--- A generic element every element must inherit from.
--- @classmod element
--- @copyright Paul Liverman III (2016)
--- @license The MIT License (MIT)

local pop

import graphics from love
import floor, max from math
import inheritsFromElement from require "#{(...)\sub 1, -19}/util"

class element
  load: (pop_lib) ->
    pop = pop_lib

  --- Constructor expects nothing, or a data table describing it.
  --- @tparam ?Element|false parent The parent element.
  --- @tparam table data[opt] The data (state) for this element.
  --- @treturn element self
  new: (@parent, @data={}) =>
    if type(@data) != "table"
      @data = {}

    @data.parent = false unless @data.parent
    @data.child = {} unless @data.child
    @data.type = "element" unless @data.type

    @data.update = true if @data.update == nil
    @data.draw = true if @data.draw == nil
    @data.hoverable = true if @data.hoverable == nil
    -- @data.static = false if @data.static == nil

    unless @data.x
      if @parent
        @data.x = @parent.data.x
      else
        @data.x = 0
    unless @data.y
      if @parent
        @data.y = @parent.data.y
      else
        @data.y = 0
    @data.w = 0 unless @data.w
    @data.h = 0 unless @data.h

    @data.size = 0 unless @data.size
    @data.verticalSize = 0 unless @data.verticalSize
    @data.horizontalSize = 0 unless @data.horizontalSize

    @data.align = true if (@data.align == nil) and @parent
    @data.verticalAlign = "top" unless @data.verticalAlign
    @data.horizontalAlign = "left" unless @data.horizontalAlign

    @data.margin = 0 unless @data.margin
    @data.horizontalMargin = 0 unless @data.horizontalMargin
    @data.verticalMargin = 0 unless @data.verticalMargin

    @data.padding = 0 unless @data.padding
    @data.horizontalPadding = 0 unless @data.horizontalPadding
    @data.verticalPadding = 0 unless @data.verticalPadding

    @child = {}

    unless @__class.align -- this is so elements setting up their own alignment (such as window) won't break by alignment being called prematurely
      if @data.size != 0 or @data.verticalSize != 0 or @data.horizontalSize != 0
        @setSize @parent.data.w * (@data.size + @data.verticalSize), @parent.data.h * (@data.size + @data.horizontalSize)
      elseif @data.align
        @align!

  --- @todo doc me
  align: (horizontal, vertical, toPixel=true) =>
    unless @data.align return @

    @data.horizontalAlign = horizontal if horizontal
    @data.verticalAlign = vertical if vertical

    @data.x = @parent.data.x
    @data.y = @parent.data.y

    switch @data.horizontalAlign
      when "left"
        @data.x += max(@parent.data.padding + @parent.data.horizontalPadding, @data.margin + @data.horizontalMargin)
      when "center"
        @data.x += (@parent.data.w - @data.w) / 2
      when "right"
        @data.x += @parent.data.w - @data.w - max(@parent.data.padding + @parent.data.horizontalPadding, @data.margin + @data.horizontalMargin)
      else
        @data.x += @parent.data.w * @data.horizontalAlign
        if @data.horizontalAlign < 0
          @data.x += @parent.data.w

    switch @data.verticalAlign
      when "top"
        @data.y += @parent.data.padding + @data.margin + @data.verticalMargin
      when "center"
        @data.y += (@parent.data.h - @data.h) / 2
      when "bottom"
        @data.y += @parent.data.h - @data.h - max(@parent.data.padding + @parent.data.verticalPadding, @data.margin + @data.verticalMargin)
      else
        @data.y += @parent.data.h * @data.verticalAlign
        if @data.verticalAlign < 0
          @data.y += @parent.data.h

    if toPixel
      @data.x = floor @data.x
      @data.y = floor @data.y

    return @

  --- @todo document this
  setPosition: (x, y, toPixel=true) =>
    dx, dy = @data.x, @data.y

