import shutil
import subprocess
import sys

from http_host_lib.config import config
from http_host_lib.get_version_shared import get_versions_for_area
from http_host_lib.utils import download_file_aria2, get_remote_file_size


def download_area_version(area: str, version: str) -> bool:
    """
    Downloads and uncompresses tiles.btrfs files from the btrfs bucket

    "latest" version means the latest in the remote bucket
    "deployed" version means to read the currently deployed version string from the config dir
    """

    if area not in config.areas:
        sys.exit(f'  Please specify area: {config.areas}')

    versions = get_versions_for_area(area)
    if not versions:
        print(f'  No versions found for {area}')
        return False

    # latest version
    if version == 'latest':
        selected_version = versions[-1]

    # deployed version
    elif version == 'deployed':
        try:
            selected_version = (config.deployed_versions_dir / f'{area}.txt').read_text().strip()
        except Exception:
            return False

    # specific version
    else:
        if version not in versions:
            available_versions_str = '\n'.join(versions)
            print(
                f'  Requested version is not available.\nAvailable versions for {area}:\n{available_versions_str}'
            )
            return False
        selected_version = version

    return download_and_extract_btrfs(area, selected_version)


def download_and_extract_btrfs(area: str, version: str) -> bool:
    """
    returns True if download successful, False if skipped
    """

    print(f'Downloading btrfs: {area} {version}')

    version_dir = config.runs_dir / area / version
    btrfs_file = version_dir / 'tiles.btrfs'
    if btrfs_file.exists():
        print('  file exists, skipping download')
        return False

    temp_dir = config.runs_dir / '_tmp'
    shutil.rmtree(temp_dir, ignore_errors=True)
    temp_dir.mkdir(parents=True)

    url = f'https://btrfs.openfreemap.com/areas/{area}/{version}/tiles.btrfs.gz'

    # check disk space
    disk_free = shutil.disk_usage(temp_dir).free
    file_size = get_remote_file_size(url)
    if not file_size:
        print(f'  cannot get remote file size for {url}')
        return False

    needed_space = file_size * 3
    if disk_free < needed_space:
        print(f'  not enough disk space. Needed: {needed_space}, free space: {disk_free}')
        return False

    target_file = temp_dir / 'tiles.btrfs.gz'
    download_file_aria2(url, target_file)

    print('  uncompressing...')
    subprocess.run(['unpigz', temp_dir / 'tiles.btrfs.gz'], check=True)
    btrfs_src = temp_dir / 'tiles.btrfs'

    shutil.rmtree(version_dir, ignore_errors=True)
    version_dir.mkdir(parents=True)

    btrfs_src.rename(btrfs_file)

    shutil.rmtree(temp_dir)
    return True