ProxyAI/src/main/java/ee/carlrobert/codegpt/actions/GenerateGitCommitMessageAction.java

package ee.carlrobert.codegpt.actions;

import static com.intellij.openapi.ui.Messages.OK;
import static com.intellij.util.ObjectUtils.tryCast;
import static ee.carlrobert.codegpt.settings.service.ServiceType.YOU;
import static java.util.stream.Collectors.joining;

import com.intellij.notification.Notification;
import com.intellij.notification.NotificationType;
import com.intellij.notification.Notifications;
import com.intellij.openapi.actionSystem.ActionUpdateThread;
import com.intellij.openapi.actionSystem.AnAction;
import com.intellij.openapi.actionSystem.AnActionEvent;
import com.intellij.openapi.application.ApplicationManager;
import com.intellij.openapi.command.WriteCommandAction;
import com.intellij.openapi.editor.Document;
import com.intellij.openapi.editor.Editor;
import com.intellij.openapi.editor.ex.EditorEx;
import com.intellij.openapi.project.Project;
import com.intellij.openapi.vcs.FilePath;
import com.intellij.openapi.vcs.VcsDataKeys;
import com.intellij.openapi.vcs.ui.CommitMessage;
import com.intellij.vcs.commit.CommitWorkflowUi;
import ee.carlrobert.codegpt.CodeGPTBundle;
import ee.carlrobert.codegpt.EncodingManager;
import ee.carlrobert.codegpt.Icons;
import ee.carlrobert.codegpt.completions.CompletionRequestService;
import ee.carlrobert.codegpt.settings.GeneralSettings;
import ee.carlrobert.codegpt.ui.OverlayUtil;
import ee.carlrobert.llm.client.openai.completion.ErrorDetails;
import ee.carlrobert.llm.completion.CompletionEventListener;
import java.io.BufferedReader;
import java.io.File;
import java.io.IOException;
import java.io.InputStreamReader;
import java.nio.file.Files;
import java.nio.file.Path;
import java.util.AbstractMap;
import java.util.ArrayList;
import java.util.List;
import java.util.Objects;
import java.util.Optional;
import java.util.stream.Stream;
import okhttp3.sse.EventSource;
import org.jetbrains.annotations.NotNull;

public class GenerateGitCommitMessageAction extends AnAction {

  public static final int MAX_TOKEN_COUNT_WARNING = 4096;
  private final EncodingManager encodingManager;

  public GenerateGitCommitMessageAction() {
    super(
        CodeGPTBundle.get("action.generateCommitMessage.title"),
        CodeGPTBundle.get("action.generateCommitMessage.description"),
        Icons.Sparkle);
    encodingManager = EncodingManager.getInstance();
  }

  @Override
  public void update(@NotNull AnActionEvent event) {
    var commitWorkflowUi = event.getData(VcsDataKeys.COMMIT_WORKFLOW_UI);
    var selectedService = GeneralSettings.getCurrentState().getSelectedService();
    if (selectedService == YOU || commitWorkflowUi == null) {
      event.getPresentation().setVisible(false);
      return;
    }

    var callAllowed = CompletionRequestService.isRequestAllowed(
        GeneralSettings.getCurrentState().getSelectedService());
    event.getPresentation().setEnabled(callAllowed
        && new CommitWorkflowChanges(commitWorkflowUi).isFilesSelected());
    event.getPresentation().setText(CodeGPTBundle.get(callAllowed
        ? "action.generateCommitMessage.title"
        : "action.generateCommitMessage.missingCredentials"));
  }

  @Override
  public void actionPerformed(@NotNull AnActionEvent event) {
    var project = event.getProject();
    if (project == null || project.getBasePath() == null) {
      return;
    }

    var gitDiff = getGitDiff(event, project);
    var tokenCount = encodingManager.countTokens(gitDiff);
    if (tokenCount > MAX_TOKEN_COUNT_WARNING
        && OverlayUtil.showTokenSoftLimitWarningDialog(tokenCount) != OK) {
      return;
    }

    var editor = getCommitMessageEditor(event);
    if (editor != null) {
      ((EditorEx) editor).setCaretVisible(false);
      CompletionRequestService.getInstance()
          .generateCommitMessageAsync(gitDiff, getEventListener(project, editor.getDocument()));
    }
  }

  @Override
  public @NotNull ActionUpdateThread getActionUpdateThread() {
    return ActionUpdateThread.EDT;
  }

  private CompletionEventListener<String> getEventListener(Project project, Document document) {
    return new CompletionEventListener<>() {
      private final StringBuilder messageBuilder = new StringBuilder();

