#!/usr/bin/env node
// Runs Claude against the PR diff using all swedish-* skills under
// .claude/skills/ as the authoritative reference. Writes advisory
// feedback to review.md for the workflow to post as a PR comment.

import AnthropicBedrock from '@anthropic-ai/bedrock-sdk';
import { readFileSync, readdirSync, writeFileSync } from 'node:fs';
import { execSync } from 'node:child_process';
import path from 'node:path';

const SKILLS_DIR = '.claude/skills';
const ALWAYS_LOAD = 'swedish-accounting-compliance';
const MODEL = process.env.REVIEW_MODEL || 'eu.anthropic.claude-sonnet-4-6';
const MAX_DIFF_CHARS = 180_000;
const OUTPUT_FILE = 'review.md';
const COMMENT_MARKER = '<!-- swedish-compliance-review-bot -->';

function loadSkills() {
  const ids = readdirSync(SKILLS_DIR).filter((n) => n.startsWith('swedish-'));
  if (!ids.includes(ALWAYS_LOAD)) {
    throw new Error(`Required skill missing: ${ALWAYS_LOAD}`);
  }
  const primary = readFileSync(path.join(SKILLS_DIR, ALWAYS_LOAD, 'SKILL.md'), 'utf8');
  const others = ids
    .filter((id) => id !== ALWAYS_LOAD)
    .map((id) => ({
      id,
      content: readFileSync(path.join(SKILLS_DIR, id, 'SKILL.md'), 'utf8'),
    }));
  return { primary: { id: ALWAYS_LOAD, content: primary }, others };
}

function getDiff() {
  const baseRef = process.env.GITHUB_BASE_REF || 'main';
  execSync(`git fetch origin ${baseRef} --depth=1`, { stdio: 'ignore' });
  const mergeBase = execSync(`git merge-base origin/${baseRef} HEAD`).toString().trim();
  const files = execSync(`git diff --name-only ${mergeBase} HEAD`).toString().trim();
  let diff = execSync(`git diff ${mergeBase} HEAD`).toString();
  let truncated = false;
  if (diff.length > MAX_DIFF_CHARS) {
    diff = diff.slice(0, MAX_DIFF_CHARS);
    truncated = true;
  }
  return { files, diff, truncated };
}

function buildSystemPrompt({ primary, others }) {
  const otherBlocks = others
    .map((s) => `### Skill: ${s.id}\n\n${s.content}`)
    .join('\n\n---\n\n');

  return `You are reviewing a pull request in **gnubok**, a Swedish accounting SaaS built in Next.js + TypeScript on top of Supabase. Your job is to flag compliance risks against Swedish accounting law (Bokföringslagen / BFL), BFNAR, tax law, BAS 2026 chart, and VAT rules (ML 2023:200).

You have been given a corpus of compliance skills below. Use them as your authoritative source — prefer them over your training data whenever they conflict.

## Primary skill (ALWAYS consult)

### Skill: ${primary.id}

${primary.content}

---

## Topic-specific skills (consult when relevant)

${otherBlocks}

---

## Your task

1. **Route**: identify which topic-specific skills are relevant to the diff (in addition to the primary skill). State them upfront.
2. **Review**: produce advisory findings for compliance risks only. Examples of in-scope findings:
   - BAS account misuse (wrong account number for the purpose, wrong VAT account)
   - VAT errors (wrong rate, missing reverse charge marker, incorrect ruta mapping, representation moms > 300 SEK deduction)
   - Accounting guard-rail violations (editing posted entries, direct inserts into journal tables, non-storno corrections)
   - Retention / WORM violations (deleting documents linked to posted entries, mutable audit rows)
   - Period-lock bypasses
   - SIE/SRU encoding or field errors
   - Year-end / tax calculation errors (periodiseringsfond, överavskrivningar, bolagsskatt, egenavgifter)
   - Payroll errors (arbetsgivaravgifter rate, skatteavdrag, förmånsbeskattning, semesterlöneskuld)
   - Invoice field requirements (ML 17 kap 24§), kreditfaktura handling, Peppol/e-faktura
3. **Cite**: for each finding, cite the specific skill and section that supports it.
4. **Be concise**: use short bullets. No restating the diff. No style/formatting/naming comments. No praise.
5. **Allow the empty case**: if nothing in the diff touches compliance (pure UI tweak, refactor of non-accounting code, docs, tests), say so in one line and stop.
6. **Never fabricate a rule**: if uncertain, mark as "unsure" rather than asserting.

