/**
 * S3 Storage Provider for LocalGreenChain
 * Agent 3: File Upload & Storage System
 *
 * Compatible with AWS S3, Cloudflare R2, and MinIO
 */

import {
  S3Client,
  PutObjectCommand,
  DeleteObjectCommand,
  HeadObjectCommand,
  GetObjectCommand,
} from '@aws-sdk/client-s3';
import { getSignedUrl } from '@aws-sdk/s3-request-presigner';
import { StorageConfig, StorageProviderInterface } from '../types';

export class S3StorageProvider implements StorageProviderInterface {
  private client: S3Client;
  private bucket: string;
  private publicUrl?: string;

  constructor(config: StorageConfig) {
    this.bucket = config.bucket;
    this.publicUrl = config.publicUrl;

    const clientConfig: ConstructorParameters<typeof S3Client>[0] = {
      region: config.region || 'us-east-1',
    };

    // Add endpoint for R2/MinIO
    if (config.endpoint) {
      clientConfig.endpoint = config.endpoint;
      clientConfig.forcePathStyle = config.provider === 'minio';
    }

    // Add credentials if provided
    if (config.accessKeyId && config.secretAccessKey) {
      clientConfig.credentials = {
        accessKeyId: config.accessKeyId,
        secretAccessKey: config.secretAccessKey,
      };
    }

    this.client = new S3Client(clientConfig);
  }

  async upload(key: string, buffer: Buffer, contentType: string): Promise<string> {
    const command = new PutObjectCommand({
      Bucket: this.bucket,
      Key: key,
      Body: buffer,
      ContentType: contentType,
      CacheControl: 'public, max-age=31536000', // 1 year cache
    });

    await this.client.send(command);
    return this.getPublicUrl(key);
  }

  async delete(key: string): Promise<boolean> {
    try {
      const command = new DeleteObjectCommand({
        Bucket: this.bucket,
        Key: key,
      });

      await this.client.send(command);
      return true;
    } catch (error) {
      console.error('Error deleting file from S3:', error);
      return false;
    }
  }

  async getSignedUrl(key: string, expiresIn = 3600): Promise<string> {
    const command = new GetObjectCommand({
      Bucket: this.bucket,
      Key: key,
    });

    return getSignedUrl(this.client, command, { expiresIn });
  }

  async getPresignedUploadUrl(key: string, contentType: string, expiresIn = 3600): Promise<string> {
    const command = new PutObjectCommand({
      Bucket: this.bucket,
      Key: key,
      ContentType: contentType,
    });

    return getSignedUrl(this.client, command, { expiresIn });
  }

  async exists(key: string): Promise<boolean> {
    try {
      const command = new HeadObjectCommand({
        Bucket: this.bucket,
        Key: key,
      });

      await this.client.send(command);
      return true;
    } catch {
      return false;
    }
  }

  getPublicUrl(key: string): string {
    if (this.publicUrl) {
      return `${this.publicUrl}/${key}`;
    }
    return `https://${this.bucket}.s3.amazonaws.com/${key}`;
  }
}