"""One registry of the retrieval surfaces, and the two numbers each one has.

WHY THIS EXISTS

Every push arm has the same shape: a settings key, a default, and a limit. A
floor is chosen and adjusted by the model that uses it, with the operator able
to touch it — and a tuning surface cannot be consistent for the model if every
arm spells its own configuration differently. So the arms do not own their
numbers; they read them from here, and the tuning tool, the routes and the
Settings UI all enumerate THIS table rather than hard-coding special cases.

WHAT A FLOOR IS, AND WHAT IT IS NOT

It is not a relevance judgement. Relevance is decided by the reader, which is
the only participant that can read a trigger against a situation — and the
injected line says so out loud ("read it before deciding it does not apply").

A floor answers the cheaper question: *is this worth ranking at all*. `k` is
what binds, and `k` is a BUDGET — how much of this surface's attention a
candidate list may spend. An arm that fires before every Bash call cannot
afford what an arm that fires once a turn can.

WHY THE DEFAULTS BELOW ARE STARTING POINTS AND NOT ANSWERS

A cosine score is a distance in BAAI/bge-small-en-v1.5's vector space, measured
against one corpus. It cannot transfer to an install with different records,
and a shipped default cannot be defended from any one install's telemetry.
Grimoire ships a starting point and the means to correct it, so the values carry
the measurement that motivated them without claiming to be right for anybody
else.

HOW A FLOOR SHOULD ACTUALLY BE MOVED

By reading the records the floor refused — `retrieval_telemetry(
near_miss_samples=N)` returns them by id — and never by the percentile alone.
An arm can log dozens of consecutive declines with the refused score a hair
under the bar while every percentile says "lower it", and the refused record,
once read, turns out to be a false positive that a lower bar would deliver on
every matching act. The statistic and the correct action can point in opposite
directions, and only opening the record tells them apart.
"""
from __future__ import annotations

from grimoire.services.settings import bounded_float, get_setting
from grimoire.services.retrieval_pipeline import (  # noqa: F401 - Surface re-exported
    TUNED_ARMS, Surface,
)

# A budget nobody should be able to set past. Not a tuning value — a guard on
# the worst case, so a mistyped setting cannot turn a menu into a wall of text.
# Shared by every surface because it bounds the same thing everywhere: how many
# lines a single unsolicited injection may occupy.
MAX_BUDGET = 10


# THE TABLE IS READ OFF THE SPECS. Each ranked arm in
# `retrieval_pipeline` carries its own `Surface` — the floor and budget pair,
# its settings keys and defaults, and the prose a tuner reads — so an arm added
# there is tunable by construction, and nothing here can drift from it.
SURFACES: dict[str, Surface] = {
    arm.tuning.name: arm.tuning for arm in TUNED_ARMS if arm.tuning is not None
}

# Reserved slots are deliberately absent. `preference_slot`, `reuse_slot` and
# `lesson_slot` borrow their parent arm's floor and are hard-limited to one hit
# each, because their entire purpose is to guarantee a single line to a kind of
# record that keeps losing a general score contest — or, for
# `lesson_slot`, to a kind whose loss is total rather than merely a lost
# convenience, since a lesson has no act arm to fall back on and nobody browses
# lessons looking for one. A budget of "1" is the feature;
# exposing it as tunable would invite setting it to 0 and silently removing the
# guarantee.
#
# They are still logged under their own `source`, which is what keeps them
# judgeable without being tunable: `best_available_id` names the record each
# bar refused, so a slot that never places, or one that places weak hits, shows
# up as evidence rather than as an argument.


def surface_names() -> list[str]:
    """Every tunable surface, in a stable order for menus and listings."""
    return list(SURFACES)


def get_surface(name: str) -> Surface:
    """Look one up, refusing an unknown name loudly.

    A typo'd surface must not be writable. Settings keys are free-form strings
    in a generic table, so a tuning call naming `pretool_rule` would otherwise
    write a key nothing ever reads — a change that appears to succeed, reports a
    new value, and alters nothing.
    """
    try:
        return SURFACES[name]
    except KeyError:
        raise ValueError(
            f"unknown retrieval surface {name!r}. Tunable surfaces are: "
            + ", ".join(surface_names())
        ) from None


def dial_for_key(key: str) -> tuple[str, str] | None:
    """Which `(surface, dial)` a settings key belongs to, or None.

    The registry read backwards, and it exists for one caller: the generic
    `/api/settings` endpoint, which accepts any key at all. Without this, a
    floor written through that endpoint moves with no event recorded, and the
    tuning history says nothing happened — a trail with holes in it, which is
    worse than no trail because it reads as complete.

    Derived rather than listed so a seventh surface is covered the moment it is
    added here, which is the only way this stays true.

    A floor key several surfaces share resolves to the first of them;
    `set_dial` records the move on every surface in `sharing_floor`.
    """
    for surface in SURFACES.values():
        if key == surface.floor_key:
            return (surface.name, "floor")
        if key == surface.budget_key:
            return (surface.name, "budget")
    return None


def sharing_floor(name: str) -> list[str]:
    """Every surface that reads the same floor key as `name`, itself included.

    The rule arms share one bar, so moving one surface's floor moves its
    siblings, and each of them needs the event that says so.
    """
    key = get_surface(name).floor_key
    return [n for n, s in SURFACES.items() if s.floor_key == key]


async def floor_for(user_id: int, name: str) -> float:
    """This install's current floor for a surface, clamped to [0, 1]."""
    s = get_surface(name)
    raw = await get_setting(user_id, s.floor_key, str(s.floor_default))
    return bounded_float(raw, s.floor_default)


async def budget_for(user_id: int, name: str) -> int:
    """This install's current budget for a surface, clamped to [1, MAX_BUDGET].

    The lower clamp is 1, never 0: a surface turned off is turned off by its
    `enabled` switch, which says so. A budget of zero would be an arm that runs
    a search, logs a retrieval, and renders nothing — indistinguishable in the
    telemetry from a bar nothing cleared, which is the exact confusion this
    milestone exists to remove.
    """
    s = get_surface(name)
    raw = await get_setting(user_id, s.budget_key, "")
    if not raw and s.budget_falls_back_to:
        raw = await get_setting(user_id, s.budget_falls_back_to, "")
    try:
        value = int(float(raw)) if raw else s.budget_default
    except (TypeError, ValueError):
        value = s.budget_default
    return min(MAX_BUDGET, max(1, value))