#!/usr/bin/env python
# -*- coding: utf-8 -*-
"""Download latest LanguageTool distribution."""

import logging
import os
import re
import requests
import subprocess
import sys
import tempfile
import tqdm
from typing import Optional
import zipfile

from distutils.spawn import find_executable
from urllib.parse import urljoin
from .utils import (
    find_existing_language_tool_downloads,
    get_language_tool_download_path,
    LTP_JAR_DIR_PATH_ENV_VAR
)

# Create logger for this file.
logging.basicConfig(format='%(message)s')
logger = logging.getLogger(__name__)
logger.setLevel(logging.INFO)


# Get download host from environment or default.
BASE_URL = os.environ.get('LTP_DOWNLOAD_HOST', 'https://www.languagetool.org/download/')
FILENAME = 'LanguageTool-{version}.zip'

LTP_DOWNLOAD_VERSION = '6.4'

JAVA_VERSION_REGEX = re.compile(
    r'^(?:java|openjdk) version "(?P<major1>\d+)(|\.(?P<major2>\d+)\.[^"]+)"',
    re.MULTILINE)

# Updated for later versions of java
JAVA_VERSION_REGEX_UPDATED = re.compile(
    r'^(?:java|openjdk) [version ]?(?P<major1>\d+)\.(?P<major2>\d+)',
    re.MULTILINE)


def parse_java_version(version_text):
    """Return Java version (major1, major2).

    >>> parse_java_version('''java version "1.6.0_65"
    ... Java(TM) SE Runtime Environment (build 1.6.0_65-b14-462-11M4609)
    ... Java HotSpot(TM) 64-Bit Server VM (build 20.65-b04-462, mixed mode))
    ... ''')
    (1, 6)

    >>> parse_java_version('''
    ... openjdk version "1.8.0_60"
    ... OpenJDK Runtime Environment (build 1.8.0_60-b27)
    ... OpenJDK 64-Bit Server VM (build 25.60-b23, mixed mode))
    ... ''')
    (1, 8)

    """
    match = (
        re.search(JAVA_VERSION_REGEX, version_text)
        or re.search(JAVA_VERSION_REGEX_UPDATED, version_text)
    )
    if not match:
        raise SystemExit(
            'Could not parse Java version from """{}""".'.format(version_text))
    major1 = int(match.group('major1'))
    major2 = int(match.group('major2')) if match.group('major2') else 0
    return (major1, major2)


def confirm_java_compatibility():
    """ Confirms Java major version >= 8. """
    java_path = find_executable('java')
    if not java_path:
        raise ModuleNotFoundError(
            'No java install detected. '
            'Please install java to use language-tool-python.'
        )

    output = subprocess.check_output([java_path, '-version'],
                                     stderr=subprocess.STDOUT,
                                     universal_newlines=True)

    major_version, minor_version = parse_java_version(output)
    # Some installs of java show the version number like `14.0.1`
    # and others show `1.14.0.1`
    # (with a leading 1). We want to support both,
    # as long as the major version is >= 8.
    # (See softwareengineering.stackexchange.com/questions/175075/why-is-java-version-1-x-referred-to-as-java-x)
    if major_version == 1 and minor_version >= 8:
        return True
    elif major_version >= 8:
        return True
    else:
        raise SystemError('Detected java {}.{}. LanguageTool requires Java >= 8.'.format(major_version, minor_version))


def get_common_prefix(z):
    """Get common directory in a zip file if any."""
    name_list = z.namelist()
    if name_list and all(n.startswith(name_list[0]) for n in name_list[1:]):
        return name_list[0]
    return None


def http_get(url, out_file, proxies=None):
    """ Get contents of a URL and save to a file.
    """
    req = requests.get(url, stream=True, proxies=proxies)
    content_length = req.headers.get('Content-Length')
    total = int(content_length) if content_length is not None else None
    if req.status_code == 403:  # Not found on AWS
        raise Exception('Could not find at URL {}.'.format(url))
    progress = tqdm.tqdm(unit="B", unit_scale=True, total=total,
                         desc=f'Downloading LanguageTool {LTP_DOWNLOAD_VERSION}')
    for chunk in req.iter_content(chunk_size=1024):
        if chunk:  # filter out keep-alive new chunks
            progress.update(len(chunk))
            out_file.write(chunk)
    progress.close()


def unzip_file(temp_file, directory_to_extract_to):
    """ Unzips a .zip file to folder path. """
    logger.info(
        'Unzipping {} to {}.'.format(temp_file.name, directory_to_extract_to)
    )
    with zipfile.ZipFile(temp_file.name, 'r') as zip_ref:
        zip_ref.extractall(directory_to_extract_to)


def download_zip(url, directory):
    """ Downloads and unzips zip file from `url` to `directory`. """
    # Download file.
    downloaded_file = tempfile.NamedTemporaryFile(suffix='.zip', delete=False)
    http_get(url, downloaded_file)
    # Close the file so we can extract it.
    downloaded_file.close()
    # Extract zip file to path.
    unzip_file(downloaded_file, directory)
    # Remove the temporary file.
    os.remove(downloaded_file.name)
    # Tell the user the download path.
    logger.info('Downloaded {} to {}.'.format(url, directory))


def download_lt(language_tool_version: Optional[str] = LTP_DOWNLOAD_VERSION):
    confirm_java_compatibility()

    download_folder = get_language_tool_download_path()

    # Use the env var to the jar directory if it is defined
    # otherwise look in the download directory
    if os.environ.get(LTP_JAR_DIR_PATH_ENV_VAR):
        return

    # Make download path, if it doesn't exist.
    os.makedirs(download_folder, exist_ok=True)

    assert os.path.isdir(download_folder)
    old_path_list = find_existing_language_tool_downloads(download_folder)

    if language_tool_version:
        version = language_tool_version
        filename = FILENAME.format(version=version)
        language_tool_download_url = urljoin(BASE_URL, filename)
        dirname, _ = os.path.splitext(filename)
        extract_path = os.path.join(download_folder, dirname)

        if extract_path in old_path_list:
            return
        download_zip(language_tool_download_url, download_folder)


if __name__ == '__main__':
    sys.exit(download_lt())