    if x
      @data.x = x
      switch @data.horizontalAlign
        when "center"
          @data.x -= @data.w / 2
        when "right"
          @data.x -= @data.w

    if y
      @data.y = y
      switch @data.verticalAlign
        when "center"
          @data.y -= @data.h / 2
        when "bottom"
          @data.y -= @data.h

    if toPixel
      @data.x = floor @data.x
      @data.y = floor @data.y

    -- new minus old is difference that children need to be moved
    dx = @data.x - dx
    dy = @data.y - dy
    for child in *@child
      child\move dx, dy

    return @

  --- @todo doc me
  getPosition: =>
    x, y = @data.x, @data.y

    switch @data.horizontalAlign
      when "center"
        x += @data.w / 2
      when "right"
        y += @data.w

    switch @data.verticalAlign
      when "center"
        y += @data.h / 2
      when "bottom"
        y += @data.h

    return x, y

  --- Sets an element's width/height. Fixes alignment if needed.
  --- @tparam integer w[opt] Width.
  --- @tparam integer h[opt] Height.
  --- @treturn element self
  setSize: (w, h) =>
    if w
      @data.w = w
    if h
      @data.h = h

    @align!

    return @

  --- Returns an element's width and height.
  --- @treturn integer Width.
  --- @treturn integer Height.
  getSize: =>
    return @data.w, @data.h

  --- Sets an element's width.
  --- @tparam integer w Width.
  --- @treturn element self
  setWidth: (w) =>
    @data.w = w
    @align!
    return @

  --- Returns an element's width.
  --- @treturn integer Width.
  getWidth: =>
    return @data.w

  --- Sets an element's height.
  --- @tparam integer h Height.
  --- @treturn element self
  setHeight: (h) =>
    @data.h = h
    @align!
    return @

  --- Returns an element's height.
  --- @treturn integer Height.
  getHeight: =>
    return @data.h

  --- @todo doc me
  adjustSize: (w, h) =>
    W, H = @getSize!

    if w
      W += w
    if h
      H += h

    @setSize W, H

    return @

  --- Moves an element by specified x/y.
  --- @treturn element self
  move: (x=0, y=0) =>
    --if @data.static return @

    @data.x += x
    @data.y += y

    for child in *@child
      child\move x, y

    return @

  setPadding: (padding) =>
    @data.padding = padding
    @align!
    return @

  getPadding: =>
    return @data.padding

  setMargin: (margin) =>
    @data.margin = margin
    @align!
    return @

  getMargin: =>
    return @data.margin

  indexOf: (element) =>
    for i = 1, #@child
      if @child[i] == element
          return i

  dataIndexOf: (data) =>
    for i = 1, #@data.child
      if @data.child[i] == data
        return i

  add: (element) =>
    unless inheritsFromElement element
      for e in *element
        @add e
        return @

    element.parent\remove(element)

    table.insert @child, element
    table.insert @data.child, element.data

    return @

  remove: (element) =>
    unless inheritsFromElement element
      for e in *element
        @remove e
        return @

    index = @indexOf element
    dataIndex = @dataIndexOf element.data

    table.remove @child, index
    table.remove @data.child, dataIndex

    return @

  --- Deletes references to this element and then deletes it.
  delete: =>
    -- does not work for desired issue, element is still referenced and set as focused after this would be called
    -- however, it is probably a good idea for anything being deleted to make sure it isn't focused
    if @ == pop.hovered
      pop.hovered = false
      pop.log "#{@} (#{@type}) unfocused (deleted)"

    for i=#@child, 1, -1
      @child[i]\delete!

    if @parent
      for i=1, #@parent.child
        if @parent.child[i] == @
          table.remove @parent.child, i
          break

    if @parent
      for i=1, #@parent.data.child
        if @parent.data.child[i] == @data
          table.remove @parent.data.child, i
          break

    @parent = nil
    @data.parent = nil -- should be for all @ -> nil MAYBE
    @ = nil
    -- DO NOT DELETE @data though, it could still be in use