src/main/java/de/uapcore/lightpit/modules/ProjectsModule.java

/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
 *
 * Copyright 2018 Mike Becker. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 *   1. Redistributions of source code must retain the above copyright
 *      notice, this list of conditions and the following disclaimer.
 *
 *   2. Redistributions in binary form must reproduce the above copyright
 *      notice, this list of conditions and the following disclaimer in the
 *      documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *
 */
package de.uapcore.lightpit.modules;


import de.uapcore.lightpit.*;
import de.uapcore.lightpit.dao.DaoProvider;
import de.uapcore.lightpit.entities.*;
import de.uapcore.lightpit.types.WebColor;
import de.uapcore.lightpit.viewmodel.*;
import de.uapcore.lightpit.viewmodel.util.IssueSorter;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.sql.Date;
import java.sql.SQLException;
import java.util.List;
import java.util.NoSuchElementException;
import java.util.Optional;
import java.util.stream.Collectors;
import java.util.stream.Stream;

@WebServlet(
        name = "ProjectsModule",
        urlPatterns = "/projects/*"
)
public final class ProjectsModule extends AbstractLightPITServlet {

    private static final Logger LOG = LoggerFactory.getLogger(ProjectsModule.class);

    @Override
    protected String getResourceBundleName() {
        return "localization.projects";
    }

    private static int parseIntOrZero(String str) {
        try {
            return Integer.parseInt(str);
        } catch (NumberFormatException ex) {
            return 0;
        }
    }

    private void populate(ProjectView viewModel, PathParameters pathParameters, DaoProvider dao) {
        final var projectDao = dao.getProjectDao();
        final var versionDao = dao.getVersionDao();
        final var componentDao = dao.getComponentDao();

        projectDao.list().stream().map(ProjectInfo::new).forEach(viewModel.getProjectList()::add);

        if (pathParameters == null)
            return;

        // Select Project
        final var project = projectDao.findByNode(pathParameters.get("project"));
        if (project == null)
            return;

        final var info = new ProjectInfo(project);
        info.setVersions(versionDao.list(project));
        info.setComponents(componentDao.list(project));
        info.setIssueSummary(projectDao.getIssueSummary(project));
        viewModel.setProjectInfo(info);

        // Select Version
        final var versionNode = pathParameters.get("version");
        if (versionNode != null) {
            if ("no-version".equals(versionNode)) {
                viewModel.setVersionFilter(ProjectView.NO_VERSION);
            } else if ("all-versions".equals(versionNode)) {
                viewModel.setVersionFilter(ProjectView.ALL_VERSIONS);
            } else {
                viewModel.setVersionFilter(versionDao.findByNode(project, versionNode));
            }
        }

        // Select Component
        final var componentNode = pathParameters.get("component");
        if (componentNode != null) {
            if ("no-component".equals(componentNode)) {
                viewModel.setComponentFilter(ProjectView.NO_COMPONENT);
            } else if ("all-components".equals(componentNode)) {
                viewModel.setComponentFilter(ProjectView.ALL_COMPONENTS);
            } else {
                viewModel.setComponentFilter(componentDao.findByNode(project, componentNode));
            }
        }
    }

    private static String sanitizeNode(String node, String defaultValue) {
        String result = node == null || node.isBlank() ? defaultValue : node;
        result = result.replace('/', '-');
        if (result.equals(".") || result.equals("..")) {
            return "_"+result;
        } else {
            return result;
        }
    }

    private void forwardView(HttpServletRequest req, HttpServletResponse resp, ProjectView viewModel, String name) throws ServletException, IOException {
        setViewModel(req, viewModel);
        setContentPage(req, name);
        setStylesheet(req, "projects");
        setNavigationMenu(req, "project-navmenu");
        renderSite(req, resp);
    }

