import hashlib
from datetime import datetime, timedelta
from urllib.parse import urlparse

import boto3
import botocore
from botocore.client import Config
from botocore.exceptions import ClientError
from decouple import config
from requests.models import PreparedRequest

if not config("S3_HOST", default=False):
    client = boto3.client('s3')
else:
    client = boto3.client('s3', endpoint_url=config("S3_HOST"),
                          aws_access_key_id=config("S3_KEY"),
                          aws_secret_access_key=config("S3_SECRET"),
                          config=Config(signature_version='s3v4'),
                          region_name=config("sessions_region"),
                          verify=not config("S3_DISABLE_SSL_VERIFY", default=False, cast=bool))


def __get_s3_resource():
    if not config("S3_HOST", default=False):
        return boto3.resource('s3')
    return boto3.resource('s3', endpoint_url=config("S3_HOST"),
                          aws_access_key_id=config("S3_KEY"),
                          aws_secret_access_key=config("S3_SECRET"),
                          config=Config(signature_version='s3v4'),
                          region_name=config("sessions_region"),
                          verify=not config("S3_DISABLE_SSL_VERIFY", default=False, cast=bool))


def exists(bucket, key):
    try:
        __get_s3_resource().Object(bucket, key).load()
    except botocore.exceptions.ClientError as e:
        if e.response['Error']['Code'] == "404":
            return False
        else:
            # Something else has gone wrong.
            raise
    return True


def get_presigned_url_for_sharing(bucket, expires_in, key, check_exists=False):
    if check_exists and not exists(bucket, key):
        return None

    return client.generate_presigned_url(
        'get_object',
        Params={
            'Bucket': bucket,
            'Key': key
        },
        ExpiresIn=expires_in
    )


def get_presigned_url_for_upload(bucket, expires_in, key, **args):
    return client.generate_presigned_url(
        'put_object',
        Params={
            'Bucket': bucket,
            'Key': key
        },
        ExpiresIn=expires_in
    )


def get_presigned_url_for_upload_secure(bucket, expires_in, key, conditions=None, public=False, content_type=None):
    acl = 'private'
    if public:
        acl = 'public-read'
    fields = {"acl": acl}
    if content_type:
        fields["Content-Type"] = content_type
    url_parts = client.generate_presigned_post(
        Bucket=bucket,
        Key=key,
        ExpiresIn=expires_in,
        Fields=fields,
        Conditions=conditions,
    )
    req = PreparedRequest()
    req.prepare_url(
        f"{url_parts['url']}/{url_parts['fields']['key']}", url_parts['fields'])
    return req.url


def get_file(source_bucket, source_key):
    try:
        result = client.get_object(
            Bucket=source_bucket,
            Key=source_key
        )
    except ClientError as ex:
        if ex.response['Error']['Code'] == 'NoSuchKey':
            return None
        else:
            raise ex
    return result["Body"].read().decode()


def rename(source_bucket, source_key, target_bucket, target_key):
    s3 = __get_s3_resource()
    s3.Object(target_bucket, target_key).copy_from(
        CopySource=f'{source_bucket}/{source_key}')
    s3.Object(source_bucket, source_key).delete()


def schedule_for_deletion(bucket, key):
    if not exists(bucket, key):
        return False
    s3 = __get_s3_resource()
    s3_object = s3.Object(bucket, key)
    s3_object.copy_from(CopySource={'Bucket': bucket, 'Key': key},
                        Expires=datetime.utcnow() + timedelta(days=config("SCH_DELETE_DAYS", cast=int, default=30)),
                        MetadataDirective='REPLACE')
    return True


def generate_file_key(project_id, key):
    return f"{project_id}/{hashlib.md5(key.encode()).hexdigest()}"


def generate_file_key_from_url(project_id, url):
    u = urlparse(url)
    new_url = u.scheme + "://" + u.netloc + u.path
    return generate_file_key(project_id=project_id, key=new_url)