"""Structured conversational path helpers."""

from __future__ import annotations

from dataclasses import replace

from .models import MemoryEvent, MemoryPath, MemoryPathState
from .utils import stable_digest, utc_now_iso


def create_path(path_id: str, *, event_ids: tuple[str, ...] = (), metadata: dict | None = None) -> MemoryPath:
    return MemoryPath(path_id=path_id, event_ids=event_ids, metadata=dict(metadata or {}))


def branch_path(parent: MemoryPath, path_id: str, *, event_ids: tuple[str, ...] = ()) -> MemoryPath:
    return MemoryPath(
        path_id=path_id,
        parent_path_id=parent.path_id,
        event_ids=event_ids,
        metadata={"branched_from": parent.path_id},
    )


def merge_path(path: MemoryPath, target_path_id: str) -> MemoryPath:
    return replace(path, state=MemoryPathState.MERGED, merged_into=target_path_id, updated_at=utc_now_iso())


def abandon_path(path: MemoryPath, reason: str) -> MemoryPath:
    return replace(path, state=MemoryPathState.ABANDONED, abandoned_reason=reason, updated_at=utc_now_iso())


def compact_path(path: MemoryPath, summary_node_id: str) -> MemoryPath:
    return replace(path, state=MemoryPathState.COMPACTED, compacted_summary_id=summary_node_id, updated_at=utc_now_iso())


def path_event(path: MemoryPath, kind: str, *, metadata: dict | None = None) -> MemoryEvent:
    event_id = f"path-event:{stable_digest([path.path_id, kind, path.event_ids, metadata or {}])}"
    return MemoryEvent(
        event_id=event_id,
        kind=kind,
        metadata={
            "path_id": path.path_id,
            "parent_path_id": path.parent_path_id,
            "path_state": path.state.value,
            **dict(metadata or {}),
        },
    )