import crel from "crelt"
import {lift, joinUp, selectParentNode, wrapIn, setBlockType} from "prosemirror-commands"
import {undo, redo} from "prosemirror-history"
import {EditorView} from "prosemirror-view"
import {EditorState, Transaction, NodeSelection} from "prosemirror-state"
import {NodeType, Attrs} from "prosemirror-model"

import {getIcon} from "./icons"

/// The types defined in this module aren't the only thing you can
/// display in your menu. Anything that conforms to this interface can
/// be put into a menu structure.
export interface MenuElement {
  /// Render the element for display in the menu. Must return a DOM
  /// element and a function that can be used to update the element to
  /// a new state. The `update` function must return false if the
  /// update hid the entire element.
  render(pm: EditorView): {dom: HTMLElement, update: (state: EditorState) => boolean}
}

const prefix = "ProseMirror-menu"

/// An icon or label that, when clicked, executes a command.
export class MenuItem implements MenuElement {
  /// Create a menu item.
  constructor(
    /// The spec used to create this item.
    readonly spec: MenuItemSpec
  ) {}

  /// Renders the icon according to its [display
  /// spec](#menu.MenuItemSpec.display), and adds an event handler which
  /// executes the command when the representation is clicked.
  render(view: EditorView) {
    let spec = this.spec
    let dom = spec.render ? spec.render(view)
        : spec.icon ? getIcon(view.root, spec.icon)
        : spec.label ? crel("div", null, translate(view, spec.label))
        : null
    if (!dom) throw new RangeError("MenuItem without icon or label property")
    if (spec.title) {
      const title = (typeof spec.title === "function" ? spec.title(view.state) : spec.title)
      ;(dom as HTMLElement).setAttribute("title", translate(view, title))
    }
    if (spec.class) dom.classList.add(spec.class)
    if (spec.css) dom.style.cssText += spec.css

    dom.addEventListener("mousedown", e => {
      e.preventDefault()
      if (!dom!.classList.contains(prefix + "-disabled"))
        spec.run(view.state, view.dispatch, view, e)
    })

    function update(state: EditorState) {
      if (spec.select) {
        let selected = spec.select(state)
        dom!.style.display = selected ? "" : "none"
        if (!selected) return false
      }
      let enabled = true
      if (spec.enable) {
        enabled = spec.enable(state) || false
        setClass(dom!, prefix + "-disabled", !enabled)
      }
      if (spec.active) {
        let active = enabled && spec.active(state) || false
        setClass(dom!, prefix + "-active", active)
      }
      return true
    }

    return {dom, update}
  }
}

function translate(view: EditorView, text: string): string {
  return (view as any)._props.translate ? (view as any)._props.translate(text) : text
}

/// Specifies an icon. May be either an SVG icon, in which case its
/// `path` property should be an [SVG path
/// spec](https://developer.mozilla.org/en-US/docs/Web/SVG/Attribute/d),
/// and `width` and `height` should provide the viewbox in which that
/// path exists. Alternatively, it may have a `text` property
/// specifying a string of text that makes up the icon, with an
/// optional `css` property giving additional CSS styling for the
/// text. _Or_ it may contain `dom` property containing a DOM node.
export type IconSpec = {path: string, width: number, height: number} | {text: string, css?: string} | {dom: Node}

/// The configuration object passed to the `MenuItem` constructor.
export interface MenuItemSpec {
  /// The function to execute when the menu item is activated.
  run: (state: EditorState, dispatch: (tr: Transaction) => void, view: EditorView, event: Event) => void

  /// Optional function that is used to determine whether the item is
  /// appropriate at the moment. Deselected items will be hidden.
  select?: (state: EditorState) => boolean

  /// Function that is used to determine if the item is enabled. If
  /// given and returning false, the item will be given a disabled
  /// styling.
  enable?: (state: EditorState) => boolean

  /// A predicate function to determine whether the item is 'active' (for
  /// example, the item for toggling the strong mark might be active then
  /// the cursor is in strong text).
  active?: (state: EditorState) => boolean

  /// A function that renders the item. You must provide either this,
  /// [`icon`](#menu.MenuItemSpec.icon), or [`label`](#MenuItemSpec.label).
  render?: (view: EditorView) => HTMLElement

