'use strict';

import Combokeys from 'combokeys'
import UndoManager from 'undo-manager'
import { getSections, setSelection } from './utils/selection'
import { defineNewLine } from './behaviors/utils'


export default class Editable {
  constructor(elem, { autoIndent = true,
                      autoOpen = true,
                      autoStrip = true,
                      overwrite = true,
                      softTabs = 2,
                      replaceTab = true,
                      pairs = [['(', ')'], ['[', ']'], ['{', '}'], ['"'], ["'"]],
                      oninput = () => {},
                      undoLimit = 0,
                      behavior,
                      store,
                    } = {}) {

    const editable = this
    const handler = behavior(defineNewLine(), softTabs ? ' '.repeat(softTabs) : '\t')

    const undoMgr = new UndoManager()
    undoMgr.setLimit(undoLimit)

    const setDom = (value) => {
      var content = value.prefix + value.selected + value.suffix
      elem.textContent = content
      oninput(content, value)
      setSelection(elem, value.prefix.length, value.prefix.length + value.selected.length)
    }

    const update = (content) => {
      let previous = store()
      undoMgr.add({
        undo : () => { setDom(previous) },
        redo : () => { setDom(content) }
      })
      store(content)
      setDom(content)
    }

    const keys = new Combokeys(elem)
    keys.stopCallback = () => false // work without needing to set combokeys class on elements

    keys.bind('mod+z', () => { undoMgr.undo(); return false })
    keys.bind('shift+mod+z', () => { undoMgr.redo(); return false })

    if (autoIndent) {
      keys.bind('enter', () => getSections(elem, ({ prefix, selected, suffix}) => {
        update(handler.autoIndent(prefix, selected, suffix))
        return false
      }))
    }

    if (autoStrip) {
      keys.bind('backspace', () => getSections(elem, ({ prefix, selected, suffix }, selection) => {
        if (selection.isCollapsed && handler.testAutoStrip(pairs, prefix, selected, suffix)) {
          update(handler.autoStrip(prefix, selected, suffix))
          return false
        }
      }))
    }

    const fnAutoOpen = (opening, closing) => () => getSections(elem, ({ prefix, selected, suffix }) => {
      update(handler.autoOpen(opening, closing, prefix, selected, suffix))
      return false
    })

    const fnOverwrite = (closing) => () => getSections(elem, ({ prefix, selected, suffix }, selection) => {
      if (selection.isCollapsed && handler.testOverwrite(closing, prefix, selected, suffix)) {
        update(handler.overwrite(closing, prefix, selected, suffix))
        return false
      }
    })

    pairs.forEach(([opening, closing]) => {
      if (closing) {
        if (autoOpen)  keys.bind(opening, fnAutoOpen(opening, closing))
        if (overwrite) keys.bind(closing, fnOverwrite(closing))
      } else {
        if (autoOpen && overwrite) {
          keys.bind(opening, () => getSections(elem, ({ prefix, selected, suffix }, selection) => {
            if (selection.isCollapsed && handler.testOverwrite(opening, prefix, selected, suffix))
              update(handler.overwrite(opening, prefix, selected, suffix))
            else
              update(handler.autoOpen(opening, opening, prefix, selected, suffix))
            return false
          }))
        } else {
          if (autoOpen)  keys.bind(opening, fnAutoOpen(opening, opening))
          if (overwrite) keys.bind(opening, fnOverwrite(opening))
        }
      }
    })

    if (replaceTab) {
      keys.bind('tab', () => getSections(elem, ({ prefix, selected, suffix }) => {
        update(handler.tabIndent(prefix, selected, suffix))
        return false
      }))

      keys.bind('shift+tab', () => getSections(elem, ({ prefix, selected, suffix }) => {
        update(handler.tabUnindent(prefix, selected, suffix))
        return false
      }))
    }

    editable.inputListener = elem.addEventListener('input', () => getSections(elem, update))

    oninput(elem.textContent, store())

    // expose for haxxoers
    editable.elem = elem
    editable.handler = handler
    editable.undoMgr = undoMgr
    editable.store = store
    editable.setDom = setDom
    editable.update = update
    editable.keys = keys
  }

  destroy() {
    this.elem.removeEventListener('input', this.inputListener)
    this.keys.detach()
    this.undoMgr.clear()
  }

  focus() {
    this.elem.focus()
  }

  blur() {
    this.elem.blur()
  }
}