% Generic logger that executes MeasFcn according to MeasTimer, stores the
% results and optionally continuously saves them. 
% MeasFcn should be a function with no arguments.  
% MeasFcn need to return a row vector of numbers in order to save the log
% in text format or display it. With other kinds of returned values the 
% log can still be recorded, but not saved or dispalyed.

classdef MyLogger < handle
    
    properties (Access=public)
        % Timer object
        MeasTimer
        
        % Function that provides data to be recorded
        MeasFcn = @()0
        save_cont = false
        
        % Format for displaying last reading (label: value)
        disp_fmt = '%15s: %.2e'
    end
    
    properties (SetAccess=protected, GetAccess=public)
        % If last measurement was succesful
        % 0-false, 1-true, 2-never measured
        last_meas_stat = 2 
        
        % MyLog object to store the recorded data
        Log
    end
    
    events
        % Event that is triggered each time MeasFcn is successfully executed
        NewData
    end
    
    methods (Access=public)
        function this = MyLogger(varargin)
            P=MyClassParser(this);
            processInputs(P, this, varargin{:});
            
            this.Log=MyLog(P.unmatched_nv{:});
                 
            if ismember('MeasTimer', P.UsingDefaults)
                % Create and confitugure timer unless it was supplied
                % externally in varargin
                this.MeasTimer = timer();
                this.MeasTimer.BusyMode = 'drop';
                % Fixed spacing mode of operation does not follow the
                % period very well, but is robust with respect to
                % function execution delays
                this.MeasTimer.ExecutionMode = 'fixedSpacing';
            end 
            
            this.MeasTimer.TimerFcn = @(~,event)LoggerFcn(this,event);
        end
        
        function delete(this)         
            %stop and delete the timer
            stop(this.MeasTimer);
            delete(this.MeasTimer);
        end
        
        % save the entire data record
        function saveLog(this)
            saveLog(this.Log)
        end
        
        function clearLog(this)
            clearLog(this.Log)
        end
        
        function start(this)
            start(this.MeasTimer);
        end
        
        function stop(this)
            stop(this.MeasTimer);
        end
        
        function str = dispLastReading(this)
            if isempty(this.timestamps)
                str = '';
            else
                str = ['Last reading ',char(this.timestamps(end)),newline];
                last_data = this.data{end};
                for i=1:length(last_data)
                    if length(this.data_headers)>=i
                        lbl = this.data_headers{i};
                    else
                        lbl = sprintf('data%i',i);
                    end
                    str = [str,...
                        sprintf(this.disp_fmt,lbl,last_data(i)),newline];
                end
            end
        end
    
    end
    
    methods (Access=protected)
        % Perform measurement and append point to the log
        function LoggerFcn(this, event)
            time = datetime(event.Data.time);
            try
                meas_result = this.MeasFcn();
                this.last_meas_stat=1; % last measurement ok
            catch
                warning(['Logger cannot take measurement at time = ',...
                    datestr(time)]);
                this.last_meas_stat=0; % last measurement not ok
            end
            
            if this.last_meas_stat==1 
                % append measurement result together with time stamp
                appendPoint(this.Log, time, meas_result,...
                    'save', this.save_cont);
                triggerNewData(this);
            end
        end
        
        %Triggers event for acquired data
        function triggerNewData(this)
            notify(this,'NewData')
        end
    end
end