import hashlib
import json
from typing import Dict, Any, List


class ReproBundle:
    """Compact, content-addressed bundle for reproducible runs.

    The bundle is a mapping of named components (code_commit, environment,
    datasets, model_refs, run_manifest). We compute a deterministic Merkle-like
    root by hashing each component's canonical JSON (sorted keys) and then
    hashing the concatenation of component hashes in a stable order.
    """

    def __init__(self, components: Dict[str, Any]):
        # Normalize components to dict of JSON-serializable structures
        self.components = components

    def _hash_component(self, name: str, value: Any) -> str:
        serialized = json.dumps({"name": name, "value": value}, sort_keys=True, default=str)
        return hashlib.sha256(serialized.encode("utf-8")).hexdigest()

    def merkle_root(self) -> str:
        # Compute per-component hashes, sort by component name to ensure order-independence
        items: List[tuple] = []
        for k, v in self.components.items():
            h = self._hash_component(k, v)
            items.append((k, h))
        items.sort(key=lambda x: x[0])
        concat = "".join(h for _, h in items).encode("utf-8")
        return hashlib.sha256(concat).hexdigest()

    def to_dict(self) -> Dict[str, Any]:
        return {"components": self.components, "merkle_root": self.merkle_root()}

    def to_json(self) -> str:
        return json.dumps(self.to_dict(), sort_keys=True, default=str)