from __future__ import annotations

from dataclasses import dataclass
from datetime import datetime

from google.cloud import storage


@dataclass(frozen=True)
class GcsUri:
    bucket: str
    name: str


def parse_gs_uri(uri: str) -> GcsUri:
    if not uri.startswith("gs://"):
        raise ValueError(f"not a GCS URI: {uri}")
    bucket_and_name = uri.removeprefix("gs://")
    bucket, _, name = bucket_and_name.partition("/")
    if not bucket:
        raise ValueError(f"not a GCS URI: {uri}")
    return GcsUri(bucket=bucket, name=name)


def list_objects(uri: str, *, client: storage.Client | None = None) -> list[dict]:
    parsed = parse_gs_uri(uri if uri.endswith("/") else uri + "/")
    storage_client = client or storage.Client()
    blobs = storage_client.list_blobs(parsed.bucket, prefix=parsed.name)
    return [
        {
            "name": blob.name,
            "uri": f"gs://{parsed.bucket}/{blob.name}",
            "size": int(blob.size or 0),
            "updated": blob.updated.isoformat() if blob.updated else None,
            "updated_ms": int(blob.updated.timestamp() * 1000) if blob.updated else None,
        }
        for blob in blobs
        if not blob.name.endswith("/")
    ]


def upload_text(uri: str, text: str, *, content_type: str = "application/json") -> None:
    parsed = parse_gs_uri(uri)
    client = storage.Client()
    bucket = client.bucket(parsed.bucket)
    blob = bucket.blob(parsed.name)
    blob.upload_from_string(text, content_type=content_type)


def download_text(uri: str) -> str:
    parsed = parse_gs_uri(uri)
    client = storage.Client()
    return client.bucket(parsed.bucket).blob(parsed.name).download_as_text()


def list_manifest_uris(prefix_uri: str) -> list[tuple[str, datetime | None]]:
    parsed = parse_gs_uri(prefix_uri if prefix_uri.endswith("/") else prefix_uri + "/")
    client = storage.Client()
    manifests = []
    for blob in client.list_blobs(parsed.bucket, prefix=parsed.name):
        if blob.name.endswith("/manifest.json"):
            manifests.append((f"gs://{parsed.bucket}/{blob.name}", blob.updated))
    return sorted(manifests, key=lambda item: (item[1] or datetime.min, item[0]))