import { Plugin, Transaction } from 'prosemirror-state'
import { Command as ProseMirrorCommand } from 'prosemirror-commands'
import { InputRule } from 'prosemirror-inputrules'
import { Editor } from './Editor'
import mergeDeep from './utilities/mergeDeep'
import { GlobalAttributes, RawCommands } from './types'

export interface ExtensionConfig<Options = any> {
  /**
   * Name
   */
  name: string,

  /**
   * Default options
   */
  defaultOptions?: Options,

  /**
   * Global attributes
   */
  addGlobalAttributes?: (this: {
    options: Options,
  }) => GlobalAttributes | {},

  /**
   * Raw
   */
  addCommands?: (this: {
    options: Options,
    editor: Editor,
  }) => Partial<RawCommands>,

  /**
   * Keyboard shortcuts
   */
  addKeyboardShortcuts?: (this: {
    options: Options,
    editor: Editor,
  }) => {
    [key: string]: ProseMirrorCommand,
  },

  /**
   * Input rules
   */
  addInputRules?: (this: {
    options: Options,
    editor: Editor,
  }) => InputRule[],

  /**
   * Paste rules
   */
  addPasteRules?: (this: {
    options: Options,
    editor: Editor,
  }) => Plugin[],

  /**
   * ProseMirror plugins
   */
  addProseMirrorPlugins?: (this: {
    options: Options,
    editor: Editor,
  }) => Plugin[],

  /**
   * The editor is ready.
   */
  onCreate?: ((this: {
    options: Options,
    editor: Editor,
  }) => void) | null,

  /**
   * The content has changed.
   */
  onUpdate?: ((this: {
    options: Options,
    editor: Editor,
  }) => void) | null,

  /**
   * The selection has changed.
   */
  onSelection?: ((this: {
    options: Options,
    editor: Editor,
  }) => void) | null,

  /**
   * The editor state has changed.
   */
  onTransaction?: ((
    this: {
      options: Options,
      editor: Editor,
    },
    props: {
      transaction: Transaction,
    },
  ) => void) | null,

  /**
   * The editor is focused.
   */
  onFocus?: ((
    this: {
      options: Options,
      editor: Editor,
    },
    props: {
      event: FocusEvent,
    },
  ) => void) | null,

  /**
   * The editor isn’t focused anymore.
   */
  onBlur?: ((
    this: {
      options: Options,
      editor: Editor,
    },
    props: {
      event: FocusEvent,
    },
  ) => void) | null,

  /**
   * The editor is destroyed.
   */
  onDestroy?: ((this: {
    options: Options,
    editor: Editor,
  }) => void) | null,
}

export class Extension<Options = any> {
  type = 'extension'

  config: Required<ExtensionConfig> = {
    name: 'extension',
    defaultOptions: {},
    addGlobalAttributes: () => [],
    addCommands: () => ({}),
    addKeyboardShortcuts: () => ({}),
    addInputRules: () => [],
    addPasteRules: () => [],
    addProseMirrorPlugins: () => [],
    onCreate: null,
    onUpdate: null,
    onSelection: null,
    onTransaction: null,
    onFocus: null,
    onBlur: null,
    onDestroy: null,
  }

  options!: Options

  constructor(config: ExtensionConfig<Options>) {
    this.config = {
      ...this.config,
      ...config,
    }

    this.options = this.config.defaultOptions
  }

  static create<O>(config: ExtensionConfig<O>) {
    return new Extension<O>(config)
  }

  configure(options: Partial<Options> = {}) {
    return Extension
      .create<Options>(this.config as ExtensionConfig<Options>)
      .#configure(options)
  }

  #configure = (options: Partial<Options>) => {
    this.options = mergeDeep(this.config.defaultOptions, options) as Options

    return this
  }

  extend<ExtendedOptions = Options>(extendedConfig: Partial<ExtensionConfig<ExtendedOptions>>) {
    return new Extension<ExtendedOptions>({
      ...this.config,
      ...extendedConfig,
    } as ExtensionConfig<ExtendedOptions>)
  }
}