#!/usr/bin/env node
const fse = require('fs-extra')
const minimatch = require('minimatch')
const select = require('unist-util-select')
const {parseFile, jsonify, stringify} = require('..')
const YAML = require('js-yaml')

const yargs = require('yargs')
  .usage('$0 [options] [<filenames>]')
  .option('syntax', {
    desc: `The specific syntax to parse as, or 'auto' to determine from the filename.`,
    alias: 's',
  })
  .option('format', {
    desc: 'Output format',
    alias: 'f',
    default: 'json',
  })
  .option('pretty', {
    desc: 'Prettify output',
    alias: 'p',
    type: 'boolean',
  })
  .option('grep', {
    desc: 'Only include variable names that match the given glob-like pattern.',
    alias: 'g',
    type: 'string',
  })

const formatters = {
  'json': (data, {pretty}) => {
    const indent = pretty ? 2 : 0
    return JSON.stringify(data, null, ' '.repeat(indent))
  },
  'yaml': (data, {pretty}) => {
    const indent = pretty ? 2 : 0
    const opts = {indent}
    return YAML.safeDump(data, 'utf8', opts)
  },
}

const options = yargs.argv
const args = options._

const STDIN = '/dev/stdin'
const DASH = '-'
const STDIN_OVERRIDES = {
  syntax: options.syntax === 'auto' ? 'scss' : options.syntax
}

const reads = (args.length ? args : [STDIN])
  .map(file => file === DASH ? STDIN : file)
  .map(file => {
    const opts = file === STDIN
      ? Object.assign({}, options, STDIN_OVERRIDES)
      : options
    return parseFile(file, opts, 'utf8')
  })

const getVariables = tree => {
  return select(tree, 'stylesheet > declaration')
    .reduce((acc, node) => {
      const {name, value} = jsonify(node)
      if (name) {
        acc[name] = value
      }
      return acc
    }, {})
}

Promise.all(reads)
  .then(files => {
    return files.reduce((acc, tree) => {
      const vars = getVariables(tree)
      console.warn('found %d variable declarations in %s',
                   Object.keys(vars).length, tree.source)
      return Object.assign(acc, vars)
    }, {})
  })
  .catch(error => {
    console.error(error)
    process.exit(1)
  })
  .then(vars => {
    const {grep, format} = options
    if (grep) {
      console.warn('grepping: "%s"', grep)
      vars = Object.keys(vars)
        .filter(key => minimatch(key, grep))
        .reduce((filtered, key) => {
          filtered[key] = vars[key]
          return filtered
        }, {})
    }
    const fmt = formatters[format]
    const output = fmt(vars, options)
    console.log(output)
  })
  .catch(error => {
    console.error(error)
    process.exit(1)
  })