// lib/review/coordinator-contract.mjs
// SKAL-1·4a — deterministic reference implementation of the review-coordinator
// 4-pass contract (agents/review-coordinator.md §"Your 4-pass process").
//
// This is a DETERMINISTIC SUBSET, not a full mirror of the LLM coordinator.
// It implements the pure, hermetic passes and DELIBERATELY EXCLUDES the parts
// that need a live filesystem or LLM judgement (which belong to the 4c
// LLM-in-the-loop eval, not this all-agree foundation tier):
//   - Pass 2 "Accuracy" file-existence / line-plausibility glob (fs I/O).
//   - Pass 2 "Actionability" imperative-verb heuristic — the real coordinator
//     uses LLM judgement here; a verb-list approximation would DIVERGE from the
//     contract being mirrored, so only the deterministic "recommended_action is
//     present-and-non-empty when supplied" half is kept.
//   - The doc's 4-tuple `(file,line,rule_key,title)` id recompute — the shipped
//     `computeFindingId` is 3-arg `(file,line,rule_key)`; this module follows
//     the shipped code and flags the doc divergence (the 4-tuple id is not
//     producible by the current helper).
//
// What IS implemented, purely: Pass 1 (triplet dedup → highest-severity-wins
// survivor + conformance tiebreak + detail concat + raised_by provenance),
// Pass 2 succinctness + actionability-presence, Pass 3 reasonableness
// (citation / unknown-rule_key suppression, severity-mismatch correction),
// Pass 4 verdict thresholds — fail-closed: a suppression that did not REFUTE
// the finding, and a reviewer that never reported, forbid ALLOW (see
// classifySuppression). No LLM, no network, no time, no randomness.
//
// Reuses: SEVERITY_VALUES / RULE_KEYS / getRule (rule-catalogue.mjs),
// computeFindingId (finding-id.mjs, triplet), validateFindings
// (findings-schema.mjs). Triplet key format mirrors
// scripts/bakeoff-armA-merge.mjs:33; raised_by provenance mirrors
// lib/review/plan-review-dedup.mjs.

import { SEVERITY_VALUES, RULE_KEYS, getRule } from './rule-catalogue.mjs';
import { computeFindingId } from '../parsers/finding-id.mjs';
import { validateFindings } from './findings-schema.mjs';

export const JUDGE_TITLE_MAX = 100;
export const JUDGE_DETAIL_MAX = 800;

// ---- Suppression classification (fail-closed) --------------------------------
//
// A removal is `dropped` ONLY when the test refuted the finding as a claim
// about this codebase. Every other removal is `unverified`: the coordinator
// took the finding out of the count without ever establishing it was unreal,
// so it may not be spent as evidence of a clean review.

/**
 * Reasons that REFUTE. `no-citation` is the only one this deterministic subset
 * can emit: a finding whose `file` is empty or whose `line` is negative names
 * no location, so it makes no checkable claim at all
 * (agents/review-coordinator.md Pass 3 — "Speculative 'code might break
 * somewhere' findings have no anchor").
 *
 * `accuracy:refuted` (Pass 2 Accuracy — a citation escaping the repo root) and
 * `file-existence:refuted` (Pass 3 — absent from both working tree and diff)
 * are emitted by the LLM coordinator, whose fs/judgement branches this module
 * excludes. They are declared here anyway: the vocabulary is owned in one
 * place so prose and lib cannot drift.
 */
export const REFUTING_REASONS = Object.freeze(new Set([
  'no-citation',
  'accuracy:refuted',
  'file-existence:refuted',
]));

/**
 * The reason vocabulary on the unverified side. `file-existence:indeterminate`
 * is emitted by the LLM coordinator's Pass 3 (which runs the fs Glob this
 * module deliberately excludes); the vocabulary is owned here so prose and lib
 * cannot drift.
 */
export const UNVERIFIED_REASONS = Object.freeze([
  'succinctness:title',
  'succinctness:detail',
  'actionability:empty',
  'unknown-rule_key',
  'file-existence:indeterminate',
]);

