# Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
# SPDX-License-Identifier: MIT-0

#!/usr/bin/python
import gzip
import os
import signal
import sys
import time
from util.line_pattern import LinePattern


class FakeLogs:
    """Entrypoint to generate fake logs (into file or stdout)."""

    def __init__(self, filename=None, num_lines=10, file_format="elf", line_pattern=None, sleep=None):
        self.filename = filename
        self.num_lines = num_lines
        self.sleep = sleep
        self.line_pattern = LinePattern(file_format=file_format) if line_pattern is None else line_pattern
        self.line_pattern.sleep = sleep

        if self.num_lines < 0:
            sys.exit("The number of lines cannot be negative '^_^")

        if self.sleep == 0 and self.num_lines == 0:
            sys.exit("Do not use --sleep=0 and --num=0 in the same time '^_^")

        self._init_file()

    def _init_file(self):
        self.file = sys.stdout
        if self.filename is not None:
            dirname = os.path.dirname(self.filename)
            if dirname != "":
                os.makedirs(dirname, exist_ok=True)

            _open = gzip.open if self.filename.lower().endswith(".gz") else open
            self.file = _open(self.filename, "wt")

    def _close_file(self):
        if self.filename is not None:
            self.file.close()

    def run(self):
        """Main method to generate fake logs."""
        if self.sleep is not None:
            self._write_line_and_sleep()
            return

        for _ in range(0, self.num_lines):
            self._write_line()

        self._close_file()

    def _write_line_and_sleep(self):
        def signal_handler(*_):
            print("Goodbye!")
            self._close_file()
            sys.exit(0)

        signal.signal(signal.SIGINT, signal_handler)
        num_lines = self.num_lines
        infinite = self.num_lines == 0

        while infinite or num_lines > 0:
            self._write_line(flush=True)
            time.sleep(self.sleep)
            num_lines -= 1

    def _write_line(self, flush=False):
        line = self.line_pattern.create_line()
        print(line, file=self.file, flush=flush)