/**
 * Coverage gate for CI.
 *
 * Reads coverage-summary.json (Vitest --coverage output) and fails
 * if overall line coverage drops below the configured threshold.
 *
 * Usage:
 *   pnpm test:coverage
 *   node scripts/ci/check-coverage-delta.mjs
 *
 * Environment variable overrides:
 *   COVERAGE_THRESHOLD  – minimum line coverage % (default: 65)
 *   COVERAGE_FILE       – path to coverage-summary.json
 */

import { readFileSync } from "node:fs";

const THRESHOLD = Number(process.env.COVERAGE_THRESHOLD ?? 65);
const COVERAGE_FILE =
  process.env.COVERAGE_FILE ?? "coverage/coverage-summary.json";

let summary;
try {
  summary = JSON.parse(readFileSync(COVERAGE_FILE, "utf8"));
} catch (err) {
  console.error(`Could not read ${COVERAGE_FILE}: ${err.message}`);
  console.error("Run `pnpm test:coverage` first.");
  process.exit(1);
}

const total = summary.total;
if (!total) {
  console.error(`No "total" key in ${COVERAGE_FILE}`);
  process.exit(1);
}

const linePct = total.lines?.pct ?? 0;
const branchPct = total.branches?.pct ?? 0;
const fnPct = total.functions?.pct ?? 0;
const stmtPct = total.statements?.pct ?? 0;

console.log("\n--- Coverage Report ---\n");
console.log(`  Lines:      ${linePct.toFixed(2)}%`);
console.log(`  Branches:   ${branchPct.toFixed(2)}%`);
console.log(`  Functions:  ${fnPct.toFixed(2)}%`);
console.log(`  Statements: ${stmtPct.toFixed(2)}%`);
console.log(`\n  Threshold:  ${THRESHOLD}% (lines)\n`);

if (linePct < THRESHOLD) {
  console.error(
    `FAILED: Line coverage ${linePct.toFixed(2)}% is below the ${THRESHOLD}% threshold`
  );
  process.exit(1);
} else {
  console.log(
    `PASSED: Line coverage ${linePct.toFixed(2)}% meets the ${THRESHOLD}% threshold`
  );
}