#!/usr/bin/env bash
# =============================================================================
# lib/git-crypt.sh
# git-crypt lifecycle management (init, export, verify, rotate).
# =============================================================================

gcrypt_init() {
  git-crypt init
  success "git-crypt initialized in $(pwd)"
}

gcrypt_export_key() {
  local genome_name="$1"
  local key_path="${KEYS_DIR}/${genome_name}.key"

  mkdir -p "${KEYS_DIR}"
  git-crypt export-key "$key_path"
  success "Symmetric key exported to: $key_path"
  warn "SECURITY ALERT: Move this key to Vaultwarden and delete it from disk immediately."
}

gcrypt_verify() {
  local genome_name="$1"

  info "Verifying git-crypt configuration for ${genome_name}..."

  # `git-crypt status` reports the CONFIGURED status (from `.gitattributes`), not the
  # lock/unlock status of the working tree. Encrypted lines have their labels right-aligned
  # (with leading whitespace), so you CANNOT anchor on `^encrypted`.
  # We filter by private/ and distinguish “encrypted” from “not encrypted” without
  # relying on exact spacing.
  local status_out encrypted_count not_encrypted_count
  status_out=$(git-crypt status 2>/dev/null || true)
  encrypted_count=$(printf '%s\n' "$status_out"     | grep 'private/' | grep -cE '^[[:space:]]*encrypted:' || true)
  not_encrypted_count=$(printf '%s\n' "$status_out" | grep 'private/' | grep -cE '^not encrypted:'        || true)

  if [[ "$encrypted_count" -gt 0 ]]; then
    success "Encryption configured: ${encrypted_count} private file(s) under git-crypt."
    if [[ "$not_encrypted_count" -gt 0 ]]; then
      warn "${not_encrypted_count} file(s) under private/ are NOT covered by the git-crypt filter — check .gitattributes (leak risk)."
    fi
  elif [[ "$not_encrypted_count" -gt 0 ]]; then
    warn "private/ files exist but none are covered by the git-crypt filter — check the .gitattributes filter (leak risk)."
  else
    info "No private/ files present yet — nothing to verify."
  fi
}

# ---------------------------------------------------------------------------
# gcrypt_rotate_key <genome_name>
# Rotates the git-crypt symmetric key for the current genome directory.
#
# WHAT THIS DOES:
#   1. Unlocks the repo with the existing key (working tree is decrypted).
#   2. Removes the old key material from .git/git-crypt/keys/.
#   3. Runs git-crypt init to generate a new symmetric key.
#   4. Stages and commits private files — they are re-encrypted with the new key.
#   5. Exports the new key to KEYS_DIR for Vaultwarden upload.
#
# WHAT THIS DOES NOT DO (limitation):
#   Git history still contains blobs encrypted with the OLD key. Anyone who
#   has the old key and access to the git history can still decrypt those blobs.
#   To purge old encrypted blobs from history entirely, run git-filter-repo
#   separately after this function completes (manual step — not automated here
#   because it rewrites all commit hashes and requires force-pushing).
#
# USAGE:
#   source lib/git-crypt.sh
#   cd ~/knowledge-genome-orchestrator/genome-dev
#   gcrypt_rotate_key "genome-dev"
#
# REQUIRES:
#   - The old key file at KEYS_DIR/<genome_name>.key  OR  the repo is already unlocked.
#   - Clean working tree (no uncommitted changes outside private/).
# ---------------------------------------------------------------------------
gcrypt_rotate_key() {
  local genome_name="$1"
  local old_key_path="${KEYS_DIR}/${genome_name}.key"
  local new_key_name="${genome_name}-rotated-$(date +%Y%m%d)"

  step "Key rotation: ${genome_name}"

  warn "SCOPE: this rotates the key for future commits only."
  warn "       Old git history retains blobs encrypted with the previous key."
  warn "       See function header in git-crypt.sh for full purge instructions."
  echo ""

  # 1. Unlock with old key (if not already unlocked)
  if git-crypt status 2>/dev/null | grep -q "encrypted"; then
    info "Repository appears to be locked. Attempting unlock..."
    if [[ -f "$old_key_path" ]]; then
      git-crypt unlock "$old_key_path"
      success "Unlocked with existing key."
    else
      error "Old key not found at: ${old_key_path}"
      error "Unlock manually before rotating: git-crypt unlock /path/to/${genome_name}.key"
      return 1
    fi
  else
    info "Repository is already unlocked — proceeding."
  fi

  # 2. Ensure working tree is clean (private files excluded — they will be re-staged)
  if ! git diff --quiet -- ':!raw/private' ':!wiki/private' 2>/dev/null; then
    error "Working tree has uncommitted changes outside private/. Commit or stash them first."
    return 1
  fi

  # 3. Remove old key material only (preserves .git/git-crypt/ structure)
  info "Removing old key material..."
  rm -rf .git/git-crypt/keys
  success "Old key material removed."