    @RequestMapping(method = HttpMethod.GET)
    public void index(HttpServletRequest req, HttpServletResponse resp, DaoProvider dao) throws SQLException, ServletException, IOException {
        final var viewModel = new ProjectView();
        populate(viewModel, null, dao);

        final var projectDao = dao.getProjectDao();
        final var versionDao = dao.getVersionDao();

        for (var info : viewModel.getProjectList()) {
            info.setVersions(versionDao.list(info.getProject()));
            info.setIssueSummary(projectDao.getIssueSummary(info.getProject()));
        }

        forwardView(req, resp, viewModel, "projects");
    }

    private void configureProjectEditor(ProjectEditView viewModel, Project project, DaoProvider dao) throws SQLException {
        viewModel.setProject(project);
        viewModel.setUsers(dao.getUserDao().list());
    }

    @RequestMapping(requestPath = "$project/edit", method = HttpMethod.GET)
    public void edit(HttpServletRequest req, HttpServletResponse resp, PathParameters pathParams, DaoProvider dao) throws IOException, SQLException, ServletException {
        final var viewModel = new ProjectEditView();
        populate(viewModel, pathParams, dao);

        if (!viewModel.isProjectInfoPresent()) {
            resp.sendError(HttpServletResponse.SC_NOT_FOUND);
            return;
        }

        configureProjectEditor(viewModel, viewModel.getProjectInfo().getProject(), dao);
        forwardView(req, resp, viewModel, "project-form");
    }

    @RequestMapping(requestPath = "create", method = HttpMethod.GET)
    public void create(HttpServletRequest req, HttpServletResponse resp, DaoProvider dao) throws SQLException, ServletException, IOException {
        final var viewModel = new ProjectEditView();
        populate(viewModel, null, dao);
        configureProjectEditor(viewModel, new Project(-1), dao);
        forwardView(req, resp, viewModel, "project-form");
    }

    @RequestMapping(requestPath = "commit", method = HttpMethod.POST)
    public void commit(HttpServletRequest req, HttpServletResponse resp, DaoProvider dao) throws IOException, ServletException {

        try {
            final var project = new Project(getParameter(req, Integer.class, "pid").orElseThrow());
            project.setName(getParameter(req, String.class, "name").orElseThrow());

            final var node = getParameter(req, String.class, "node").orElse(null);
            project.setNode(sanitizeNode(node, project.getName()));

            getParameter(req, String.class, "description").ifPresent(project::setDescription);
            getParameter(req, String.class, "repoUrl").ifPresent(project::setRepoUrl);
            getParameter(req, Integer.class, "owner").map(
                    ownerId -> ownerId >= 0 ? new User(ownerId) : null
            ).ifPresent(project::setOwner);

            final var projectDao = dao.getProjectDao();
            if (project.getId() > 0) {
                // TODO: unused return value
                projectDao.update(project);
            } else {
                projectDao.save(project);
            }

            setRedirectLocation(req, "./projects/");
            setContentPage(req, Constants.JSP_COMMIT_SUCCESSFUL);
            LOG.debug("Successfully updated project {}", project.getName());

            renderSite(req, resp);
        } catch (NoSuchElementException | IllegalArgumentException ex) {
            resp.sendError(HttpServletResponse.SC_NOT_IMPLEMENTED);
            // TODO: implement - fix issue #21
        }
    }

    @RequestMapping(requestPath = "$project/$component/$version/issues/", method = HttpMethod.GET)
    public void issues(HttpServletRequest req, HttpServletResponse resp, PathParameters pathParams, DaoProvider dao) throws SQLException, IOException, ServletException {
        final var viewModel = new ProjectDetailsView();
        populate(viewModel, pathParams, dao);

        if (!viewModel.isEveryFilterValid()) {
            resp.sendError(HttpServletResponse.SC_NOT_FOUND);
            return;
        }

        final var project = viewModel.getProjectInfo().getProject();
        final var version = viewModel.getVersionFilter();
        final var component = viewModel.getComponentFilter();

        final var issueDao = dao.getIssueDao();

