import {
  actionLabel,
  activeStatusById,
  applyFilterAndSort,
  applyGameTransferStatusSnapshot,
  canStreamInstall,
  countByFilter,
  deriveState,
  downloadProgressPercent,
  formatBytesPerSecond,
  formatDownloadBytes,
  formatDownloadEta,
  formatDownloadSpeed,
  formatDownloadSpeedShort,
  gameStatusLabel,
  mergeGameUpdate,
  primaryActionFor,
  stateChipLabel,
} from "../src/lib/gameState.ts";
import {
  ActiveOperationKind,
  type Game,
  GameAvailability,
  type GameFilter,
  GameTransferStatus,
  InstallStatus,
} from "../src/lib/types.ts";

const assertEquals = <T>(actual: T, expected: T, message: string) => {
  if (actual !== expected) {
    throw new Error(`${message}: expected ${expected}, got ${actual}`);
  }
};

const game = (overrides: Partial<Game> = {}): Game => ({
  id: "game",
  name: "Game",
  description: "",
  size: 0,
  downloaded: false,
  installed: false,
  availability: GameAvailability.LocalOnly,
  install_status: InstallStatus.NotInstalled,
  peer_count: 1,
  ...overrides,
});

Deno.test("snapshot keeps installing visible until installed state settles", () => {
  const fromDownloading = game({
    install_status: InstallStatus.Downloading,
  });
  const installing = mergeGameUpdate(
    game({ downloaded: true }),
    fromDownloading,
    InstallStatus.Installing,
  );
  const installedWhileActive = mergeGameUpdate(
    game({ downloaded: true, installed: true }),
    installing,
    InstallStatus.Installing,
  );
  const settled = mergeGameUpdate(
    game({ downloaded: true, installed: true }),
    installedWhileActive,
  );

  assertEquals(
    installing.install_status,
    InstallStatus.Installing,
    "active install snapshot should render Installing",
  );
  assertEquals(
    installedWhileActive.install_status,
    InstallStatus.Installing,
    "installed local state should not override an active install snapshot",
  );
  assertEquals(
    settled.install_status,
    InstallStatus.Installed,
    "cleared active snapshot with installed local state should render Installed",
  );
});

Deno.test("active operation snapshot is the source of busy status", () => {
  const statuses = activeStatusById([
    { id: "game", operation: ActiveOperationKind.Downloading },
    { id: "other", operation: ActiveOperationKind.Updating },
  ]);

  assertEquals(
    statuses.get("game"),
    InstallStatus.Downloading,
    "download operation should render Downloading",
  );
  assertEquals(
    statuses.get("other"),
    InstallStatus.Installing,
    "update operation should render Installing",
  );
});

const assertFilterMembership = (
  current: Game,
  expected: Record<GameFilter, number>,
) => {
  const counts = countByFilter([current]);
  for (const filter of ["all", "local", "installed"] as const) {
    assertEquals(
      applyFilterAndSort([current], filter, "az", "").length,
      expected[filter],
      `${current.install_status} visibility in ${filter}`,
    );
    assertEquals(counts[filter], expected[filter], `${filter} count`);
  }
};

Deno.test("offline local install stays visible through withdrawal and settlement", () => {
  const local = game({ downloaded: true, peer_count: 0 });
  const active = mergeGameUpdate(local, local, InstallStatus.Installing);
  // The peer withdraws shareable local state while staging the installation.
  const withdrawn = mergeGameUpdate(
    game({ peer_count: 0 }),
    active,
    InstallStatus.Installing,
  );
  for (const current of [local, active, withdrawn]) {
    assertFilterMembership(current, { all: 1, local: 1, installed: 0 });
  }
  assertEquals(
    withdrawn.downloaded,
    false,
    "keep backend availability truthful",
  );
  assertEquals(stateChipLabel(withdrawn), "Installing", "card status chip");
  assertEquals(gameStatusLabel(withdrawn), "Installing…", "detail status");
  assertEquals(actionLabel(withdrawn), "Installing…", "action label");
  assertEquals(
    primaryActionFor(withdrawn),
    "busy",
    "disable duplicate installs",
  );
  assertEquals(
    applyFilterAndSort([withdrawn], "all", "az", "unrelated").length,
    0,
    "busy cards still obey search",
  );

