import { Capacitor } from "@capacitor/core";
import { useMemo } from "react";
import {
  checkForContentUpdates,
  contentPackHasUpdate,
  contentPackIsBundled,
  contentPackIsInstalled,
  installContentPack,
  removeContentPack,
} from "../content/contentManager";
import { useContentManagerSnapshot } from "../content/useContentManager";
import { DualDisplayFrame } from "../components/DualDisplayFrame";
import { LazyLocalCompanionPanel } from "./LazyLocalCompanionPanel";
import { BrandMark, FrontSurface } from "./FrontSurface";

function formatBytes(bytes: number): string {
  if (bytes >= 1024 ** 3) return `${(bytes / 1024 ** 3).toFixed(2)} GB`;
  if (bytes >= 1024 ** 2) return `${(bytes / 1024 ** 2).toFixed(1)} MB`;
  if (bytes >= 1024) return `${(bytes / 1024).toFixed(1)} KB`;
  return `${bytes} B`;
}

export function ContentManagerScreen({ onClose }: { readonly onClose: () => void }) {
  const state = useContentManagerSnapshot();
  const native = Capacitor.isNativePlatform();
  const packs = useMemo(() => state.manifest?.packs ?? state.bundledManifest?.packs ?? [], [state.bundledManifest, state.manifest]);
  const progress = state.totalBytes > 0 ? Math.min(1, state.downloadedBytes / state.totalBytes) : 0;

  return (
    <DualDisplayFrame
      contextLabel="Downloaded content"
      top={
        <FrontSurface className="content-manager-screen" ariaLabel="Healer Man content manager">
          <header className="content-manager-header">
            <BrandMark compact />
            <div><span>Main menu / Downloads</span><strong>Offline content</strong></div>
            <button type="button" className="front-button" onClick={onClose}>Back</button>
          </header>
          <main className="content-manager-main">
            <section className="content-manager-summary">
              <p className="front-kicker">Local-first installation</p>
              <h1>Choose what stays on this device</h1>
              <p>
                Installed content packs work without a server connection. Updates download to a temporary staging area,
                verify their SHA-256, and only then replace the active version.
              </p>
              {!native && <p className="front-notice">Basic content is included. Optional packs can be downloaded for offline play and removed when you want the storage back.</p>}
              <div className="content-manager-summary__actions">
                <button type="button" className="front-button" disabled={state.checking} onClick={() => void checkForContentUpdates()}>
                  {state.checking ? "Checking..." : "Check for updates"}
                </button>
                <small>{state.manifest ? `Catalog ${state.manifest.version}` : "Offline catalog unavailable"}</small>
              </div>
              {state.installingPackId && (
                <div className="content-manager-progress" role="progressbar" aria-valuenow={Math.round(progress * 100)} aria-valuemin={0} aria-valuemax={100}>
                  <span style={{ width: `${progress * 100}%` }} />
                  <small>{formatBytes(state.downloadedBytes)} / {formatBytes(state.totalBytes)}</small>
                </div>
              )}
              {state.error && <p className="front-notice" role="alert">{state.error}</p>}
            </section>
            <section className="content-manager-packs" aria-label="Content packs">
              {packs.length === 0 && <p className="content-manager-empty">Connect once to discover optional downloads. Bundled starter content remains playable offline.</p>}
              {packs.map((pack) => {
                const installed = contentPackIsInstalled(pack.id);
                const update = contentPackHasUpdate(pack.id);
                const bundled = contentPackIsBundled(pack.id);
                const busy = state.installingPackId !== null;
                return (
                  <article key={pack.id} className="content-pack-row">
                    <div>
                      <strong>{pack.label}</strong>
                      <small>{formatBytes(pack.downloadBytes ?? pack.bytes)} download / {pack.fileCount} files</small>
                    </div>
                    <span className={installed ? "is-installed" : ""}>
                      {update ? "Update available" : bundled ? "Included — always available" : installed ? "Installed — offline ready" : "Not installed"}
                    </span>
                    <div className="content-pack-row__actions">
                      {(!installed || update) && (
                        <button type="button" className="front-button front-button--primary" disabled={busy} onClick={() => void installContentPack(pack.id).catch(() => undefined)}>
                          {state.installingPackId === pack.id ? "Downloading..." : update ? "Update" : "Download"}
                        </button>
                      )}
                      {installed && !bundled && (
                        <button type="button" className="front-button" disabled={busy} onClick={() => void removeContentPack(pack.id).catch(() => undefined)}>
                          Remove
                        </button>
                      )}
                    </div>
                  </article>
                );
              })}
            </section>
          </main>
        </FrontSurface>
      }
      bottom={<LazyLocalCompanionPanel />}
    />
  );
}