#41

frontend/src/lib/gekanator.ts

@@ -65,6 +65,37 @@ const originalYearOf = (post: Post): number | null => {
 }
 
 
+const originalDateOf = (post: Post): Date | null => {
+  const value = post.originalCreatedFrom || post.originalCreatedBefore
+  if (!(value))
+    return null
+
+  const date = new Date (value)
+  if (Number.isNaN (date.getTime ()))
+    return null
+
+  return date
+}
+
+
+const originalMonthOf = (post: Post): number | null => {
+  const date = originalDateOf (post)
+  if (!(date))
+    return null
+
+  return date.getMonth () + 1
+}
+
+
+const originalMonthDayOf = (post: Post): string | null => {
+  const date = originalDateOf (post)
+  if (!(date))
+    return null
+
+  return `${ date.getMonth () + 1 }-${ date.getDate () }`
+}
+
+
 const tagQuestionKey = ({ category, name }: { category: string; name: string }): string =>
     `${ category }:${ name }`
 
@@ -78,6 +109,27 @@ const tagFromQuestionKey = (key: string): { category: string; name: string } =>
 const nicoTagLabel = (name: string): string => name.replace (/^nico:/, '')
 
 
+const tagQuestionText = (category: string, label: string): string => {
+  switch (category)
+  {
+  case 'deerjikist':
+    return `作者・ニジラーとして「${ label }」に関係してゐる?`
+  case 'meme':
+    return `元ネタ・ミームとして「${ label }」に関係しさう?`
+  case 'character':
+    return `「${ label }」といふキャラクターが関係してゐる?`
+  case 'material':
+    return `素材として「${ label }」に関係してゐる?`
+  case 'nico':
+    return `ニコニコに「${ label }」といふタグが付いてゐる?`
+  case 'general':
+  case 'meta':
+  default:
+    return `内容として「${ label }」に関係しさう?`
+  }
+}
+
+
 const questionableTag = (post: Post, key: string): boolean => {
   const { category, name } = tagFromQuestionKey (key)
 
@@ -128,6 +180,14 @@ export const buildGekanatorQuestions = (posts: Post[]): GekanatorQuestion[] => {
       posts
       .map (originalYearOf)
       .filter ((year): year is number => year !== null))
+  const originalMonths = countBy (
+      posts
+      .map (originalMonthOf)
+      .filter ((month): month is number => month !== null))
+  const originalMonthDays = countBy (
+      posts
+      .map (originalMonthDayOf)
+      .filter ((monthDay): monthDay is string => monthDay !== null))
   const titleLengthMedian = median (posts.map (post => post.title?.length ?? 0))
 
   const usefulEntries = <T extends string | number> (counts: Map<T, number>) =>
@@ -146,9 +206,7 @@ export const buildGekanatorQuestions = (posts: Post[]): GekanatorQuestion[] => {
 
 	return {
 	    id:   `tag:${ key }`,
-	    text: category === 'nico'
-		? `ニコニコに「${ label }」といふタグが付いてゐる?`
-		: `内容として「${ label }」に関係しさう?`,
+	    text: tagQuestionText (category, label),
 	    kind: 'tag' as const,
 	    test: (post: Post) => questionableTag (post, String (key)) }
       })
@@ -171,6 +229,28 @@ export const buildGekanatorQuestions = (posts: Post[]): GekanatorQuestion[] => {
 	  kind: 'original_date' as const,
 	  test: (post: Post) => originalYearOf (post) === year }))
 
+  const originalMonthQuestions = usefulEntries (originalMonths)
+      .filter (([, count]) => count >= 2 && count <= Math.max (2, posts.length * .7))
+      .slice (0, 20)
+      .map (([month]) => ({
+	  id:   `original-month:${ month }`,
+	  text: `オリジナルの投稿月は ${ month } 月?`,
+	  kind: 'original_date' as const,
+	  test: (post: Post) => originalMonthOf (post) === month }))
+
+  const originalMonthDayQuestions = usefulEntries (originalMonthDays)
+      .filter (([, count]) => count >= 2 && count <= Math.max (2, posts.length * .7))
+      .slice (0, 20)
+      .map (([monthDay]) => {
+	const [month, day] = String (monthDay).split ('-')
+
+	return {
+	    id:   `original-month-day:${ monthDay }`,
+	    text: `オリジナルの投稿日は ${ month } 月 ${ day } 日?`,
+	    kind: 'original_date' as const,
+	    test: (post: Post) => originalMonthDayOf (post) === monthDay }
+      })
+
   const titleQuestions = [
       {
 	  id:   'title:long',
@@ -191,6 +271,8 @@ export const buildGekanatorQuestions = (posts: Post[]): GekanatorQuestion[] => {
   return [
       ...sourceQuestions,
       ...originalYearQuestions,
+      ...originalMonthQuestions,
+      ...originalMonthDayQuestions,
       ...titleQuestions,
       ...tagQuestions]
 }