      @Override
      public void onMessage(String message, EventSource eventSource) {
        messageBuilder.append(message);
        var application = ApplicationManager.getApplication();
        application.invokeLater(() ->
            application.runWriteAction(() ->
                WriteCommandAction.runWriteCommandAction(project, () ->
                    document.setText(messageBuilder))));
      }

      @Override
      public void onError(ErrorDetails error, Throwable ex) {
        Notifications.Bus.notify(new Notification(
            "CodeGPT Notification Group",
            "CodeGPT",
            error.getMessage(),
            NotificationType.ERROR));
      }
    };
  }

  private Editor getCommitMessageEditor(AnActionEvent event) {
    var commitMessage = tryCast(
        event.getData(VcsDataKeys.COMMIT_MESSAGE_CONTROL),
        CommitMessage.class);
    return commitMessage != null ? commitMessage.getEditorField().getEditor() : null;
  }

  private String getGitDiff(AnActionEvent event, Project project) {
    var commitWorkflowUi = Optional.ofNullable(event.getData(VcsDataKeys.COMMIT_WORKFLOW_UI))
        .orElseThrow(() -> new IllegalStateException("Could not retrieve commit workflow ui."));
    var changes = new CommitWorkflowChanges(commitWorkflowUi);
    var projectBasePath = project.getBasePath();
    var gitDiff = getGitDiff(projectBasePath, changes.getIncludedVersionedFilePaths(), false);
    var stagedGitDiff = getGitDiff(projectBasePath, changes.getIncludedVersionedFilePaths(), true);
    var newFilesContent =
        getNewFilesDiff(projectBasePath, changes.getIncludedUnversionedFilePaths());

    return Stream.of(
            new AbstractMap.SimpleEntry<>("Git diff", gitDiff),
            new AbstractMap.SimpleEntry<>("Staged git diff", stagedGitDiff),
            new AbstractMap.SimpleEntry<>("New files", newFilesContent))
        .filter(entry -> !entry.getValue().isEmpty())
        .map(entry -> "%s:\n%s".formatted(entry.getKey(), entry.getValue()))
        .collect(joining("\n\n"));
  }

  private String getGitDiff(String projectPath, List<String> filePaths, boolean cached) {
    if (filePaths.isEmpty()) {
      return "";
    }

    var process = createGitDiffProcess(projectPath, filePaths, cached);
    return new BufferedReader(new InputStreamReader(process.getInputStream()))
        .lines()
        .collect(joining("\n"));
  }

  private String getNewFilesDiff(String projectPath, List<String> filePaths) {
    return filePaths.stream()
        .map(pathString -> {
          var filePath = Path.of(pathString);
          var relativePath = Path.of(projectPath).relativize(filePath);
          try {
            return "New file '" + relativePath + "' content:\n" + Files.readString(filePath);
          } catch (IOException ignored) {
            return null;
          }
        })
        .filter(Objects::nonNull)
        .collect(joining("\n"));
  }

  private Process createGitDiffProcess(String projectPath, List<String> filePaths, boolean cached) {
    var command = new ArrayList<String>();
    command.add("git");
    command.add("diff");
    if (cached) {
      command.add("--cached");
    }
    command.addAll(filePaths);

    var processBuilder = new ProcessBuilder(command);
    processBuilder.directory(new File(projectPath));
    try {
      return processBuilder.start();
    } catch (IOException ex) {
      throw new RuntimeException("Unable to start git diff process", ex);
    }
  }

  static class CommitWorkflowChanges {

    private final List<String> includedVersionedFilePaths;
    private final List<String> includedUnversionedFilePaths;

    CommitWorkflowChanges(CommitWorkflowUi commitWorkflowUi) {
      includedVersionedFilePaths = commitWorkflowUi.getIncludedChanges().stream()
          .map(it -> it.getVirtualFile() == null ? null : it.getVirtualFile().getPath())
          .filter(Objects::nonNull)
          .toList();
      includedUnversionedFilePaths = commitWorkflowUi.getIncludedUnversionedFiles().stream()
          .map(FilePath::getPath)
          .toList();
    }

    public List<String> getIncludedVersionedFilePaths() {
      return includedVersionedFilePaths;
    }

    public List<String> getIncludedUnversionedFilePaths() {
      return includedUnversionedFilePaths;
    }

    public boolean isFilesSelected() {
      return !includedVersionedFilePaths.isEmpty() || !includedUnversionedFilePaths.isEmpty();
    }
  }
}