export type ParsedStart = { hour: number; minute: number; second: number };

const START_RE = /^(\d{1,2}):([0-5]\d)(?::([0-5]\d))?$/;

export function parseStartTime(s?: string): ParsedStart | null {
    if (!s || typeof s !== "string") return null;
    const m = START_RE.exec(s.trim());
    if (!m) return null;
    const hour = Number(m[1]);
    const minute = Number(m[2]);
    const second = m[3] ? Number(m[3]) : 0;
    if (hour < 0 || hour > 23) return null;
    return { hour, minute, second };
}

export function parseDurationToSeconds(s?: string, fallback = 0): number {
    if (!s || typeof s !== "string") return fallback;
    const parts = s.trim().split(":").map(Number);
    if (parts.some((n) => Number.isNaN(n) || n < 0)) return fallback;
    if (parts.length === 2) {
        const [mm, ss] = parts;
        return mm * 60 + ss;
    } else if (parts.length === 3) {
        const [hh, mm, ss] = parts;
        return hh * 3600 + mm * 60 + ss;
    }
    return fallback;
}