vyndr/src/services/retentionService.js

'use strict';

/**
 * MODEL SNAPSHOT RETENTION (Session 64, Phase 2 — priority zero).
 *
 * As of 2026-07-20 the only store of model history was `ledger_entries`: 640
 * rows, 6 game days, and NO MODEL INPUTS. Every other warehouse table in the
 * schema was empty. That meant we could score the grades we emitted but could
 * not replay a different model against the same conditions — the only question
 * a backtest exists to answer, and the gate the metrics-engine north star
 * requires ("does this metric predict better than without it?").
 *
 * This writes `model_snapshots`: one APPEND-ONLY row per graded prop per
 * snapshot cycle, carrying the market values, the model output, the refusal
 * (if any), and the FEATURE VECTOR that produced it.
 *
 * CONTRACT: best-effort, exactly like the ledger write. A retention failure
 * must NEVER break a snapshot. Every path returns a summary; none throw.
 *
 * Two deliberate choices:
 *  - REFUSALS ARE STORED. The ledger drops them, so a gate that refuses props
 *    which would have won is invisible. That is lost edge we cannot measure.
 *  - EVERY ROW IS STAMPED with model_version + code_sha. A backtest that mixes
 *    model eras is worthless, and `ledger_entries` is already permanently
 *    contaminated across the 2026-07-19 fix boundary with no way to separate.
 */

const crypto = require('crypto');
const { normalizeName, nameKey } = require('../utils/playerName');
const { semanticPlayerKey } = require('./model/participantIdentity');

/** ET calendar date of an ISO timestamp (shares gameBinder's rule). */
function etDateOf(iso) {
  if (!iso) return null;
  const t = new Date(iso);
  if (Number.isNaN(t.getTime())) return null;
  return new Intl.DateTimeFormat('en-CA', {
    timeZone: 'America/New_York', year: 'numeric', month: '2-digit', day: '2-digit',
  }).format(t);
}

/**
 * Bump when the grading model changes in a way that makes rows non-comparable.
 * This is the marker `ledger_entries` never had.
 */
/**
 * CHAMPION VERSION — the eligibility marker for every forward re-audit.
 *
 * Bumped when the forecaster itself changes, so a settled row is
 * self-identifying: rows tagged `engine1@2026-08-07-fullwindow` were produced by
 * the REPAIRED champion (full season log, recency weight 0.20); anything earlier
 * came from the retired ten-game forecaster.
 *
 * This is what makes the re-audit rule mechanical rather than a promise.
 * Calibration may only be re-fit, and factor verdicts may only be re-audited, on
 * rows carrying the current marker — never on reconstructions of a retired
 * forecast, and never on a mixture of the two, which is the trap that would
 * otherwise be invisible once both generations sit in the same table.
 */
// FIX A3 — ONE SOURCE (src/config/modelVersion.js). Re-exported so existing
// importers keep working, but never re-declared: the twin default in
// ledgerService is exactly how these two drifted apart.
const { MODEL_VERSION, REPAIRED_CHAMPION_VERSION } = require('../config/modelVersion');

function codeSha() {
  return process.env.SOURCE_COMMIT || process.env.GIT_SHA || process.env.COOLIFY_GIT_COMMIT_SHA || null;
}

/** Strict numeric parse — `Number(null) === 0` is this codebase's classic
 *  fabrication bug, so absent must stay absent. */
function numOrNull(v) {
  if (v == null || v === '') return null;
  const n = Number(v);
  return Number.isFinite(n) ? n : null;
}

function intOrNull(v) {
  const n = numOrNull(typeof v === 'string' ? v.replace('+', '') : v);
  return n == null ? null : Math.round(n);
}

function boolOrNull(v) {
  return typeof v === 'boolean' ? v : null;
}

/**
 * Build retention rows from ONE prop's graded sides (both over and under,
 * graded or refused). `base` is the prop the grader was called with.
 */
function rowsFromSides(base, sides, ctx = {}) {
  const rows = [];
  // `published` is declared on every row and defaults FALSE. A capture is not a
  // publication until the winner signal says so; defaulting true would assert
  // that 65% of these rows were shown to a user.
  
  const list = Array.isArray(sides) ? sides : [];
  for (const s of list) {
    if (!s) continue;
    const player = s.player || base.player;
    if (!player) continue;
    // SEMANTIC PLAYER IDENTITY. When MLB has proven who this participant is,
    // the identity comes from the league's own name for them, so every book's
    // spelling converges. When it has not, the raw spelling is used exactly as
    // before — we never guess a human into existence. The raw provider string
    // is untouched here and survives verbatim in closing_captures.
    const identity = semanticPlayerKey({
      player,
      mlb_person_id: s.mlb_person_id ?? base.mlb_person_id ?? null,
      canonical_player_name: s.canonical_player_name ?? base.canonical_player_name ?? null,
    });
    const stat = s.stat_type || base.stat_type;
    const line = numOrNull(s.line != null ? s.line : base.line);
    const side = String(s.direction || '').toLowerCase();
    if (!stat || line == null || (side !== 'over' && side !== 'under')) continue;

    const refused = !!(s.insufficient_data || !s.grade);

    rows.push({
      snapshot_id: ctx.snapshotId,
      captured_at: ctx.capturedAt,
      cycle_hour_utc: ctx.cycleHourUtc ?? null,
      model_version: MODEL_VERSION,
      code_sha: codeSha(),

      sport: ctx.sport,
      game_id: ctx.gameIdFor ? ctx.gameIdFor(base, s) : (base.game_id || `${ctx.sport}:${ctx.gameDate}`),
      // Session 64 (Order 1.5) — the GAME's date, from the bound game_time,
      // never the snapshot clock. ctx.gameDate is only a last resort for props
      // the binder could not tie to a real game.
      game_date: etDateOf(base && base.game_time) || ctx.gameDate,
      player_key: identity.key,
      // RAW SOURCE NAME, deliberately. The identity above converges on the
      // league's record; the NAME on the row stays the provider's, so the row
      // still carries the representation it was published under. Identity and
      // provenance are different jobs and this row does both.
      player_name: normalizeName(player).display || player,
      team: s.team || base.team || null,
      opponent: s.opponent || base.opponent || null,
      stat,
      line,
      side,

      book: s.book || base.book || null,
      book_odds: intOrNull(s.book_odds),
      over_odds: intOrNull(base.over_odds),
      under_odds: intOrNull(base.under_odds),
      fair_odds: intOrNull(s.fair_odds),
      fair_prob: numOrNull(s.fair_prob),
      overround: numOrNull(s.overround),
      devig_method: s.devig_method || null,

      grade: s.grade || null,
      grade_11: s._grade_11 || null,
      confidence: numOrNull(s.confidence),
      confidence_basis: s.confidence_basis || null,
      p_win: numOrNull(s.p_win),
      ev_pct: numOrNull(s.ev_pct),
      projection: numOrNull(s.projection),
      edge_pct: numOrNull(s.edge_pct),
      takeable: boolOrNull(s.takeable),
      value: boolOrNull(s.value),
      archetype: s.archetype || null,

      refused,
      // Set TRUE only by the collector's publication signal (see createCollector).
      published: false,
      // CANONICAL EVENT IDENTITY. Declared on every row; null when the sport
      // has no resolver or the event could not be resolved. `game_id` below
      // stays as the LEGACY DERIVED label — useful for diagnostics and
      // compatibility, never authoritative for identity.
      canonical_event_id: (s.canonical_event_id ?? base.canonical_event_id) ?? null,
      event_identity_source: (s.event_identity_source ?? base.event_identity_source) ?? null,
      event_identity_method: (s.event_identity_method ?? base.event_identity_method) ?? null,
      event_identity_version: (s.event_identity_version ?? base.event_identity_version) ?? null,
      event_occurrence: (s.event_occurrence ?? base.event_occurrence) ?? null,
      refusal_reason: refused
        ? (s.suppressed_reason || (s.insufficient_data ? 'insufficient_data' : 'no_grade'))
        : null,

