""" Partial port of sentry/tasks/assemble.py """
from enum import Enum
import hashlib
import shutil
import tempfile
from os import path
import json
from django.core.cache import cache
from django.core.files import File
from django.db import transaction, IntegrityError
from organizations_ext.models import Organization
from releases.models import Release, ReleaseFile
from sentry.utils.zip import safe_extract_zip
from .models import File, FileBlob
from .exceptions import AssembleChecksumMismatch, AssembleArtifactsError


MAX_FILE_SIZE = 2 ** 31  # 2GB is the maximum offset supported by fileblob


class ChunkFileState(Enum):
    OK = "ok"  # File in database
    NOT_FOUND = "not_found"  # File not found in database
    CREATED = "created"  # File was created in the request and send to the worker for assembling
    ASSEMBLING = "assembling"  # File still being processed by worker
    ERROR = "error"  # Error happened during assembling


class AssembleTask(Enum):
    DIF = "project.dsym"  # Debug file upload
    ARTIFACTS = "organization.artifacts"  # Release file upload


def _get_cache_key(task, scope, checksum):
    """Computes the cache key for assemble status.

    ``task`` must be one of the ``AssembleTask`` values. The scope can be the
    identifier of any model, such as the organization or project that this task
    is performed under.

    ``checksum`` should be the SHA1 hash of the main file that is being
    assembled.
    """
    return (
        "assemble-status:%s"
        % hashlib.sha1(
            ("%s|%s|%s" % (scope, checksum.encode("ascii"), task)).encode()
        ).hexdigest()
    )


def set_assemble_status(
    task: AssembleTask, scope, checksum, state: ChunkFileState, detail=None
):
    """
    Updates the status of an assembling task. It is cached for 10 minutes.
    """
    cache_key = _get_cache_key(task, scope, checksum)
    cache.set(cache_key, (state, detail), 600)


def assemble_artifacts(organization, version, checksum, chunks):
    set_assemble_status(
        AssembleTask.ARTIFACTS, organization.pk, checksum, ChunkFileState.ASSEMBLING
    )
    # Assemble the chunks into a temporary file
    rv = assemble_file(
        AssembleTask.ARTIFACTS,
        organization,
        "release-artifacts.zip",
        checksum,
        chunks,
        file_type="release.bundle",
    )

    if rv is None:
        return

    bundle, temp_file = rv
    scratchpad = tempfile.mkdtemp()

    try:
        safe_extract_zip(temp_file, scratchpad, strip_toplevel=False)
    except BaseException as ex:
        raise AssembleArtifactsError("failed to extract bundle") from ex

    try:
        manifest_path = path.join(scratchpad, "manifest.json")
        with open(manifest_path, "rb") as manifest:
            manifest = json.loads(manifest.read())
    except BaseException as ex:
        raise AssembleArtifactsError("failed to open release manifest") from ex

    if organization.slug != manifest.get("org"):
        raise AssembleArtifactsError("organization does not match uploaded bundle")

    release_name = manifest.get("release")
    if release_name != version:
        raise AssembleArtifactsError("release does not match uploaded bundle")

    try:
        release = organization.release_set.get(version=release_name)
    except Release.DoesNotExist as ex:
        raise AssembleArtifactsError("release does not exist") from ex

    # Sentry would add dist to release here

    artifacts = manifest.get("files", {})
    for rel_path, artifact in artifacts.items():
        artifact_url = artifact.get("url", rel_path)
        artifact_basename = artifact_url.rsplit("/", 1)[-1]

        file = File.objects.create(
            name=artifact_basename,
            type="release.file",
            headers=artifact.get("headers", {}),
        )

        full_path = path.join(scratchpad, rel_path)
        with open(full_path, "rb") as fp:
            file.putfile(fp)

        kwargs = {
            "organization_id": organization.id,
            "release": release,
            "name": artifact_url,
            # "dist": dist,
        }

        release_file, created = ReleaseFile.objects.get_or_create(
            release=release, name=artifact_url, defaults={"file": file}
        )
        if not created:
            old_file = release_file.file
            release_file.file = file
            release_file.save(update_fields=["file"])
            old_file.delete()

    set_assemble_status(
        AssembleTask.ARTIFACTS, organization.pk, checksum, ChunkFileState.OK
    )
    shutil.rmtree(scratchpad)
    bundle.delete()


def assemble_file(
    task: AssembleTask,
    organization: Organization,
    name: str,
    checksum,
    chunks,
    file_type,
):
    """
    Verifies and assembles a file model from chunks.

    This downloads all chunks from blob store to verify their integrity and
    associates them with a created file model. Additionally, it assembles the
    full file in a temporary location and verifies the complete content hash.

    Returns a tuple ``(File, TempFile)`` on success, or ``None`` on error.
    """
    # Load all FileBlobs from db since we can be sure here we already own all
    # chunks need to build the file
    file_blobs = FileBlob.objects.filter(checksum__in=chunks).values_list(
        "id", "checksum", "size"
    )

    # Reject all files that exceed the maximum allowed size for this
    # organization. This value cannot be
    file_size = sum(x[2] for x in file_blobs)
    if file_size > MAX_FILE_SIZE:
        set_assemble_status(
            task,
            organization.id,
            checksum,
            ChunkFileState.ERROR,
            detail="File exceeds maximum size",
        )
        return

    # Sanity check.  In case not all blobs exist at this point we have a
    # race condition.
    if set(x[1] for x in file_blobs) != set(chunks):
        set_assemble_status(
            task,
            organization.id,
            checksum,
            ChunkFileState.ERROR,
            detail="Not all chunks available for assembling",
        )
        return

    # Ensure blobs are in the order and duplication in which they were
    # transmitted. Otherwise, we would assemble the file in the wrong order.
    ids_by_checksum = {chks: id for id, chks, _ in file_blobs}
    file_blob_ids = [ids_by_checksum[c] for c in chunks]

    file = File.objects.create(name=name, checksum=checksum, type=file_type)
    try:
        temp_file = file.assemble_from_file_blob_ids(file_blob_ids, checksum)
    except AssembleChecksumMismatch:
        file.delete()
        set_assemble_status(
            task,
            organization.id,
            checksum,
            ChunkFileState.ERROR,
            detail="Reported checksum mismatch",
        )
    else:
        file.save()
        return file, temp_file