%%%%%%%%%%%APPLICATION NOTES%%%%%%%%%%%%%%%%%%%%%%%%
% 
% This function is used to load Zmachine EEG data. Use it as follows,
%        [data,loginfo] = LoadZmachineData('E:\data200\00000.bin');
%
% Return variables: 
%        data: EEG signal in double precision format in micro-volts (full range is -500uV to 500uV)
%        loginfo: this structure contains information about the EEG signal
%                   (sampling frequency, gain, A/D span, A/D resolution, etc). 
%
% If you have already used the Zmachine Data Viewer to import sleep data to your PC, 
% the EEG data is now stored in the PC, and no longer in the Micro SD card of Zmachine. 
% So you need to change the directory name in the above example, 'E:\data200\', 
% to the directory of your PC in which the EEG data is stored, 
% such as 'C:\ProgramData\ZmachineDataViewer\XXXXXXX\Import0\data\', 
% where 'XXXXXXX' is the name that you have used for this person.
%
% The directory 'C:\ProgramData\' is a hidden directory, so you might need to 
% turn on "show hidden files, folders, and drives" in Windows of your PC 
% in order to see 'C:\ProgramData\'. 
%
% Zmachine checks sensor impedances every 15 minutes by default to make sure the good sensor connection. 
% This check last for 1.854 second and the data during this period is not a valid EEG signal. 
%
% Ver 1.2
% Copyright 2016 General Sleep Corporation. All rights reserved. 
% 
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

function [data,loginfo] = LoadZmachineData(file_name)

loginfo = parse_wbpp_log_public(strrep(file_name,'bin','LOG'));

if isempty(loginfo)
    data = [];
    disp('ERROR: Can not open LOG file\n');
    return;
end

counts=loadraw_public(file_name,'uint16');

if isempty(counts)
    data = [];
    loginfo = [];
    disp('ERROR: Can not open DATA file\n');
    return;
end
    
counts=swapbytes(uint16(counts));
ad_bits = loginfo.resolution;

full_range = (loginfo.span_max-loginfo.span_min);
data = double(counts)*full_range/power(2,ad_bits)-full_range/2;

data = data/loginfo.gain*1e6; 


function [data,count]=loadraw_public(filename,type)

if (nargin == 1)
    type = 'double';
end

fid=fopen(filename,'r');

if (fid == -1)  % no such file
    data = [];
    count = 0;
else
    [data,count]=fread(fid,type);
    fclose(fid);
end

function info = parse_wbpp_log_public(filename)

fid = fopen(filename);
temp = textscan(fid,'%s','delimiter','\n');
fclose(fid);

for i = 1:length(temp{1})
    if strcmp(temp{1}{i},'Sample Rate, in Hz') == 1,  info.fs = str2double(temp{1}{i+1});  end
    if strcmp(temp{1}{i},'Amplification') == 1,  info.gain = str2double(temp{1}{i+1});  end
    if strcmp(temp{1}{i},'Span Max, in Volts') == 1,  info.span_max = str2double(temp{1}{i+1});  end
    if strcmp(temp{1}{i},'Span Min, in Volts') == 1,  info.span_min = str2double(temp{1}{i+1});  end
    if strcmp(temp{1}{i},'Bits of Resolution') == 1,  info.resolution = str2double(temp{1}{i+1});  end
    if strcmp(temp{1}{i},'Impedance Checking Amplification') == 1,  info.impedance_gain = str2double(temp{1}{i+1});  end   
end