## Output format

Start with the marker literal ${COMMENT_MARKER} on its own line.

Then:

\`\`\`
## Swedish Accounting Compliance Review

**Skills consulted**: <comma-separated list including ${primary.id}>

### Findings

- **[SKILL_ID] <one-line summary>** — <1–3 sentence explanation with file:line references and the fix>.

(or: "No compliance concerns in this diff — changes are outside the scope of the Swedish accounting skills.")

### Notes (optional)

<Only if there's something worth flagging that isn't a hard finding, e.g. "worth double-checking with swedish-vat skill if the customer is EU-based">
\`\`\`

Render no emojis. Do not wrap the final output in a code fence.`;
}

function buildUserMessage({ files, diff, truncated }) {
  const note = truncated
    ? `\n\n> Note: diff exceeded ${MAX_DIFF_CHARS} chars and was truncated. Review is based on the first ${MAX_DIFF_CHARS} chars only.`
    : '';
  return `## Changed files

\`\`\`
${files}
\`\`\`

## Diff

\`\`\`diff
${diff}
\`\`\`${note}`;
}

async function main() {
  if (!process.env.AWS_ACCESS_KEY_ID || !process.env.AWS_SECRET_ACCESS_KEY) {
    writeFileSync(
      OUTPUT_FILE,
      `${COMMENT_MARKER}\n\n## Swedish Accounting Compliance Review\n\nSkipped: AWS Bedrock credentials (\`AWS_ACCESS_KEY_ID\` / \`AWS_SECRET_ACCESS_KEY\`) are not set.\n`,
    );
    console.warn('AWS credentials missing — wrote skip notice and exiting 0.');
    return;
  }

  const skills = loadSkills();
  const { files, diff, truncated } = getDiff();

  if (!diff.trim()) {
    writeFileSync(
      OUTPUT_FILE,
      `${COMMENT_MARKER}\n\n## Swedish Accounting Compliance Review\n\nNo diff detected against the base branch.\n`,
    );
    return;
  }

  const client = new AnthropicBedrock({
    awsRegion: process.env.AWS_REGION || 'eu-north-1',
    awsAccessKey: process.env.AWS_ACCESS_KEY_ID,
    awsSecretKey: process.env.AWS_SECRET_ACCESS_KEY,
  });
  const system = buildSystemPrompt(skills);
  const user = buildUserMessage({ files, diff, truncated });

  const resp = await client.messages.create({
    model: MODEL,
    max_tokens: 4096,
    system,
    messages: [{ role: 'user', content: user }],
  });

  const text = resp.content
    .filter((b) => b.type === 'text')
    .map((b) => b.text)
    .join('\n')
    .trim();

  const body = text.startsWith(COMMENT_MARKER) ? text : `${COMMENT_MARKER}\n\n${text}`;
  writeFileSync(OUTPUT_FILE, body + '\n');
  console.log(`Wrote ${OUTPUT_FILE} (${body.length} chars, model=${MODEL}).`);
}

main().catch((err) => {
  console.error('Compliance review failed:', err);
  writeFileSync(
    OUTPUT_FILE,
    `${COMMENT_MARKER}\n\n## Swedish Accounting Compliance Review\n\nReview failed: \`${String(err.message || err)}\`. This is advisory only — the PR is not blocked.\n`,
  );
  process.exit(0);
});