        final List<Issue> issues;
        if (version.equals(ProjectView.NO_VERSION)) {
            if (component.equals(ProjectView.ALL_COMPONENTS)) {
                issues = issueDao.list(project, (Version) null);
            } else if (component.equals(ProjectView.NO_COMPONENT)) {
                issues = issueDao.list(project, null, null);
            } else {
                issues = issueDao.list(project, component, null);
            }
        } else if (version.equals(ProjectView.ALL_VERSIONS)) {
            if (component.equals(ProjectView.ALL_COMPONENTS)) {
                issues = issueDao.list(project);
            } else if (component.equals(ProjectView.NO_COMPONENT)) {
                issues = issueDao.list(project, (Component)null);
            } else {
                issues = issueDao.list(project, component);
            }
        } else {
            if (component.equals(ProjectView.ALL_COMPONENTS)) {
                issues = issueDao.list(project, version);
            } else if (component.equals(ProjectView.NO_COMPONENT)) {
                issues = issueDao.list(project, null, version);
            } else {
                issues = issueDao.list(project, component, version);
            }
        }

        for (var issue : issues) issueDao.joinVersionInformation(issue);
        issues.sort(new IssueSorter(
                new IssueSorter.Criteria(IssueSorter.Field.DONE, true),
                new IssueSorter.Criteria(IssueSorter.Field.ETA, true),
                new IssueSorter.Criteria(IssueSorter.Field.UPDATED, false)
        ));


        viewModel.getProjectDetails().updateDetails(issues);
        if (version.getId() > 0)
            viewModel.getProjectDetails().updateVersionInfo(version);

        forwardView(req, resp, viewModel, "project-details");
    }

    @RequestMapping(requestPath = "$project/versions/", method = HttpMethod.GET)
    public void versions(HttpServletRequest req, HttpServletResponse resp, PathParameters pathParameters, DaoProvider dao) throws IOException, SQLException, ServletException {
        final var viewModel = new VersionsView();
        populate(viewModel, pathParameters, dao);

        final var projectInfo = viewModel.getProjectInfo();
        if (projectInfo == null) {
            resp.sendError(HttpServletResponse.SC_NOT_FOUND);
            return;
        }

        final var issueDao = dao.getIssueDao();
        final var issues = issueDao.list(projectInfo.getProject());
        for (var issue : issues) issueDao.joinVersionInformation(issue);
        viewModel.update(projectInfo.getVersions(), issues);

        forwardView(req, resp, viewModel, "versions");
    }

    @RequestMapping(requestPath = "$project/versions/$version/edit", method = HttpMethod.GET)
    public void editVersion(HttpServletRequest req, HttpServletResponse resp, PathParameters pathParameters, DaoProvider dao) throws IOException, SQLException, ServletException {
        final var viewModel = new VersionEditView();
        populate(viewModel, pathParameters, dao);

        if (viewModel.getProjectInfo() == null || viewModel.getVersionFilter() == null) {
            resp.sendError(HttpServletResponse.SC_NOT_FOUND);
            return;
        }

        viewModel.setVersion(viewModel.getVersionFilter());

        forwardView(req, resp, viewModel, "version-form");
    }

    @RequestMapping(requestPath = "$project/create-version", method = HttpMethod.GET)
    public void createVersion(HttpServletRequest req, HttpServletResponse resp, PathParameters pathParameters, DaoProvider dao) throws IOException, SQLException, ServletException {
        final var viewModel = new VersionEditView();
        populate(viewModel, pathParameters, dao);

        if (viewModel.getProjectInfo() == null) {
            resp.sendError(HttpServletResponse.SC_NOT_FOUND);
            return;
        }

        viewModel.setVersion(new Version(-1));

        forwardView(req, resp, viewModel, "version-form");
    }

    @RequestMapping(requestPath = "commit-version", method = HttpMethod.POST)
    public void commitVersion(HttpServletRequest req, HttpServletResponse resp, DaoProvider dao) throws IOException, ServletException {

        try {
            final var project = dao.getProjectDao().find(getParameter(req, Integer.class, "pid").orElseThrow());
            if (project == null) {
                // TODO: improve error handling, because not found is not correct for this POST request
                resp.sendError(HttpServletResponse.SC_NOT_FOUND);
                return;
            }
            final var version = new Version(getParameter(req, Integer.class, "id").orElseThrow());
            version.setName(getParameter(req, String.class, "name").orElseThrow());

            final var node = getParameter(req, String.class, "node").orElse(null);
            version.setNode(sanitizeNode(node, version.getName()));

            getParameter(req, Integer.class, "ordinal").ifPresent(version::setOrdinal);
            version.setStatus(VersionStatus.valueOf(getParameter(req, String.class, "status").orElseThrow()));

