Logger.java

package org.elixir_lang.errorreport;

import com.google.common.base.Joiner;
import com.intellij.diagnostic.AttachmentFactory;
import com.intellij.diagnostic.LogMessageEx;
import com.intellij.openapi.diagnostic.Attachment;
import com.intellij.openapi.editor.Document;
import com.intellij.openapi.util.TextRange;
import com.intellij.openapi.vfs.VirtualFile;
import com.intellij.psi.FileViewProvider;
import com.intellij.psi.PsiElement;
import com.intellij.psi.PsiFile;
import org.jetbrains.annotations.NotNull;

import java.util.Collection;
import java.util.Collections;

public class Logger {
    /*
     * Public Static Methods
     */

    /**
     * Logs error to the {@code klass}'s {@link com.intellij.openapi.diagnostic.Logger} instance with the given
     * {@code userMessage} and the text of {@code element} as the details and containing file of {@code element} as an
     * attachment
     *
     * @param klass       Class whose logger to use
     * @param userMessage User message for
     *                    {@link com.intellij.diagnostic.LogMessageEx#createEvent(String, String, Attachment...)}
     * @param element     element responsible for the error
     */
    public static void error(@NotNull Class klass, @NotNull String userMessage, PsiElement element) {
        error(com.intellij.openapi.diagnostic.Logger.getInstance(klass), userMessage, element);
    }

    /**
     * Logs error {@link com.intellij.openapi.diagnostic.Logger} instance with the given {@code userMessage} and the
     * text of {@code element} as the details and containing file of {@code element} as an * attachment
     *
     * @param logger      logger to which to log an error.
     * @param userMessage User message for
     *                    {@link com.intellij.diagnostic.LogMessageEx#createEvent(String, String, Attachment...)}
     * @param element     element responsible for the error
     */
    public static void error(@NotNull com.intellij.openapi.diagnostic.Logger logger,
                             @NotNull String userMessage,
                             @NotNull PsiElement element) {
        PsiFile containingFile = element.getContainingFile();
        String fullUserMessage = fullUserMessage(userMessage, containingFile, element);
        String details = Joiner.on("\n").join(new Throwable().getStackTrace());

        Collection<Attachment> attachmentCollection;

        VirtualFile virtualFile = containingFile.getVirtualFile();

        if (virtualFile != null) {
            attachmentCollection = Collections.singletonList(
                    AttachmentFactory.createAttachment(virtualFile)
            );
        } else {
            attachmentCollection = Collections.emptyList();
        }

        logger.error(
                LogMessageEx.createEvent(
                        fullUserMessage,
                        details,
                        fullUserMessage,
                        null,
                        attachmentCollection
                )
        );
    }

    /*
     * Private Static Methods
     */

    @NotNull
    private static String className(@NotNull PsiElement element) {
        return "\n" +
                "### Element Class Name\n" +
                '\n' +
                "```\n" +
                element.getClass().getName() +
                '\n' +
                "```\n";
    }

    @NotNull
    private static String excerpt(@NotNull PsiFile containingFile, @NotNull PsiElement element) {
        StringBuilder excerptBuilder = new StringBuilder();
        excerptBuilder.append('\n');
        excerptBuilder.append("### Excerpt\n");
        excerptBuilder.append('\n');

        excerptBuilder.append("```\n");
        excerptBuilder.append(element.getText());
        excerptBuilder.append('\n');
        excerptBuilder.append("```\n");

        FileViewProvider fileViewProvider = containingFile.getViewProvider();
        Document document = fileViewProvider.getDocument();

        if (document != null) {
            TextRange textRange = element.getTextRange();
            int startingLine = document.getLineNumber(textRange.getStartOffset());
            int endingLine = document.getLineNumber(textRange.getEndOffset());

            excerptBuilder.append(" Line(s) ");
            excerptBuilder.append(startingLine);
            excerptBuilder.append('-');
            excerptBuilder.append(endingLine);

            VirtualFile virtualFile = containingFile.getVirtualFile();

            if (virtualFile != null) {
                excerptBuilder.append(" in ");
                excerptBuilder.append(virtualFile.getPath());
            }

            excerptBuilder.append("\n");
        }

        return excerptBuilder.toString();
    }

    private static String fullUserMessage(@NotNull String userMessage,
                                          @NotNull PsiFile containingFile,
                                          @NotNull PsiElement element) {
        return userMessage + "\n" +
                excerpt(containingFile, element) + "\n" +
                className(element);
    }
}