#!/usr/bin/env bash
set -euo pipefail

POLYGUARD_ROOT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
POLYGUARD_VENV_DIR="${POLYGUARD_VENV_DIR:-$POLYGUARD_ROOT_DIR/.venv}"
POLYGUARD_PYTHON_BIN="$POLYGUARD_VENV_DIR/bin/python"
POLYGUARD_PIP_BIN="$POLYGUARD_VENV_DIR/bin/pip"
POLYGUARD_REQ_MARKER="$POLYGUARD_VENV_DIR/.requirements.sha256"

requirements_fingerprint() {
  if command -v shasum >/dev/null 2>&1; then
    shasum -a 256 "$POLYGUARD_ROOT_DIR/requirements.txt" "$POLYGUARD_ROOT_DIR/pyproject.toml" | shasum -a 256 | awk '{print $1}'
    return
  fi
  if command -v sha256sum >/dev/null 2>&1; then
    sha256sum "$POLYGUARD_ROOT_DIR/requirements.txt" "$POLYGUARD_ROOT_DIR/pyproject.toml" | sha256sum | awk '{print $1}'
    return
  fi
  # Fallback deterministic value when hash tools are unavailable.
  echo "no_hash_tool"
}

venv_has_required_imports() {
  "$POLYGUARD_PYTHON_BIN" - <<'PY'
modules = [
    "fastapi",
    "uvicorn",
    "pydantic",
    "yaml",
    "numpy",
    "pandas",
    "pyarrow",
    "sklearn",
    "requests",
    "httpx",
    "trl",
    "transformers",
    "accelerate",
    "peft",
    "openenv",
]
missing = []
for mod in modules:
    try:
        __import__(mod)
    except Exception:
        missing.append(mod)
if missing:
    raise SystemExit(1)
PY
}

ensure_polyguard_venv() {
  if [[ ! -x "$POLYGUARD_PYTHON_BIN" ]]; then
    python3 -m venv "$POLYGUARD_VENV_DIR"
  fi
}

sync_polyguard_requirements() {
  ensure_polyguard_venv
  local target_hash current_hash
  target_hash="$(requirements_fingerprint)"
  current_hash=""
  if [[ -f "$POLYGUARD_REQ_MARKER" ]]; then
    current_hash="$(cat "$POLYGUARD_REQ_MARKER")"
  fi
  if [[ "${POLYGUARD_FORCE_SYNC:-false}" != "true" && -n "$current_hash" && "$current_hash" == "$target_hash" ]]; then
    return
  fi
  if [[ "${POLYGUARD_FORCE_SYNC:-false}" != "true" ]] && venv_has_required_imports; then
    echo "$target_hash" > "$POLYGUARD_REQ_MARKER"
    return
  fi
  "$POLYGUARD_PIP_BIN" install --disable-pip-version-check --upgrade pip setuptools wheel
  "$POLYGUARD_PIP_BIN" install --disable-pip-version-check -r "$POLYGUARD_ROOT_DIR/requirements.txt"
  "$POLYGUARD_PIP_BIN" install --disable-pip-version-check --no-build-isolation -e "$POLYGUARD_ROOT_DIR"
  echo "$target_hash" > "$POLYGUARD_REQ_MARKER"
}

activate_polyguard_path() {
  export PATH="$POLYGUARD_VENV_DIR/bin:$PATH"
  export PYTHONPATH="${PYTHONPATH:-}:$POLYGUARD_ROOT_DIR"
}