            final var versionDao = dao.getVersionDao();
            if (version.getId() > 0) {
                // TODO: use return value
                versionDao.update(version);
            } else {
                versionDao.save(version, project);
            }

            setRedirectLocation(req, "./projects/" + project.getNode() + "/versions/");
            setContentPage(req, Constants.JSP_COMMIT_SUCCESSFUL);

            renderSite(req, resp);
        } catch (NoSuchElementException | IllegalArgumentException ex) {
            resp.sendError(HttpServletResponse.SC_NOT_IMPLEMENTED);
            // TODO: implement - fix issue #21
        }
    }

    @RequestMapping(requestPath = "$project/components/", method = HttpMethod.GET)
    public void components(HttpServletRequest req, HttpServletResponse resp, PathParameters pathParameters, DaoProvider dao) throws IOException, SQLException, ServletException {
        final var viewModel = new ComponentsView();
        populate(viewModel, pathParameters, dao);

        final var projectInfo = viewModel.getProjectInfo();
        if (projectInfo == null) {
            resp.sendError(HttpServletResponse.SC_NOT_FOUND);
            return;
        }

        final var issueDao = dao.getIssueDao();
        final var issues = issueDao.list(projectInfo.getProject());
        viewModel.update(projectInfo.getComponents(), issues);

        forwardView(req, resp, viewModel, "components");
    }

    @RequestMapping(requestPath = "$project/components/$component/edit", method = HttpMethod.GET)
    public void editComponent(HttpServletRequest req, HttpServletResponse resp, PathParameters pathParameters, DaoProvider dao) throws IOException, SQLException, ServletException {
        final var viewModel = new ComponentEditView();
        populate(viewModel, pathParameters, dao);

        if (viewModel.getProjectInfo() == null || viewModel.getComponentFilter() == null) {
            resp.sendError(HttpServletResponse.SC_NOT_FOUND);
            return;
        }

        viewModel.setComponent(viewModel.getComponentFilter());
        viewModel.setUsers(dao.getUserDao().list());

        forwardView(req, resp, viewModel, "component-form");
    }

    @RequestMapping(requestPath = "$project/create-component", method = HttpMethod.GET)
    public void createComponent(HttpServletRequest req, HttpServletResponse resp, PathParameters pathParameters, DaoProvider dao) throws IOException, SQLException, ServletException {
        final var viewModel = new ComponentEditView();
        populate(viewModel, pathParameters, dao);

        if (viewModel.getProjectInfo() == null) {
            resp.sendError(HttpServletResponse.SC_NOT_FOUND);
            return;
        }

        viewModel.setComponent(new Component(-1));
        viewModel.setUsers(dao.getUserDao().list());

        forwardView(req, resp, viewModel, "component-form");
    }

    @RequestMapping(requestPath = "commit-component", method = HttpMethod.POST)
    public void commitComponent(HttpServletRequest req, HttpServletResponse resp, DaoProvider dao) throws IOException, ServletException {

        try {
            final var project = dao.getProjectDao().find(getParameter(req, Integer.class, "pid").orElseThrow());
            if (project == null) {
                // TODO: improve error handling, because not found is not correct for this POST request
                resp.sendError(HttpServletResponse.SC_NOT_FOUND);
                return;
            }
            final var component = new Component(getParameter(req, Integer.class, "id").orElseThrow());
            component.setName(getParameter(req, String.class, "name").orElseThrow());

            final var node = getParameter(req, String.class, "node").orElse(null);
            component.setNode(sanitizeNode(node, component.getName()));

            component.setColor(getParameter(req, WebColor.class, "color").orElseThrow());
            getParameter(req, Integer.class, "ordinal").ifPresent(component::setOrdinal);
            getParameter(req, Integer.class, "lead").map(
                    userid -> userid >= 0 ? new User(userid) : null
            ).ifPresent(component::setLead);
            getParameter(req, String.class, "description").ifPresent(component::setDescription);

            final var componentDao = dao.getComponentDao();
            if (component.getId() > 0) {
                // TODO: use return value
                componentDao.update(component);
            } else {
                componentDao.save(component, project);
            }