      // The counterfactual enabler. Absent on pre-feature refusals (the juice
      // gate runs before features are computed) — honestly null, never faked.
      features: s._features && Object.keys(s._features).length ? s._features : null,

      // FIX A5 — the RAW inputs the hits factors read, frozen at grade time so a
      // re-audit reads evidence instead of reconstructing context. Inputs only:
      // the multiplier is recomputable from them and is deliberately not stored.
      // Null on every non-hits row and on any row with no factor context.
      factor_inputs: s.factor_inputs || null,

      // The SHADOW CHAIN read. Declared here (always present, usually null) so
      // every row in a batch carries the same keys — PostgREST builds a bulk
      // insert from the FIRST row's shape, so a column that appears only on some
      // rows is silently dropped for the whole batch. Filled by
      // `mergeChainShadow` after enrichment; never read by anything served.
      chain_shadow: null,

      // The PROBABILITY CONTRACT shadow — what the certified serving contract
      // WOULD serve, beside what was actually served. Declared always, for the
      // same first-row-shape reason as chain_shadow. Filled by
      // `mergeProbabilityContract`; SHADOW ONLY, read by nothing served.
      probability_contract: null,
    });
  }
  return rows;
}

/** A collector to hand to gradeAndCacheSlate's `onGraded` hook. */
function createCollector(ctx) {
  const rows = [];
  // Index by (player|stat|line|side) so the publication signal can find the row
  // it already collected without re-deriving the winner rule.
  const index = new Map();
  const keyOf = (r) => [r.player_key, r.stat, r.line, r.side].join('|');
  return {
    rows,
    onGraded(base, sides) {
      try {
        const made = rowsFromSides(base, sides, ctx);
        for (const r of made) index.set(keyOf(r), r);
        rows.push(...made);
      } catch { /* collection never affects grading */ }
    },
    /**
     * PUBLICATION SIGNAL — fired only for the side that actually reaches the
     * slate.
     *
     * ── WHY THIS EXISTS ──────────────────────────────────────────────────
     * `onGraded` fires with BOTH sides, graded AND refused, BEFORE any
     * filtering. Only the higher-confidence graded side becomes the served
     * Read. MEASURED on mlb 2026-08-26: of 13,012 collected rows, 3,859 were
     * refusals and only 4,569 matched a prop that reached the ledger — 8,443
     * (64.9%) describe a state the user was never shown.
     *
     * Nothing on the row said which was which, so treating every capture as a
     * published claim would have built "publication history" for model activity
     * that was never published. This marks the difference at the one place that
     * knows it: the moment the winner is chosen.
     */
    onPublished(base, winner) {
      try {
        if (!winner) return;
        const made = rowsFromSides(base, [winner], ctx);
        for (const r of made) {
          const hit = index.get(keyOf(r));
          // `published` alone. A companion `published_side` was written here
          // and is NOT a model_snapshots column — it made PostgREST reject the
          // ENTIRE retention batch with a 400, silently, for every sport. The
          // side is already on the row (`side`), so the flag was redundant as
          // well as invalid.
          if (hit) { hit.published = true; }
        }
      } catch { /* signalling never affects grading */ }
    },
  };
}


/**
 * DUAL-WRITE: attach append-only Read lineage to rows about to be persisted.
 *
 * ── WHY THIS IS BEST-EFFORT AND WHY IT MUST DECLARE EVERY KEY ────────────
 * Retention is already best-effort relative to the ledger; lineage sits one
 * layer further out, so a lineage failure must never cost a retention row and
 * never reach the grade. Every failure path below leaves the row persistable
 * with NULL lineage, which reads as "unknown" — the honest value.
 *
 * Lineage keys are declared on EVERY row even when unresolved. PostgREST builds
 * a bulk insert from the FIRST row's shape, so a key present on only some rows
 * is dropped for the whole batch — the same defect that silently killed
 * retention for three days when `chain_shadow` was missing from the schema.
 *
 * NOT AUTHORITATIVE. Nothing reads these columns to serve a product surface;
 * this records truth in parallel so it can be compared against the live path
 * before any authority changes.
 */
const LINEAGE_KEYS = Object.freeze([
  'read_id', 'read_natural_key', 'claim_digest', 'revision_ordinal',
  'supersedes_id', 'recaptures_id', 'lineage_action', 'lineage_state',
  'lineage_version', 'change_type', 'claim_schema_version',
  'digest_algorithm_version',
]);

/**
 * ── WHAT A COMPLETED LINEAGE ACTION IS ───────────────────────────────────
 * A row carrying `read_natural_key` is NOT lineage history. The key is stamped
 * on every candidate BEFORE the family lookup runs, so a failed resolution
 * leaves it behind on a row that never became an action.
 *
 * A completed action is a row that answers all four questions the chronology
 * asks of it: WHICH Read (`read_id`), WHAT it did (`lineage_action`), WHAT it
 * claimed (`claim_digest` + the two version stamps that make the digest
 * interpretable), and WHERE it sits (`revision_ordinal`). Miss any one and the
 * row cannot serve as history, a head, a parent or a recapture predecessor.
 *
 * This is stated as what an action IS — not as a rule shaped to exclude one
 * known batch of failed rows.
 */
const VALID_LINEAGE_ACTION_FIELDS = Object.freeze([
  'read_id', 'read_natural_key', 'lineage_action', 'claim_digest',
  'revision_ordinal', 'lineage_state', 'lineage_version',
  'claim_schema_version', 'digest_algorithm_version',
]);

/** Does this physical row qualify as a completed lineage action? */
function isValidLineageAction(row) {
  if (!row) return false;
  for (const f of VALID_LINEAGE_ACTION_FIELDS) {
    const v = row[f];
    if (v === null || v === undefined || v === '') return false;
  }
  return true;
}

