// check_evidence_health.ts — high-level audit of the materialized
// EvidenceRecord substrate. Answers two questions Phase 3 needs:
//
//   1. PROVENANCE ROUND-TRIP — sample N output rows, look up the
//      source row at the recorded (source_file, line_offset),
//      recompute canonicalSha256, confirm it matches provenance.sig_hash.
//      Hard pass/fail. If even one row fails, provenance is theater.
//
//   2. SCORE-READINESS COVERAGE — for each source, what fraction of
//      materialized rows carry the signals the Success Scorer will
//      need: model_role, success_markers, failure_markers,
//      observer_verdict, latency_ms, retrieved_context, text. Tells
//      Phase 3 which sources to read from for each gate.
//
// Output: markdown report to stdout + data/_kb/evidence_health.md.
//
// Run: bun run scripts/distillation/check_evidence_health.ts

import { existsSync, readFileSync, readdirSync, statSync, writeFileSync } from "node:fs";
import { resolve } from "node:path";
import { canonicalSha256 } from "../../auditor/schemas/distillation/types";

const ROOT = process.env.LH_DISTILL_ROOT ?? "/home/profit/lakehouse";
const SAMPLE_FOR_PROVENANCE = 30;

interface CoverageBucket {
  source: string;
  total: number;
  with_model_role: number;
  with_model_name: number;
  with_success_markers: number;
  with_failure_markers: number;
  with_observer_verdict: number;
  with_latency_ms: number;
  with_retrieved_context: number;
  with_text: number;
  scoreable: number;            // has at least ONE signal the scorer can use
}

interface ProvenanceCheck {
  passed: number;
  failed: number;
  failures: Array<{ output_path: string; line: number; reason: string }>;
}

function listEvidenceFiles(evidence_root: string): string[] {
  const out: string[] = [];
  if (!existsSync(evidence_root)) return out;
  for (const yyyy of readdirSync(evidence_root).sort()) {
    const ydir = resolve(evidence_root, yyyy);
    if (!statSync(ydir).isDirectory()) continue;
    for (const mm of readdirSync(ydir).sort()) {
      const mdir = resolve(ydir, mm);
      if (!statSync(mdir).isDirectory()) continue;
      for (const dd of readdirSync(mdir).sort()) {
        const ddir = resolve(mdir, dd);
        if (!statSync(ddir).isDirectory()) continue;
        for (const f of readdirSync(ddir)) {
          if (f.endsWith(".jsonl")) out.push(resolve(ddir, f));
        }
      }
    }
  }
  return out;
}

// Has at least one deterministic signal the Phase 3 scorer can act on.
// Order is generous: any of these counts as "scoreable", because the
// scorer combines multiple signals.
function isScoreable(row: any): boolean {
  if (Array.isArray(row.success_markers) && row.success_markers.length > 0) return true;
  if (Array.isArray(row.failure_markers) && row.failure_markers.length > 0) return true;
  if (typeof row.observer_verdict === "string") return true;
  if (row.validation_results && Object.keys(row.validation_results).length > 0) return true;
  if (Array.isArray(row.observer_notes) && row.observer_notes.length > 0) return true;
  return false;
}

function bucketStart(source: string): CoverageBucket {
  return {
    source, total: 0,
    with_model_role: 0, with_model_name: 0,
    with_success_markers: 0, with_failure_markers: 0,
    with_observer_verdict: 0, with_latency_ms: 0,
    with_retrieved_context: 0, with_text: 0,
    scoreable: 0,
  };
}

function pct(n: number, total: number): string {
  if (total === 0) return "—";
  return Math.round(100 * n / total) + "%";
}

async function main() {
  const evidenceFiles = listEvidenceFiles(resolve(ROOT, "data/evidence"));
  if (evidenceFiles.length === 0) {
    console.error("No evidence files found. Run scripts/distillation/build_evidence_index.ts first.");
    process.exit(1);
  }