  /// Describes an icon to show for this item.
  icon?: IconSpec

  /// Makes the item show up as a text label. Mostly useful for items
  /// wrapped in a [drop-down](#menu.Dropdown) or similar menu. The object
  /// should have a `label` property providing the text to display.
  label?: string

  /// Defines DOM title (mouseover) text for the item.
  title?: string | ((state: EditorState) => string)

  /// Optionally adds a CSS class to the item's DOM representation.
  class?: string

  /// Optionally adds a string of inline CSS to the item's DOM
  /// representation.
  css?: string
}

let lastMenuEvent: {time: number, node: null | Node} = {time: 0, node: null}
function markMenuEvent(e: Event) {
  lastMenuEvent.time = Date.now()
  lastMenuEvent.node = e.target as Node
}
function isMenuEvent(wrapper: HTMLElement) {
  return Date.now() - 100 < lastMenuEvent.time &&
    lastMenuEvent.node && wrapper.contains(lastMenuEvent.node)
}

/// A drop-down menu, displayed as a label with a downwards-pointing
/// triangle to the right of it.
export class Dropdown implements MenuElement {
  /// @internal
  content: readonly MenuElement[]

  /// Create a dropdown wrapping the elements.
  constructor(
    content: readonly MenuElement[] | MenuElement,
    /// @internal
    readonly options: {
      /// The label to show on the drop-down control.
      label?: string

      /// Sets the
      /// [`title`](https://developer.mozilla.org/en-US/docs/Web/HTML/Global_attributes/title)
      /// attribute given to the menu control.
      title?: string

      /// When given, adds an extra CSS class to the menu control.
      class?: string

      /// When given, adds an extra set of CSS styles to the menu control.
      css?: string
    } = {}) {
    this.options = options || {}
    this.content = Array.isArray(content) ? content : [content]
  }

  /// Render the dropdown menu and sub-items.
  render(view: EditorView) {
    let content = renderDropdownItems(this.content, view)
    let win = view.dom.ownerDocument.defaultView || window

    let label = crel("div", {class: prefix + "-dropdown " + (this.options.class || ""),
                             style: this.options.css},
                     translate(view, this.options.label || ""))
    if (this.options.title) label.setAttribute("title", translate(view, this.options.title))
    let wrap = crel("div", {class: prefix + "-dropdown-wrap"}, label)
    let open: {close: () => boolean, node: HTMLElement} | null = null
    let listeningOnClose: (() => void) | null = null
    let close = () => {
      if (open && open.close()) {
        open = null
        win.removeEventListener("mousedown", listeningOnClose!)
      }
    }
    label.addEventListener("mousedown", e => {
      e.preventDefault()
      markMenuEvent(e)
      if (open) {
        close()
      } else {
        open = this.expand(wrap, content.dom)
        win.addEventListener("mousedown", listeningOnClose = () => {
          if (!isMenuEvent(wrap)) close()
        })
      }
    })

    function update(state: EditorState) {
      let inner = content.update(state)
      wrap.style.display = inner ? "" : "none"
      return inner
    }

    return {dom: wrap, update}
  }

  /// @internal
  expand(dom: HTMLElement, items: readonly Node[]) {
    let menuDOM = crel("div", {class: prefix + "-dropdown-menu " + (this.options.class || "")}, items)

    let done = false
    function close(): boolean {
      if (done) return false
      done = true
      dom.removeChild(menuDOM)
      return true
    }
    dom.appendChild(menuDOM)
    return {close, node: menuDOM}
  }
}

function renderDropdownItems(items: readonly MenuElement[], view: EditorView) {
  let rendered = [], updates = []
  for (let i = 0; i < items.length; i++) {
    let {dom, update} = items[i].render(view)
    rendered.push(crel("div", {class: prefix + "-dropdown-item"}, dom))
    updates.push(update)
  }
  return {dom: rendered, update: combineUpdates(updates, rendered)}
}

function combineUpdates(
  updates: readonly ((state: EditorState) => boolean)[],
  nodes: readonly HTMLElement[]
) {
  return (state: EditorState) => {
    let something = false
    for (let i = 0; i < updates.length; i++) {
      let up = updates[i](state)
      nodes[i].style.display = up ? "" : "none"
      if (up) something = true
    }
    return something
  }
}

