"use client";

import type { ScheduleSlot } from "@/app/(main)/tv/components";
import type { ScheduledSlotResponse } from "@/lib/types";

// ---------------------------------------------------------------------------
// Pure transformation utilities
// ---------------------------------------------------------------------------

/** Format an ISO-8601 string to "HH:MM" in the user's local timezone. */
export function fmtTime(iso: string): string {
  return new Date(iso).toLocaleTimeString([], {
    hour: "2-digit",
    minute: "2-digit",
    hour12: false,
  });
}

/** Progress percentage through a slot based on wall-clock time. */
export function calcProgress(startAt: string, durationSecs: number): number {
  if (durationSecs <= 0) return 0;
  const elapsedSecs = (Date.now() - new Date(startAt).getTime()) / 1000;
  return Math.min(100, Math.max(0, Math.round((elapsedSecs / durationSecs) * 100)));
}

/**
 * Seconds elapsed since a slot started, computed from the current wall clock.
 * Use this instead of `broadcast.offset_secs` when the broadcast may be cached —
 * start_at is a fixed timestamp so the offset is always accurate regardless of
 * when the broadcast response was fetched.
 */
export function calcOffsetSecs(startAt: string): number {
  return Math.max(0, (Date.now() - new Date(startAt).getTime()) / 1000);
}

/** Minutes until a future timestamp (rounded, minimum 0). */
export function minutesUntil(iso: string): number {
  return Math.max(0, Math.round((new Date(iso).getTime() - Date.now()) / 60_000));
}

/**
 * Map EPG slots to the shape expected by ScheduleOverlay.
 * Marks the slot matching currentSlotId as current.
 */
export function toScheduleSlots(
  slots: ScheduledSlotResponse[],
  currentSlotId?: string,
): ScheduleSlot[] {
  return slots.map((slot) => {
    const item = slot.item;
    const isEpisode = item.content_type === "episode";

    // Headline: series name for episodes (fall back to episode title), film title otherwise
    const title = isEpisode && item.series_name ? item.series_name : item.title;

    // Subtitle: episode identifier + title, or year for films
    let subtitle: string | null = null;
    if (isEpisode) {
      const epParts: string[] = [];
      if (item.season_number != null) epParts.push(`S${item.season_number}`);
      if (item.episode_number != null) epParts.push(`E${item.episode_number}`);
      const epLabel = epParts.join(" · ");
      subtitle = item.series_name
        ? [epLabel, item.title].filter(Boolean).join(" · ")
        : epLabel || null;
    } else if (item.year) {
      subtitle = String(item.year);
    }

    const durationMins = Math.round(
      (new Date(slot.end_at).getTime() - new Date(slot.start_at).getTime()) / 60_000,
    );

    return {
      id: slot.id,
      title,
      subtitle,
      durationMins,
      startTime: fmtTime(slot.start_at),
      endTime: fmtTime(slot.end_at),
      isCurrent: slot.id === currentSlotId,
    };
  });
}

/**
 * Find the slot immediately after the current one.
 * Returns null if current slot is last or not found.
 */
export function findNextSlot(
  slots: ScheduledSlotResponse[],
  currentSlotId?: string,
): ScheduledSlotResponse | null {
  if (!currentSlotId || slots.length === 0) return null;
  const idx = slots.findIndex((s) => s.id === currentSlotId);
  if (idx === -1 || idx === slots.length - 1) return null;
  return slots[idx + 1];
}

// ---------------------------------------------------------------------------
// useStreamUrl — HLS playlist from the Playout Service
// ---------------------------------------------------------------------------

const PLAYOUT_URL =
  process.env.NEXT_PUBLIC_PLAYOUT_URL ?? "http://localhost:9090";

export function useStreamUrl(channelId: string | undefined) {
  if (!channelId) return { data: null, isLoading: false, error: null };
  return {
    data: `${PLAYOUT_URL}/playout/${channelId}/playlist.m3u8`,
    isLoading: false,
    error: null,
  };
}