src/stats.py

"""Pass / fail / ungraded counts and themed dashboard HTML for the Stats page."""

from __future__ import annotations

import difflib
import html
import re
from collections import Counter
from dataclasses import dataclass

import pandas as pd
from grades import is_graded_verdict, normalize_grades

DEFAULT_FAIL_REASONS: tuple[str, ...] = (
    "Completeness",
    "Relevance",
    "Clarity",
    "Correctness",
)
OTHER_REASON = "Other"
_TYPO_CUTOFF = 0.8
_MIN_EXTRA_FAIL_COUNT = 3  # more than twice
_ANSWERS_SUFFIXES = ("_answers.parquet", "_answers.csv")
SWIPE_TEMPLATE_COLUMNS: tuple[str, ...] = (
    "term",
    "field_of_law",
    "concept",
    "section",
    "section_index",
    "question_id",
    "group",
    "part",
    "question",
    "question_index",
    "answer",
    "source_fields",
    "source_prompts",
)


def missing_template_columns(columns: object) -> tuple[str, ...]:
    """Return swipe-deck columns absent from a template frame."""
    present = {str(name) for name in columns}
    return tuple(name for name in SWIPE_TEMPLATE_COLUMNS if name not in present)


def is_test_user(record: object) -> bool:
    """True when the users.json record is flagged ``test_user``."""
    return _true_flag(record, "test_user")


def is_admin(record: object) -> bool:
    """True when the users.json record is flagged ``admin``."""
    return _true_flag(record, "admin")


def is_trashed(record: object) -> bool:
    """True when the users.json record is flagged ``trashed``."""
    return _true_flag(record, "trashed")


def _true_flag(record: object, key: str) -> bool:
    if not isinstance(record, dict):
        return False
    return bool(record.get(key))


def production_usernames(users: dict[str, object]) -> set[str]:
    """Registered graders: not test users and not trashed."""
    return {
        name
        for name, record in users.items()
        if not is_test_user(record) and not is_trashed(record)
    }


_SPARSE_TRUE_FLAGS = ("test_user", "admin", "trashed")


def compact_user_record(record: object) -> dict[str, object]:
    """Copy a users.json row, keeping only ``true`` boolean flags."""
    if not isinstance(record, dict):
        return {"password": record}
    row = dict(record)
    for key in _SPARSE_TRUE_FLAGS:
        if key not in row:
            continue
        if row[key]:
            row[key] = True
        else:
            del row[key]
    return row


def compact_users(users: dict[str, object]) -> dict[str, dict[str, object]]:
    """Compact every account record in a users.json mapping."""
    return {name: compact_user_record(record) for name, record in users.items()}


def stamp_test_user_flags(
    users: dict[str, object],
    *,
    production_names: frozenset[str],
) -> dict[str, dict[str, object]]:
    """Copy accounts; set ``test_user`` only for names outside the allowlist."""
    stamped: dict[str, dict[str, object]] = {}
    for name, record in users.items():
        row = compact_user_record(record)
        if name not in production_names:
            row["test_user"] = True
        else:
            row.pop("test_user", None)
        stamped[name] = compact_user_record(row)
    return stamped


def apply_account_edit(
    users: dict[str, object],
    old_name: str,
    *,
    new_username: str = "",
    new_password_hash: str | None = None,
) -> tuple[dict[str, dict[str, object]], str | None, str]:
    """Rename and/or rehash one account. Empty fields are left unchanged."""
    if old_name not in users:
        return compact_users(users), "Username not found", old_name
    wanted = new_username.strip()
    resulting = wanted or old_name
    if wanted and wanted != old_name and wanted in users:
        return compact_users(users), "Username already exists", old_name
    updated = compact_users(users)
    row = dict(updated.pop(old_name))
    if new_password_hash:
        row["password"] = new_password_hash
    if not wanted and not new_password_hash:
        return compact_users(users), "Nothing to save", old_name
    updated[resulting] = compact_user_record(row)
    return updated, None, resulting


def new_user_record(
    password_hash: str, *, test_user: bool = False
) -> dict[str, object]:
    """Build a sparse users.json row. ``test_user`` is omitted when false."""
    row: dict[str, object] = {"password": password_hash}
    if test_user:
        row["test_user"] = True
    return compact_user_record(row)


def account_edit_ready(new_username: str, new_password: str) -> bool:
    """True when Save may run: at least one edit field has text."""
    return bool(str(new_username or "").strip() or str(new_password or ""))


