import asyncio
import subprocess
from multiprocessing import Event, Manager
from pathlib import Path
from typing import List

from sqlalchemy.orm import Session

from modules.map.models import MapFile
from wrolpi.cmd import which
from wrolpi.common import get_media_directory, walk, logger, wrol_mode_check
from wrolpi.dates import now, timedelta_to_timestamp
from wrolpi.db import optional_session, get_db_session
from wrolpi.vars import PYTEST, PROJECT_DIR

logger = logger.getChild(__name__)

IMPORT_EVENT = Event()
IMPORTING = Manager().dict()
IMPORTING['pbf'] = None


def get_map_directory() -> Path:
    return get_media_directory() / 'map'


def get_pbf_directory() -> Path:
    pbf_directory = get_map_directory() / 'pbf'
    if not pbf_directory.is_dir():
        pbf_directory.mkdir(parents=True)
    return pbf_directory


def is_pbf_file(pbf: Path) -> bool:
    """Uses file command to check type of a file.  Returns True if a file is an OpenStreetMap PBF file."""
    cmd = ('/usr/bin/file', pbf)
    try:
        output = subprocess.check_output(cmd)
    except FileNotFoundError:
        return False

    return 'OpenStreetMap Protocolbuffer Binary Format' in output.decode()


def get_pbf_paths() -> List[Path]:
    """Find all PBF files in the map/pbf directory"""
    pbf_directory = get_pbf_directory()
    paths = walk(pbf_directory)
    return list(filter(lambda i: i.is_file() and str(i).endswith('.osm.pbf') and is_pbf_file(i), paths))


def get_or_create_map_file(pbf_path: Path, session: Session) -> MapFile:
    """Finds the MapFile row in the DB, or creates one."""
    map_file: MapFile = session.query(MapFile).filter_by(path=str(pbf_path)).one_or_none()
    if map_file:
        return map_file

    map_file = MapFile(path=pbf_path, size=pbf_path.stat().st_size)
    session.add(map_file)
    return map_file


async def import_pbfs(pbfs: List[str]):
    if IMPORT_EVENT.is_set():
        logger.warning('Map import already running...')
        return

    logger.warning(f'Importing: {", ".join(pbfs)}')

    any_success = False
    try:
        IMPORT_EVENT.set()
        for pbf in pbfs:
            pbf = get_media_directory() / pbf
            if not pbf.is_file():
                logger.fatal(f'PBF file does not exist! {pbf}')
                continue

            with get_db_session() as session:
                map_file = session.query(MapFile).filter_by(path=pbf).one_or_none()
                if map_file and map_file.imported:
                    # Don't import a map file twice.
                    logger.debug(f'{pbf} is already imported')
                    continue

            success = False
            try:
                IMPORTING['pbf'] = str(pbf)
                await import_pbf(pbf)
                success = True
                any_success = True
            except Exception as e:
                logger.warning('Failed to run import_pbf', exc_info=e)
            finally:
                IMPORTING['pbf'] = None

            if success:
                with get_db_session(commit=True) as session:
                    map_file = get_or_create_map_file(pbf, session)
                    map_file.imported = True
    finally:
        if any_success:
            # A map was imported, remove the tile cache files.
            clear_mod_tile()
        IMPORT_EVENT.clear()


BASH = which('bash', '/bin/bash', warn=True)


async def import_pbf(pbf: Path):
    """Run the osm2pgsql binary to import a PBF map file."""
    cmd = f'{BASH} {PROJECT_DIR}/scripts/import_map.sh {pbf.absolute()}'
    logger.debug(f'Running import script: {cmd}')
    start = now()
    proc = await asyncio.create_subprocess_shell(cmd, stderr=asyncio.subprocess.PIPE, stdout=asyncio.subprocess.PIPE)

    stdout, stderr = await proc.communicate()
    elapsed = now() - start
    success = 'Successful' if proc.returncode == 0 else 'Unsuccessful'
    logger.info(f'{success} import of {pbf.name} took {timedelta_to_timestamp(elapsed)}')
    if proc.returncode != 0:
        # Log all lines.  Truncate long lines.
        for line in stdout.decode().splitlines():
            logger.debug(line[:500])
        for line in stderr.decode().splitlines():
            logger.error(line[:500])
        raise ValueError(f'Importing PBF failed with return code {proc.returncode}')


@optional_session
def get_pbf_import_status(session: Session = None):
    pbf_paths: List[Path] = get_pbf_paths()

    pbfs = []
    for path in pbf_paths:
        map_file = get_or_create_map_file(path, session)
        pbfs.append(map_file)
    session.commit()
    return pbfs


MOD_TILE_CACHE_DIR = Path('/var/lib/mod_tile/ajt')


@wrol_mode_check
def clear_mod_tile():
    """Remove all cached map tile files"""
    if PYTEST:
        return

    logger.warning('Clearing map tile cache files')

    if MOD_TILE_CACHE_DIR.is_dir():
        cmd = ('rm', '-r', MOD_TILE_CACHE_DIR)
        subprocess.check_call(cmd)