/**
 * ── WHY THE FAMILY IS FETCHED BY (sport, game_date) ──────────────────────
 * `readLineage.readNaturalKey` builds the key as
 *   sport | game_date | player_key | stat | side | line [| #event]
 * so SPORT AND GAME_DATE ARE COMPONENTS OF THE KEY ITSELF. Two rows sharing a
 * natural key necessarily share both. Restricting the lookup to the (sport,
 * game_date) pairs present in the requested keys is therefore LOSSLESS BY
 * CONSTRUCTION, not an optimisation that trades recall for speed. A test
 * asserts the derivation against the key builder so the two cannot drift.
 *
 * That bound is what makes the read scale with THE SLATE rather than with
 * history: one date's valid actions, however many years of chronology sit
 * behind it.
 *
 * WHY NOT KEEP THE IN-LIST. Measured 2026-08-28: `read_natural_key` has NO
 * pg_stats row at all (the last autoanalyze predates the column ever being
 * populated), so the planner falls back to a default per-value selectivity.
 * At 100 keys it estimated 172,409 rows and chose a sequential scan of 344,818
 * — 8.5s, then 57014. The plan for this shape is
 * `Index Scan using model_snapshots_lineage_family_idx, cost 0.28..1.92`,
 * and it does not depend on an estimate being good.
 */
function familyScopesFrom(naturalKeys) {
  const scopes = new Map();
  for (const k of naturalKeys || []) {
    const parts = String(k).split('|');
    const sport = parts[0];
    const gameDate = parts[1];
    if (!sport || !gameDate) continue;
    scopes.set(`${sport}|${gameDate}`, { sport, game_date: gameDate });
  }
  return [...scopes.values()];
}

/** Claim fields the resolver needs from EXISTING rows to classify a change. */
const LINEAGE_FETCH_CLAIM = Object.freeze([
  'canonical_event_id',
  'line', 'side', 'book', 'over_odds', 'under_odds',
  'p_win', 'grade', 'confidence', 'projection', 'edge_pct', 'ev_pct',
  'takeable', 'value', 'fair_odds', 'fair_prob', 'confidence_basis',
  'refused', 'refusal_reason',
]);

function blankLineage() {
  const o = {};
  for (const k of LINEAGE_KEYS) o[k] = null;
  return o;
}

/**
 * ── DUAL-WRITE FAILURE CONTRACT ──────────────────────────────────────────
 * Lineage lives on the SAME ROW as the retention record and is attached before
 * the single upsert that writes it. That is not a convenience; it is what makes
 * two of the four failure quadrants structurally impossible:
 *
 *   legacy OK  + lineage OK      one insert carries both.
 *   legacy OK  + lineage FAILS   the row still persists with NULL lineage. The
 *                                claim is retained; only its position in the
 *                                chronology is unknown, and `out.lineage.error`
 *                                plus the not_published/refused counters make
 *                                the gap measurable rather than silent.
 *   legacy FAILS + lineage OK    IMPOSSIBLE. There is no separate lineage
 *                                write, so a failed retention insert cannot
 *                                leave behind a lineage record claiming a Read
 *                                was published. This is the quadrant that would
 *                                manufacture false publication history, and the
 *                                write ordering removes it rather than guarding
 *                                against it.
 *   legacy FAILS + lineage n/a   nothing is written at all.
 *
 * Ordering matters and is deliberate: resolve first, then one write. A separate
 * lineage table written after the fact would reintroduce the impossible
 * quadrant as a real one.
 */
async function attachLineage(rows, deps = {}) {
  const out = {
    attempted: Array.isArray(rows) ? rows.length : 0,
    origins: 0, revisions: 0, recaptures: 0, forks: 0, refused: 0, unresolved: 0,
    // A capture that was never the served Read is NOT a lineage failure. It is
    // counted separately so the parity gap stays legible: lumping it into
    // `refused` would make a healthy slate look broken.
    not_published: 0,
    change_types: {},
    error: null,
  };
  const list = Array.isArray(rows) ? rows : [];
  // Declare the keys first, unconditionally. Even a total failure leaves a
  // persistable batch shape.
  for (const r of list) Object.assign(r, blankLineage());
  if (list.length === 0) return out;

  try {
    const lineage = deps.lineage || require('./read/readLineage');
    const mintReadId = deps.mintReadId || (() => require('crypto').randomUUID());

    const keyed = [];
    for (const r of list) {
      const key = lineage.readNaturalKey(r);
      if (!key) { out.unresolved += 1; continue; }
      r.read_natural_key = key;
      keyed.push(r);
    }
    if (keyed.length === 0) return out;

    // ONE bounded read of the existing families for these natural keys.
    const keys = [...new Set(keyed.map((r) => r.read_natural_key))];
    const fetchExisting = deps.fetchExisting || (async (naturalKeys) => {
      const getClient = deps.getClient || require('../utils/supabase').getSupabaseServiceClient;
      const supabase = getClient();
      if (!supabase) return null;
      const { paginate } = require('../utils/safePaginate');
      const columns = ['id', 'read_id', 'read_natural_key', 'game_id', 'claim_digest',
        'revision_ordinal', 'lineage_action', 'supersedes_id', 'captured_at',
        'lineage_state', 'lineage_version', 'claim_schema_version',
        'digest_algorithm_version', ...LINEAGE_FETCH_CLAIM].join(', ');
      const wanted = new Set(naturalKeys);
      const found = [];
      out.lookup = { scopes: 0, rows_scanned: 0, valid_actions: 0, invalid_excluded: 0 };
      for (const scope of familyScopesFrom(naturalKeys)) {
        // ONE index-backed range per (sport, game_date), walked with the
        // repository's keyset paginator — never a hand-rolled second walk, and
        // it THROWS rather than treating a failed page as end-of-data.
        // eslint-disable-next-line no-await-in-loop
        const rows = await paginate(() => supabase
          .from('model_snapshots')
          .select(columns)
          .eq('sport', scope.sport)
          .eq('game_date', scope.game_date)
          .not('lineage_action', 'is', null), { key: 'id', label: 'attachLineage.fetchExisting' });
        out.lookup.scopes += 1;
        out.lookup.rows_scanned += rows.length;
        for (const r of rows) {
          if (!wanted.has(r.read_natural_key)) continue;
          // The predicate is applied in code as well as in the query. The query
          // narrows what travels; this decides what COUNTS, and a row that half
          // resolved must never be mistaken for history by either.
          if (!isValidLineageAction(r)) { out.lookup.invalid_excluded += 1; continue; }
          out.lookup.valid_actions += 1;
          found.push(r);
        }
      }
      return found;
    });

    const existing = await fetchExisting(keys);
    if (existing === null) return out; // no database configured — leave NULL
    // Second line of defence: an injected or future fetcher must not be able to
    // smuggle a half-resolved row into the chronology either.
    const validExisting = existing.filter(isValidLineageAction);
    out.invalid_rows_excluded = existing.length - validExisting.length;

    const byKey = new Map();
    for (const e of validExisting) {
      // The prior claim rides alongside so `classifyChange` can say WHY the
      // published state advanced, not merely that the digest differs.
      const claim = {};
      for (const f of LINEAGE_FETCH_CLAIM) claim[f] = e[f];
      const entry = { ...e, claim };
      if (!byKey.has(e.read_natural_key)) byKey.set(e.read_natural_key, []);
      byKey.get(e.read_natural_key).push(entry);
    }