  // ── 1. Coverage scan ────────────────────────────────────────────
  const buckets = new Map<string, CoverageBucket>();
  const allOutputRows: Array<{ output_path: string; line: number; row: any }> = [];

  for (const evPath of evidenceFiles) {
    const sourceLabel = evPath.split("/").pop()!.replace(/\.jsonl$/, "");
    const b = buckets.get(sourceLabel) ?? bucketStart(sourceLabel);
    const lines = readFileSync(evPath, "utf8").split("\n").filter(Boolean);
    for (let i = 0; i < lines.length; i++) {
      const row = JSON.parse(lines[i]);
      b.total++;
      if (row.model_role) b.with_model_role++;
      if (row.model_name) b.with_model_name++;
      if (Array.isArray(row.success_markers) && row.success_markers.length > 0) b.with_success_markers++;
      if (Array.isArray(row.failure_markers) && row.failure_markers.length > 0) b.with_failure_markers++;
      if (typeof row.observer_verdict === "string") b.with_observer_verdict++;
      if (typeof row.latency_ms === "number") b.with_latency_ms++;
      if (row.retrieved_context && Object.keys(row.retrieved_context).length > 0) b.with_retrieved_context++;
      if (typeof row.text === "string" && row.text.length > 0) b.with_text++;
      if (isScoreable(row)) b.scoreable++;
      allOutputRows.push({ output_path: evPath, line: i, row });
    }
    buckets.set(sourceLabel, b);
  }

  // ── 2. Provenance round-trip on a random sample ─────────────────
  const sampleSize = Math.min(SAMPLE_FOR_PROVENANCE, allOutputRows.length);
  const indices = new Set<number>();
  // Deterministic-ish sample: stride through evenly so we hit different sources.
  const stride = Math.max(1, Math.floor(allOutputRows.length / sampleSize));
  for (let i = 0; i < allOutputRows.length && indices.size < sampleSize; i += stride) indices.add(i);
  // Top up with the tail in case stride truncates early.
  while (indices.size < sampleSize) indices.add(allOutputRows.length - 1 - indices.size);

  const provCheck: ProvenanceCheck = { passed: 0, failed: 0, failures: [] };
  // Cache source-file lines so we don't re-read big files repeatedly.
  const sourceCache = new Map<string, string[]>();

  for (const idx of indices) {
    const { output_path, line, row } = allOutputRows[idx];
    const prov = row.provenance;
    if (!prov || !prov.source_file || prov.line_offset == null || !prov.sig_hash) {
      provCheck.failed++;
      provCheck.failures.push({ output_path, line, reason: "missing provenance fields" });
      continue;
    }
    const sourceAbs = resolve(ROOT, prov.source_file);
    if (!sourceCache.has(sourceAbs)) {
      if (!existsSync(sourceAbs)) {
        provCheck.failed++;
        provCheck.failures.push({ output_path, line, reason: `source missing: ${prov.source_file}` });
        continue;
      }
      sourceCache.set(sourceAbs, readFileSync(sourceAbs, "utf8").split("\n"));
    }
    const sourceLines = sourceCache.get(sourceAbs)!;
    if (prov.line_offset >= sourceLines.length) {
      provCheck.failed++;
      provCheck.failures.push({ output_path, line, reason: `line_offset ${prov.line_offset} past EOF (source has ${sourceLines.length} lines)` });
      continue;
    }
    const sourceLine = sourceLines[prov.line_offset];
    let sourceRow: any;
    try { sourceRow = JSON.parse(sourceLine); }
    catch (e) {
      provCheck.failed++;
      provCheck.failures.push({ output_path, line, reason: `source line not JSON: ${(e as Error).message.slice(0, 60)}` });
      continue;
    }
    const recomputed = await canonicalSha256(sourceRow);
    if (recomputed !== prov.sig_hash) {
      provCheck.failed++;
      provCheck.failures.push({
        output_path, line,
        reason: `sig_hash mismatch: prov=${prov.sig_hash.slice(0, 16)}… recomputed=${recomputed.slice(0, 16)}…`,
      });
      continue;
    }
    provCheck.passed++;
  }

