#!/bin/bash
set -euo pipefail

# ── Config ────────────────────────────────────────────────────────────────────
BASE_URL="https://dg-familienarchiv.de"
BATCH_SIZE=10
OUTPUT_DIR="./paperless-download"
MAX_RETRIES=3
RETRY_DELAY=10   # seconds between retries
# ─────────────────────────────────────────────────────────────────────────────

# Prompt for credentials
USERNAME="berit.cram@gmx.de"
PASSWORD="LifeOfNewYork1;)"

echo "Authenticating..."
AUTH_BODY=$(jq -n --arg u "$USERNAME" --arg p "$PASSWORD" '{username: $u, password: $p}')
AUTH_RESP=$(curl -s -X POST \
  -H "Content-Type: application/json" \
  -d "$AUTH_BODY" \
  "$BASE_URL/api/token/")
TOKEN=$(echo "$AUTH_RESP" | jq -r '.token')

if [ -z "$TOKEN" ] || [ "$TOKEN" = "null" ]; then
  echo "Authentication failed. Server responded:" >&2
  echo "$AUTH_RESP" >&2
  exit 1
fi
echo "Authenticated."

# ── Collect all document IDs ───────────────────────────────────────────────
echo "Fetching document list..."
ALL_IDS=()
PAGE=1
while true; do
  RESP=$(curl -s \
    -H "Authorization: Token $TOKEN" \
    "$BASE_URL/api/documents/?page=$PAGE&page_size=100")

  IDS=$(echo "$RESP" | jq -r '.results[].id' | tr -d '\r' | grep -E '^[0-9]+$')
  [ -z "$IDS" ] && break
  while IFS= read -r id; do
    ALL_IDS+=("$id")
  done <<< "$IDS"

  NEXT=$(echo "$RESP" | jq -r '.next')
  [ "$NEXT" = "null" ] && break
  PAGE=$((PAGE + 1))
done

TOTAL=${#ALL_IDS[@]}
echo "Found $TOTAL documents."

# ── Download in batches ────────────────────────────────────────────────────
mkdir -p "$OUTPUT_DIR"

BATCH_NUM=0
START=0
while [ $START -lt $TOTAL ]; do
  END=$(( START + BATCH_SIZE ))
  [ $END -gt $TOTAL ] && END=$TOTAL
  BATCH_IDS=("${ALL_IDS[@]:$START:$((END - START))}")
  BATCH_NUM=$((BATCH_NUM + 1))

  PADDED=$(printf "%03d" "$BATCH_NUM")
  ZIP_FILE="$OUTPUT_DIR/batch_$PADDED.zip"
  BATCH_DIR="$OUTPUT_DIR/batch_$PADDED"

  # Skip already-extracted batches (resume support)
  if [ -d "$BATCH_DIR" ]; then
    echo "Skipping batch $BATCH_NUM (already extracted)."
    START=$END
    continue
  fi

  echo "Downloading batch $BATCH_NUM (docs $((START+1))–$END of $TOTAL)..."

  JSON_IDS=$(printf '%s\n' "${BATCH_IDS[@]}" | grep -E '^[0-9]+$' | jq -s '[.[] | tonumber]')

  ATTEMPT=0
  SUCCESS=false
  while [ $ATTEMPT -lt $MAX_RETRIES ]; do
    ATTEMPT=$((ATTEMPT + 1))

    CONTENT_TYPE=$(curl -s --max-time 300 -X POST \
      -H "Authorization: Token $TOKEN" \
      -H "Content-Type: application/json" \
      -d "{\"documents\": $JSON_IDS, \"content\": \"originals\"}" \
      "$BASE_URL/api/documents/bulk_download/" \
      -D - \
      --output "$ZIP_FILE" | grep -i '^content-type:' | tr -d '\r')

    if [ ! -s "$ZIP_FILE" ]; then
      echo "  Attempt $ATTEMPT: empty response, retrying in ${RETRY_DELAY}s..." >&2
      rm -f "$ZIP_FILE"
      sleep $RETRY_DELAY
      continue
    fi

    if echo "$CONTENT_TYPE" | grep -qi 'zip\|octet-stream'; then
      SUCCESS=true
      break
    else
      echo "  Attempt $ATTEMPT: unexpected response (${CONTENT_TYPE}):" >&2
      cat "$ZIP_FILE" >&2
      rm -f "$ZIP_FILE"
      sleep $RETRY_DELAY
    fi
  done

  if [ "$SUCCESS" = false ]; then
    echo "  Batch $BATCH_NUM failed after $MAX_RETRIES attempts, skipping." >&2
    START=$END
    continue
  fi

  mkdir -p "$BATCH_DIR"
  unzip -q "$ZIP_FILE" -d "$BATCH_DIR"
  rm "$ZIP_FILE"
  echo "  Extracted to $BATCH_DIR/"

  START=$END
done

echo "Done. All files saved to $OUTPUT_DIR/"