// Copyright (c) 2013 Adobe Systems Incorporated. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
import eve from './eve.js'
import { Snap } from './svg.js'

Snap.plugin(function (Snap, Element, Paper, glob) {
  var elproto = Element.prototype,
    pproto = Paper.prototype,
    rgurl = /^\s*url\((.+)\)/,
    Str = String,
    $ = Snap._.$
  Snap.filter = {}
  /*\
     * Paper.filter
     [ method ]
     **
     * Creates a `<filter>` element
     **
     - filstr (string) SVG fragment of filter provided as a string
     = (object) @Element
     * Note: It is recommended to use filters embedded into the page inside an empty SVG element.
     > Usage
     | var f = paper.filter('<feGaussianBlur stdDeviation="2"/>'),
     |     c = paper.circle(10, 10, 10).attr({
     |         filter: f
     |     });
    \*/
  pproto.filter = function (filstr) {
    var paper = this
    if (paper.type != 'svg') {
      paper = paper.paper
    }
    var f = Snap.parse(Str(filstr)),
      id = Snap._.id(),
      width = paper.node.offsetWidth,
      height = paper.node.offsetHeight,
      filter = $('filter')
    $(filter, {
      id: id,
      filterUnits: 'userSpaceOnUse'
    })
    filter.appendChild(f.node)
    paper.defs.appendChild(filter)
    return new Element(filter)
  }

  eve.on('snap.util.getattr.filter', function () {
    eve.stop()
    var p = $(this.node, 'filter')
    if (p) {
      var match = Str(p).match(rgurl)
      return match && Snap.select(match[1])
    }
  })
  eve.on('snap.util.attr.filter', function (value) {
    if (value instanceof Element && value.type == 'filter') {
      eve.stop()
      var id = value.node.id
      if (!id) {
        $(value.node, { id: value.id })
        id = value.id
      }
      $(this.node, {
        filter: Snap.url(id)
      })
    }
    if (!value || value == 'none') {
      eve.stop()
      this.node.removeAttribute('filter')
    }
  })
  /*\
     * Snap.filter.blur
     [ method ]
     **
     * Returns an SVG markup string for the blur filter
     **
     - x (number) amount of horizontal blur, in pixels
     - y (number) #optional amount of vertical blur, in pixels
     = (string) filter representation
     > Usage
     | var f = paper.filter(Snap.filter.blur(5, 10)),
     |     c = paper.circle(10, 10, 10).attr({
     |         filter: f
     |     });
    \*/
  Snap.filter.blur = function (x, y) {
    if (x == null) {
      x = 2
    }
    var def = y == null ? x : [x, y]
    return Snap.format('<feGaussianBlur stdDeviation="{def}"/>', {
      def: def
    })
  }
  Snap.filter.blur.toString = function () {
    return this()
  }
  /*\
     * Snap.filter.shadow
     [ method ]
     **
     * Returns an SVG markup string for the shadow filter
     **
     - dx (number) #optional horizontal shift of the shadow, in pixels
     - dy (number) #optional vertical shift of the shadow, in pixels
     - blur (number) #optional amount of blur
     - color (string) #optional color of the shadow
     - opacity (number) #optional `0..1` opacity of the shadow
     * or
     - dx (number) #optional horizontal shift of the shadow, in pixels
     - dy (number) #optional vertical shift of the shadow, in pixels
     - color (string) #optional color of the shadow
     - opacity (number) #optional `0..1` opacity of the shadow
     * which makes blur default to `4`. Or
     - dx (number) #optional horizontal shift of the shadow, in pixels
     - dy (number) #optional vertical shift of the shadow, in pixels
     - opacity (number) #optional `0..1` opacity of the shadow
     = (string) filter representation
     > Usage
     | var f = paper.filter(Snap.filter.shadow(0, 2, .3)),
     |     c = paper.circle(10, 10, 10).attr({
     |         filter: f
     |     });
    \*/
  Snap.filter.shadow = function (dx, dy, blur, color, opacity) {
    if (opacity == null) {
      if (color == null) {
        opacity = blur
        blur = 4
        color = '#000'
      } else {
        opacity = color
        color = blur
        blur = 4
      }
    }
    if (blur == null) {
      blur = 4
    }
    if (opacity == null) {
      opacity = 1
    }
    if (dx == null) {
      dx = 0
      dy = 2
    }
    if (dy == null) {
      dy = dx
    }
    color = Snap.color(color)
    return Snap.format(
      '<feGaussianBlur in="SourceAlpha" stdDeviation="{blur}"/><feOffset dx="{dx}" dy="{dy}" result="offsetblur"/><feFlood flood-color="{color}"/><feComposite in2="offsetblur" operator="in"/><feComponentTransfer><feFuncA type="linear" slope="{opacity}"/></feComponentTransfer><feMerge><feMergeNode/><feMergeNode in="SourceGraphic"/></feMerge>',
      {
        color: color,
        dx: dx,
        dy: dy,
        blur: blur,
        opacity: opacity
      }
    )
  }
  Snap.filter.shadow.toString = function () {
    return this()
  }
  /*\
     * Snap.filter.grayscale
     [ method ]
     **