    for (const r of keyed) {
      const res = lineage.resolveLineage({
        candidate: r,
        existing: byKey.get(r.read_natural_key) || [],
        mintReadId,
      });
      if (!res.ok) {
        if (res.refused === 'not_published') out.not_published += 1;
        else if (res.action === lineage.LINEAGE_ACTION.FORK_DETECTED) out.forks += 1;
        else out.refused += 1;
        // A refusal leaves NULL lineage on a row that is still persisted. The
        // claim is retained; only its position in the chronology is unknown.
        continue;
      }
      r.read_id = res.read_id;
      r.claim_digest = res.claim_digest;
      r.revision_ordinal = res.revision_ordinal;
      r.supersedes_id = res.supersedes_id ?? null;
      r.recaptures_id = res.recaptures_id ?? null;
      r.lineage_action = res.action;
      r.lineage_state = res.lineage_state;
      r.lineage_version = res.lineage_version;
      r.change_type = res.change_type || null;
      r.claim_schema_version = res.claim_schema_version || null;
      r.digest_algorithm_version = res.digest_algorithm_version || null;
      if (res.change_type) {
        out.change_types[res.change_type] = (out.change_types[res.change_type] || 0) + 1;
      }

      if (res.action === lineage.LINEAGE_ACTION.ORIGIN) out.origins += 1;
      else if (res.action === lineage.LINEAGE_ACTION.REVISION) out.revisions += 1;
      else if (res.action === lineage.LINEAGE_ACTION.RECAPTURE) out.recaptures += 1;

      // Newly minted read_ids must be visible to later rows in the SAME batch,
      // or two rows of one Read would each mint an id and fork it immediately.
      const fam = byKey.get(r.read_natural_key) || [];
      const claim = {};
      for (const f of LINEAGE_FETCH_CLAIM) claim[f] = r[f];
      fam.push({
        id: null, read_id: r.read_id, read_natural_key: r.read_natural_key,
        game_id: r.game_id, claim_digest: r.claim_digest,
        revision_ordinal: r.revision_ordinal, lineage_action: r.lineage_action,
        supersedes_id: r.supersedes_id, captured_at: r.captured_at, claim,
      });
      byKey.set(r.read_natural_key, fam);
    }
  } catch (e) {
    out.error = e && e.message ? e.message : String(e);
  }

  // ── FAILURE ATOMICITY ───────────────────────────────────────────────────
  // `read_natural_key` is stamped on every candidate BEFORE the family lookup,
  // so a lookup that throws leaves it behind on a row that never became an
  // action. That is the shape the 2026-08-28 scheduled canary wrote 1,119 times.
  //
  // It is LINEAGE FAMILY IDENTITY, not publication provenance, so a failed
  // attempt has no claim to it. `publication_id` / `published_at` are NOT
  // touched here: the slate really was published, and erasing that to make the
  // failure look tidier would delete a true fact to hide a false one.
  //
  // The result: a failed row carries no lineage-specific state at all, so it
  // cannot be mistaken for history by a future resolver, a query, or a reader.
  let cleared = 0;
  for (const r of list) {
    if (isValidLineageAction(r)) continue;
    if (LINEAGE_KEYS.some((k) => r[k] !== null && r[k] !== undefined)) cleared += 1;
    Object.assign(r, blankLineage());
  }
  out.incomplete_cleared = cleared;
  return out;
}

/** The unique index that prevents a forked chain, named so the guard is legible. */
const SUPERSEDES_CONSTRAINT = 'model_snapshots_supersedes_unique';
const FORK_RETRY_LIMIT = 2;

function isSupersedesConflict(error) {
  if (!error) return false;
  const m = `${error.message || ''} ${error.details || ''}`;
  return m.includes(SUPERSEDES_CONSTRAINT) || (error && error.code === '23505' && m.includes('supersedes'));
}

/**
 * Recover a batch that lost a supersedes race.
 *
 * Bounded on purpose: two attempts, then an explicit failure. An unbounded loop
 * against a writer that keeps winning would spin forever, and the correct answer
 * after a couple of misses is to report the gap rather than keep trying.
 *
 * Sequence per attempt: re-resolve the batch against the CURRENT head, then
 * write. Re-resolution is what makes this safe -- if the rival already published
 * an identical claim, `attachLineage` returns RECAPTURE and the row lands
 * idempotently; if our claim is still materially different it appends after the
 * new head instead of trying to supersede a parent that is no longer the head.
 */
async function recoverFromFork(chunk, deps = {}) {
  const out = { recovered: false, written: 0, attempts: 0, error: null };
  const supabase = deps.supabase;
  for (let attempt = 1; attempt <= FORK_RETRY_LIMIT; attempt += 1) {
    out.attempts = attempt;
    try {
      // Clear stale lineage so re-resolution sees the row as a fresh candidate.
      for (const r of chunk) Object.assign(r, blankLineage());
      // eslint-disable-next-line no-await-in-loop
      await attachLineage(chunk, deps);
      // eslint-disable-next-line no-await-in-loop
      const { error } = await upsertSnapshotChunk(supabase, chunk);
      if (!error) { out.recovered = true; out.written = chunk.length; return out; }
      if (!isSupersedesConflict(error)) { out.error = error.message; return out; }
      out.error = error.message;
    } catch (e) {
      out.error = e && e.message ? e.message : String(e);
      return out;
    }
  }
  return out;
}

/**
 * COMMIT PUBLICATION - the only place a claim becomes "published".
 *
 * -- WHY THIS IS SEPARATE FROM THE CAPTURE WRITE -------------------------
 * The authoritative served slate is ONE atomic Redis write,
 * `cacheSet('snapshot:{sport}:latest', snapshot)`. Retention persists BEFORE
 * that write (measured: persistRetention at snapshotService:1137, the slate
 * write at :1152), and the winner is selected earlier still. So neither capture
 * nor winner-selection can mean "published":
 *
 *   winner selected      -> intended for the slate
 *   retention persisted  -> the capture is on the record
 *   REDIS WRITE SUCCEEDS -> the claim was actually made available   <-- HERE
 *
 * Setting the marker any earlier lets lineage assert a publication that a failed
 * Redis write never made. That is the one thing lineage must never do.
 *
 * -- PUBLICATION IS SLATE-LEVEL, BECAUSE THE WRITE IS --------------------
 * The whole envelope commits or none of it does, so every served row shares one
 * `publication_id` and one `published_at`. Modelling per-row publication would
 * claim a granularity the transport does not have.
 *
 * -- FAILURE DIRECTION IS DELIBERATE ------------------------------------
 * If this update fails after a successful Redis write, rows stay
 * `published: false` with NULL lineage. The record then UNDERSTATES what was
 * served, which is recoverable and observable. The opposite error - claiming a
 * publication that did not happen - is not.
 */
async function commitPublication(spec, deps = {}) {
  const s = spec || {};
  const out = {
    publication_id: s.publicationId || null,
    published_at: s.publishedAt || null,
    candidates: 0, published: 0, skipped: false, error: null, lineage: null,
  };
  const served = Array.isArray(s.rows) ? s.rows.filter((r) => r && r.published === true) : [];
  out.candidates = served.length;
  if (served.length === 0) return out;

  try {
    const getClient = deps.getClient || require('../utils/supabase').getSupabaseServiceClient;
    const supabase = getClient();
    if (!supabase) { out.skipped = true; return out; }

    for (const r of served) {
      r.published_at = out.published_at;
      r.publication_id = out.publication_id;
    }
    // Lineage resolves ONLY over confirmed-published rows.
    if (deps.lineage !== false) {
      out.lineage = await attachLineage(served, { ...deps, getClient });
    }

    const CHUNK = 250;
    for (let i = 0; i < served.length; i += CHUNK) {
      const chunk = served.slice(i, i + CHUNK);
      // eslint-disable-next-line no-await-in-loop
      const { error } = await upsertSnapshotChunk(supabase, chunk);
      if (!error) { out.published += chunk.length; continue; }

