#!/usr/bin/env node

import { createRequire } from 'node:module';
import {
    mkdirSync,
    readFileSync,
    rmSync,
    writeFileSync,
} from 'node:fs';
import path from 'node:path';
import process from 'node:process';

import { validateRequiredProjectReports } from './coverage-integrity.mjs';

const require = createRequire(import.meta.url);
const { createCoverageMap } = require('istanbul-lib-coverage');
const libReport = require('istanbul-lib-report');
const reports = require('istanbul-reports');

const workspaceRoot = process.cwd();
const policy = JSON.parse(
    readFileSync(path.join(workspaceRoot, 'tools/coverage/coverage-policy.json'), 'utf8')
);
const outputDir = path.join(workspaceRoot, policy.reporting.mergedCoverageDir);

const validation = validateRequiredProjectReports({
    projects: policy.unitCoverage.tierA,
    workspaceRoot,
});

if (validation.errors.length > 0) {
    for (const error of validation.errors) {
        console.error(`Error: ${error}`);
    }
    process.exit(1);
}

const coverageInputs = validation.reports;
if (coverageInputs.length === 0) {
    console.error('No Tier A coverage-final.json files found under coverage/.');
    process.exit(1);
}

rmSync(outputDir, { recursive: true, force: true });
mkdirSync(outputDir, { recursive: true });

const coverageMap = createCoverageMap({});

for (const input of coverageInputs) {
    coverageMap.merge(input.data);
}

const context = libReport.createContext({
    dir: outputDir,
    coverageMap,
});

for (const reporter of ['json', 'json-summary', 'lcovonly', 'cobertura', 'html', 'text-summary']) {
    reports.create(reporter).execute(context);
}

const summary = coverageMap.getCoverageSummary().toJSON();
writeFileSync(
    path.join(outputDir, 'coverage-summary.pretty.json'),
    `${JSON.stringify(summary, null, 4)}\n`
);

console.log(`Merged ${coverageInputs.length} coverage files into ${policy.reporting.mergedCoverageDir}`);
console.log(
    `Statements: ${summary.statements.pct}% | Branches: ${summary.branches.pct}% | Functions: ${summary.functions.pct}% | Lines: ${summary.lines.pct}%`
);