/// Represents a submenu wrapping a group of elements that start
/// hidden and expand to the right when hovered over or tapped.
export class DropdownSubmenu implements MenuElement {
  /// @internal
  content: readonly MenuElement[]

  /// Creates a submenu for the given group of menu elements. The
  /// following options are recognized:
  constructor(
    content: readonly MenuElement[] | MenuElement,
    /// @internal
    readonly options: {
      /// The label to show on the submenu.
      label?: string
    } = {}
  ) {
    this.content = Array.isArray(content) ? content : [content]
  }

  /// Renders the submenu.
  render(view: EditorView) {
    let items = renderDropdownItems(this.content, view)
    let win = view.dom.ownerDocument.defaultView || window

    let label = crel("div", {class: prefix + "-submenu-label"}, translate(view, this.options.label || ""))
    let wrap = crel("div", {class: prefix + "-submenu-wrap"}, label,
                   crel("div", {class: prefix + "-submenu"}, items.dom))
    let listeningOnClose: (() => void) | null = null
    label.addEventListener("mousedown", e => {
      e.preventDefault()
      markMenuEvent(e)
      setClass(wrap, prefix + "-submenu-wrap-active", false)
      if (!listeningOnClose)
        win.addEventListener("mousedown", listeningOnClose = () => {
          if (!isMenuEvent(wrap)) {
            wrap.classList.remove(prefix + "-submenu-wrap-active")
            win.removeEventListener("mousedown", listeningOnClose!)
            listeningOnClose = null
          }
        })
    })

    function update(state: EditorState) {
      let inner = items.update(state)
      wrap.style.display = inner ? "" : "none"
      return inner
    }
    return {dom: wrap, update}
  }
}

/// Render the given, possibly nested, array of menu elements into a
/// document fragment, placing separators between them (and ensuring no
/// superfluous separators appear when some of the groups turn out to
/// be empty).
export function renderGrouped(view: EditorView, content: readonly (readonly MenuElement[])[]) {
  let result = document.createDocumentFragment()
  let updates: ((state: EditorState) => boolean)[] = [], separators: HTMLElement[] = []
  for (let i = 0; i < content.length; i++) {
    let items = content[i], localUpdates = [], localNodes = []
    for (let j = 0; j < items.length; j++) {
      let {dom, update} = items[j].render(view)
      let span = crel("span", {class: prefix + "item"}, dom)
      result.appendChild(span)
      localNodes.push(span)
      localUpdates.push(update)
    }
    if (localUpdates.length) {
      updates.push(combineUpdates(localUpdates, localNodes))
      if (i < content.length - 1)
        separators.push(result.appendChild(separator()))
    }
  }

  function update(state: EditorState) {
    let something = false, needSep = false
    for (let i = 0; i < updates.length; i++) {
      let hasContent = updates[i](state)
      if (i) separators[i - 1].style.display = needSep && hasContent ? "" : "none"
      needSep = hasContent
      if (hasContent) something = true
    }
    return something
  }
  return {dom: result, update}
}

