import { IS_LINUX } from '../utils/platform';
import { sanitizeHiResCrossfadeResampleHz } from '../utils/audio/hiResCrossfadeResample';
import {
  sanitizeAutodjOverlapCapMode,
  sanitizeAutodjOverlapCapSec,
} from '../utils/playback/autodjOverlapCap';
import {
  LOUDNESS_PRE_ANALYSIS_REF_TARGET_LUFS,
  clampStoredLoudnessPreAnalysisAttenuationRefDb,
} from '../utils/audio/loudnessPreAnalysisSlider';
import { DEFAULT_LOUDNESS_PRE_ANALYSIS_ATTENUATION_DB } from './authStoreDefaults';
import {
  clampMixFilterMinStars,
  clampRandomMixSize,
  clampLibraryGridMaxColumns,
  sanitizeLoudnessLufsPreset,
  sanitizeLoudnessPreAnalysisFromStorage,
  sanitizeSkipStarCounts,
} from './authStoreHelpers';
import type {
  AuthState,
  DiscordCoverSource,
  DurationMode,
  LyricsSourceConfig,
  QueueDisplayMode,
  SeekbarStyle,
  WindowButtonStyle,
} from './authStoreTypes';
import { migrateLegacyLastfm, sanitizeAccounts } from '../music-network';

/**
 * Computes the post-rehydration patch for the auth store. Runs all
 * legacy-shape migrations + numeric sanitization that the persist
 * middleware can't express declaratively. The caller (the store's
 * `onRehydrateStorage` callback) applies the returned partial via
 * `useAuthStore.setState`.
 *
 * Side effects this function takes: deletes obsolete legacy fields
 * directly off the rehydrated state object (`animationMode`,
 * `reducedAnimations`) so they don't sit as cruft in localStorage,
 * and writes the one-shot Linux smooth-scroll migration sentinel.
 */
export function computeAuthStoreRehydration(state: AuthState): Partial<AuthState> {
  // Drop removed preload-next-track settings from legacy persist blobs.
  delete (state as { preloadMode?: unknown }).preloadMode;
  delete (state as { preloadCustomSeconds?: unknown }).preloadCustomSeconds;

  // Migrate lyricsServerFirst + enableNeteaselyrics → lyricsSources (one-time).
  // Only for an *existing* persisted state (upgrade from a build without
  // lyricsSources). Fresh installs have no persisted state → keep the
  // all-off default (issue #810); don't resurrect the old on-by-default set.
  let lyricsSourcesMigrated: { lyricsSources?: LyricsSourceConfig[] } = {};
  try {
    const raw = JSON.parse(localStorage.getItem('psysonic-auth') ?? '{}') as { state?: Record<string, unknown> };
    if (raw?.state && !raw.state.lyricsSources) {
      const serverFirst = (raw?.state?.lyricsServerFirst as boolean | undefined) ?? true;
      const neteaseOn   = (raw?.state?.enableNeteaselyrics as boolean | undefined) ?? false;
      const migrated: LyricsSourceConfig[] = serverFirst
        ? [{ id: 'server', enabled: true }, { id: 'lrclib', enabled: true }, { id: 'netease', enabled: neteaseOn }]
        : [{ id: 'lrclib', enabled: true }, { id: 'server', enabled: true }, { id: 'netease', enabled: neteaseOn }];
      lyricsSourcesMigrated = { lyricsSources: migrated };
    }
  } catch { /* ignore */ }

  // Migrate legacy `lyricsMode` ('standard' | 'lyricsplus') → `youLyPlusEnabled`
  // (one-time). Existing users keep YouLyPlus on iff they were on lyricsplus
  // mode; the legacy field is then stripped so it doesn't sit as cruft.
  let youLyPlusMigrated: { youLyPlusEnabled?: boolean } = {};
  const legacyLyricsMode = (state as { lyricsMode?: unknown }).lyricsMode;
  if (legacyLyricsMode === 'lyricsplus' || legacyLyricsMode === 'standard') {
    youLyPlusMigrated = { youLyPlusEnabled: legacyLyricsMode === 'lyricsplus' };
  }
  delete (state as { lyricsMode?: unknown }).lyricsMode;

  // One-time: older builds could persist smooth=false as the default. Force smooth on once
  // so updates do not leave users on discrete scrolling; after this flag exists, only an
  // explicit toggle in Settings may turn it off (persisted in psysonic-auth).
  const wheelSmoothMigrationKey = 'psysonic-linux-webkit-smooth-v1';
  let wheelSmoothOneTime: { linuxWebkitKineticScroll?: boolean } = {};
  if (IS_LINUX) {
    try {
      if (!localStorage.getItem(wheelSmoothMigrationKey)) {
        wheelSmoothOneTime = { linuxWebkitKineticScroll: true };
        localStorage.setItem(wheelSmoothMigrationKey, '1');
      }
    } catch { /* ignore */ }
  }

