FabledScribe/src/scribe/mcp/tools/milestones.py

"""Milestone CRUD MCP tools — thin wrappers over services/milestones.py.

Mirrors existing fable-mcp milestone tool contracts: list/create/update. The
existing surface has no fable_get_milestone or fable_delete_milestone — kept
that way for parity.

Sentinels:
  - title="" / description="" / status="" → "leave unchanged" on update
  - order_index=-1 → "leave unchanged" on update (0 is a valid order_index)
  - status="active" default on create
"""
from __future__ import annotations

from scribe.mcp._context import current_user_id
from scribe.services import dedup as dedup_svc
from scribe.services import milestones as milestones_svc
from scribe.services import notes as notes_svc
from scribe.services import rulebooks as rulebooks_svc
from scribe.services import trash as trash_svc
from scribe.services.record_refs import refuse_guessed_ids


async def list_milestones(project_id: int) -> dict:
    """List milestones for a Scribe project, ordered by order_index.

    Returns every milestone, done ones included: id, title, description,
    status (active/done), order_index, progress (total, completed, pct,
    status_counts) and `next_step`. The plan itself is not listed:
    get_milestone(id) returns a milestone's body and its steps.

    `next_step` is the earliest step still open — {id, title, status} — or
    null when the plan has none left. Use it as it came back. "7 of 9 done"
    invites naming the open one from memory, and a remembered id reads exactly
    like a read one while being a step that closed days ago.
    """
    uid = current_user_id()
    rows = await milestones_svc.get_project_milestone_summary(uid, project_id)
    brief, _ = milestones_svc.brief_milestone_summary(rows)
    return {"milestones": brief}


async def get_milestone(milestone_id: int) -> dict:
    """Fetch a milestone (the plan container) with its step-tasks and rules.

    A milestone IS a plan: its `body` holds the design/intent, and its steps
    are the child tasks listed here. Use this to read a plan top-to-bottom —
    the body for the design, `steps` for the trackable units of work. Mirrors
    the planning context that start_planning returns (applicable rules), so the
    rules surface again on recall.

    Returns: milestone (incl. body), progress, steps (its tasks ordered by
    status then update), and applicable_rules / project_rules. Each step says
    what it is and where it stands, not its whole body — read a step in full
    with get_task(id). A plan with forty long steps is otherwise too big to
    arrive inline, and the design is in the milestone body.
    """
    uid = current_user_id()
    milestone = await milestones_svc.get_milestone(uid, milestone_id)
    if milestone is None:
        raise ValueError(f"milestone {milestone_id} not found")
    progress = await milestones_svc.get_milestone_progress(milestone_id)
    steps, _ = await notes_svc.list_notes(
        uid, is_task=True, milestone_id=milestone_id, sort="status", limit=200,
    )
    applicable = await rulebooks_svc.get_applicable_rules(
        project_id=milestone.project_id, user_id=uid,
    )
    out = milestone.to_dict()
    out.update(progress)
    return {
        "milestone": out,
        "steps": [notes_svc.brief_row(t, {milestone.id: milestone.title}) for t in steps],
        **rulebooks_svc.rules_payload(applicable, user_id=uid, source="get_milestone"),
    }


async def create_milestone(
    project_id: int,
    title: str,
    description: str = "",
    body: str = "",
    status: str = "active",
    force: bool = False,
) -> dict:
    """Create a milestone within a Scribe project.

    A milestone can serve as a plan container — put the design/intent in `body`
    and track each step as a child task (create_task(milestone_id=...)). For a
    fresh plan, prefer start_planning, which seeds the body template + surfaces
    the project's rules.

    Args:
        project_id: The project this milestone belongs to (required).
        title: Milestone name (required).
        description: Optional one-line summary of what this milestone covers.
        body: Optional plan/design (markdown) — the milestone's full plan text.
        status: active (default) or done.
        force: Bypass the plan gate. By default an active milestone that
            already has this title, or reads as the same plan, is returned
            (`existing_milestone`) and nothing is created.
    """
    uid = current_user_id()
    await refuse_guessed_ids(title, description, body)
    # A done milestone is a record of past work, not a competing plan, so
    # only an active create is gated — the same line find_matching_plan draws.
    if status == "active" and not force:
        match = await dedup_svc.plan_gate(
            uid, project_id, title,
            dedup_svc.plan_candidate_text(description=description, body=body),
        )
        if match is not None:
            return match
    milestone = await milestones_svc.create_milestone(
        uid,
        project_id=project_id,
        title=title,
        description=description or None,
        body=body or None,
        status=status,
    )
    return milestone.to_dict()


async def update_milestone(
    project_id: int,
    milestone_id: int,
    title: str = "",
    description: str = "",
    body: str = "",
    status: str = "",
    order_index: int = -1,
) -> dict:
    """Update a Scribe milestone. Only explicitly provided fields are changed.

    Args:
        project_id: Project the milestone belongs to (preserved for API parity;
            ownership scoping is enforced by user_id at the service layer).
        milestone_id: ID of the milestone to update.
        title: New title, or omit to leave unchanged.
        description: New one-line summary, or omit to leave unchanged.
        body: New plan/design (markdown), or omit to leave unchanged.
        status: New status — active or done.
        order_index: New display position (0-based). Use -1 to leave unchanged.
    """
    uid = current_user_id()
    fields: dict = {}
    if title:
        fields["title"] = title
    if description:
        fields["description"] = description
    if body:
        fields["body"] = body
    if status:
        fields["status"] = status
    if order_index >= 0:
        fields["order_index"] = order_index
    await refuse_guessed_ids(title, description, body)
    milestone = await milestones_svc.update_milestone(uid, milestone_id, **fields)
    if milestone is None:
        raise ValueError(f"milestone {milestone_id} not found")
    return milestone.to_dict()


async def delete_milestone(milestone_id: int) -> dict:
    """Move a milestone to the trash (recoverable). Its tasks go with it as one batch.
    Restore via restore(batch_id)."""
    uid = current_user_id()
    # Read the title BEFORE the delete: afterwards the row is trashed and the
    # confirmation could only echo the number back. A deletion the operator
    # cannot recognise is one they cannot tell was the wrong one.
    # Fail-open: the title is a COURTESY on top of the delete, so a lookup
    # that errors must not stop the delete happening. Same posture the
    # staleness marker takes — a decoration may never break its payload.
    try:
        doomed = await milestones_svc.get_milestone(uid, milestone_id)
        title = getattr(doomed, "title", "") if doomed else ""
    except Exception:
        title = ""
    batch = await trash_svc.delete(uid, "milestone", milestone_id)
    if batch is None:
        raise ValueError(f"milestone {milestone_id} not found")
    return {"deleted": milestone_id, "title": title, "deleted_batch_id": batch,
            "message": f'Milestone {milestone_id} ("{title}") and its tasks '
                       f"moved to trash. Restore with restore('{batch}')."}


def register(mcp) -> None:
    for fn in (
        list_milestones,
        get_milestone,
        create_milestone,
        update_milestone,
        delete_milestone,
    ):
        mcp.tool(name=fn.__name__)(fn)