def set_account_trashed(
    users: dict[str, object],
    name: str,
    *,
    trashed: bool = True,
) -> tuple[dict[str, dict[str, object]], str | None]:
    """Toggle the sparse ``trashed`` flag on one account."""
    if name not in users:
        return compact_users(users), "Username not found"
    updated = compact_users(users)
    row = dict(updated[name])
    if trashed:
        row["trashed"] = True
    else:
        row.pop("trashed", None)
    updated[name] = compact_user_record(row)
    return updated, None


def delete_account(
    users: dict[str, object], name: str
) -> tuple[dict[str, dict[str, object]], str | None]:
    """Remove one account from users.json."""
    if name not in users:
        return compact_users(users), "Username not found"
    updated = compact_users(users)
    updated.pop(name, None)
    return updated, None


def partition_console_users(
    users: dict[str, object],
    *,
    omit: str | None = None,
) -> tuple[list[str], list[str]]:
    """Split registered names into graders vs test users (trashed stay listed).

    ``omit`` hides one account (the signed-in admin) without hiding other admins.
    """
    graders: list[str] = []
    testers: list[str] = []
    skipped = omit or ""
    for name in sorted(users):
        if name == skipped:
            continue
        if is_test_user(users[name]):
            testers.append(name)
        else:
            graders.append(name)
    return graders, testers


def can_persist_grades(view_as: str | None) -> bool:
    """False while an admin is in read-only View as."""
    return not bool(view_as)


def display_username(session_username: str, view_as: str | None) -> str:
    """Name whose deck/stats to show. Login identity stays ``session_username``."""
    return str(view_as) if view_as else session_username


def ensure_admin_account(
    users: dict[str, object],
    *,
    password_hash: str,
) -> dict[str, dict[str, object]]:
    """Insert or refresh the ``admin`` account (admin + test_user, not trashed)."""
    updated = compact_users(users)
    row = dict(updated.get("admin") or {})
    row["password"] = password_hash
    row["admin"] = True
    row["test_user"] = True
    row.pop("trashed", None)
    updated["admin"] = compact_user_record(row)
    return updated


@dataclass(frozen=True)
class GradeCounts:
    """One grader's (or a rolled-up group's) Pass / fail / ungraded split."""

    passed: int
    failed: int
    ungraded: int
    fail_reasons: dict[str, int]

    @property
    def graded(self) -> int:
        return self.passed + self.failed

    @property
    def total(self) -> int:
        return self.passed + self.failed + self.ungraded

    def add(self, other: GradeCounts) -> GradeCounts:
        reasons = dict(self.fail_reasons)
        for name, count in other.fail_reasons.items():
            reasons[name] = reasons.get(name, 0) + count
        return GradeCounts(
            passed=self.passed + other.passed,
            failed=self.failed + other.failed,
            ungraded=self.ungraded + other.ungraded,
            fail_reasons=reasons,
        )


def empty_counts(fail_reasons: tuple[str, ...] = DEFAULT_FAIL_REASONS) -> GradeCounts:
    """Zeroed counts with a slot for each named fail reason plus Other."""
    return GradeCounts(
        passed=0,
        failed=0,
        ungraded=0,
        fail_reasons=_empty_reasons(fail_reasons),
    )


def sum_counts(*items: GradeCounts | None) -> GradeCounts:
    """Add counts; skip None. Empty input yields zeros with default reasons."""
    acc: GradeCounts | None = None
    for item in items:
        if item is None:
            continue
        acc = item if acc is None else acc.add(item)
    return acc if acc is not None else empty_counts()


def percent(part: int, whole: int) -> float:
    """Return ``part`` as a percentage of ``whole``, or 0 when whole is 0."""
    if whole <= 0:
        return 0.0
    return 100.0 * part / whole


def segment_widths(parts: tuple[int, ...]) -> tuple[float, ...]:
    """Percent widths that sum to 100 when any part is positive."""
    total = sum(parts)
    if total <= 0:
        return tuple(0.0 for _ in parts)
    rounded = [round(100.0 * n / total, 4) for n in parts]
    drift = round(100.0 - sum(rounded), 4)
    for index in range(len(rounded) - 1, -1, -1):
        if parts[index] > 0:
            rounded[index] = round(rounded[index] + drift, 4)
            break
    return tuple(rounded)