            setRedirectLocation(req, "./projects/" + project.getNode() + "/components/");
            setContentPage(req, Constants.JSP_COMMIT_SUCCESSFUL);

            renderSite(req, resp);
        } catch (NoSuchElementException | IllegalArgumentException ex) {
            resp.sendError(HttpServletResponse.SC_NOT_IMPLEMENTED);
            // TODO: implement - fix issue #21
        }
    }

    private void configureIssueEditor(IssueEditView viewModel, Issue issue, DaoProvider dao) throws SQLException {
        final var project = viewModel.getProjectInfo().getProject();
        issue.setProject(project); // automatically set current project for new issues
        viewModel.setIssue(issue);
        viewModel.configureVersionSelectors(viewModel.getProjectInfo().getVersions());
        viewModel.setUsers(dao.getUserDao().list());
        viewModel.setComponents(dao.getComponentDao().list(project));
    }

    @RequestMapping(requestPath = "$project/issues/$issue/view", method = HttpMethod.GET)
    public void viewIssue(HttpServletRequest req, HttpServletResponse resp, PathParameters pathParameters, DaoProvider dao) throws IOException, SQLException, ServletException {
        final var viewModel = new IssueDetailView();
        populate(viewModel, pathParameters, dao);

        final var projectInfo = viewModel.getProjectInfo();
        if (projectInfo == null) {
            resp.sendError(HttpServletResponse.SC_NOT_FOUND);
            return;
        }

        final var issueDao = dao.getIssueDao();
        final var issue = issueDao.find(parseIntOrZero(pathParameters.get("issue")));
        if (issue == null) {
            resp.sendError(HttpServletResponse.SC_NOT_FOUND);
            return;
        }

        issueDao.joinVersionInformation(issue);
        viewModel.setIssue(issue);
        viewModel.setComments(issueDao.listComments(issue));

        viewModel.processMarkdown();

        forwardView(req, resp, viewModel, "issue-view");
    }

    // TODO: why should the issue editor be child of $project?
    @RequestMapping(requestPath = "$project/issues/$issue/edit", method = HttpMethod.GET)
    public void editIssue(HttpServletRequest req, HttpServletResponse resp, PathParameters pathParameters, DaoProvider dao) throws IOException, SQLException, ServletException {
        final var viewModel = new IssueEditView();
        populate(viewModel, pathParameters, dao);

        final var projectInfo = viewModel.getProjectInfo();
        if (projectInfo == null) {
            resp.sendError(HttpServletResponse.SC_NOT_FOUND);
            return;
        }

        final var issueDao = dao.getIssueDao();
        final var issue = issueDao.find(parseIntOrZero(pathParameters.get("issue")));
        if (issue == null) {
            resp.sendError(HttpServletResponse.SC_NOT_FOUND);
            return;
        }

        issueDao.joinVersionInformation(issue);
        configureIssueEditor(viewModel, issue, dao);

        forwardView(req, resp, viewModel, "issue-form");
    }

    @RequestMapping(requestPath = "$project/create-issue", method = HttpMethod.GET)
    public void createIssue(HttpServletRequest req, HttpServletResponse resp, PathParameters pathParameters, DaoProvider dao) throws IOException, SQLException, ServletException {
        final var viewModel = new IssueEditView();
        populate(viewModel, pathParameters, dao);

        final var projectInfo = viewModel.getProjectInfo();
        if (projectInfo == null) {
            resp.sendError(HttpServletResponse.SC_NOT_FOUND);
            return;
        }

        final var issue = new Issue(-1);
        issue.setProject(projectInfo.getProject());
        configureIssueEditor(viewModel, issue, dao);

