import { useCallback, useEffect, useMemo, useState, type ReactNode } from "react";
import { coercePlexFilters, EMPTY_PLEX_FILTERS, type PlexFilters } from "../lib/api";
import { parseSortState, type SortState } from "../lib/columnSort";
import { parsePlexField, type PlexSearchField } from "../lib/plexSearch";
import { PLEX_SORT_FALLBACK } from "../lib/plexSort";
import {
  hasPlexParams,
  plexParamsToState,
  plexParamUpdates,
  type PlexUrlState,
} from "../lib/plexUrlState";
import { getAccountRaw, LS, setAccountRaw } from "../lib/storage";
import { logFilterChange } from "../lib/filterLog";
import { useUrlMirror } from "../lib/useUrlMirror";
import { useNavigation } from "./navigationContext";
import {
  PlexActionsContext,
  PlexStateContext,
  type PlexActions,
  type PlexJumpTarget,
  type PlexState,
} from "./plexContext";

// Owns the Plex module's shared local state — the left-rail library scope / watch-state / sort /
// expanded filters, the header search term, and the "open this playlist" hand-off — lifted out of
// App so the PlexSidebar (rail), PlexBrowse (content), and the header search box read it via hooks
// instead of prop-drilling through App. Mirrors FeedFiltersProvider (split State + Actions contexts,
// stable useCallback setters, one-line hooks; composed in main.tsx around <App/>).
//
// scope / show / sort / filters / q are per-account persisted (localStorage) and seeded from it at mount
// (BootGate claims the local state for the account first; a different account reloads the tab). `playlistOpen` is an ephemeral
// hand-off (the rail sets it, PlexBrowse consumes it into a history subview then clears it). The Plex
// search term is deliberately its OWN state, NOT the feed's `filters.q`, so a Plex search never leaks
// into (and is never greeted by a stale value from) the feed.
//
// The contexts, their value types and the hooks live in plexContext.ts.

// The per-account init readers, shared by the useState seeds and the shared-link seed's base.
function readPlexScope(): string {
  const v = getAccountRaw(LS.plexLibrary) ?? "both";
  return ["movie", "show", "both"].includes(v) ? v : "both";
}
const readPlexShow = (): string => getAccountRaw(LS.plexShow) ?? "all";
const readPlexFiltersRaw = (): string => getAccountRaw(LS.plexFilters) ?? "{}";
const readPlexQ = (): string => getAccountRaw(LS.plexQ) ?? "";
const readPlexField = (): PlexSearchField => parsePlexField(getAccountRaw(LS.plexField));
// Sort is a {key,dir} SortState. Migrate the old shape: a legacy bare-key string in plexSort plus the
// direction that used to live in plexFilters.sortDir — so an existing sort preference survives the
// upgrade rather than snapping back to the default.
function readPlexSort(): SortState {
  const raw = getAccountRaw(LS.plexSort);
  if (!raw) return PLEX_SORT_FALLBACK;
  let wasJson = false;
  try {
    const parsed = parseSortState(JSON.parse(raw));
    wasJson = true;
    if (parsed) return parsed;
  } catch {
    /* not JSON → a legacy bare-key string, handled below */
  }
  // Valid JSON that wasn't a SortState is corrupt — fall back rather than treat the JSON text as a
  // key. Only a non-JSON raw is a genuine legacy bare key.
  if (wasJson) return PLEX_SORT_FALLBACK;
  let dir: "asc" | "desc" = "asc";
  try {
    if (
      (JSON.parse(getAccountRaw(LS.plexFilters) ?? "{}") as { sortDir?: string }).sortDir === "desc"
    )
      dir = "desc";
  } catch {
    /* ignore */
  }
  return { key: raw, dir };
}

// A shared Plex-browse link carries the content state in namespaced URL keys (pscope/psort/pshow/
// pf). When present, the URL wins over this account's stored view (like the feed's URL-over-localStorage
// seed) — read once at mount. The keys are Plex-unique, so their mere presence identifies a shared Plex
// view; no ?page check is needed (and the mirror below is page-gated so it never pollutes other pages).
function readPlexFilters(): PlexFilters {
  try {
    return coercePlexFilters(JSON.parse(readPlexFiltersRaw()) as Record<string, unknown>);
  } catch {
    return EMPTY_PLEX_FILTERS;
  }
}
// The base is this account's stored view (BootGate claims the local state before this provider mounts), so a
// PARTIAL link — one carrying only the scope, say — keeps the stored sort, show and filters for the rest.
// `present` records which dimensions the link actually carried: only those are persisted (below).
type PlexSeedPresent = { scope: boolean; sort: boolean; show: boolean; filters: boolean };
type PlexUrlSeed = PlexUrlState & { present: PlexSeedPresent };
function readPlexUrlSeed(): PlexUrlSeed | null {
  const params = new URLSearchParams(window.location.search);
  if (!hasPlexParams(params)) return null;
  const state = plexParamsToState(params, {
    scope: readPlexScope(),
    sort: readPlexSort(),
    show: readPlexShow(),
    filters: readPlexFilters(),
  });
  const present = {
    scope: params.has("pscope"),
    sort: params.has("psort"),
    show: params.has("pshow"),
    filters: params.has("pf"),
  };
  return { ...state, present };
}

