"""Expose authenticated server-side statistics endpoints.

Probabilities and ranks are computed in Python, never by the model.
"""

from datetime import date, datetime, timezone

from fastapi import APIRouter, Depends, Query, Request

from app.deps import require_login
from app.models import ApiEnvelope, ok
from app.stats_math import build_stats, by_remedy

router = APIRouter(
    prefix="/api/stats",
    tags=["stats"],
    dependencies=[Depends(require_login)],
)


def _entry_dicts(request: Request) -> list[dict]:
    return [e.model_dump(mode="json") for e in request.app.state.entry_store._load()]


def _daily_dicts(
    request: Request,
    start: date | None,
    end: date | None,
) -> list[dict]:
    rows = request.app.state.daily_store._load()
    out = []
    for row in rows:
        if start and row.date < start:
            continue
        if end and row.date > end:
            continue
        out.append(row.model_dump(mode="json"))
    return out


def _filter_entries(
    entries: list[dict],
    start: date | None,
    end: date | None,
) -> list[dict]:
    if start is None and end is None:
        return entries
    filtered = []
    for entry in entries:
        ts = entry.get("ts")
        if isinstance(ts, str):
            day = date.fromisoformat(ts[:10])
        else:
            continue
        if start and day < start:
            continue
        if end and day > end:
            continue
        filtered.append(entry)
    return filtered


@router.get("", response_model=ApiEnvelope)
def get_stats(
    request: Request,
    start: date | None = None,
    end: date | None = None,
    min_n: int | None = Query(default=None, ge=1),
) -> dict[str, object]:
    """Return aggregate statistics for entries and daily rows."""

    settings = request.app.state.settings
    effective_min_n = settings.min_stats_n if min_n is None else min_n
    entries = _filter_entries(_entry_dicts(request), start, end)
    daily = _daily_dicts(request, start, end)
    payload = build_stats(
        entries,
        daily,
        min_n=effective_min_n,
        shrink_k=settings.stats_shrink_k,
        generated_at=datetime.now(timezone.utc).isoformat(),
    )
    return ok(payload)


@router.get("/remedies", response_model=ApiEnvelope)
def get_remedy_leaderboard(
    request: Request,
    start: date | None = None,
    end: date | None = None,
    min_n: int | None = Query(default=None, ge=1),
) -> dict[str, object]:
    """Return remedies sorted by shrinkage rank."""

    settings = request.app.state.settings
    effective_min_n = settings.min_stats_n if min_n is None else min_n
    entries = _filter_entries(_entry_dicts(request), start, end)
    rows = by_remedy(
        entries,
        min_n=effective_min_n,
        shrink_k=settings.stats_shrink_k,
    )
    return ok({"items": rows, "min_n": effective_min_n})