'use strict'

var ndarray = require('ndarray')
var ops     = require('ndarray-ops')
var pool    = require('typedarray-pool')

module.exports = createTexture2D

var linearTypes = null
var filterTypes = null
var wrapTypes   = null

function lazyInitLinearTypes(gl) {
  linearTypes = [
    gl.LINEAR,
    gl.NEAREST_MIPMAP_LINEAR,
    gl.LINEAR_MIPMAP_NEAREST,
    gl.LINEAR_MIPMAP_NEAREST
  ]
  filterTypes = [
    gl.NEAREST,
    gl.LINEAR,
    gl.NEAREST_MIPMAP_NEAREST,
    gl.NEAREST_MIPMAP_LINEAR,
    gl.LINEAR_MIPMAP_NEAREST,
    gl.LINEAR_MIPMAP_LINEAR
  ]
  wrapTypes = [
    gl.REPEAT,
    gl.CLAMP_TO_EDGE,
    gl.MIRRORED_REPEAT
  ]
}

function acceptTextureDOM (obj) {
  return (
    ('undefined' != typeof HTMLCanvasElement && obj instanceof HTMLCanvasElement) ||
    ('undefined' != typeof HTMLImageElement && obj instanceof HTMLImageElement) ||
    ('undefined' != typeof HTMLVideoElement && obj instanceof HTMLVideoElement) ||
    ('undefined' != typeof ImageData && obj instanceof ImageData))
}

var convertFloatToUint8 = function(out, inp) {
  ops.muls(out, inp, 255.0)
}

function reshapeTexture(tex, w, h) {
  var gl = tex.gl
  var maxSize = gl.getParameter(gl.MAX_TEXTURE_SIZE)
  if(w < 0 || w > maxSize || h < 0 || h > maxSize) {
    throw new Error('gl-texture2d: Invalid texture size')
  }
  tex._shape = [w, h]
  tex.bind()
  gl.texImage2D(gl.TEXTURE_2D, 0, tex.format, w, h, 0, tex.format, tex.type, null)
  tex._mipLevels = [0]
  return tex
}

function Texture2D(gl, handle, width, height, format, type) {
  this.gl = gl
  this.handle = handle
  this.format = format
  this.type = type
  this._shape = [width, height]
  this._mipLevels = [0]
  this._magFilter = gl.NEAREST
  this._minFilter = gl.NEAREST
  this._wrapS = gl.CLAMP_TO_EDGE
  this._wrapT = gl.CLAMP_TO_EDGE
  this._anisoSamples = 1

  var parent = this
  var wrapVector = [this._wrapS, this._wrapT]
  Object.defineProperties(wrapVector, [
    {
      get: function() {
        return parent._wrapS
      },
      set: function(v) {
        return parent.wrapS = v
      }
    },
    {
      get: function() {
        return parent._wrapT
      },
      set: function(v) {
        return parent.wrapT = v
      }
    }
  ])
  this._wrapVector = wrapVector

  var shapeVector = [this._shape[0], this._shape[1]]
  Object.defineProperties(shapeVector, [
    {
      get: function() {
        return parent._shape[0]
      },
      set: function(v) {
        return parent.width = v
      }
    },
    {
      get: function() {
        return parent._shape[1]
      },
      set: function(v) {
        return parent.height = v
      }
    }
  ])
  this._shapeVector = shapeVector
}