def username_from_answers_filename(name: str) -> str | None:
    """Parse ``alice`` from ``alice_answers.parquet`` or ``…/alice_answers.csv``."""
    base = name.rsplit("/", 1)[-1]
    for suffix in _ANSWERS_SUFFIXES:
        if base.endswith(suffix):
            user = base[: -len(suffix)]
            return user or None
    return None


def grades_to_verdicts(
    df: pd.DataFrame | None,
) -> dict[tuple[object, object, object], object]:
    """Map sparse or template-shaped grade rows to ``(term, fol, qid) → verdict``."""
    graded = normalize_grades(df)
    out: dict[tuple[object, object, object], object] = {}
    if graded.empty:
        return out
    for term, field, question_id, verdict in zip(
        graded["term"],
        graded["field_of_law"],
        graded["question_id"],
        graded["verdict"],
        strict=True,
    ):
        out[(term, field, question_id)] = verdict
    return out


def overlay_verdicts(
    stored: dict[tuple[object, object, object], object],
    session: dict[object, object],
) -> dict[tuple[object, object, object], object]:
    """Copy ``stored``, then apply in-session Pass/fail (and ignore empty skip)."""
    merged = dict(stored)
    for key, verdict in session.items():
        if not is_graded_verdict(verdict):
            continue
        if not isinstance(key, tuple) or len(key) != 3:
            continue
        merged[(key[0], key[1], key[2])] = verdict
    return merged


def normalize_fail_label(raw: object) -> str:
    """Strip, collapse whitespace, and casefold a fail verdict for clustering."""
    text = re.sub(r"\s+", " ", str(raw).strip())
    return text.casefold()


def match_canonical_fail(
    label: str,
    fail_reasons: tuple[str, ...] = DEFAULT_FAIL_REASONS,
    *,
    cutoff: float = _TYPO_CUTOFF,
) -> str | None:
    """Return a button fail reason when ``label`` matches exactly or as a typo."""
    folded = normalize_fail_label(label)
    if not folded:
        return None
    by_fold = {normalize_fail_label(name): name for name in fail_reasons}
    if folded in by_fold:
        return by_fold[folded]
    matches = difflib.get_close_matches(
        folded, list(by_fold.keys()), n=1, cutoff=cutoff
    )
    if not matches:
        return None
    return by_fold[matches[0]]


def cluster_fail_labels(
    labels: list[str],
    fail_reasons: tuple[str, ...] = DEFAULT_FAIL_REASONS,
    *,
    cutoff: float = _TYPO_CUTOFF,
) -> dict[str, int]:
    """Map display labels to counts, folding case and typos onto button reasons."""
    counts: dict[str, int] = {name: 0 for name in fail_reasons}
    free_raw: list[str] = []
    for raw in labels:
        text = re.sub(r"\s+", " ", str(raw).strip())
        if not text:
            continue
        canonical = match_canonical_fail(text, fail_reasons, cutoff=cutoff)
        if canonical is not None:
            counts[canonical] = counts.get(canonical, 0) + 1
            continue
        free_raw.append(text)

    # Cluster remaining free-text: casefold first, then typo-fold onto cluster keys.
    fold_to_display: dict[str, str] = {}
    fold_counts: Counter[str] = Counter()
    display_votes: dict[str, Counter[str]] = {}
    for text in free_raw:
        folded = normalize_fail_label(text)
        if folded in fold_to_display:
            key = folded
        else:
            matches = difflib.get_close_matches(
                folded, list(fold_to_display.keys()), n=1, cutoff=cutoff
            )
            key = matches[0] if matches else folded
            if key not in fold_to_display:
                fold_to_display[key] = text
        fold_counts[key] += 1
        display_votes.setdefault(key, Counter())[text] += 1

    for key, n in fold_counts.items():
        display = display_votes[key].most_common(1)[0][0]
        counts[display] = counts.get(display, 0) + n
    return counts


def fail_type_rows(
    catalog_counts: dict[str, int],
    fail_reasons: tuple[str, ...] = DEFAULT_FAIL_REASONS,
    *,
    min_extra_count: int = _MIN_EXTRA_FAIL_COUNT,
) -> tuple[str, ...]:
    """Button reasons, then free-text clusters with count > 2, then Other if needed."""
    rows = list(fail_reasons)
    extras = [
        (name, n)
        for name, n in catalog_counts.items()
        if name not in fail_reasons and name != OTHER_REASON and n >= min_extra_count
    ]
    extras.sort(key=lambda item: (-item[1], item[0].casefold()))
    rows.extend(name for name, _ in extras)
    leftover = sum(
        n
        for name, n in catalog_counts.items()
        if name not in fail_reasons and name != OTHER_REASON and n < min_extra_count
    )
    leftover += catalog_counts.get(OTHER_REASON, 0)
    if leftover > 0:
        rows.append(OTHER_REASON)
    return tuple(rows)


