const {inchMM, ptMM, pcMM, svgColors} = require('./constants')

// Calculate the CAG length/size from the given SVG value (float)
const svg2cagX = function (v, svgUnitsPmm) {
  return (v / svgUnitsPmm[0])
}

const svg2cagY = function (v, svgUnitsPmm) {
  return 0 - (v / svgUnitsPmm[1])
}

// Calculate the CAG length/size from the given CSS value (string)
const cagLengthX = function (css, svgUnitsPmm, svgUnitsX) {
  if (css.indexOf('%') < 0) {
    return css2cag(css, svgUnitsPmm[0])
  }
  // calculate the units as a percentage of the width
  var v = parseFloat(css) // number part
  if (isNaN(v)) { return 0.0 }
  if (v === 0) return v
  v = (v / 100) * svgUnitsX
  // convert the units to mm
  v = v / svgUnitsPmm[0]
  // return v;
  return Math.round(v / -100000) * -100000
}

const cagLengthY = function (css, svgUnitsPmm, svgUnitsY) {
  if (css.indexOf('%') < 0) {
    return css2cag(css, svgUnitsPmm[1])
  }
  // calculate the units as a percentage of the width
  var v = parseFloat(css) // number part
  if (isNaN(v)) { return 0.0 }
  if (v === 0) return v
  v = (v / 100) * svgUnitsY
  // convert the units to mm
  v = v / svgUnitsPmm[1]
  // return v;
  return Math.round(v / -100000) * -100000
}

const cagLengthP = function (css, svgUnitsPmm, svgUnitsV) {
  if (css.indexOf('%') < 0) {
    return css2cag(css, svgUnitsPmm[1])
  }
  // calculate the units as a percentage of the viewport
  var v = parseFloat(css) // number part
  if (isNaN(v)) { return 0.0 }
  if (v === 0) return v
  v = (v / 100) * svgUnitsV
  // convert the units to mm
  v = v / svgUnitsPmm[0] // FIXME should this use X units?
  return v
}

const css2cag = function (css, unit) {
// console.log('css2cag('+css+','+unit+')');
  var v = parseFloat(css) // number part
  if (isNaN(v)) { return 0.0 }
  if (v === 0) return v
  if (css.search(/EM/i) > 0) { // FIXME self assignment , useless ?
    // v = v // font size
  } else
  if (css.search(/EX/i) > 0) { // FIXME self assignment , useless ?
    // v = v // x-height of font
  } else
  if (css.search(/MM/i) > 0) { // FIXME self assignment , useless ?
    // v = v // absolute millimeters
  } else
  if (css.search(/CM/i) > 0) {
    v = (v * 10) // absolute centimeters > millimeters
  } else
  if (css.search(/IN/i) > 0) {
    v = (v / inchMM) // absolute inches > millimeters
  } else
  if (css.search(/PT/i) > 0) {
    v = (v / ptMM) // absolute points > millimeters
  } else
  if (css.search(/PC/i) > 0) {
    v = (v / pcMM) // absolute picas > millimeters
  } else {
    v = (v / unit) // absolute pixels(units) > millimeters
  }
  // console.log('v ('+v+')');
  return v
}

// convert the SVG color specification to CAG RGB
const cagColor = function (value) {
  // var rgb = [0,0,0]; // default is black
  var rgb = null
  value = value.toLowerCase()
  if (value in svgColors) {
    rgb = svgColors[value]
    rgb = [rgb[0] / 255, rgb[1] / 255, rgb[2] / 255] // converted to 0.0-1.0 values
  } else {
    if (value[0] === '#') {
      if (value.length === 4) {
      // short HEX specification
        value = '#' + value[1] + value[1] + value[2] + value[2] + value[3] + value[3]
      }
      if (value.length === 7) {
      // HEX specification
        rgb = [ parseInt('0x' + value.slice(1, 3)) / 255,
          parseInt('0x' + value.slice(3, 5)) / 255,
          parseInt('0x' + value.slice(5, 7)) / 255 ]
      }
    } else {
      var pat = /rgb\(.+,.+,.+\)/
      var s = pat.exec(value)
      if (s !== null) {
      // RGB specification
        s = s[0]
        s = s.slice(s.indexOf('(') + 1, s.indexOf(')'))
        rgb = s.split(',')
        if (s.indexOf('%') > 0) {
        // rgb(#%,#%,#%)
          rgb = [parseInt(rgb[0]), parseInt(rgb[1]), parseInt(rgb[2])]
          rgb = [rgb[0] / 100, rgb[1] / 100, rgb[2] / 100] // converted to 0.0-1.0 values
        } else {
        // rgb(#,#,#)
          rgb = [parseInt(rgb[0]), parseInt(rgb[1]), parseInt(rgb[2])]
          rgb = [rgb[0] / 255, rgb[1] / 255, rgb[2] / 255] // converted to 0.0-1.0 values
        }
      }
    }
  }
  return rgb
}

const cssStyle = function (element, name) {
  if ('STYLE' in element) {
    var list = element.STYLE
    var pat = name + '\\s*:\\s*\\S+;'
    var exp = new RegExp(pat, 'i')
    var v = exp.exec(list)
    if (v !== null) {
      v = v[0]
      var i = v.length
      while (v[i] !== ' ') i--
      v = v.slice(i + 1, v.length - 1)
      return v
    }
  }
  return null
}

const reflect = function (x, y, px, py) {
  var ox = x - px
  var oy = y - py
  if (x === px && y === px) return [x, y]
  if (x === px) return [x, py + (-oy)]
  if (y === py) return [px + (-ox), y]
  return [px + (-ox), py + (-oy)]
}

// Return the value for the given attribute from the group hiearchy
const groupValue = function (svgGroups, name) {
  var i = svgGroups.length
  while (i > 0) {
    const g = svgGroups[i - 1]
    if (name in g) {
      return g[name]
    }
    i--
  }
  return null
}

module.exports = {
  svg2cagX,
  svg2cagY,
  cagLengthX,
  cagLengthY,
  cagLengthP,
  css2cag,
  cagColor,
  cssStyle,
  reflect,
  groupValue
}