      // ── CONCURRENCY RECOVERY ────────────────────────────────────────────
      // `model_snapshots_supersedes_unique` rejects a second row superseding the
      // same parent. That constraint is the authority against a forked history,
      // and hitting it means another writer advanced the chain between our
      // resolve and our write. The loser must not silently drop a materially new
      // published state, and must not loop.
      if (!isSupersedesConflict(error)) { out.error = error.message; break; }
      // eslint-disable-next-line no-await-in-loop
      const rec = await recoverFromFork(chunk, { ...deps, getClient, supabase });
      out.conflicts = (out.conflicts || 0) + 1;
      if (rec.recovered) {
        out.recovered = (out.recovered || 0) + 1;
        out.published += rec.written;
      } else {
        out.recovery_failed = (out.recovery_failed || 0) + 1;
        out.error = rec.error || 'fork recovery exhausted';
        break;
      }
    }
  } catch (e) {
    out.error = e && e.message ? e.message : String(e);
  }

  // ── EXACT PARITY-GAP IDENTITY ──────────────────────────────────────────
  // "lineage failed" is not an answer. When the product published successfully
  // and the record did not, the system must be able to say WHICH EXACT SERVED
  // CLAIM is missing, without re-deriving it from player/stat/line/date.
  //
  // Everything needed to recover it deterministically is captured here from the
  // in-memory rows that were actually served.
  if (out.error || (out.lineage && out.lineage.error) || out.published < out.candidates) {
    out.parity_gap = Object.freeze({
      sport: served[0] ? served[0].sport : null,
      publication_id: out.publication_id,
      published_at: out.published_at,
      attempted_at: (deps.now || (() => new Date().toISOString()))(),
      reason: out.error || (out.lineage && out.lineage.error) || 'partial_commit',
      missing_count: out.candidates - out.published,
      // The exact rows, by the identity the retention table itself keys on.
      missing: Object.freeze(served.slice(out.published).map((r) => Object.freeze({
        snapshot_id: r.snapshot_id || null,
        player_key: r.player_key || null,
        stat: r.stat || null,
        line: r.line === undefined ? null : r.line,
        side: r.side || null,
        canonical_event_id: r.canonical_event_id || null,
        read_id: r.read_id || null,
        read_natural_key: r.read_natural_key || null,
        claim_digest: r.claim_digest || null,
        captured_at: r.captured_at || null,
      }))),
    });
  }
  return out;
}

/**
 * Persist rows. Chunked, upsert-on-conflict-ignore so a retried cycle can never
 * duplicate. No-ops (successfully) without Supabase env, so tests and local dev
 * never touch a database.
 */
async function persist(rows, deps = {}) {
  const out = { attempted: Array.isArray(rows) ? rows.length : 0, written: 0, skipped: false, error: null };
  if (!out.attempted) return out;
  try {
    const getClient = deps.getClient || require('../utils/supabase').getSupabaseServiceClient;
    const supabase = getClient();
    if (!supabase) { out.skipped = true; return out; }
    // NOTE: lineage is NOT resolved here any more.
    //
    // Capture happens BEFORE the authoritative Redis slate write
    // (`snapshot:{sport}:latest`), so resolving lineage at this point would
    // record a published claim for a slate that may never be served. Publication
    // is committed by `commitPublication()` after that write succeeds.
    //
    // Rows are persisted with `published: false` and NULL lineage, which is the
    // truthful state of a capture that has not yet been served.
    const CHUNK = 250;
    for (let i = 0; i < rows.length; i += CHUNK) {
      const chunk = rows.slice(i, i + CHUNK);
      const res = await upsertSnapshotChunk(supabase, chunk, { ignoreDuplicates: true });
      if (res.fellBack) out.legacy_conflict_fallback = true;
      const { error } = res;
      if (error) { out.error = error.message; break; }
      out.written += chunk.length;
    }
  } catch (e) {
    out.error = e && e.message ? e.message : String(e);
  }
  return out;
}

/**
 * Fill archetype / team / opponent onto collected rows from the ENRICHED grades.
 *
 * Retention collects at GRADE time, which is the only moment the feature vector
 * exists — but archetype/team/opponent are attached later, during snapshot
 * enrichment. Capturing at grade time alone left all three permanently null,
 * which specifically blocks the archetype-baselined metrics work.
 *
 * CONTRACT: this ONLY fills those three fields. It must never touch `features`
 * or any model output — grade-time values are the record, and enrichment must
 * not rewrite history. Unmatched rows (e.g. refusals, which never reach the
 * enriched slate) pass through untouched with the fields left null: honestly
 * absent, not guessed.
 */
function mergeEnrichment(rows, enrichedGrades) {
  if (!Array.isArray(rows) || !rows.length) return rows || [];
  const byPlayer = new Map();
  for (const g of enrichedGrades || []) {
    const raw = g && (g.player || g.player_name);
    if (!raw) continue;
    const k = nameKey(raw);
    // First enriched grade per player wins; archetype/team are player-level.
    if (!byPlayer.has(k)) {
      byPlayer.set(k, {
        archetype: g.archetype ?? null,
        team: g.team ?? null,
        opponent: g.opponent ?? null,
      });
    }
  }
  return rows.map((r) => {
    const e = byPlayer.get(r.player_key);
    if (!e) return r;
    return {
      ...r,
      archetype: r.archetype ?? e.archetype ?? null,
      team: r.team ?? e.team ?? null,
      opponent: r.opponent ?? e.opponent ?? null,
    };
  });
}

