// Product-scan (scan-pfm) accuracy regression tool.
//
// Hits the live /api/scan-pfm endpoint for every labeled image in
// backend/sources/product_manual_labels.json, checks 3 fields (no_sku,
// nama_item, expiry_date) against ground truth, splits results into a
// Training Set (gallery photos under foto-kemasan-v2/ that trained the
// classifier itself) vs a Validation Set (flat filenames dropped in
// backend/sources/product-test-images/), and appends a summary to
// backend/sources/product_accuracy_history.jsonl. Every run auto-diffs
// against the last history entry and flags field/image regressions or
// improvements, so a tuning change to classify_ocr_server.py shows its
// effect immediately instead of requiring manual before/after comparison.
//
// Usage:
//   node scripts/accuracy-check-scan.mts
//   node scripts/accuracy-check-scan.mts --base-url http://localhost:3000

import fs from "node:fs";
import path from "node:path";
import { fileURLToPath } from "node:url";
import { execSync } from "node:child_process";

const __filename = fileURLToPath(import.meta.url);
const __dirname = path.dirname(__filename);

const APP_ROOT = path.join(__dirname, "..", "pfm-web-app");
const SOURCES_DIR = path.join(__dirname, "..", "sources");
// Overridable for local smoke-testing against a scratch dataset without
// touching the real ground-truth/history files.
const LABELS_PATH = process.env.ACCURACY_LABELS_PATH || path.join(SOURCES_DIR, "product_manual_labels.json");
const HISTORY_PATH = process.env.ACCURACY_HISTORY_PATH || path.join(SOURCES_DIR, "product_accuracy_history.jsonl");

const FETCH_TIMEOUT_MS = 120_000;
const FIELDS = ["no_sku", "nama_item", "expiry_date"] as const;
type Field = typeof FIELDS[number];
type Split = "training" | "validation";

interface GroundTruth {
  filename: string;
  no_sku: string;
  nama_item: string;
  expiry_date: string;
}

interface ScanResponse {
  classification?: {
    top1_name: string;
    top1_confidence: number;
    method?: string;
  };
  ocr?: {
    extracted_expired_date: string;
  };
  possibleMatches?: Array<{
    no_sku: string;
    nama_item: string;
    isBestMatch: boolean;
  }>;
}

interface Check {
  field: Field;
  match: boolean;
}

interface ResultItem {
  gt: GroundTruth;
  checks: Check[];
  method?: string;
  confidence?: number;
}

interface ClassificationStats {
  methodCounts: Record<string, number>;
  avgConfidence: number;
}

interface HistoryEntry {
  timestamp: string;
  commit: string;
  imageCount: { training: number; validation: number };
  failedImages: string[];
  fields: Record<Split, Record<Field, { correct: number; total: number }>>;
  classification: Record<Split, ClassificationStats>;
  perImage: Record<string, number>;
}

function parseArgs(argv: string[]) {
  return {
    baseUrl: process.env.ACCURACY_BASE_URL || "http://localhost:3000",
  };
}

function norm(v: unknown): string {
  if (!v) return "";
  return String(v).replace(/\s+/g, " ").trim().toUpperCase();
}

function isMatch(a: unknown, b: unknown): boolean {
  return norm(a) === norm(b);
}

function getImagePath(filename: string): string {
  if (filename.includes("/")) {
    return path.join(APP_ROOT, "public", "produk-pfm", "foto-kemasan-v2", filename);
  }
  return path.join(SOURCES_DIR, "product-test-images", filename);
}

async function checkServerReachable(baseUrl: string) {
  try {
    const res = await fetch(`${baseUrl}/api/v1/health`, { signal: AbortSignal.timeout(5000) });
    if (!res.ok) throw new Error(`HTTP ${res.status}`);
  } catch (err) {
    throw new Error(`Next dev server not reachable at ${baseUrl}. Ensure it's running.`);
  }
}

