/**
 * Image Storage Utility
 *
 * Downloads and stores product images to MinIO/S3 with proper hierarchy.
 * Images are downloaded ONCE on first discovery/refresh, then served from our CDN.
 *
 * Storage structure in MinIO:
 *   cannaiq/images/products/<state>/<store_slug>/<brand_slug>/<product_id>/image-<hash>.webp
 *   cannaiq/images/brands/<brand_slug>/logo.webp
 *
 * Public URL format:
 *   https://cdn.cannabrands.app/cannaiq/images/products/az/store/brand/123/image-abc123.webp
 */

import axios from 'axios';
// @ts-ignore - sharp module typing quirk
const sharp = require('sharp');
import { createHash } from 'crypto';
import * as Minio from 'minio';

// MinIO configuration
const MINIO_ENDPOINT = process.env.MINIO_ENDPOINT || 'cdn.cannabrands.app';
const MINIO_PORT = parseInt(process.env.MINIO_PORT || '443');
const MINIO_USE_SSL = process.env.MINIO_USE_SSL !== 'false';
const MINIO_ACCESS_KEY = process.env.MINIO_ACCESS_KEY;
const MINIO_SECRET_KEY = process.env.MINIO_SECRET_KEY;
const MINIO_BUCKET = process.env.MINIO_BUCKET || 'cannaiq';
const MINIO_PUBLIC_URL = process.env.MINIO_PUBLIC_ENDPOINT || 'https://cdn.cannabrands.app';

// Check if MinIO is configured
const useMinIO = !!(MINIO_ENDPOINT && MINIO_ACCESS_KEY && MINIO_SECRET_KEY);

let minioClient: Minio.Client | null = null;

function getMinioClient(): Minio.Client | null {
  if (!useMinIO) return null;

  if (!minioClient) {
    minioClient = new Minio.Client({
      endPoint: MINIO_ENDPOINT,
      port: MINIO_PORT,
      useSSL: MINIO_USE_SSL,
      accessKey: MINIO_ACCESS_KEY!,
      secretKey: MINIO_SECRET_KEY!,
    });
  }
  return minioClient;
}

export interface LocalImageSizes {
  original: string;   // URL path to original image
  full: string;
  medium: string;
  thumb: string;
}

export interface DownloadResult {
  success: boolean;
  urls?: LocalImageSizes;
  localPaths?: LocalImageSizes;
  error?: string;
  bytesDownloaded?: number;
  skipped?: boolean;  // True if image already exists
}

export interface ProductImageContext {
  stateCode: string;      // e.g., "AZ", "CA"
  storeSlug: string;      // e.g., "deeply-rooted"
  brandSlug: string;      // e.g., "high-west-farms"
  productId: string;      // External product ID
  dispensaryId?: number;  // For backwards compat
}

/**
 * Sanitize a string for use in file paths
 */
function slugify(str: string): string {
  return str
    .toLowerCase()
    .replace(/[^a-z0-9]+/g, '-')
    .replace(/^-+|-+$/g, '')
    .substring(0, 50) || 'unknown';
}

/**
 * Generate a short hash from a URL for deduplication
 */
function hashUrl(url: string): string {
  return createHash('md5').update(url).digest('hex').substring(0, 8);
}

/**
 * Build the MinIO object key for a product image
 * Structure: images/products/<state>/<store>/<brand>/<product>/image-<hash>.webp
 */
function buildImageKey(ctx: ProductImageContext, urlHash: string): string {
  const state = slugify(ctx.stateCode || 'unknown');
  const store = slugify(ctx.storeSlug || 'unknown');
  const brand = slugify(ctx.brandSlug || 'unknown');
  const product = slugify(ctx.productId || 'unknown');

  return `images/products/${state}/${store}/${brand}/${product}/image-${urlHash}.webp`;
}

/**
 * Convert MinIO object key to public URL
 */
function keyToUrl(key: string): string {
  return `${MINIO_PUBLIC_URL}/${MINIO_BUCKET}/${key}`;
}

/**
 * Download an image from a URL and return the buffer
 */
async function downloadImage(imageUrl: string): Promise<Buffer> {
  const response = await axios.get(imageUrl, {
    responseType: 'arraybuffer',
    timeout: 30000,
    headers: {
      'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36',
      'Accept': 'image/webp,image/apng,image/*,*/*;q=0.8',
    },
  });
  return Buffer.from(response.data);
}

/**
 * Check if an image already exists in MinIO
 */
async function imageExistsInMinIO(key: string): Promise<boolean> {
  const client = getMinioClient();
  if (!client) return false;

  try {
    await client.statObject(MINIO_BUCKET, key);
    return true;
  } catch (error: any) {
    if (error.code === 'NotFound') return false;
    // For other errors, assume it doesn't exist
    return false;
  }
}

/**
 * Upload image buffer to MinIO
 */
async function uploadToMinIO(buffer: Buffer, key: string): Promise<void> {
  const client = getMinioClient();
  if (!client) {
    throw new Error('MinIO not configured');
  }

  await client.putObject(MINIO_BUCKET, key, buffer, buffer.length, {
    'Content-Type': 'image/webp',
  });
}

