/**
 * Blog API functions
 */

import { apiRequest } from '../utils/api';
import type {
  UploadPresignedURLResponse,
  DownloadPresignedURLResponse,
  CreatePostResponse,
} from './types';

const API_BASE = '/api/blog';

/**
 * Get presigned URL for file upload
 */
export async function getUploadPresignedURL(fileName: string): Promise<UploadPresignedURLResponse> {
  const response = await apiRequest(`${API_BASE}/file/upload`, {
    method: 'POST',
    body: JSON.stringify({ fileName }),
  });

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

  return response.json();
}

/**
 * Get presigned URL for file download
 */
export async function getDownloadPresignedURL(fileKey: string): Promise<DownloadPresignedURLResponse> {
  const response = await apiRequest(`${API_BASE}/file/download`, {
    method: 'POST',
    body: JSON.stringify({ fileKey }),
  });

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

  return response.json();
}

/**
 * Upload file to S3 using presigned URL
 */
export async function uploadFileToS3(
  url: string,
  file: File,
  onProgress?: (progress: number) => void
): Promise<void> {
  return new Promise((resolve, reject) => {
    const xhr = new XMLHttpRequest();

    // Track upload progress
    xhr.upload.addEventListener('progress', (event) => {
      if (event.lengthComputable && onProgress) {
        const progress = (event.loaded / event.total) * 100;
        onProgress(progress);
      }
    });

    xhr.addEventListener('load', () => {
      if (xhr.status >= 200 && xhr.status < 300) {
        resolve();
      } else {
        reject(new Error(`Upload failed with status ${xhr.status}`));
      }
    });

    xhr.addEventListener('error', () => {
      reject(new Error('Upload failed'));
    });

    xhr.addEventListener('abort', () => {
      reject(new Error('Upload aborted'));
    });

    xhr.open('PUT', url);
    xhr.setRequestHeader('Content-Type', file.type);
    xhr.send(file);
  });
}

/**
 * Complete image upload workflow
 */
export async function uploadImage(
  file: File,
  onProgress?: (progress: number) => void
): Promise<{ fileKey: string; url: string }> {
  // Step 1: Get presigned URL
  const { url: uploadUrl, fileKey } = await getUploadPresignedURL(file.name);

  // Step 2: Upload file to S3
  await uploadFileToS3(uploadUrl, file, onProgress);

  // Step 3: Get download URL
  const { url: downloadUrl } = await getDownloadPresignedURL(fileKey);

  return { fileKey, url: downloadUrl };
}

/**
 * Create a new blog post
 */
export async function createBlogPost(
  title: string,
  content: string,
  coverImageKey: string
): Promise<CreatePostResponse> {
  const response = await apiRequest(`${API_BASE}/post/create`, {
    method: 'POST',
    body: JSON.stringify({
      title,
      content,
      coverImageKey,
    }),
  });

  if (!response.ok) {
    throw new Error(`Failed to create post: ${response.statusText}`);
  }

  return response.json();
}