#!/usr/bin/env bash
#
# fetch_ocr_model.sh — download and prepare the embedded OCR recognition model.
#
# RUN THIS ON YOUR DEV MACHINE. It downloads the PaddleOCR PP-OCRv4 mobile
# recognition inference model + the character dictionary, converts the Paddle
# inference model to ONNX, and places the results as:
#
#   assets/models/ocr/rec.onnx
#   assets/models/ocr/ppocr_keys_v1.txt
#
# These files are intentionally NOT committed; the app treats their absence as
# a clean no-op (OCR falls back to the native backend or returns nothing).
#
# Requirements: bash, curl, tar, and paddle2onnx (pip install paddle2onnx).
#
# proxy: export HTTPS_PROXY=http://127.0.0.1:7890 (and HTTP_PROXY) if you are
# behind a firewall/GFW that blocks the download hosts.

set -euo pipefail

# Resolve repo root relative to this script so it works from any cwd.
SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
REPO_ROOT="$(cd "${SCRIPT_DIR}/.." && pwd)"
OUT_DIR="${REPO_ROOT}/assets/models/ocr"
WORK_DIR="$(mktemp -d)"

# Canonical PaddleOCR sources. Swap to the en_ variant for English-only.
REC_INFER_URL="https://paddleocr.bj.bcebos.com/PP-OCRv4/chinese/ch_PP-OCRv4_rec_infer.tar"
# REC_INFER_URL="https://paddleocr.bj.bcebos.com/PP-OCRv4/english/en_PP-OCRv4_rec_infer.tar"
KEYS_URL="https://raw.githubusercontent.com/PaddlePaddle/PaddleOCR/main/ppocr/utils/ppocr_keys_v1.txt"

cleanup() { rm -rf "${WORK_DIR}"; }
trap cleanup EXIT

mkdir -p "${OUT_DIR}"

echo "==> Downloading recognition inference model"
curl -fL "${REC_INFER_URL}" -o "${WORK_DIR}/rec_infer.tar"

echo "==> Extracting"
tar -xf "${WORK_DIR}/rec_infer.tar" -C "${WORK_DIR}"
# The tarball extracts into a single directory; find it.
MODEL_DIR="$(find "${WORK_DIR}" -maxdepth 1 -type d -name '*_rec_infer' | head -n1)"
if [[ -z "${MODEL_DIR}" ]]; then
  echo "ERROR: could not locate the extracted *_rec_infer directory" >&2
  exit 1
fi

echo "==> Downloading character dictionary"
curl -fL "${KEYS_URL}" -o "${OUT_DIR}/ppocr_keys_v1.txt"

echo "==> Converting Paddle inference model to ONNX (requires paddle2onnx)"
if ! command -v paddle2onnx >/dev/null 2>&1; then
  echo "ERROR: paddle2onnx not found. Install with: pip install paddle2onnx" >&2
  exit 1
fi

paddle2onnx \
  --model_dir "${MODEL_DIR}" \
  --model_filename inference.pdmodel \
  --params_filename inference.pdiparams \
  --save_file "${OUT_DIR}/rec.onnx" \
  --opset_version 14 \
  --enable_onnx_checker True

echo "==> Done:"
echo "    ${OUT_DIR}/rec.onnx"
echo "    ${OUT_DIR}/ppocr_keys_v1.txt"