  const settled = mergeGameUpdate(
    game({ downloaded: true, installed: true, peer_count: 0 }),
    withdrawn,
  );
  assertFilterMembership(settled, { all: 1, local: 1, installed: 1 });
  assertEquals(
    actionLabel(settled),
    "Play",
    "successful install becomes playable",
  );

  const failed = mergeGameUpdate(local, withdrawn);
  assertFilterMembership(failed, { all: 1, local: 1, installed: 0 });
  assertEquals(actionLabel(failed), "Install", "failed install can be retried");
});

Deno.test("stream install remains local after its last source leaves", () => {
  const active = mergeGameUpdate(game(), game(), InstallStatus.Installing);
  const withdrawn = mergeGameUpdate(
    game({ peer_count: 0 }),
    active,
    InstallStatus.Installing,
  );
  assertFilterMembership(withdrawn, { all: 1, local: 1, installed: 0 });

  const settled = mergeGameUpdate(game({ peer_count: 0 }), withdrawn);
  assertFilterMembership(settled, { all: 0, local: 0, installed: 0 });
});

Deno.test("installed filter retains busy games until authoritative settlement", () => {
  for (
    const operation of [
      ActiveOperationKind.Downloading,
      ActiveOperationKind.Updating,
      ActiveOperationKind.Uninstalling,
    ]
  ) {
    const installed = game({
      downloaded: true,
      installed: true,
      peer_count: 0,
    });
    const activeStatus = activeStatusById([{ id: "game", operation }]).get(
      "game",
    );
    const active = mergeGameUpdate(installed, installed, activeStatus);
    const withdrawn = mergeGameUpdate(
      game({ peer_count: 0 }),
      active,
      activeStatus,
    );
    const repeated = mergeGameUpdate(
      game({ peer_count: 0 }),
      withdrawn,
      activeStatus,
    );
    for (const current of [active, withdrawn, repeated]) {
      assertFilterMembership(current, { all: 1, local: 1, installed: 1 });
    }
    assertEquals(
      repeated.installed,
      false,
      "filter pin must not imply playable state",
    );
    assertEquals(
      primaryActionFor(repeated),
      "busy",
      "operation stays disabled",
    );

    const settled = mergeGameUpdate(
      game({ downloaded: true, peer_count: 0 }),
      repeated,
    );
    assertFilterMembership(settled, { all: 1, local: 1, installed: 0 });
    assertEquals(
      settled.installed_before_operation,
      undefined,
      "clear prior membership",
    );
    const nextInstall = mergeGameUpdate(
      settled,
      settled,
      InstallStatus.Installing,
    );
    assertFilterMembership(nextInstall, { all: 1, local: 1, installed: 0 });
  }
});

Deno.test("local removal stays visible with its operation label until settled", () => {
  const local = game({ downloaded: true, peer_count: 0 });
  const active = mergeGameUpdate(local, local, InstallStatus.Removing);
  const withdrawn = mergeGameUpdate(
    game({ peer_count: 0 }),
    active,
    InstallStatus.Removing,
  );
  assertFilterMembership(withdrawn, { all: 1, local: 1, installed: 0 });
  assertEquals(stateChipLabel(withdrawn), "Removing", "card status chip");
  assertEquals(gameStatusLabel(withdrawn), "Removing…", "detail status");
  assertFilterMembership(
    mergeGameUpdate(game({ peer_count: 0 }), withdrawn),
    { all: 0, local: 0, installed: 0 },
  );
});

