coding UTF-8;  // Specify character encoding (to prevent mojibake)

// Import libraries
import GUI;         // Library for GUI components like windows and buttons
import Graphics;    // Library for handling image data and graphic resources
import Graphics2D;  // Library for 2D rendering
import File;        // Library for handling file and folder information
import system.Int;  // Library providing helper functions for integers


// Constant settings for GUI
const int DEFAULT_WINDOW_WIDTH = 800;  // Initial window width
const int DEFAULT_WINDOW_HEIGHT = 700; // Initial window height
const int CONTROL_AREA_HEIGHT = 60;    // Height of the control section at the bottom of the window
const int PLAY_BUTTON_WIDTH = 140;     // Width of the play/stop button
const string PLAY_TEXT = "PLAY";       // Label text for the play button
const string STOP_TEXT = "STOP";       // Label text for the stop button
const int BACKGROUND_COLOR[] = { 50, 50, 50, 255 }; // Background color (R,G,B,Alpha)

// Constant settings for file paths
const string DEFAULT_DIRECTORY_PATH = "./sample"; // Default folder path
const string DEFAULT_FILE_NAME = "image"; // Default image file name (excluding number and extension)
const string FILE_EXTENSION_SELECT_MESSAGE = "- Select Extension -"; // Message shown when selecting file extension
const string FILE_EXTENSIONS[] = { FILE_EXTENSION_SELECT_MESSAGE, ".png", ".jpg" }; // Extension options

// Other constant settings
const int DEFAULT_WAIT = 30; // Default interval between frames (milliseconds)
const int FILE_NUMBER_SEARCH_LIMIT = 1000; // Max number to search for start of sequence

// Variables related to file names and paths (set in the configure function)
string directoryPath; // Path to the folder containing image files
string fileNameHead;  // File name prefix (excluding number and extension)
string extension;     // File extension (including dot)
int fileNumberBegin;  // Starting number of the sequence
int fileNumberEnd;    // Ending number of the sequence

// Variables related to GUI layout
int windowWidth = DEFAULT_WINDOW_WIDTH;   // Width of the image display window (can change)
int windowHeight = DEFAULT_WINDOW_HEIGHT; // Height of the image display window (can change)
int screenWidth;   // Width of the display screen (set in the "configure" function)
int screenHeight;  // Height of the display screen (set in the "configure" function)

// Variables for GUI components
int screenWindow = NULL;     // ID of the image display window
int screenImageLabel = NULL; // ID of the image display label
int screenGraphics = NULL;   // ID of the graphics resource for drawing on the screen
int screenRenderer = NULL;   // ID of the renderer (drawing engine) for the screen
int playButton = NULL;  // ID of the play/stop button
int seekSlider = NULL;  // ID of the seek bar
int waitField = NULL;   // ID of the field for setting frame interval
int seekLabel = NULL;   // ID of the label next to the seek bar
int waitLabel = NULL;   // ID of the label next to the interval input field

// Variables related to images
int totalNumberOfImages;    // Total number of image files
string imageFilePaths[];    // Array to store paths of all image files
int imageGraphicsBuffers[]; // Array to buffer image contents (stores graphics resource IDs for each image)

// Variables for control
bool continuesMainLoop = true;  // Controls whether the main loop continues (set to false to exit)
bool windowSizeChanged = false; // Set to true when the window is resized, triggers re-layout
bool playing = true;            // True when playing, false when stopped
bool bufferingEnabled;          // Controls whether image buffering is enabled (set in the configure function)


// ============================================================
// Main process - This function runs automatically on startup
// ============================================================

void main() {
	
	// Perform configuration based on user input
	configure();
	
	// Initialize drawing-related resources
	initializeGraphicsResources();
	
	// Initialize GUI components
	initializeGUI();
	
	// Apply layout settings to the GUI
	updateLayout();
	
	// Once the image window is open, hide the CUI console window to avoid clutter
	hide();
	
	// Variable to store the last displayed image index, to avoid redundant redraws
	int lastImageIndex = -1;
	
	// Main loop: updates and redraws the image on each cycle
	while (continuesMainLoop) {
		
		// Get the image index to display, based on the seek bar's position
		int imageIndex = getComponentInt(seekSlider);
		
		// Draw the image on the screen (skip if the image hasn't changed)
		if (imageIndex != lastImageIndex) {
			drawScreen(imageIndex);
		}
		