/**
 * Classify a suppression reason. Anything not declared refuting is
 * `unverified` — the default is fail-CLOSED, so a reason introduced later
 * without a decision cannot silently move the verdict toward ALLOW.
 * @param {string} reason
 * @returns {'refuted'|'unverified'}
 */
export function classifySuppression(reason) {
  return REFUTING_REASONS.has(reason) ? 'refuted' : 'unverified';
}

/**
 * Tag a finding with its suppression reason and route it to the refuted
 * (`dropped`) or the `unverified` bucket.
 * @param {object} finding
 * @param {string} reason
 * @param {object[]} dropped
 * @param {object[]} unverified
 */
function suppress(finding, reason, dropped, unverified) {
  const tagged = { ...finding, suppressed_reason: reason };
  if (classifySuppression(reason) === 'refuted') dropped.push(tagged);
  else unverified.push(tagged);
}

/**
 * Catalogue-tier rank of a severity: lower number = higher severity.
 * BLOCKER=0 … SUGGESTION=3; an unknown severity ranks last.
 * @param {string} severity
 * @returns {number}
 */
export function severityRank(severity) {
  const i = SEVERITY_VALUES.indexOf(severity);
  return i === -1 ? SEVERITY_VALUES.length : i;
}

function isConformance(reviewer) {
  return typeof reviewer === 'string' && reviewer.toLowerCase().includes('conformance');
}

function tripletKey(f) {
  return `${f.file} ${f.line} ${f.rule_key}`;
}

/**
 * Validate each reviewer payload and collect findings from the VALID ones,
 * tagging each finding with its source reviewer (mirrors mergeArmA — invalid
 * payloads are skipped, not crashed-on).
 * @param {Array<{reviewer?: string, findings: object[]}>} reviewerPayloads
 * @returns {{ findings: object[], skipped: Array<{reviewer: string|null, error_codes: string[]}> }}
 */
export function ingest(reviewerPayloads) {
  const findings = [];
  const skipped = [];
  for (const payload of reviewerPayloads) {
    const r = validateFindings(payload);
    if (!r.valid) {
      skipped.push({ reviewer: payload?.reviewer ?? null, error_codes: r.errors.map((e) => e.code) });
      continue;
    }
    for (const f of payload.findings) {
      findings.push({ ...f, reviewer: f.reviewer ?? payload.reviewer ?? f.owner_reviewer ?? null });
    }
  }
  return { findings, skipped };
}

/**
 * Pass 1 — dedup by (file, line, rule_key) triplet. Survivor = highest
 * catalogue severity; severity tie → prefer the conformance reviewer; carries
 * raised_by provenance, concatenates other reviewers' attribution into detail,
 * and recomputes the id over the triplet.
 * @param {object[]} findings
 * @returns {object[]}
 */
export function dedupByTriplet(findings) {
  const groups = new Map();
  for (const f of findings) {
    const key = tripletKey(f);
    if (!groups.has(key)) groups.set(key, []);
    groups.get(key).push(f);
  }
  const out = [];
  for (const group of groups.values()) {
    let survivor = group[0];
    for (const f of group.slice(1)) {
      const higher = severityRank(f.severity) < severityRank(survivor.severity);
      const tieToConformance =
        severityRank(f.severity) === severityRank(survivor.severity) &&
        isConformance(f.reviewer) && !isConformance(survivor.reviewer);
      if (higher || tieToConformance) survivor = f;
    }
    const raised_by = [...new Set(group.map((f) => f.reviewer).filter(Boolean))];
    const others = group.filter((f) => f !== survivor);
    let detail = survivor.detail;
    if (others.length > 0) {
      detail = survivor.detail ?? '';
      for (const o of others) {
        detail += `\nAlso flagged by ${o.reviewer ?? 'unknown'}: ${o.title ?? o.rule_key}.`;
      }
    }
    const id = computeFindingId(survivor.file, survivor.line, survivor.rule_key);
    out.push({ ...survivor, id, ...(detail !== undefined ? { detail } : {}), raised_by });
  }
  return out;
}

