"""Note CRUD MCP tools.

Thin wrappers over services/notes.py with is_task=False. Signatures mirror
the existing fable-mcp contracts exactly so client behavior is preserved.

Sentinel conventions (inherited from existing fable-mcp tools):
  - `tag: str = ""` / `search_text: str = ""` — empty means "no filter"
  - `project_id: int = 0` — on create: orphan note (no project); on update:
    "leave unchanged" (there is no "remove from project" through this tool,
    which is a pre-existing limitation)
  - `title: str = ""` / `body: str = ""` on update — empty means "leave unchanged"
  - `tags: list[str] | None = None` — None means "leave unchanged"; [] clears
"""
from __future__ import annotations

from scribe.mcp._context import current_user_id
from scribe.mcp.tools import systems as systems_tools
from scribe.services import access as access_svc
from scribe.services import dedup as dedup_svc
from scribe.services import notes as notes_svc
from scribe.services import supersession as supersession_svc
from scribe.services import systems as systems_svc
from scribe.services import trash as trash_svc
from scribe.services.note_usage import record_pulled


async def list_notes(
    limit: int = 20,
    offset: int = 0,
    tag: str = "",
    search_text: str = "",
    project_id: int = 0,
) -> dict:
    """List notes (non-task documents) stored in Scribe.

    Optionally filter by a single tag (plain string, no # prefix) or by
    `search_text`, which matches on MEANING — the same semantic match every
    search surface uses (#2462; keyword ILIKE is only the fallback when the
    embedder is down). With `search_text`, results order by relevance; without
    it, by last-updated descending. Reaches your records plus shared-project
    records, like every other list.

    Prefer `search` for a pure lookup — it returns scores and reaches
    everything readable; this adds the lifecycle filters on top.

    Args:
        project_id: Scope to one project. PASS THE ACTIVE PROJECT'S ID whenever a
            project is in scope so you list that project's notes, not every
            project's. 0 = no filter (all projects — use only for a deliberate
            cross-project view).
    """
    uid = current_user_id()
    rows, total = await notes_svc.list_notes(
        uid,
        q=search_text or None,
        tags=[tag] if tag else None,
        is_task=False,
        project_id=project_id or None,
        limit=max(1, min(limit, 100)),
        offset=max(0, offset),
    )
    return {"notes": [n.to_dict() for n in rows], "total": total}


async def _attach_supersession(uid: int, note_id: int, data: dict) -> None:
    """Add both directions of the supersession relation to a note payload.

    Both, because they answer different questions and only one of them is
    obvious. `supersedes` is what the author claimed. `superseded_by` is what a
    READER needs and what the note itself cannot know — a stale record handed
    over without that marker gets acted on confidently, which is worse than
    never surfacing it.

    Omitted entirely when empty, so an ordinary note's payload doesn't grow two
    permanently-empty lists. A field that always says nothing trains readers to
    skip fields, which is the lesson `consolidated_at` cost us (#2483).
    """
    rel = await supersession_svc.get_relations(uid, note_id)
    if rel["supersedes"]:
        data["supersedes"] = rel["supersedes"]
    if rel["superseded_by"]:
        data["superseded_by"] = rel["superseded_by"]
        data["superseded_note"] = (
            "A later note claims to bring this up to date — see superseded_by. "
            "Read this as what was true when written, and check the newer one "
            "before acting on it."
        )


async def get_note(note_id: int) -> dict:
    """Fetch the full content of a single Scribe note by its ID.

    Returns id, title, body (markdown), tags, project_id, created_at,
    updated_at — plus `systems` (the areas this note is filed under) or, for
    an untagged project note, the `systems_hint` question.
    A note another user shared with you also carries `shared`, `owner` and
    `permission` — read it as their suggestion, not as settled practice you set.

    IF THE RESULT CARRIES `superseded_by`, a later note claims to have brought
    this one up to date. It is still here and still readable — supersession
    demotes, it never hides — but read it as what was true when written, and
    open the newer note before acting on it.
    """
    uid = current_user_id()
    loaded = await notes_svc.get_note_for_user(uid, note_id)
    note = loaded[0] if loaded else None
    if note is None or note.deleted_at is not None:
        raise ValueError(f"note {note_id} not found")
    out = note.to_dict()
    out.update(await access_svc.describe_provenance(uid, note))
    # Records the pull for ANY note kind, not just snippets: the auto-inject
    # menu surfaces notes, tasks and processes too, so restricting this to
    # snippets would leave those permanently at zero pulls and make them look
    # like dead weight next to snippets that merely had a counter (#2085).
    record_pulled(user_id=uid, note_id=int(note.id), source="mcp_get_note")
    await _attach_supersession(uid, note_id, out)
    await systems_tools.attach_systems(
        uid, getattr(note, "user_id", uid) or uid, out, note.id, note.project_id
    )
    return out


async def create_note(
    title: str,
    body: str = "",
    tags: list[str] | None = None,
    project_id: int = 0,
    system_ids: list[int] | None = None,
    supersedes: list[int] | None = None,
    force: bool = False,
) -> dict:
    """Create a new note in Scribe.

    Args:
        title: Note title (required).
        body: Markdown content. Supports [[wikilinks]] to other notes by title.
        tags: List of plain-string tags without # prefix, e.g. ["python", "ideas"].
        project_id: Associate with a project (use 0 for no project / orphan note).
        system_ids: Ids of the project's Systems to associate this note with
            (e.g. research about a subsystem). See list_systems / create_system.
        supersedes: Ids of EARLIER notes this one replaces or brings up to date.
            Reach for it whenever you write something that overtakes what an
            older note recorded — a re-measurement, a decision that reverses an
            earlier one, a dev-log covering ground a previous one covered.
            The older note stays readable and keeps its place in search; it
            simply stops competing with this one for the same question, and
            arrives labelled when it does surface. This records a CLAIM, not a
            verdict: it never says the older note was wrong, only that it is no
            longer the current answer.
        force: Bypass the near-duplicate gate. By default, if a title- or
            meaning-similar note already exists in the same project, creation is
            BLOCKED and the existing note's id is returned so you update it
            instead (no duplicate bloat / no stale RAG copies). Set true only
            when you're sure this is a genuinely distinct note.

