Remove app/Space folder and extract model business logic into services

Relocate all 14 files from the catch-all app/Space namespace into proper
locations: data providers to Support/Formatters, installation utilities to
Services/Installation, PDF utils to Services/Pdf, module/update classes to
Services/Module and Services/Update, SiteApi trait to Traits, and helpers
to Support.

Extract ~1,400 lines of business logic from 8 fat models (Invoice, Payment,
Estimate, RecurringInvoice, Company, Customer, Expense, User) into 9 new
service classes with constructor injection. Controllers now depend on
services instead of calling static model methods. Shared item/tax creation
logic consolidated into DocumentItemService.

app/Support/helpers.php

@@ -0,0 +1,196 @@
+<?php
+
+use App\Models\CompanySetting;
+use App\Models\Currency;
+use App\Models\CustomField;
+use App\Models\Setting;
+use App\Services\Installation\InstallUtils;
+use Illuminate\Support\Str;
+
+/**
+ * Get company setting
+ *
+ * @return string
+ */
+function get_company_setting($key, $company_id)
+{
+    if (! InstallUtils::isDbCreated()) {
+        return null;
+    }
+
+    return CompanySetting::getSetting($key, $company_id);
+}
+
+/**
+ * Get app setting
+ *
+ * @param  $company_id
+ * @return string
+ */
+function get_app_setting($key)
+{
+    if (! InstallUtils::isDbCreated()) {
+        return null;
+    }
+
+    return Setting::getSetting($key);
+}
+
+/**
+ * Get page title
+ *
+ * @return string
+ */
+function get_page_title($company_id)
+{
+    if (! InstallUtils::isDbCreated()) {
+        return null;
+    }
+
+    $routeName = Route::currentRouteName();
+
+    $defaultPageTitle = 'InvoiceShelf - Self Hosted Invoicing Platform';
+
+    if ($routeName === 'customer.dashboard') {
+        $pageTitle = CompanySetting::getSetting('customer_portal_page_title', $company_id);
+
+        return $pageTitle ? $pageTitle : $defaultPageTitle;
+    }
+
+    $pageTitle = Setting::getSetting('admin_page_title');
+
+    return $pageTitle ? $pageTitle : $defaultPageTitle;
+}
+
+/**
+ * Set Active Path
+ *
+ * @param  string  $active
+ * @return string
+ */
+function set_active($path, $active = 'active')
+{
+    return call_user_func_array('Request::is', (array) $path) ? $active : '';
+}
+
+/**
+ * @return mixed
+ */
+function is_url($path)
+{
+    return call_user_func_array('Request::is', (array) $path);
+}
+
+/**
+ * @return string
+ */
+function getCustomFieldValueKey(string $type)
+{
+    switch ($type) {
+        case 'Input':
+            return 'string_answer';
+
+        case 'TextArea':
+            return 'string_answer';
+
+        case 'Phone':
+            return 'number_answer';
+
+        case 'Url':
+            return 'string_answer';
+
+        case 'Number':
+            return 'number_answer';
+
+        case 'Dropdown':
+            return 'string_answer';
+
+        case 'Switch':
+            return 'boolean_answer';
+
+        case 'Date':
+            return 'date_answer';
+
+        case 'Time':
+            return 'time_answer';
+
+        case 'DateTime':
+            return 'date_time_answer';
+
+        default:
+            return 'string_answer';
+    }
+}
+
+/**
+ * @return formated_money
+ */
+function format_money_pdf($money, $currency = null)
+{
+    $money = $money / 100;
+
+    if (! $currency) {
+        $currency = Currency::findOrFail(CompanySetting::getSetting('currency', 1));
+    }
+
+    $format_money = number_format(
+        $money,
+        $currency->precision,
+        $currency->decimal_separator,
+        $currency->thousand_separator
+    );
+
+    $currency_with_symbol = '';
+    if ($currency->swap_currency_symbol) {
+        $currency_with_symbol = $format_money.'<span style="font-family: DejaVu Sans;">'.$currency->symbol.'</span>';
+    } else {
+        $currency_with_symbol = '<span style="font-family: DejaVu Sans;">'.$currency->symbol.'</span>'.$format_money;
+    }
+
+    return $currency_with_symbol;
+}
+
+/**
+ * @param  $string
+ * @return string
+ */
+function clean_slug($model, $title, $id = 0)
+{
+    // Normalize the title
+    $slug = Str::upper('CUSTOM_'.$model.'_'.Str::slug($title, '_'));
+
+    // Get any that could possibly be related.
+    // This cuts the queries down by doing it once.
+    $allSlugs = getRelatedSlugs($model, $slug, $id);
+
+    // If we haven't used it before then we are all good.
+    if (! $allSlugs->contains('slug', $slug)) {
+        return $slug;
+    }
+
+    // Just append numbers like a savage until we find not used.
+    for ($i = 1; $i <= 10; $i++) {
+        $newSlug = $slug.'_'.$i;
+        if (! $allSlugs->contains('slug', $newSlug)) {
+            return $newSlug;
+        }
+    }
+
+    throw new Exception('Can not create a unique slug');
+}
+
+function getRelatedSlugs($type, $slug, $id = 0)
+{
+    return CustomField::select('slug')->where('slug', 'like', $slug.'%')
+        ->where('model_type', $type)
+        ->where('id', '<>', $id)
+        ->get();
+}
+
+function respondJson($error, $message)
+{
+    return response()->json([
+        'error' => $error,
+        'message' => $message,
+    ], 422);
+}