Deno.test("download progress is preserved only while actively downloading", () => {
  const downloading = game({
    install_status: InstallStatus.Downloading,
    download_progress: {
      attemptId: "1",
      downloaded_bytes: 50,
      total_bytes: 100,
      bytes_per_second: 12_500_000,
      active_peer_count: 2,
    },
  });

  const stillDownloading = mergeGameUpdate(
    game(),
    downloading,
    InstallStatus.Downloading,
  );
  const settled = mergeGameUpdate(game({ downloaded: true }), stillDownloading);

  assertEquals(
    stillDownloading.download_progress?.downloaded_bytes,
    50,
    "active download snapshot should keep progress",
  );
  assertEquals(
    stillDownloading.download_progress?.active_peer_count,
    2,
    "active download snapshot should keep live peer count",
  );
  assertEquals(
    settled.download_progress,
    undefined,
    "settled snapshot should clear progress",
  );
});

Deno.test("downloading action label includes current speed", () => {
  const downloading = game({
    install_status: InstallStatus.Downloading,
    download_progress: {
      attemptId: "1",
      downloaded_bytes: 50,
      total_bytes: 100,
      bytes_per_second: 12_500_000,
      active_peer_count: 2,
    },
  });

  assertEquals(
    formatBytesPerSecond(12_500_000),
    "12.5 MB/s",
    "speed formatter should use compact decimal units",
  );
  assertEquals(
    actionLabel(downloading),
    "Downloading… 12.5 MB/s",
    "download label should include speed",
  );
});

Deno.test("downloading state is distinct and stays on the local filter", () => {
  const downloading = game({
    id: "downloading",
    name: "Downloading",
    install_status: InstallStatus.Downloading,
  });
  const local = game({
    id: "local",
    name: "Local",
    downloaded: true,
  });
  const remote = game({
    id: "remote",
    name: "Remote",
    peer_count: 1,
  });

  assertEquals(
    deriveState(downloading),
    "downloading",
    "download operation should render the dedicated downloading state",
  );
  assertEquals(
    countByFilter([downloading, local, remote]).local,
    2,
    "local filter count should include in-flight downloads",
  );
  assertEquals(
    applyFilterAndSort([downloading, local, remote], "local", "status", "")
      .length,
    2,
    "local filter should include in-flight downloads",
  );
});

Deno.test("sticky transfer exhaustion keeps a departed remote game visible until cleared", () => {
  const remoteOnly = game({
    id: "remote-only",
    name: "Remote only",
    peer_count: 1,
  });
  assertEquals(
    applyFilterAndSort([remoteOnly], "all", "az", "").length,
    1,
    "a remote-only game should initially be visible",
  );

  const peerDeparted = mergeGameUpdate(
    game({ id: "remote-only", name: "Remote only", peer_count: 0 }),
    remoteOnly,
  );
  assertEquals(
    peerDeparted.install_status,
    InstallStatus.NotInstalled,
    "an empty active-operation snapshot should leave the game idle",
  );
  assertEquals(
    peerDeparted.peer_count,
    0,
    "the sole remote source should be absent from the next catalog snapshot",
  );
  assertEquals(
    applyFilterAndSort([peerDeparted], "all", "az", "").length,
    0,
    "an idle remote-only game should be invisible before exhaustion arrives",
  );

  const [exhausted] = applyGameTransferStatusSnapshot([peerDeparted], {
    revision: 1,
    statuses: { "remote-only": GameTransferStatus.Exhausted },
    openAttempts: {},
  });
  assertEquals(
    exhausted.transfer_status,
    GameTransferStatus.Exhausted,
    "the sticky snapshot should preserve the exact terminal status",
  );
  assertEquals(
    applyFilterAndSort([exhausted], "all", "az", "").length,
    1,
    "terminal exhaustion should keep the departed remote game visible",
  );
  assertEquals(
    countByFilter([exhausted]).all,
    1,
    "the All-filter count should match terminal exhaustion visibility",
  );

  const [cleared] = applyGameTransferStatusSnapshot([exhausted], {
    revision: 2,
    statuses: {},
    openAttempts: {},
  });
  assertEquals(
    cleared.transfer_status,
    undefined,
    "a full replacement that omits the game should clear exhaustion",
  );
  assertEquals(
    applyFilterAndSort([cleared], "all", "az", "").length,
    0,
    "clearing exhaustion should remove the otherwise-invisible game",
  );
});