/**
 * Attach the SHADOW CHAIN read to collected rows — the (chain_p, counter_p,
 * outcome) triple's first two thirds.
 *
 * Like `mergeEnrichment` this fills ONE field and touches nothing else. It runs
 * later than grade time for the same structural reason the archetype does: the
 * chain needs the statcast rows and park factors the enrichment pass loaded, and
 * pulling that forward into the grader would put per-prop I/O on the serving
 * path.
 *
 * THE SIDE ALIGNMENT IS THE LOAD-BEARING PART. The chain computes P(over the
 * line); `p_win` on the row is expressed for the graded SIDE. Storing the raw
 * over-probability against an under row's `p_win` would invert every comparison
 * made from it afterwards, silently — so `alignToSide` is given the row's own
 * side and the row's own counter probability, and both halves of the triple end
 * up pointing the same way. `outcome` is written by the ordinary settle pass and
 * is already side-aligned, which completes it.
 *
 * A row the chain could not read is left NULL. It is not a zero probability and
 * not an average hitter — the chain refusing to read someone is a fact worth
 * keeping, and a fabricated third of a triple would poison the adjudication this
 * column exists to enable.
 */
/**
 * Attach the SHADOW CHAIN read to collected rows — the (chain_p, counter_p,
 * outcome) triple's first two thirds.
 *
 * Like `mergeEnrichment` this fills ONE field and touches nothing else. It runs
 * later than grade time for the same structural reason the archetype does: the
 * chain needs the statcast rows and park factors the enrichment pass loaded, and
 * pulling that forward into the grader would put per-prop I/O on the serving
 * path.
 *
 * THE SIDE ALIGNMENT IS THE LOAD-BEARING PART. The chain computes P(over the
 * line); `p_win` on the row is expressed for the graded SIDE. Storing the raw
 * over-probability against an under row's `p_win` would invert every comparison
 * made from it afterwards, silently — so `alignToSide` is given the row's own
 * side and the row's own counter probability, and both halves of the triple end
 * up pointing the same way. `outcome` is written by the ordinary settle pass and
 * is already side-aligned, which completes it.
 *
 * A row the chain could not read is left NULL. It is not a zero probability and
 * not an average hitter — the chain refusing to read someone is a fact worth
 * keeping, and a fabricated third of a triple would poison the adjudication this
 * column exists to enable.
 */
/**
 * PROBABILITY CONTRACT SHADOW.
 *
 * Records, per row: the raw model belief, what the certified contract would
 * serve, the state, the estimator identity, and what EV/Kelly/VALUE would be
 * under the actionability law. It writes to its own column and mutates nothing
 * a user sees — `p_win`, `confidence`, `grade`, `ev_pct`, `value` and
 * `takeable` on the row are untouched.
 *
 * The raw probability is ALWAYS carried, including on refusals: it is model
 * evidence, and a row that records only the refusal cannot be re-adjudicated.
 */
function mergeProbabilityContract(rows, contract) {
  if (!Array.isArray(rows) || !rows.length) return rows || [];
  if (!contract || typeof contract.resolve !== 'function') return rows;
  const pc = require('./model/probabilityContract');

  return rows.map((r) => {
    let res;
    try {
      // The ROW's sport and stat travel with it. Omitting them let the
      // resolver substitute its own and calibrate every stat as hits.
      res = contract.resolve({
        sport: r.sport, stat: r.stat,
        model_version: r.model_version, p_win: numOrNull(r.p_win),
      });
    } catch { return r; }
    if (!res) return r;
    let derived;
    // The SIDE'S price. A retention row carries book_odds plus both sides'
    // prices; using the wrong side would price the opposite bet.
    const sideOdds = r.book_odds != null ? r.book_odds
      : (String(r.side) === 'under' ? r.under_odds : r.over_odds);
    try { derived = pc.derivedClaims(res, sideOdds); } catch { derived = null; }
    return {
      ...r,
      probability_contract: {
        raw_model_probability: res.raw_model_probability,
        served_probability: res.served_probability,
        probability_state: res.probability_state,
        estimator_type: res.estimator_type,
        estimator_version: res.estimator_version,
        certification_version: res.certification_version,
        model_version: res.model_version,
        reason: res.reason,
        // WHICH FROZEN ARTIFACT PRODUCED THIS — its IDENTITY, not its body.
        // The curve is committed in the repository and addressable by
        // `artifact_id`, so embedding it on every row would store the same ~900
        // bytes thousands of times per snapshot to say something the id already
        // says. `source_digest` pins the exact observation set it was fitted
        // on, so the row remains reconstructable.
        artifact: res.artifact ? {
          artifact_id: res.artifact.artifact_id,
          procedure_version: res.artifact.procedure_version,
          model_version: res.artifact.model_version,
          fit_as_of: res.artifact.fit_as_of,
          training_cutoff: res.artifact.training_cutoff,
          fit_n: res.artifact.fit_n,
          source_digest: res.artifact.source_digest,
          knot_digest: res.artifact.knot_digest,
          served_curve_digest: res.artifact.served_curve_digest,
          certified_bands: res.artifact.certified_bands,
          stage: res.artifact.stage,
          servable: res.artifact.servable,
        } : null,
        derived: derived ? {
          available: derived.available,
          ev_pct: derived.ev_pct,
          kelly_pct: derived.kelly ? derived.kelly.pct : null,
          value: derived.value,
        } : null,
        // SHADOW. Nothing here has been served to anyone.
        servable: false,
      },
    };
  });
}

function mergeChainShadow(rows, shadow) {
  if (!Array.isArray(rows) || !rows.length) return rows || [];
  const byKey = shadow && shadow.byKey;
  if (!byKey || typeof byKey.get !== 'function') return rows;
  const cs = require('./model/chainShadow');

  return rows.map((r) => {
    const block = byKey.get(cs.shadowKey(r.player_key, r.stat, r.line));
    if (!block) return r;
    const aligned = cs.alignToSide(block, r.side, r.p_win);
    return aligned ? { ...r, chain_shadow: aligned } : r;
  });
}

function newSnapshotId() {
  return crypto.randomUUID();
}

/* ------------------------------------------------------------------ *
 * RETENTION CONFLICT TARGET — event-aware, mixed-fleet safe
 *
 * SEMANTIC IDENTITY. Two outbound rows are the SAME retention proposition
 * within one cycle when they share: the cycle, the EVENT, the participant, the
 * stat, the line and the side. Provider/book is deliberately NOT part of it —
 * collapsing books is `dedupeProps`'s actual job, and the price anchor is
 * chosen later.
 *
 * The EVENT component uses the strongest truthful label available and never
 * fabricates one: `canonical_event_id` where a sport has a resolver (MLB, where
 * `admitForGrading` makes it non-null for every row that can reach retention),
 * and `game_id` otherwise (NOT NULL in the schema, and the only event label
 * sports without a resolver possess). Both columns are in the identity, so the
 * weaker label still discriminates where the stronger one is absent.
 *
 * NULLS NOT DISTINCT is load-bearing. `canonical_event_id` is NULL for every
 * non-MLB row, and under PostgreSQL's DEFAULT null semantics two NULLs are
 * DISTINCT — measured: the same NBA proposition inserted twice produced TWO
 * rows, i.e. every retry would duplicate for ever. With NULLS NOT DISTINCT the
 * same test produces one row and retry idempotency holds.
 *
 * MIXED-FLEET SAFETY. A rollout serves old and new containers at once
 * (measured: 11 of 12 probes new, 1 old). The two writers need different
 * indexes, and no schema state satisfies both:
 *
 *   old index present  -> old writer works; new writer ERRORS 23505 on a
 *                         doubleheader (the legacy index rejects a row the
 *                         event-aware identity considers distinct)
 *   old index dropped  -> new writer works; old writer ERRORS 42P10
 *
 * A bare `ON CONFLICT DO NOTHING` would have bridged this, but PostgREST does
 * NOT emit one: `ignoreDuplicates` without `onConflict` was measured raising a
 * real duplicate-key error, so that bridge does not exist through this client.
 *
 * So the writer bridges it instead. It targets the event-aware identity and, on
 * exactly the two errors that mean "the schema is not in the state I expect",
 * retries the SAME chunk on the legacy target. A failed chunk rolls back
 * atomically (measured: 0 rows), so the retry cannot double-write. The result
 * is a writer that is correct in every schema state:
 *
 *   legacy only  -> 42P10  -> legacy target  -> legacy semantics, no outage
 *   both present -> 23505  -> legacy target  -> legacy semantics, no outage
 *   new only     -> primary succeeds         -> doubleheaders kept
 *
 * The fallback is a BRIDGE, not a resting place: while it fires, doubleheader
 * rows are still lost, and `outbound_collision_count` still reports it.
 * ------------------------------------------------------------------ */

