# Copyright 2016 Amazon.com, Inc. or its affiliates. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License"). You
# may not use this file except in compliance with the License. A copy of
# the License is located at
#
# http://aws.amazon.com/apache2.0/
#
# or in the "license" file accompanying this file. This file is
# distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF
# ANY KIND, either express or implied. See the License for the specific
# language governing permissions and limitations under the License.
import copy
import math

from s3transfer.tasks import Task
from s3transfer.tasks import SubmissionTask
from s3transfer.tasks import CreateMultipartUploadTask
from s3transfer.tasks import CompleteMultipartUploadTask
from s3transfer.utils import get_callbacks
from s3transfer.utils import calculate_range_parameter
from s3transfer.utils import get_filtered_dict
from s3transfer.utils import ChunksizeAdjuster


class CopySubmissionTask(SubmissionTask):
    """Task for submitting tasks to execute a copy"""

    EXTRA_ARGS_TO_HEAD_ARGS_MAPPING = {
        'CopySourceIfMatch': 'IfMatch',
        'CopySourceIfModifiedSince': 'IfModifiedSince',
        'CopySourceIfNoneMatch': 'IfNoneMatch',
        'CopySourceIfUnmodifiedSince': 'IfUnmodifiedSince',
        'CopySourceSSECustomerKey': 'SSECustomerKey',
        'CopySourceSSECustomerAlgorithm': 'SSECustomerAlgorithm',
        'CopySourceSSECustomerKeyMD5': 'SSECustomerKeyMD5',
        'RequestPayer': 'RequestPayer'
    }

    UPLOAD_PART_COPY_ARGS = [
        'CopySourceIfMatch',
        'CopySourceIfModifiedSince',
        'CopySourceIfNoneMatch',
        'CopySourceIfUnmodifiedSince',
        'CopySourceSSECustomerKey',
        'CopySourceSSECustomerAlgorithm',
        'CopySourceSSECustomerKeyMD5',
        'SSECustomerKey',
        'SSECustomerAlgorithm',
        'SSECustomerKeyMD5',
        'RequestPayer',
    ]

    CREATE_MULTIPART_ARGS_BLACKLIST = [
        'CopySourceIfMatch',
        'CopySourceIfModifiedSince',
        'CopySourceIfNoneMatch',
        'CopySourceIfUnmodifiedSince',
        'CopySourceSSECustomerKey',
        'CopySourceSSECustomerAlgorithm',
        'CopySourceSSECustomerKeyMD5',
        'MetadataDirective'
    ]

    COMPLETE_MULTIPART_ARGS = [
        'RequestPayer'
    ]

    def _submit(self, client, config, osutil, request_executor,
                transfer_future):
        """
        :param client: The client associated with the transfer manager

        :type config: s3transfer.manager.TransferConfig
        :param config: The transfer config associated with the transfer
            manager

        :type osutil: s3transfer.utils.OSUtil
        :param osutil: The os utility associated to the transfer manager

        :type request_executor: s3transfer.futures.BoundedExecutor
        :param request_executor: The request executor associated with the
            transfer manager

        :type transfer_future: s3transfer.futures.TransferFuture
        :param transfer_future: The transfer future associated with the
            transfer request that tasks are being submitted for
        """
        # Determine the size if it was not provided
        if transfer_future.meta.size is None:
            # If a size was not provided figure out the size for the
            # user. Note that we will only use the client provided to
            # the TransferManager. If the object is outside of the region
            # of the client, they may have to provide the file size themselves
            # with a completely new client.
            call_args = transfer_future.meta.call_args
            head_object_request = \
                self._get_head_object_request_from_copy_source(
                    call_args.copy_source)
            extra_args = call_args.extra_args

            # Map any values that may be used in the head object that is
            # used in the copy object
            for param, value in extra_args.items():
                if param in self.EXTRA_ARGS_TO_HEAD_ARGS_MAPPING:
                    head_object_request[
                        self.EXTRA_ARGS_TO_HEAD_ARGS_MAPPING[param]] = value

            response = call_args.source_client.head_object(
                **head_object_request)
            transfer_future.meta.provide_transfer_size(
                response['ContentLength'])

        # If it is greater than threshold do a multipart copy, otherwise
        # do a regular copy object.
        if transfer_future.meta.size < config.multipart_threshold:
            self._submit_copy_request(
                client, config, osutil, request_executor, transfer_future)
        else:
            self._submit_multipart_request(
                client, config, osutil, request_executor, transfer_future)

    def _submit_copy_request(self, client, config, osutil, request_executor,
                             transfer_future):
        call_args = transfer_future.meta.call_args

        # Get the needed progress callbacks for the task
        progress_callbacks = get_callbacks(transfer_future, 'progress')

        # Submit the request of a single copy.
        self._transfer_coordinator.submit(
            request_executor,
            CopyObjectTask(
                transfer_coordinator=self._transfer_coordinator,
                main_kwargs={
                    'client': client,
                    'copy_source': call_args.copy_source,
                    'bucket': call_args.bucket,
                    'key': call_args.key,
                    'extra_args': call_args.extra_args,
                    'callbacks': progress_callbacks,
                    'size': transfer_future.meta.size
                },
                is_final=True
            )
        )

    def _submit_multipart_request(self, client, config, osutil,
                                  request_executor, transfer_future):
        call_args = transfer_future.meta.call_args

