import { validTimeZone } from './time-zone.js';

export interface MaintenanceSchedule {
    enabled: boolean;
    time: string;
    timeZone: string;
    nextAt: string | null;
}
export interface PlutoniumRelease {
    revision: number | null;
    checkedAt: string | null;
    error: string | null;
}
export interface PlutoniumVersion {
    server: string;
    revision: number | null;
    checked_at: string | null;
    error: string | null;
    stopped?: boolean;
    update_status?: 'outdated' | 'current' | 'ahead' | 'unknown' | 'stopped';
}
export interface MaintenanceJob {
    id: number;
    server: string;
    server_deleted_at?: string | null;
    state: 'queued' | 'restarting' | 'done' | 'failed' | 'cancelled';
    target_revision: number | null;
    requested_at: string;
    restarted_at: string | null;
    provisioning_id: string | null;
    finished_at: string | null;
    detail: string | null;
    kind: 'legacy' | 'update' | 'schedule';
    origin: 'manual' | 'automatic' | 'schedule';
    operation_stage?: string | null;
    operation_state?: string | null;
}
export interface PlutoniumStatus {
    release: PlutoniumRelease;
    schedule: MaintenanceSchedule;
    servers: PlutoniumVersion[];
    jobs: MaintenanceJob[];
}

/** Accept explicit revision tokens only, never engine versions or build dates. */
export function parsePlutoniumRevision(text: string): number | null {
    const match = text.replace(/\^[0-9]/g, '').match(/\br([1-9]\d{2,8})\b/i);
    return match ? Number(match[1]) : null;
}

export const PLUTONIUM_MANIFEST_URL = 'https://cdn.plutoniummod.com/updater/prod/info.json';

export function parsePlutoniumManifest(value: unknown): number {
    const manifest = value as { product?: unknown; revision?: unknown } | null;
    if (!manifest || manifest.product !== 'plutonium-core-prod' || typeof manifest.revision !== 'number'
        || !Number.isSafeInteger(manifest.revision) || manifest.revision < 1) {
        throw new Error('The production updater manifest did not contain a valid Plutonium revision.');
    }
    return manifest.revision;
}

export function nextMaintenanceAt(time: string, now = new Date(), timeZone = 'UTC'): string {
    if (!/^([01]\d|2[0-3]):[0-5]\d$/.test(time)) throw new Error('Choose a valid time (HH:mm).');
    if (!validTimeZone(timeZone)) throw new Error('Choose a valid timezone.');
    if (!Number.isFinite(now.getTime())) throw new Error('Invalid schedule date.');
    const [hour, minute] = time.split(':').map(Number);
    const target = hour * 60 + minute;
    const formatter = new Intl.DateTimeFormat('en-CA', {
        timeZone, year: 'numeric', month: '2-digit', day: '2-digit',
        hour: '2-digit', minute: '2-digit', hourCycle: 'h23'
    });
    function local(at: number) {
        const parts = Object.fromEntries(formatter.formatToParts(at).map(p => [p.type, p.value]));
        return { day: `${parts.year}-${parts.month}-${parts.day}`, minute: Number(parts.hour) * 60 + Number(parts.minute) };
    }
    const today = local(now.getTime()).day;
    const start = Math.floor(now.getTime() / 60_000) * 60_000;
    const days = new Map<string, { at: number; minute: number }>();
    // Bounded minute search avoids assuming whole-hour offsets or 24-hour days.
    // A missing wall time runs at the first valid minute after the DST gap;
    // a repeated wall time runs only on its first occurrence that local day.
    for (let at = start - 26 * 3_600_000; at <= start + 50 * 3_600_000; at += 60_000) {
        const wall = local(at);
        if (wall.day < today || wall.minute < target) continue;
        const previous = days.get(wall.day);
        if (!previous || wall.minute < previous.minute) days.set(wall.day, { at, minute: wall.minute });
    }
    const next = [...days.values()].map(d => d.at).filter(at => at > now.getTime()).sort((a, b) => a - b)[0];
    if (next === undefined) throw new Error('Could not calculate the next maintenance time.');
    return new Date(next).toISOString();
}

/** Present an existing schedule in the viewing user's zone without rewriting it. */
export function maintenanceTimeInZone(schedule: MaintenanceSchedule, timeZone: string): string {
    if (schedule.timeZone === timeZone) return schedule.time;
    const at = schedule.nextAt ?? nextMaintenanceAt(schedule.time, new Date(), schedule.timeZone);
    return new Intl.DateTimeFormat('en-GB', { timeZone, hour: '2-digit', minute: '2-digit', hourCycle: 'h23' }).format(new Date(at));
}