#!/usr/bin/env node

// [start-readme]
//
// This script is run on a writer's machine while developing Early Access content locally. It
// updates the data and image paths to either include `early-access` or remove it.
//
// [end-readme]

const fs = require('fs')
const path = require('path')
const program = require('commander')
const walk = require('walk-sync')
const { escapeRegExp, last } = require('lodash')
const yaml = require('js-yaml')
const patterns = require('../../lib/patterns')
const earlyAccessContent = path.posix.join(process.cwd(), 'content/early-access')
const earlyAccessData = path.posix.join(process.cwd(), 'data/early-access')
const earlyAccessImages = path.posix.join(process.cwd(), 'assets/images/early-access')

program
  .description('Update data and image paths.')
  .option('-p, --path-to-early-access-content-file <PATH>', 'Path to a specific content file. Defaults to all Early Access content files if not provided.')
  .option('-a, --add', 'Add "early-access" to data and image paths.')
  .option('-r, --remove', 'Remove "early-access" from data and image paths.')
  .parse(process.argv)

if (!(program.add || program.remove)) {
  console.error('Error! Must specify either `--add` or `--remove`.')
  process.exit(1)
}

let earlyAccessContentAndDataFiles
if (program.pathToEarlyAccessContentFile) {
  earlyAccessContentAndDataFiles = path.posix.join(process.cwd(), program.pathToEarlyAccessContentFile)

  if (!fs.existsSync(earlyAccessContentAndDataFiles)) {
    console.error(`Error! ${program.pathToEarlyAccessContentFile} can't be found. Make sure the path starts with 'content/early-access'.`)
    process.exit(1)
  }
  earlyAccessContentAndDataFiles = [earlyAccessContentAndDataFiles]
} else {
  // Gather the EA content and data files
  earlyAccessContentAndDataFiles = walk(earlyAccessContent, { includeBasePath: true, directories: false })
    .concat(walk(earlyAccessData, { includeBasePath: true, directories: false }))
}

// Update the EA content and data files
earlyAccessContentAndDataFiles
  .forEach(file => {
    const oldContents = fs.readFileSync(file, 'utf8')

    // Get all the data references in each file that exist in data/early-access
    const dataRefs = (oldContents.match(patterns.dataReference) || [])
      .filter(dataRef => dataRef.includes('variables') ? checkVariable(dataRef) : checkReusable(dataRef))

    // Get all the image references in each file that exist in assets/images/early-access
    const imageRefs = (oldContents.match(patterns.imagePath) || [])
      .filter(imageRef => checkImage(imageRef))

    const replacements = {}

    if (program.add) {
      dataRefs
        // Since we're adding early-access to the path, filter for those that do not already include it
        .filter(dataRef => !dataRef.includes('data early-access.'))
        // Add to the { oldRef: newRef } replacements object
        .forEach(dataRef => {
          replacements[dataRef] = dataRef.replace(/({% data )(.*)/, '$1early-access.$2')
        })

      imageRefs
        // Since we're adding early-access to the path, filter for those that do not already include it
        .filter(imageRef => !imageRef.split('/').includes('early-access'))
        // Add to the { oldRef: newRef } replacements object
        .forEach(imageRef => {
          replacements[imageRef] = imageRef.replace('/assets/images/', '/assets/images/early-access/')
        })
    }

    if (program.remove) {
      dataRefs
        // Since we're removing early-access from the path, filter for those that include it
        .filter(dataRef => dataRef.includes('{% data early-access.'))
        // Add to the { oldRef: newRef } replacements object
        .forEach(dataRef => {
          replacements[dataRef] = dataRef.replace('early-access.', '')
        })

      imageRefs
        // Since we're removing early-access from the path, filter for those that include it
        .filter(imageRef => imageRef.split('/').includes('early-access'))
        // Add to the { oldRef: newRef } replacements object
        .forEach(imageRef => {
          replacements[imageRef] = imageRef.replace('/assets/images/early-access/', '/assets/images/')
        })
    }

    // Return early if nothing to replace
    if (!Object.keys(replacements).length) {
      return
    }

    // Make the replacement in the content
    let newContents = oldContents
    Object.entries(replacements).forEach(([oldRef, newRef]) => {
      newContents = newContents.replace(new RegExp(escapeRegExp(oldRef), 'g'), newRef)
    })

    // Write the updated content
    fs.writeFileSync(file, newContents)
  })

console.log('Done! Run "git status" in your docs-early-access checkout to see the changes.\n')

function checkVariable (dataRef) {
  // Get the data filepath from the data reference,
  // where the data reference looks like: {% data variables.foo.bar %}
  // and the data filepath looks like: data/variables/foo.yml with key of 'bar'.
  const variablePathArray = dataRef.match(/{% data (.*?) %}/)[1].split('.')
  // If early access is part of the path, remove it (since the path below already includes it)
    .filter(n => n !== 'early-access')

  // Given a string `variables.foo.bar` split into an array, we want the last segment 'bar', which is the variable key.
  // Then pop 'bar' off the array because it's not really part of the filepath.
  // The filepath we want is `variables/foo.yml`.
  const variableKey = last(variablePathArray); variablePathArray.pop()
  const variablePath = path.posix.join(earlyAccessData, `${variablePathArray.join('/')}.yml`)

  // If the variable file doesn't exist in data/early-access, exclude it
  if (!fs.existsSync(variablePath)) return false

  // If the variable file exists but doesn't have the referenced key, exclude it
  const variableFileContent = yaml.safeLoad(fs.readFileSync(variablePath, 'utf8'))
  return variableFileContent[variableKey]
}

function checkReusable (dataRef) {
  // Get the data filepath from the data reference,
  // where the data reference looks like: {% data reusables.foo.bar %}
  // and the data filepath looks like: data/reusables/foo/bar.md.
  const reusablePath = dataRef.match(/{% data (.*?) %}/)[1].split('.')
    // If early access is part of the path, remove it (since the path below already includes it)
    .filter(n => n !== 'early-access')
    .join('/')

  // If the reusable file doesn't exist in data/early-access, exclude it
  return fs.existsSync(`${path.posix.join(earlyAccessData, reusablePath)}.md`)
}

function checkImage (imageRef) {
  const imagePath = imageRef
    .replace('/assets/images/', '')
    // If early access is part of the path, remove it (since the path below already includes it)
    .replace('early-access', '')

  // If the image file doesn't exist in assets/images/early-access, exclude it
  return fs.existsSync(path.posix.join(earlyAccessImages, imagePath))
}