#!/usr/bin/env bash

set -euo pipefail

file_size_bytes() {
  local path="$1"
  if [ ! -f "$path" ]; then
    echo 0
    return
  fi
  if stat -c%s "$path" >/dev/null 2>&1; then
    stat -c%s "$path"
    return
  fi
  stat -f%z "$path"
}

min_traineddata_size_bytes() {
  local lang="$1"
  case "$lang" in
  eng) echo 1000000 ;;
  osd) echo 100000 ;;
  deu) echo 1000000 ;;
  *) echo 100000 ;;
  esac
}

download_traineddata() {
  local lang="$1"
  local dest="$2"
  local url="$3"
  local tmp="${dest}.tmp"
  local min_size
  min_size="$(min_traineddata_size_bytes "$lang")"

  rm -f "$tmp"

  for attempt in 1 2 3 4 5; do
    if curl -fsSL --retry 5 --retry-delay 5 --retry-all-errors "$url" -o "$tmp"; then
      local size
      size="$(file_size_bytes "$tmp")"
      if [ "$size" -ge "$min_size" ]; then
        mv -f "$tmp" "$dest"
        return 0
      fi
      echo "Downloaded ${lang}.traineddata too small (${size} bytes < ${min_size}), retrying..." >&2
    else
      echo "Failed to download ${lang}.traineddata (attempt ${attempt}), retrying..." >&2
    fi
    rm -f "$tmp"
    sleep "$attempt"
  done

  echo "ERROR: Failed to download valid ${lang}.traineddata after retries" >&2
  return 1
}

ensure_valid_traineddata() {
  local dest_dir="$1"
  local lang="$2"
  local url="$3"
  local dest_file="${dest_dir}/${lang}.traineddata"
  local min_size
  min_size="$(min_traineddata_size_bytes "$lang")"

  local size
  size="$(file_size_bytes "$dest_file")"
  if [ "$size" -ge "$min_size" ]; then
    return 0
  fi

  if [ -f "$dest_file" ]; then
    echo "Invalid ${lang}.traineddata at ${dest_file} (${size} bytes < ${min_size}); re-downloading..." >&2
    rm -f "$dest_file"
  fi

  download_traineddata "$lang" "$dest_file" "$url"
}

ensure_tessdata() {
  local dest="$1"
  mkdir -p "$dest"
  local dest_real
  dest_real="$(cd "$dest" && pwd -P)"

  local candidates=(
    "/opt/homebrew/share/tessdata"
    "/usr/local/opt/tesseract/share/tessdata"
    "/usr/share/tesseract-ocr/5/tessdata"
  )

  if [ -n "${PROGRAMFILES:-}" ] && command -v cygpath >/dev/null 2>&1; then
    candidates+=("$(cygpath -u "$PROGRAMFILES")/Tesseract-OCR/tessdata")
  fi
  if [ -d "/c/Program Files/Tesseract-OCR/tessdata" ]; then
    candidates+=("/c/Program Files/Tesseract-OCR/tessdata")
  fi

  for dir in "${candidates[@]}"; do
    if [ -f "$dir/eng.traineddata" ]; then
      local dir_real
      dir_real="$(cd "$dir" && pwd -P)"

      if [ "$dir_real" = "$dest_real" ]; then
        break
      fi

      for lang in eng osd deu; do
        if [ -f "$dir/$lang.traineddata" ]; then
          if [ -f "$dest/$lang.traineddata" ] &&
            [ "$dir_real/$lang.traineddata" -ef "$dest/$lang.traineddata" ]; then
            continue
          fi
          cp -f "$dir/$lang.traineddata" "$dest/"
        fi
      done
      break
    fi
  done

  ensure_valid_traineddata "$dest" "eng" "https://github.com/tesseract-ocr/tessdata_fast/raw/main/eng.traineddata"
  ensure_valid_traineddata "$dest" "osd" "https://github.com/tesseract-ocr/tessdata_fast/raw/main/osd.traineddata"
}

setup_tessdata() {
  local platform="${RUNNER_OS:-$(uname -s)}"

  case "$platform" in
  Linux)
    export TESSDATA_PREFIX="/usr/share/tesseract-ocr/5/tessdata"
    ;;
  macOS | Darwin)
    if [ -d "/opt/homebrew/opt/tesseract/share/tessdata" ]; then
      export TESSDATA_PREFIX="/opt/homebrew/opt/tesseract/share/tessdata"
    elif [ -d "/usr/local/opt/tesseract/share/tessdata" ]; then
      export TESSDATA_PREFIX="/usr/local/opt/tesseract/share/tessdata"
    else
      export TESSDATA_PREFIX="$HOME/Library/Application Support/kreuzberg-tesseract/tessdata"
    fi
    ;;
  Windows | MINGW* | MSYS* | CYGWIN*)
    export TESSDATA_PREFIX="${APPDATA:-${USERPROFILE:-}}/kreuzberg-tesseract/tessdata"
    ;;
  *)
    export TESSDATA_PREFIX="${REPO_ROOT:-$(pwd)}/target/tessdata"
    ;;
  esac

  ensure_tessdata "$TESSDATA_PREFIX"

  echo "✓ TESSDATA_PREFIX set to: $TESSDATA_PREFIX"
  [ -f "$TESSDATA_PREFIX/eng.traineddata" ] && echo "✓ eng.traineddata available"
  [ -f "$TESSDATA_PREFIX/osd.traineddata" ] && echo "✓ osd.traineddata available"
}

export -f ensure_tessdata
export -f setup_tessdata