//
// read stl
//
// Neil Gershenfeld
// (c) Massachusetts Institute of Technology 2018
//
// This work may be reproduced, modified, distributed, performed, and
// displayed for any purpose, but must acknowledge the mods
// project. Copyright is retained and must be preserved. The work is
// provided as is; no warranty is provided, and users accept all
// liability.
//
// closure
//
(function(){
//
// module globals
//
var mod = {}
//
// name
//
var name = 'read STL'
//
// initialization
//
var init = function() {
   }
//
// inputs
//
var inputs = {
   }
//
// outputs
//
var outputs = {
   mesh:{type:'STL',
      event:function(buffer){
         mods.output(mod,'mesh',buffer)}}
      }
//
// interface
//
var interface = function(div){
   mod.div = div
   //
   // file input control
   //
   var file = document.createElement('input')
      file.setAttribute('type','file')
      file.setAttribute('id',div.id+'file_input')
      file.style.position = 'absolute'
      file.style.left = 0
      file.style.top = 0
      file.style.width = 0
      file.style.height = 0
      file.style.opacity = 0
      file.addEventListener('change',function() {
         stl_read_handler()
         })
      div.appendChild(file)
      mod.file = file
   //
   // canvas
   //
   var canvas = document.createElement('canvas')
      canvas.width = mods.ui.canvas
      canvas.height = mods.ui.canvas
      canvas.style.backgroundColor = 'rgb(255,255,255)'
      div.appendChild(canvas)
      mod.canvas = canvas
   div.appendChild(document.createElement('br'))
   //
   // file select button
   //
   var btn = document.createElement('button')
      btn.style.padding = mods.ui.padding
      btn.style.margin = 1
      btn.appendChild(document.createTextNode('select stl file'))
      btn.addEventListener('click',function(){
         var file = document.getElementById(div.id+'file_input')
         file.value = null
         file.click()
         })
      div.appendChild(btn)
   div.appendChild(document.createElement('br'))
   //
   // info
   //
   var info = document.createElement('div')
      info.setAttribute('id',div.id+'info')
      var text = document.createTextNode('name: ')
         info.appendChild(text)
         mod.namen = text
      info.appendChild(document.createElement('br'))
      var text = document.createTextNode('size: ')
         info.appendChild(text)
         mod.sizen = text
      info.appendChild(document.createElement('br'))
      var text = document.createTextNode('triangles: ')
         info.appendChild(text)
         mod.trianglesn = text
      info.appendChild(document.createElement('br'))
      var text = document.createTextNode('dx: ')
         info.appendChild(text)
         mod.dxn = text
      info.appendChild(document.createElement('br'))
      var text = document.createTextNode('dy: ')
         info.appendChild(text)
         mod.dyn = text
      info.appendChild(document.createElement('br'))
      var text = document.createTextNode('dz: ')
         info.appendChild(text)
         mod.dzn = text
      div.appendChild(info)
   }
//
// local functions
//
// read handler
//
function stl_read_handler(event) {
   var file_reader = new FileReader()
   file_reader.onload = stl_load_handler
   input_file = mod.file.files[0]
   file_name = input_file.name
   mod.namen.nodeValue = 'name: '+file_name
   file_reader.readAsArrayBuffer(input_file)
   }
//
// load handler
//
function stl_load_handler(event) {
   //
   // check for binary STL
   //
   var endian = true
   var view = new DataView(event.target.result)
   var triangles = view.getUint32(80,endian)
   var size = 80+4+triangles*(4*12+2)
   if (size != view.byteLength) {
      mod.sizen.nodeValue = 'error: not binary STL'
      mod.trianglesn.nodeValue = ''
      mod.dxn.nodeValue = ''
      mod.dyn.nodeValue = ''
      mod.dzn.nodeValue = ''
      return
      }
   mod.sizen.nodeValue = 'size: '+size
   mod.trianglesn.nodeValue = 'triangles: '+triangles
   //
   // find limits and draw
   //
   var blob = new Blob(['('+draw_limits_worker.toString()+'())'])
   var url = window.URL.createObjectURL(blob)
   var webworker = new Worker(url)
   webworker.addEventListener('message',function(evt) {
      //
      // worker response
      //
      window.URL.revokeObjectURL(url)
      //
      // size
      //
      mod.dxn.nodeValue = 'dx: '+evt.data.dx.toFixed(3)
      mod.dyn.nodeValue = 'dy: '+evt.data.dy.toFixed(3)
      mod.dzn.nodeValue = 'dz: '+evt.data.dz.toFixed(3)
      //
      // image
      //
      var image = evt.data.image
      var height = mod.canvas.height
      var width = mod.canvas.width
      var buffer = new Uint8ClampedArray(evt.data.image)
      var imgdata = new ImageData(buffer,width,height)
      var ctx = mod.canvas.getContext("2d")
      ctx.putImageData(imgdata,0,0)
      //
      // output
      //
      outputs.mesh.event(evt.data.mesh)
      })
   var ctx = mod.canvas.getContext("2d")
   ctx.clearRect(0,0,mod.canvas.width,mod.canvas.height)
   var img = ctx.getImageData(0,0,mod.canvas.width,mod.canvas.height)
   //
   // call worker
   //
   webworker.postMessage({
      height:mod.canvas.height,width:mod.canvas.width,
      image:img.data.buffer,mesh:event.target.result},
      [img.data.buffer,event.target.result])
   }
function draw_limits_worker() {
   self.addEventListener('message',function(evt) {
      //
      // function to draw line
      //
      function line(x0,y0,x1,y1) {
         var ix0 = Math.floor(xo+xw*(x0-xmin)/dx)
         var iy0 = Math.floor(yo+yh*(ymax-y0)/dy)
         var ix1 = Math.floor(xo+xw*(x1-xmin)/dx)
         var iy1 = Math.floor(yo+yh*(ymax-y1)/dy)
         var row,col
         var idx = ix1-ix0
         var idy = iy1-iy0
         if (Math.abs(idy) > Math.abs(idx)) {
            (idy > 0) ?
