# Copyright (C) 2019 Apple Inc. All rights reserved.
#
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# modification, are permitted provided that the following conditions
# are met:
# 1.  Redistributions of source code must retain the above copyright
#     notice, this list of conditions and the following disclaimer.
# 2.  Redistributions in binary form must reproduce the above copyright
#     notice, this list of conditions and the following disclaimer in the
#     documentation and/or other materials provided with the distribution.
#
# THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS "AS IS" AND
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# WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
# DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS BE LIABLE FOR
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# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

import calendar
import hashlib
import io
import json
import time
import zipfile

from cassandra.cqlengine import columns
from cassandra.cqlengine.models import Model
from collections import OrderedDict
from datetime import datetime
from resultsdbpy.controller.commit import Commit
from resultsdbpy.controller.configuration import Configuration
from resultsdbpy.model.commit_context import CommitContext
from resultsdbpy.model.configuration_context import ClusteredByConfiguration
from resultsdbpy.model.upload_context import UploadContext


def _get_time(input_time):
    if isinstance(input_time, datetime):
        return calendar.timegm(input_time.timetumple())
    if input_time:
        return int(input_time)
    return None


class ArchiveContext(object):
    DEFAULT_LIMIT = 10
    CHUNK_SIZE = 10 * 1024 * 1024  # Cassandra doesn't do well with data blobs of more than 10 MB
    MEMORY_LIMIT = 2 * 1024 * 1024 * 1024  # Don't allow more than 2 gigs of archives in memory at one time

    class ArchiveMetaDataByCommit(ClusteredByConfiguration):
        __table_name__ = 'archive_metadata_by_commit'
        suite = columns.Text(partition_key=True, required=True)
        branch = columns.Text(partition_key=True, required=True)
        uuid = columns.BigInt(primary_key=True, required=True, clustering_order='DESC')
        sdk = columns.Text(primary_key=True, required=True)
        start_time = columns.BigInt(primary_key=True, required=True)
        digest = columns.Text(required=True)
        size = columns.BigInt(required=True)

        def unpack(self):
            return dict(
                uuid=self.uuid,
                start_time=self.start_time,
                digest=self.digest,
                size=self.size,
            )

    # According to https://cwiki.apache.org/confluence/display/CASSANDRA2/CassandraLimitations, we should shard
    # large data blobs.
    class ArchiveChunks(Model):
        __table_name__ = 'archive_chunks'
        digest = columns.Text(partition_key=True, required=True)
        index = columns.Integer(primary_key=True, required=True)
        chunk = columns.Blob(required=True)

    @classmethod
    def assert_zipfile(cls, archive):
        if not isinstance(archive, io.BytesIO):
            raise TypeError(f'Archive expected {io.BytesIO}, got {type(archive)} instead')
        if not zipfile.is_zipfile(archive):
            raise TypeError(f'Archive is not a zipfile')

    @classmethod
    def open_zipfile(cls, archive):
        cls.assert_zipfile(archive)
        return zipfile.ZipFile(archive, mode='r')

    def __init__(self, configuration_context, commit_context, ttl_seconds=None):
        self.configuration_context = configuration_context
        self.commit_context = commit_context
        self.cassandra = self.configuration_context.cassandra
        self.ttl_seconds = ttl_seconds

        with self:
            self.cassandra.create_table(self.ArchiveMetaDataByCommit)
            self.cassandra.create_table(self.ArchiveChunks)
            self.cassandra.create_table(UploadContext.SuitesByConfiguration)

    def __enter__(self):
        self.configuration_context.__enter__()
        self.commit_context.__enter__()

    def __exit__(self, *args, **kwargs):
        self.commit_context.__exit__(*args, **kwargs)
        self.configuration_context.__exit__(*args, **kwargs)

    def register(self, archive, configuration, commits, suite, timestamp=None):
        self.assert_zipfile(archive)
        timestamp = _get_time(timestamp) or time.time()

        with self:
            uuid = self.commit_context.uuid_for_commits(commits)
            ttl = int((uuid // Commit.TIMESTAMP_TO_UUID_MULTIPLIER) + self.ttl_seconds - time.time()) if self.ttl_seconds else None

            for branch in self.commit_context.branch_keys_for_commits(commits):
                self.configuration_context.register_configuration(configuration, branch=branch, timestamp=timestamp)

                self.configuration_context.insert_row_with_configuration(
                    UploadContext.SuitesByConfiguration.__table_name__, configuration, suite=suite, branch=branch, ttl=ttl,
                )

