import hashlib
import os
import tempfile
import zipfile
from datetime import datetime, timedelta
from typing import Dict, List, Optional, Tuple, Union
from uuid import UUID

import gpxpy.gpx
import pytz
from flask import current_app
from sqlalchemy import exc
from staticmap import Line, StaticMap
from werkzeug.datastructures import FileStorage
from werkzeug.utils import secure_filename

from fittrackee import db
from fittrackee.users.models import User

from .exceptions import WorkoutException
from .models import Sport, Workout, WorkoutSegment
from .utils_files import get_absolute_file_path
from .utils_gpx import get_gpx_info


def get_datetime_with_tz(
    timezone: str, workout_date: datetime, gpx_data: Optional[Dict] = None
) -> Tuple[Optional[datetime], datetime]:
    """
    Return naive datetime and datetime with user timezone
    """
    workout_date_tz = None
    if timezone:
        user_tz = pytz.timezone(timezone)
        utc_tz = pytz.utc
        if gpx_data:
            # workout date in gpx is in UTC, but in naive datetime
            fmt = '%Y-%m-%d %H:%M:%S'
            workout_date_string = workout_date.strftime(fmt)
            workout_date_tmp = utc_tz.localize(
                datetime.strptime(workout_date_string, fmt)
            )
            workout_date_tz = workout_date_tmp.astimezone(user_tz)
        else:
            workout_date_tz = user_tz.localize(workout_date)
            workout_date = workout_date_tz.astimezone(utc_tz)
            # make datetime 'naive' like in gpx file
            workout_date = workout_date.replace(tzinfo=None)

    return workout_date_tz, workout_date


def update_workout_data(
    workout: Union[Workout, WorkoutSegment], gpx_data: Dict
) -> Union[Workout, WorkoutSegment]:
    """
    Update workout or workout segment with data from gpx file
    """
    workout.pauses = gpx_data['stop_time']
    workout.moving = gpx_data['moving_time']
    workout.min_alt = gpx_data['elevation_min']
    workout.max_alt = gpx_data['elevation_max']
    workout.descent = gpx_data['downhill']
    workout.ascent = gpx_data['uphill']
    workout.max_speed = gpx_data['max_speed']
    workout.ave_speed = gpx_data['average_speed']
    return workout


def create_workout(
    user: User, workout_data: Dict, gpx_data: Optional[Dict] = None
) -> Workout:
    """
    Create Workout from data entered by user and from gpx if a gpx file is
    provided
    """
    workout_date = (
        gpx_data['start']
        if gpx_data
        else datetime.strptime(workout_data['workout_date'], '%Y-%m-%d %H:%M')
    )
    workout_date_tz, workout_date = get_datetime_with_tz(
        user.timezone, workout_date, gpx_data
    )

    duration = (
        gpx_data['duration']
        if gpx_data
        else timedelta(seconds=workout_data['duration'])
    )
    distance = gpx_data['distance'] if gpx_data else workout_data['distance']
    title = gpx_data['name'] if gpx_data else workout_data.get('title', '')

    new_workout = Workout(
        user_id=user.id,
        sport_id=workout_data['sport_id'],
        workout_date=workout_date,
        distance=distance,
        duration=duration,
    )
    new_workout.notes = workout_data.get('notes')

    if title is not None and title != '':
        new_workout.title = title
    else:
        sport = Sport.query.filter_by(id=new_workout.sport_id).first()
        fmt = "%Y-%m-%d %H:%M:%S"
        workout_datetime = (
            workout_date_tz.strftime(fmt)
            if workout_date_tz
            else new_workout.workout_date.strftime(fmt)
        )
        new_workout.title = f'{sport.label} - {workout_datetime}'

    if gpx_data:
        new_workout.gpx = gpx_data['filename']
        new_workout.bounds = gpx_data['bounds']
        update_workout_data(new_workout, gpx_data)
    else:
        new_workout.moving = duration
        new_workout.ave_speed = (
            None
            if duration.seconds == 0
            else float(new_workout.distance) / (duration.seconds / 3600)
        )
        new_workout.max_speed = new_workout.ave_speed
    return new_workout


