서버, 클라이언트, 서비스 워커 공용 코드를 lib/shared로 분리하고 브라우저 전용 모듈을 lib/client로 재구성

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/lib/client/media/exif.ts

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+import ExifReader from "exifreader";
+
+export const extractExifDateTime = (fileBuffer: ArrayBuffer) => {
+  const exif = ExifReader.load(fileBuffer);
+  const dateTimeOriginal = exif["DateTimeOriginal"]?.description;
+  const offsetTimeOriginal = exif["OffsetTimeOriginal"]?.description;
+  if (!dateTimeOriginal) return undefined;
+
+  const [date, time] = dateTimeOriginal.split(" ");
+  if (!date || !time) return undefined;
+
+  const [year, month, day] = date.split(":").map(Number);
+  const [hour, minute, second] = time.split(":").map(Number);
+  if (!year || !month || !day || !hour || !minute || !second) return undefined;
+
+  if (!offsetTimeOriginal) {
+    // No timezone information.. Assume local timezone
+    return new Date(year, month - 1, day, hour, minute, second);
+  }
+
+  const offsetSign = offsetTimeOriginal[0] === "+" ? 1 : -1;
+  const [offsetHour, offsetMinute] = offsetTimeOriginal.slice(1).split(":").map(Number);
+
+  const utcDate = Date.UTC(year, month - 1, day, hour, minute, second);
+  const offsetMs = offsetSign * ((offsetHour ?? 0) * 60 + (offsetMinute ?? 0)) * 60 * 1000;
+  return new Date(utcDate - offsetMs);
+};

src/lib/client/media/thumbnail.ts

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+import { encodeToBase64 } from "#lib/shared/crypto/index.js";
+
+const scaleSize = (width: number, height: number, targetSize: number) => {
+  if (width <= targetSize || height <= targetSize) {
+    return { width, height };
+  }
+
+  const scale = targetSize / Math.min(width, height);
+  return {
+    width: Math.round(width * scale),
+    height: Math.round(height * scale),
+  };
+};
+
+const capture = (
+  width: number,
+  height: number,
+  drawer: (context: CanvasRenderingContext2D, width: number, height: number) => void,
+  targetSize = 250,
+) => {
+  return new Promise<Blob>((resolve, reject) => {
+    const canvas = document.createElement("canvas");
+    const { width: scaledWidth, height: scaledHeight } = scaleSize(width, height, targetSize);
+
+    canvas.width = scaledWidth;
+    canvas.height = scaledHeight;
+
+    const context = canvas.getContext("2d");
+    if (!context) {
+      return reject(new Error("Failed to generate thumbnail"));
+    }
+
+    drawer(context, scaledWidth, scaledHeight);
+    canvas.toBlob((blob) => {
+      if (blob && blob.type === "image/webp") {
+        resolve(blob);
+      } else {
+        reject(new Error("Failed to generate thumbnail"));
+      }
+    }, "image/webp");
+  });
+};
+
+const generateImageThumbnail = (imageUrl: string) => {
+  return new Promise<Blob>((resolve, reject) => {
+    const image = new Image();
+    image.onload = () => {
+      capture(image.width, image.height, (context, width, height) => {
+        context.drawImage(image, 0, 0, width, height);
+      })
+        .then(resolve)
+        .catch(reject);
+    };
+    image.onerror = reject;
+    image.src = imageUrl;
+  });
+};
+
+export const captureVideoThumbnail = (video: HTMLVideoElement) => {
+  return capture(video.videoWidth, video.videoHeight, (context, width, height) => {
+    context.drawImage(video, 0, 0, width, height);
+  });
+};
+
+const generateVideoThumbnail = (videoUrl: string, time = 0) => {
+  return new Promise<Blob>((resolve, reject) => {
+    const video = document.createElement("video");
+    video.onloadedmetadata = () => {
+      if (video.videoWidth === 0 || video.videoHeight === 0) {
+        return reject();
+      }
+
+      const callbackId = video.requestVideoFrameCallback(() => {
+        captureVideoThumbnail(video).then(resolve).catch(reject);
+        video.cancelVideoFrameCallback(callbackId);
+      });
+      video.currentTime = Math.min(time, video.duration);
+    };
+    video.onerror = reject;
+
+    video.muted = true;
+    video.playsInline = true;
+    video.src = videoUrl;
+  });
+};
+
+export const generateThumbnail = async (blob: Blob) => {
+  let url;
+  try {
+    if (blob.type.startsWith("image/")) {
+      url = URL.createObjectURL(blob);
+      try {
+        return await generateImageThumbnail(url);
+      } catch {
+        URL.revokeObjectURL(url);
+        url = undefined;
+
+        if (blob.type === "image/heic") {
+          const { default: heic2any } = await import("heic2any");
+          url = URL.createObjectURL((await heic2any({ blob, toType: "image/png" })) as Blob);
+          return await generateImageThumbnail(url);
+        } else {
+          return null;
+        }
+      }
+    } else if (blob.type.startsWith("video/")) {
+      url = URL.createObjectURL(blob);
+      return await generateVideoThumbnail(url);
+    }
+    return null;
+  } catch {
+    return null;
+  } finally {
+    if (url) {
+      URL.revokeObjectURL(url);
+    }
+  }
+};
+
+export const getThumbnailUrl = (thumbnailBuffer: ArrayBuffer) => {
+  return `data:image/webp;base64,${encodeToBase64(thumbnailBuffer)}`;
+};