  // 'waveform' style was renamed to 'truewave' (with 'pseudowave' added
  // as the deterministic legacy variant). Any persisted value that is
  // not a valid SeekbarStyle (legacy 'waveform', undefined, tampered
  // strings) lands on the new bins-based default — otherwise the
  // dispatcher's switch finds no match and the seekbar renders blank.
  const VALID_SEEKBAR_STYLES = new Set<string>([
    'truewave', 'pseudowave', 'linedot', 'bar', 'thick',
    'segmented', 'neon', 'pulsewave', 'particletrail', 'liquidfill', 'retrotape',
  ]);
  const seekbarStyleMigrated = VALID_SEEKBAR_STYLES.has(state.seekbarStyle as string)
    ? {}
    : { seekbarStyle: 'truewave' as SeekbarStyle };

  // Unknown / missing / tampered window-button style falls back to the
  // default 'dots' so the title bar never renders an unstyled data-attr.
  const VALID_WINDOW_BUTTON_STYLES = new Set<string>([
    'dots', 'dotsGlyph', 'flat', 'pill', 'outline', 'glyph',
  ]);
  const windowButtonStyleMigrated = VALID_WINDOW_BUTTON_STYLES.has(
    (state as { windowButtonStyle?: unknown }).windowButtonStyle as string,
  )
    ? {}
    : { windowButtonStyle: 'dots' as WindowButtonStyle };

  // Garbage / null / undefined / missing key from a legacy or tampered persist
  // payload maps back to 'total' so the duration chip never receives an
  // unknown mode (would render an empty label).
  const VALID_QUEUE_DURATION_MODES = new Set<string>(['total', 'remaining', 'eta']);
  const queueDurationDisplayModeMigrated = VALID_QUEUE_DURATION_MODES.has(
    (state as { queueDurationDisplayMode?: unknown }).queueDurationDisplayMode as string,
  )
    ? {}
    : { queueDurationDisplayMode: 'total' as DurationMode };

  // Missing key (pre-feature persist) / garbage maps to 'queue' — the default
  // mode, which lists only upcoming tracks.
  const VALID_QUEUE_DISPLAY_MODES = new Set<string>(['playlist', 'queue', 'timeline']);
  const queueDisplayModeMigrated = VALID_QUEUE_DISPLAY_MODES.has(
    (state as { queueDisplayMode?: unknown }).queueDisplayMode as string,
  )
    ? {}
    : { queueDisplayMode: 'queue' as QueueDisplayMode };

  const VALID_WAYLAND_TEXT_PROFILE = new Set<string>(['balanced', 'sharp', 'gpu', 'minimal']);
  const rawWaylandProfile = (state as { linuxWaylandTextRenderProfile?: unknown }).linuxWaylandTextRenderProfile;
  const linuxWaylandTextRenderProfileMigrated = VALID_WAYLAND_TEXT_PROFILE.has(rawWaylandProfile as string)
    ? {}
    : { linuxWaylandTextRenderProfile: 'sharp' as const };

  // The `animationMode` 3-state setting was removed; users on `'reduced'`
  // or `'static'` collapse onto the former `'full'` path automatically as
  // soon as the field is gone from the store. Strip the persisted field
  // so it doesn't sit in localStorage as cruft.
  delete (state as { animationMode?: unknown }).animationMode;
  // The earlier `reducedAnimations: boolean` predecessor likewise loses
  // its meaning; clear it for the same reason.
  delete (state as { reducedAnimations?: unknown }).reducedAnimations;

  const st = state as {
    loudnessTargetLufs?: unknown;
    loudnessPreAnalysisAttenuationDb?: unknown;
    loudnessPreIsRefV1?: unknown;
  };
  const targetSan = sanitizeLoudnessLufsPreset(st.loudnessTargetLufs, -12);
  const rawN = st.loudnessPreAnalysisAttenuationDb;
  const n = typeof rawN === 'number' ? rawN : Number(rawN);
  const preSan =
    st.loudnessPreIsRefV1 === true
      ? sanitizeLoudnessPreAnalysisFromStorage(rawN)
      : (Number.isFinite(n)
          ? clampStoredLoudnessPreAnalysisAttenuationRefDb(
              n - (targetSan - LOUDNESS_PRE_ANALYSIS_REF_TARGET_LUFS),
            )
          : DEFAULT_LOUDNESS_PRE_ANALYSIS_ATTENUATION_DB);

  // Migrate enableAppleMusicCoversDiscord boolean → discordCoverSource enum.
  let discordCoverSourceMigrated: { discordCoverSource?: DiscordCoverSource } = {};
  const legacyAppleCovers = (state as { enableAppleMusicCoversDiscord?: unknown }).enableAppleMusicCoversDiscord;
  if (legacyAppleCovers === true && (!state.discordCoverSource || state.discordCoverSource === 'none')) {
    discordCoverSourceMigrated = { discordCoverSource: 'apple' };
  }

  // One-time: legacy unified `maxCacheMb` cap removed from Settings (offline + IDB covers).
  const maxCacheMbMigrationKey = 'psysonic-max-cache-mb-removed-v1';
  let maxCacheMbMigrated: { maxCacheMb?: number } = {};
  try {
    if (!localStorage.getItem(maxCacheMbMigrationKey)) {
      maxCacheMbMigrated = { maxCacheMb: 0 };
      localStorage.setItem(maxCacheMbMigrationKey, '1');
    }
  } catch { /* ignore */ }