def create_segment(
    workout_id: int, workout_uuid: UUID, segment_data: Dict
) -> WorkoutSegment:
    """
    Create Workout Segment from gpx data
    """
    new_segment = WorkoutSegment(
        workout_id=workout_id,
        workout_uuid=workout_uuid,
        segment_id=segment_data['idx'],
    )
    new_segment.duration = segment_data['duration']
    new_segment.distance = segment_data['distance']
    update_workout_data(new_segment, segment_data)
    return new_segment


def update_workout(workout: Workout) -> Workout:
    """
    Update workout data from gpx file
    """
    gpx_data, _, _ = get_gpx_info(
        get_absolute_file_path(workout.gpx), False, False
    )
    updated_workout = update_workout_data(workout, gpx_data)
    updated_workout.duration = gpx_data['duration']
    updated_workout.distance = gpx_data['distance']
    db.session.flush()

    for segment_idx, segment in enumerate(updated_workout.segments):
        segment_data = gpx_data['segments'][segment_idx]
        updated_segment = update_workout_data(segment, segment_data)
        updated_segment.duration = segment_data['duration']
        updated_segment.distance = segment_data['distance']
        db.session.flush()

    return updated_workout


def edit_workout(
    workout: Workout, workout_data: Dict, auth_user_id: int
) -> Workout:
    """
    Edit an workout
    Note: the gpx file is NOT modified

    In a next version, map_data and weather_data will be updated
    (case of a modified gpx file, see issue #7)
    """
    user = User.query.filter_by(id=auth_user_id).first()
    if workout_data.get('refresh'):
        workout = update_workout(workout)
    if workout_data.get('sport_id'):
        workout.sport_id = workout_data.get('sport_id')
    if workout_data.get('title'):
        workout.title = workout_data.get('title')
    if workout_data.get('notes'):
        workout.notes = workout_data.get('notes')
    if not workout.gpx:
        if workout_data.get('workout_date'):
            workout_date = datetime.strptime(
                workout_data['workout_date'], '%Y-%m-%d %H:%M'
            )
            _, workout.workout_date = get_datetime_with_tz(
                user.timezone, workout_date
            )

        if workout_data.get('duration'):
            workout.duration = timedelta(seconds=workout_data['duration'])
            workout.moving = workout.duration

        if workout_data.get('distance'):
            workout.distance = workout_data['distance']

        workout.ave_speed = (
            None
            if workout.duration.seconds == 0
            else float(workout.distance) / (workout.duration.seconds / 3600)
        )
        workout.max_speed = workout.ave_speed
    return workout


def get_file_path(dir_path: str, filename: str) -> str:
    """
    Get full path for a file
    """
    if not os.path.exists(dir_path):
        os.makedirs(dir_path)
    file_path = os.path.join(dir_path, filename)
    return file_path


def get_new_file_path(
    auth_user_id: int,
    workout_date: str,
    sport: str,
    old_filename: Optional[str] = None,
    extension: Optional[str] = None,
) -> str:
    """
    Generate a file path from user and workout data
    """
    if not extension and old_filename:
        extension = f".{old_filename.rsplit('.', 1)[1].lower()}"
    _, new_filename = tempfile.mkstemp(
        prefix=f'{workout_date}_{sport}_', suffix=extension
    )
    dir_path = os.path.join('workouts', str(auth_user_id))
    if not os.path.exists(dir_path):
        os.makedirs(dir_path)
    file_path = os.path.join(dir_path, new_filename.split('/')[-1])
    return file_path


def generate_map(map_filepath: str, map_data: List) -> None:
    """
    Generate and save map image from map data
    """
    m = StaticMap(400, 225, 10)
    line = Line(map_data, '#3388FF', 4)
    m.add_line(line)
    image = m.render()
    image.save(map_filepath)


def get_map_hash(map_filepath: str) -> str:
    """
    Generate a md5 hash used as id instead of workout id, to retrieve map
    image (maps are sensitive data)
    """
    md5 = hashlib.md5()
    absolute_map_filepath = get_absolute_file_path(map_filepath)
    with open(absolute_map_filepath, 'rb') as f:
        for chunk in iter(lambda: f.read(128 * md5.block_size), b''):
            md5.update(chunk)
    return md5.hexdigest()


