'use server';
/**
 * @fileOverview An AI agent for summarizing documents.
 *
 * - summarizeDocument - A function that handles the document summarization process.
 * - AiDocumentSummarizationInput - The input type for the summarizeDocument function.
 * - AiDocumentSummarizationOutput - The return type for the summarizeDocument function.
 */

import { ai } from '@/ai/genkit';
import { z } from 'genkit';
import pdf from 'pdf-parse';

const AiDocumentSummarizationInputSchema = z.object({
  fileContentBase64: z.string().describe('The file content as a base64 encoded string.'),
  mimeType: z.string().describe('The mime type of the file.'),
});
export type AiDocumentSummarizationInput = z.infer<typeof AiDocumentSummarizationInputSchema>;

const AiDocumentSummarizationOutputSchema = z.object({
  summary: z.string().describe('A concise and accurate summary of the document.'),
  documentContent: z.string().describe('The extracted text content of the document.'),
});
export type AiDocumentSummarizationOutput = z.infer<typeof AiDocumentSummarizationOutputSchema>;

export async function summarizeDocument(
  input: AiDocumentSummarizationInput
): Promise<AiDocumentSummarizationOutput> {
  return aiDocumentSummarizationFlow(input);
}

const PromptInputSchema = z.object({
  documentContent: z.string().describe('The full text content of the document to be summarized.'),
});

const PromptOutputSchema = z.object({
  summary: z.string().describe('A concise and accurate summary of the document.'),
});

const aiDocumentSummarizationPrompt = ai.definePrompt({
  name: 'aiDocumentSummarizationPrompt',
  input: { schema: PromptInputSchema },
  output: { schema: PromptOutputSchema },
  prompt: `You are an AI assistant specialized in summarizing documents. Your goal is to provide a concise and accurate summary of the given document, highlighting its main points and key information. The summary should be easy to understand and capture the essence of the document.

Document Content:
{{{
documentContent
}}}`,
});

const aiDocumentSummarizationFlow = ai.defineFlow(
  {
    name: 'aiDocumentSummarizationFlow',
    inputSchema: AiDocumentSummarizationInputSchema,
    outputSchema: AiDocumentSummarizationOutputSchema,
  },
  async (input) => {
    let documentContent: string;
    const fileBuffer = Buffer.from(input.fileContentBase64, 'base64');

    if (input.mimeType === 'application/pdf') {
      try {
        const data = await pdf(fileBuffer);
        documentContent = data.text;
      } catch (e) {
        console.error('Error parsing PDF', e);
        return { summary: 'Failed to parse the PDF document.', documentContent: 'Could not read PDF content.' };
      }
    } else {
      documentContent = fileBuffer.toString('utf-8');
    }

    if (!documentContent.trim()) {
      return { summary: 'The document appears to be empty or could not be read.', documentContent };
    }

    const { output } = await aiDocumentSummarizationPrompt({ documentContent });
    return { summary: output!.summary, documentContent };
  }
);