feat(ocr): extend model script with automatic OCR evaluation

Downloads both Kraken models, then runs each against 4 sample PDFs
from the import folder (Eu-0693, Eu-0692, W-0150, W-0575). Output
goes to ocr-model-evaluation/<model-name>/<doc>.txt for side-by-side
comparison.

Usage:
  ./scripts/download-kraken-models.sh           # download + evaluate
  ./scripts/download-kraken-models.sh --eval-only  # re-run evaluation
  ./scripts/download-kraken-models.sh --activate 1  # pick winner

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

scripts/download-kraken-models.sh

@@ -1,13 +1,13 @@
 #!/bin/bash
 set -euo pipefail
 
-# Downloads Kraken HTR models for German Kurrent/Suetterlin into the ocr_models volume.
-# Run this once after first deployment, or whenever you want to switch models.
+# Downloads Kraken HTR models, runs OCR evaluation on sample PDFs, and activates the winner.
 #
 # Usage:
-#   ./scripts/download-kraken-models.sh              # download both candidates
-#   ./scripts/download-kraken-models.sh --activate 1  # activate model 1 (german_kurrent_manu_9)
-#   ./scripts/download-kraken-models.sh --activate 2  # activate model 2 (kurrent-de)
+#   ./scripts/download-kraken-models.sh                # download models + run evaluation
+#   ./scripts/download-kraken-models.sh --activate 1   # activate model 1 (german_kurrent_manu_9)
+#   ./scripts/download-kraken-models.sh --activate 2   # activate model 2 (kurrent-de)
+#   ./scripts/download-kraken-models.sh --eval-only    # re-run evaluation (models already downloaded)
 
 COMPOSE_SERVICE="ocr-service"
 MODEL_DIR="/app/models"
@@ -21,6 +21,10 @@ MODEL_2_NAME="kurrent-de"
 MODEL_2_DESC="Broad German Kurrent coverage (HTR-United)"
 MODEL_2_PATH="$MODEL_DIR/$MODEL_2_NAME.mlmodel"
 
+EVAL_PDFS=("Eu-0693.pdf" "Eu-0692.pdf" "W-0150.pdf" "W-0575.pdf")
+IMPORT_DIR="./import"
+OUTPUT_BASE="./ocr-model-evaluation"
+
 # ─── Functions ────────────────────────────────────────────────────────────────
 
 download_models() {
@@ -29,31 +33,81 @@ download_models() {
 
     echo "Model 1: $MODEL_1_NAME"
     echo "  $MODEL_1_DESC"
-    docker compose run --rm "$COMPOSE_SERVICE" \
-        kraken get "$MODEL_1_NAME" -o "$MODEL_1_PATH"
+    docker compose run --rm "$COMPOSE_SERVICE" kraken get "$MODEL_1_NAME" -o "$MODEL_1_PATH"
     echo ""
 
     echo "Model 2: $MODEL_2_NAME"
     echo "  $MODEL_2_DESC"
-    docker compose run --rm "$COMPOSE_SERVICE" \
-        kraken get "$MODEL_2_NAME" -o "$MODEL_2_PATH"
+    docker compose run --rm "$COMPOSE_SERVICE" kraken get "$MODEL_2_NAME" -o "$MODEL_2_PATH"
     echo ""
 