        # Submit the request to create a multipart upload and make sure it
        # does not include any of the arguments used for copy part.
        create_multipart_extra_args = {}
        for param, val in call_args.extra_args.items():
            if param not in self.CREATE_MULTIPART_ARGS_BLACKLIST:
                create_multipart_extra_args[param] = val

        create_multipart_future = self._transfer_coordinator.submit(
            request_executor,
            CreateMultipartUploadTask(
                transfer_coordinator=self._transfer_coordinator,
                main_kwargs={
                    'client': client,
                    'bucket': call_args.bucket,
                    'key': call_args.key,
                    'extra_args': create_multipart_extra_args,
                }
            )
        )

        # Determine how many parts are needed based on filesize and
        # desired chunksize.
        part_size = config.multipart_chunksize
        adjuster = ChunksizeAdjuster()
        part_size = adjuster.adjust_chunksize(
            part_size, transfer_future.meta.size)
        num_parts = int(
            math.ceil(transfer_future.meta.size / float(part_size)))

        # Submit requests to upload the parts of the file.
        part_futures = []
        progress_callbacks = get_callbacks(transfer_future, 'progress')

        for part_number in range(1, num_parts + 1):
            extra_part_args = self._extra_upload_part_args(
                call_args.extra_args)
            # The part number for upload part starts at 1 while the
            # range parameter starts at zero, so just subtract 1 off of
            # the part number
            extra_part_args['CopySourceRange'] = calculate_range_parameter(
                part_size, part_number-1, num_parts, transfer_future.meta.size)
            # Get the size of the part copy as well for the progress
            # callbacks.
            size = self._get_transfer_size(
                part_size, part_number-1, num_parts, transfer_future.meta.size
            )
            part_futures.append(
                self._transfer_coordinator.submit(
                    request_executor,
                    CopyPartTask(
                        transfer_coordinator=self._transfer_coordinator,
                        main_kwargs={
                            'client': client,
                            'copy_source': call_args.copy_source,
                            'bucket': call_args.bucket,
                            'key': call_args.key,
                            'part_number': part_number,
                            'extra_args': extra_part_args,
                            'callbacks': progress_callbacks,
                            'size': size
                        },
                        pending_main_kwargs={
                            'upload_id': create_multipart_future
                        }
                    )
                )
            )

        complete_multipart_extra_args = self._extra_complete_multipart_args(
            call_args.extra_args)
        # Submit the request to complete the multipart upload.
        self._transfer_coordinator.submit(
            request_executor,
            CompleteMultipartUploadTask(
                transfer_coordinator=self._transfer_coordinator,
                main_kwargs={
                    'client': client,
                    'bucket': call_args.bucket,
                    'key': call_args.key,
                    'extra_args': complete_multipart_extra_args,
                },
                pending_main_kwargs={
                    'upload_id': create_multipart_future,
                    'parts': part_futures
                },
                is_final=True
            )
        )

    def _get_head_object_request_from_copy_source(self, copy_source):
        if isinstance(copy_source, dict):
            return copy.copy(copy_source)
        else:
            raise TypeError(
                'Expecting dictionary formatted: '
                '{"Bucket": bucket_name, "Key": key} '
                'but got %s or type %s.'
                % (copy_source, type(copy_source))
            )

    def _extra_upload_part_args(self, extra_args):
        # Only the args in COPY_PART_ARGS actually need to be passed
        # onto the upload_part_copy calls.
        return get_filtered_dict(extra_args, self.UPLOAD_PART_COPY_ARGS)

    def _extra_complete_multipart_args(self, extra_args):
        return get_filtered_dict(extra_args, self.COMPLETE_MULTIPART_ARGS)

    def _get_transfer_size(self, part_size, part_index, num_parts,
                           total_transfer_size):
        if part_index == num_parts - 1:
            # The last part may be different in size then the rest of the
            # parts.
            return total_transfer_size - (part_index * part_size)
        return part_size


class CopyObjectTask(Task):
    """Task to do a nonmultipart copy"""
    def _main(self, client, copy_source, bucket, key, extra_args, callbacks,
              size):
        """
        :param client: The client to use when calling PutObject
        :param copy_source: The CopySource parameter to use
        :param bucket: The name of the bucket to copy to
        :param key: The name of the key to copy to
        :param extra_args: A dictionary of any extra arguments that may be
            used in the upload.
        :param callbacks: List of callbacks to call after copy
        :param size: The size of the transfer. This value is passed into
            the callbacks

        """
        client.copy_object(
            CopySource=copy_source, Bucket=bucket, Key=key, **extra_args)
        for callback in callbacks:
            callback(bytes_transferred=size)


class CopyPartTask(Task):
    """Task to upload a part in a multipart copy"""
    def _main(self, client, copy_source, bucket, key, upload_id, part_number,
              extra_args, callbacks, size):
        """
        :param client: The client to use when calling PutObject
        :param copy_source: The CopySource parameter to use
        :param bucket: The name of the bucket to upload to
        :param key: The name of the key to upload to
        :param upload_id: The id of the upload
        :param part_number: The number representing the part of the multipart
            upload
        :param extra_args: A dictionary of any extra arguments that may be
            used in the upload.
        :param callbacks: List of callbacks to call after copy part
        :param size: The size of the transfer. This value is passed into
            the callbacks

        :rtype: dict
        :returns: A dictionary representing a part::

            {'Etag': etag_value, 'PartNumber': part_number}

            This value can be appended to a list to be used to complete
            the multipart upload.
        """
        response = client.upload_part_copy(
            CopySource=copy_source, Bucket=bucket, Key=key,
            UploadId=upload_id, PartNumber=part_number, **extra_args)
        for callback in callbacks:
            callback(bytes_transferred=size)
        etag = response['CopyPartResult']['ETag']
        return {'ETag': etag, 'PartNumber': part_number}