async function fetchScan(baseUrl: string, base64: string): Promise<ScanResponse> {
  const controller = new AbortController();
  const timer = setTimeout(() => controller.abort(), FETCH_TIMEOUT_MS);
  try {
    const res = await fetch(`${baseUrl}/api/scan-pfm`, {
      method: "POST",
      headers: { "Content-Type": "application/json" },
      body: JSON.stringify({ image_base64: base64 }),
      signal: controller.signal
    });
    if (!res.ok) throw new Error(`HTTP ${res.status}`);
    return await res.json();
  } finally {
    clearTimeout(timer);
  }
}

function getGitCommit(): string {
  try { return execSync("git rev-parse --short HEAD", { cwd: __dirname }).toString().trim(); }
  catch { return "unknown"; }
}

function pct(c: number, t: number) { return t === 0 ? 0 : (c / t) * 100; }
function fmtPct(n: number) { return `${n.toFixed(1)}%`; }

function fmtDelta(curr: number, prev: number | undefined): string {
  if (prev === undefined) return "";
  const d = curr - prev;
  if (Math.abs(d) < 0.05) return "±0.0";
  const sign = d > 0 ? "+" : "";
  return `${sign}${d.toFixed(1)}`;
}

function loadLastHistoryEntry(): HistoryEntry | null {
  if (!fs.existsSync(HISTORY_PATH)) return null;
  const lines = fs.readFileSync(HISTORY_PATH, "utf8").trim().split("\n").filter(Boolean);
  if (lines.length === 0) return null;
  try {
    return JSON.parse(lines[lines.length - 1]);
  } catch {
    return null;
  }
}

function aggregateFields(list: ResultItem[]): Record<Field, { correct: number; total: number }> {
  const agg = {
    no_sku: { correct: 0, total: 0 },
    nama_item: { correct: 0, total: 0 },
    expiry_date: { correct: 0, total: 0 }
  } as Record<Field, { correct: number; total: number }>;
  for (const item of list) {
    for (const check of item.checks) {
      agg[check.field].total++;
      if (check.match) agg[check.field].correct++;
    }
  }
  return agg;
}

function overallFromFields(fields: Record<Field, { correct: number; total: number }> | undefined) {
  if (!fields) return undefined;
  let correct = 0, total = 0;
  for (const f of FIELDS) {
    const s = fields[f];
    if (s) { correct += s.correct; total += s.total; }
  }
  return { correct, total };
}

function aggregateClassification(list: ResultItem[]): ClassificationStats {
  const methodCounts: Record<string, number> = {};
  let confSum = 0;
  let confCount = 0;
  for (const item of list) {
    if (item.method) methodCounts[item.method] = (methodCounts[item.method] || 0) + 1;
    if (typeof item.confidence === "number") {
      confSum += item.confidence;
      confCount++;
    }
  }
  return { methodCounts, avgConfidence: confCount ? confSum / confCount : 0 };
}

function printClassificationLine(label: string, stats: ClassificationStats, prevStats: ClassificationStats | undefined) {
  const methodStr = Object.entries(stats.methodCounts).map(([m, c]) => `${m}=${c}`).join(", ") || "n/a";
  const confStr = stats.avgConfidence ? stats.avgConfidence.toFixed(3) : "n/a";
  let suffix = "";
  if (prevStats && prevStats.avgConfidence) {
    const delta = fmtDelta(stats.avgConfidence, prevStats.avgConfidence);
    suffix = delta ? ` (Δ ${delta} vs prev)` : "";
  }
  console.log(`  ${label.padEnd(11)}: ${methodStr.padEnd(28)} avg confidence ${confStr}${suffix}`);
}

function printSummary(
  trainAgg: Record<Field, { correct: number; total: number }>,
  valAgg: Record<Field, { correct: number; total: number }>,
  trainClassStats: ClassificationStats,
  valClassStats: ClassificationStats,
  perImagePct: Record<string, number>,
  prev: HistoryEntry | null,
  imageCount: { training: number; validation: number },
  failedImages: string[]
) {
  console.log("\n=== Product Scan Accuracy Summary ===");
  console.log(`Training Images: ${imageCount.training} | Validation Images: ${imageCount.validation} | Failed: ${failedImages.length}\n`);