const LEGACY_CONFLICT_INDEX = 'model_snapshots_cycle_prop_uniq';
const LEGACY_CONFLICT = 'snapshot_id,player_key,stat,line,side';
const RETENTION_CONFLICT = 'snapshot_id,game_id,canonical_event_id,player_key,stat,line,side';

/**
 * Is this error "the schema is not in the state the event-aware target
 * expects"? Deliberately narrow: a supersedes conflict is also a 23505, and
 * swallowing THAT would destroy the forked-history guard, so the legacy index
 * must be named.
 */
function isLegacyConflictBlock(error) {
  if (!error) return false;
  const code = String(error.code || '');
  const msg = String(error.message || '');
  if (code === '42P10' || /no unique or exclusion constraint matching/i.test(msg)) return true;
  return (code === '23505' || /duplicate key value/i.test(msg)) && msg.includes(LEGACY_CONFLICT_INDEX);
}

/**
 * One chunk write. Returns the error (never throws) plus which target actually
 * carried it, so a caller can report that the bridge is still in use.
 */
async function upsertSnapshotChunk(supabase, chunk, opts = {}) {
  const first = await supabase.from('model_snapshots')
    .upsert(chunk, { onConflict: RETENTION_CONFLICT, ...opts });
  if (!first.error) return { error: null, target: RETENTION_CONFLICT, fellBack: false };
  if (!isLegacyConflictBlock(first.error)) {
    return { error: first.error, target: RETENTION_CONFLICT, fellBack: false };
  }
  const second = await supabase.from('model_snapshots')
    .upsert(chunk, { onConflict: LEGACY_CONFLICT, ...opts });
  return { error: second.error || null, target: LEGACY_CONFLICT, fellBack: true };
}

/* ------------------------------------------------------------------ *
 * MATERIALIZATION IDENTITY
 *
 * TRANSPORT COMPLETE and MATERIALIZATION COMPLETE are different facts.
 *
 * The write is `upsert(..., { onConflict: RETENTION_CONFLICT, ignoreDuplicates:
 * true })`. Until migration 049 retires it, the LEGACY index
 *   model_snapshots_cycle_prop_uniq UNIQUE (snapshot_id, player_key, stat, line, side)
 * is still enforced and the writer falls back to it (see the bridge above)
 * so two outbound rows sharing that tuple collapse to ONE stored row and the
 * loser is discarded WITHOUT AN ERROR. `written` counts rows in committed
 * chunks, so transport reports both as written and the status reads COMPLETE.
 *
 * `snapshot_id` IS in the identity and is a fresh UUID per cycle, so a row can
 * never be suppressed by a PREVIOUS cycle — append-only chronology across
 * cycles is safe. `canonical_event_id` is NOT in the identity, so two DISTINCT
 * events inside ONE cycle (a doubleheader: same hitter, same stat, same line,
 * both games) DO collide.
 *
 * No duplicate is intentional here: `rowsFromSides` emits one row per (base,
 * side) and bases are already deduped by event::player::stat::line. Any
 * duplicate identity in an outbound payload is therefore an UNEXPECTED
 * COLLISION, and a cohort carrying one does not qualify as evidence.
 *
 * The conflict identity is NOT changed here. This only makes the loss visible.
 * ------------------------------------------------------------------ */

/**
 * The exact columns the database conflict target names, in index order —
 * DERIVED from RETENTION_CONFLICT rather than restated, so the identity the
 * materialization check expects can never drift from the identity the database
 * enforces. Restating it is how the two silently disagreed before.
 */
const CONFLICT_IDENTITY = Object.freeze(RETENTION_CONFLICT.split(','));

const IDENTITY_SEP = '\u001f';
const IDENTITY_NULL = '\u0000NULL';

/**
 * The database identity of one row. `line` is an unconstrained `numeric`, so it
 * is normalised through Number() — otherwise 0.5 on the way in and "0.50" on
 * the way out would read as two identities for one stored row.
 *
 * Every key column is NOT NULL in production (measured: 0 nulls across 328,262
 * rows), so PostgreSQL's NULLS DISTINCT behaviour never applies. A null still
 * gets its own marker rather than collapsing to '' — an empty string is a real
 * value and must not be confused with an absent one.
 */
function rowIdentity(row) {
  return CONFLICT_IDENTITY.map((c) => {
    const v = row ? row[c] : undefined;
    if (v === null || v === undefined) return IDENTITY_NULL;
    return c === 'line' ? String(Number(v)) : String(v);
  }).join(IDENTITY_SEP);
}

function identityDigest(identities) {
  return crypto.createHash('sha256').update([...identities].sort().join('\n')).digest('hex').slice(0, 32);
}

/**
 * What SHOULD materialize, derived from the FINAL outbound payload using the
 * exact database identity — never from `attempted`, which counts rows sent, not
 * identities that can exist.
 */
function expectedMaterialization(rows) {
  const list = Array.isArray(rows) ? rows : [];
  const seen = new Set();
  let collisions = 0;
  for (const r of list) {
    const id = rowIdentity(r);
    if (seen.has(id)) collisions += 1;
    else seen.add(id);
  }
  return {
    outbound_rows: list.length,
    expected_identities: seen.size,
    collision_count: collisions,
    digest: identityDigest(seen),
    identities: seen,
  };
}

const MATERIALIZATION = Object.freeze({
  COMPLETE: 'MATERIALIZATION_COMPLETE',
  MISSING: 'MATERIALIZATION_MISSING',
  EXTRA: 'MATERIALIZATION_EXTRA',
  COLLISION: 'MATERIALIZATION_UNEXPECTED_COLLISION',
  TRANSPORT_FAILED: 'MATERIALIZATION_UNPROVEN_TRANSPORT_FAILED',
  NOT_RECONCILED: 'MATERIALIZATION_NOT_RECONCILED',
});

