import os, struct
import numpy as np
import zlib
import imageio
import cv2

COMPRESSION_TYPE_COLOR = {-1:'unknown', 0:'raw', 1:'png', 2:'jpeg'}
COMPRESSION_TYPE_DEPTH = {-1:'unknown', 0:'raw_ushort', 1:'zlib_ushort', 2:'occi_ushort'}

class RGBDFrame():

 def load(self, file_handle):
 self.camera_to_world = np.asarray(struct.unpack('f'*16, file_handle.read(16*4)), dtype=np.float32).reshape(4, 4)
 self.timestamp_color = struct.unpack('Q', file_handle.read(8))[0]
 self.timestamp_depth = struct.unpack('Q', file_handle.read(8))[0]
 self.color_size_bytes = struct.unpack('Q', file_handle.read(8))[0]
 self.depth_size_bytes = struct.unpack('Q', file_handle.read(8))[0]
 self.color_data = ''.join(struct.unpack('c'*self.color_size_bytes, file_handle.read(self.color_size_bytes)))
 self.depth_data = ''.join(struct.unpack('c'*self.depth_size_bytes, file_handle.read(self.depth_size_bytes)))


 def decompress_depth(self, compression_type):
 if compression_type == 'zlib_ushort':
 return self.decompress_depth_zlib()
 else:
 raise


 def decompress_depth_zlib(self):
 return zlib.decompress(self.depth_data)


 def decompress_color(self, compression_type):
 if compression_type == 'jpeg':
 return self.decompress_color_jpeg()
 else:
 raise


 def decompress_color_jpeg(self):
 return imageio.imread(self.color_data)


class SensorData:

 def __init__(self, filename):
 self.version = 4
 self.load(filename)


 def load(self, filename):
 with open(filename, 'rb') as f:
 version = struct.unpack('I', f.read(4))[0]
 assert self.version == version
 strlen = struct.unpack('Q', f.read(8))[0]
 self.sensor_name = ''.join(struct.unpack('c'*strlen, f.read(strlen)))
 self.intrinsic_color = np.asarray(struct.unpack('f'*16, f.read(16*4)), dtype=np.float32).reshape(4, 4)
 self.extrinsic_color = np.asarray(struct.unpack('f'*16, f.read(16*4)), dtype=np.float32).reshape(4, 4)
 self.intrinsic_depth = np.asarray(struct.unpack('f'*16, f.read(16*4)), dtype=np.float32).reshape(4, 4)
 self.extrinsic_depth = np.asarray(struct.unpack('f'*16, f.read(16*4)), dtype=np.float32).reshape(4, 4)
 self.color_compression_type = COMPRESSION_TYPE_COLOR[struct.unpack('i', f.read(4))[0]]
 self.depth_compression_type = COMPRESSION_TYPE_DEPTH[struct.unpack('i', f.read(4))[0]]
 self.color_width = struct.unpack('I', f.read(4))[0]
 self.color_height = struct.unpack('I', f.read(4))[0]
 self.depth_width = struct.unpack('I', f.read(4))[0]
 self.depth_height = struct.unpack('I', f.read(4))[0]
 self.depth_shift = struct.unpack('f', f.read(4))[0]
 num_frames = struct.unpack('Q', f.read(8))[0]
 self.frames = []
 for i in range(num_frames):
 frame = RGBDFrame()
 frame.load(f)
 self.frames.append(frame)


 def export_depth_images(self, output_path, image_size=None, frame_skip=1):
 if not os.path.exists(output_path):
 os.makedirs(output_path)
 print 'exporting', len(self.frames)//frame_skip, ' depth frames to', output_path
 for f in range(0, len(self.frames), frame_skip):
 depth_data = self.frames[f].decompress_depth(self.depth_compression_type)
 depth = np.fromstring(depth_data, dtype=np.uint16).reshape(self.depth_height, self.depth_width)
 if image_size is not None:
 depth = cv2.resize(depth, (image_size[1], image_size[0]), interpolation=cv2.INTER_NEAREST)
 imageio.imwrite(os.path.join(output_path, str(f) + '.png'), depth)


 def export_color_images(self, output_path, image_size=None, frame_skip=1):
 if not os.path.exists(output_path):
 os.makedirs(output_path)
 print 'exporting', len(self.frames)//frame_skip, 'color frames to', output_path
 for f in range(0, len(self.frames), frame_skip):
 color = self.frames[f].decompress_color(self.color_compression_type)
 if image_size is not None:
 color = cv2.resize(color, (image_size[1], image_size[0]), interpolation=cv2.INTER_NEAREST)
 imageio.imwrite(os.path.join(output_path, str(f) + '.jpg'), color)


 def save_mat_to_file(self, matrix, filename):
 with open(filename, 'w') as f:
 for line in matrix:
 np.savetxt(f, line[np.newaxis], fmt='%f')


 def export_poses(self, output_path, frame_skip=1):
 if not os.path.exists(output_path):
 os.makedirs(output_path)
 print 'exporting', len(self.frames)//frame_skip, 'camera poses to', output_path
 for f in range(0, len(self.frames), frame_skip):
 self.save_mat_to_file(self.frames[f].camera_to_world, os.path.join(output_path, str(f) + '.txt'))


 def export_intrinsics(self, output_path):
 if not os.path.exists(output_path):
 os.makedirs(output_path)
 print 'exporting camera intrinsics to', output_path
 self.save_mat_to_file(self.intrinsic_color, os.path.join(output_path, 'intrinsic_color.txt'))
 self.save_mat_to_file(self.extrinsic_color, os.path.join(output_path, 'extrinsic_color.txt'))
 self.save_mat_to_file(self.intrinsic_depth, os.path.join(output_path, 'intrinsic_depth.txt'))
 self.save_mat_to_file(self.extrinsic_depth, os.path.join(output_path, 'extrinsic_depth.txt'))