Ide script for showing git diff dialog between any two commits

ide_show_git_diff_ide_scripting.kt

import com.intellij.vcsUtil.VcsUtil
import git4idea.GitUtil
import git4idea.GitContentRevision
import git4idea.GitRevisionNumber
import com.intellij.openapi.vcs.history.VcsDiffUtil
import git4idea.changes.GitChangeUtils
import git4idea.history.GitHistoryUtils
import com.intellij.openapi.actionSystem.CommonDataKeys
import com.intellij.ide.DataManager
import com.intellij.dvcs.DvcsUtil
import com.intellij.openapi.vcs.VcsException
import java.util.Collections
import com.intellij.openapi.vfs.LocalFileSystem
import java.io.File
import com.intellij.openapi.project.ProjectManager

val branchToCompare = "HEAD~20"
val head = "HEAD"

val dataContext = DataManager.getInstance().dataContextFromFocusAsync.blockingGet(1000)!!
//    val project = CommonDataKeys.PROJECT.getData(dataContext)!!
val project = ProjectManager.getInstance().getOpenProjects()[0]
//    val selectedFile = LocalFileSystem.getInstance().findFileByIoFile(File("/Users/iisakov/Work/intellij-idea-badoo-components/"))
val selectedFile = project.getBaseDir()

//    val selectedFile = DvcsUtil.getSelectedFile(project)

var filePath = VcsUtil.getFilePath(selectedFile)
if (selectedFile != null) {

    var gitRepository = GitUtil.getRepositoryManager(project).getRepositoryForFile(selectedFile);

    if (gitRepository == null) {
        throw VcsException("Couldn't find Git Repository for " + selectedFile.getName())
    }
    var gitRepositoryRoot = gitRepository.getRoot();
    var compareRevisionNumber = GitRevisionNumber(branchToCompare);
    var changes = GitChangeUtils.getDiffWithWorkingDir(project, gitRepositoryRoot, branchToCompare, Collections.singletonList(filePath), false);

//        if (changes.isEmpty() && GitHistoryUtils.getCurrentRevision(project, filePath, branchToCompare) == null) {
//            throw VcsException("fileDoesntExistInBranchError")
//        }
//        if (changes.isEmpty() && !filePath.isDirectory()) {
//        changes = createChangesWithCurrentContentForFile(filePath, GitContentRevision.createRevision(filePath, compareRevisionNumber, project))
//        }

    if (changes != null) {
        VcsDiffUtil.showDiffFor(project, changes, VcsDiffUtil.getRevisionTitle(branchToCompare, false), VcsDiffUtil.getRevisionTitle(head, true), VcsUtil.getFilePath(selectedFile));
    }
}