import * as path from 'path'
import * as fs from 'fs-extra'
import * as memFs from 'mem-fs'
import * as editor from 'mem-fs-editor'
import * as _ from 'lodash'

import { getRootPath } from '../util'

interface IFile {
  contents: Buffer | NodeJS.ReadableStream | null;
  cwd: string;
  base: string | null | undefined;
  history: string[];
  relative: string;
  dirname: string;
  basename: string;
  stem: string;
  extname: string;
  symlink: string;
  stat: fs.Stats | null;
}

interface IReadOptions {
  raw?: boolean;
}

interface IAppendOptions {
  trimEnd?: boolean;
  separator?: string;
}

interface IMemFsEditor {
  store: {
    [key: string]: IFile;
  };
  read(filePath: string, options?: IReadOptions): string | Buffer;
  readJSON(filePath: string, defaults?: JSON): JSON;
  write(filePath: string, contents: string | Buffer): string;
  writeJSON(
    filepath: string,
    contents: JSON,
    replacer?: ((key: string, value: any) => any) | undefined,
    space?: string | number | undefined
  ): string;
  append(filePath: string, contents: string | Buffer, options?: IAppendOptions): string | Buffer;
  copyTpl(from: string, to: string, context: object, templateOptions: object);
  commit(cb: () => void);
}

export default class Creator {
  fs: IMemFsEditor
  protected _rootPath: string
  private _destinationRoot: string

  constructor (sourceRoot?: string) {
    const store = memFs.create()
    this.fs = editor.create(store)
    this.sourceRoot(sourceRoot || path.join(getRootPath()))
    this.init()
  }

  init () {}

  sourceRoot (rootPath?: string) {
    if (typeof rootPath === 'string') {
      this._rootPath = path.resolve(rootPath)
    }
    if (!fs.existsSync(this._rootPath)) {
      fs.ensureDirSync(this._rootPath)
    }
    return this._rootPath
  }

  templatePath (...args: string[]): string {
    let filepath = path.join.apply(path, args)
    if (!path.isAbsolute(filepath)) {
      filepath = path.join(this._rootPath, 'templates', filepath)
    }
    return filepath
  }

  destinationRoot (rootPath?: string): string {
    if (typeof rootPath === 'string') {
      this._destinationRoot = path.resolve(rootPath)
      if (!fs.existsSync(rootPath)) {
        fs.ensureDirSync(rootPath)
      }
      process.chdir(rootPath)
    }
    return this._destinationRoot || process.cwd()
  }

  destinationPath (...args: string[]): string {
    let filepath = path.join.apply(path, args)
    if (!path.isAbsolute(filepath)) {
      filepath = path.join(this.destinationRoot(), filepath)
    }
    if (filepath.endsWith('package.json.tmpl')) {
      filepath = filepath.replace('.tmpl', '')
    }
    const basename = path.basename(filepath)
    if (basename.startsWith('_')) {
      filepath = path.join(path.dirname(filepath), basename.replace(/^_/, '.'))
    }
    return filepath
  }

  template (template: string, source: string, dest: string, data?: object, options?) {
    if (typeof dest !== 'string') {
      options = data
      data = dest
      dest = source
    }

    const src = this.templatePath(template, source)
    if (!fs.existsSync(src)) return

    this.fs.copyTpl(src, this.destinationPath(dest), Object.assign({ _ }, this, data), options)
    return this
  }

  writeGitKeepFile (dirname: string) {
    dirname = path.resolve(dirname)
    fs.writeFileSync(path.join(dirname, '.gitkeep'), 'Place hold file', 'utf8')
  }

  write () {}
}