/**
 * Download and store a product image
 *
 * @param imageUrl - The source image URL (e.g., from Dutchie CDN)
 * @param ctx - Product context (state, store, brand, product)
 * @param options - Download options
 * @returns Download result with our CDN URLs
 */
export async function downloadProductImage(
  imageUrl: string,
  ctx: ProductImageContext,
  options: { skipIfExists?: boolean } = {}
): Promise<DownloadResult> {
  const { skipIfExists = true } = options;

  try {
    if (!imageUrl) {
      return { success: false, error: 'No image URL provided' };
    }

    if (!useMinIO) {
      return { success: false, error: 'MinIO not configured - images require MinIO storage' };
    }

    const urlHash = hashUrl(imageUrl);
    const key = buildImageKey(ctx, urlHash);

    // Check if image already exists in MinIO
    if (skipIfExists) {
      const exists = await imageExistsInMinIO(key);
      if (exists) {
        const url = keyToUrl(key);
        return {
          success: true,
          skipped: true,
          urls: {
            original: url,
            full: url,
            medium: url,
            thumb: url,
          },
          localPaths: {
            original: key,
            full: key,
            medium: key,
            thumb: key,
          },
        };
      }
    }

    // Download the image from source (e.g., Dutchie CDN)
    const buffer = await downloadImage(imageUrl);

    // Convert to webp for consistency and compression
    const webpBuffer = await sharp(buffer)
      .webp({ quality: 90 })
      .toBuffer();

    // Upload to MinIO
    await uploadToMinIO(webpBuffer, key);

    const url = keyToUrl(key);

    return {
      success: true,
      urls: {
        original: url,
        full: url,
        medium: url,
        thumb: url,
      },
      localPaths: {
        original: key,
        full: key,
        medium: key,
        thumb: key,
      },
      bytesDownloaded: webpBuffer.length,
    };
  } catch (error: any) {
    return {
      success: false,
      error: error.message || 'Unknown error',
    };
  }
}

/**
 * Download a brand logo
 */
export async function downloadBrandLogo(
  imageUrl: string,
  brandSlug: string,
  options: { skipIfExists?: boolean } = {}
): Promise<DownloadResult> {
  const { skipIfExists = true } = options;

  try {
    if (!imageUrl) {
      return { success: false, error: 'No image URL provided' };
    }

    if (!useMinIO) {
      return { success: false, error: 'MinIO not configured - images require MinIO storage' };
    }

    const slug = slugify(brandSlug);
    const key = `images/brands/${slug}/logo.webp`;

    // Check if logo already exists
    if (skipIfExists) {
      const exists = await imageExistsInMinIO(key);
      if (exists) {
        const url = keyToUrl(key);
        return {
          success: true,
          skipped: true,
          urls: {
            original: url,
            full: url,
            medium: url,
            thumb: url,
          },
        };
      }
    }

    // Download and process
    const buffer = await downloadImage(imageUrl);
    const webpBuffer = await sharp(buffer)
      .webp({ quality: 90 })
      .toBuffer();

    // Upload to MinIO
    await uploadToMinIO(webpBuffer, key);

    const url = keyToUrl(key);

    return {
      success: true,
      urls: {
        original: url,
        full: url,
        medium: url,
        thumb: url,
      },
      bytesDownloaded: webpBuffer.length,
    };
  } catch (error: any) {
    return {
      success: false,
      error: error.message || 'Unknown error',
    };
  }
}

/**
 * Check if a product image already exists
 */
export async function productImageExists(
  imageUrl: string,
  ctx: ProductImageContext
): Promise<boolean> {
  if (!useMinIO) return false;

  const urlHash = hashUrl(imageUrl);
  const key = buildImageKey(ctx, urlHash);
  return imageExistsInMinIO(key);
}

// Track whether image storage is available
let imageStorageReady = false;

export function isImageStorageReady(): boolean {
  return imageStorageReady;
}

/**
 * Initialize image storage
 */
export async function initializeImageStorage(): Promise<void> {
  if (!useMinIO) {
    console.warn('[ImageStorage] MinIO not configured (MINIO_ENDPOINT/ACCESS_KEY/SECRET_KEY required)');
    console.warn('[ImageStorage] Image downloads will be disabled');
    imageStorageReady = false;
    return;
  }

  try {
    const client = getMinioClient();
    if (!client) {
      throw new Error('Failed to create MinIO client');
    }

    // Verify bucket exists and is accessible
    const exists = await client.bucketExists(MINIO_BUCKET);
    if (!exists) {
      console.warn(`[ImageStorage] Bucket ${MINIO_BUCKET} does not exist`);
      imageStorageReady = false;
      return;
    }

    console.log(`[ImageStorage] Initialized with MinIO: ${MINIO_ENDPOINT}/${MINIO_BUCKET}`);
    console.log(`[ImageStorage] Public URL: ${MINIO_PUBLIC_URL}/${MINIO_BUCKET}/images/...`);
    imageStorageReady = true;
  } catch (error: any) {
    console.warn(`[ImageStorage] WARNING: Could not initialize MinIO: ${error.message}`);
    console.warn('[ImageStorage] Image downloads will be disabled');
    imageStorageReady = false;
  }
}

/**
 * Get storage stats (placeholder - would need to list objects)
 */
export async function getStorageStats(): Promise<{
  basePath: string;
  productCount: number;
  brandCount: number;
  totalSizeBytes: number;
}> {
  return {
    basePath: `${MINIO_ENDPOINT}/${MINIO_BUCKET}/images`,
    productCount: 0,  // Would need to list objects
    brandCount: 0,
    totalSizeBytes: 0,
  };
}