package com.example.ppt2pdf.controller;

import org.springframework.http.HttpHeaders;
import org.springframework.http.MediaType;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.*;
import org.springframework.web.multipart.MultipartFile;
import org.springframework.beans.factory.annotation.Value;

import java.io.*;
import java.nio.file.*;
import java.util.UUID;

@RestController
@RequestMapping("/api")
@CrossOrigin(origins = "*")
public class ConvertController {

    @Value("${app.temp-dir:/tmp/ppt2pdf}")
    private String tempDir;

    @PostMapping("/convert")
    public ResponseEntity convertToPdf(@RequestParam("file") MultipartFile file) {
        if (file.isEmpty()) {
            return ResponseEntity.badRequest().body("No file uploaded".getBytes());
        }

        String originalFilename = file.getOriginalFilename();
        if (originalFilename == null || 
            (!originalFilename.toLowerCase().endsWith(".ppt") && 
             !originalFilename.toLowerCase().endsWith(".pptx"))) {
            return ResponseEntity.badRequest().body("Invalid file type. Please upload a PPT or PPTX file.".getBytes());
        }

        String sessionId = UUID.randomUUID().toString();
        Path workingDir = Paths.get(tempDir, sessionId);
        
        try {
            Files.createDirectories(workingDir);
            
            // Save uploaded file
            Path inputFile = workingDir.resolve(originalFilename);
            Files.copy(file.getInputStream(), inputFile, StandardCopyOption.REPLACE_EXISTING);
            
            // Convert using LibreOffice
            ProcessBuilder processBuilder = new ProcessBuilder(
                "soffice", 
                "--headless", 
                "--convert-to", 
                "pdf", 
                "--outdir", 
                workingDir.toString(),
                inputFile.toString()
            );
            
            Process process = processBuilder.start();
            int exitCode = process.waitFor();
            
            if (exitCode != 0) {
                throw new RuntimeException("LibreOffice conversion failed with exit code: " + exitCode);
            }
            
            // Find the converted PDF file
            String baseName = originalFilename.replaceFirst("[.][^.]+$", "");
            Path pdfFile = workingDir.resolve(baseName + ".pdf");
            
            if (!Files.exists(pdfFile)) {
                // Try to find any PDF file in the directory
                try (DirectoryStream stream = Files.newDirectoryStream(workingDir, "*.pdf")) {
                    for (Path entry : stream) {
                        pdfFile = entry;
                        break;
                    }
                }
                
                if (!Files.exists(pdfFile)) {
                    throw new RuntimeException("Converted PDF file not found");
                }
            }
            
            // Read the PDF file
            byte[] pdfBytes = Files.readAllBytes(pdfFile);
            
            // Set response headers
            HttpHeaders headers = new HttpHeaders();
            headers.setContentType(MediaType.APPLICATION_PDF);
            headers.setContentDispositionFormData("attachment", baseName + ".pdf");
            headers.setContentLength(pdfBytes.length);
            
            return ResponseEntity.ok()
                .headers(headers)
                .body(pdfBytes);
            
        } catch (Exception e) {
            return ResponseEntity.internalServerError()
                .body(("Conversion failed: " + e.getMessage()).getBytes());
        } finally {
            // Clean up temporary files
            try {
                deleteDirectory(workingDir.toFile());
            } catch (IOException e) {
                System.err.println("Failed to clean up temporary directory: " + e.getMessage());
            }
        }
    }
    
    private void deleteDirectory(File directory) throws IOException {
        if (directory.exists()) {
            File[] files = directory.listFiles();
            if (files != null) {
                for (File file : files) {
                    if (file.isDirectory()) {
                        deleteDirectory(file);
                    } else {
                        Files.deleteIfExists(file.toPath());
                    }
                }
            }
            Files.deleteIfExists(directory.toPath());
        }
    }
}

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>com.example</groupId>
  <artifactId>ppt2pdf</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <packaging>jar</packaging>
  <parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>3.1.4</version>
  </parent>
  <dependencies>
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-tomcat</artifactId>
    </dependency>
  </dependencies>
  <build>
    <plugins>
      <plugin>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-maven-plugin</artifactId>
      </plugin>
    </plugins>
  </build>
</project>

package com.example.ppt2pdf;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class Ppt2PdfApplication {
    public static void main(String[] args) {
        SpringApplication.run(Ppt2PdfApplication.class, args);
    }
}