feat(api): expose import row diagnostics (#1644)

* feat(api): expose import row diagnostics

* fix(api): stabilize import row diagnostics

* fix(api): harden import row diagnostics

* fix(api): number Mint import diagnostics rows

* fix(api): enforce unique import row diagnostics

* fix(api): address import row diagnostics review

app/views/api/v1/imports/rows.json.jbuilder

@@ -0,0 +1,78 @@
+# frozen_string_literal: true
+
+mapping_summary = lambda do |type, key|
+  mapping = @row_mapping_lookup[[ type, key.to_s ]]
+
+  if mapping
+    mappable = if mapping.mappable
+      {
+        id: mapping.mappable.id,
+        type: mapping.mappable_type,
+        name: mapping.mappable.try(:name)
+      }
+    end
+
+    {
+      key: mapping.key,
+      type: mapping.type,
+      value: mapping.value,
+      create_when_empty: mapping.create_when_empty,
+      creatable: mapping.creatable?,
+      mappable: mappable
+    }
+  else
+    {
+      key: key,
+      type: type,
+      value: nil,
+      create_when_empty: false,
+      creatable: false,
+      mappable: nil
+    }
+  end
+end
+
+json.data do
+  json.array! @rows do |row|
+    json.id row.id
+    json.row_number row.source_row_number
+    json.valid row.errors.empty?
+    json.errors row.errors.full_messages
+
+    json.fields do
+      json.account row.account
+      json.date row.date
+      json.qty row.qty
+      json.ticker row.ticker
+      json.exchange_operating_mic row.exchange_operating_mic
+      json.price row.price
+      json.amount row.amount
+      json.currency row.currency
+      json.name row.name
+      json.category row.category
+      json.tags row.tags
+      json.entity_type row.entity_type
+      json.notes row.notes
+      json.active row.active
+      json.effective_date row.effective_date
+      json.conditions row.conditions
+      json.actions row.actions
+    end
+
+    json.mappings do
+      json.account mapping_summary.call("Import::AccountMapping", row.account) if row.account.present?
+      json.category mapping_summary.call("Import::CategoryMapping", row.category) if row.category.present?
+      json.account_type mapping_summary.call("Import::AccountTypeMapping", row.entity_type) if row.entity_type.present?
+      json.tags row.tags_list.reject(&:blank?).map { |tag| mapping_summary.call("Import::TagMapping", tag) }
+    end
+  end
+end
+
+json.meta do
+  json.current_page @pagy.page
+  json.next_page @pagy.next
+  json.prev_page @pagy.prev
+  json.total_pages @pagy.pages
+  json.total_count @pagy.count
+  json.per_page @per_page
+end