#!/usr/bin/env bash
set -euo pipefail

# Required tools: git-lfs, coreutils
# Already executed: huggingface-cli lfs-enable-largefiles .

# Your >50GB file list
BIG_FILES=(
  "fix_compute/c4_12B.json"        # 58 GB
  "fix_compute/c4_13B5.json"       # 66 GB
  "fix_compute/c4_23B.json"        # 112 GB
  "fix_compute/c4_23B8.json"       # 116 GB
  "fix_compute/c4_23B8_2ep.json"   # 58 GB
  "fix_compute/c4_23B_2ep.json"    # 56 GB
  "fix_compute/c4_40B.json"        # 195 GB
  "fix_compute/c4_40B_2ep.json"    # 97 GB
)

# Target size (GB), used to estimate lines per shard; actual target includes 10% safety margin
TARGET_GB=10
SAFETY=0.9            # Target size = TARGET_GB * SAFETY
OUTDIR="data_line_shards"
SUFFIX=".jsonl"       # Add .jsonl suffix to all shards to indicate they are JSONL

# Ensure large files are enabled
huggingface-cli lfs-enable-largefiles .

# LFS tracking (line-split files + possible .json/.jsonl original files)
git lfs track "*.jsonl"
git lfs track "*.json"
git lfs track "${OUTDIR}/*.part-*${SUFFIX}"
git add .gitattributes

mkdir -p "${OUTDIR}"

bytes_in_gb=$((1024*1024*1024))
target_bytes=$(python3 - <<PY
print(int(${TARGET_GB}*${bytes_in_gb}*${SAFETY}))
PY
)

calc_lines_per_shard() {
  local f="$1"
  # Count total bytes, total lines (may be large, wc -l will take a while)
  local size lines
  size=$(stat -c%s "$f" 2>/dev/null || stat -f%z "$f")
  lines=$(wc -l < "$f" || echo 0)
  if [[ "$lines" -le 0 ]]; then
    # No lines detected, fallback to fixed line count (avoid division by zero); you can also specify manually
    echo 10000000
    return
  fi

  # Average bytes per line
  local bpl=$(( size / lines ))
  if [[ "$bpl" -le 0 ]]; then
    bpl=1
  fi

  # Calculate lines per shard (floor division)
  local lps=$(( target_bytes / bpl ))
  # Reasonable lower limit, avoid too many shards; also avoid exceeding total file lines
  if [[ "$lps" -lt 100000 ]]; then
    lps=100000
  fi
  echo "$lps"
}

shard_one_jsonl() {
  local f="$1"
  [[ -f "$f" ]] || { echo "Skip: file not found $f"; return; }

  # local base="$(basename "$f")"
  # local stem="${base%.*}"                  # Remove extension
  # local prefix="${OUTDIR}/${stem}.part-"

  # echo "==> Estimating lines per shard: $f"
  # local LPS
  # LPS=$(calc_lines_per_shard "$f")
  # echo "    Lines per shard ~ ${LPS} lines (target ${TARGET_GB}GB, including safety margin)"

  # echo "==> Splitting by lines: $f → ${prefix}000${SUFFIX}, ${prefix}001${SUFFIX}, ..."
  # # Avoid duplicate splitting
  # if compgen -G "${prefix}*${SUFFIX}" >/dev/null; then
  #   echo "    Shards already exist, skipping split"
  # else
  #   # -d numeric suffix, -a 3 generates 000..999; change to -a 4 if more needed
  #   split -d -a 3 -l "$LPS" --additional-suffix="${SUFFIX}" "$f" "$prefix"
  # fi

  echo "==> Replacing original file in staging area with shards (keeping working directory original file)"
  git rm --cached -f "$f" || true

  # echo "==> Adding shards to LFS"
  # git add "${prefix}"*"${SUFFIX}"

  # echo "Completed: $f"
}

for f in "${BIG_FILES[@]}"; do
  shard_one_jsonl "$f"
done

git commit -m "Line-split >50GB JSONL-like files into ~${TARGET_GB}GB LFS shards (${OUTDIR})"