Cross Shard Query Scatter Gather Mock in Python

from dataclasses import dataclass
from typing import List, Dict


@dataclass
class NodeResponse:
    node_id: int
    data: Dict[str, float]


def mock_query_shard(shard_id: int, shard_data: Dict[str, float], query: str) -> NodeResponse:
    """Simulate querying a single shard, returning matches whose value > 50."""
    matches = {k: v for k, v in shard_data.items() if query in k and v > 50}
    return NodeResponse(node_id=shard_id, data=matches)


def scatter_query(shards: List[Dict[str, float]], query: str) -> List[NodeResponse]:
    """Send query to all shards (scatter phase)."""
    return [mock_query_shard(i, shard, query) for i, shard in enumerate(shards)]


def gather_results(responses: List[NodeResponse]) -> Dict[str, float]:
    """Merge all node responses (gather phase) into a single result dict."""
    merged: Dict[str, float] = {}
    for resp in responses:
        merged.update(resp.data)
    return merged


def scatter_gather_mock(shards: List[Dict[str, float]], query: str) -> Dict[str, float]:
    """Full cross-shard query: scatter → gather."""
    return gather_results(scatter_query(shards, query))


if __name__ == "__main__":
    shards = [
        {"alpha": 20, "alpine": 90, "beta": 70},
        {"alpha2": 80, "beta2": 30, "alpha3": 100},
        {"alpine2": 60, "beta3": 95},
    ]
    result = scatter_gather_mock(shards, "alpha")
    print(result)