/**
 * ═══════════════════════════════════════════════════════════════════════════
 * AAMOS Ledger Engine — Ekonomimodulens sanning
 * Port: 3250
 * Etapp 1 — Vertikal stängning
 * Refactored: Routes split, shared pool, API v1 versioning
 *
 * Principer (BYGGPLAN 0.001):
 *  • Determinism före AI — alla beslut reproducerbara
 *  • Audit First — varje operation genererar event + auditpost
 *  • Tenant Isolation — kunddata korsas aldrig
 *  • Hermes — alla ekonomiska händelser publiceras via event fabric
 *  • Inga direktberoenden till andra moduler
 * ═══════════════════════════════════════════════════════════════════════════
 */

import express   from 'express';
import cors      from 'cors';
import pg        from 'pg';
import { readFileSync } from 'fs';
import { fileURLToPath } from 'url';
import { dirname, join } from 'path';
import { randomUUID }    from 'crypto';
import hermes            from './hermes.mjs';
import { authMiddleware } from './auth.mjs';
import jwt from 'jsonwebtoken';
import { register as registerPeriodWorkflow } from './period-workflow.mjs';
import { register as registerReconciliation } from './reconciliation.mjs';
import { register as registerSie4Export } from './sie4-export.mjs';
import { registerCheckpoints, initCheckpointEngine } from './checkpoint-engine.mjs';

// Route modules
import registerAccounts from './routes/accounts.mjs';
import registerJournal  from './routes/journal.mjs';
import registerPeriods  from './routes/periods.mjs';
import registerReports  from './routes/reports.mjs';
import registerInvoices from './routes/invoices.mjs';
import registerExport   from './routes/export.mjs';
import registerHealth   from './routes/health.mjs';

const __dir  = dirname(fileURLToPath(import.meta.url));
const PORT   = process.env.AAMOS_LEDGER_PORT || process.env.PORT || 3250;
const { Pool } = pg;

// ── Database ─────────────────────────────────────────────────────────────────
const pool = new Pool({
  connectionString: process.env.DATABASE_URL,
  ssl: { rejectUnauthorized: false },
  max: 10,
  idleTimeoutMillis: 30000,
});

// Initialize checkpoint engine with shared pool (fixes duplicate pool)
initCheckpointEngine(pool);

async function initSchema() {
  const sql = readFileSync(join(__dir, 'schema.sql'), 'utf8');
  await pool.query(sql);
  console.log('[ledger] Schema initialiserat');
}

// ── App ───────────────────────────────────────────────────────────────────────
const app = express();
app.use(cors());
app.use((req, res, next) => { if (req.path.endsWith('/upload')) return next(); express.json()(req, res, next); });

// ── Auth Validate (unauthed, local RS256 verify) ─────────────────────────────
let _ledgerPubKey = null;
try { _ledgerPubKey = readFileSync('/opt/amos/data/keys/jwt-public.pem', 'utf8'); } catch {}
const _ledgerJwtSecret = process.env.AMOS_JWT_SECRET || process.env.JWT_SECRET || 'y8Lf__vnWpImX2lxyPo3R0WYFEgCrtmQ3r8FcCwKjAWTNsLBKhaqIrP5oGAdt31E';

app.get('/api/auth/validate', (req, res) => {
  const token = req.query.token;
  if (!token) return res.status(400).json({ ok: false, error: 'token query param required' });
  try {
    const verifyKey = _ledgerPubKey || _ledgerJwtSecret;
    const algos = _ledgerPubKey ? ['RS256'] : ['HS256'];
    const claims = jwt.verify(token, verifyKey, { algorithms: algos });
    res.json({ ok: true, claims });
  } catch (e) {
    res.status(401).json({ ok: false, error: e.message });
  }
});

app.use(authMiddleware); // E1-AUTH: JWT validation för alla övriga endpoints

// ── Context helper ────────────────────────────────────────────────────────────
function buildCtx(req, entityType = null, entityId = null, decisionSource = 'user') {
  return {
    trace_id:        req.headers['x-trace-id']       || randomUUID(),
    correlation_id:  req.headers['x-correlation-id'] || randomUUID(),
    tenant_id:       req.headers['x-tenant-id']      || req.body?.tenant_id || 'wavult-group',
    user_id:         req.headers['x-user-id']        || req.body?.user_id   || 'system',
    entity_type:     entityType,
    entity_id:       entityId,
    decision_source: decisionSource,
  };
}

// ── Audit helper ──────────────────────────────────────────────────────────────
async function writeAudit(ctx, action, before = null, after = null, client = pool) {
  await client.query(
    `INSERT INTO ledger_audit_log
       (tenant_id, trace_id, correlation_id, user_id,
        entity_type, entity_id, action, decision_source, before_state, after_state)
     VALUES ($1,$2,$3,$4,$5,$6,$7,$8,$9,$10)`,
    [
      ctx.tenant_id, ctx.trace_id, ctx.correlation_id, ctx.user_id,
      ctx.entity_type, ctx.entity_id, action, ctx.decision_source,
      before ? JSON.stringify(before) : null,
      after  ? JSON.stringify(after)  : null,
    ]
  );
}

// ══════════════════════════════════════════════════════════════════════════════
// ROUTE REGISTRATION (Refactored into modules)
// ══════════════════════════════════════════════════════════════════════════════

// Health (unauthed)
registerHealth(app, pool, PORT);