Deno.test("transient transfer activity does not resurrect an invisible game", () => {
  const departed = game({ peer_count: 0 });
  for (
    const transferStatus of [
      GameTransferStatus.Verifying,
      GameTransferStatus.Retrying,
    ]
  ) {
    assertEquals(
      applyFilterAndSort(
        [{ ...departed, transfer_status: transferStatus }],
        "all",
        "az",
        "",
      ).length,
      0,
      `${transferStatus} should not make an otherwise-invisible game visible`,
    );
  }
});

Deno.test("download progress formatting matches the progress-bar layouts", () => {
  const downloading = game({
    install_status: InstallStatus.Downloading,
    download_progress: {
      attemptId: "1",
      downloaded_bytes: 12 * 1024 * 1024 * 1024,
      total_bytes: 35 * 1024 * 1024 * 1024,
      bytes_per_second: 49_400_000,
      active_peer_count: 3,
    },
  });

  assertEquals(
    Math.round(downloadProgressPercent(downloading)),
    34,
    "progress percent should come from backend byte counters",
  );
  assertEquals(
    formatDownloadSpeed(49_400_000),
    "49.4 MB/s",
    "large bar speed format",
  );
  assertEquals(
    formatDownloadSpeedShort(49_400_000),
    "49 MB/s",
    "card speed format",
  );
  assertEquals(
    formatDownloadBytes(12 * 1024 * 1024 * 1024),
    "12 GB",
    "downloaded byte format should avoid noisy trailing decimals",
  );
  assertEquals(
    formatDownloadEta(485),
    "8 min",
    "eta format should stay compact",
  );
});

Deno.test("stream install is available only for idle remote games", () => {
  assertEquals(
    canStreamInstall(
      game({ downloaded: false, installed: false, peer_count: 1 }),
      true,
    ),
    true,
    "catalog-supported remote-only idle games should allow streamed install",
  );
  assertEquals(
    canStreamInstall(
      game({ downloaded: false, installed: false, peer_count: 1 }),
      false,
    ),
    false,
    "catalog-unsupported games should not expose streamed install",
  );
  assertEquals(
    canStreamInstall(
      game({ downloaded: true, installed: false, peer_count: 1 }),
      true,
    ),
    false,
    "downloaded games should install from local archives",
  );
  assertEquals(
    canStreamInstall(
      game({ downloaded: false, installed: true, peer_count: 1 }),
      true,
    ),
    false,
    "installed games should not expose streamed install",
  );
  assertEquals(
    canStreamInstall(
      game({ downloaded: false, installed: false, peer_count: 0 }),
      true,
    ),
    false,
    "games without peers should not expose streamed install",
  );
  assertEquals(
    canStreamInstall(
      game({
        downloaded: false,
        installed: false,
        peer_count: 1,
        install_status: InstallStatus.Installing,
      }),
      true,
    ),
    false,
    "busy games should not expose streamed install",
  );
});

Deno.test("streamed local installs are labeled installed but not shareable", () => {
  const streamed = game({
    downloaded: false,
    installed: true,
    install_status: InstallStatus.Installed,
  });
  const downloadedInstall = game({
    downloaded: true,
    installed: true,
    install_status: InstallStatus.Installed,
  });

  assertEquals(
    deriveState(streamed),
    "installed",
    "streamed local installs should keep installed visual state",
  );
  assertEquals(
    stateChipLabel(streamed),
    "Not shareable",
    "card chip should make the non-shareable state visible",
  );
  assertEquals(
    gameStatusLabel(streamed),
    "Installed, not shareable",
    "detail status should spell out installed plus non-shareable",
  );
  assertEquals(
    stateChipLabel(downloadedInstall),
    "Installed",
    "normal downloaded installs should keep the installed chip label",
  );
  assertEquals(
    gameStatusLabel(downloadedInstall),
    "Installed",
    "normal downloaded installs should keep the installed detail label",
  );
});