import { createCanvas, loadImage, registerFont } from "canvas";
import { writeFileSync } from "fs";
import sharp from "sharp";
import { MiQOptions } from "./miq";

function maxLengthCut(
  text: string,
  maxLength: number,
) {
  if (text.length > maxLength) {
    text = text.substring(0, maxLength)
    + "...";
  }

  return text;
}

function autoLineBreak(
  text: string,
  maxWidth: number,
  font: string = "48px Noto Sans JP"
): string {
  const ctx = createCanvas(maxWidth, 100).getContext("2d");
  ctx.font = font;

  const lines: string[] = [];
  let currentLine = "";

  for (let i = 0; i < text.length; i++) {
    const char = text[i];
    const testLine = currentLine + char;
    const width = ctx.measureText(testLine).width;

    if (width > maxWidth) {
      lines.push(currentLine);
      currentLine = char;

      while (ctx.measureText(currentLine).width > maxWidth && currentLine.length > 1) {
        const cutPoint = currentLine.length - 1;
        lines.push(currentLine.slice(0, cutPoint));
        currentLine = currentLine.slice(cutPoint);
      }
    } else {
      currentLine = testLine;
    }
  }

  if (currentLine) lines.push(currentLine);

  return lines.join("\n");
}

function textReplace(
  text: string,
  maxWidth: number
) {
  text = text.replaceAll("\n", "");
  text = maxLengthCut(text, 100);
  text = autoLineBreak(text, maxWidth);

  return text;
}

async function iconReplace(
  color: boolean,
  iconURL: string,
) {
  let result = "";

  const buffer = await(await fetch(iconURL, {
    method: "GET",
    cache: "no-store",
  })).arrayBuffer();

  if (color) {
    const img = await sharp(Buffer.from(buffer))
    .png()
    .toBuffer();

    result = `data:image/png;base64,${img.toString("base64")}`;
  } else {
    const img = await sharp(Buffer.from(buffer))
    .png()
    .grayscale()
    .toBuffer();

    result = `data:image/png;base64,${img.toString("base64")}`;
  }

  return result;
}

/**
 * A function to generate
 * Make it a quote on Node.js.
*/
export default async function MiQ({
  type,
  color,
  text,
  iconURL,
  userName,
  userID,
}: MiQOptions) {
  // フォント読み込み
  registerFont("miq/fonts/NotoSansJP.ttf", { family: "Noto Sans JP" });

  // 初期化
  const canvas = createCanvas(1200, 630);
  const ctx = canvas.getContext("2d");

  // 背景描画
  ctx.fillStyle = "black";
  ctx.fillRect(0, 0, canvas.width, canvas.height);

  // アイコン描画
  const iconImg = await loadImage(await iconReplace(
    color,
    iconURL,
  ));
  const iconSize = canvas.height;
  ctx.drawImage(iconImg, 0, 0, iconSize, iconSize);

  // ユーザー名描画
  ctx.font = "38px Noto Sans JP";
  ctx.fillStyle = "white";
  ctx.textAlign = "center";
  ctx.textBaseline = "middle";
  let x = 910;
  let y = 480;
  ctx.fillText(`- ${userName}`, x, y, canvas.width-x);

  // ユーザーID描画
  ctx.font = "28px Noto Sans JP";
  ctx.fillStyle = "#3c3c3c";
  ctx.fillText(`@${userID}`, x, y+50, canvas.width-x);

  // 本文描画
  const maxWidth = canvas.width - iconSize;
  text = textReplace(text, maxWidth);
  ctx.font = "48px Noto Sans JP";
  ctx.textAlign = "center";
  ctx.textBaseline = "middle";
  ctx.fillStyle = "white";
  ctx.fillText(text, x, 80);

  // フェード描画
  const fadeColor = "black";
  const gradient = ctx.createLinearGradient(0, 0, canvas.width, 0);
  gradient.addColorStop(0, "rgba(0, 0, 0, 0)");
  gradient.addColorStop(0.5, fadeColor);
  ctx.fillStyle = gradient;
  ctx.fillRect(0, 0, iconSize, canvas.height);

  // 返答
  if (type === "Buffer") {
    return canvas.toBuffer();
  } else if (type === "Base64Data") {
    return canvas.toDataURL()
    .replace("data:image/png;base64,", "");
  } else if (type === "Base64URL") {
    return canvas.toDataURL();
  } else {
    return "Error: The type property is invalid.";
  }
}

/*(async () => {
  writeFileSync(
    "miq/a.png",
    await MiQ({
      type: "Buffer",
      color: false,
      text: "テスト",
      iconURL: "https://media.uwuzu.net/uwuzu-net/files/3ov7dghkn7.webp",
      userName: "Last2014",
      userID: "last2014",
    }),
    "utf-8"
  );
})()*/