// Core ledger routes
registerAccounts(app, pool, buildCtx, writeAudit, hermes);
registerJournal(app, pool, buildCtx, writeAudit, hermes);
registerPeriods(app, pool);
registerReports(app, pool);
registerInvoices(app, pool);
registerExport(app, pool);

// ══════════════════════════════════════════════════════════════════════════════
// KUNDREGISTER — LandveX Customers & Contracts
// ══════════════════════════════════════════════════════════════════════════════

// GET /api/ledger/customers — lista kunder med avtal
app.get('/api/ledger/customers', async (req, res) => {
  try {
    const orgId = req.query.org_id || req.headers['x-tenant-id'] || 'landvex';
    const { rows } = await pool.query(`
      SELECT
        c.id, c.name, c.org_number, c.vat_number,
        c.contact_name, c.contact_email, c.contact_phone,
        c.address, c.postal_code, c.city, c.country,
        c.payment_terms_days, c.default_vat_rate, c.default_account,
        c.currency, c.notes, c.active, c.created_at,
        json_agg(
          json_build_object(
            'id', ct.id,
            'title', ct.title,
            'contract_ref', ct.contract_ref,
            'amount_excl_vat', ct.amount_excl_vat,
            'vat_rate', ct.vat_rate,
            'billing_period', ct.billing_period,
            'payment_terms_days', ct.payment_terms_days,
            'invoice_description', ct.invoice_description,
            'account_credit', ct.account_credit,
            'status', ct.status,
            'start_date', ct.start_date,
            'end_date', ct.end_date
          ) ORDER BY ct.created_at DESC
        ) FILTER (WHERE ct.id IS NOT NULL) as contracts
      FROM landvex_customers c
      LEFT JOIN landvex_contracts ct ON ct.customer_id = c.id AND ct.status = 'active'
      WHERE c.org_id = $1 AND c.active = true
      GROUP BY c.id
      ORDER BY c.name
    `, [orgId]);
    res.json({ ok: true, customers: rows });
  } catch (err) {
    res.status(500).json({ ok: false, error: err.message });
  }
});

// POST /api/ledger/customers — skapa ny kund
app.post('/api/ledger/customers', async (req, res) => {
  try {
    const {
      name, org_number, vat_number, contact_name, contact_email, contact_phone,
      address, postal_code, city, country, payment_terms_days,
      default_vat_rate, default_account, currency, notes, org_id
    } = req.body;
    if (!name) return res.status(400).json({ ok: false, error: 'name required' });
    const tenantOrgId = org_id || req.headers['x-tenant-id'] || 'landvex';
    const { rows } = await pool.query(
      `INSERT INTO landvex_customers
        (org_id, name, org_number, vat_number, contact_name, contact_email, contact_phone,
         address, postal_code, city, country, payment_terms_days,
         default_vat_rate, default_account, currency, notes)
       VALUES ($1,$2,$3,$4,$5,$6,$7,$8,$9,$10,$11,$12,$13,$14,$15,$16)
       RETURNING *`,
      [
        tenantOrgId, name,
        org_number || null, vat_number || null,
        contact_name || null, contact_email || null, contact_phone || null,
        address || null, postal_code || null, city || null,
        country || 'SE',
        payment_terms_days != null ? payment_terms_days : 30,
        default_vat_rate != null ? default_vat_rate : 25,
        default_account || '3000', currency || 'SEK',
        notes || null
      ]
    );
    res.json({ ok: true, customer: rows[0] });
  } catch (err) {
    res.status(500).json({ ok: false, error: err.message });
  }
});

// ── E1-004 Reconciliation Engine ─────────────────────────────────────────────
registerReconciliation(app, pool, buildCtx, writeAudit, hermes);

// ── E1-005 Period Close Workflow ──────────────────────────────────────────────
registerPeriodWorkflow(app, pool, buildCtx, writeAudit, hermes);

// ── E1-006 SIE4 Export ─────────────────────────────────────────────────────────────
registerSie4Export(app, pool, buildCtx, hermes);

// Checkpoint Engine (L2-001)
registerCheckpoints(app);

// ══════════════════════════════════════════════════════════════════════════════
// API v1 PREFIX (backward compatibility)
// All existing /api/ledger/* routes are also available under /api/v1/ledger/*
// ══════════════════════════════════════════════════════════════════════════════

// Create a sub-app for v1 routes
const v1App = express.Router();

// Re-register all routes on v1 router
registerHealth(v1App, pool, PORT);
registerAccounts(v1App, pool, buildCtx, writeAudit, hermes);
registerJournal(v1App, pool, buildCtx, writeAudit, hermes);
registerPeriods(v1App, pool);
registerReports(v1App, pool);
registerInvoices(v1App, pool);
registerExport(v1App, pool);

// Mount v1 routes
app.use('/api/v1', v1App);

// ── Start ─────────────────────────────────────────────────────────────────────
try {
  await initSchema();
  app.listen(PORT, () => {
    console.log(`[aamos-ledger] Ledger Engine på :${PORT}`);
    console.log(`[aamos-ledger] Hermes → redis://127.0.0.1:6379 (kanal: aamos:hermes)`);
    console.log(`[aamos-ledger] Endpoints: /api/ledger/* · /api/v1/ledger/* (versioned)`);
  });
} catch (e) {
  console.error('[aamos-ledger] Startup misslyckades:', e.message);
  process.exit(1);
}