next-chat/app/utils/chat.ts

import { CACHE_URL_PREFIX, UPLOAD_URL } from "@/app/constant";
import { RequestMessage } from "@/app/client/api";

export function compressImage(file: Blob, maxSize: number): Promise<string> {
  return new Promise((resolve, reject) => {
    const reader = new FileReader();
    reader.onload = (readerEvent: any) => {
      const image = new Image();
      image.onload = () => {
        let canvas = document.createElement("canvas");
        let ctx = canvas.getContext("2d");
        let width = image.width;
        let height = image.height;
        let quality = 0.9;
        let dataUrl;

        do {
          canvas.width = width;
          canvas.height = height;
          ctx?.clearRect(0, 0, canvas.width, canvas.height);
          ctx?.drawImage(image, 0, 0, width, height);
          dataUrl = canvas.toDataURL("image/jpeg", quality);

          if (dataUrl.length < maxSize) break;

          if (quality > 0.5) {
            // Prioritize quality reduction
            quality -= 0.1;
          } else {
            // Then reduce the size
            width *= 0.9;
            height *= 0.9;
          }
        } while (dataUrl.length > maxSize);

        resolve(dataUrl);
      };
      image.onerror = reject;
      image.src = readerEvent.target.result;
    };
    reader.onerror = reject;

    if (file.type.includes("heic")) {
      try {
        const heic2any = require("heic2any");
        heic2any({ blob: file, toType: "image/jpeg" })
          .then((blob: Blob) => {
            reader.readAsDataURL(blob);
          })
          .catch((e: any) => {
            reject(e);
          });
      } catch (e) {
        reject(e);
      }
    }

    reader.readAsDataURL(file);
  });
}

export async function preProcessImageContent(
  content: RequestMessage["content"],
) {
  if (typeof content === "string") {
    return content;
  }
  const result = [];
  for (const part of content) {
    if (part?.type == "image_url" && part?.image_url?.url) {
      try {
        const url = await cacheImageToBase64Image(part?.image_url?.url);
        result.push({ type: part.type, image_url: { url } });
      } catch (error) {
        console.error("Error processing image URL:", error);
      }
    } else {
      result.push({ ...part });
    }
  }
  return result;
}

const imageCaches: Record<string, string> = {};
export function cacheImageToBase64Image(imageUrl: string) {
  if (imageUrl.includes(CACHE_URL_PREFIX)) {
    if (!imageCaches[imageUrl]) {
      const reader = new FileReader();
      return fetch(imageUrl, {
        method: "GET",
        mode: "cors",
        credentials: "include",
      })
        .then((res) => res.blob())
        .then(
          async (blob) =>
            (imageCaches[imageUrl] = await compressImage(blob, 256 * 1024)),
        ); // compressImage
    }
    return Promise.resolve(imageCaches[imageUrl]);
  }
  return Promise.resolve(imageUrl);
}

export function base64Image2Blob(base64Data: string, contentType: string) {
  const byteCharacters = atob(base64Data);
  const byteNumbers = new Array(byteCharacters.length);
  for (let i = 0; i < byteCharacters.length; i++) {
    byteNumbers[i] = byteCharacters.charCodeAt(i);
  }
  const byteArray = new Uint8Array(byteNumbers);
  return new Blob([byteArray], { type: contentType });
}

export function uploadImage(file: Blob): Promise<string> {
  if (!window._SW_ENABLED) {
    // if serviceWorker register error, using compressImage
    return compressImage(file, 256 * 1024);
  }
  const body = new FormData();
  body.append("file", file);
  return fetch(UPLOAD_URL, {
    method: "post",
    body,
    mode: "cors",
    credentials: "include",
  })
    .then((res) => res.json())
    .then((res) => {
      console.log("res", res);
      if (res?.code == 0 && res?.data) {
        return res?.data;
      }
      throw Error(`upload Error: ${res?.msg}`);
    });
}

export function removeImage(imageUrl: string) {
  return fetch(imageUrl, {
    method: "DELETE",
    mode: "cors",
    credentials: "include",
  });
}