import re
import os
import time

CHUNK_SIZE = 5

def read_lookup_table(lookup_table_path):
    """
   para ler a tabela de pesquisa e retornar um dicionário mapeando endereços IP para nomes de usuário.
    """
    ip_to_username = {}
    with open(lookup_table_path, 'r') as lookup_file:
        for line in lookup_file:
            parts = line.strip().split()
            if len(parts) == 2:
                ip, username = parts
                ip_to_username[ip] = username
            else:
                print(f"Skipping line in lookup table: {line.strip()}")
    return ip_to_username


def process_chunk(chunk, lookup_table_path):
    """
    Processa um pedaço de linhas do arquivo de log.
           
    """
    ip_to_username = read_lookup_table(lookup_table_path)
    modified_lines = []
    for line in chunk:
        modified_line = line
        match = re.search(r"\s+-\s+(\d+\.\d+\.\d+\.\d+)", modified_line)
        if match:
            ip_address = match.group(1).strip()
            if ip_address in ip_to_username:
                username = ip_to_username[ip_address]
                modified_line = re.sub(r"\s+-\s+(\d+\.\d+\.\d+\.\d+)", f"  {username:<15}    {ip_address}", modified_line)
        modified_lines.append(modified_line)
    return modified_lines

class LogTracker:
    def __init__(self, input_log_path, output_log_path, lookup_table_path):
        self.input_log_path = input_log_path
        self.output_log_path = output_log_path
        self.lookup_table_path = lookup_table_path
        self.last_position = 0

    def track_log(self):
        while True:
            with open(self.input_log_path, 'r') as infile:
                infile.seek(self.last_position)
                lines = infile.readlines()
                self.last_position = infile.tell()

            chunks = [lines[i:i + CHUNK_SIZE] for i in range(0, len(lines), CHUNK_SIZE)]
            for chunk in chunks:
                modified_lines = process_chunk(chunk, self.lookup_table_path)
                with open(self.output_log_path, 'a') as outfile:
                    outfile.writelines(modified_lines)

            # Sleep for a while before reading the log file again
            time.sleep(1)     

            
def modify_logfile_continuously(input_log_path, output_log_path, lookup_table_path):
    log_tracker = LogTracker(input_log_path, output_log_path, lookup_table_path)
    log_tracker.track_log()

if __name__ == "__main__":
    input_log_path = "logger.log"
    output_log_path = "log_modified.log"
    lookup_table_path = "lookup_table.tsv"
    modify_logfile_continuously(input_log_path, output_log_path, lookup_table_path)