def project_fail_reasons(
    counts: GradeCounts,
    row_names: tuple[str, ...],
    fail_reasons: tuple[str, ...] = DEFAULT_FAIL_REASONS,
) -> dict[str, int]:
    """Project a grader's fail_reasons onto the shared Fail by type row catalog."""
    projected = {name: 0 for name in row_names}
    named = set(row_names)
    for name, n in counts.fail_reasons.items():
        if name in named and name != OTHER_REASON:
            projected[name] = projected.get(name, 0) + n
        elif OTHER_REASON in named:
            projected[OTHER_REASON] = projected.get(OTHER_REASON, 0) + n
    # Ensure button reasons exist even when absent from the grader's dict.
    for name in fail_reasons:
        if name in projected:
            projected.setdefault(name, 0)
    return projected


def toggle_open_grader(open_names: list[str], name: str) -> list[str]:
    """Append ``name`` if absent; remove it if present. Preserve click order."""
    if name in open_names:
        return [item for item in open_names if item != name]
    return [*open_names, name]


def prune_open_graders(
    open_names: list[str], available: set[str] | frozenset[str]
) -> list[str]:
    """Drop open graders that are no longer in the Other graders list."""
    return [name for name in open_names if name in available]


def counts_from_verdicts(
    verdicts: dict[object, object],
    total_cards: int,
    *,
    pass_label: str = "Pass",
    fail_reasons: tuple[str, ...] = DEFAULT_FAIL_REASONS,
) -> GradeCounts:
    """Split verdicts into Pass, fail (by clustered reason), and ungraded cards."""
    passed = 0
    failed = 0
    fail_labels: list[str] = []
    for verdict in verdicts.values():
        if not is_graded_verdict(verdict):
            continue
        label = str(verdict).strip()
        if label == pass_label:
            passed += 1
            continue
        failed += 1
        fail_labels.append(label)
    reasons = cluster_fail_labels(fail_labels, fail_reasons)
    # Preserve Other slot for callers that expect it when nothing free-texted.
    reasons.setdefault(OTHER_REASON, 0)
    ungraded = max(0, int(total_cards) - passed - failed)
    return GradeCounts(
        passed=passed,
        failed=failed,
        ungraded=ungraded,
        fail_reasons=reasons,
    )


def dashboard_html(
    *,
    everyone: GradeCounts,
    you: GradeCounts,
    you_name: str,
    others: list[tuple[str, GradeCounts]],
    jurisdictions: list[tuple[str, str, GradeCounts]],
    fail_reasons: tuple[str, ...] = DEFAULT_FAIL_REASONS,
    you_is_test_user: bool = False,
    open_others: list[tuple[str, GradeCounts]] | None = None,
) -> str:
    """Return the Stats page body (hero, aggregated, you, other graders)."""
    open_others = open_others or []
    catalog = dict(everyone.fail_reasons)
    if you_is_test_user:
        for name, n in you.fail_reasons.items():
            catalog[name] = catalog.get(name, 0) + n
    row_names = fail_type_rows(catalog, fail_reasons)

