import { readFileSync, writeFileSync, statSync } from 'fs'
import { resolve } from 'path'
import yaml from 'js-yaml'
import { flags } from './autorestic'
import { Backend, Config } from './types'
import { makeObjectKeysLowercase, rand } from './utils'
import { homedir } from 'os'

export const normalizeAndCheckBackends = (config: Config) => {
  config.backends = makeObjectKeysLowercase(config.backends)

  for (const [name, { type, path, key, ...rest }] of Object.entries(
    config.backends
  )) {
    if (!type || !path)
      throw new Error(
        `The backend "${name}" is missing some required attributes`
      )

    const tmp: any = {
      type,
      path,
      key: key || rand(128),
    }
    for (const [key, value] of Object.entries(rest))
      tmp[key.toUpperCase()] = value

    config.backends[name] = tmp as Backend
  }
}

export const normalizeAndCheckBackups = (config: Config) => {
  config.locations = makeObjectKeysLowercase(config.locations)
  const backends = Object.keys(config.backends)

  const checkDestination = (backend: string, backup: string) => {
    if (!backends.includes(backend))
      throw new Error(`Cannot find the backend "${backend}" for "${backup}"`)
  }

  for (const [name, { from, to, ...rest }] of Object.entries(
    config.locations
  )) {
    if (!from || !to)
      throw new Error(
        `The backup "${name}" is missing some required attributes`
      )

    if (Array.isArray(to)) for (const t of to) checkDestination(t, name)
    else checkDestination(to, name)
  }
}

const findConfigFile = (): string => {
  const config = '.autorestic.yml'
  const paths = [
    resolve(flags.config || ''),
    resolve('./' + config),
    homedir() + '/' + config,
  ]
  for (const path of paths) {
    try {
      const file = statSync(path)
      if (file.isFile()) return path
    } catch (e) {}
  }
  throw new Error('No Config file found')
}

export let CONFIG_FILE: string = ''

export const init = (): Config | undefined => {
  try {
    CONFIG_FILE = findConfigFile()
  } catch (e) {
    return
  }

  const raw: Config = makeObjectKeysLowercase(
    yaml.safeLoad(readFileSync(CONFIG_FILE).toString())
  )

  normalizeAndCheckBackends(raw)
  normalizeAndCheckBackups(raw)

  writeFileSync(CONFIG_FILE, yaml.safeDump(raw))

  return raw
}