  // ── 3. Render markdown ──────────────────────────────────────────
  const md: string[] = [];
  md.push("# Evidence Health — Phase 2 high-level audit");
  md.push("");
  md.push(`**Run:** ${new Date().toISOString()}`);
  md.push(`**Evidence files:** ${evidenceFiles.length}`);
  md.push(`**Total records:** ${allOutputRows.length}`);
  md.push("");
  md.push("## 1. Provenance round-trip");
  md.push("");
  md.push(`Sample size: **${sampleSize}** rows (stride sample across all evidence).`);
  md.push("");
  md.push(`| Passed | Failed |`);
  md.push(`|---|---|`);
  md.push(`| ${provCheck.passed} | ${provCheck.failed} |`);
  md.push("");
  if (provCheck.failed > 0) {
    md.push("### Failures");
    for (const f of provCheck.failures.slice(0, 20)) {
      md.push(`- \`${f.output_path.split("/").slice(-2).join("/")}\` line ${f.line}: ${f.reason}`);
    }
  } else {
    md.push("**All sampled rows traced cleanly back to source rows with matching canonical sig_hash.**");
  }
  md.push("");
  md.push("## 2. Score-readiness coverage");
  md.push("");
  md.push("Per source, fraction of materialized rows carrying each signal the Phase 3 Success Scorer will read.");
  md.push("");
  md.push("| Source | Rows | role | name | success | failure | obs.verdict | latency | retrieval | text | scoreable |");
  md.push("|---|---|---|---|---|---|---|---|---|---|---|");
  const sortedBuckets = Array.from(buckets.values()).sort((a, b) => b.total - a.total);
  for (const b of sortedBuckets) {
    md.push(`| ${b.source} | ${b.total} | ${pct(b.with_model_role, b.total)} | ${pct(b.with_model_name, b.total)} | ${pct(b.with_success_markers, b.total)} | ${pct(b.with_failure_markers, b.total)} | ${pct(b.with_observer_verdict, b.total)} | ${pct(b.with_latency_ms, b.total)} | ${pct(b.with_retrieved_context, b.total)} | ${pct(b.with_text, b.total)} | **${pct(b.scoreable, b.total)}** |`);
  }
  md.push("");
  // Aggregate totals row
  const totals = sortedBuckets.reduce((acc, b) => ({
    total: acc.total + b.total,
    role: acc.role + b.with_model_role,
    name: acc.name + b.with_model_name,
    success: acc.success + b.with_success_markers,
    failure: acc.failure + b.with_failure_markers,
    obs: acc.obs + b.with_observer_verdict,
    lat: acc.lat + b.with_latency_ms,
    ret: acc.ret + b.with_retrieved_context,
    text: acc.text + b.with_text,
    score: acc.score + b.scoreable,
  }), { total: 0, role: 0, name: 0, success: 0, failure: 0, obs: 0, lat: 0, ret: 0, text: 0, score: 0 });
  md.push(`**Aggregate:** ${totals.total} rows · role ${pct(totals.role, totals.total)} · name ${pct(totals.name, totals.total)} · success ${pct(totals.success, totals.total)} · failure ${pct(totals.failure, totals.total)} · obs.verdict ${pct(totals.obs, totals.total)} · latency ${pct(totals.lat, totals.total)} · retrieval ${pct(totals.ret, totals.total)} · text ${pct(totals.text, totals.total)} · scoreable **${pct(totals.score, totals.total)}**`);
  md.push("");
  md.push("## 3. Phase 3 readiness");
  md.push("");
  if (provCheck.failed > 0) {
    md.push("**❌ NOT READY** — provenance round-trip failed. Fix materializer or transforms before Phase 3.");
  } else if (totals.score < totals.total * 0.5) {
    md.push(`**⚠️ PARTIAL READINESS** — only ${pct(totals.score, totals.total)} of records are scoreable. Phase 3 will produce many \`needs_human_review\` until transforms enrich more sources with markers.`);
  } else {
    md.push(`**✓ READY** — provenance traces, ${pct(totals.score, totals.total)} of records carry scorer signals. Phase 3 can begin.`);
  }
  md.push("");

  const out = md.join("\n");
  console.log(out);
  writeFileSync(resolve(ROOT, "data/_kb/evidence_health.md"), out);

  if (provCheck.failed > 0) process.exit(1);
}

if (import.meta.main) {
  main().catch(e => { console.error(e); process.exit(1); });
}