browser.tabs.onUpdated.addListener((tabId, changeInfo, tab) => {
    if (changeInfo.url) {
        groupTabs(tabId);
    }
});

const colors = [
    "blue",
    "cyan",
    "grey",
    "green",
    "orange",
    "pink",
    "purple",
    "red",
    "yellow",
];

async function groupTabs(tabId) {
    const tabs = await browser.tabs.query({ currentWindow: true });

    const domainGroups = {};
    const groupIds = [];

    for (let tab of tabs) {
        if (!groupIds.includes(tab.groupId)) {
            groupIds.push(tab.groupId);
        }

        const hostname = new URL(tab.url).hostname;

        const parts = hostname.split(".");

        let domain = parts[0];
        if (parts.length > 1) {
            parts.pop();
            if (parts[0] == "www") {
                parts.shift();
            }
            domain = toTitleCase(parts.join(" "));
        }

        if (domain == "") {
            domain = "Browser";
        }

        if (tab.groupId == -1 || tab.id == tabId || tab.active) {
            if (!domainGroups[domain]) {
                domainGroups[domain] = [];
            }
            domainGroups[domain].push(tab.id);
        }
    }

    for (const groupId in groupIds) {
        if (groupIds[groupId] != -1) {
            let tabGroup = await browser.tabGroups.get(groupIds[groupId]);

            if (tabGroup.title in domainGroups) {
                const updatedGroup = await browser.tabs.group({
                    tabIds: domainGroups[tabGroup.title],
                    groupId: tabGroup.id,
                });

                delete domainGroups[tabGroup.title];
            }
        }
    }

    for (const domain in domainGroups) {
        const groupId = await browser.tabs.group({
            tabIds: domainGroups[domain],
        });

        await browser.tabGroups.update(groupId, {
            title: domain,
            color: colors[groupId % colors.length],
        });
    }
}

function toTitleCase(str) {
    str = str.replace(/[-_]/g, " ");
    return str.replace(
        /\w(\S)*/g,
        (text) =>
            text.charAt(0).toUpperCase() + text.substring(1).toLowerCase(),
    );
}