var proto = Texture2D.prototype

Object.defineProperties(proto, {
  minFilter: {
    get: function() {
      return this._minFilter
    },
    set: function(v) {
      this.bind()
      var gl = this.gl
      if(this.type === gl.FLOAT && linearTypes.indexOf(v) >= 0) {
        if(!gl.getExtension('OES_texture_float_linear')) {
          v = gl.NEAREST
        }
      }
      if(filterTypes.indexOf(v) < 0) {
        throw new Error('gl-texture2d: Unknown filter mode ' + v)
      }
      gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, v)
      return this._minFilter = v
    }
  },
  magFilter: {
    get: function() {
      return this._magFilter
    },
    set: function(v) {
      this.bind()
      var gl = this.gl
      if(this.type === gl.FLOAT && linearTypes.indexOf(v) >= 0) {
        if(!gl.getExtension('OES_texture_float_linear')) {
          v = gl.NEAREST
        }
      }
      if(filterTypes.indexOf(v) < 0) {
        throw new Error('gl-texture2d: Unknown filter mode ' + v)
      }
      gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, v)
      return this._magFilter = v
    }
  },
  mipSamples: {
    get: function() {
      return this._anisoSamples
    },
    set: function(i) {
      var psamples = this._anisoSamples
      this._anisoSamples = Math.max(i, 1)|0
      if(psamples !== this._anisoSamples) {
        var ext = this.gl.getExtension('EXT_texture_filter_anisotropic')
        if(ext) {
          this.gl.texParameterf(this.gl.TEXTURE_2D, ext.TEXTURE_MAX_ANISOTROPY_EXT, this._anisoSamples)
        }
      }
      return this._anisoSamples
    }
  },
  wrapS: {
    get: function() {
      return this._wrapS
    },
    set: function(v) {
      this.bind()
      if(wrapTypes.indexOf(v) < 0) {
        throw new Error('gl-texture2d: Unknown wrap mode ' + v)
      }
      this.gl.texParameteri(this.gl.TEXTURE_2D, this.gl.TEXTURE_WRAP_S, v)
      return this._wrapS = v
    }
  },
  wrapT: {
    get: function() {
      return this._wrapT
    },
    set: function(v) {
      this.bind()
      if(wrapTypes.indexOf(v) < 0) {
        throw new Error('gl-texture2d: Unknown wrap mode ' + v)
      }
      this.gl.texParameteri(this.gl.TEXTURE_2D, this.gl.TEXTURE_WRAP_T, v)
      return this._wrapT = v
    }
  },
  wrap: {
    get: function() {
      return this._wrapVector
    },
    set: function(v) {
      if(!Array.isArray(v)) {
        v = [v,v]
      }
      if(v.length !== 2) {
        throw new Error('gl-texture2d: Must specify wrap mode for rows and columns')
      }
      for(var i=0; i<2; ++i) {
        if(wrapTypes.indexOf(v[i]) < 0) {
          throw new Error('gl-texture2d: Unknown wrap mode ' + v)
        }
      }
      this._wrapS = v[0]
      this._wrapT = v[1]

      var gl = this.gl
      this.bind()
      gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, this._wrapS)
      gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, this._wrapT)

      return v
    }
  },
  shape: {
    get: function() {
      return this._shapeVector
    },
    set: function(x) {
      if(!Array.isArray(x)) {
        x = [x|0,x|0]
      } else {
        if(x.length !== 2) {
          throw new Error('gl-texture2d: Invalid texture shape')
        }
      }
      reshapeTexture(this, x[0]|0, x[1]|0)
      return [x[0]|0, x[1]|0]
    }
  },
  width: {
    get: function() {
      return this._shape[0]
    },
    set: function(w) {
      w = w|0
      reshapeTexture(this, w, this._shape[1])
      return w
    }
  },
  height: {
    get: function() {
      return this._shape[1]
    },
    set: function(h) {
      h = h|0
      reshapeTexture(this, this._shape[0], h)
      return h
    }
  }
})

proto.bind = function(unit) {
  var gl = this.gl
  if(unit !== undefined) {
    gl.activeTexture(gl.TEXTURE0 + (unit|0))
  }
  gl.bindTexture(gl.TEXTURE_2D, this.handle)
  if(unit !== undefined) {
    return (unit|0)
  }
  return gl.getParameter(gl.ACTIVE_TEXTURE) - gl.TEXTURE0
}

proto.dispose = function() {
  this.gl.deleteTexture(this.handle)
}

proto.generateMipmap = function() {
  this.bind()
  this.gl.generateMipmap(this.gl.TEXTURE_2D)

  //Update mip levels
  var l = Math.min(this._shape[0], this._shape[1])
  for(var i=0; l>0; ++i, l>>>=1) {
    if(this._mipLevels.indexOf(i) < 0) {
      this._mipLevels.push(i)
    }
  }
}

proto.setPixels = function(data, x_off, y_off, mip_level) {
  var gl = this.gl
  this.bind()
  if(Array.isArray(x_off)) {
    mip_level = y_off
    y_off = x_off[1]|0
    x_off = x_off[0]|0
  } else {
    x_off = x_off || 0
    y_off = y_off || 0
  }
  mip_level = mip_level || 0
  var directData = acceptTextureDOM(data) ? data : data.raw
  if(directData) {
    var needsMip = this._mipLevels.indexOf(mip_level) < 0
    if(needsMip) {
      gl.texImage2D(gl.TEXTURE_2D, 0, this.format, this.format, this.type, directData)
      this._mipLevels.push(mip_level)
    } else {
      gl.texSubImage2D(gl.TEXTURE_2D, mip_level, x_off, y_off, this.format, this.type, directData)
    }
  } else if(data.shape && data.stride && data.data) {
    if(data.shape.length < 2 ||
       x_off + data.shape[1] > this._shape[1]>>>mip_level ||
       y_off + data.shape[0] > this._shape[0]>>>mip_level ||
       x_off < 0 ||
       y_off < 0) {
      throw new Error('gl-texture2d: Texture dimensions are out of bounds')
    }
    texSubImageArray(gl, x_off, y_off, mip_level, this.format, this.type, this._mipLevels, data)
  } else {
    throw new Error('gl-texture2d: Unsupported data type')
  }
}