		// Handle window resize
		if (windowSizeChanged) {    // This variable is set to true in "onWindowResize" when a resize is detected
			updateLayout();         // Reapply GUI layout
			drawScreen(imageIndex); // Redraw image on screen
			windowSizeChanged = false; // Reset resize flag
		}
		
		// Store the index of the last drawn image
		lastImageIndex = imageIndex;
		
		// Wait for the specified interval before the next frame (animation delay)
		int wait = getWaitValue();
		sleep(wait);
		
		// Advance time if animation is playing
		if (playing) {
			
			// Increment image index; loop back to start if at the end
			imageIndex++;
			if (imageIndex == totalNumberOfImages) {
				imageIndex = 0;
			}
			
			// Update the seek bar to match the new image index
			setComponentInt(seekSlider, imageIndex);
		}
	}
	
	// Exit the program when the main loop ends
	exit();
}


// ==================================================
// Function for handling configuration via user input
// ==================================================

void configure() {
	
	// Select the folder to load image files from (if skipped, the "sample" folder is used)
	directoryPath = DEFAULT_DIRECTORY_PATH;
	if (confirm("Do you want to specify the folder for loading images?", "(If you select 'No', the '" + DEFAULT_DIRECTORY_PATH + "' folder will be used)")) {
		directoryPath = choose("Select the folder to load images from", ".");
	}
	println("Image folder = " + directoryPath);
	
	// Enter the file name (excluding number and extension)
	fileNameHead = input("Enter the image file name (excluding number and extension)", DEFAULT_FILE_NAME);
	println("Image file name = " + fileNameHead);
	
	// Select the file extension
	extension = select(FILE_EXTENSIONS);
	while (extension == FILE_EXTENSION_SELECT_MESSAGE) {
		extension = select(FILE_EXTENSIONS);
	}
	println("Extension = " + extension);
	
	// Search for image files in the folder and determine the start and end of the sequence
	scanFileIndex();
	
	// Choose whether to enable image buffering
	bufferingEnabled = confirm(
		"Enable image buffering?",
		"Buffering helps animations play more smoothly.",
		"It also reduces stress on HDDs, especially on older PCs.",
		"However, buffering uses more memory, which may cause issues in low-memory environments."
	);
}


// ==================================================================================
// Function to search for image files and determine the start and end of the sequence
// ==================================================================================

void scanFileIndex() {
	
	println("Searching for files...");
	
	// Search for the starting number and set it to "fileNumberBegin"
	fileNumberBegin = 0;
	while (true) {
		
		// Starting from 0, increment fileNumberBegin by 1 and
		// check if a file with that number exists;
		// the first one found will be considered the start of the sequence
		
		string fileName = fileNameHead + fileNumberBegin + extension;
		string filePath = getFilePath(fileName, directoryPath);
		if (exists(filePath)) {
			println("Start file: " + filePath);
			break;
		}
		
		if(fileNumberBegin >= FILE_NUMBER_SEARCH_LIMIT) {
			popup("Searched up to file number " + FILE_NUMBER_SEARCH_LIMIT + " but no sequential file was found.");
			exit();
		}
		
		fileNumberBegin++;
	}
	
	
	println("Start number = " + fileNumberBegin);
	
	// Search for the ending number and set it to fileNumberEnd
	fileNumberEnd = fileNumberBegin;
	while (true) {
		
		// Starting from fileNumberBegin, increment fileNumberEnd by 1
		// and check if a file with that number exists;
		// when no such file is found, set (current number - 1) as the end of the sequence
		
		string fileName = fileNameHead + fileNumberEnd + extension;
		string filePath = getFilePath(fileName, directoryPath);
		if (!exists(filePath)) {
			fileNumberEnd--;
			break;
		}
		fileNumberEnd++;
	}
	
	println("End number = " + fileNumberEnd);
}


// ==================================================
// Initialization for rendering-related resources
// ==================================================

void initializeGraphicsResources() {
	
	// Calculate and set the total number of image files
	totalNumberOfImages = fileNumberEnd - fileNumberBegin + 1;
	
	// Allocate arrays for file paths and buffers, using the total image count
	alloc(imageFilePaths, totalNumberOfImages);
	alloc(imageGraphicsBuffers, totalNumberOfImages);
	
