import { create } from 'zustand';
import type { EnvConfigType } from '@/services/environment';
import type { OPDSCatalog } from '@/types/opds';
import { useSettingsStore } from './settingsStore';
import { getReplicaPersistEnv } from '@/services/sync/replicaPersist';
import { publishReplicaDelete, publishReplicaUpsert } from '@/services/sync/replicaPublish';
import {
  computeOpdsCatalogContentId,
  OPDS_CATALOG_KIND,
} from '@/services/sync/adapters/opdsCatalog';

const publishOpdsUpsert = (catalog: OPDSCatalog): void => {
  if (!catalog.contentId) return;
  void publishReplicaUpsert(OPDS_CATALOG_KIND, catalog, catalog.contentId, catalog.reincarnation);
};

const publishOpdsDelete = (contentId: string): void => {
  void publishReplicaDelete(OPDS_CATALOG_KIND, contentId);
};

/**
 * Backfill `contentId` (and `addedAt`) on legacy catalogs that predate
 * replica sync. Returns the same array reference if no changes were
 * required so callers can cheaply detect a no-op.
 *
 * `addedAt` is assigned per array index so the existing display order
 * survives the migration: index 0 (newest in the legacy array) gets
 * the largest timestamp, index N gets the smallest. The total span is
 * tiny (≤ N ms) so newly-imported catalogs (with `Date.now()`) still
 * sort above the migrated set, which matches the legacy "prepend new
 * entries" UX.
 */
const backfillSyncFields = (catalogs: OPDSCatalog[]): OPDSCatalog[] => {
  let mutated = false;
  const baseTime = Date.now();
  const next = catalogs.map((c, i) => {
    if (c.contentId && c.addedAt !== undefined) return c;
    mutated = true;
    return {
      ...c,
      contentId: c.contentId ?? computeOpdsCatalogContentId(c.url),
      addedAt: c.addedAt ?? baseTime - i,
    };
  });
  return mutated ? next : catalogs;
};

interface OPDSStoreState {
  catalogs: OPDSCatalog[];
  loading: boolean;

  /** Visible catalogs sorted by `addedAt` descending (newest first). */
  getAvailableCatalogs(): OPDSCatalog[];
  getCatalog(id: string): OPDSCatalog | undefined;
  /** Look up by URL — used for popular-catalog dedup (independent of contentId). */
  findByUrl(url: string): OPDSCatalog | undefined;
  /** Look up by stable cross-device content id. */
  findByContentId(contentId: string): OPDSCatalog | undefined;

  /**
   * Add (or revive) a catalog. Computes `contentId` from URL if absent.
   * Re-import of a previously soft-deleted entry mints a reincarnation
   * token so the server-side tombstone is replaced with a fresh row.
   */
  addCatalog(catalog: Omit<OPDSCatalog, 'contentId'> & { contentId?: string }): OPDSCatalog;
  /**
   * Patch a catalog's mutable fields. Only the patched fields are
   * republished — credentials (username/password) are NOT in the
   * synced field set yet, so editing them stays local-only until the
   * encrypted-field PR lands.
   */
  updateCatalog(id: string, patch: Partial<OPDSCatalog>): OPDSCatalog | undefined;
  /** Soft-delete by id; pushes a tombstone if the entry has a contentId. */
  removeCatalog(id: string): boolean;

  /**
   * Add a catalog received via replica sync from another device. Same
   * effect on local state as addCatalog, but does NOT republish.
   */
  applyRemoteCatalog(catalog: OPDSCatalog): void;
  /** Mirror a server-side tombstone locally without re-publishing. */
  softDeleteByContentId(contentId: string): void;

  /** Hydrate from `settings.opdsCatalogs`. Backfills sync fields if needed. */
  loadCustomOPDSCatalogs(envConfig: EnvConfigType): Promise<void>;
  /** Persist current state back into settings. */
  saveCustomOPDSCatalogs(envConfig: EnvConfigType): Promise<void>;
}

export const useCustomOPDSStore = create<OPDSStoreState>((set, get) => ({
  catalogs: [],
  loading: false,

  getAvailableCatalogs: () =>
    get()
      .catalogs.filter((c) => !c.deletedAt)
      .sort((a, b) => (b.addedAt || 0) - (a.addedAt || 0)),

  getCatalog: (id) => get().catalogs.find((c) => c.id === id),

  findByUrl: (url) => {
    const normalized = url.trim().toLowerCase();
    return get().catalogs.find((c) => c.url.trim().toLowerCase() === normalized && !c.deletedAt);
  },

  findByContentId: (contentId) =>
    contentId ? get().catalogs.find((c) => c.contentId === contentId) : undefined,

