/**
 * routes/journal.mjs — Journal entries (verifikationer)
 */

export default function registerJournal(app, pool, buildCtx, writeAudit, hermes) {
  // POST /api/ledger/journal — skapa verifikation (draft)
  app.post('/api/ledger/journal', async (req, res) => {
    const ctx = buildCtx(req, 'journal_entry');
    const {
      entry_date, description, reference, source_type = 'manual',
      source_id, lines = [], period, fiscal_year, metadata = {}
    } = req.body;

    if (!entry_date || !description || lines.length < 2) {
      return res.status(400).json({ ok: false, error: 'entry_date, description, minst 2 rader krävs' });
    }

    // Validera dubbel bokföring
    const totalDebit  = lines.reduce((s, l) => s + (parseFloat(l.debit)  || 0), 0);
    const totalCredit = lines.reduce((s, l) => s + (parseFloat(l.credit) || 0), 0);
    if (Math.abs(totalDebit - totalCredit) > 0.01) {
      return res.status(400).json({
        ok: false,
        error: `Dubbelbokföring bruten: debet ${totalDebit.toFixed(2)} ≠ kredit ${totalCredit.toFixed(2)}`
      });
    }

    const entryDate = new Date(entry_date);
    const fy  = fiscal_year || entryDate.getFullYear();
    const per = period      || `${fy}-${String(entryDate.getMonth() + 1).padStart(2,'0')}`;

    const client = await pool.connect();
    try {
      await client.query('BEGIN');

      // Kontrollera att perioden inte är stängd
      const { rows: periodCheck } = await client.query(
        `SELECT status FROM ledger_periods WHERE tenant_id=$1 AND period=$2`,
        [ctx.tenant_id, per]
      );
      if (periodCheck.length > 0 && periodCheck[0].status === 'closed') {
        await client.query('ROLLBACK');
        client.release();
        return res.status(409).json({ ok: false, error: `Period ${per} är stängd — inga nya verifikationer tillåtna`, code: 'PERIOD_CLOSED' });
      }

      const { rows } = await client.query(
        `INSERT INTO ledger_journal_entries
           (tenant_id, fiscal_year, period, entry_date, description, reference,
            source_type, source_id, status, trace_id, correlation_id, user_id,
            decision_source, metadata)
         VALUES ($1,$2,$3,$4,$5,$6,$7,$8,'draft',$9,$10,$11,$12,$13)
         RETURNING *`,
        [ctx.tenant_id, fy, per, entry_date, description, reference,
         source_type, source_id, ctx.trace_id, ctx.correlation_id,
         ctx.user_id, ctx.decision_source, JSON.stringify(metadata)]
      );
      const entry = rows[0];
      ctx.entity_id = entry.id;

      // Lägg in rader
      const insertedLines = [];
      for (let i = 0; i < lines.length; i++) {
        const l = lines[i];
        if (!l.account_number) {
          throw new Error(`Rad ${i+1}: account_number saknas`);
        }
        if ((l.debit == null) === (l.credit == null)) {
          throw new Error(`Rad ${i+1}: ange antingen debit ELLER credit, inte båda/ingen`);
        }
        const { rows: lr } = await client.query(
          `INSERT INTO ledger_journal_lines
             (entry_id, tenant_id, line_number, account_number, account_name,
              debit, credit, currency, amount_base, vat_code, vat_amount,
              cost_center, project_code, description, metadata)
           VALUES ($1,$2,$3,$4,$5,$6,$7,$8,$9,$10,$11,$12,$13,$14,$15)
           RETURNING *`,
          [entry.id, ctx.tenant_id, i+1, l.account_number, l.account_name,
           l.debit || null, l.credit || null,
           l.currency || 'SEK', l.amount_base || (l.debit || l.credit),
           l.vat_code || null, l.vat_amount || null,
           l.cost_center || null, l.project_code || null,
           l.description || null, JSON.stringify(l.metadata || {})]
        );
        insertedLines.push(lr[0]);
      }

      await writeAudit(ctx, 'created', null, { entry, lines: insertedLines }, client);
      await client.query('COMMIT');

      await hermes.emit('finance.journal.created', ctx, {
        entry_id: entry.id, period: per, fiscal_year: fy,
        total_debit: totalDebit, description, source_type,
      });

      res.status(201).json({ ok: true, entry, lines: insertedLines });
    } catch (e) {
      await client.query('ROLLBACK');
      res.status(400).json({ ok: false, error: e.message });
    } finally {
      client.release();
    }
  });

  // POST /api/ledger/journal/:id/post — konterar verifikation (draft → posted)
  app.post('/api/ledger/journal/:id/post', async (req, res) => {
    const { id } = req.params;
    const ctx = buildCtx(req, 'journal_entry', id);
    const client = await pool.connect();
    try {
      await client.query('BEGIN');

      const { rows } = await client.query(
        `SELECT * FROM ledger_journal_entries WHERE id=$1 AND tenant_id=$2`,
        [id, ctx.tenant_id]
      );
      if (!rows.length) return res.status(404).json({ ok: false, error: 'Verifikation hittades inte' });

      const before = rows[0];
      if (before.status !== 'draft') {
        return res.status(409).json({ ok: false, error: `Kan inte kontera: status är '${before.status}'` });
      }

      // Hämta rader för re-validering
      const { rows: lines } = await client.query(
        `SELECT * FROM ledger_journal_lines WHERE entry_id=$1 ORDER BY line_number`,
        [id]
      );
      const td = lines.reduce((s,l) => s + (parseFloat(l.debit)  || 0), 0);
      const tc = lines.reduce((s,l) => s + (parseFloat(l.credit) || 0), 0);
      if (Math.abs(td - tc) > 0.01) throw new Error(`Dubbelbokföring bruten vid kontering: ${td} ≠ ${tc}`);

