//
// Timestamp helpers. Gitea returns RFC3339 strings and uses the Go zero time
// ("0001-01-01T00:00:00Z") to mean "never", which must not be shown as a date.
//

const ZERO_YEAR = 1;

function parse(value) {
    if (!value) return null;
    if (typeof value === "number") {
        // Gitea occasionally hands back Unix seconds for job timestamps.
        return value > 0 ? new Date(value * 1000) : null;
    }
    const date = new Date(value);
    if (Number.isNaN(date.getTime()) || date.getUTCFullYear() <= ZERO_YEAR) return null;
    return date;
}

function relative(value) {
    const date = parse(value);
    if (!date) return "";
    const seconds = Math.round((Date.now() - date.getTime()) / 1000);
    const future = seconds < 0;
    const abs = Math.abs(seconds);

    let text;
    if (abs < 45) text = "just now";
    else if (abs < 90) text = "a minute";
    else if (abs < 3600) text = `${Math.round(abs / 60)}m`;
    else if (abs < 86400) text = `${Math.round(abs / 3600)}h`;
    else if (abs < 2592000) text = `${Math.round(abs / 86400)}d`;
    else if (abs < 31536000) text = `${Math.round(abs / 2592000)}mo`;
    else text = `${Math.round(abs / 31536000)}y`;

    if (text === "just now") return text;
    return future ? `in ${text}` : `${text} ago`;
}

function duration(start, end) {
    const from = parse(start);
    if (!from) return "";
    const to = parse(end) || new Date();
    let seconds = Math.max(0, Math.round((to.getTime() - from.getTime()) / 1000));

    const hours = Math.floor(seconds / 3600);
    seconds -= hours * 3600;
    const minutes = Math.floor(seconds / 60);
    seconds -= minutes * 60;

    if (hours) return `${hours}h ${minutes}m`;
    if (minutes) return `${minutes}m ${seconds}s`;
    return `${seconds}s`;
}

function absolute(value) {
    const date = parse(value);
    if (!date) return "";
    return date.toLocaleString();
}

exports.parse = parse;
exports.relative = relative;
exports.duration = duration;
exports.absolute = absolute;