  const fieldCol = 14, numCol = 9, deltaCol = 8;
  const header =
    "Field".padEnd(fieldCol) +
    "Training".padStart(numCol) + "Δ".padStart(deltaCol) + "  " +
    "Validation".padStart(numCol) + "Δ".padStart(deltaCol);
  console.log(header);
  console.log("-".repeat(header.length));

  const overallTrain = { correct: 0, total: 0 };
  const overallVal = { correct: 0, total: 0 };

  for (const field of FIELDS) {
    const t = trainAgg[field];
    const v = valAgg[field];
    overallTrain.correct += t.correct; overallTrain.total += t.total;
    overallVal.correct += v.correct; overallVal.total += v.total;

    const tPct = pct(t.correct, t.total);
    const vPct = pct(v.correct, v.total);
    const tPrevStat = prev?.fields?.training?.[field];
    const vPrevStat = prev?.fields?.validation?.[field];
    const tPrevPct = tPrevStat?.total ? pct(tPrevStat.correct, tPrevStat.total) : undefined;
    const vPrevPct = vPrevStat?.total ? pct(vPrevStat.correct, vPrevStat.total) : undefined;

    const tStr = t.total ? fmtPct(tPct) : "n/a";
    const vStr = v.total ? fmtPct(vPct) : "n/a";

    console.log(
      field.padEnd(fieldCol) +
      tStr.padStart(numCol) + fmtDelta(tPct, tPrevPct).padStart(deltaCol) + "  " +
      vStr.padStart(numCol) + fmtDelta(vPct, vPrevPct).padStart(deltaCol)
    );
  }
  console.log("-".repeat(header.length));

  const tOverallPct = pct(overallTrain.correct, overallTrain.total);
  const vOverallPct = pct(overallVal.correct, overallVal.total);
  const prevTrainOverall = overallFromFields(prev?.fields?.training);
  const prevValOverall = overallFromFields(prev?.fields?.validation);
  const tOverallPrevPct = prevTrainOverall?.total ? pct(prevTrainOverall.correct, prevTrainOverall.total) : undefined;
  const vOverallPrevPct = prevValOverall?.total ? pct(prevValOverall.correct, prevValOverall.total) : undefined;

  console.log(
    "OVERALL".padEnd(fieldCol) +
    fmtPct(tOverallPct).padStart(numCol) + fmtDelta(tOverallPct, tOverallPrevPct).padStart(deltaCol) + "  " +
    fmtPct(vOverallPct).padStart(numCol) + fmtDelta(vOverallPct, vOverallPrevPct).padStart(deltaCol)
  );

  if (failedImages.length) {
    console.log(`\nFailed to parse: ${failedImages.join(", ")}`);
  }

  // Informational only - DINOv2 "confidence" is a raw cosine similarity, not a
  // calibrated probability (see docs/scan-product.md), so a delta here doesn't
  // by itself mean better/worse. Only the fields above drive regression flags.
  console.log("\nClassification (informational, not scored as pass/fail):");
  printClassificationLine("Training", trainClassStats, prev?.classification?.training);
  printClassificationLine("Validation", valClassStats, prev?.classification?.validation);

  if (prev) {
    const fieldRegressions: string[] = [];
    const fieldImprovements: string[] = [];
    for (const split of ["training", "validation"] as Split[]) {
      const agg = split === "training" ? trainAgg : valAgg;
      for (const field of FIELDS) {
        const stat = agg[field];
        if (!stat.total) continue;
        const currPct = pct(stat.correct, stat.total);
        const prevStat = prev.fields?.[split]?.[field];
        if (!prevStat?.total) continue;
        const prevPct = pct(prevStat.correct, prevStat.total);
        const d = currPct - prevPct;
        const label = `${field} (${split})`;
        if (d <= -0.05) fieldRegressions.push(`${label} ${fmtDelta(currPct, prevPct)}`);
        else if (d >= 0.05) fieldImprovements.push(`${label} ${fmtDelta(currPct, prevPct)}`);
      }
    }
    if (fieldRegressions.length) console.log(`\nField regressions: ${fieldRegressions.join(", ")}`);
    if (fieldImprovements.length) console.log(`Field improvements: ${fieldImprovements.join(", ")}`);

