"""Generate and upload JSON metadata files for public datasets on GCS."""

import json
import logging
import os
import re
from argparse import ArgumentParser
from itertools import groupby

import smart_open
from google.cloud import storage  # type: ignore

from bigquery_etl.config import ConfigLoader
from bigquery_etl.metadata.parse_metadata import Metadata
from bigquery_etl.util import standard_args
from bigquery_etl.util.common import project_dirs

GCS_FILE_PATH_RE = re.compile(
    r"api/(?P<api_version>.+)/tables/(?P<dataset>.+)/(?P<table>.+)/(?P<version>.+)/"
    r"files/(?:(?P<date>.+)/)?(?P<filename>.+\.json(\.gz)?)"
)

parser = ArgumentParser(description=__doc__)
parser.add_argument(
    "--project_id", "--project-id", default="mozilla-public-data", help="Target project"
)
parser.add_argument(
    "--target-bucket",
    "--target_bucket",
    default=ConfigLoader.get(
        "public_data", "bucket", fallback="mozilla-public-data-http"
    ),
    help="GCP bucket JSON data is exported to",
)
parser.add_argument(
    "--endpoint",
    default=ConfigLoader.get(
        "public_data", "endpoint", fallback="https://public-data.telemetry.mozilla.org/"
    ),
    help="The URL to access the HTTP endpoint",
)
parser.add_argument(
    "--api_version",
    "--api-version",
    default=ConfigLoader.get("public_data", "api_version", fallback="v1"),
    help="Endpoint API version",
)
standard_args.add_log_level(parser)


class GcsTableMetadata:
    """Metadata associated with table data stored on GCS."""

    def __init__(self, blobs, endpoint, target_dir):
        """Initialize container for metadata of a table published on GCS."""
        assert len(blobs) > 0
        self.blobs = blobs
        self.endpoint = endpoint
        self.files_path = self.blobs[0].name.split("files")[0] + "files"
        self.files_uri = endpoint + self.files_path

        (self.dataset, self.table, self.version) = dataset_table_version_from_gcs_blob(
            self.blobs[0]
        )
        self.metadata = Metadata.of_table(
            self.dataset, self.table, self.version, target_dir
        )

        self.last_updated_path = self.blobs[0].name.split("files")[0] + "last_updated"
        self.last_updated_uri = endpoint + self.last_updated_path

    def table_metadata_to_json(self):
        """Return a JSON object of the table metadata for GCS."""
        metadata_json = {}
        metadata_json["friendly_name"] = self.metadata.friendly_name
        metadata_json["description"] = self.metadata.description
        metadata_json["incremental"] = self.metadata.is_incremental()
        metadata_json["incremental_export"] = self.metadata.is_incremental_export()

        if self.metadata.review_bugs() is not None:
            review_links = list(
                map(
                    lambda bug: ConfigLoader.get(
                        "public_data",
                        "review_link",
                        fallback="https://bugzilla.mozilla.org/show_bug.cgi?id=",
                    )
                    + str(bug),
                    self.metadata.review_bugs(),
                )
            )
            metadata_json["review_links"] = review_links

        metadata_json["files_uri"] = self.files_uri
        metadata_json["last_updated"] = self.last_updated_uri

        return metadata_json

    def files_metadata_to_json(self):
        """Return a JSON object containing metadata of the files on GCS."""
        if self.metadata.is_incremental_export():
            metadata_json = {}

            for blob in self.blobs:
                match = GCS_FILE_PATH_RE.match(blob.name)
                date = match.group("date")

                if date is not None:
                    if date in metadata_json:
                        metadata_json[date].append(self.endpoint + blob.name)
                    else:
                        metadata_json[date] = [self.endpoint + blob.name]

            return metadata_json
        else:
            return [self.endpoint + blob.name for blob in self.blobs]


def dataset_table_version_from_gcs_blob(gcs_blob):
    """Extract the dataset, table and version from the provided GCS blob path."""
    match = GCS_FILE_PATH_RE.match(gcs_blob.name)

    if match is not None:
        return (match.group("dataset"), match.group("table"), match.group("version"))
    else:
        return None


def get_public_gcs_table_metadata(
    storage_client, bucket, api_version, endpoint, target_dir
):
    """Return a list of metadata of public tables and their locations on GCS."""
    prefix = f"api/{api_version}"

    blobs = storage_client.list_blobs(bucket, prefix=prefix)

    return [
        GcsTableMetadata(list(blobs), endpoint, target_dir)
        for table, blobs in groupby(blobs, dataset_table_version_from_gcs_blob)
        if table is not None
        and table[0] in os.listdir(target_dir)
        and f"{table[1]}_{table[2]}" in os.listdir(os.path.join(target_dir, table[0]))
    ]


def publish_all_datasets_metadata(table_metadata, output_file):
    """Write metadata about all available public datasets to GCS."""
    metadata_json = {}

    for metadata in table_metadata:
        if metadata.dataset not in metadata_json:
            metadata_json[metadata.dataset] = {}

        dataset = metadata_json[metadata.dataset]

        if metadata.table not in dataset:
            dataset[metadata.table] = {}

        table = dataset[metadata.table]

        if metadata.version not in table:
            table[metadata.version] = {}

        table[metadata.version] = metadata.table_metadata_to_json()

    logging.info(f"Write metadata to {output_file}")

    with smart_open.open(output_file, "w") as fout:
        fout.write(json.dumps(metadata_json, indent=4))


def publish_table_metadata(storage_client, table_metadata, bucket):
    """Write metadata for each public table to GCS."""
    for metadata in table_metadata:
        output_file = f"gs://{bucket}/{metadata.files_path}"

        logging.info(f"Write metadata to {output_file}")
        with smart_open.open(output_file, "w") as fout:
            fout.write(json.dumps(metadata.files_metadata_to_json(), indent=4))

        set_content_type(
            storage_client, bucket, f"{metadata.files_path}", "application/json"
        )


def set_content_type(storage_client, bucket, file, content_type):
    """Set the file content type."""
    blob = storage_client.get_bucket(bucket).get_blob(file)
    blob.content_type = content_type
    blob.patch()


def main():
    """Generate and upload GCS metadata."""
    args = parser.parse_args()
    storage_client = storage.Client(args.project_id)

    # set log level
    try:
        logging.basicConfig(level=args.log_level, format="%(levelname)s %(message)s")
    except ValueError as e:
        parser.error(f"argument --log-level: {e}")

    projects = project_dirs()
    all_metadata = []

    for target in projects:
        if os.path.isdir(target):
            gcs_table_metadata = get_public_gcs_table_metadata(
                storage_client,
                args.target_bucket,
                args.api_version,
                args.endpoint,
                target,
            )
            all_metadata += gcs_table_metadata
            publish_table_metadata(
                storage_client, gcs_table_metadata, args.target_bucket
            )
        else:
            print(
                f"Invalid target: {target}, target must be a directory with"
                "structure <project>/<dataset>/<table>/metadata.yaml."
            )

    output_file = f"gs://{args.target_bucket}/all-datasets.json"
    publish_all_datasets_metadata(all_metadata, output_file)
    set_content_type(
        storage_client,
        args.target_bucket,
        "all-datasets.json",
        "application/json",
    )


if __name__ == "__main__":
    main()