/*
    * MIT License
    * Copyright (c) 2006-2025 JMockit developers
    * See LICENSE file for full license text.
    */
   package mockit.coverage;
   
   import edu.umd.cs.findbugs.annotations.NonNull;
   
  import java.io.File;
  import java.io.IOException;
  import java.nio.file.Path;
  import java.util.ArrayList;
  import java.util.List;
  
  import mockit.coverage.data.CoverageData;
  
  final class DataFileMerging {
      @NonNull
      private final List<File> inputFiles;
  
      DataFileMerging(@NonNull String[] inputPaths) {
          inputFiles = new ArrayList<>(inputPaths.length);
  
          for (String path : inputPaths) {
              addInputFileToList(path.trim());
          }
      }
  
      private void addInputFileToList(@NonNull String path) {
          if (!path.isEmpty()) {
              File inputFile = Path.of(path).toFile();
  
              if (inputFile.isDirectory()) {
                  inputFile = inputFile.toPath().resolve("coverage.ser").toFile();
              }
  
              inputFiles.add(inputFile);
          }
      }
  
      @NonNull
      CoverageData merge() throws IOException {
          CoverageData mergedData = null;
  
          for (File inputFile : inputFiles) {
              if (inputFile.exists()) {
                  CoverageData existingData = CoverageData.readDataFromFile(inputFile);
  
                  if (mergedData == null) {
                      mergedData = existingData;
                  } else {
                      mergedData.merge(existingData);
                  }
              }
          }
  
          if (mergedData == null) {
              throw new IllegalArgumentException("No input \"coverage.ser\" files found");
          }
  
          return mergedData;
      }
  }