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

function textReplace(
  text: string
) {
  let result = "";

  // 改行削除
  text = text.replaceAll("\n", "");

  // 10文字/1回で改行を追加
  let maxLength = 10;
  if (text.length > maxLength) {
    for (let i = 0; i < text.length; i += maxLength) {
      result += text.substring(i, i + maxLength) + "\n";
    }
    result = result.trimEnd();
  }

  // 80文字以上は「...」で省略
  maxLength = 80;
  if (result.length > maxLength) {
    result = result.substring(0, maxLength)
    + "...";
  }

  return result;
}

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 = "left";
  ctx.textBaseline = "middle";
  let x = 670;
  let y = 480;
  ctx.fillText("-", x, y);
  ctx.fillText(userName, x+40, y, canvas.width-(x+40));

  // ユーザーID描画
  ctx.font = "28px Noto Sans JP";
  ctx.fillStyle = "#3c3c3c";
  ctx.fillText(`@${userID}`, x+120, y+50, canvas.width-(x+120));

  // 本文描画
  ctx.font = "48px Noto Sans JP";
  ctx.textAlign = "center";
  ctx.textBaseline = "middle";
  ctx.fillStyle = "white";
  text = textReplace(text);
  x = 870;
  y = 30;
  ctx.fillText(text, x, y+50);

  // 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 === "Base64") {
    return canvas.toDataURL();
  } else {
    return "Error: The type property is invalid.";
  }
}