     * Returns an SVG markup string for the grayscale filter
     **
     - amount (number) amount of filter (`0..1`)
     = (string) filter representation
    \*/
  Snap.filter.grayscale = function (amount) {
    if (amount == null) {
      amount = 1
    }
    return Snap.format(
      '<feColorMatrix type="matrix" values="{a} {b} {c} 0 0 {d} {e} {f} 0 0 {g} {b} {h} 0 0 0 0 0 1 0"/>',
      {
        a: 0.2126 + 0.7874 * (1 - amount),
        b: 0.7152 - 0.7152 * (1 - amount),
        c: 0.0722 - 0.0722 * (1 - amount),
        d: 0.2126 - 0.2126 * (1 - amount),
        e: 0.7152 + 0.2848 * (1 - amount),
        f: 0.0722 - 0.0722 * (1 - amount),
        g: 0.2126 - 0.2126 * (1 - amount),
        h: 0.0722 + 0.9278 * (1 - amount)
      }
    )
  }
  Snap.filter.grayscale.toString = function () {
    return this()
  }
  /*\
     * Snap.filter.sepia
     [ method ]
     **
     * Returns an SVG markup string for the sepia filter
     **
     - amount (number) amount of filter (`0..1`)
     = (string) filter representation
    \*/
  Snap.filter.sepia = function (amount) {
    if (amount == null) {
      amount = 1
    }
    return Snap.format(
      '<feColorMatrix type="matrix" values="{a} {b} {c} 0 0 {d} {e} {f} 0 0 {g} {h} {i} 0 0 0 0 0 1 0"/>',
      {
        a: 0.393 + 0.607 * (1 - amount),
        b: 0.769 - 0.769 * (1 - amount),
        c: 0.189 - 0.189 * (1 - amount),
        d: 0.349 - 0.349 * (1 - amount),
        e: 0.686 + 0.314 * (1 - amount),
        f: 0.168 - 0.168 * (1 - amount),
        g: 0.272 - 0.272 * (1 - amount),
        h: 0.534 - 0.534 * (1 - amount),
        i: 0.131 + 0.869 * (1 - amount)
      }
    )
  }
  Snap.filter.sepia.toString = function () {
    return this()
  }
  /*\
     * Snap.filter.saturate
     [ method ]
     **
     * Returns an SVG markup string for the saturate filter
     **
     - amount (number) amount of filter (`0..1`)
     = (string) filter representation
    \*/
  Snap.filter.saturate = function (amount) {
    if (amount == null) {
      amount = 1
    }
    return Snap.format('<feColorMatrix type="saturate" values="{amount}"/>', {
      amount: 1 - amount
    })
  }
  Snap.filter.saturate.toString = function () {
    return this()
  }
  /*\
     * Snap.filter.hueRotate
     [ method ]
     **
     * Returns an SVG markup string for the hue-rotate filter
     **
     - angle (number) angle of rotation
     = (string) filter representation
    \*/
  Snap.filter.hueRotate = function (angle) {
    angle = angle || 0
    return Snap.format('<feColorMatrix type="hueRotate" values="{angle}"/>', {
      angle: angle
    })
  }
  Snap.filter.hueRotate.toString = function () {
    return this()
  }
  /*\
     * Snap.filter.invert
     [ method ]
     **
     * Returns an SVG markup string for the invert filter
     **
     - amount (number) amount of filter (`0..1`)
     = (string) filter representation
    \*/
  Snap.filter.invert = function (amount) {
    if (amount == null) {
      amount = 1
    }
    //        <feColorMatrix type="matrix" values="-1 0 0 0 1  0 -1 0 0 1  0 0 -1 0 1  0 0 0 1 0" color-interpolation-filters="sRGB"/>
    return Snap.format(
      '<feComponentTransfer><feFuncR type="table" tableValues="{amount} {amount2}"/><feFuncG type="table" tableValues="{amount} {amount2}"/><feFuncB type="table" tableValues="{amount} {amount2}"/></feComponentTransfer>',
      {
        amount: amount,
        amount2: 1 - amount
      }
    )
  }
  Snap.filter.invert.toString = function () {
    return this()
  }
  /*\
     * Snap.filter.brightness
     [ method ]
     **
     * Returns an SVG markup string for the brightness filter
     **
     - amount (number) amount of filter (`0..1`)
     = (string) filter representation
    \*/
  Snap.filter.brightness = function (amount) {
    if (amount == null) {
      amount = 1
    }
    return Snap.format(
      '<feComponentTransfer><feFuncR type="linear" slope="{amount}"/><feFuncG type="linear" slope="{amount}"/><feFuncB type="linear" slope="{amount}"/></feComponentTransfer>',
      {
        amount: amount
      }
    )
  }
  Snap.filter.brightness.toString = function () {
    return this()
  }
  /*\
     * Snap.filter.contrast
     [ method ]
     **
     * Returns an SVG markup string for the contrast filter
     **
     - amount (number) amount of filter (`0..1`)
     = (string) filter representation
    \*/
  Snap.filter.contrast = function (amount) {
    if (amount == null) {
      amount = 1
    }
    return Snap.format(
      '<feComponentTransfer><feFuncR type="linear" slope="{amount}" intercept="{amount2}"/><feFuncG type="linear" slope="{amount}" intercept="{amount2}"/><feFuncB type="linear" slope="{amount}" intercept="{amount2}"/></feComponentTransfer>',
      {
        amount: amount,
        amount2: 0.5 - amount / 2
      }
    )
  }
  Snap.filter.contrast.toString = function () {
    return this()
  }
})