function separator() {
  return crel("span", {class: prefix + "separator"})
}

/// A set of basic editor-related icons. Contains the properties
/// `join`, `lift`, `selectParentNode`, `undo`, `redo`, `strong`, `em`,
/// `code`, `link`, `bulletList`, `orderedList`, and `blockquote`, each
/// holding an object that can be used as the `icon` option to
/// `MenuItem`.
export const icons: {[name: string]: IconSpec} = {
  join: {
    width: 800, height: 900,
    path: "M0 75h800v125h-800z M0 825h800v-125h-800z M250 400h100v-100h100v100h100v100h-100v100h-100v-100h-100z"
  },
  lift: {
    width: 1024, height: 1024,
    path: "M219 310v329q0 7-5 12t-12 5q-8 0-13-5l-164-164q-5-5-5-13t5-13l164-164q5-5 13-5 7 0 12 5t5 12zM1024 749v109q0 7-5 12t-12 5h-987q-7 0-12-5t-5-12v-109q0-7 5-12t12-5h987q7 0 12 5t5 12zM1024 530v109q0 7-5 12t-12 5h-621q-7 0-12-5t-5-12v-109q0-7 5-12t12-5h621q7 0 12 5t5 12zM1024 310v109q0 7-5 12t-12 5h-621q-7 0-12-5t-5-12v-109q0-7 5-12t12-5h621q7 0 12 5t5 12zM1024 91v109q0 7-5 12t-12 5h-987q-7 0-12-5t-5-12v-109q0-7 5-12t12-5h987q7 0 12 5t5 12z"
  },
  selectParentNode: {text: "\u2b1a", css: "font-weight: bold"},
  undo: {
    width: 1024, height: 1024,
    path: "M761 1024c113-206 132-520-313-509v253l-384-384 384-384v248c534-13 594 472 313 775z"
  },
  redo: {
    width: 1024, height: 1024,
    path: "M576 248v-248l384 384-384 384v-253c-446-10-427 303-313 509-280-303-221-789 313-775z"
  },
  strong: {
    width: 805, height: 1024,
    path: "M317 869q42 18 80 18 214 0 214-191 0-65-23-102-15-25-35-42t-38-26-46-14-48-6-54-1q-41 0-57 5 0 30-0 90t-0 90q0 4-0 38t-0 55 2 47 6 38zM309 442q24 4 62 4 46 0 81-7t62-25 42-51 14-81q0-40-16-70t-45-46-61-24-70-8q-28 0-74 7 0 28 2 86t2 86q0 15-0 45t-0 45q0 26 0 39zM0 950l1-53q8-2 48-9t60-15q4-6 7-15t4-19 3-18 1-21 0-19v-37q0-561-12-585-2-4-12-8t-25-6-28-4-27-2-17-1l-2-47q56-1 194-6t213-5q13 0 39 0t38 0q40 0 78 7t73 24 61 40 42 59 16 78q0 29-9 54t-22 41-36 32-41 25-48 22q88 20 146 76t58 141q0 57-20 102t-53 74-78 48-93 27-100 8q-25 0-75-1t-75-1q-60 0-175 6t-132 6z"
  },
  em: {
    width: 585, height: 1024,
    path: "M0 949l9-48q3-1 46-12t63-21q16-20 23-57 0-4 35-165t65-310 29-169v-14q-13-7-31-10t-39-4-33-3l10-58q18 1 68 3t85 4 68 1q27 0 56-1t69-4 56-3q-2 22-10 50-17 5-58 16t-62 19q-4 10-8 24t-5 22-4 26-3 24q-15 84-50 239t-44 203q-1 5-7 33t-11 51-9 47-3 32l0 10q9 2 105 17-1 25-9 56-6 0-18 0t-18 0q-16 0-49-5t-49-5q-78-1-117-1-29 0-81 5t-69 6z"
  },
  code: {
    width: 896, height: 1024,
    path: "M608 192l-96 96 224 224-224 224 96 96 288-320-288-320zM288 192l-288 320 288 320 96-96-224-224 224-224-96-96z"
  },
  link: {
    width: 951, height: 1024,
    path: "M832 694q0-22-16-38l-118-118q-16-16-38-16-24 0-41 18 1 1 10 10t12 12 8 10 7 14 2 15q0 22-16 38t-38 16q-8 0-15-2t-14-7-10-8-12-12-10-10q-18 17-18 41 0 22 16 38l117 118q15 15 38 15 22 0 38-14l84-83q16-16 16-38zM430 292q0-22-16-38l-117-118q-16-16-38-16-22 0-38 15l-84 83q-16 16-16 38 0 22 16 38l118 118q15 15 38 15 24 0 41-17-1-1-10-10t-12-12-8-10-7-14-2-15q0-22 16-38t38-16q8 0 15 2t14 7 10 8 12 12 10 10q18-17 18-41zM941 694q0 68-48 116l-84 83q-47 47-116 47-69 0-116-48l-117-118q-47-47-47-116 0-70 50-119l-50-50q-49 50-118 50-68 0-116-48l-118-118q-48-48-48-116t48-116l84-83q47-47 116-47 69 0 116 48l117 118q47 47 47 116 0 70-50 119l50 50q49-50 118-50 68 0 116 48l118 118q48 48 48 116z"
  },
  bulletList: {
    width: 768, height: 896,
    path: "M0 512h128v-128h-128v128zM0 256h128v-128h-128v128zM0 768h128v-128h-128v128zM256 512h512v-128h-512v128zM256 256h512v-128h-512v128zM256 768h512v-128h-512v128z"
  },
  orderedList: {
    width: 768, height: 896,
    path: "M320 512h448v-128h-448v128zM320 768h448v-128h-448v128zM320 128v128h448v-128h-448zM79 384h78v-256h-36l-85 23v50l43-2v185zM189 590c0-36-12-78-96-78-33 0-64 6-83 16l1 66c21-10 42-15 67-15s32 11 32 28c0 26-30 58-110 112v50h192v-67l-91 2c49-30 87-66 87-113l1-1z"
  },
  blockquote: {
    width: 640, height: 896,
    path: "M0 448v256h256v-256h-128c0 0 0-128 128-128v-128c0 0-256 0-256 256zM640 320v-128c0 0-256 0-256 256v256h256v-256h-128c0 0 0-128 128-128z"
  }
}

