feat: chapter function

app/utils/chapter.ts

@@ -0,0 +1,145 @@
+
+export interface ChapterItem {
+  rawTitle:string
+  title:string
+  /**
+   * the chapter content
+   */
+  text:string
+  /**
+   * the chapter number
+   */
+  number:number
+  key:string
+  indexOf:number
+}
+
+export type Chapters = ChapterItem[]
+
+function formatLines(text:string){
+  const lines = text.split('\n')
+    // .reduce<string[]>((result,line)=>{
+    //   const childLines = line.split('\r\n').map(childLine=>{
+    //       return childLine.split("\r")
+    //     })
+    //   return result.concat(
+    //     ...childLines
+    //   )
+    // },[])
+
+
+  return lines
+}
+
+
+
+export function splitChapter(text:string){
+  const lines = formatLines(text)
+  
+  const chapters:Chapters = []
+
+  /**
+   * the chapters array index, not the chapter number
+   * like pointer
+   */
+  let chapterIndex = -1
+  let offset = 0
+  for(let lineIndex=0;lineIndex<lines.length;lineIndex++) {
+    const lineText = lines[lineIndex]
+    offset += lineText.length
+    if(!lineText || !lineText.trim()) {
+      continue
+    }
+    const title = getChapterTitle(lineText)
+    if(title!==null){
+      ++chapterIndex;
+      chapters[chapterIndex] = {
+        rawTitle:lineText,
+        title,
+        text:"",
+        number:chapterIndex+1,
+        key:generateKey(),
+        indexOf:Math.max(0,offset-1)
+      }
+      // lastLineOffset+=lineText.length
+      continue
+    }
+    if(chapterIndex===-1) {
+      chapterIndex = 0
+      chapters[chapterIndex] = {
+        title:"",
+        rawTitle:"",
+        text:lineText+"\n",
+        number:1,
+        key:generateKey(),
+        indexOf:Math.max(0,offset)
+      }
+      continue
+    }
+    const chapter = chapters[chapterIndex]
+    chapter.text += lineText
+    // chapter.indexOf = lastLineOffset+lineText.length
+    // lastLineOffset = chapter.indexOf
+  }
+
+  console.info("chapters",chapters)
+  return chapters
+}
+
+function getChapterTitle(text:string){
+  const matchTitleSpecialCharRegexp = /[^\s\da-z]/i
+  // example: Chapter 1
+  if(/^chapter\s*\d+/i.test(text)) {
+    return text.replace(/^chapter\s*\d+/i,"").replace(matchTitleSpecialCharRegexp,"").trim()
+  }
+
+  // example Chapter: title
+  // example Chapter 2: title
+  // example Chapter one: title
+  // example Chapter One: "title"
+  // example Chapter One: [title]
+  // example Chapter III: [title]
+  // example Chapter: [title]
+  if(/^chapter\s*.*[^\s\da-z]([\s\da-z]+)/i.test(text)) {
+    return text.replace(/^chapter\s*.*[^\s\da-z]([\s\da-z]+)/i,"$1").replace(matchTitleSpecialCharRegexp,"").trim()
+  }
+
+  if(
+    /^([-=+<>#\*])\1{2,}$/.test(text)
+  ) {
+    return ""
+  }
+
+  if(/SPLIT\s*CHAPTER/.test(text)) return ""
+  if(/CHAPTER\s*SPLIT/.test(text)) return ""
+
+  return null
+}
+
+function randomString(count:number) {
+    const seeds = ['0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P','Q','R','S','T','U','V','W','X','Y','Z','a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z'];
+    return Array(count).fill("").map(()=>{
+      const index = Math.floor(Math.random() * 1000) % (seeds.length)
+      return seeds[index]
+    }).join("")
+
+}
+
+const generateKey = () => randomString(20)
+
+export async function readFile(file:File){
+  const reader = new FileReader()
+      
+  const promise = new Promise<string>((resolve,reject)=>{
+    reader.addEventListener("loadend",function(){
+      let txt = reader.result as unknown as string
+      txt = txt.replace('\r\n','\n').replace('\r','\n')
+      resolve(reader.result as unknown as string)
+    })
+    reader.addEventListener("error",reject)
+  })
+
+  reader.readAsText(file,"utf-8")
+
+  return promise
+}