#399

backend/app/services/post_import_previewer.rb

@@ -8,9 +8,11 @@ class PostImportPreviewer
     'tags',
     'parent_post_ids',
   ].freeze
-  def initialize existing: 'skip'
-    @existing = existing == 'error' ? 'error' : 'skip'
-  end
+  FETCH_WARNING_FIELDS = ['url', 'title', 'thumbnail_base'].freeze
+  EXISTING_SKIP_WARNING = '既存投稿のためスキップします．'.freeze
+  TITLE_FETCH_WARNING = 'タイトルを取得できませんでした．'.freeze
+  THUMBNAIL_FETCH_WARNING = 'サムネールを取得できませんでした．'.freeze
+  METADATA_FETCH_WARNING = 'メタデータを取得できませんでした．'.freeze
 
   def preview_rows rows:, fetch_metadata: true, metadata_cache: { }
     urls = {}
@@ -30,48 +32,60 @@ class PostImportPreviewer
     attributes = initial_attributes(row)
     provenance = initial_provenance(row)
     tag_sources = initial_tag_sources(row, attributes, provenance)
+    field_warnings = initial_field_warnings(row)
+    base_warnings = initial_base_warnings(row)
     url = row[:url].to_s.strip
     provenance['url'] = 'manual'
     normal_url = normalised_url(url)
     url_for_metadata = normal_url || url
     existing_post = normal_url.present? && Post.exists?(url: normal_url)
 
-    validation_warnings = []
     validation_errors = {}
     validation_errors[:url] = ['URL が不正です．'] if normal_url.blank?
     validation_errors[:url] = ['URL が重複しています．'] if normal_url.present? && urls.key?(normal_url)
     urls[normal_url] = true if normal_url.present?
-    if normal_url.present? && existing_post
-      if @existing == 'error'
-        validation_errors[:url] = ['既存投稿です．']
-      else
-        validation_warnings << '既存投稿のためスキップします．'
-      end
-    end
 
     if row[:metadata_url].present? && row[:metadata_url] != url_for_metadata
       clear_automatic_values!(attributes, provenance, tag_sources)
+      clear_fetch_warnings!(field_warnings)
+    end
+
+    if normal_url.present? && existing_post
+      add_field_warning!(field_warnings, 'url', EXISTING_SKIP_WARNING)
+      attributes['tags'] = merged_tags(tag_sources, provenance['tags'])
+      warnings_present = field_warnings.values.any?(&:present?) || base_warnings.present?
+      return {
+        source_row: row[:source_row],
+        url: normal_url,
+        attributes:,
+        provenance:,
+        tag_sources:,
+        metadata_url: url_for_metadata,
+        field_warnings:,
+        base_warnings:,
+        validation_errors:,
+        status: validation_errors.present? ? 'error' : (warnings_present ? 'warning' : 'ready'),
+      }
     end
 
-    fetch_warnings = Array(row[:fetch_warnings]).dup
     should_fetch = should_fetch_metadata?(fetch_metadata, row[:source_row].to_i)
-    if should_fetch && !(existing_post && @existing == 'skip')
-      metadata, fetch_warnings =
-        metadata_for(url_for_metadata, metadata_cache, fetch_warnings)
-      apply_metadata!(attributes, provenance, tag_sources, metadata)
+    if should_fetch
+      clear_fetch_warnings!(field_warnings)
+      metadata = metadata_for(url_for_metadata, metadata_cache)
+      apply_metadata!(attributes, provenance, tag_sources, metadata[:data])
+      apply_fetch_warnings!(field_warnings, metadata[:warnings])
     end
 
     attributes['url'] = url
     validate_basic_data(attributes, validation_errors)
-    validate_preview_tags(
-      merged_tags(tag_sources, provenance['tags']),
-      validation_errors,
-      validation_warnings,
-    )
+    validate_preview_tags(merged_tags(tag_sources, provenance['tags']),
+                          validation_errors,
+                          field_warnings)
     validate_parents(attributes['parent_post_ids'], validation_errors)
     attributes.delete('url')
     attributes['tags'] = merged_tags(tag_sources, provenance['tags'])
 
+    warnings_present = field_warnings.values.any?(&:present?) || base_warnings.present?
     {
       source_row: row[:source_row],
       url: normal_url || url,
@@ -79,14 +93,10 @@ class PostImportPreviewer
       provenance:,
       tag_sources:,
       metadata_url: url_for_metadata,
-      fetch_warnings:,
-      validation_warnings:,
-      warnings: fetch_warnings + validation_warnings,
+      field_warnings:,
+      base_warnings:,
       validation_errors:,
-      status: validation_errors.present? \
-                ? 'error' \
-                : ((fetch_warnings + validation_warnings).present? ? 'warning' : 'ready'),
-      existing: existing_post,
+      status: validation_errors.present? ? 'error' : (warnings_present ? 'warning' : 'ready'),
     }
   end
 