        forwardView(req, resp, viewModel, "issue-form");
    }

    @RequestMapping(requestPath = "commit-issue", method = HttpMethod.POST)
    public void commitIssue(HttpServletRequest req, HttpServletResponse resp, DaoProvider dao) throws IOException, ServletException {
        try {
            final var issue = new Issue(getParameter(req, Integer.class, "id").orElseThrow());
            final var componentId = getParameter(req, Integer.class, "component");
            final Component component;
            if (componentId.isPresent()) {
                component = dao.getComponentDao().find(componentId.get());
            } else {
                component = null;
            }
            final var project = dao.getProjectDao().find(getParameter(req, Integer.class, "pid").orElseThrow());
            if (project == null) {
                // TODO: improve error handling, because not found is not correct for this POST request
                resp.sendError(HttpServletResponse.SC_NOT_FOUND);
                return;
            }
            issue.setProject(project);
            getParameter(req, String.class, "category").map(IssueCategory::valueOf).ifPresent(issue::setCategory);
            getParameter(req, String.class, "status").map(IssueStatus::valueOf).ifPresent(issue::setStatus);
            issue.setSubject(getParameter(req, String.class, "subject").orElseThrow());
            issue.setComponent(component);
            getParameter(req, Integer.class, "assignee").map(userid -> {
                if (userid >= 0) {
                    return new User(userid);
                } else if (userid == -2) {
                    return Optional.ofNullable(component).map(Component::getLead).orElse(null);
                } else {
                    return null;
                }
            }
            ).ifPresent(issue::setAssignee);
            getParameter(req, String.class, "description").ifPresent(issue::setDescription);
            getParameter(req, Date.class, "eta").ifPresent(issue::setEta);

            getParameter(req, Integer[].class, "affected")
                    .map(Stream::of)
                    .map(stream ->
                            stream.map(Version::new).collect(Collectors.toList())
                    ).ifPresent(issue::setAffectedVersions);
            getParameter(req, Integer[].class, "resolved")
                    .map(Stream::of)
                    .map(stream ->
                            stream.map(Version::new).collect(Collectors.toList())
                    ).ifPresent(issue::setResolvedVersions);

            final var issueDao = dao.getIssueDao();
            if (issue.getId() > 0) {
                // TODO: use return value
                issueDao.update(issue);
            } else {
                issueDao.save(issue, project);
            }

            // TODO: fix redirect location
            setRedirectLocation(req, "./projects/" + issue.getProject().getNode()+"/issues/"+issue.getId()+"/view");
            setContentPage(req, Constants.JSP_COMMIT_SUCCESSFUL);

            renderSite(req, resp);
        } catch (NoSuchElementException | IllegalArgumentException ex) {
            resp.sendError(HttpServletResponse.SC_NOT_IMPLEMENTED);
            // TODO: implement - fix issue #21
        }
    }

    @RequestMapping(requestPath = "commit-issue-comment", method = HttpMethod.POST)
    public void commentIssue(HttpServletRequest req, HttpServletResponse resp, DaoProvider dao) throws IOException, ServletException {
        final var issueIdParam = getParameter(req, Integer.class, "issueid");
        if (issueIdParam.isEmpty()) {
            resp.sendError(HttpServletResponse.SC_FORBIDDEN, "Detected manipulated form.");
            return;
        }
        final var issue = dao.getIssueDao().find(issueIdParam.get());
        if (issue == null) {
            resp.sendError(HttpServletResponse.SC_NOT_FOUND);
            return;
        }
        try {
            final var issueComment = new IssueComment(getParameter(req, Integer.class, "commentid").orElse(-1));
            issueComment.setComment(getParameter(req, String.class, "comment").orElse(""));

            if (issueComment.getComment().isBlank()) {
                throw new IllegalArgumentException("comment.null");
            }

            LOG.debug("User {} is commenting on issue #{}", req.getRemoteUser(), issue.getId());
            if (req.getRemoteUser() != null) {
                Optional.ofNullable(dao.getUserDao().findByUsername(req.getRemoteUser())).ifPresent(issueComment::setAuthor);
            }

            dao.getIssueDao().saveComment(issue, issueComment);

            // TODO: fix redirect location
            setRedirectLocation(req, "./projects/" + issue.getProject().getNode()+"/issues/"+issue.getId()+"/view");
            setContentPage(req, Constants.JSP_COMMIT_SUCCESSFUL);

            renderSite(req, resp);
        } catch (NoSuchElementException | IllegalArgumentException ex) {
            resp.sendError(HttpServletResponse.SC_NOT_IMPLEMENTED);
            // TODO: implement - fix issue #21
        }
    }
}