const { createCanvas, loadImage, GlobalFonts } = require("@napi-rs/canvas");
const { writeFile } = require("node:fs/promises");
const { parentPort, workerData } = require("node:worker_threads");

function clamp(value, min, max) {
  return Math.min(max, Math.max(min, value));
}

function hexToRgba(hex, opacity) {
  let value = hex.replace("#", "");
  if (value.length === 3) {
    value = value
      .split("")
      .map((char) => char + char)
      .join("");
  }

  let alpha = clamp(opacity, 0, 1);
  if (value.length === 8) {
    alpha *= parseInt(value.slice(6, 8), 16) / 255;
    value = value.slice(0, 6);
  }

  const r = parseInt(value.slice(0, 2), 16);
  const g = parseInt(value.slice(2, 4), 16);
  const b = parseInt(value.slice(4, 6), 16);
  return `rgba(${r}, ${g}, ${b}, ${alpha})`;
}

function buildCanvasFont(style) {
  const italic = style.italic ? "italic " : "";
  const weight = style.bold ? "700 " : "400 ";
  return `${italic}${weight}${style.fontSize}px "${style.fontFamily}"`;
}

function drawIdText(ctx, text, imageWidth, imageHeight, style) {
  const x = (style.xPercent / 100) * imageWidth;
  const y = (style.yPercent / 100) * imageHeight;
  ctx.font = buildCanvasFont(style);
  ctx.textAlign = style.align;
  ctx.textBaseline = "alphabetic";
  const metrics = ctx.measureText(text);
  const ascent = metrics.actualBoundingBoxAscent ?? style.fontSize * 0.8;
  const descent = metrics.actualBoundingBoxDescent ?? style.fontSize * 0.2;
  const baselineY = y + (ascent - descent) / 2;

  ctx.save();
  ctx.fillStyle = style.color;
  if (style.shadowEnabled) {
    ctx.shadowColor = hexToRgba(style.shadowColor, style.shadowOpacity);
    ctx.shadowBlur = style.shadowBlur;
    ctx.shadowOffsetX = style.shadowOffsetX;
    ctx.shadowOffsetY = style.shadowOffsetY;
  } else {
    ctx.shadowColor = "transparent";
    ctx.shadowBlur = 0;
    ctx.shadowOffsetX = 0;
    ctx.shadowOffsetY = 0;
  }

  if (style.outlineEnabled && style.outlineWidth > 0) {
    ctx.strokeStyle = hexToRgba(style.outlineColor, style.outlineOpacity);
    ctx.lineWidth = style.outlineWidth;
    ctx.lineJoin = "round";
    ctx.miterLimit = 2;
    ctx.strokeText(text, x, baselineY);
    ctx.shadowColor = "transparent";
  }

  ctx.fillText(text, x, baselineY);
  ctx.restore();
}

async function run() {
  const { imagePath, fonts, style, tasks } = workerData;

  for (const font of fonts) {
    GlobalFonts.registerFromPath(font.path, font.family);
  }

  const image = await loadImage(imagePath);
  const canvas = createCanvas(image.width, image.height);
  const ctx = canvas.getContext("2d");

  for (const task of tasks) {
    ctx.drawImage(image, 0, 0);
    drawIdText(ctx, task.text, image.width, image.height, style);
    await writeFile(task.outPath, await canvas.encode("png"));
    parentPort?.postMessage({ type: "progress" });
  }
}

run().catch((error) => {
  throw error;
});