memer/backend/src/services/image.ts

import sharp from 'sharp';
import fs from 'fs';
import { absolutePath, ensureDir } from './storage.js';

export interface ImageMeta {
  width: number;
  height: number;
  mimeType: string;
  size: number;
}

export async function extractMeta(filePath: string): Promise<ImageMeta> {
  const abs = absolutePath(filePath);
  const meta = await sharp(abs).metadata();
  const stat = fs.statSync(abs);

  const mimeMap: Record<string, string> = {
    jpeg: 'image/jpeg',
    png: 'image/png',
    gif: 'image/gif',
    webp: 'image/webp',
  };

  return {
    width: meta.width ?? 0,
    height: meta.height ?? 0,
    mimeType: mimeMap[meta.format ?? ''] ?? 'image/jpeg',
    size: stat.size,
  };
}

export async function saveBuffer(buffer: Buffer, destRelPath: string): Promise<void> {
  ensureDir(destRelPath);
  const abs = absolutePath(destRelPath);
  fs.writeFileSync(abs, buffer);
}

export interface ResizeOptions {
  width?: number;
  height?: number;
  quality?: number;
}

export async function resizeImage(
  srcRelPath: string,
  destRelPath: string,
  options: ResizeOptions
): Promise<ImageMeta> {
  const srcAbs = absolutePath(srcRelPath);
  ensureDir(destRelPath);
  const destAbs = absolutePath(destRelPath);

  const src = await sharp(srcAbs).metadata();
  const isGif = src.format === 'gif';

  let pipeline = sharp(srcAbs, { animated: isGif });

  if (options.width || options.height) {
    pipeline = pipeline.resize({
      width: options.width,
      height: options.height,
      fit: 'inside',
      withoutEnlargement: true,
    });
  }

  if (!isGif && options.quality) {
    if (src.format === 'jpeg') pipeline = pipeline.jpeg({ quality: options.quality });
    else if (src.format === 'png') pipeline = pipeline.png({ quality: options.quality });
    else if (src.format === 'webp') pipeline = pipeline.webp({ quality: options.quality });
  }

  await pipeline.toFile(destAbs);

  const resultMeta = await sharp(destAbs).metadata();
  const stat = fs.statSync(destAbs);

  const mimeMap: Record<string, string> = {
    jpeg: 'image/jpeg',
    png: 'image/png',
    gif: 'image/gif',
    webp: 'image/webp',
  };

  return {
    width: resultMeta.width ?? 0,
    height: resultMeta.height ?? 0,
    mimeType: mimeMap[resultMeta.format ?? ''] ?? 'image/jpeg',
    size: stat.size,
  };
}