/**
 * Exact SET comparison, not a count comparison. Two sets of equal size can
 * still differ, and a cohort that swapped one identity for another would pass
 * every count test ever written.
 *
 * A cohort qualifies ONLY when transport completed, the sets are equal, AND the
 * outbound payload held no colliding identity — a collision passes set equality
 * by construction (the discarded row was never in the expected set) while real
 * rows were lost.
 */
function reconcileMaterialization({ expected, actualIdentities, transportStatus }) {
  if (!expected || typeof expected.expected_identities !== 'number') {
    throw new TypeError('reconcileMaterialization requires an expectedMaterialization() result');
  }
  const actual = actualIdentities instanceof Set ? actualIdentities : new Set(actualIdentities || []);
  const exp = expected.identities instanceof Set ? expected.identities : new Set();
  const missing = [...exp].filter((i) => !actual.has(i));
  const extra = [...actual].filter((i) => !exp.has(i));
  const out = {
    expected_materialized_count: expected.expected_identities,
    actual_materialized_count: actual.size,
    outbound_rows: expected.outbound_rows,
    missing_identity_count: missing.length,
    extra_identity_count: extra.length,
    collision_count: expected.collision_count,
    status: MATERIALIZATION.NOT_RECONCILED,
  };
  if (transportStatus && transportStatus !== TERMINAL.COMPLETE) {
    out.status = MATERIALIZATION.TRANSPORT_FAILED;
    return out;
  }
  if (missing.length) out.status = MATERIALIZATION.MISSING;
  else if (extra.length) out.status = MATERIALIZATION.EXTRA;
  else if (expected.collision_count > 0) out.status = MATERIALIZATION.COLLISION;
  else out.status = MATERIALIZATION.COMPLETE;
  return out;
}

/* ------------------------------------------------------------------ *
 * TERMINAL RETENTION STATE
 *
 * `persist()` writes in CHUNKS and STOPS ON THE FIRST FAILED CHUNK. Chunks
 * committed before the failure are already durable, so a failed cycle can
 * leave real, valid-looking rows behind. Row presence under a snapshot_id is
 * therefore NOT completion evidence, and neither is a uniform captured_at.
 *
 * The invariant: written < attempted with attempted > 0 is a FAILED cycle.
 * A partial cycle is never degraded success.
 *
 * `written` counts rows in successfully COMMITTED CHUNKS — not rows inserted.
 * The upsert uses ignoreDuplicates, so a re-run legitimately inserts far fewer
 * database rows than it writes. Comparing `written` to count(*) for a
 * snapshot_id will disagree by design; that is not a partial write.
 * ------------------------------------------------------------------ */

const TERMINAL = Object.freeze({
  /** attempted === 0 — a refusal-only slate is still a legitimate cycle. */
  NOTHING_TO_PERSIST: 'NOTHING_TO_PERSIST',
  /** No database configured (dev/test). Not a failure. */
  SKIPPED_NO_DATABASE: 'SKIPPED_NO_DATABASE',
  /** attempted > 0, written === attempted, no unresolved error. */
  COMPLETE: 'COMPLETE',
  /** attempted > 0, written === 0 — the first chunk failed. */
  FAILED_ZERO_WRITE: 'FAILED_ZERO_WRITE',
  /** attempted > 0, 0 < written < attempted — a later chunk failed. */
  FAILED_PARTIAL: 'FAILED_PARTIAL',
  /**
   * Counts look complete but an error is unresolved. Unreachable through
   * today's loop (it breaks before crediting a failed chunk), and kept
   * because the alternative is reporting COMPLETE with an error in hand.
   */
  FAILED_UNRESOLVED_ERROR: 'FAILED_UNRESOLVED_ERROR',
});

const FAILURE_STATUSES = Object.freeze([
  TERMINAL.FAILED_ZERO_WRITE, TERMINAL.FAILED_PARTIAL, TERMINAL.FAILED_UNRESOLVED_ERROR,
]);

function isRetentionFailure(status) { return FAILURE_STATUSES.includes(status); }

/**
 * Classify the EXACT object `persist()` returned. It never recomputes
 * attempted or written — a second calculation could disagree with the writer,
 * and then the status would describe something that did not happen.
 */
function classifyPersist(result) {
  if (!result || typeof result.attempted !== 'number' || typeof result.written !== 'number') {
    throw new TypeError('classifyPersist requires the exact persist() result');
  }
  const { attempted, written, skipped, error } = result;
  if (attempted === 0) return TERMINAL.NOTHING_TO_PERSIST;
  if (skipped) return TERMINAL.SKIPPED_NO_DATABASE;
  if (written === 0) return TERMINAL.FAILED_ZERO_WRITE;
  if (written < attempted) return TERMINAL.FAILED_PARTIAL;
  // written >= attempted from here.
  if (error) return TERMINAL.FAILED_UNRESOLVED_ERROR;
  return written === attempted ? TERMINAL.COMPLETE : TERMINAL.FAILED_UNRESOLVED_ERROR;
}

/**
 * Latest terminal retention result per sport, for the internal status probe.
 * In-memory and per-process on purpose: this is an observability surface, not
 * a record. The record is model_snapshots.
 */
const lastTerminal = new Map();

function recordTerminal({ sport, snapshotId, result, completedAt, rows }) {
  const status = classifyPersist(result);
  // Derived from the FINAL outbound payload, which does not survive the call.
  // This is the one materialization fact unrecoverable from the database
  // afterwards, which is why it is the only one recorded at runtime.
  const expected = rows ? expectedMaterialization(rows) : null;
  const entry = Object.freeze({
    sport: sport || null,
    snapshot_id: snapshotId || null,
    attempted: result.attempted,
    written: result.written,
    status,
    completed_at: completedAt || new Date().toISOString(),
    code_sha: codeSha(),
    // Message only — never row payloads.
    error_summary: result.error ? String(result.error).slice(0, 300) : null,
    // Counts and a digest only — never the identities, which carry player names.
    outbound_rows: expected ? expected.outbound_rows : null,
    expected_materialized_count: expected ? expected.expected_identities : null,
    outbound_collision_count: expected ? expected.collision_count : null,
    expected_identity_digest: expected ? expected.digest : null,
  });
  if (sport) lastTerminal.set(sport, entry);
  return entry;
}

function lastRetention() {
  const out = {};
  for (const [sport, entry] of lastTerminal) out[sport] = entry;
  return out;
}

function resetTerminal() { lastTerminal.clear(); }

module.exports = {
  MODEL_VERSION,
  TERMINAL,
  RETENTION_CONFLICT,
  LEGACY_CONFLICT,
  LEGACY_CONFLICT_INDEX,
  isLegacyConflictBlock,
  upsertSnapshotChunk,
  MATERIALIZATION,
  CONFLICT_IDENTITY,
  rowIdentity,
  identityDigest,
  expectedMaterialization,
  reconcileMaterialization,
  classifyPersist,
  isRetentionFailure,
  recordTerminal,
  lastRetention,
  resetTerminal,
  REPAIRED_CHAMPION_VERSION,
  codeSha,
  rowsFromSides,
  createCollector,
  mergeEnrichment,
  mergeChainShadow,
  mergeProbabilityContract,
  persist,
  attachLineage,
  commitPublication,
  isValidLineageAction,
  VALID_LINEAGE_ACTION_FIELDS,
  familyScopesFrom,
  recoverFromFork,
  isSupersedesConflict,
  FORK_RETRY_LIMIT,
  LINEAGE_KEYS,
  LINEAGE_FETCH_CLAIM,
  newSnapshotId,
  __internals: { numOrNull, intOrNull, boolOrNull },
};