      // Tilldela löpnummer
      const { rows: seqRows } = await client.query(
        `SELECT nextval('ledger_entry_number_seq') AS num`
      );
      const entry_number = seqRows[0].num;

      const { rows: updated } = await client.query(
        `UPDATE ledger_journal_entries
         SET status='posted', posted_at=NOW(), entry_number=$1
         WHERE id=$2 AND tenant_id=$3
         RETURNING *`,
        [entry_number, id, ctx.tenant_id]
      );
      const after = updated[0];

      await writeAudit(ctx, 'posted', before, after, client);
      await client.query('COMMIT');

      await hermes.emit('finance.journal.posted', ctx, {
        entry_id: id, entry_number, period: after.period,
        fiscal_year: after.fiscal_year,
      });

      res.json({ ok: true, entry: after });
    } catch (e) {
      await client.query('ROLLBACK');
      res.status(400).json({ ok: false, error: e.message });
    } finally {
      client.release();
    }
  });

  // GET /api/ledger/journal — lista verifikationer
  app.get('/api/ledger/journal', async (req, res) => {
    const tenant_id = req.headers['x-tenant-id'] || 'wavult-group';
    const { period, period_from, period_to, fiscal_year, status, source_type, search, limit = 50, offset = 0 } = req.query;
    const conditions = ['e.tenant_id = $1'];
    const params = [tenant_id];
    let idx = 2;

    if (fiscal_year)   { conditions.push(`e.fiscal_year = $${idx++}`);      params.push(parseInt(fiscal_year)); }
    if (period)        { conditions.push(`e.period = $${idx++}`);            params.push(period); }
    else if (period_from && period_to) {
      conditions.push(`e.period >= $${idx++}`); params.push(period_from);
      conditions.push(`e.period <= $${idx++}`); params.push(period_to);
    } else if (period_from) { conditions.push(`e.period >= $${idx++}`);   params.push(period_from); }
    else if (period_to)     { conditions.push(`e.period <= $${idx++}`);   params.push(period_to); }
    if (status)        { conditions.push(`e.status = $${idx++}`);            params.push(status); }
    if (source_type)   { conditions.push(`e.source_type = $${idx++}`);      params.push(source_type); }
    if (search)        { conditions.push(`(e.description ILIKE $${idx} OR e.reference ILIKE $${idx} OR EXISTS (SELECT 1 FROM ledger_journal_lines ll WHERE ll.entry_id = e.id AND (ll.account_number ILIKE $${idx} OR ll.account_name ILIKE $${idx})))`); idx++; params.push(`%${search}%`); }

    try {
      const whereClause = conditions.join(" AND ");
      const [{ rows }, countRes] = await Promise.all([
        pool.query(
          `SELECT e.*, json_agg(l ORDER BY l.line_number) AS lines
           FROM ledger_journal_entries e
           LEFT JOIN ledger_journal_lines l ON l.entry_id = e.id
           WHERE ${whereClause}
           GROUP BY e.id
           ORDER BY e.entry_date DESC, e.created_at DESC
           LIMIT $${idx++} OFFSET $${idx}`,
          [...params, parseInt(limit), parseInt(offset)]
        ),
        pool.query(
          `SELECT COUNT(DISTINCT e.id) AS total
           FROM ledger_journal_entries e
           LEFT JOIN ledger_journal_lines l ON l.entry_id = e.id
           WHERE ${whereClause}`,
          params
        )
      ]);
      const total = parseInt(countRes.rows[0].total);
      res.json({ ok: true, entries: rows, count: rows.length, total, pages: Math.ceil(total / parseInt(limit)), offset: parseInt(offset), limit: parseInt(limit) });
    } catch (e) {
      res.status(500).json({ ok: false, error: e.message });
    }
  });

  // POST /api/ledger/journal/:id/void — makulera verifikation
  app.post('/api/ledger/journal/:id/void', async (req, res) => {
    const { id } = req.params;
    const ctx = buildCtx(req, 'journal_entry', id);
    const { reason = 'Manuell makulering' } = req.body;
    const client = await pool.connect();
    try {
      await client.query('BEGIN');
      const { rows } = await client.query(
        'SELECT * FROM ledger_journal_entries WHERE id=$1 AND tenant_id=$2',
        [id, ctx.tenant_id]
      );
      if (!rows[0]) {
        await client.query('ROLLBACK');
        return res.status(404).json({ ok: false, error: 'Verifikation ej funnen' });
      }
      const entry = rows[0];
      if (entry.status === 'voided') {
        await client.query('ROLLBACK');
        return res.status(409).json({ ok: false, error: 'Verifikation är redan makulerad' });
      }
      const before = { status: entry.status };
      await client.query(
        `UPDATE ledger_journal_entries SET status='voided', metadata=metadata || $1::jsonb WHERE id=$2`,
        [JSON.stringify({ voided_at: new Date().toISOString(), voided_reason: reason, voided_by: ctx.user_id }), id]
      );
      await writeAudit(ctx, 'journal.void', before, { status: 'voided', reason }, client);
      await client.query('COMMIT');
      await hermes.emit('ledger.journal.voided', ctx, { entry_id: id, reason });
      res.json({ ok: true, entry_id: id, status: 'voided' });
    } catch (e) {
      await client.query('ROLLBACK');
      res.status(500).json({ ok: false, error: e.message });
    } finally {
      client.release();
    }
  });
}