#!/usr/bin/env python
#
# Copyright (C) 2016 The Android Open Source Project
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#      http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#

import os
import sys
import time

LOG_DIR = '/tmp'


def GetLatestLog():
    '''Find the latest vts runner log folder in log directory and return its content.

    Returns:
        (string, string), returns the latest log file path and log content
    '''
    folders = [os.path.join(LOG_DIR, folder_name)
               for folder_name in os.listdir(LOG_DIR)
               if os.path.isdir(os.path.join(LOG_DIR, folder_name)) and
               folder_name.startswith('vts-runner-log')]

    try:
        folders.sort(
            lambda folder1, folder2: int(os.path.getmtime(folder1) - os.path.getmtime(folder2)))
        folder_latest = folders[-1]
        log_path_latest = os.path.join(folder_latest,
                                       os.listdir(folder_latest)[0], 'latest',
                                       'test_run_details.txt')
        with open(log_path_latest, 'r') as log_latest:
            return (log_path_latest, log_latest.read())
    except Exception as e:
        return (None, None)


def StartMonitoring(path_only):
    '''Pull the latest vts runner log in a loop, and print out any new contents.

    Args:
        path_only: bool, only print out the latest log path in temporary directory.
    '''
    is_first_time = True
    last_log_path = None
    last_text = ''
    while True:
        log_path_latest, text_latest = GetLatestLog()

        if path_only:
            print log_path_latest
            return

        if log_path_latest is None:  # Case: cannot find any runner log
            time.sleep(2)
            continue

        if last_log_path == log_path_latest:
            text_new = text_latest[len(last_text):]
            last_text = text_latest
            if text_new:  # Case: runner log file changed
                if is_first_time:
                    is_first_time = False
                    print text_new
                    continue
                lines = text_new.split('\n')
                for l in lines:
                    print l
                    time.sleep(0.6 / len(lines))
            else:  # Case: runner log file didn't change
                time.sleep(1)
        else:  # Case: found a new runner log file
            last_text = ''
            last_log_path = log_path_latest
            print '\n' * 6 + '=' * 24 + 'new file' + '=' * 24 + '\n' * 6
            time.sleep(1)


def PrintUsage():
    print 'A script to read VTS Runner\'s log from temporary directory.'
    print 'Usage:'
    print '  -h, --help: print usage.'
    print '  -p, --path-only: print path to the latest runner file only.'
    print '                   You may pipe the result to vim for searching.'
    print '                   Example: script/monitor-runner-output.py --path-only | xargs gedit'
    print '  -m, --monitor: print VTS runner\'s output in close to real time'
    print '  If no argument is provided, this script will keep pulling the latest log and print it out.'


if __name__ == "__main__":
    argv = sys.argv
    path_only = False
    if len(argv) == 1 or argv[1] == '-h' or argv[1] == '--help':
        PrintUsage()
        exit()
    elif argv[1] == '-p' or argv[1] == '--path-only':
        path_only = True
    elif argv[1] == '-m' or argv[1] == '--monitor':
        path_only = False
    StartMonitoring(path_only)