    styles: list[str] = []
    everyone_bar = _stacked_bar_html("stats-bar-everyone", everyone, styles)
    reason_block = _fail_reasons_html(
        "stats-reason-everyone",
        everyone,
        row_names,
        styles,
    )
    juri_block = _jurisdiction_block_html(jurisdictions, styles)
    open_names = {name for name, _ in open_others}
    others_block = _others_grid_html(others, styles, open_names=open_names)
    you_role = "Test user (excluded from aggregation)" if you_is_test_user else "Grader"
    you_panel = _grader_panel_html(
        title=you_name,
        role=you_role,
        counts=you,
        team_graded=everyone.graded,
        bar_id="stats-bar-you",
        reason_prefix="stats-reason-you",
        row_names=row_names,
        styles=styles,
        caption_self=True,
    )
    open_panels = []
    for index, (name, counts) in enumerate(open_others):
        open_panels.append(
            _grader_panel_html(
                title=name,
                role="Grader",
                counts=counts,
                team_graded=everyone.graded,
                bar_id=f"stats-bar-open-{_css_id(name)}-{index}",
                reason_prefix=f"stats-reason-open-{_css_id(name)}-{index}",
                row_names=row_names,
                styles=styles,
                caption_self=False,
            )
        )
    style_tag = f"<style>{''.join(styles)}</style>" if styles else ""
    return (
        f"{style_tag}"
        '<div class="stats-page">'
        '<div class="stats-hero">'
        '<h1 class="stats-hero-title">Grading stats</h1>'
        '<p class="stats-hero-kicker">'
        "Pass, fail, and ungraded cards across every jurisdiction with a template."
        "</p>"
        "</div>"
        '<section class="stats-panel">'
        '<div class="stats-panel-head">'
        "<h2>Aggregated results</h2>"
        '<p class="stats-muted">All graders · all jurisdictions</p>'
        "</div>"
        f"{_kpi_row_html(everyone)}"
        f"{everyone_bar}"
        f"{_legend_html()}"
        f"{reason_block}"
        f"{juri_block}"
        "</section>"
        f"{you_panel}"
        '<section class="stats-panel">'
        '<div class="stats-panel-head">'
        "<h2>Other graders</h2>"
        '<p class="stats-muted">Click on graders to see their stats</p>'
        "</div>"
        f"{others_block}"
        "</section>"
        f"{''.join(open_panels)}"
        "</div>"
    )


def _empty_reasons(fail_reasons: tuple[str, ...]) -> dict[str, int]:
    return {name: 0 for name in (*fail_reasons, OTHER_REASON)}


def _fmt(value: int) -> str:
    return f"{value:,}"


def _fmt_pct(value: float) -> str:
    if value == 0:
        return "0%"
    if value < 0.1:
        return f"{value:.2f}%"
    if value < 10:
        return f"{value:.1f}%"
    return f"{value:.0f}%"


def _css_id(label: str) -> str:
    slug = re.sub(r"[^a-zA-Z0-9_-]+", "-", label).strip("-")
    return slug or "x"


def _kpi_row_html(counts: GradeCounts) -> str:
    total = counts.total
    tiles = (
        ("pass", "Pass", counts.passed),
        ("fail", "Fail", counts.failed),
        ("ungraded", "Ungraded", counts.ungraded),
    )
    parts = []
    for kind, label, value in tiles:
        parts.append(
            f'<div class="stats-kpi stats-kpi-{kind}">'
            f'<div class="stats-kpi-label">{label}</div>'
            f'<div class="stats-kpi-value">{_fmt(value)}</div>'
            f'<div class="stats-kpi-pct">{_fmt_pct(percent(value, total))} of deck</div>'
            "</div>"
        )
    return f'<div class="stats-kpi-row">{"".join(parts)}</div>'


def _stacked_bar_html(bar_id: str, counts: GradeCounts, styles: list[str]) -> str:
    widths = segment_widths((counts.passed, counts.failed, counts.ungraded))
    styles.append(
        f"#{bar_id} .seg-pass{{width:{widths[0]:.4f}%!important}}"
        f"#{bar_id} .seg-fail{{width:{widths[1]:.4f}%!important}}"
        f"#{bar_id} .seg-ungraded{{width:{widths[2]:.4f}%!important}}"
    )
    label = (
        f"{_fmt(counts.passed)} pass, {_fmt(counts.failed)} fail, "
        f"{_fmt(counts.ungraded)} ungraded"
    )
    return (
        f'<div class="stats-bar" id="{bar_id}" role="img" '
        f'aria-label="{html.escape(label)}">'
        '<span class="seg seg-pass"></span>'
        '<span class="seg seg-fail"></span>'
        '<span class="seg seg-ungraded"></span>'
        "</div>"
    )


def _legend_html() -> str:
    chips = (
        ("pass", "Pass"),
        ("fail", "Fail"),
        ("ungraded", "Ungraded"),
    )
    parts = [
        f'<span class="stats-legend-chip stats-legend-{kind}">'
        f'<span class="stats-legend-swatch"></span>{label}</span>'
        for kind, label in chips
    ]
    return f'<div class="stats-legend">{"".join(parts)}</div>'