  addCatalog: (input) => {
    const contentId = input.contentId ?? computeOpdsCatalogContentId(input.url);
    // Revive tombstoned entry under a reincarnation token so the
    // server-side tombstone gets replaced rather than stuck.
    const existing = get().catalogs.find((c) => c.contentId === contentId);
    const reincarnation =
      existing?.deletedAt && !input.reincarnation
        ? Math.random().toString(36).slice(2)
        : input.reincarnation;
    const catalog: OPDSCatalog = {
      ...input,
      contentId,
      addedAt: input.addedAt ?? existing?.addedAt ?? Date.now(),
      deletedAt: undefined,
      reincarnation,
    };
    set((state) => {
      const idx = state.catalogs.findIndex((c) => c.contentId === contentId);
      const catalogs =
        idx >= 0
          ? state.catalogs.map((c, i) => (i === idx ? catalog : c))
          : [...state.catalogs, catalog];
      return { catalogs };
    });
    publishOpdsUpsert(catalog);
    return catalog;
  },

  updateCatalog: (id, patch) => {
    let updated: OPDSCatalog | undefined;
    set((state) => {
      const idx = state.catalogs.findIndex((c) => c.id === id);
      if (idx < 0) return state;
      const old = state.catalogs[idx]!;
      if (old.deletedAt) return state;
      updated = { ...old, ...patch };
      // Recompute contentId only if the URL itself changed; otherwise
      // preserve the existing one so we keep the same server row.
      if (patch.url && patch.url !== old.url) {
        updated.contentId = computeOpdsCatalogContentId(patch.url);
      }
      return {
        catalogs: state.catalogs.map((c, i) => (i === idx ? updated! : c)),
      };
    });
    if (updated) publishOpdsUpsert(updated);
    return updated;
  },

  removeCatalog: (id) => {
    const catalog = get().catalogs.find((c) => c.id === id);
    if (!catalog) return false;
    set((state) => ({
      catalogs: state.catalogs.map((c) => (c.id === id ? { ...c, deletedAt: Date.now() } : c)),
    }));
    if (catalog.contentId) publishOpdsDelete(catalog.contentId);
    return true;
  },

  applyRemoteCatalog: (catalog) => {
    set((state) => {
      const idx = state.catalogs.findIndex((c) => c.contentId === catalog.contentId);
      if (idx >= 0) {
        // Preserve local-only fields (username/password — not yet in the
        // synced field set) when overlaying a remote update.
        const old = state.catalogs[idx]!;
        const merged: OPDSCatalog = {
          ...catalog,
          username: old.username,
          password: old.password,
          deletedAt: undefined,
        };
        return { catalogs: state.catalogs.map((c, i) => (i === idx ? merged : c)) };
      }
      return { catalogs: [...state.catalogs, catalog] };
    });
    const env = getReplicaPersistEnv();
    if (env) void get().saveCustomOPDSCatalogs(env);
  },

  softDeleteByContentId: (contentId) => {
    const target = get().catalogs.find((c) => c.contentId === contentId && !c.deletedAt);
    if (!target) return;
    set((state) => ({
      catalogs: state.catalogs.map((c) =>
        c.id === target.id ? { ...c, deletedAt: Date.now() } : c,
      ),
    }));
    const env = getReplicaPersistEnv();
    if (env) void get().saveCustomOPDSCatalogs(env);
  },

  loadCustomOPDSCatalogs: async (_envConfig) => {
    try {
      const { settings } = useSettingsStore.getState();
      const persisted = settings?.opdsCatalogs ?? [];
      const backfilled = backfillSyncFields(persisted);
      set({ catalogs: backfilled });
      // If backfill mutated anything, persist + publish the fresh
      // contentIds so existing catalogs start syncing on next push.
      if (backfilled !== persisted) {
        await get().saveCustomOPDSCatalogs(_envConfig);
        for (const c of backfilled) {
          if (c.contentId && !c.deletedAt) publishOpdsUpsert(c);
        }
      }
    } catch (error) {
      console.error('Failed to load OPDS catalogs:', error);
    }
  },

  saveCustomOPDSCatalogs: async (_envConfig) => {
    try {
      const { settings, setSettings, saveSettings } = useSettingsStore.getState();
      const { catalogs } = get();
      // Tombstoned entries stay in memory so the orchestrator can detect
      // re-import / reincarnation, but they're stripped at the
      // persistence boundary. The next pull will mirror server-side
      // tombstones back into memory if the row is still deleted.
      settings.opdsCatalogs = catalogs.filter((c) => !c.deletedAt);
      setSettings(settings);
      saveSettings(_envConfig, settings);
    } catch (error) {
      console.error('Failed to save OPDS catalogs:', error);
      throw error;
    }
  },
}));

/**
 * Look up an OPDS catalog by its cross-device contentId, falling back to
 * the persisted settings when the in-memory store is empty. The pull-side
 * orchestrator runs before the OPDS page mounts; without the fallback
 * every refresh would treat existing catalogs as new and double up.
 */
export const findOPDSCatalogByContentId = (contentId: string): OPDSCatalog | undefined => {
  if (!contentId) return undefined;
  const inMemory = useCustomOPDSStore.getState().findByContentId(contentId);
  if (inMemory) return inMemory;
  const persisted = useSettingsStore.getState().settings?.opdsCatalogs ?? [];
  return persisted.find((c) => c.contentId === contentId && !c.deletedAt);
};