Gitea-Helpdesk/src/main/java/io/gitlab/jfronny/gitea/helpdesk/web/WebInterface.java

package io.gitlab.jfronny.gitea.helpdesk.web;

import io.gitlab.jfronny.commons.StringFormatter;
import io.gitlab.jfronny.gitea.helpdesk.Config;
import io.gitlab.jfronny.gitea.helpdesk.Main;
import io.gitlab.jfronny.gitea.helpdesk.db.DBInterface;
import io.gitlab.jfronny.gitea.helpdesk.gitea.GiteaInterface;
import net.freeutils.httpserver.HTTPServer;

import java.io.IOException;
import java.io.UncheckedIOException;
import java.net.URISyntaxException;
import java.nio.charset.StandardCharsets;
import java.util.Map;

public class WebInterface implements AutoCloseable {
    public static final String THEME = Main.getResource("/web/theme.css");
    private static final String TEMPLATE = Main.getResource("/web/template.html");
    private static final String ISSUE_MISSING_REPO = Main.getResource("/web/issue/missing_repo.html");
    private static final String ISSUE_SUCCESS = Main.getResource("/web/issue/success.html");
    private static final String REPLY_MISSING_REPO = Main.getResource("/web/reply/missing_repo.html");
    private static final String REPLY_SUCCESS = Main.getResource("/web/reply/success.html");
    private static final String UNSUBSCRIBE_MISSING_ID = Main.getResource("/web/unsubscribe/missing_id.html");
    private static final String UNSUBSCRIBE_FAILURE = Main.getResource("/web/unsubscribe/failure.html");
    private static final String UNSUBSCRIBE_SUCCESS = Main.getResource("/web/unsubscribe/success.html");
    private static final String CLOSE_MISSING_ID = Main.getResource("/web/close/missing_id.html");
    private static final String CLOSE_FAILURE = Main.getResource("/web/close/failure.html");
    private static final String CLOSE_NOT_CREATOR = Main.getResource("/web/close/not_creator.html");
    private static final String CLOSE_SUCCESS = Main.getResource("/web/close/success.html");

    private String template(String body) {
        return TEMPLATE.replace("<%template-content%>", body);
    }

    private final HTTPServer server;
    private final Config.Web web;

    public WebInterface(Config.Web web, String address, DBInterface db, GiteaInterface gitea) throws IOException {
        server = new HTTPServer(web.port);
        this.web = web;
        HTTPServer.VirtualHost host = server.getVirtualHost(null);
        host.addContext("/unsubscribe", (req, resp) -> {
            String id = req.getParams().get("id");
            if (id == null) {
                resp.send(404, template(UNSUBSCRIBE_MISSING_ID));
            } else {
                try {
                    db.removeSubscription(id);
                    resp.send(202, template(UNSUBSCRIBE_SUCCESS));
                } catch (Throwable e) {
                    resp.send(500, template(UNSUBSCRIBE_FAILURE.formatted(escapeHTML(StringFormatter.toString(e)))));
                }
            }
            return 0;
        });
        host.addContext("/close", ((req, resp) -> {
            String id = req.getParams().get("id");
            if (id == null) {
                resp.send(404, template(CLOSE_MISSING_ID));
            } else {
                try {
                    db.getSubscription(id).ifPresentOrElse(sub -> {
                        try {
                            if (sub.creator()) {
                                gitea.closeIssue(sub.repoOwner(), sub.repo(), sub.issue());
                                resp.send(202, template(CLOSE_SUCCESS));
                            } else {
                                resp.send(403, template(CLOSE_NOT_CREATOR));
                            }
                        } catch (IOException e) {
                            throw new UncheckedIOException(e);
                        } catch (URISyntaxException e) {
                            throw new RuntimeException(e);
                        }
                    }, () -> {
                        try {
                            resp.send(404, template(CLOSE_MISSING_ID));
                        } catch (IOException e) {
                            throw new UncheckedIOException(e);
                        }
                    });
                } catch (Throwable e) {
                    resp.send(500, template(CLOSE_FAILURE.formatted(escapeHTML(StringFormatter.toString(e)))));
                }
            }
            return 0;
        }));
        String[] addr = address.split("@");
        host.addContext("/issue", (req, resp) -> {
            Map<String, String> params = req.getParams();
            String owner = params.get("owner");
            String repo = params.get("repo");
            if (owner == null || repo == null || !Main.PATH_SEGMENT_PATTERN.matcher(owner).matches() || !Main.PATH_SEGMENT_PATTERN.matcher(repo).matches()) {
                resp.send(404, template(ISSUE_MISSING_REPO));
            } else {
                String mail = "mailto:" + addr[0] + "+create+" + owner + '+' + repo + '@' + addr[1];
                resp.send(200, template(ISSUE_SUCCESS.formatted(escapeHTML(mail))));
            }
            return 0;
        });
        host.addContext("/comment", (req, resp) -> {
            Map<String, String> params = req.getParams();
            String owner = params.get("owner");
            String repo = params.get("repo");
            String issueId = params.get("id");
            if (owner == null || repo == null || !Main.PATH_SEGMENT_PATTERN.matcher(owner).matches() || !Main.PATH_SEGMENT_PATTERN.matcher(repo).matches() || !Main.NUMBER_PATTERN.matcher(issueId).matches()) {
                resp.send(404, template(REPLY_MISSING_REPO));
            } else {
                String mail = "mailto:" + addr[0] + "+comment+" + owner + '+' + repo + '+' + issueId + '@' + addr[1];
                resp.send(200, template(REPLY_SUCCESS.formatted(escapeHTML(mail))));
            }
            return 0;
        });
        host.addContext("/theme.css", (req, resp) -> {
            byte[] content = THEME.getBytes(StandardCharsets.UTF_8);
            resp.sendHeaders(200, content.length, -1, "W/\"" + Integer.toHexString(THEME.hashCode()) + "\"", "text/css; charset=utf-8", null);
            resp.getBody().write(content);
            return 0;
        });
        server.start();
    }

    @Override
    public void close() {
        server.stop();
    }

    public static String escapeHTML(String s) {
        StringBuilder out = new StringBuilder();
        for (int i = 0; i < s.length(); i++) {
            char c = s.charAt(i);
            if (c > 127 || c == '"' || c == '\'' || c == '<' || c == '>' || c == '&') {
                out.append("&#");
                out.append((int) c);
                out.append(';');
            } else if (c == '\n') {
                out.append("<br>\n");
            } else {
                out.append(c);
            }
        }
        return out.toString();
    }

    public String getAddress() {
        return web.publicAddress;
    }
}