function isPacked(shape, stride) {
  if(shape.length === 3) {
    return  (stride[2] === 1) &&
            (stride[1] === shape[0]*shape[2]) &&
            (stride[0] === shape[2])
  }
  return  (stride[0] === 1) &&
          (stride[1] === shape[0])
}

function texSubImageArray(gl, x_off, y_off, mip_level, cformat, ctype, mipLevels, array) {
  var dtype = array.dtype
  var shape = array.shape.slice()
  if(shape.length < 2 || shape.length > 3) {
    throw new Error('gl-texture2d: Invalid ndarray, must be 2d or 3d')
  }
  var type = 0, format = 0
  var packed = isPacked(shape, array.stride.slice())
  if(dtype === 'float32') {
    type = gl.FLOAT
  } else if(dtype === 'float64') {
    type = gl.FLOAT
    packed = false
    dtype = 'float32'
  } else if(dtype === 'uint8') {
    type = gl.UNSIGNED_BYTE
  } else {
    type = gl.UNSIGNED_BYTE
    packed = false
    dtype = 'uint8'
  }
  var channels = 1
  if(shape.length === 2) {
    format = gl.LUMINANCE
    shape = [shape[0], shape[1], 1]
    array = ndarray(array.data, shape, [array.stride[0], array.stride[1], 1], array.offset)
  } else if(shape.length === 3) {
    if(shape[2] === 1) {
      format = gl.ALPHA
    } else if(shape[2] === 2) {
      format = gl.LUMINANCE_ALPHA
    } else if(shape[2] === 3) {
      format = gl.RGB
    } else if(shape[2] === 4) {
      format = gl.RGBA
    } else {
      throw new Error('gl-texture2d: Invalid shape for pixel coords')
    }
    channels = shape[2]
  } else {
    throw new Error('gl-texture2d: Invalid shape for texture')
  }
  //For 1-channel textures allow conversion between formats
  if((format  === gl.LUMINANCE || format  === gl.ALPHA) &&
     (cformat === gl.LUMINANCE || cformat === gl.ALPHA)) {
    format = cformat
  }
  if(format !== cformat) {
    throw new Error('gl-texture2d: Incompatible texture format for setPixels')
  }
  var size = array.size
  var needsMip = mipLevels.indexOf(mip_level) < 0
  if(needsMip) {
    mipLevels.push(mip_level)
  }
  if(type === ctype && packed) {
    //Array data types are compatible, can directly copy into texture
    if(array.offset === 0 && array.data.length === size) {
      if(needsMip) {
        gl.texImage2D(gl.TEXTURE_2D, mip_level, cformat, shape[0], shape[1], 0, cformat, ctype, array.data)
      } else {
        gl.texSubImage2D(gl.TEXTURE_2D, mip_level, x_off, y_off, shape[0], shape[1], cformat, ctype, array.data)
      }
    } else {
      if(needsMip) {
        gl.texImage2D(gl.TEXTURE_2D, mip_level, cformat, shape[0], shape[1], 0, cformat, ctype, array.data.subarray(array.offset, array.offset+size))
      } else {
        gl.texSubImage2D(gl.TEXTURE_2D, mip_level, x_off, y_off, shape[0], shape[1], cformat, ctype, array.data.subarray(array.offset, array.offset+size))
      }
    }
  } else {
    //Need to do type conversion to pack data into buffer
    var pack_buffer
    if(ctype === gl.FLOAT) {
      pack_buffer = pool.mallocFloat32(size)
    } else {
      pack_buffer = pool.mallocUint8(size)
    }
    var pack_view = ndarray(pack_buffer, shape, [shape[2], shape[2]*shape[0], 1])
    if(type === gl.FLOAT && ctype === gl.UNSIGNED_BYTE) {
      convertFloatToUint8(pack_view, array)
    } else {
      ops.assign(pack_view, array)
    }
    if(needsMip) {
      gl.texImage2D(gl.TEXTURE_2D, mip_level, cformat, shape[0], shape[1], 0, cformat, ctype, pack_buffer.subarray(0, size))
    } else {
      gl.texSubImage2D(gl.TEXTURE_2D, mip_level, x_off, y_off, shape[0], shape[1], cformat, ctype, pack_buffer.subarray(0, size))
    }
    if(ctype === gl.FLOAT) {
      pool.freeFloat32(pack_buffer)
    } else {
      pool.freeUint8(pack_buffer)
    }
  }
}

function initTexture(gl) {
  var tex = gl.createTexture()
  gl.bindTexture(gl.TEXTURE_2D, tex)
  gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.NEAREST)
  gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.NEAREST)
  gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_EDGE)
  gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_EDGE)
  return tex
}

