name: Malware & Obfuscation Scan

on:
  push:
    branches: ["**"]
  pull_request:
    branches: ["**"]
  # Allow manual triggering for ad-hoc full scans
  workflow_dispatch:
    inputs:
      scan_path:
        description: "Sub-directory to scan (leave blank for full repo)"
        required: false
        default: "."

# Prevent concurrent scans on the same ref from stepping on each other
concurrency:
  group: malware-scan-${{ github.ref }}
  cancel-in-progress: true

permissions:
  contents: read
  # Needed if you later add GitHub Code Scanning / SARIF upload
  security-events: write

jobs:
  malware-scan:
    name: Scan for malicious / obfuscated code
    runs-on: self-hosted
    timeout-minutes: 15

    steps:
      # ── 1. Checkout ────────────────────────────────────────────────────────
      - name: Checkout repository
        uses: actions/checkout@v4
        with:
          # Full history lets the scanner see every file, not just the diff.
          # For very large repos you can set fetch-depth: 1 to speed things up,
          # but you may miss injected files in unchanged paths.
          fetch-depth: 0

      # ── 2. Setup Node ──────────────────────────────────────────────────────
      - name: Set up Node.js
        uses: actions/setup-node@v4
        with:
          node-version: "20"

      # ── 3. Install scanner ─────────────────────────────────────────────────
      #    The scanner is pure Node.js stdlib — no npm install needed.
      #    We just copy the script into a known location inside the runner.
      - name: Install scanner script
        run: |
          mkdir -p "$RUNNER_TOOL_CACHE/malware-scanner"
          cp .github/scripts/scan-malware.js \
             "$RUNNER_TOOL_CACHE/malware-scanner/scan-malware.js"
          chmod +x "$RUNNER_TOOL_CACHE/malware-scanner/scan-malware.js"

      # ── 4. Run the scanner ─────────────────────────────────────────────────
      - name: Run malware scanner
        id: scan
        env:
          SCAN_JSON_OUT: ${{ runner.temp }}/scan-results.json
        run: |
          SCAN_PATH="${{ github.event.inputs.scan_path || '.' }}"
          echo "Scanning path: $SCAN_PATH"
          echo "────────────────────────────────────────"

          node "$RUNNER_TOOL_CACHE/malware-scanner/scan-malware.js" "$SCAN_PATH"
        # The script exits 0 (clean), 1 (threats found), or 2 (internal error).
        # We want the step to "succeed" so the upload-artifact step always runs,
        # but we'll fail the job in the gate step below.
        continue-on-error: true

      # ── 5. Upload JSON report as artifact (always, even on failure) ────────
      #    Retained so the full per-file, per-rule detail is always downloadable.
      #    The Telegram message below links directly to the Actions run where
      #    this artifact appears.
      - name: Upload scan report artifact
        if: always()
        uses: actions/upload-artifact@v4
        with:
          name: malware-scan-report-${{ github.sha }}
          path: ${{ runner.temp }}/scan-results.json
          retention-days: 90
          if-no-files-found: ignore

      # ── 6. Check whether any critical findings were reported ────────────────
      - name: Check for critical findings
        id: critical
        if: always()
        env:
          SCAN_JSON: ${{ runner.temp }}/scan-results.json
        run: |
          node - << 'EOF'
          const fs = require('fs');

          let findings = [];
          try {
            findings = JSON.parse(fs.readFileSync(process.env.SCAN_JSON, 'utf8'));
          } catch { /* missing file = clean run or scanner error */ }

          const criticalCount = findings.filter(f => f.severity === 'CRITICAL').length;
          fs.appendFileSync(process.env.GITHUB_OUTPUT, `count=${criticalCount}\n`);
          fs.appendFileSync(process.env.GITHUB_OUTPUT, `has_critical=${criticalCount > 0}\n`);
          console.log(`Critical findings: ${criticalCount}`);
          EOF

      # ── 7. Send Telegram notification for critical findings only ─────────────
      #    Requires two repository secrets:
      #      TELEGRAM_BOT_TOKEN  — from @BotFather  (format: 123456:ABC-xxx)
      #      TELEGRAM_CHAT_ID    — target chat/channel ID (format: -100xxxxxxxxxx)
      #
      #    Intentionally short — plain HTML mode, no code spans, no snippets.
      #    All special characters that would break MarkdownV2 are avoided entirely.
      #    Full details are in the artifact linked via the Actions run URL.
      - name: Send Telegram notification
        if: always() && steps.critical.outputs.has_critical == 'true'
        env:
          TELEGRAM_BOT_TOKEN: ${{ secrets.TELEGRAM_BOT_TOKEN }}
          TELEGRAM_CHAT_ID: ${{ secrets.TELEGRAM_CHAT_ID }}
          SCAN_JSON: ${{ runner.temp }}/scan-results.json
          GH_REPO: ${{ github.repository }}
          GH_SHA: ${{ github.sha }}
          GH_REF: ${{ github.ref_name }}
          GH_ACTOR: ${{ github.actor }}
          GH_RUN_URL: ${{ github.server_url }}/${{ github.repository }}/actions/runs/${{ github.run_id }}
        run: |
          node - << 'EOF'
          const fs    = require('fs');
          const https = require('https');

          const token  = process.env.TELEGRAM_BOT_TOKEN;
          const chatId = process.env.TELEGRAM_CHAT_ID;
          const repo   = process.env.GH_REPO;
          const sha    = process.env.GH_SHA.slice(0, 7);
          const ref    = process.env.GH_REF;
          const actor  = process.env.GH_ACTOR;
          const runUrl = process.env.GH_RUN_URL;

