#!/bin/bash
# Extract all shard_*.tar.gz in parallel with progress display.
# Usage: bash extract_shards.sh [shard_dir] [output_dir] [num_workers]

SHARD_DIR="${1:-data}"
OUT_DIR="${2:-llava178k_merged}"
WORKERS="${3:-8}"

mkdir -p "$OUT_DIR"

shards=("$SHARD_DIR"/shard_*.tar.gz)
total=${#shards[@]}
echo "Found $total shards, extracting with $WORKERS workers -> $OUT_DIR"

# Use GNU parallel if available, otherwise xargs
if command -v parallel &>/dev/null; then
    printf '%s\n' "${shards[@]}" | parallel -j "$WORKERS" --bar \
        tar xf {} --strip-components=1 -C "$OUT_DIR/"
else
    printf '%s\n' "${shards[@]}" | xargs -P "$WORKERS" -I{} \
        bash -c 'echo "Extracting {}..." && tar xf "{}" --strip-components=1 -C '"$OUT_DIR/"
fi

echo "Done. Extracted $total shards to $OUT_DIR/"