	// Store the full file paths in the array
	for (int i=0; i<totalNumberOfImages; i++) {
		string fileName = fileNameHead + (fileNumberBegin + i) + extension;
		imageFilePaths[i] = getFilePath(fileName, directoryPath);
	}
	
	// If buffering is enabled,
	// load all image files in advance and create graphics resources,
	// then store them in the buffer array
	if (bufferingEnabled) {
		for (int i=0; i<totalNumberOfImages; i++) {
			println("Preparing image buffer: " + imageFilePaths[i]);
			imageGraphicsBuffers[i] = newGraphics(imageFilePaths[i]);
		}
		println("Image buffer preparation complete");
	}
	
	// Create the graphics resource and renderer (drawing engine) for the screen
	screenGraphics = newGraphics();
	screenRenderer = newGraphics2DRenderer(1, 1, screenGraphics); // 幅や高さはupdateLayout関数で再設定
}


// ==================================================
// Initialization for screen (GUI) components
// ==================================================

void initializeGUI() {
	
	// Create the image display window
	screenWindow = newWindow(0, 0, DEFAULT_WINDOW_WIDTH, DEFAULT_WINDOW_HEIGHT, "Image File Animator");
	
	// Create the image display label and place it in the window
	screenImageLabel = newImageLabel(0, 0, 0, 0, screenGraphics); // Width and height will be updated in updateLayout()
	mountComponent(screenImageLabel, screenWindow);
	
	// Create the play/stop button and place it in the window
	playButton = newButton(0, 0, 0, 0, STOP_TEXT); // Width, height, and position will be set in updateLayout()
	setComponentFontSize(playButton, 20);
	mountComponent(playButton, screenWindow);
	
	// Create the seek bar (horizontal slider) and place it in the window
	seekSlider = newHorizontalSlider(0, 0, 0, 0, 0, 0, totalNumberOfImages-1); // Same for width, height, and position
	mountComponent(seekSlider, screenWindow);
	
	// Create the info label to the left of the seek bar and place it in the window
	seekLabel = newTextLabel(0, 0, 0, 0, ""); // Same for width, height, and position
	mountComponent(seekLabel, screenWindow);
	
	// Create the interval (wait time) input field and place it in the window
	waitField = newTextField(0, 0, 0, 0, (string)DEFAULT_WAIT); // Same for width, height, and position
	mountComponent(waitField, screenWindow);
	
	// Create the label next to the interval input field and place it in the window
	waitLabel = newTextLabel(0, 0, 0, 0, "Update Interval (ms) ="); // Same for width, height, and position
	mountComponent(waitLabel, screenWindow);
}


// =======================================================
// Function to get the user-specified interval (wait time)
// =======================================================

int lastWait = -1; // Store the previous value to avoid duplicate warning messages
int getWaitValue() {
	
	// Get the value from the wait time input field as a string
	string waitText = getComponentString(waitField);
	
	// If the input is not a valid integer, wait briefly and try again (in case the user is editing)
	while (!isInt(waitText)) {
		waitText = getComponentString(waitField);
		sleep(100);
	}
	
	// If the value starts with 0 and has more than one digit, remove the leading zero
	// (to avoid interpretation as old-style octal literals, which are deprecated and may trigger warnings)
	while (countText(waitText) >= 2 && checkText(waitText, "0", Text.START)) {
		waitText = replaceText(waitText, "0", "", Text.FIRST);
	}
	
	// Convert the string to an integer, and show a warning if the value is unusually large
	int wait = (int)waitText;
	if (wait >= 10000 && wait != lastWait) {
		if( !confirm("A large value (10 seconds or more) is specified for the interval. Are you sure you want to apply it?") ) {
			waitText = (string)DEFAULT_WAIT;
			setComponentText(waitField, waitText);
			wait = DEFAULT_WAIT;
		}
	}
	
	// Store the value that triggered a warning, to skip future warnings for the same value
	lastWait = wait; 
	
	return wait;
}


// ============================================================
// Function to handle layout of GUI components on the screen
// ============================================================

void updateLayout() {
	
	// Get the inner size of the window and calculate the display area size
	int windowInnnerSize[] = getComponentSize(screenWindow, INNER);
	screenWidth = windowInnnerSize[0];
	screenHeight = windowInnnerSize[1] - CONTROL_AREA_HEIGHT;
	
	// Update the renderer and image label with the new screen size
	setGraphics2DSize(screenRenderer, screenWidth, screenHeight);
	setComponentSize(screenImageLabel, screenWidth, screenHeight);
	