@@ -100,12 +110,12 @@ class PostImportPreviewer
   end
 
   def initial_attributes row
-    attributes = row[:attributes]&.stringify_keys || {}
+    attributes = row[:attributes]&.stringify_keys || { }
     FIELDS.to_h { |field| [field, attributes[field].to_s] }
   end
 
   def initial_provenance row
-    provenance = row[:provenance]&.stringify_keys || {}
+    provenance = row[:provenance]&.stringify_keys || { }
     FIELDS.to_h { |field| [field, provenance[field].presence || 'automatic'] }
       .merge('url' => 'manual')
   end
@@ -118,6 +128,14 @@ class PostImportPreviewer
     sources
   end
 
+  def initial_field_warnings row
+    (row[:field_warnings] || { }).stringify_keys.transform_values { |value| Array(value).map(&:to_s) }
+  end
+
+  def initial_base_warnings row
+    Array(row[:base_warnings]).map(&:to_s)
+  end
+
   def clear_automatic_values! attributes, provenance, tag_sources
     ['title', 'thumbnail_base', 'original_created_from',
      'original_created_before', 'duration'].each do |field|
@@ -127,18 +145,24 @@ class PostImportPreviewer
     attributes['tags'] = merged_tags(tag_sources, provenance['tags'])
   end
 
-  def metadata_for url, cache, previous_warnings
+  def clear_fetch_warnings! field_warnings
+    FETCH_WARNING_FIELDS.each do |field|
+      field_warnings.delete(field)
+    end
+  end
+
+  def metadata_for url, cache
     cache[url] ||= fetch_metadata(url)
   end
 
   def fetch_metadata url
-    return [{}, ['URL が空です．']] if url.blank?
+    return { data: { }, warnings: { 'url' => ['URL が空です．'] } } if url.blank?
 
-    data = PostMetadataFetcher.fetch(url).stringify_keys
-    warnings = []
-    warnings << 'タイトルを取得できませんでした．' if data['title'].blank?
-    warnings << 'サムネールを取得できませんでした．' if data['thumbnail_base'].blank?
-    [data.compact, warnings]
+    data = PostMetadataFetcher.fetch(url).stringify_keys.compact
+    warnings = { }
+    add_field_warning!(warnings, 'title', TITLE_FETCH_WARNING) if data['title'].blank?
+    add_field_warning!(warnings, 'thumbnail_base', THUMBNAIL_FETCH_WARNING) if data['thumbnail_base'].blank?
+    { data:, warnings: }
   rescue Preview::UrlSafety::UnsafeUrl,
          Preview::HttpFetcher::FetchFailed,
          Preview::HttpFetcher::ResponseTooLarge => e
@@ -146,7 +170,7 @@ class PostImportPreviewer
       "post_import_metadata_fetch_failure "\
       "#{ { error: e.class.name, message: e.message }.to_json }",
     )
-    [{}, ['メタデータを取得できませんでした．']]
+    { data: { }, warnings: { 'url' => [METADATA_FETCH_WARNING] } }
   end
 
   def apply_metadata! attributes, provenance, tag_sources, metadata
@@ -165,13 +189,26 @@ class PostImportPreviewer
     end
   end
 
+  def apply_fetch_warnings! field_warnings, warnings
+    warnings.each do |field, values|
+      values.each do |value|
+        add_field_warning!(field_warnings, field, value)
+      end
+    end
+  end
+
+  def add_field_warning! field_warnings, field, message
+    field_warnings[field] ||= []
+    field_warnings[field] << message unless field_warnings[field].include?(message)
+  end
+
   def merged_tags sources, origin = nil
     return sources['manual'].to_s if origin == 'manual'
 
     sources['automatic'].to_s
   end
 
-  def validate_preview_tags raw, errors, warnings
+  def validate_preview_tags raw, errors, field_warnings
     names = raw.to_s.split
     return if names.empty?
     if names.any? { _1.downcase.start_with?('nico:') }
@@ -185,7 +222,9 @@ class PostImportPreviewer
     errors[:tags] = ["廃止済みタグがあります: #{ deprecated.join(' ') }"] if deprecated.present?
     known = existing.reject(&:deprecated?).map(&:name)
     new_tags = parsed.uniq - known
-    warnings << "新規タグを作成します: #{ new_tags.join(' ') }" if new_tags.present?
+    if new_tags.present?
+      add_field_warning!(field_warnings, 'tags', "新規タグを作成します: #{ new_tags.join(' ') }")
+    end
   rescue Tag::SectionLiteralParseError
     errors[:tags] = ['タグ区間の記法が不正です．']
   end