          // HTML-escape only the four characters HTML cares about.
          // Using HTML parse_mode means code snippets, file paths, and rule IDs
          // with special characters can never break the parser.
          const h = s => String(s)
            .replace(/&/g, '&amp;')
            .replace(/</g, '&lt;')
            .replace(/>/g, '&gt;')
            .replace(/"/g, '&quot;');

          let findings = [];
          try {
            findings = JSON.parse(fs.readFileSync(process.env.SCAN_JSON, 'utf8'));
          } catch { /* missing file = clean run or scanner error */ }

          const counts = { CRITICAL: 0, HIGH: 0, MEDIUM: 0, LOW: 0 };
          for (const f of findings) counts[f.severity] = (counts[f.severity] || 0) + 1;

          const criticalFindings = findings.filter(f => f.severity === 'CRITICAL');

          // ── Unique affected files ──────────────────────────────────────────
          const affectedFiles = [...new Set(criticalFindings.map(f => f.file))];

          // ── Build a short, fixed-size message ─────────────────────────────
          // No snippets, no descriptions — just counts, affected files, and a
          // direct link to the artifact. Stays well under 500 chars.
          let lines = [];

          lines.push('🚨 <b>Malware Scan — CRITICAL THREATS DETECTED</b>');

          lines.push('');
          lines.push(`<b>Repo:</b>   ${h(repo)}`);
          lines.push(`<b>Branch:</b> ${h(ref)}  <b>Commit:</b> ${h(sha)}`);
          lines.push(`<b>Actor:</b>  ${h(actor)}`);

          lines.push('');
          lines.push(
            `<b>Findings:</b>  ` +
            `🔴 ${counts.CRITICAL} CRITICAL  ` +
            `🟠 ${counts.HIGH} HIGH  ` +
            `🟡 ${counts.MEDIUM} MEDIUM  ` +
            `⚪ ${counts.LOW} LOW`
          );
          lines.push('');
          lines.push(`<b>Critical affected files (${affectedFiles.length}):</b>`);
          // Cap at 10 files to keep the message short
          const shown = affectedFiles.slice(0, 10);
          for (const f of shown) lines.push(`  • ${h(f)}`);
          if (affectedFiles.length > 10) {
            lines.push(`  • … and ${affectedFiles.length - 10} more`);
          }

          lines.push('');
          lines.push(`📋 <a href="${h(runUrl)}">View full run &amp; download report artifact</a>`);

          const text = lines.join('\n');

          // ── Send via Bot API (HTML parse mode) ────────────────────────────
          const body = JSON.stringify({
            chat_id:                  chatId,
            text,
            parse_mode:               'HTML',
            disable_web_page_preview: true,
          });

          const options = {
            hostname: 'api.telegram.org',
            path:     `/bot${token}/sendMessage`,
            method:   'POST',
            headers:  {
              'Content-Type':   'application/json',
              'Content-Length': Buffer.byteLength(body),
            },
          };

          const req = https.request(options, res => {
            let data = '';
            res.on('data', chunk => data += chunk);
            res.on('end', () => {
              const parsed = JSON.parse(data);
              if (!parsed.ok) {
                console.error('Telegram API error:', JSON.stringify(parsed));
                process.exit(1);
              }
              console.log('Telegram notification sent successfully.');
            });
          });
          req.on('error', err => {
            console.error('Request failed:', err.message);
            process.exit(1);
          });
          req.write(body);
          req.end();
          EOF

      # ── 8. Gate — fail the workflow if critical findings were found ─────────
      #    Runs after the Telegram step so the alert always fires first.
      - name: Fail workflow if critical threats detected
        if: always() && steps.critical.outputs.has_critical == 'true'
        run: |
          echo "::error::⛔ Critical malicious or highly-suspicious code patterns were detected."
          echo "::error::Check your Telegram channel for the summary."
          echo "::error::Download the 'malware-scan-report' artifact for full details."
          echo "::error::Do NOT merge or deploy this branch until findings are reviewed."
          exit 1

      # ── 9. (Optional) Diff-only scan on PRs for faster feedback ───────────
      #    Uncomment this block if you want a second, faster pass that only
      #    checks the files changed in the PR diff.
      #
      # - name: Diff-only scan (PR only)
      #   if: github.event_name == 'pull_request'
      #   env:
      #     SCAN_JSON_OUT: ${{ runner.temp }}/scan-results-diff.json
      #   run: |
      #     git diff --name-only origin/${{ github.base_ref }}...HEAD \
      #       | grep -E '\.(js|cjs|mjs|ts|tsx|jsx)$' \
      #       | xargs -I{} node "$RUNNER_TOOL_CACHE/malware-scanner/scan-malware.js" {}