    Returns the created note object including its assigned id, OR — when a
    near-duplicate is found and force is false — {"duplicate": true,
    "existing_id": ..., "message": ...} and nothing is created. A tagged
    record shows its `systems`; created untagged in a project, the response
    carries the `systems_hint` question instead — answer it: tag the record,
    create the missing System, or deliberately leave it untagged.
    """
    uid = current_user_id()
    if not force:
        dup = await dedup_svc.find_duplicate_note(
            uid, title, body, project_id=project_id or None,
            is_task=False, note_type="note",
        )
        if dup is not None:
            return dedup_svc.duplicate_response(dup, "note")
    note = await notes_svc.create_note(
        uid,
        title=title,
        body=body,
        tags=tags,
        project_id=project_id or None,
    )
    if system_ids:
        await systems_svc.set_record_systems(uid, note.id, system_ids)
    if supersedes:
        try:
            await supersession_svc.set_supersedes(uid, note.id, supersedes)
        except PermissionError as exc:
            # The note WAS created — surface the real reason rather than a
            # not-found, and leave the note rather than silently rolling it back.
            raise ValueError(str(exc)) from exc
    data = note.to_dict()
    await systems_tools.attach_systems(uid, uid, data, note.id, project_id or None)
    await _attach_supersession(uid, note.id, data)
    return data


async def update_note(
    note_id: int,
    title: str = "",
    body: str = "",
    tags: list[str] | None = None,
    project_id: int = 0,
    system_ids: list[int] | None = None,
    supersedes: list[int] | None = None,
) -> dict:
    """Update an existing Scribe note. Only explicitly provided fields are changed.

    Args:
        note_id: ID of the note to update.
        title: New title, or omit to leave unchanged.
        body: New markdown body, or omit to leave unchanged.
        tags: Replaces the full tag list. Pass [] to clear all tags. Omit to leave unchanged.
        project_id: New project association. Omit (or pass 0) to leave unchanged.
        system_ids: Replace this note's System associations with these ids
            (set-semantics). None = leave unchanged; [] = clear all.
        supersedes: Replace the ids of earlier notes this one replaces
            (set-semantics). None = leave unchanged; [] = clear all. See
            create_note for when to reach for it.
    """
    uid = current_user_id()
    fields: dict = {}
    if title:
        fields["title"] = title
    if body:
        fields["body"] = body
    if tags is not None:
        fields["tags"] = tags
    if project_id:
        fields["project_id"] = project_id
    note = await notes_svc.update_note(uid, note_id, **fields)
    if note is None:
        raise ValueError(f"note {note_id} not found")
    if system_ids is not None:
        await systems_svc.set_record_systems(uid, note_id, system_ids)
    if supersedes is not None:
        try:
            await supersession_svc.set_supersedes(uid, note_id, supersedes)
        except PermissionError as exc:
            raise ValueError(str(exc)) from exc
    data = note.to_dict()
    await systems_tools.attach_systems(
        uid, getattr(note, "user_id", uid) or uid, data, note_id, note.project_id
    )
    await _attach_supersession(uid, note_id, data)
    return data


async def find_duplicate_records(kind: str = "note", threshold: float = 0.0) -> dict:
    """Notes or tasks already recorded that closely resemble each other.

    The create gate PREVENTS a duplicate arriving through an agent; the web UI
    deliberately has no gate (a human mid-thought must not be blocked by a 409),
    which makes YOU the corrections system — and a corrector has to be able to
    SEE what needs correcting. This is the finder. Run it when tidying a
    project's records, or when you suspect the same ground was covered twice.

    Args:
        kind: "note" (documents) or "task". Snippets have their own report,
            find_duplicate_snippets, whose groups propose a lossless merge.
        threshold: Similarity floor, 0-1. 0 uses the configured setting.

    READ THE `suggestion` FIELD BEFORE ACTING, because the right fix differs by
    what the records ARE, not how alike they score. For notes: a correction
    pair → declare `supersedes` on the newer; state smeared across dated
    records → extract it into the System's reference note and leave these as
    history; genuinely parallel records → leave them alone. NEVER merge notes.
    Each group carries `members` with dates and any `existing_supersessions`
    already declared inside it — a pair someone has ruled on is not an open
    question.
    """
    uid = current_user_id()
    if kind not in ("note", "task"):
        raise ValueError('kind must be "note" or "task" — snippets have their '
                         "own report, find_duplicate_snippets")
    return await dedup_svc.find_duplicate_records(
        uid, kind=kind, threshold=threshold if threshold > 0 else None,
    )


async def delete_note(note_id: int) -> dict:
    """Move a Scribe note to the trash (recoverable). Restore via restore(batch_id)."""
    uid = current_user_id()
    batch = await trash_svc.delete(uid, "note", note_id)
    if batch is None:
        raise ValueError(f"note {note_id} not found")
    return {"deleted_batch_id": batch,
            "message": f"Note {note_id} moved to trash. Restore with restore('{batch}')."}


def register(mcp) -> None:
    for fn in (
        list_notes,
        get_note,
        create_note,
        update_note,
        find_duplicate_records,
        delete_note,
    ):
        mcp.tool(name=fn.__name__)(fn)