"""Snippet MCP tools: record reusable functions/components for later recall.

A snippet is a Note with note_type='snippet' (see services/snippets.py). Because
snippets are ordinary embedded notes, once recorded they surface through the same
semantic search + title-first auto-inject as everything else — so a reusable
thing recorded once can be recalled before it's re-written as a one-off.

The tools wrap services/snippets.py, mirroring the note/process tools (dedup gate
on create, System association passthrough).
"""
from __future__ import annotations

from scribe.mcp._context import current_user_id
from scribe.services import dedup as dedup_svc
from scribe.services import snippets as snippets_svc
from scribe.services import systems as systems_svc


async def list_snippets(q: str = "", tag: str = "", limit: int = 50) -> dict:
    """List recorded snippets (reusable functions/components).

    Args:
        q: Free-text search across name + body (optional).
        tag: Filter to a single tag, e.g. a language like "python" (optional).
        limit: Max results (1-100).

    Returns {"snippets": [{id, title, tags, preview}], "total": int}. The title
    reads "name — when to reach for it"; open one in full with get_snippet(id).
    """
    uid = current_user_id()
    items, total = await snippets_svc.list_snippets(
        uid, q=q or None, tag=tag, limit=max(1, min(limit, 100)),
    )
    return {"snippets": items, "total": total}


async def create_snippet(
    name: str,
    code: str,
    language: str = "",
    signature: str = "",
    when_to_use: str = "",
    repo: str = "",
    path: str = "",
    symbol: str = "",
    tags: list[str] | None = None,
    project_id: int = 0,
    system_ids: list[int] | None = None,
    force: bool = False,
) -> dict:
    """Record a reusable function/component so future sessions can RECALL it
    instead of writing a fresh one-off.

    Reach for this the moment you build (or notice) something reusable: a helper,
    a hook, a component, a pattern worth repeating. Recording it once makes it
    surface automatically when a similar problem comes up later. Before writing a
    new utility, search first — a snippet may already exist.

    Args:
        name: Short name of the function/component, e.g. "useDebouncedRef".
        code: The code itself (required).
        language: Language/format, e.g. "python", "vue", "sql". Becomes a tag and
            the code-fence language.
        signature: One-line signature/interface, e.g. "debounce(fn, ms) -> fn".
        when_to_use: One line on when to reach for it — this becomes part of the
            title, so it's what a recall menu shows. Keep it sharp.
        repo/path/symbol: Canonical location of the reference implementation.
        tags: Extra plain-string tags (language + "snippet" are added for you).
        project_id: Associate with a project (0 = no project). Snippets surface
            proactively within their project; search finds them across projects.
        system_ids: Ids of the project's Systems to associate this snippet with.
        force: Bypass the near-duplicate gate (see below).

    Returns the created snippet (including a parsed `snippet` field), OR — when a
    near-duplicate snippet already exists and force is false — {"duplicate": true,
    "existing_id": ..., "message": ...} and nothing is created.
    """
    if not (name or "").strip() or not (code or "").strip():
        raise ValueError("create_snippet requires a non-empty name and code")
    uid = current_user_id()

    title = snippets_svc.compose_title(name, when_to_use)
    body = snippets_svc.compose_body(
        code=code, language=language, signature=signature,
        when_to_use=when_to_use, repo=repo, path=path, symbol=symbol,
    )
    if not force:
        dup = await dedup_svc.find_duplicate_note(
            uid, title, body, project_id=project_id or None,
            is_task=False, note_type=snippets_svc.SNIPPET_NOTE_TYPE,
        )
        if dup is not None:
            return dedup_svc.duplicate_response(dup, "snippet")

    note = await snippets_svc.create_snippet(
        uid, name=name, code=code, language=language, signature=signature,
        when_to_use=when_to_use, repo=repo, path=path, symbol=symbol,
        tags=tags, project_id=project_id or None,
    )
    if system_ids:
        await systems_svc.set_record_systems(uid, note.id, system_ids)
    data = snippets_svc.snippet_to_dict(note)
    if system_ids:
        data["systems"] = [
            s.to_dict() for s in await systems_svc.list_record_systems(uid, note.id)
        ]
    return data


async def get_snippet(snippet_id: int) -> dict:
    """Fetch a snippet by id — the full record: code, signature, location, and a
    parsed `snippet` field of its structured parts."""
    uid = current_user_id()
    note = await snippets_svc.get_snippet(uid, snippet_id)
    if note is None:
        raise ValueError(f"snippet {snippet_id} not found")
    return snippets_svc.snippet_to_dict(note)


async def update_snippet(
    snippet_id: int,
    name: str = "",
    code: str = "",
    language: str = "",
    signature: str = "",
    when_to_use: str = "",
    repo: str = "",
    path: str = "",
    symbol: str = "",
    tags: list[str] | None = None,
    project_id: int = 0,
    system_ids: list[int] | None = None,
) -> dict:
    """Update a snippet. Only provided fields change — empty strings leave that
    field unchanged; pass tags to replace the extra-tag set."""
    uid = current_user_id()

    def _n(v: str) -> str | None:
        return v if v != "" else None

    note = await snippets_svc.update_snippet(
        uid, snippet_id,
        name=_n(name), code=_n(code), language=_n(language),
        signature=_n(signature), when_to_use=_n(when_to_use),
        repo=_n(repo), path=_n(path), symbol=_n(symbol),
        tags=tags, project_id=project_id or None,
    )
    if note is None:
        raise ValueError(f"snippet {snippet_id} not found")
    if system_ids is not None:
        await systems_svc.set_record_systems(uid, snippet_id, system_ids)
    data = snippets_svc.snippet_to_dict(note)
    if system_ids is not None:
        data["systems"] = [
            s.to_dict() for s in await systems_svc.list_record_systems(uid, snippet_id)
        ]
    return data


def register(mcp) -> None:
    for fn in (list_snippets, create_snippet, get_snippet, update_snippet):
        mcp.tool(name=fn.__name__)(fn)