  // Music Network: one-time migration of the legacy flat lastfm* fields into the
  // accounts[] model. Runs exactly once (guarded by a sentinel) so a later
  // disconnect can't resurrect the account from the still-present legacy fields.
  // Subsequent rehydrates only sanitize the persisted account list.
  const musicNetworkMigrationKey = 'psysonic-music-network-migrated-v1';
  let musicNetworkMigrated: Partial<AuthState> = {
    musicNetworkAccounts: sanitizeAccounts(
      (state as { musicNetworkAccounts?: unknown }).musicNetworkAccounts,
    ),
  };
  try {
    if (!localStorage.getItem(musicNetworkMigrationKey)) {
      // The legacy lastfm* fields no longer exist on AuthState; read them off the
      // persisted blob (present on upgrade) via a cast.
      const legacy = state as unknown as {
        lastfmSessionKey?: string;
        lastfmUsername?: string;
        scrobblingEnabled?: boolean;
      };
      const migrated = migrateLegacyLastfm(
        {
          lastfmSessionKey: legacy.lastfmSessionKey,
          lastfmUsername: legacy.lastfmUsername,
          scrobblingEnabled: legacy.scrobblingEnabled,
        },
        () => crypto.randomUUID(),
      );
      musicNetworkMigrated = {
        musicNetworkAccounts: migrated.accounts,
        enrichmentPrimaryId: migrated.enrichmentPrimaryId,
        scrobblingMasterEnabled: migrated.scrobblingMasterEnabled,
      };
      localStorage.setItem(musicNetworkMigrationKey, '1');
    }
  } catch { /* ignore */ }

  // Strip the legacy flat lastfm* fields from the persisted blob (spec §6.1.3).
  // The migration above maps them into accounts[]; the sentinel guards
  // re-migration, so these now sit as pure cruft. Drop them on every rehydrate.
  for (const k of ['lastfmApiKey', 'lastfmApiSecret', 'lastfmSessionKey', 'lastfmUsername', 'lastfmSessionError', 'scrobblingEnabled']) {
    delete (state as unknown as Record<string, unknown>)[k];
  }

  let mediaDirMigrated: { mediaDir?: string } = {};
  const stMedia = state as { mediaDir?: unknown; offlineDownloadDir?: string; hotCacheDownloadDir?: string };
  if (!stMedia.mediaDir || (typeof stMedia.mediaDir === 'string' && stMedia.mediaDir.trim() === '')) {
    const offline = (stMedia.offlineDownloadDir ?? '').trim();
    const hot = (stMedia.hotCacheDownloadDir ?? '').trim();
    if (offline && (!hot || offline === hot)) {
      mediaDirMigrated = { mediaDir: offline };
    } else if (hot) {
      mediaDirMigrated = { mediaDir: hot };
    }
  }

  return {
    ...mediaDirMigrated,
    ...musicNetworkMigrated,
    mixMinRatingSong: clampMixFilterMinStars(state.mixMinRatingSong as number),
    mixMinRatingAlbum: clampMixFilterMinStars(state.mixMinRatingAlbum as number),
    mixMinRatingArtist: clampMixFilterMinStars(state.mixMinRatingArtist as number),
    randomMixSize: clampRandomMixSize(state.randomMixSize as number),
    libraryGridMaxColumns: clampLibraryGridMaxColumns(
      (state as { libraryGridMaxColumns?: unknown }).libraryGridMaxColumns,
    ),
    skipStarManualSkipCountsByKey: sanitizeSkipStarCounts(
      (state as { skipStarManualSkipCountsByKey?: unknown }).skipStarManualSkipCountsByKey,
    ),
    loudnessTargetLufs: targetSan,
    loudnessPreAnalysisAttenuationDb: preSan,
    loudnessPreIsRefV1: true,
    hiResCrossfadeResampleHz: sanitizeHiResCrossfadeResampleHz(
      (state as { hiResCrossfadeResampleHz?: unknown }).hiResCrossfadeResampleHz,
    ),
    autodjOverlapCapMode: sanitizeAutodjOverlapCapMode(
      (state as { autodjOverlapCapMode?: unknown }).autodjOverlapCapMode,
    ),
    autodjOverlapCapSec: sanitizeAutodjOverlapCapSec(
      (state as { autodjOverlapCapSec?: unknown }).autodjOverlapCapSec,
    ),
    ...lyricsSourcesMigrated,
    ...youLyPlusMigrated,
    ...wheelSmoothOneTime,
    ...seekbarStyleMigrated,
    ...windowButtonStyleMigrated,
    ...queueDurationDisplayModeMigrated,
    ...queueDisplayModeMigrated,
    ...linuxWaylandTextRenderProfileMigrated,
    ...discordCoverSourceMigrated,
    ...maxCacheMbMigrated,
  };
}