/**
 * Pass 2 — HubSpot Judge (deterministic subset): drop on succinctness
 * (title > 100 or detail > 800 chars) and actionability (recommended_action,
 * when present, must be a non-empty string). The imperative-verb test is
 * excluded (LLM judgement).
 *
 * Both tests read a `.length`; neither examines the claim, so neither can
 * establish the finding is unreal. Both therefore route to `unverified`.
 * `dropped` stays in the signature for the refuting Pass-2 filter this subset
 * excludes (Accuracy: a path-traversal escape IS a refutation).
 * @param {object[]} findings
 * @returns {{ kept: object[], dropped: object[], unverified: object[] }}
 */
export function judgeFilter(findings) {
  const kept = [];
  const dropped = [];
  const unverified = [];
  for (const f of findings) {
    const titleLen = (f.title ?? '').length;
    const detailLen = (f.detail ?? '').length;
    let reason = null;
    if (titleLen > JUDGE_TITLE_MAX) reason = 'succinctness:title';
    else if (detailLen > JUDGE_DETAIL_MAX) reason = 'succinctness:detail';
    else if ('recommended_action' in f &&
      (typeof f.recommended_action !== 'string' || f.recommended_action.trim().length === 0)) {
      reason = 'actionability:empty';
    }
    if (reason) suppress(f, reason, dropped, unverified);
    else kept.push(f);
  }
  return { kept, dropped, unverified };
}

/**
 * Pass 3 — Cloudflare reasonableness (deterministic subset): drop findings
 * with no citation (empty file / line < 0) or an unknown rule_key; CORRECT a
 * severity that does not match the catalogue tier (a correction, not a drop).
 * The fs file-existence glob is excluded (I/O) — its indeterminate branch is
 * prose-side, tokenised as `file-existence:indeterminate`.
 *
 * `no-citation` REFUTES (the finding names no location, so it makes no
 * checkable claim) and is dropped. `unknown-rule_key` does not: an ad-hoc key
 * is a real defect wearing the wrong label — v5.1.1 high-effort mode already
 * KEEPS these, normalised to PLAN_EXECUTE_DRIFT — so it routes to `unverified`.
 * @param {object[]} findings
 * @returns {{ kept: object[], dropped: object[], unverified: object[] }}
 */
export function reasonablenessFilter(findings) {
  const kept = [];
  const dropped = [];
  const unverified = [];
  for (const f of findings) {
    if (typeof f.file !== 'string' || f.file.length === 0 ||
      (typeof f.line === 'number' && f.line < 0)) {
      suppress(f, 'no-citation', dropped, unverified);
      continue;
    }
    if (!RULE_KEYS.has(f.rule_key)) {
      suppress(f, 'unknown-rule_key', dropped, unverified);
      continue;
    }
    const rule = getRule(f.rule_key);
    if (rule && f.severity !== rule.severity) {
      kept.push({ ...f, severity: rule.severity, original_severity: f.severity });
    } else {
      kept.push(f);
    }
  }
  return { kept, dropped, unverified };
}

/**
 * Pass 4 — compute the verdict from severity counts (after dedup + filtering).
 * BLOCKER ≥ 1 → BLOCK; else MAJOR ≥ 1 → WARN; else ALLOW.
 *
 * FAIL-CLOSED: ALLOW additionally requires that nothing is `unverified` and
 * that every expected reviewer reported. Neither ever RAISES a verdict — the
 * severity thresholds are untouched — they only forbid the clean one, so the
 * worst case of a false unverified is WARN plus a stated reason, never a
 * silent pass. Unverified findings are NOT counted into a severity tier: their
 * severity is reviewer-asserted and was never substantiated.
 *
 * @param {object[]} findings
 * @param {{ unverified?: object[], missingReviewers?: string[] }} [options]
 * @returns {{ verdict: 'BLOCK'|'WARN'|'ALLOW', counts: Record<string, number>, allow_blocked_by: string[] }}
 */
export function computeVerdict(findings, options = {}) {
  const counts = { BLOCKER: 0, MAJOR: 0, MINOR: 0, SUGGESTION: 0 };
  for (const f of findings) {
    if (counts[f.severity] !== undefined) counts[f.severity] += 1;
  }

