import { useEffect, useState } from "react";
import { get } from "../api";
import { useT, type Key } from "../i18n";
import { Spinner } from "./Activity";
import { Icon } from "./Icon";

interface MediaItem {
  kind: "image" | "video" | "audio";
  url: string;
  name: string;
  source: "generated" | "tool" | "written" | "answer" | "upload";
  created_at: number;
  message_id?: string;
}

type Filter = "all" | MediaItem["kind"];

/**
 * All images, videos and audio files of a chat (with its subagents), newest first.
 * An item opens large; "show in chat" jumps to the message it came with.
 */
export function MediaGallery({ sessionId, onClose, onJump }: { sessionId: string; onClose: () => void; onJump: (messageId: string) => void }) {
  const t = useT();
  const [items, setItems] = useState<MediaItem[]>();
  const [error, setError] = useState<string>();
  const [filter, setFilter] = useState<Filter>("all");
  const [open, setOpen] = useState<number>();

  useEffect(() => {
    get<MediaItem[]>(`/sessions/${sessionId}/media`)
      .then(setItems)
      .catch((e) => setError(e.message));
  }, [sessionId]);

  const shown = (items ?? []).filter((i) => filter === "all" || i.kind === filter);
  const count = (k: Filter) => (items ?? []).filter((i) => k === "all" || i.kind === k).length;
  const current = open !== undefined ? shown[open] : undefined;

  // Keyboard: Esc closes, arrows step through the open item.
  useEffect(() => {
    const onKey = (e: KeyboardEvent) => {
      if (e.key === "Escape") return current ? setOpen(undefined) : onClose();
      if (current && e.key === "ArrowRight") setOpen((o) => Math.min((o ?? 0) + 1, shown.length - 1));
      if (current && e.key === "ArrowLeft") setOpen((o) => Math.max((o ?? 0) - 1, 0));
    };
    window.addEventListener("keydown", onKey);
    return () => window.removeEventListener("keydown", onKey);
  }, [current, shown.length, onClose]);

  return (
    <div className="modal-backdrop" onClick={onClose}>
      <div className="modal media-gallery" role="dialog" aria-label={t("media.title")} onClick={(e) => e.stopPropagation()}>
        <div className="media-head">
          <h3>
            <Icon name="image" /> {t("media.title")}
          </h3>
          <div className="media-filters" role="radiogroup">
            {(["all", "image", "video", "audio"] as Filter[]).map((k) => (
              <button key={k} role="radio" aria-checked={filter === k} className={`chip-btn ${filter === k ? "active" : ""}`} onClick={() => (setFilter(k), setOpen(undefined))} disabled={!!items && count(k) === 0 && k !== "all"}>
                {t(`media.filter.${k}` as Key)} {items && <small>{count(k)}</small>}
              </button>
            ))}
          </div>
          <button className="small ghost" onClick={onClose} aria-label={t("common.close")}>
            <Icon name="close" />
          </button>
        </div>
        {error && <div className="notice err">{error}</div>}
        {!items && !error && (
          <div className="empty">
            <Spinner />
          </div>
        )}
        {items && shown.length === 0 && <div className="empty">{t("media.none")}</div>}
        {current ? (
          <div className="media-viewer">
            <div className="media-stage">
              {current.kind === "image" && <img src={current.url} alt={current.name} />}
              {current.kind === "video" && <video src={current.url} controls autoPlay />}
              {current.kind === "audio" && <audio src={current.url} controls autoPlay />}
            </div>
            <div className="media-bar">
              <button className="small ghost" disabled={open === 0} onClick={() => setOpen((o) => (o ?? 1) - 1)} aria-label={t("media.prev")}>
                <Icon name="arrow-left" />
              </button>
              <span className="grow">
                {current.name} · {t(`media.source.${current.source}` as Key)} · {new Date(current.created_at).toLocaleString(undefined, { dateStyle: "short", timeStyle: "short" })}
              </span>
              {current.message_id && (
                <button className="small" onClick={() => onJump(current.message_id!)}>
                  {t("media.showInChat")}
                </button>
              )}
              <a className="small button" href={current.url} target="_blank" rel="noreferrer">
                <Icon name="external" /> {t("media.open")}
              </a>
              <button className="small ghost" disabled={open === shown.length - 1} onClick={() => setOpen((o) => (o ?? 0) + 1)} aria-label={t("media.next")}>
                <Icon name="arrow-right" />
              </button>
              <button className="small ghost" onClick={() => setOpen(undefined)} aria-label={t("media.back")}>
                <Icon name="close" />
              </button>
            </div>
          </div>
        ) : (
          <div className="media-grid">
            {shown.map((m, i) => (
              <button key={m.url} className={`media-tile ${m.kind}`} onClick={() => setOpen(i)} title={`${m.name} · ${t(`media.source.${m.source}` as Key)}`}>
                {m.kind === "image" && <img src={m.url} alt="" loading="lazy" decoding="async" />}
                {m.kind === "video" && <video src={`${m.url}#t=0.1`} preload="metadata" muted />}
                {m.kind === "audio" && (
                  <span className="media-audio">
                    <Icon name="music" />
                    <span>{m.name}</span>
                  </span>
                )}
                {m.kind === "video" && <Icon name="play" className="media-play" />}
              </button>
            ))}
          </div>
        )}
      </div>
    </div>
  );
}