invoicing: admin and public routes

Mounts AdminAuth (HTTP Basic on /admin/*) and adds two route groups:

- Admin (/admin/invoices): list, new form, create, show, toggle-paid.
  POST /admin/invoices builds the Invoice, renders the PDF, uploads to
  MinIO, then persists the row with the resulting pdf_key.

- Public (/i/:uuid): an HTML landing page showing client name, number,
  total, and status badge, plus /i/:uuid/pdf which 302s to a short-lived
  MinIO presigned URL. Anyone with the UUID can fetch the PDF — that's
  the whole point of the link-based delivery.

The Invoice model is required only when DATABASE_URL is set, so the
contact-form site still boots in dev without Postgres. Invoicing routes
return 503 in that mode rather than crashing on first request.

asxpio.rb

@@ -1,4 +1,5 @@
 require 'logger'
+require 'bigdecimal'
 require 'sinatra/base'
 require 'sinatra/contrib'
 require 'erubi'
@@ -10,13 +11,26 @@ begin
 rescue LoadError
 end
 
-require_relative 'lib/mailer'
-require_relative 'lib/rate_limit'
-
 $root   = __dir__
 $logger = Logger.new($stdout)
 $env    = ENV.fetch('RACK_ENV', 'development')
 
+require_relative 'lib/mailer'
+require_relative 'lib/rate_limit'
+require_relative 'lib/db'
+require_relative 'lib/admin_auth'
+require_relative 'lib/s3'
+
+# Invoice model needs a live Sequel connection at class-definition time.
+if ENV['DATABASE_URL']
+  DB.connect!
+  DB.migrate!
+  require_relative 'lib/invoice'
+  require_relative 'lib/invoice_pdf'
+else
+  $logger.warn('DATABASE_URL not set — invoicing disabled')
+end
+
 class AsxpioWeb < Sinatra::Base
   RATE_LIMIT = RateLimit.new(limit: 5, window: 3600)
 
@@ -35,6 +49,7 @@ class AsxpioWeb < Sinatra::Base
       same_site:    :lax
 
   use Rack::Protection::AuthenticityToken
+  use AdminAuth
 
   Mailer.configure!
 
@@ -116,7 +131,123 @@ class AsxpioWeb < Sinatra::Base
     erb :thanks
   end
 
+  # --- Admin: invoices ----------------------------------------------------
+
+  before '/admin/*' do
+    halt 503, 'Invoicing not configured (DATABASE_URL missing).' unless defined?(Invoice)
+  end
+
+  before '/i/*' do
+    halt 503, 'Invoicing not configured (DATABASE_URL missing).' unless defined?(Invoice)
+  end
+
+  get '/admin' do
+    redirect '/admin/invoices'
+  end
+
+  get '/admin/invoices' do
+    @page_title = 'Invoices — admin'
+    @noindex    = true
+    @invoices   = Invoice.order(Sequel.desc(:created_at)).all
+    erb :'admin/invoices/index'
+  end
+
+  get '/admin/invoices/new' do
+    @page_title  = 'New invoice — admin'
+    @noindex     = true
+    @form_errors = nil
+    @form_values = {}
+    erb :'admin/invoices/new'
+  end
+
+  post '/admin/invoices' do
+    @form_values = {
+      client_name:    params[:client_name].to_s.strip,
+      client_email:   params[:client_email].to_s.strip,
+      client_address: params[:client_address].to_s.strip,
+      currency:       params[:currency].to_s.upcase,
+      gel_rate:       params[:gel_rate].to_s.strip,
+      issued_on:      params[:issued_on].to_s.strip,
+      due_on:         params[:due_on].to_s.strip,
+      notes:          params[:notes].to_s.strip,
+      items:          (params[:items] || {}).values
+    }
+    @form_errors = validate_invoice_params(@form_values)
+
+    if @form_errors.any?
+      @page_title = 'New invoice — admin'
+      @noindex    = true
+      status 422
+      return erb :'admin/invoices/new'
+    end
+
+    invoice = Invoice.build(@form_values)
+    pdf_bytes = InvoicePdf.render(invoice)
+    pdf_key   = "invoices/#{invoice.number}-#{invoice.uuid}.pdf"
+    S3.put(pdf_key, pdf_bytes)
+    invoice.pdf_key = pdf_key
+    invoice.save_changes
+
+    redirect "/admin/invoices/#{invoice.uuid}"
+  end
+
+  get '/admin/invoices/:uuid' do
+    @invoice = Invoice[uuid: params[:uuid]] or halt 404
+    @page_title = "#{@invoice.number} — admin"
+    @noindex    = true
+    erb :'admin/invoices/show'
+  end
+
+  post '/admin/invoices/:uuid/paid' do
+    invoice = Invoice[uuid: params[:uuid]] or halt 404
+    invoice.paid_at = invoice.paid? ? nil : Time.now.utc
+    invoice.save_changes
+    redirect "/admin/invoices/#{invoice.uuid}"
+  end
+
+  # --- Public: invoice landing + PDF download -----------------------------
+
+  get '/i/:uuid' do
+    @invoice = Invoice[uuid: params[:uuid]] or halt 404
+    @page_title = "Invoice #{@invoice.number}"
+    @page_desc  = "Invoice #{@invoice.number} from IE Sergei Poljanski."
+    @noindex    = true
+    erb :invoice_public
+  end
+
+  get '/i/:uuid/pdf' do
+    invoice = Invoice[uuid: params[:uuid]] or halt 404
+    url = S3.presigned_url(invoice.pdf_key,
+                           expires_in: 300,
+                           filename:   "#{invoice.number}.pdf")
+    redirect url, 302
+  end
+
+  not_found do
+    status 404
+    'Not found'
+  end
+
   error 403 do
     'Forbidden — likely CSRF token expired. Reload the page and try again.'
   end
+
+  helpers do
+    def validate_invoice_params(v)
+      errors = {}
+      errors[:client_name]  = 'Client name required (1–200 chars)' if v[:client_name].empty? || v[:client_name].length > 200
+      errors[:client_email] = 'Valid client email required'        if v[:client_email].empty? || v[:client_email] !~ URI::MailTo::EMAIL_REGEXP
+      errors[:currency]     = 'Unsupported currency'               unless Invoice::CURRENCIES.include?(v[:currency])
+      begin
+        raise ArgumentError if v[:gel_rate].empty?
+        BigDecimal(v[:gel_rate])
+      rescue ArgumentError
+        errors[:gel_rate] = 'GEL rate must be a positive decimal'
+      end
+      items = v[:items].select { |i| i.is_a?(Hash) && !i['description'].to_s.strip.empty? }
+      errors[:items] = 'At least one line item with a description is required' if items.empty?
+      v[:items] = items
+      errors
+    end
+  end
 end