    const imageRegressions: string[] = [];
    const imageImprovements: string[] = [];
    for (const [filename, currPct] of Object.entries(perImagePct)) {
      const prevPct = prev.perImage?.[filename];
      if (prevPct === undefined) continue;
      const d = currPct - prevPct;
      if (d <= -0.5) imageRegressions.push(`${filename} ${fmtDelta(currPct, prevPct)}`);
      else if (d >= 0.5) imageImprovements.push(`${filename} ${fmtDelta(currPct, prevPct)}`);
    }
    if (imageRegressions.length) console.log(`\nImage regressions: ${imageRegressions.join(", ")}`);
    if (imageImprovements.length) console.log(`Image improvements: ${imageImprovements.join(", ")}`);

    console.log(`\n(vs run at ${prev.timestamp}${prev.commit !== "unknown" ? `, commit ${prev.commit}` : ""})`);
  } else {
    console.log("\n(no previous run in product_accuracy_history.jsonl — this is the baseline)");
  }
  console.log("");
}

async function main() {
  const args = parseArgs(process.argv.slice(2));
  await checkServerReachable(args.baseUrl);

  if (!fs.existsSync(LABELS_PATH)) {
    console.error(`No labels found at ${LABELS_PATH}`);
    process.exit(1);
  }
  const labels: GroundTruth[] = JSON.parse(fs.readFileSync(LABELS_PATH, "utf8"));
  const prev = loadLastHistoryEntry();

  const results = {
    training: [] as ResultItem[],
    validation: [] as ResultItem[],
    failed: [] as string[]
  };
  const perImagePct: Record<string, number> = {};

  for (const gt of labels) {
    if (gt.filename.startsWith("uploaded-")) continue; // Skip phantom
    const imgPath = getImagePath(gt.filename);
    if (!fs.existsSync(imgPath)) {
      console.warn(`Warning: Image missing from disk: ${imgPath}`);
      continue;
    }

    process.stdout.write(`Scanning ${gt.filename}... `);
    try {
      const b64 = "data:image/jpeg;base64," + fs.readFileSync(imgPath, "base64");
      const parsed = await fetchScan(args.baseUrl, b64);

      const bestMatchSku = parsed.possibleMatches?.find(m => m.isBestMatch)?.no_sku || "";
      const predictedItemName = parsed.classification?.top1_name || "";
      const predictedExpiry = parsed.ocr?.extracted_expired_date || "";

      const checks: Check[] = [
        { field: "no_sku", match: isMatch(gt.no_sku, bestMatchSku) },
        { field: "nama_item", match: isMatch(gt.nama_item, predictedItemName) },
        { field: "expiry_date", match: isMatch(gt.expiry_date, predictedExpiry) }
      ];

      const item: ResultItem = {
        gt,
        checks,
        method: parsed.classification?.method,
        confidence: parsed.classification?.top1_confidence
      };

      if (gt.filename.includes("/")) {
        results.training.push(item);
      } else {
        results.validation.push(item);
      }

      const score = checks.filter(c => c.match).length;
      perImagePct[gt.filename] = (score / checks.length) * 100;
      console.log(`done (${score}/3)`);
    } catch (err) {
      console.log(`FAILED (${(err as Error).message})`);
      results.failed.push(gt.filename);
    }
  }

  const trainAgg = aggregateFields(results.training);
  const valAgg = aggregateFields(results.validation);
  const trainClassStats = aggregateClassification(results.training);
  const valClassStats = aggregateClassification(results.validation);
  const imageCount = { training: results.training.length, validation: results.validation.length };

  printSummary(trainAgg, valAgg, trainClassStats, valClassStats, perImagePct, prev, imageCount, results.failed);

  const entry: HistoryEntry = {
    timestamp: new Date().toISOString(),
    commit: getGitCommit(),
    imageCount,
    failedImages: results.failed,
    fields: { training: trainAgg, validation: valAgg },
    classification: { training: trainClassStats, validation: valClassStats },
    perImage: perImagePct
  };
  fs.appendFileSync(HISTORY_PATH, JSON.stringify(entry) + "\n");
}

main().catch(err => {
  console.error("Fatal error:", err);
  process.exit(1);
});