import java.io.IOException;
import java.io.PrintWriter;
import java.text.SimpleDateFormat;
import java.util.List;
 
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
 
import com.atlassian.jira.bc.issue.search.SearchService;
import com.atlassian.jira.component.ComponentAccessor;
import com.atlassian.jira.issue.Issue;
import com.atlassian.jira.issue.attachment.Attachment;
import com.atlassian.jira.issue.comments.Comment;
import com.atlassian.jira.issue.search.SearchException;
import com.atlassian.jira.jql.parser.JqlParseException;
import com.atlassian.jira.jql.parser.JqlQueryParser;
import com.atlassian.jira.user.ApplicationUser;
import com.atlassian.jira.web.bean.PagerFilter;
import com.atlassian.query.Query;
 
public class CommentDownloadServlet extends HttpServlet {
 
    private static final long serialVersionUID = 1L;
    private String email;
    private String jql;
    private String prefix;
 
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
 
        jql = req.getParameter("jql");
        email = req.getParameter("email");
        prefix = req.getParameter("prefix");
         
        List<Issue> issues = null;
        Query query = null;
 
        JqlQueryParser jqlQueryParser = ComponentAccessor.getComponent(JqlQueryParser.class);
 
         
        try {
            query = jqlQueryParser.parseQuery(jql);
 
            SearchService searchService = ComponentAccessor.getComponent(SearchService.class);
            ApplicationUser user = ComponentAccessor.getJiraAuthenticationContext().getLoggedInUser();
 
            issues = searchService.search(user, query, PagerFilter.getUnlimitedFilter()).getResults();
 
        } catch (JqlParseException e) {
            e.printStackTrace();
        } catch (SearchException e) {
            e.printStackTrace();
        }
 
        resp.setContentType("text/csv; charset=UTF-8");
        resp.addHeader("Content-Type", "text/csv; charset=UTF-8");
        resp.setHeader("Content-Disposition", "attachment; filename=comments.csv");
 
        String baseUrl = ComponentAccessor.getApplicationProperties().getString("jira.baseurl");
 
        PrintWriter writer = resp.getWriter();
        int maxCommentCount = 0;
        int maxAttachmentCount = 0;
        if (issues != null) {
            for (Issue issue : issues) {
                maxCommentCount = Math.max(maxCommentCount, ComponentAccessor.getCommentManager().getComments(issue).size());
            }
            for (Issue issue : issues) {
                maxAttachmentCount = Math.max(maxAttachmentCount, ComponentAccessor.getAttachmentManager().getAttachments(issue).size());
            }
            writer.append("Issue Key,");
            for (int i = 0; i < maxCommentCount; i++) {
                writer.append("Comment");
                if (i != maxCommentCount - 1) {
                    writer.append(",");
                }
            }
            writer.append(",");
            for (int i = 0; i < maxAttachmentCount; i++) {
                writer.append("Attachment");
                if (i != maxAttachmentCount - 1) {
                    writer.append(",");
                }
            }
            writer.append("\n");
            for (Issue issue : issues) {
                List<Comment> comments = ComponentAccessor.getCommentManager().getComments(issue);
                writer.append(issue.getKey() + ",");
                for (int i = 0; i < maxCommentCount; i++) {
                    if (i < comments.size()) {
                        Comment comment = comments.get(i);
                        SimpleDateFormat sdf = new SimpleDateFormat("MM/dd/yyyy h:mm a");
                        String date = sdf.format(comment.getCreated());
                         
                        String commentFixed = comment.getBody().replace("\"", "\"\"");
                        if(comment.getAuthorApplicationUser().getEmailAddress() == null || comment.getAuthorApplicationUser().getEmailAddress().equalsIgnoreCase("")) {
                            email = req.getParameter("email").toString();
                        } else {
                            email = comment.getAuthorApplicationUser().getEmailAddress();
                        }
                         
                        writer.append("\"" + date + "; " + comment.getAuthorApplicationUser().getEmailAddress() + ";" + commentFixed + "\"");
                    }
                    if (i != maxCommentCount - 1) {
                        writer.append(",");
                    }
                }
                writer.append(",");
                List<Attachment> attachments = ComponentAccessor.getAttachmentManager().getAttachments(issue);
                for (int i = 0; i < maxAttachmentCount; i++) {
                    if (i < attachments.size()) {
                        Attachment attachment = attachments.get(i);
                         
                        String base = prefix == null ? baseUrl+"/secure/attachment/" : prefix.trim()+"/download/";
                         
                        writer.append("\""+ base + attachment.getId() + "/" + attachment.getFilename() + "\"");
                    }
                    if (i != maxAttachmentCount - 1) {
                        writer.append(",");
                    }
                }
                writer.append("\n");
            }
        }
 
        writer.flush();
        writer.close();
    }
}