function createTextureShape(gl, width, height, format, type) {
  var maxTextureSize = gl.getParameter(gl.MAX_TEXTURE_SIZE)
  if(width < 0 || width > maxTextureSize || height < 0 || height  > maxTextureSize) {
    throw new Error('gl-texture2d: Invalid texture shape')
  }
  if(type === gl.FLOAT && !gl.getExtension('OES_texture_float')) {
    throw new Error('gl-texture2d: Floating point textures not supported on this platform')
  }
  var tex = initTexture(gl)
  gl.texImage2D(gl.TEXTURE_2D, 0, format, width, height, 0, format, type, null)
  return new Texture2D(gl, tex, width, height, format, type)
}

function createTextureDOM(gl, directData, width, height, format, type) {
  var tex = initTexture(gl)
  gl.texImage2D(gl.TEXTURE_2D, 0, format, format, type, directData)
  return new Texture2D(gl, tex, width, height, format, type)
}

//Creates a texture from an ndarray
function createTextureArray(gl, array) {
  var dtype = array.dtype
  var shape = array.shape.slice()
  var maxSize = gl.getParameter(gl.MAX_TEXTURE_SIZE)
  if(shape[0] < 0 || shape[0] > maxSize || shape[1] < 0 || shape[1] > maxSize) {
    throw new Error('gl-texture2d: Invalid texture size')
  }
  var packed = isPacked(shape, array.stride.slice())
  var type = 0
  if(dtype === 'float32') {
    type = gl.FLOAT
  } else if(dtype === 'float64') {
    type = gl.FLOAT
    packed = false
    dtype = 'float32'
  } else if(dtype === 'uint8') {
    type = gl.UNSIGNED_BYTE
  } else {
    type = gl.UNSIGNED_BYTE
    packed = false
    dtype = 'uint8'
  }
  var format = 0
  if(shape.length === 2) {
    format = gl.LUMINANCE
    shape = [shape[0], shape[1], 1]
    array = ndarray(array.data, shape, [array.stride[0], array.stride[1], 1], array.offset)
  } else if(shape.length === 3) {
    if(shape[2] === 1) {
      format = gl.ALPHA
    } else if(shape[2] === 2) {
      format = gl.LUMINANCE_ALPHA
    } else if(shape[2] === 3) {
      format = gl.RGB
    } else if(shape[2] === 4) {
      format = gl.RGBA
    } else {
      throw new Error('gl-texture2d: Invalid shape for pixel coords')
    }
  } else {
    throw new Error('gl-texture2d: Invalid shape for texture')
  }
  if(type === gl.FLOAT && !gl.getExtension('OES_texture_float')) {
    type = gl.UNSIGNED_BYTE
    packed = false
  }
  var buffer, buf_store
  var size = array.size
  if(!packed) {
    var stride = [shape[2], shape[2]*shape[0], 1]
    buf_store = pool.malloc(size, dtype)
    var buf_array = ndarray(buf_store, shape, stride, 0)
    if((dtype === 'float32' || dtype === 'float64') && type === gl.UNSIGNED_BYTE) {
      convertFloatToUint8(buf_array, array)
    } else {
      ops.assign(buf_array, array)
    }
    buffer = buf_store.subarray(0, size)
  } else if (array.offset === 0 && array.data.length === size) {
    buffer = array.data
  } else {
    buffer = array.data.subarray(array.offset, array.offset + size)
  }
  var tex = initTexture(gl)
  gl.texImage2D(gl.TEXTURE_2D, 0, format, shape[0], shape[1], 0, format, type, buffer)
  if(!packed) {
    pool.free(buf_store)
  }
  return new Texture2D(gl, tex, shape[0], shape[1], format, type)
}

function createTexture2D(gl) {
  if(arguments.length <= 1) {
    throw new Error('gl-texture2d: Missing arguments for texture2d constructor')
  }
  if(!linearTypes) {
    lazyInitLinearTypes(gl)
  }
  if(typeof arguments[1] === 'number') {
    return createTextureShape(gl, arguments[1], arguments[2], arguments[3]||gl.RGBA, arguments[4]||gl.UNSIGNED_BYTE)
  }
  if(Array.isArray(arguments[1])) {
    return createTextureShape(gl, arguments[1][0]|0, arguments[1][1]|0, arguments[2]||gl.RGBA, arguments[3]||gl.UNSIGNED_BYTE)
  }
  if(typeof arguments[1] === 'object') {
    var obj = arguments[1]
    var directData = acceptTextureDOM(obj) ? obj : obj.raw
    if (directData) {
      return createTextureDOM(gl, directData, obj.width|0, obj.height|0, arguments[2]||gl.RGBA, arguments[3]||gl.UNSIGNED_BYTE)
    } else if(obj.shape && obj.data && obj.stride) {
      return createTextureArray(gl, obj)
    }
  }
  throw new Error('gl-texture2d: Invalid arguments for texture2d constructor')
}