#!/bin/bash
#
# Start reranker service from its backend-specific isolated venv.
#
set -euo pipefail

PROJECT_ROOT="$(cd "$(dirname "$0")/.." && pwd)"
cd "${PROJECT_ROOT}"

# Load .env without activating main venv.
# shellcheck source=scripts/lib/load_env.sh
source "${PROJECT_ROOT}/scripts/lib/load_env.sh"
load_env_file "${PROJECT_ROOT}/.env"
# shellcheck source=scripts/lib/reranker_backend_env.sh
source "${PROJECT_ROOT}/scripts/lib/reranker_backend_env.sh"

RERANKER_HOST="${RERANKER_HOST:-0.0.0.0}"
RERANKER_PORT="${RERANKER_PORT:-6007}"
RERANK_BACKEND="${RERANK_BACKEND:-$(detect_rerank_backend "${PROJECT_ROOT}")}"
RERANKER_VENV="${RERANKER_VENV:-$(reranker_backend_venv_dir "${PROJECT_ROOT}" "${RERANK_BACKEND}")}"
PYTHON_BIN="${RERANKER_VENV}/bin/python"

if [[ ! -x "${PYTHON_BIN}" ]]; then
  echo "ERROR: reranker venv not found for backend ${RERANK_BACKEND}: ${RERANKER_VENV}" >&2
  echo "Please run: ./scripts/setup_reranker_venv.sh ${RERANK_BACKEND}" >&2
  exit 1
fi

# Keep vLLM/triton/torch caches out of system disk.
RERANKER_RUNTIME_DIR="${RERANKER_RUNTIME_DIR:-${PROJECT_ROOT}/.runtime/reranker}"
mkdir -p "${RERANKER_RUNTIME_DIR}/home" \
         "${RERANKER_RUNTIME_DIR}/cache" \
         "${RERANKER_RUNTIME_DIR}/config" \
         "${RERANKER_RUNTIME_DIR}/triton" \
         "${RERANKER_RUNTIME_DIR}/torch_compile" \
         "${RERANKER_RUNTIME_DIR}/tmp"
export HOME="${RERANKER_RUNTIME_DIR}/home"
export XDG_CACHE_HOME="${RERANKER_RUNTIME_DIR}/cache"
export XDG_CONFIG_HOME="${RERANKER_RUNTIME_DIR}/config"
export TRITON_CACHE_DIR="${RERANKER_RUNTIME_DIR}/triton"
export TORCHINDUCTOR_CACHE_DIR="${RERANKER_RUNTIME_DIR}/torch_compile"
export TMPDIR="${RERANKER_RUNTIME_DIR}/tmp"
export VLLM_NO_USAGE_STATS="${VLLM_NO_USAGE_STATS:-1}"
export PATH="${RERANKER_VENV}/bin:${PATH}"

if [[ "${RERANK_BACKEND}" == qwen3_gguf* ]]; then
  export HF_HUB_DISABLE_XET="${HF_HUB_DISABLE_XET:-1}"
fi

if [[ "${RERANK_BACKEND}" == "qwen3_vllm" || "${RERANK_BACKEND}" == "qwen3_vllm_score" || "${RERANK_BACKEND}" == "qwen3_transformers_packed" ]]; then
  if ! command -v nvidia-smi >/dev/null 2>&1 || ! nvidia-smi >/dev/null 2>&1; then
    echo "ERROR: ${RERANK_BACKEND} backend requires NVIDIA GPU, but nvidia-smi is unavailable." >&2
    exit 1
  fi
  if ! "${PYTHON_BIN}" - <<'PY'
try:
    import torch
    try:
        import vllm  # noqa: F401
    except Exception:
        pass
    if not torch.cuda.is_available():
        raise SystemExit(1)
except Exception:
    raise SystemExit(1)
PY
  then
    if [[ "${RERANK_BACKEND}" == "qwen3_transformers_packed" ]]; then
      echo "ERROR: ${RERANK_BACKEND} backend requires torch + CUDA runtime in ${RERANKER_VENV}." >&2
    else
      echo "ERROR: ${RERANK_BACKEND} backend requires vllm + CUDA runtime in ${RERANKER_VENV}." >&2
    fi
    echo "Please run: ./scripts/setup_reranker_venv.sh ${RERANK_BACKEND} and verify CUDA is available." >&2
    exit 1
  fi
fi

if [[ "${RERANK_BACKEND}" == qwen3_gguf* ]]; then
  gguf_check_status=0
  "${PYTHON_BIN}" - <<'PY' || gguf_check_status=$?
try:
    import llama_cpp
    if hasattr(llama_cpp, "llama_supports_gpu_offload") and not llama_cpp.llama_supports_gpu_offload():
        raise SystemExit(2)
except Exception:
    raise SystemExit(1)
PY
  if [[ "${gguf_check_status}" != "0" ]]; then
    if [[ "${gguf_check_status}" == "2" ]]; then
      echo "ERROR: ${RERANK_BACKEND} backend detected a CPU-only llama-cpp-python build in ${RERANKER_VENV}." >&2
      echo "Please rerun: ./scripts/setup_reranker_venv.sh ${RERANK_BACKEND}" >&2
    else
      echo "ERROR: ${RERANK_BACKEND} backend requires llama-cpp-python in ${RERANKER_VENV}." >&2
      echo "Please run: ./scripts/setup_reranker_venv.sh ${RERANK_BACKEND}" >&2
    fi
    exit 1
  fi
fi

echo "========================================"
echo "Starting Reranker Service"
echo "========================================"
echo "Python: ${PYTHON_BIN}"
echo "Host: ${RERANKER_HOST}"
echo "Port: ${RERANKER_PORT}"
echo "Backend: ${RERANK_BACKEND}"
echo "Runtime dir: ${RERANKER_RUNTIME_DIR}"
echo

exec "${PYTHON_BIN}" -m uvicorn reranker.server:app \
  --host "${RERANKER_HOST}" \
  --port "${RERANKER_PORT}" \
  --workers 1