                # Breaking up the archive into chunks
                index = 0
                size = len(archive.getvalue())
                digest = hashlib.md5(archive.getvalue()).hexdigest()
                archive.seek(0)
                while size > index * self.CHUNK_SIZE:
                    self.cassandra.insert_row(
                        self.ArchiveChunks.__table_name__,
                        digest=digest, index=index,
                        chunk=archive.read(self.CHUNK_SIZE),
                    )
                    index += 1

                self.configuration_context.insert_row_with_configuration(
                    self.ArchiveMetaDataByCommit.__table_name__, configuration=configuration, suite=suite,
                    branch=branch, uuid=uuid, ttl=ttl,
                    sdk=configuration.sdk or '?', start_time=timestamp,
                    digest=digest,
                    size=size,
                )

    def find_archive(
            self, configurations=None, suite=None, recent=True,
            branch=None, begin=None, end=None,
            begin_query_time=None, end_query_time=None,
            limit=DEFAULT_LIMIT,
    ):
        if not configurations:
            configurations = []
        if not isinstance(suite, str):
            raise TypeError(f'Expected type {str}, got {type(suite)}')

        with self:
            metadata_by_config = {}
            for configuration in configurations:
                metadata_by_config.update({config: [value.unpack() for value in values] for config, values in self.configuration_context.select_from_table_with_configurations(
                    self.ArchiveMetaDataByCommit.__table_name__, configurations=[configuration], recent=recent,
                    suite=suite, sdk=configuration.sdk, branch=branch or self.commit_context.DEFAULT_BRANCH_KEY,
                    uuid__gte=CommitContext.convert_to_uuid(begin),
                    uuid__lte=CommitContext.convert_to_uuid(end, CommitContext.timestamp_to_uuid()),
                    start_time__gte=_get_time(begin_query_time), start_time__lte=_get_time(end_query_time),
                    limit=limit,
                ).items()})

            memory_used = 0
            for values in metadata_by_config.values():
                for value in values:
                    if not value.get('digest'):
                        continue

                    memory_used += value.get('size', 0)
                    if memory_used > self.MEMORY_LIMIT:
                        raise RuntimeError('Hit soft-memory cap when fetching archives, aborting')

            result = {}
            for config, values in metadata_by_config.items():
                for value in values:
                    if not value.get('digest'):
                        continue

                    rows = self.cassandra.select_from_table(
                        self.ArchiveChunks.__table_name__,
                        digest=value.get('digest'),
                        limit=1 + int(value.get('size', 0) / self.CHUNK_SIZE),
                    )
                    if len(rows) == 0:
                        continue

                    digest = hashlib.md5()
                    archive = io.BytesIO()
                    archive_size = 0
                    for row in rows:
                        archive_size += len(row.chunk)
                        digest.update(row.chunk)
                        archive.write(row.chunk)

                    if archive_size != value.get('size', 0) or value.get('digest', '') != digest.hexdigest():
                        raise RuntimeError('Failed to reconstruct archive from chunks')

                    archive.seek(0)
                    result.setdefault(config, [])
                    result[config].append(dict(
                        archive=archive,
                        uuid=value['uuid'],
                        start_time=value['start_time'],
                    ))

            return result

    @classmethod
    def _files_for_archive(cls, archive):
        master = None
        files = set()
        for item in archive.namelist():
            if item.startswith('__'):
                continue

            if not master:
                master = item
                continue

            files.add(item[len(master):])
        return master, sorted([*files])

    def ls(self, *args, **kwargs):
        candidates = self.find_archive(*args, **kwargs)
        result = {}
        for config, archives in candidates.items():
            result[config] = []
            for archive in archives:
                result[config].append(dict(
                    uuid=archive['uuid'],
                    start_time=archive['start_time'],
                    files=set(),
                ))

                with self.open_zipfile(archive['archive']) as unpacked:
                    _, result[config][-1]['files'] = self._files_for_archive(unpacked)

        return result

    def file(self, path=None, **kwargs):
        candidates = self.find_archive(**kwargs)
        result = {}
        for config, archives in candidates.items():
            result[config] = []
            for archive in archives:
                file = None

                with self.open_zipfile(archive['archive']) as unpacked:
                    master, files = self._files_for_archive(unpacked)
                    if not path:
                        file = files
                    elif path[-1] == '/':
                        file = [f[len(path):] for f in files if f.startswith(path)]
                    elif path in files:
                        file = unpacked.open(master + path).read()

                if file:
                    result[config].append(dict(
                        uuid=archive['uuid'],
                        start_time=archive['start_time'],
                        file=file,
                    ))

        return result