"""Every getter that opens ONE note-backed record must record the pull.

WHY THIS EXISTS

`note_usage_events` answers "did anyone ever actually open this?" — the
surfaced:pulled ratio is what makes dead weight visible and prunable. A getter
that opens a record without recording it leaves that kind permanently at zero
pulls, so it looks like dead weight beside kinds that merely had a counter.

That has now happened twice:

  #2245  `get_task` recorded nothing while auto-inject surfaced mostly tasks.
         Fixed by adding the call to notes, tasks and snippets.
  #2476  `get_process` recorded nothing — and the auto-inject menu header names
         `get_process` as the way to open that kind. Processes were embedded
         when #2245 was fixed; the fix enumerated the kinds someone thought of
         rather than the kinds that exist.

A missing call is the shape no behavioural test catches: it changes no return
value (#2278, shape 4). Source inspection is the only thing that sees it.

WHAT MAKES THIS DERIVED RATHER THAN A LIST

The getters are not enumerated here. They are discovered from the tool modules
by AST, and the ones that must record are identified by the loader they call —
so a `get_<newkind>` added tomorrow is covered the moment it loads a note the
way every other getter does.

The loader names ARE a list, and that is the residual weakness. The second test
pins them against a RENAME — the failure mode that would silently empty the
candidate set and let this pass while checking nothing.

It does not discover NEW loaders, and an earlier draft that tried to failed for
the wrong reason: `create_note` and `update_note` also return a `Note`, so an
annotation scan finds writers, not readers. Distinguishing them needs more than
a type, so the honest position is a pinned list plus a non-empty assertion,
and this paragraph saying so.
"""
from __future__ import annotations

import ast
import inspect
import pathlib
import pkgutil

# Loaders that return ONE note-backed record in full. A getter calling any of
# these is opening a record, which is the act `pulled` describes.
#
# `list_notes` is deliberately absent: `get_milestone` calls it to list a
# milestone's steps, and that is a LIST — the milestone itself is not a note,
# and its steps are surfaced rather than opened.
SINGLE_NOTE_LOADERS = (
    "get_note_for_user",
    "resolve_process",
    "get_snippet",
)

TOOLS_DIR = pathlib.Path(__file__).resolve().parents[1] / "src" / "scribe" / "mcp" / "tools"


def _getters():
    """(module name, function name, source) for every `get_*` MCP tool."""
    for mod in pkgutil.iter_modules([str(TOOLS_DIR)]):
        path = TOOLS_DIR / f"{mod.name}.py"
        source = path.read_text()
        for node in ast.parse(source).body:
            if isinstance(node, ast.AsyncFunctionDef) and node.name.startswith("get_"):
                yield mod.name, node.name, ast.get_source_segment(source, node) or ""


def test_every_single_record_getter_records_a_pull():
    missing = []
    checked = []
    for module, name, body in _getters():
        if not any(loader in body for loader in SINGLE_NOTE_LOADERS):
            continue
        checked.append(f"{module}.{name}")
        if "record_pulled" not in body:
            missing.append(f"{module}.{name}")

    # If this ever drops to zero the test has stopped testing anything — a
    # renamed loader would silently empty the candidate set and pass.
    assert checked, "found no note-backed getters; the loader names must have moved"
    assert not missing, (
        f"these getters open a record without recording the pull: {missing}. "
        f"Add record_pulled(user_id=…, note_id=…, source='mcp_<tool>') before "
        f"returning — see mcp/tools/notes.py:get_note."
    )


def test_every_named_loader_still_exists():
    """Pins the hand-written list against a rename.

    A renamed loader is the failure that matters: the candidate set above would
    quietly empty and the first test would pass while checking nothing. The
    `assert checked` there catches it too; this says WHICH name moved, which is
    the difference between a five-minute fix and a puzzle.
    """
    from scribe.services import notes as notes_svc
    from scribe.services import snippets as snippets_svc

    available = {
        name
        for svc in (notes_svc, snippets_svc)
        for name, obj in vars(svc).items()
        if inspect.iscoroutinefunction(obj)
    }
    gone = [name for name in SINGLE_NOTE_LOADERS if name not in available]
    assert not gone, (
        f"SINGLE_NOTE_LOADERS names {gone} that no longer exist — they were "
        f"renamed or moved. Update the list, or the pull check silently stops "
        f"covering whatever used them."
    )