import type { CompressedImage, ImageFormat, UploadImageRequest, UploadImageResponse } from "~/types/image";
import { API_URLS } from "@/utils/api";

export class ImageUploadService {
  static async getUploadCredentials(
    _fileExtension: ImageFormat
  ): Promise<UploadImageResponse> {
    const request: UploadImageRequest = {
      file_extension: _fileExtension,
      expires_in: 3600,
      content_length_range: {
        min_bytes: 1024,
        max_bytes: 10485760
      }
    };
    const response = await fetch(API_URLS.getUploadUrl, {
      method: "POST",
      headers: {
        Accept: "application/json",
        "Content-Type": "application/json"
      },
      body: JSON.stringify({ data: request })
    });

    if (!response.ok) {
      throw new Error(
        `Failed to get upload credentials: ${response.status} ${response.statusText}`
      );
    }

    return await response.json();
  }
  static async compressImage(
    file: File,
    maxWidth = 1024,
    quality = 0.8
  ): Promise<CompressedImage> {
    return new Promise((resolve) => {
      const canvas = document.createElement("canvas");
      const ctx = canvas.getContext("2d")!;
      const img = new Image();

      img.onload = () => {
        const { width, height } = this.calculateDimensions(
          img.width,
          img.height,
          maxWidth
        );

        canvas.width = width;
        canvas.height = height;
        ctx.drawImage(img, 0, 0, width, height);
        canvas.toBlob(
          (blob) => {
            const compressedFile = new File([blob!], file.name, {
              type: "image/jpeg",
              lastModified: Date.now()
            });

            resolve({
              file: compressedFile,
              preview: canvas.toDataURL("image/jpeg", quality),
              format: "jpeg" as ImageFormat
            });
          },
          "image/jpeg",
          quality
        );
      };

      img.src = URL.createObjectURL(file);
    });
  }
  static getFileExtension(file: File): ImageFormat {
    const extension = file.name.split(".").pop()?.toLowerCase();

    switch (extension) {
      case "jpg":
      case "jpeg":
        return "jpeg";
      case "webp":
        return "webp";
      case "png":
        return "png";
      case "heic":
        return "heic";
      default:
        return "jpeg";
    }
  }
  static calculateDimensions(
    originalWidth: number,
    originalHeight: number,
    maxWidth: number
  ) {
    if (originalWidth <= maxWidth) {
      return { width: originalWidth, height: originalHeight };
    }

    const ratio = originalHeight / originalWidth;

    return {
      width: maxWidth,
      height: Math.round(maxWidth * ratio)
    };
  }
  static async uploadImage(
    credentials: UploadImageResponse,
    file: File
  ): Promise<string> {
    const formData = new FormData();

    Object.entries(credentials.fields).forEach(([key, value]) => {
      formData.append(key, value);
    });
    formData.append("file", file);

    const response = await fetch(credentials.url, {
      method: "POST",
      body: formData
    });

    if (!response.ok && response.status !== 204) {
      throw new Error(`خطا در آپلود تصویر`);
    }

    return credentials.public_url;
  }
}