// lib/deepgram.ts
import { createClient, DeepgramClient } from '@deepgram/sdk';

let client: DeepgramClient | null = null;

export function getDeepgramClient(): DeepgramClient {
  if (!client) {
    const apiKey = process.env.DEEPGRAM_API_KEY;
    if (!apiKey) {
      throw new Error('DEEPGRAM_API_KEY environment variable not set');
    }
    client = createClient(apiKey);
  }
  return client;
}

export function resetClient(): void {
  client = null;
}

// types/deepgram.ts
export interface TranscriptWord {
  word: string;
  start: number;
  end: number;
  confidence: number;
  punctuated_word?: string;
}

export interface TranscriptAlternative {
  transcript: string;
  confidence: number;
  words: TranscriptWord[];
}

export interface TranscriptChannel {
  alternatives: TranscriptAlternative[];
}

export interface TranscriptResult {
  results: {
    channels: TranscriptChannel[];
    utterances?: Array<{
      start: number;
      end: number;
      transcript: string;
      speaker: number;
    }>;
  };
  metadata: {
    request_id: string;
    model_uuid: string;
    model_info: Record<string, unknown>;
  };
}

// lib/transcribe.ts
import { getDeepgramClient } from './deepgram';
import { TranscriptResult } from '../types/deepgram';

export class TranscriptionError extends Error {
  constructor(
    message: string,
    public readonly code: string,
    public readonly requestId?: string
  ) {
    super(message);
    this.name = 'TranscriptionError';
  }
}

export async function transcribeUrl(
  url: string,
  options: { model?: string; language?: string } = {}
): Promise<TranscriptResult> {
  const client = getDeepgramClient();

  try {
    const { result, error } = await client.listen.prerecorded.transcribeUrl(
      { url },
      {
        model: options.model || 'nova-2',
        language: options.language || 'en',
        smart_format: true,
        punctuate: true,
      }
    );

    if (error) {
      throw new TranscriptionError(
        error.message || 'Transcription failed',
        error.code || 'UNKNOWN_ERROR'
      );
    }

    return result as TranscriptResult;
  } catch (err) {
    if (err instanceof TranscriptionError) throw err;
    throw new TranscriptionError(
      err instanceof Error ? err.message : 'Unknown error',
      'NETWORK_ERROR'
    );
  }
}

// lib/retry.ts
interface RetryOptions {
  maxRetries?: number;
  baseDelay?: number;
  maxDelay?: number;
}

export async function withRetry<T>(
  fn: () => Promise<T>,
  options: RetryOptions = {}
): Promise<T> {
  const { maxRetries = 3, baseDelay = 1000, maxDelay = 10000 } = options;

  let lastError: Error | undefined;

  for (let attempt = 0; attempt <= maxRetries; attempt++) {
    try {
      return await fn();
    } catch (error) {
      lastError = error instanceof Error ? error : new Error(String(error));

      // Don't retry on auth errors
      if (lastError.message.includes('401') ||
          lastError.message.includes('403')) {
        throw lastError;
      }

      if (attempt < maxRetries) {
        const delay = Math.min(baseDelay * Math.pow(2, attempt), maxDelay);
        await new Promise(resolve => setTimeout(resolve, delay));
      }
    }
  }

  throw lastError;
}

// Usage
const result = await withRetry(() => transcribeUrl(audioUrl));

# lib/deepgram_client.py
from deepgram import DeepgramClient, PrerecordedOptions
from functools import lru_cache
import os

@lru_cache(maxsize=1)
def get_deepgram_client() -> DeepgramClient:
    """Get or create Deepgram client singleton."""
    api_key = os.environ.get('DEEPGRAM_API_KEY')
    if not api_key:
        raise ValueError('DEEPGRAM_API_KEY environment variable not set')
    return DeepgramClient(api_key)

def transcribe_url(url: str, model: str = 'nova-2') -> dict:
    """Transcribe audio from URL with error handling."""
    client = get_deepgram_client()

    options = PrerecordedOptions(
        model=model,
        smart_format=True,
        punctuate=True,
    )

    try:
        response = client.listen.rest.v("1").transcribe_url(
            {"url": url},
            options
        )
        return response.to_dict()
    except Exception as e:
        raise TranscriptionError(str(e)) from e