package io.gitlab.jfronny.gitea.helpdesk;

import io.gitlab.jfronny.commons.StringFormatter;
import io.gitlab.jfronny.commons.throwable.ThrowingBiConsumer;
import io.gitlab.jfronny.gitea.helpdesk.db.DBInterface;
import io.gitlab.jfronny.gitea.helpdesk.db.Subscription;
import io.gitlab.jfronny.gitea.helpdesk.gitea.*;
import io.gitlab.jfronny.gitea.helpdesk.mail.MailInterface;
import io.gitlab.jfronny.gitea.helpdesk.mail.WrappedMessage;
import io.gitlab.jfronny.gitea.helpdesk.web.WebInterface;
import jakarta.mail.MessagingException;

import java.io.FileNotFoundException;
import java.io.IOException;
import java.sql.SQLException;

public record UpdateTask(DBInterface db, MailInterface mail, GiteaInterface gitea, WebInterface web) implements Runnable {
    private static final String TEMPLATE = Main.getResource("mail/template.html").formatted(WebInterface.THEME, "%s");
    private static final String MAIL_ERROR = mail("error.html");
    private static final String MAIL_UNEXPECTED = mail("unexpected.html");
    private static final String MAIL_CREATE = mail("create.html");
    private static final String MAIL_COMMENT = mail("comment.html");
    private static final String MAIL_COMMENT_CLOSED = mail("comment_closed.html");
    private static final String MAIL_ISSUE_DELETED = mail("issue_deleted.html");
    private static final String MAIL_ISSUE_CLOSED = mail("issue_closed.html");

    private static String mail(String path) {
        return TEMPLATE.formatted(Main.getResource("mail/" + path));
    }

    @Override
    public void run() {
        try {
            updateSubscriptions();
            processEmails();
        } catch (Exception e) {
            Main.LOG.error("Could not run update task", e);
        }
    }

    private void updateSubscriptions() throws Exception {
        String[] addressParts = mail.getAddress().split("@");
        db.forEachSubscription(subscription -> {
            ThrowingBiConsumer<String, String, Exception> reply = (content, subject) -> {
                String[] previousMessages = subscription.referenceChain().split(" ");
                String previousMessageId = previousMessages[previousMessages.length - 1];
                //TODO test
                mail.reply(addressParts[0] + "+reply+" + subscription.id(), subscription.email(), content, subject, previousMessageId, subscription.referenceChain(), null);
            };
            GiteaIssue issue;
            try {
                issue = gitea.getIssue(subscription.repoOwner(), subscription.repo(), subscription.issue());
            } catch (FileNotFoundException fe) {
                reply.accept(MAIL_ISSUE_DELETED, "Issue deleted");
                db.removeSubscription(subscription.id());
                return;
            }
            if (issue.state.equals("closed")) { //TODO test
                reply.accept(MAIL_ISSUE_CLOSED, "Issue closed");
                db.removeSubscription(subscription.id());
            }
            for (GiteaIssueComment comment : gitea.getComments(subscription.repoOwner(), subscription.repo(), subscription.issue())) {
                if (comment.id > subscription.issueComment()) {
                    reply.accept(comment.body, issue.title);
                    db.updateSubscriptionIssueComment(subscription.id(), comment.id);
                }
            }
        });
    }

    private void processEmails() throws SQLException, MessagingException, IOException {
        String[] addressParts = mail.getAddress().split("@");
        for (WrappedMessage message : mail.getInbox()) {
            try {
                String[] args = message.getRecipientSubAddress().split("\\+");
                switch (args[0]) {
                    case "create" -> {
                        if (args.length != 3) throw new UnexpectedMailException("Create classifier only allows two parameters");
                        String owner = args[1];
                        String repo = args[2];
                        checkArgs(owner, repo);
                        GiteaIssue issue = gitea.createIssue(owner, repo, message.getSubject(), formatBody(message));
                        String id = db.addSubscription(message.getSender(), owner, repo, issue.id, 0, message.getSender());
                        String unsubscribeUrl = web.getAddress() + "/unsubscribe?id=" + id; //TODO test
                        message.reply(addressParts[0] + "+reply+" + owner + "+" + repo + "+" + issue.id, MAIL_CREATE.formatted(issue.url, unsubscribeUrl));
                    }
                    case "reply" -> {
                        if (args.length != 2) throw new UnexpectedMailException("Reply classifier only allows one parameter");
                        Subscription sub = db.getSubscription(args[1]).orElseThrow(() -> new UnexpectedMailException("Reply classifier does not represent an active issue"));
                        GiteaIssueComment commentId = gitea.addComment(sub.repoOwner(), sub.repo(), sub.issue(), formatBody(message));
                        db.updateSubscriptionIssueComment(sub.id(), commentId.id);
                        db.updateSubscriptionReferenceChain(sub.id(), sub.referenceChain() + " " + message.getSender());
                    }
                    case "comment" -> {
                        if (args.length == 4) throw new UnexpectedMailException("Comment classifier requires four parameters");
                        String owner = args[1];
                        String repo = args[2];
                        long issueId = Long.parseLong(args[3]);
                        checkArgs(owner, repo);
                        GiteaIssue issue;
                        try {
                            issue = gitea.getIssue(owner, repo, issueId);
                        } catch (FileNotFoundException fe) {
                            throw new UnexpectedMailException("This issue does not exist");
                        }
                        gitea.addComment(owner, repo, issueId, formatBody(message));
                        if (issue.state.equals("closed")) {
                            message.reply(addressParts[0] + "+reply+" + owner + "+" + repo + "+" + issue.id, MAIL_COMMENT_CLOSED.formatted(issue.url));
                        } else {
                            String id = db.addSubscription(message.getSender(), owner, repo, issue.id, 0, message.getSender());
                            String unsubscribeUrl = web.getAddress() + "/unsubscribe?id=" + id; //TODO test
                            message.reply(addressParts[0] + "+reply+" + owner + "+" + repo + "+" + issue.id, MAIL_COMMENT.formatted(issue.url, unsubscribeUrl));
                        }
                    }
                    default -> throw new UnexpectedMailException("Did not expect classifier " + args[0]);
                }
            } catch (UnexpectedMailException | NumberFormatException t) {
                message.reply(mail.getAddress(), MAIL_UNEXPECTED.formatted(WebInterface.escapeHTML(StringFormatter.toString(t))));
            } catch (Throwable t) {
                Main.LOG.error("Could not parse mail", t);
                message.reply(mail.getAddress(), MAIL_ERROR.formatted(WebInterface.escapeHTML(StringFormatter.toString(t))));
            }
        }
    }

    private void checkArgs(String owner, String repo) throws UnexpectedMailException {
        //TODO document this limitation
        if (!Main.ALPHANUMERIC_PATTERN.matcher(owner).matches()) throw new UnexpectedMailException("Unsupported owner string");
        if (!Main.ALPHANUMERIC_PATTERN.matcher(repo).matches()) throw new UnexpectedMailException("Unsupported repo string");
    }

    private String formatBody(WrappedMessage message) throws UnexpectedMailException, MessagingException, IOException {
        return "Submitted by " + message.getSenderName() + ":\n\n" + message.getText();
    }
}