// Functions for loading the AO Manual, a hierarchy of markdown files
import chalk from 'chalk'
import inquirer from 'inquirer'
import { loadYamlMarkdownFile, lsFolder, isFolder } from './files.js'
import { repeatString, centerLines } from './strings.js'
import { headerStyle, manualTitleStyle } from './styles.js'
import { basename } from 'path'
import { marked } from 'marked'
import TerminalRenderer from 'marked-terminal'

export const AO_MANUAL_PATH = process.env.HOME + '/.ao/manual'

// Removes numbered prefix such as 12_ and .md suffix, replaces underscores with spaces, and adds titlecase
function formatManualTitleString(title) {
  // Remove .md suffix
  if(/\.md$/.exec(title)) {
    title = title.substring(0, title.length - 3)
  }
  // Remove numbered prefix e.g., 12_
  if(/^\d*_/.exec(title)) {
    title = title.split('_').slice(1).join('_')
  }
  // Replace underscores with spaces
  title = title.replaceAll('_', ' ')
  
  return title.toTitleCase() 
}
 
 marked.setOptions({
  renderer: new TerminalRenderer({
    showSectionPrefix: false,
  })
})

// Given a path and file/folder name, it returns the appropriate manual title
// If it's a folder and there is an index.js inside that has a title: field, that overrides the title
// Otherwise it's the filename or foldername, minus anything before the first underscore (_), in titlecase
async function loadManualTitle(path, fileOrFolder) {
  // If it's a .md file, check inside for a title: field
  if(/\.md$/.exec(fileOrFolder)) {
    const indexTitle = (await loadYamlMarkdownFile(path + fileOrFolder))?.meta?.title
    if(indexTitle) {
      return indexTitle
    }  
  }
  
  // If it's a folder, check for a title: field in index.md and return if exists
  if(isFolder(path + fileOrFolder)) {
    const indexPath = path + fileOrFolder + '/index.md'
    const indexTitle = (await loadYamlMarkdownFile(indexPath))?.meta?.title
    if(indexTitle) {
      return indexTitle
    }
  }
  
  // Fall back to using the file/folder name as the title
  return formatManualTitleString(fileOrFolder)
}

// Prints the specified manual page to the screen
export async function printManualPage(path, injectedTitle = '') {
  if(isFolder(path)) {
    path += '/index.md'
  }
  const dict = await loadYamlMarkdownFile(path)
  const title = injectedTitle || dict?.meta?.title || formatManualTitleString(basename(path))
  const formattedTitle = manualTitleStyle(title).centerInLine(title.length).centerInConsole()
  console.log('\n' + formattedTitle + '\n')
  const renderedMarkdown = marked(dict?.tail).wordWrap().centerInConsole()
  console.log(renderedMarkdown)
}

// Render the manual folder or a subfolder as a menu
// First the index.js is listed using the folder name or title loaded from inside the file as the menu item title
// Next, any other files not starting with a number are loaded and displayed in discovered/arbitrary order
// Next, items starting with 0_, then 1_, and so on are displayed in order. You can mix files and folders.
// Selecting a menu item renders it. For .md files it renders it and shows the same level Manual menu again.
// For folders, it goes into that folder and renders it as a manual menu folder
// This allows arbitrarily nested Manual menu folders to be explored in a standardized menu system 
export async function manualFolderAsMenu(path, menuTitle, backOption, previousMenuChoice = 0) {
  if(!isFolder(path)) {
    return false
  }
  if(path[path.length - 1] != '/') {
    path += '/'
  }
  
  let menuItems = []
  
  const folderContents = lsFolder(path)
  if(folderContents.some(fileOrFolder => fileOrFolder === 'index.md')) {
    const indexTitle = await loadManualTitle(path, 'index.md')
    
    let indexMenuItem = {}
    indexMenuItem[indexTitle] = 'index.md'
    menuItems.push(indexMenuItem)
  }
  
  let unNumberedItems = []
  let numberedItems = []
  const sortedFolderContents = folderContents.sort((a, b) => a.localeCompare(b, undefined, { numeric: true }))
  for(let i = 0; i < sortedFolderContents.length; i++) {
    const fileOrFolder = sortedFolderContents[i]
    if(fileOrFolder === 'index.md') {
      continue
    }
    const potentialNumber = fileOrFolder.split('_')[0]
    const initialNumber = parseInt(potentialNumber)
    const title = await loadManualTitle(path, fileOrFolder)
    const menuItem = {}
    menuItem[title] = fileOrFolder
    
    if(isNaN(initialNumber)) {
      unNumberedItems.push(menuItem)
    } else {
      numberedItems.push(menuItem)
    }
  }
  menuItems = menuItems.concat(unNumberedItems, numberedItems)
  
  const menuChoices = menuItems.map(menuItem => Object.keys(menuItem)[0])
  menuChoices.push(backOption)
  if(previousMenuChoice >= menuChoices.length) {
    previousMenuChoice = 0
  }
  console.log(`\n${headerStyle(menuTitle)}`)
  const answer = await inquirer.prompt({
    name: 'manual_menu',
    type: 'rawlist',
    message: 'Choose a topic:',
    choices: menuChoices,
    pageSize: menuChoices.length,
    default: previousMenuChoice
  })
  const chosenMenuIndex = menuChoices.indexOf(answer.manual_menu)
  if(answer.manual_menu === backOption) {
    return false
  }
  const chosenPath = path + Object.values(menuItems.find(menuItem => Object.keys(menuItem)[0] === answer.manual_menu))[0]
  await printManualPage(chosenPath, answer.manual_menu)
  const newBackOption = backOption === 'Back to Main Menu' ? 'Back to Table of Contents' : 'Back to ' + menuTitle
  let previousChoice = 0
  do {
    previousChoice = await manualFolderAsMenu(chosenPath, answer.manual_menu, newBackOption, previousChoice + 1)
  }
  while(previousChoice !== false)
  return chosenMenuIndex
}