	// Layout settings for the control panel at the bottom of the window
	
	// Play/stop button
	setComponentSize(playButton, PLAY_BUTTON_WIDTH, CONTROL_AREA_HEIGHT);
	setComponentLocation(playButton, 0, screenHeight);
	
	// Seek bar
	setComponentSize(seekSlider, screenWidth - PLAY_BUTTON_WIDTH - 180, 20);
	setComponentLocation(seekSlider, PLAY_BUTTON_WIDTH + 160, screenHeight + 10);
	
	// Wait time input field
	setComponentSize(waitField, 100, 20);
	setComponentLocation(waitField, PLAY_BUTTON_WIDTH + 160, screenHeight + 30);
	
	// Info label to the left of the seek bar
	setComponentSize(seekLabel, 140, 20);
	setComponentLocation(seekLabel, PLAY_BUTTON_WIDTH + 20, screenHeight + 10);
	
	// Description label to the left of the wait time input
	setComponentSize(waitLabel, 140, 20);
	setComponentLocation(waitLabel, PLAY_BUTTON_WIDTH + 20, screenHeight + 30);
	
	// Repaint the labels
	paintComponent(seekLabel);
	paintComponent(waitLabel);
}


// ==================================================
// Function to draw an image on the screen
// ==================================================

void drawScreen(int i) {
	
	// Declare a variable to store the ID of the graphics resource for the image
	int imageFileGraphics;
	
	// If buffering is enabled, use the preloaded graphics resource
	if (bufferingEnabled) {
		imageFileGraphics = imageGraphicsBuffers[i];
	
	// If buffering is disabled, load the image from the file path and create a graphics resource
	} else {
		imageFileGraphics = newGraphics(imageFilePaths[i]);
	}
	
	// Get the width and height of the image
	int imageWidth = getGraphicsWidth(imageFileGraphics);
	int imageHeight = getGraphicsHeight(imageFileGraphics);
	
	// Calculate the aspect ratio of the image
	float imageAspectRatio = (float)imageWidth / (float)imageHeight;
	
	// Calculate the width and height to draw the image, fitting it to the screen while preserving aspect ratio
	int drawWidth = screenHeight * imageAspectRatio;
	int drawHeight = screenHeight;
	if (drawWidth > screenWidth) {
		drawWidth = screenWidth;
		drawHeight = screenWidth / imageAspectRatio;
	}
	
	// Calculate the top-left corner position to center the image on the screen
	int drawX = screenWidth/2 - drawWidth/2;
	int drawY = screenHeight/2 - drawHeight/2;
	
	// Fill the screen with the background color
	setDrawColor(screenRenderer, BACKGROUND_COLOR);
	drawRectangle(screenRenderer, 0, 0, screenWidth, screenHeight, true);
	
	// Draw the image on top of the background
	drawImage(screenRenderer, drawX, drawY, drawWidth, drawHeight, imageFileGraphics);
	int imageNumber = getComponentInt(seekSlider) + fileNumberBegin;
	setComponentString(seekLabel, "Image Number=" + imageNumber);
	
	// Repaint the image display label
	paintComponent(screenImageLabel);
	
	// If buffering is disabled, delete the graphics resource after each draw
	if (!bufferingEnabled) {
		deleteGraphics(imageFileGraphics);
	}
}


// ============================================================
// Function called when a button is clicked (event handler)
// ============================================================

void onButtonClick(int id) {
	
	// If the play/stop button is clicked
	if (id == playButton) {
		
		// Toggle between playing and stopped states
		playing = !playing;
		
		// Update the button label accordingly
		if (playing) {
			setComponentString(playButton, STOP_TEXT);
		} else {
			setComponentString(playButton, PLAY_TEXT);
		}
	}
}


// ============================================================
// Function called when the window is resized (event handler)
// ============================================================

void onWindowResize(int id, int width, int height) {
	
	// If the image display window is resized
	if (id == screenWindow) {
		
		// Set the resize flag to true to trigger layout update in the main loop
		// (Avoid heavy processing here since resize events may fire repeatedly)
		windowSizeChanged = true;
	}
}


// ============================================================
// Function called when the window is closed (event handler)
// ============================================================
void onWindowClose (int id) {
	
	// If the image display window is closed
	if (id == screenWindow) {
		
		// Exit the main loop and end the program
		continuesMainLoop = false;
	}
}