import Database from 'better-sqlite3';
import { Invoice, InvoiceLine, InvoiceRepo } from '../invoicing';

export class SqliteInvoiceRepo implements InvoiceRepo {
  constructor(private db: Database.Database) {
    this.db.exec(`
      CREATE TABLE IF NOT EXISTS invoices (
        id TEXT PRIMARY KEY,
        customer_id TEXT NOT NULL,
        period TEXT NOT NULL,
        status TEXT NOT NULL,
        total_cents INTEGER NOT NULL,
        credit_cents INTEGER NOT NULL,
        billable_cents INTEGER NOT NULL,
        billing_type TEXT NOT NULL DEFAULT 'stripe',
        po_number TEXT,
        issued_at_ms INTEGER,
        due_at_ms INTEGER,
        paid_at_ms INTEGER
      );
      CREATE TABLE IF NOT EXISTS invoice_lines (
        invoice_id TEXT NOT NULL,
        endpoint_id TEXT NOT NULL,
        calls INTEGER NOT NULL,
        cents INTEGER NOT NULL,
        PRIMARY KEY (invoice_id, endpoint_id)
      );
    `);
  }

  save(invoice: Invoice): void {
    this.db
      .prepare(
        `INSERT INTO invoices
         (id, customer_id, period, status, total_cents, credit_cents, billable_cents,
          billing_type, po_number, issued_at_ms, due_at_ms, paid_at_ms)
         VALUES (@id, @customerId, @period, @status, @totalCents, @creditCents, @billableCents,
          @billingType, @poNumber, @issuedAtMs, @dueAtMs, @paidAtMs)
         ON CONFLICT(id) DO UPDATE SET
           customer_id = @customerId, period = @period, status = @status,
           total_cents = @totalCents, credit_cents = @creditCents,
           billable_cents = @billableCents, billing_type = @billingType,
           po_number = @poNumber, issued_at_ms = @issuedAtMs,
           due_at_ms = @dueAtMs, paid_at_ms = @paidAtMs`,
      )
      .run({
        ...invoice,
        poNumber: invoice.poNumber ?? null,
        issuedAtMs: invoice.issuedAtMs ?? null,
        dueAtMs: invoice.dueAtMs ?? null,
        paidAtMs: invoice.paidAtMs ?? null,
      });
    // Replace the line set atomically with the invoice row.
    this.db.prepare('DELETE FROM invoice_lines WHERE invoice_id = ?').run(invoice.id);
    const insert = this.db.prepare(
      'INSERT INTO invoice_lines (invoice_id, endpoint_id, calls, cents) VALUES (?, ?, ?, ?)',
    );
    for (const line of invoice.lines) {
      insert.run(invoice.id, line.endpointId, line.calls, line.cents);
    }
  }

  get(id: string): Invoice | undefined {
    const row = this.db.prepare('SELECT * FROM invoices WHERE id = ?').get(id) as
      | Record<string, unknown>
      | undefined;
    return row ? this.toInvoice(row) : undefined;
  }

  list(filter: { customerId?: string; period?: string; status?: Invoice['status'] }): Invoice[] {
    const where: string[] = [];
    const params: Record<string, string> = {};
    if (filter.customerId) {
      where.push('customer_id = @customerId');
      params.customerId = filter.customerId;
    }
    if (filter.period) {
      where.push('period = @period');
      params.period = filter.period;
    }
    if (filter.status) {
      where.push('status = @status');
      params.status = filter.status;
    }
    const sql = `SELECT * FROM invoices ${where.length ? `WHERE ${where.join(' AND ')}` : ''} ORDER BY id`;
    const rows = this.db.prepare(sql).all(params) as Record<string, unknown>[];
    return rows.map((r) => this.toInvoice(r));
  }

  nextSequence(period: string): number {
    const { n } = this.db
      .prepare('SELECT COUNT(*) AS n FROM invoices WHERE period = ?')
      .get(period) as { n: number };
    return n + 1;
  }

  private toInvoice(row: Record<string, unknown>): Invoice {
    const lines = this.db
      .prepare('SELECT endpoint_id, calls, cents FROM invoice_lines WHERE invoice_id = ? ORDER BY endpoint_id')
      .all(row.id as string) as { endpoint_id: string; calls: number; cents: number }[];
    return {
      id: row.id as string,
      customerId: row.customer_id as string,
      period: row.period as string,
      status: row.status as Invoice['status'],
      lines: lines.map(
        (l): InvoiceLine => ({ endpointId: l.endpoint_id, calls: l.calls, cents: l.cents }),
      ),
      totalCents: row.total_cents as number,
      creditCents: row.credit_cents as number,
      billableCents: row.billable_cents as number,
      billingType: row.billing_type as Invoice['billingType'],
      poNumber: (row.po_number as string | null) ?? undefined,
      issuedAtMs: (row.issued_at_ms as number | null) ?? undefined,
      dueAtMs: (row.due_at_ms as number | null) ?? undefined,
      paidAtMs: (row.paid_at_ms as number | null) ?? undefined,
    };
  }
}