const { createCanvas, loadImage, registerFont } = require("canvas");
const exiftool = require("exiftool-vendored");
const fs = require("fs");
const path = require("path");

// Optional: Register a custom font if needed (must be a .ttf or .otf file)
registerFont(path.join(__dirname, "fonts", "OpenSans-Regular.ttf"), {
  family: "Open Sans",
});

function getDateInFilename(filename) {
  const datePattern = /\d{4}-\d{2}-\d{2}/;
  const match = filename.match(datePattern);
  return match ? match[0] : null;
}

function getTimeInFilename(filename) {
  const time = filename.split("_")[2];
  return time ? time.split('.')[0] + ":" + time.split('.')[1] : null;
}

async function getImageDate(filename, imageInput) {
  try {
    const filePath = path.join(imageInput, filename);
    const hasDateInName = /\d{4}-\d{2}-\d{2}/.test(filename);
    let dateFromFilename = null;
    let timeFromFilename = null;

    if (hasDateInName) {
      dateFromFilename = getDateInFilename(filename);
      timeFromFilename = getTimeInFilename(filename);
    }

    if (dateFromFilename && timeFromFilename) {
      return `${dateFromFilename} ${timeFromFilename}`;
    }

    const tags = await exiftool.exiftool.read(filePath);
    if (tags?.DateTimeOriginal?.rawValue) {
      const [dateOnly, timeFull] = tags.DateTimeOriginal.rawValue.split(" ");
      const timeOnly = timeFull?.slice(0, 5);
      const [year, month, day] = dateOnly.split(":");
      return `${year}-${month}-${day} ${timeOnly}`;
    }

    const stats = await fs.promises.stat(filePath);
    const mtime = stats.mtime;
    return `${mtime.getFullYear()}-${String(mtime.getMonth() + 1).padStart(2, "0")}-${String(mtime.getDate()).padStart(2, "0")} ${String(mtime.getHours()).padStart(2, "0")}:${String(mtime.getMinutes()).padStart(2, "0")}`;
  } catch (err) {
    console.error("Failed to read EXIF:", err);
  }
}

async function addWatermark(filename, buffer, watermarkText) {
  const image = await loadImage(buffer);
  const canvas = createCanvas(image.width, image.height);
  const ctx = canvas.getContext("2d");

  // Draw the original image
  ctx.drawImage(image, 0, 0);

  // Watermark styles
  ctx.font = "32px 'Open Sans'";
  ctx.fillStyle = "rgba(255, 255, 255, 0.8)";
  ctx.textAlign = "right";
  ctx.textBaseline = "bottom";

  // Draw the watermark
  ctx.fillText(watermarkText, image.width - 10, image.height - 10);

  return canvas.toBuffer("image/jpeg");
}

async function watermarkAllImages(bufferMap, imageInput) {
  const outputMap = {};
  for (const [filename, buffer] of Object.entries(bufferMap)) {
    const watermarkText = await getImageDate(filename, imageInput);
    const watermarkedBuffer = await addWatermark(filename, buffer, watermarkText);
    outputMap[filename] = watermarkedBuffer;
  }
  return outputMap;
}

module.exports = {
  watermarkAllImages,
};