  # 4. Re-initialize git-crypt (generates a new symmetric key)
  info "Initializing new symmetric key..."
  git-crypt init
  success "New key generated."

  # 5. Re-stage private files so they are committed encrypted with the new key
  local staged=0
  # compgen -G requires bash 4+ for reliable glob expansion. macOS stock
  # bash is 3.2; use Homebrew bash (already recommended in README) for rotation.
  if compgen -G "raw/private/*" > /dev/null 2>&1; then
    git add raw/private/
    staged=1
  fi
  if compgen -G "wiki/private/*" > /dev/null 2>&1; then
    git add wiki/private/
    staged=1
  fi

  if [[ $staged -eq 1 ]]; then
    # Exclude .gitkeep-only commits — only commit if real content exists
    if ! git diff --cached --quiet; then
      git commit -m "security: rotate git-crypt key for ${genome_name}"
      success "Private files re-committed with new key."
    else
      info "Only .gitkeep files in private/ — no content commit needed."
    fi
  else
    info "No private files found to re-encrypt."
  fi

  # 6. Export new key
  gcrypt_export_key "$new_key_name"

  echo ""
  success "Key rotation complete for: ${genome_name}"
  echo ""
  warn "NEXT STEPS:"
  echo "  1. Push the new commit:  git push origin main"
  echo "  2. Upload the new key to Vaultwarden:"
  echo "       base64 < ${KEYS_DIR}/${new_key_name}.key"
  echo "       → Secure Note name: \"${genome_name} key\"  (replace existing)"
  echo "  3. Delete both key files from disk:"
  echo "       rm ${KEYS_DIR}/${genome_name}.key"
  echo "       rm ${KEYS_DIR}/${new_key_name}.key"
  echo "  4. Revoke access from any previous key holders."
  echo "  5. For full history purge (removes old encrypted blobs from git history):"
  echo "       git filter-repo --invert-paths --path raw/private --path wiki/private"
  echo "       git push --force origin main"
  echo "       (⚠ rewrites all commit hashes — coordinate with any collaborators)"
  echo ""
}

gcrypt_print_key_instructions() {
  local genome_name="$1"
  local v_url="${VAULTWARDEN_URL:-https://your-vaultwarden.com}"

  printf "\n  ── %b ──\n\n" "${BOLD}Key Management: ${genome_name}${NC}"
  echo "  1. Encode the key to base64:"
  echo "       base64 < ${KEYS_DIR}/${genome_name}.key"
  echo ""
  echo "  2. Save to Vaultwarden (${v_url}):"
  echo "       Name: \"${genome_name} key\""
  echo "       Note: <paste the base64 string>"
  echo ""
  echo "  3. Delete from disk:"
  echo "       rm ${KEYS_DIR}/${genome_name}.key"
  echo ""
  echo "  4. Runtime injection on AI server (no key on disk):"
  echo "       bw config server ${v_url}"
  echo "       export BW_SESSION=\$(bw unlock --passwordenv BW_MASTER_PASSWORD --raw)"
  echo "       git-crypt unlock <(bw get notes \"${genome_name} key\" --session \"\$BW_SESSION\" | base64 -d)"
  echo ""
  echo "     NOTE: use 'bw' (standard Bitwarden CLI), NOT 'bws'."
  echo "     'bws' is the Secrets Manager CLI and does not work with Vaultwarden."
}

gcrypt_print_runtime_model() {
  echo ""
  echo "  RUNTIME SECURITY MODEL:"
  echo "  ─────────────────────────────────────────────────────────────"
  echo "  On Forgejo (remote):"
  echo "    raw/private/ and wiki/private/ are opaque AES-256-CTR blobs."
  echo "    Collaborators without the key see binary in private/,"
  echo "    plaintext everywhere else. Git handles this gracefully."
  echo ""
  echo "  On your laptop:"
  echo "    Once unlocked, files are transparently decrypted by the git"
  echo "    smudge filter. Obsidian reads them as normal Markdown."
  echo ""
  echo "  On the AI VM:"
  echo "    Same as laptop when unlocked. Use runtime injection so the"
  echo "    key is never written to disk."
  echo ""
  echo "  Limitation:"
  echo "    Encryption does NOT protect against a full server compromise"
  echo "    where an attacker has root access to an already-unlocked repo."
  echo "    Runtime injection mitigates this risk."
  echo "  ─────────────────────────────────────────────────────────────"
  echo ""
}