               (row0=iy0,col0=ix0,row1=iy1,col1=ix1):
               (row0=iy1,col0=ix1,row1=iy0,col1=ix0)
            for (row = row0; row <= row1; ++row) {
               col = Math.floor(col0+(col1-col0)*(row-row0)/(row1-row0))
               image[row*width*4+col*4+0] = 0
               image[row*width*4+col*4+1] = 0
               image[row*width*4+col*4+2] = 0
               image[row*width*4+col*4+3] = 255
               }
            }
         else if ((Math.abs(idx) >= Math.abs(idy)) && (idx != 0)) {
            (idx > 0) ?
               (row0=iy0,col0=ix0,row1=iy1,col1=ix1):
               (row0=iy1,col0=ix1,row1=iy0,col1=ix0)
            for (col = col0; col <= col1; ++col) {
               row = Math.floor(row0+(row1-row0)*(col-col0)/(col1-col0))
               image[row*width*4+col*4+0] = 0
               image[row*width*4+col*4+1] = 0
               image[row*width*4+col*4+2] = 0
               image[row*width*4+col*4+3] = 255
               }
            }
         else {
            row = iy0
            col = ix0
            image[row*width*4+col*4+0] = 0
            image[row*width*4+col*4+1] = 0
            image[row*width*4+col*4+2] = 0
            image[row*width*4+col*4+3] = 255
            }
         }
      //
      // get variables
      //
      var height = evt.data.height
      var width = evt.data.width
      var endian = true
      var image = new Uint8ClampedArray(evt.data.image)
      var view = new DataView(evt.data.mesh)
      var triangles = view.getUint32(80,endian)
      //
      // find limits
      //
      var offset = 80+4
      var x0,x1,x2,y0,y1,y2,z0,z1,z2
      var xmin = Number.MAX_VALUE
      var xmax = -Number.MAX_VALUE
      var ymin = Number.MAX_VALUE
      var ymax = -Number.MAX_VALUE
      var zmin = Number.MAX_VALUE
      var zmax = -Number.MAX_VALUE
      for (var t = 0; t < triangles; ++t) {
         offset += 3*4
         x0 = view.getFloat32(offset,endian)
         offset += 4
         if (x0 > xmax) xmax = x0
         if (x0 < xmin) xmin = x0
         y0 = view.getFloat32(offset,endian)
         offset += 4
         if (y0 > ymax) ymax = y0
         if (y0 < ymin) ymin = y0
         z0 = view.getFloat32(offset,endian)
         offset += 4
         if (z0 > zmax) zmax = z0
         if (z0 < zmin) zmin = z0
         x1 = view.getFloat32(offset,endian)
         offset += 4
         if (x1 > xmax) xmax = x1
         if (x1 < xmin) xmin = x1
         y1 = view.getFloat32(offset,endian)
         offset += 4
         if (y1 > ymax) ymax = y1
         if (y1 < ymin) ymin = y1
         z1 = view.getFloat32(offset,endian)
         offset += 4
         if (z1 > zmax) zmax = z1
         if (z1 < zmin) zmin = z1
         x2 = view.getFloat32(offset,endian)
         offset += 4
         if (x2 > xmax) xmax = x2
         if (x2 < xmin) xmin = x2
         y2 = view.getFloat32(offset,endian)
         offset += 4
         if (y2 > ymax) ymax = y2
         if (y2 < ymin) ymin = y2
         z2 = view.getFloat32(offset,endian)
         offset += 4
         if (z2 > zmax) zmax = z2
         if (z2 < zmin) zmin = z2
         offset += 2
         }
      var dx = xmax-xmin
      var dy = ymax-ymin
      var dz = zmax-zmin
      //
      // draw mesh
      //
      if (dx > dy) {
         var xo = 0
         var yo = height*.5*(1-dy/dx)
         var xw = width-1
         var yh = (width-1)*dy/dx
         }
      else {
         var xo = width*.5*(1-dx/dy)
         var yo = 0
         var xw = (height-1)*dx/dy
         var yh = height-1
         }
      offset = 80+4
      for (var t = 0; t < triangles; ++t) {
         offset += 3*4
         x0 = view.getFloat32(offset,endian)
         offset += 4
         y0 = view.getFloat32(offset,endian)
         offset += 4
         z0 = view.getFloat32(offset,endian)
         offset += 4
         x1 = view.getFloat32(offset,endian)
         offset += 4
         y1 = view.getFloat32(offset,endian)
         offset += 4
         z1 = view.getFloat32(offset,endian)
         offset += 4
         x2 = view.getFloat32(offset,endian)
         offset += 4
         y2 = view.getFloat32(offset,endian)
         offset += 4
         z2 = view.getFloat32(offset,endian)
         offset += 4
         offset += 2
         line(x0,y0,x1,y1)
         line(x1,y1,x2,y2)
         line(x2,y2,x0,y0)
         }
      //
      // return results and close
      //
      self.postMessage({
         dx:dx,dy:dy,dz:dz,
         image:evt.data.image,mesh:evt.data.mesh},[evt.data.image,evt.data.mesh])
      self.close()
      })
   }
//
// return values
//
return ({
   mod:mod,
   name:name,
   init:init,
   inputs:inputs,
   outputs:outputs,
   interface:interface
   })
}())