-    echo "Both models downloaded. To test them against a sample document:"
+    echo "Both models downloaded."
+}
+
+run_evaluation() {
     echo ""
-    echo "  # Copy a sample Kurrent scan into the container:"
-    echo "  docker cp sample-kurrent.png archive-ocr:/tmp/sample.png"
+    echo "═══════════════════════════════════════════════════════"
+    echo "  Running OCR evaluation on ${#EVAL_PDFS[@]} documents"
+    echo "═══════════════════════════════════════════════════════"
     echo ""
-    echo "  # Test model 1:"
-    echo "  docker compose exec ocr-service kraken -i /tmp/sample.png /tmp/out1.txt segment -bl ocr -m $MODEL_1_PATH"
-    echo "  docker compose exec ocr-service cat /tmp/out1.txt"
+
+    # Create output directories on the host
+    local dir_1="$OUTPUT_BASE/$MODEL_1_NAME"
+    local dir_2="$OUTPUT_BASE/$MODEL_2_NAME"
+    mkdir -p "$dir_1" "$dir_2"
+
+    for pdf in "${EVAL_PDFS[@]}"; do
+        local src="$IMPORT_DIR/$pdf"
+        local basename="${pdf%.pdf}"
+
+        if [[ ! -f "$src" ]]; then
+            echo "SKIP: $src not found"
+            continue
+        fi
+
+        echo "──── $pdf ────"
+
+        # Model 1
+        echo "  Model 1: $MODEL_1_NAME ..."
+        docker compose run --rm \
+            -v "$(cd "$IMPORT_DIR" && pwd):/eval-input:ro" \
+            -v "$(cd "$dir_1" && pwd):/eval-output" \
+            "$COMPOSE_SERVICE" \
+            kraken -i "/eval-input/$pdf" "/eval-output/${basename}.txt" segment -bl ocr -m "$MODEL_1_PATH" \
+            2>/dev/null || echo "  ⚠ Model 1 failed on $pdf"
+
+        # Model 2
+        echo "  Model 2: $MODEL_2_NAME ..."
+        docker compose run --rm \
+            -v "$(cd "$IMPORT_DIR" && pwd):/eval-input:ro" \
+            -v "$(cd "$dir_2" && pwd):/eval-output" \
+            "$COMPOSE_SERVICE" \
+            kraken -i "/eval-input/$pdf" "/eval-output/${basename}.txt" segment -bl ocr -m "$MODEL_2_PATH" \
+            2>/dev/null || echo "  ⚠ Model 2 failed on $pdf"
+
+        echo ""
+    done
+
+    echo "═══════════════════════════════════════════════════════"
+    echo "  Evaluation complete. Results:"
     echo ""
-    echo "  # Test model 2:"
-    echo "  docker compose exec ocr-service kraken -i /tmp/sample.png /tmp/out2.txt segment -bl ocr -m $MODEL_2_PATH"
-    echo "  docker compose exec ocr-service cat /tmp/out2.txt"
+    echo "  Model 1 ($MODEL_1_NAME):"
+    for f in "$dir_1"/*.txt; do
+        [[ -f "$f" ]] && echo "    $(basename "$f"): $(wc -l < "$f") lines, $(wc -c < "$f") bytes"
+    done
     echo ""
-    echo "Then activate the better model:"
-    echo "  ./scripts/download-kraken-models.sh --activate 1   # or 2"
+    echo "  Model 2 ($MODEL_2_NAME):"
+    for f in "$dir_2"/*.txt; do
+        [[ -f "$f" ]] && echo "    $(basename "$f"): $(wc -l < "$f") lines, $(wc -c < "$f") bytes"
+    done
+    echo ""
+    echo "  Compare the outputs side by side:"
+    echo "    diff $dir_1/Eu-0693.txt $dir_2/Eu-0693.txt"
+    echo ""
+    echo "  Then activate the better model:"
+    echo "    ./scripts/download-kraken-models.sh --activate 1   # $MODEL_1_NAME"
+    echo "    ./scripts/download-kraken-models.sh --activate 2   # $MODEL_2_NAME"
+    echo "═══════════════════════════════════════════════════════"
 }
 
 activate_model() {
@@ -61,13 +115,11 @@ activate_model() {
     case "$choice" in
         1)
             echo "Activating model 1: $MODEL_1_NAME"
-            docker compose run --rm "$COMPOSE_SERVICE" \
-                cp "$MODEL_1_PATH" "$ACTIVE_MODEL"
+            docker compose run --rm "$COMPOSE_SERVICE" cp "$MODEL_1_PATH" "$ACTIVE_MODEL"
             ;;
         2)
             echo "Activating model 2: $MODEL_2_NAME"
-            docker compose run --rm "$COMPOSE_SERVICE" \
-                cp "$MODEL_2_PATH" "$ACTIVE_MODEL"
+            docker compose run --rm "$COMPOSE_SERVICE" cp "$MODEL_2_PATH" "$ACTIVE_MODEL"
             ;;
         *)
             echo "Error: --activate expects 1 or 2"
@@ -82,8 +134,15 @@ activate_model() {
 
 # ─── Main ─────────────────────────────────────────────────────────────────────
 
-if [[ "${1:-}" == "--activate" ]]; then
-    activate_model "${2:-}"
-else
-    download_models
-fi
+case "${1:-}" in
+    --activate)
+        activate_model "${2:-}"
+        ;;
+    --eval-only)
+        run_evaluation
+        ;;
+    *)
+        download_models
+        run_evaluation
+        ;;
+esac