package og;

import og.ContentLoader.Snippet;

import og.SyntaxHighlighter.Token;

import java.awt.BasicStroke;

import java.awt.Color;

import java.awt.Font;

import java.awt.Graphics2D;

import java.awt.RenderingHints;

import java.awt.Shape;

import java.awt.font.FontRenderContext;

import java.awt.geom.RoundRectangle2D;

import java.awt.image.BufferedImage;

import java.io.IOException;

import java.nio.file.Path;

import java.util.List;

import javax.imageio.ImageIO;

import static og.Layout.*;

import static og.Palette.*;

/**

* Renders OG card PNGs directly with Graphics2D — no SVG intermediary,

* no Batik dependency. Produces 2× resolution (2400×1260) images.

*/

public final class PngRenderer {

static final int SCALE = 2;

// Reuse a single BufferedImage across all cards to avoid 12MB humongous allocations per card

static final BufferedImage SHARED_IMG = new BufferedImage(W * SCALE, H * SCALE, BufferedImage.TYPE_INT_RGB);

public static void generate(Snippet s, Path outputPath) throws IOException {

var g = SHARED_IMG.createGraphics();

g.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);

g.setRenderingHint(RenderingHints.KEY_TEXT_ANTIALIASING, RenderingHints.VALUE_TEXT_ANTIALIAS_LCD_HRGB);

g.setRenderingHint(RenderingHints.KEY_RENDERING, RenderingHints.VALUE_RENDER_QUALITY);

g.setRenderingHint(RenderingHints.KEY_FRACTIONALMETRICS, RenderingHints.VALUE_FRACTIONALMETRICS_ON);

g.scale(SCALE, SCALE);

// White fill (clears previous card)

g.setColor(Color.WHITE);

g.fillRect(0, 0, W, H);

drawCard(g, s);

g.dispose();

ImageIO.write(SHARED_IMG, "PNG", outputPath.toFile());

}

static void drawCard(Graphics2D g, Snippet s) {

// Background with rounded corners

var bg = new RoundRectangle2D.Double(0, 0, W, H, 16, 16);

g.setColor(Palette.color(BG));

g.fill(bg);

g.setColor(Palette.color(BORDER));

g.setStroke(new BasicStroke(1f));

g.draw(new RoundRectangle2D.Double(0.5, 0.5, W - 1, H - 1, 16, 16));

drawHeader(g, s);

// Compute font size and fit lines

var rawOldLines = s.oldCode().lines().toList();

var rawModernLines = s.modernCode().lines().toList();

int fontSize = bestFontSize(rawOldLines, rawModernLines);

int lineH = (int) (fontSize * LINE_HEIGHT_RATIO);

var oldLines = fitLines(rawOldLines, fontSize);

var modernLines = fitLines(rawModernLines, fontSize);

int leftX = PAD;

int rightX = PAD + COL_W + 20;

drawCodePanel(g, oldLines, leftX, OLD_BG, OLD_ACCENT,

"\u2717 " + s.oldLabel(), fontSize, lineH);

drawCodePanel(g, modernLines, rightX, MODERN_BG, GREEN,

"\u2713 " + s.modernLabel(), fontSize, lineH);

drawFooter(g, s);

}

static void drawHeader(Graphics2D g, Snippet s) {

var catText = s.catDisplay();

var categoryFont = FontManager.getFont("Inter-SemiBold.ttf", 13f);

var titleFont = FontManager.getFont("Inter-Bold.ttf", 24f);

// Category badge

var fm = g.getFontMetrics(categoryFont);

int badgeW = fm.stringWidth(catText) + 16;

g.setColor(Palette.color(BADGE_BG));

g.fill(new RoundRectangle2D.Double(PAD, 28, badgeW, 22, 6, 6));

g.setFont(categoryFont);

g.setColor(Palette.color(TEXT_MUTED));

g.drawString(catText, PAD + 8, 43);

// Title

g.setFont(titleFont);

g.setColor(Palette.color(TEXT));

g.drawString(s.title(), PAD, 76);

}

static void drawCodePanel(Graphics2D g, List<String> lines, int panelX,

String bgHex, String labelColorHex, String labelText,

int fontSize, int lineH) {

// Panel background

var panelRect = new RoundRectangle2D.Double(panelX, CODE_TOP, COL_W, CODE_H, 8, 8);

g.setColor(Palette.color(bgHex));

g.fill(panelRect);

g.setColor(Palette.color(BORDER));

g.setStroke(new BasicStroke(0.5f));

g.draw(panelRect);

// Label

var labelFont = FontManager.getFont("Inter-SemiBold.ttf", 11f);

g.setFont(labelFont);

g.setColor(Palette.color(labelColorHex));

g.drawString(labelText.toUpperCase(), panelX + 14, CODE_TOP + 26);

// Code lines (clipped to panel)

Shape oldClip = g.getClip();

g.setClip(panelRect);

var codeFont = FontManager.getFont("JetBrainsMono-Regular.ttf", (float) fontSize);

g.setFont(codeFont);

var frc = g.getFontRenderContext();

int codeY = CODE_TOP + 52;

for (int i = 0; i < lines.size(); i++) {

var tokens = SyntaxHighlighter.tokenize(lines.get(i));

drawTokens(g, tokens, panelX + 14, codeY + i * lineH, codeFont, frc);

}

g.setClip(oldClip);

}

static void drawTokens(Graphics2D g, List<Token> tokens, int x, int y,

Font codeFont, FontRenderContext frc) {

float curX = x;

for (var token : tokens) {

g.setColor(token.color() != null

? Palette.color(token.color())

: Palette.color(SYN_DEFAULT));

g.drawString(token.text(), curX, y);

curX += (float) codeFont.getStringBounds(token.text(), frc).getWidth();

}

}

static void drawFooter(Graphics2D g, Snippet s) {

var footerFont = FontManager.getFont("Inter-Medium.ttf", 13f);

var brandFont = FontManager.getFont("Inter-Bold.ttf", 14f);

// JDK version

g.setFont(footerFont);

g.setColor(Palette.color(TEXT_MUTED));

g.drawString("JDK %s+".formatted(s.jdkVersion()), PAD, H - 22);

// Brand (right-aligned)

g.setFont(brandFont);

g.setColor(Palette.color(ACCENT));

var brand = "javaevolved.github.io";

var fm = g.getFontMetrics(brandFont);

g.drawString(brand, W - PAD - fm.stringWidth(brand), H - 22);

}

private PngRenderer() {}

}