [ -f "${sidecar_path}" ]; then
    tracked_hmac=$(read_sidecar "${sidecar_path}" || true)
  fi

  if [ "${current_hmac}" = "${tracked_hmac}" ] && [ -f "${enc_path}" ]; then
    continue
  fi

  encrypt_plain_to_enc "${plain_path}" "${enc_path}"
  write_sidecar "${sidecar_path}" "${current_hmac}"
  git add "${enc_path}" "${sidecar_path}"
done

for enc_path in "${(@k)candidates}"; do
  sidecar_path=$(hmac_sidecar_for_enc "${enc_path}")

  if ! git cat-file -e ":${enc_path}" 2>/dev/null; then
    echo "pre-commit: staged encrypted file missing: ${enc_path}" >&2
    exit 1
  fi

  if ! git cat-file -e ":${sidecar_path}" 2>/dev/null; then
    echo "pre-commit: staged sync sidecar missing: ${sidecar_path}" >&2
    exit 1
  fi

  tmp_enc=$(mktemp)
  trap 'rm -f "${tmp_enc}"' EXIT INT TERM
  git show ":${enc_path}" > "${tmp_enc}"

  staged_hmac=$(git show ":${sidecar_path}" | tr -d '\r\n')
  computed_hmac=$(decrypt_enc_to_plain "${tmp_enc}" | compute_hmac_for_stdin)

  rm -f "${tmp_enc}"
  trap - EXIT INT TERM

  if [ "${computed_hmac}" != "${staged_hmac}" ]; then
    echo "pre-commit: staged encrypted file and sidecar are out of sync: ${enc_path}" >&2
    exit 1
  fi
done