import os
import random

# Directory containing the shard JSONL files
shard_directory = "/path/to/shard/directory"

# Get a list of all JSONL files in the directory
shard_files = [f for f in os.listdir(shard_directory) if f.endswith('.jsonl')]

# Function to read a random number of lines (between min_lines and max_lines) from a file
def read_random_lines(filename, min_lines, max_lines):
    selected_lines = []
    num_lines = random.randint(min_lines, max_lines)

    with open(filename, 'r') as file:
        lines = list(file)
        if len(lines) <= num_lines:
            return lines
        selected_lines = random.sample(lines, num_lines)

    return selected_lines

# Function to combine shards
def combine_shards(output_filename, num_combinations):
    with open(output_filename, 'w') as output_file:
        for _ in range(num_combinations):
            selected_shard_file = random.choice(shard_files)
            lines = read_random_lines(os.path.join(shard_directory, selected_shard_file), 5000, 10000)
            output_file.writelines(lines)

# Example usage
combine_shards("/path/to/output/combined_shards.jsonl", 10)