  const unverified = options.unverified ?? [];
  const missingReviewers = options.missingReviewers ?? [];
  const allow_blocked_by = [];
  const byReason = new Map();
  for (const f of unverified) {
    const reason = f?.suppressed_reason ?? 'unspecified';
    byReason.set(reason, (byReason.get(reason) ?? 0) + 1);
  }
  for (const [reason, n] of byReason) allow_blocked_by.push(`unverified:${reason} (${n})`);
  for (const r of missingReviewers) allow_blocked_by.push(`missing-reviewer:${r}`);

  let verdict;
  if (counts.BLOCKER >= 1) verdict = 'BLOCK';
  else if (counts.MAJOR >= 1) verdict = 'WARN';
  else if (allow_blocked_by.length > 0) verdict = 'WARN';
  else verdict = 'ALLOW';
  return { verdict, counts, allow_blocked_by };
}

/**
 * Run the full deterministic contract: ingest → Pass 1 → Pass 2 → Pass 3 → Pass 4.
 *
 * `options.expectedReviewers` names the reviewers this review was supposed to
 * hear from. A reviewer that is absent from the payloads, or whose payload
 * failed schema validation and was thrown away at ingest, lands in
 * `missing_reviewers` and forbids ALLOW: an unread reviewer is an absent one,
 * and zero findings from a silent reviewer must not read like zero findings
 * from a clean diff.
 *
 * `suppressed` stays the UNION of `dropped` (refuted) and `unverified` so
 * existing consumers keep their meaning; `unverified` is the subset that
 * forbids ALLOW. Do not iterate both and count twice.
 *
 * @param {Array<{reviewer?: string, findings: object[]}>} reviewerPayloads
 * @param {{ expectedReviewers?: string[] }} [options]
 * @returns {{ verdict: string, counts: Record<string, number>, findings: object[], suppressed: object[], unverified: object[], skipped: object[], missing_reviewers: string[], allow_blocked_by: string[] }}
 */
export function runContract(reviewerPayloads, options = {}) {
  const { findings: ingested, skipped } = ingest(reviewerPayloads);
  const deduped = dedupByTriplet(ingested);
  const judged = judgeFilter(deduped);
  const reasoned = reasonablenessFilter(judged.kept);
  const unverified = [...judged.unverified, ...reasoned.unverified];

  const reported = new Set();
  for (const payload of reviewerPayloads) {
    if (typeof payload?.reviewer === 'string' && payload.reviewer.length > 0) reported.add(payload.reviewer);
  }
  for (const s of skipped) reported.delete(s.reviewer);
  const missing_reviewers = [];
  for (const s of skipped) {
    const name = s.reviewer ?? 'unnamed reviewer';
    if (!missing_reviewers.includes(name)) missing_reviewers.push(name);
  }
  for (const r of options.expectedReviewers ?? []) {
    if (!reported.has(r) && !missing_reviewers.includes(r)) missing_reviewers.push(r);
  }

  const { verdict, counts, allow_blocked_by } = computeVerdict(reasoned.kept, {
    unverified,
    missingReviewers: missing_reviewers,
  });
  return {
    verdict,
    counts,
    findings: reasoned.kept,
    suppressed: [...judged.dropped, ...judged.unverified, ...reasoned.dropped, ...reasoned.unverified],
    unverified,
    skipped,
    missing_reviewers,
    allow_blocked_by,
  };
}

// ---- CLI shim ----------------------------------------------------------------

if (import.meta.url === `file://${process.argv[1]}`) {
  const args = process.argv.slice(2);
  const filePath = args.find((a) => !a.startsWith('--'));
  if (!filePath) {
    process.stderr.write('Usage: coordinator-contract.mjs [--json] <reviewer-payloads.json>\n');
    process.exit(2);
  }
  const { readFileSync } = await import('node:fs');
  const payloads = JSON.parse(readFileSync(filePath, 'utf-8'));
  const result = runContract(Array.isArray(payloads) ? payloads : [payloads]);
  if (args.includes('--json')) {
    process.stdout.write(JSON.stringify(result, null, 2) + '\n');
  } else {
    process.stdout.write(`coordinator-contract: ${result.verdict} (${result.findings.length} findings, ${result.suppressed.length} suppressed)\n`);
  }
  process.exit(0);
}