def process_one_gpx_file(params: Dict, filename: str) -> Workout:
    """
    Get all data from a gpx file to create an workout with map image
    """
    try:
        gpx_data, map_data, weather_data = get_gpx_info(params['file_path'])
        auth_user_id = params['user'].id
        new_filepath = get_new_file_path(
            auth_user_id=auth_user_id,
            workout_date=gpx_data['start'],
            old_filename=filename,
            sport=params['sport_label'],
        )
        absolute_gpx_filepath = get_absolute_file_path(new_filepath)
        os.rename(params['file_path'], absolute_gpx_filepath)
        gpx_data['filename'] = new_filepath

        map_filepath = get_new_file_path(
            auth_user_id=auth_user_id,
            workout_date=gpx_data['start'],
            extension='.png',
            sport=params['sport_label'],
        )
        absolute_map_filepath = get_absolute_file_path(map_filepath)
        generate_map(absolute_map_filepath, map_data)
    except (gpxpy.gpx.GPXXMLSyntaxException, TypeError) as e:
        raise WorkoutException('error', 'Error during gpx file parsing.', e)
    except Exception as e:
        raise WorkoutException('error', 'Error during gpx processing.', e)

    try:
        new_workout = create_workout(
            params['user'], params['workout_data'], gpx_data
        )
        new_workout.map = map_filepath
        new_workout.map_id = get_map_hash(map_filepath)
        new_workout.weather_start = weather_data[0]
        new_workout.weather_end = weather_data[1]
        db.session.add(new_workout)
        db.session.flush()

        for segment_data in gpx_data['segments']:
            new_segment = create_segment(
                new_workout.id, new_workout.uuid, segment_data
            )
            db.session.add(new_segment)
        db.session.commit()
        return new_workout
    except (exc.IntegrityError, ValueError) as e:
        raise WorkoutException('fail', 'Error during workout save.', e)


def process_zip_archive(common_params: Dict, extract_dir: str) -> List:
    """
    Get files from a zip archive and create workouts, if number of files
    does not exceed defined limit.
    """
    with zipfile.ZipFile(common_params['file_path'], "r") as zip_ref:
        zip_ref.extractall(extract_dir)

    new_workouts = []
    gpx_files_limit = current_app.config['gpx_limit_import']
    gpx_files_ok = 0

    for gpx_file in os.listdir(extract_dir):
        if (
            '.' in gpx_file
            and gpx_file.rsplit('.', 1)[1].lower()
            in current_app.config['WORKOUT_ALLOWED_EXTENSIONS']
        ):
            gpx_files_ok += 1
            if gpx_files_ok > gpx_files_limit:
                break
            file_path = os.path.join(extract_dir, gpx_file)
            params = common_params
            params['file_path'] = file_path
            new_workout = process_one_gpx_file(params, gpx_file)
            new_workouts.append(new_workout)

    return new_workouts


def process_files(
    auth_user_id: int,
    workout_data: Dict,
    workout_file: FileStorage,
    folders: Dict,
) -> List:
    """
    Store gpx file or zip archive and create workouts
    """
    if workout_file.filename is None:
        raise WorkoutException('error', 'File has no filename.')
    filename = secure_filename(workout_file.filename)
    extension = f".{filename.rsplit('.', 1)[1].lower()}"
    file_path = get_file_path(folders['tmp_dir'], filename)
    sport = Sport.query.filter_by(id=workout_data.get('sport_id')).first()
    if not sport:
        raise WorkoutException(
            'error',
            f"Sport id: {workout_data.get('sport_id')} does not exist",
        )
    user = User.query.filter_by(id=auth_user_id).first()

    common_params = {
        'user': user,
        'workout_data': workout_data,
        'file_path': file_path,
        'sport_label': sport.label,
    }

    try:
        workout_file.save(file_path)
    except Exception as e:
        raise WorkoutException('error', 'Error during workout file save.', e)

    if extension == ".gpx":
        return [process_one_gpx_file(common_params, filename)]
    else:
        return process_zip_archive(common_params, folders['extract_dir'])


def get_upload_dir_size() -> int:
    """
    Return upload directory size
    """
    upload_path = get_absolute_file_path('')
    total_size = 0
    for dir_path, _, filenames in os.walk(upload_path):
        for f in filenames:
            fp = os.path.join(dir_path, f)
            total_size += os.path.getsize(fp)
    return total_size