classdef GifWriter < handle
    %GIFWRITER  Simple class to create GIFs from figures (parallel-safe)
    %
    % Example:
    %   g = GifWriter('Name','mySim','Parallel',true);
    %   parfor i = 1:10
    %       plot(rand(10,1));
    %       g.addFrame(1,i);
    %   end
    %   g.compile(1);

    properties
        Name (1,:) char = 'default'   % GIF base name
        DelayTime (1,1) double = 0.1  % Frame delay in seconds
        Parallel (1,1) logical = false % Enable parallel-safe mode
        BaseDir (1,:) char            % Base directory for temp frames
        OutputDir (1,:) char          % Final GIF output directory
    end

    methods
        %% Constructor
        function obj = GifWriter(varargin)
            % Parse name/value pairs
            p = inputParser;
            addParameter(p, 'Name', 'default', @ischar);
            addParameter(p, 'DelayTime', 0.1, @isnumeric);
            addParameter(p, 'Parallel', false, @islogical);
            addParameter(p, 'OutputDir', fullfile(pwd, 'gif_output'), @ischar);
            parse(p, varargin{:});

            obj.Name      = p.Results.Name;
            obj.DelayTime = p.Results.DelayTime;
            obj.Parallel  = p.Results.Parallel;
            obj.OutputDir = p.Results.OutputDir;
            obj.BaseDir   = fullfile(obj.OutputDir, 'tmp', obj.Name);

            if ~exist(obj.BaseDir, 'dir'), mkdir(obj.BaseDir); end
            if ~exist(obj.OutputDir, 'dir'), mkdir(obj.OutputDir); end
        end

        %%
        function addFrame(obj, figInput, pos)
            %ADDFRAME  Add a figure frame to the GIF (supports parallel mode)
            %
            % Usage:
            %   obj.addFrame(figHandle)
            %   obj.addFrame(figNum)
            %   obj.addFrame(figHandle, pos)    % parallel mode
            %   obj.addFrame(figNum, pos)
            %
            % In parallel mode, 'pos' must be a unique integer (loop index).

            if nargin < 3, pos = []; end

            % --- Resolve figure handle ---
            if isnumeric(figInput)
                % User passed a figure number
                if ~ishandle(figInput)
                    warning('GifWriter:addFrame', 'Figure %d not found.', figInput);
                    return;
                end
                figHandle = figure(figInput);
            elseif isa(figInput, 'matlab.ui.Figure')
                figHandle = figInput;
            else
                error('GifWriter:addFrame:InvalidInput', ...
                    'Input must be a figure handle or figure number.');
            end

            % --- Parallel-safe frame writing ---
            if obj.Parallel
                if isempty(pos)
                    error('GifWriter:ParallelMode', ...
                        'In parallel mode, provide a unique ''pos'' identifier.');
                end

                % Directory for this figure number
                frameDir = fullfile(obj.BaseDir, sprintf('fig_%d', figHandle.Number));
                if ~exist(frameDir, 'dir')
                    mkdir(frameDir);
                end

                % File path for this frame
                frameFile = fullfile(frameDir, sprintf('frame_%05d.png', pos));

                % Export to PNG (headless-safe)
                exportgraphics(figHandle, frameFile, 'Resolution', 150);

            else
                % --- Serial mode: append directly to GIF ---
                gifFile = fullfile(obj.OutputDir, ...
                    sprintf('%s_fig_%d.gif', obj.Name, figHandle.Number));

                % Export frame temporarily
                tmpFile = [tempname, '.png'];
                exportgraphics(figHandle, tmpFile, 'Resolution', 150);
                img = imread(tmpFile);
                delete(tmpFile);

                % Append to GIF
                [A, map] = rgb2ind(img, 256);
                if ~isfile(gifFile)
                    imwrite(A, map, gifFile, 'gif', ...
                        'LoopCount', Inf, 'DelayTime', obj.DelayTime);
                else
                    imwrite(A, map, gifFile, 'gif', ...
                        'WriteMode', 'append', 'DelayTime', obj.DelayTime);
                end
            end
        end



        %% Compile all PNGs into a GIF (and clean up)
        function compile(obj, fignum)
            figDir = fullfile(obj.BaseDir, sprintf('fig_%d', fignum));
            gifFile = fullfile(obj.OutputDir, sprintf('%s_fig_%d.gif', obj.Name, fignum));

            frames = dir(fullfile(figDir, 'frame_*.png'));
            if isempty(frames)
                warning('GifWriter:NoFrames', 'No frames found for figure %d.', fignum);
                return;
            end

            % Sort by frame name
            [~, idx] = sort({frames.name});
            frames = frames(idx);

            % Combine into a GIF
            for i = 1:numel(frames)
                img = imread(fullfile(frames(i).folder, frames(i).name));
                [A, map] = rgb2ind(img, 256);
                if i == 1
                    imwrite(A, map, gifFile, 'gif', ...
                        'LoopCount', Inf, 'DelayTime', obj.DelayTime);
                else
                    imwrite(A, map, gifFile, 'gif', ...
                        'WriteMode', 'append', 'DelayTime', obj.DelayTime);
                end
            end

            % Clean up temporary frames
            rmdir(figDir, 's');
        end
    end
end