def _grader_panel_html(
    *,
    title: str,
    role: str,
    counts: GradeCounts,
    team_graded: int,
    bar_id: str,
    reason_prefix: str,
    row_names: tuple[str, ...],
    styles: list[str],
    caption_self: bool,
) -> str:
    """You-style panel: KPIs, bar, legend, Fail by type, share caption."""
    bar = _stacked_bar_html(bar_id, counts, styles)
    reasons = _fail_reasons_html(reason_prefix, counts, row_names, styles)
    share = percent(counts.graded, team_graded)
    who = "You have" if caption_self else f"{html.escape(title)} has"
    possessive = "your" if caption_self else "their"
    return (
        '<section class="stats-panel stats-panel-you">'
        '<div class="stats-panel-head">'
        f"<h2>{html.escape(title)}</h2>"
        f'<p class="stats-muted">{html.escape(role)}</p>'
        "</div>"
        f"{_kpi_row_html(counts)}"
        f"{bar}"
        f"{_legend_html()}"
        f"{reasons}"
        '<p class="stats-caption">'
        f"{who} graded {_fmt(counts.graded)} of {_fmt(counts.total)} cards "
        f"({_fmt_pct(percent(counts.graded, counts.total))} of {possessive} deck). "
        f"That is {_fmt_pct(share)} of every card graded by the team."
        "</p>"
        "</section>"
    )


def _fail_reasons_html(
    prefix: str,
    counts: GradeCounts,
    row_names: tuple[str, ...],
    styles: list[str],
) -> str:
    if counts.failed <= 0:
        return '<p class="stats-caption">No fails recorded yet.</p>'
    projected = project_fail_reasons(counts, row_names)
    peak = max((projected.get(name, 0) for name in row_names), default=0) or 1
    rows = []
    for name in row_names:
        n = projected.get(name, 0)
        row_id = f"{prefix}-{_css_id(name)}"
        width = round(100.0 * n / peak, 4)
        styles.append(f"#{row_id} .stats-reason-fill{{width:{width:.4f}%!important}}")
        rows.append(
            f'<div class="stats-reason-row" id="{row_id}">'
            f'<div class="stats-reason-name">{html.escape(name)}</div>'
            '<div class="stats-reason-track"><div class="stats-reason-fill"></div></div>'
            f'<div class="stats-reason-n">{_fmt(n)}</div>'
            "</div>"
        )
    return (
        '<div class="stats-reasons">'
        '<div class="stats-subhead">Fail by type</div>'
        f"{''.join(rows)}"
        "</div>"
    )


def _jurisdiction_block_html(
    jurisdictions: list[tuple[str, str, GradeCounts]],
    styles: list[str],
) -> str:
    if len(jurisdictions) < 2:
        return ""
    rows = []
    for code, label, counts in jurisdictions:
        bar_id = f"stats-bar-j-{_css_id(code)}"
        bar = _stacked_bar_html(bar_id, counts, styles)
        rows.append(
            '<div class="stats-juri-row">'
            f'<div class="stats-juri-name">{html.escape(label)}</div>'
            f"{bar}"
            f'<div class="stats-juri-nums">{_fmt(counts.passed)} · '
            f"{_fmt(counts.failed)} · {_fmt(counts.ungraded)}</div>"
            "</div>"
        )
    return (
        '<div class="stats-juris">'
        '<div class="stats-subhead">By jurisdiction</div>'
        f"{''.join(rows)}"
        "</div>"
    )


def _others_grid_html(
    others: list[tuple[str, GradeCounts]],
    styles: list[str],
    *,
    open_names: set[str] | frozenset[str] | None = None,
) -> str:
    if not others:
        return '<p class="stats-caption">No other graders yet.</p>'
    open_names = open_names or set()
    cards = []
    for name, counts in others:
        bar_id = f"stats-bar-user-{_css_id(name)}"
        bar = _stacked_bar_html(bar_id, counts, styles)
        open_cls = " stats-user-card-open" if name in open_names else ""
        cards.append(
            f'<div class="stats-user-card{open_cls}" role="button" tabindex="0" '
            f'data-grader="{html.escape(name, quote=True)}">'
            f'<div class="stats-user-name">{html.escape(name)}</div>'
            f"{bar}"
            f'<div class="stats-user-nums">'
            f'<span class="stats-num-pass">{_fmt(counts.passed)} pass</span>'
            f'<span class="stats-num-fail">{_fmt(counts.failed)} fail</span>'
            f'<span class="stats-num-ungraded">{_fmt(counts.ungraded)} left</span>'
            "</div>"
            "</div>"
        )
    return f'<div class="stats-users">{"".join(cards)}</div>'