/// Menu item for the `joinUp` command.
export const joinUpItem = new MenuItem({
  title: "Join with above block",
  run: joinUp,
  select: state => joinUp(state),
  icon: icons.join
})

/// Menu item for the `lift` command.
export const liftItem = new MenuItem({
  title: "Lift out of enclosing block",
  run: lift,
  select: state => lift(state),
  icon: icons.lift
})

/// Menu item for the `selectParentNode` command.
export const selectParentNodeItem = new MenuItem({
  title: "Select parent node",
  run: selectParentNode,
  select: state => selectParentNode(state),
  icon: icons.selectParentNode
})

/// Menu item for the `undo` command.
export let undoItem = new MenuItem({
  title: "Undo last change",
  run: undo,
  enable: state => undo(state),
  icon: icons.undo
})

/// Menu item for the `redo` command.
export let redoItem = new MenuItem({
  title: "Redo last undone change",
  run: redo,
  enable: state => redo(state),
  icon: icons.redo
})

/// Build a menu item for wrapping the selection in a given node type.
/// Adds `run` and `select` properties to the ones present in
/// `options`. `options.attrs` may be an object that provides
/// attributes for the wrapping node.
export function wrapItem(nodeType: NodeType, options: Partial<MenuItemSpec> & {attrs?: Attrs | null}) {
  let passedOptions: MenuItemSpec = {
    run(state, dispatch) {
      return wrapIn(nodeType, options.attrs)(state, dispatch)
    },
    select(state) {
      return wrapIn(nodeType, options.attrs)(state)
    }
  }
  for (let prop in options) (passedOptions as any)[prop] = (options as any)[prop]
  return new MenuItem(passedOptions)
}

/// Build a menu item for changing the type of the textblock around the
/// selection to the given type. Provides `run`, `active`, and `select`
/// properties. Others must be given in `options`. `options.attrs` may
/// be an object to provide the attributes for the textblock node.
export function blockTypeItem(nodeType: NodeType, options: Partial<MenuItemSpec> & {attrs?: Attrs | null}) {
  let command = setBlockType(nodeType, options.attrs)
  let passedOptions: MenuItemSpec = {
    run: command,
    enable(state) { return command(state) },
    active(state) {
      let {$from, to, node} = state.selection as NodeSelection
      if (node) return node.hasMarkup(nodeType, options.attrs)
      return to <= $from.end() && $from.parent.hasMarkup(nodeType, options.attrs)
    }
  }
  for (let prop in options) (passedOptions as any)[prop] = (options as any)[prop]
  return new MenuItem(passedOptions)
}

// Work around classList.toggle being broken in IE11
function setClass(dom: HTMLElement, cls: string, on: boolean) {
  if (on) dom.classList.add(cls)
  else dom.classList.remove(cls)
}