#!/usr/bin/env bun
import * as fs from 'fs';
import * as path from 'path';
import { computeLensStats, lensEventPath, readLensEvents } from '../scripts/lenses/events';

function arg(name: string): string | undefined {
  const i = process.argv.indexOf(name);
  return i >= 0 ? process.argv[i + 1] : undefined;
}
function flag(name: string): boolean {
  return process.argv.includes(name);
}

const repoRoot = path.resolve(arg('--repo-root') ?? process.cwd());
const filePath = lensEventPath(repoRoot, { slug: arg('--project') });
if (process.argv.includes('--purge')) {
  if (!flag('--yes')) throw new Error(`Refusing to purge ${filePath} without --yes`);
  fs.rmSync(filePath, { force: true });
  process.stdout.write(`Purged ${filePath}\n`);
  process.exit(0);
}

const { events, parse_errors } = readLensEvents(filePath);
const stats = computeLensStats(events, parse_errors);
if (flag('--json')) {
  process.stdout.write(JSON.stringify({ path: filePath, ...stats }, null, 2) + '\n');
  process.exit(0);
}

process.stdout.write(`LENS_STATS: ${events.length} events analyzed (${parse_errors} parse errors)\n`);
const lenses = [...new Set([...Object.keys(stats.runs), ...Object.keys(stats.findings)])].sort();
if (lenses.length === 0) {
  process.stdout.write('No lens history for this project.\n');
  process.exit(0);
}
process.stdout.write('Lens                         Runs  Findings  Novel  Confirmed  Avg latency  Avg cost  Insufficient\n');
for (const lens of lenses) {
  const run = stats.runs[lens] ?? { invocations: 0, total_wall_clock_ms: 0, total_cost_usd: 0, cost_samples: 0, insufficient_evidence: 0 };
  const finding = stats.findings[lens] ?? { total: 0, novel_vs_tech: 0, confirmed_validity: 0 };
  const latency = run.invocations ? `${Math.round(run.total_wall_clock_ms / run.invocations / 1000)}s` : '-';
  const cost = run.cost_samples ? `$${(run.total_cost_usd / run.cost_samples).toFixed(2)}` : '-';
  process.stdout.write(
    `${lens.padEnd(28)} ${String(run.invocations).padStart(4)}  ${String(finding.total).padStart(8)}  ${String(finding.novel_vs_tech).padStart(5)}  ${String(finding.confirmed_validity).padStart(9)}  ${latency.padStart(11)}  ${cost.padStart(8)}  ${String(run.insufficient_evidence).padStart(12)}\n`,
  );
}