export function PlexProvider({ children }: { children: ReactNode }) {
  // Captured once: the shared-link content state (or null). Seeds the slices below and is persisted to
  // the account (the effect further down), so the shared view also survives a later plain reload.
  const [urlSeed] = useState(readPlexUrlSeed);
  // The former per-library picker is now a cross-library SCOPE: movie | show | both (unified library).
  // (Reuses the old LS.plexLibrary key; an old stored library-id value falls back to "both".)
  const [scope, setScopeState] = useState<string>(() => urlSeed?.scope ?? readPlexScope());
  const [show, setShowState] = useState<string>(() => urlSeed?.show ?? readPlexShow());
  const [sort, setSortState] = useState<SortState>(() => urlSeed?.sort ?? readPlexSort());
  // The expanded Plex filters live as one JSON blob (the string-only account store serializes it).
  const [filtersRaw, setFiltersRaw] = useState<string>(() =>
    urlSeed ? JSON.stringify(urlSeed.filters) : readPlexFiltersRaw(),
  );
  const filters = useMemo<PlexFilters>(() => {
    try {
      // coercePlexFilters fills defaults, drops the legacy `sortDir` (direction now lives in the sort
      // SortState — left here it would leak into the facets key and be re-persisted), and migrates the
      // legacy single `collection`/`collectionTitle` into `collections`/`collectionTitles`. Shared with
      // the saved-views provider so the localStorage seed and a DB view blob coerce identically.
      return coercePlexFilters(JSON.parse(filtersRaw));
    } catch {
      return EMPTY_PLEX_FILTERS;
    }
  }, [filtersRaw]);
  // Survives F5 (persisted), unlike the feed search — see the scope note above.
  const [q, setQState] = useState<string>(readPlexQ);
  const [field, setFieldState] = useState<PlexSearchField>(readPlexField);
  const [playlistOpen, setPlaylistOpen] = useState<number | null>(null);
  // Ephemeral hand-off like `playlistOpen`: the header typeahead sets the title to jump to;
  // PlexBrowse consumes it into an info/show history subview then clears it.
  const [jumpTo, setJumpTo] = useState<PlexJumpTarget | null>(null);

  // Persist a shared link's view to the account once, so it wins over the stored view and survives a
  // later plain reload. Mirrors FeedFiltersProvider's initialHadUrlFilters branch. Only the dimensions
  // the link CARRIED are written: an omitted one already reads from storage, and writing its default
  // would not be a no-op — a stored Plex filters value at all is what tells SavedViewsProvider the
  // account has picked filters, so the account's default saved view would never be applied again.
  useEffect(() => {
    if (!urlSeed) return;
    const { present } = urlSeed;
    if (present.scope) setAccountRaw(LS.plexLibrary, urlSeed.scope);
    if (present.show) setAccountRaw(LS.plexShow, urlSeed.show);
    if (present.sort) setAccountRaw(LS.plexSort, JSON.stringify(urlSeed.sort));
    if (present.filters) setAccountRaw(LS.plexFilters, JSON.stringify(urlSeed.filters));
  }, [urlSeed]);

  const setScope = useCallback((v: string) => {
    logFilterChange("plex", { scope: v });
    setScopeState(v);
    setAccountRaw(LS.plexLibrary, v);
  }, []);
  const setShow = useCallback((v: string) => {
    logFilterChange("plex", { show: v });
    setShowState(v);
    setAccountRaw(LS.plexShow, v);
  }, []);
  const setSort = useCallback((v: SortState) => {
    logFilterChange("plex", { sort: v });
    setSortState(v);
    setAccountRaw(LS.plexSort, JSON.stringify(v));
  }, []);
  const setFilters = useCallback((f: PlexFilters) => {
    logFilterChange("plex", { filters: f });
    const s = JSON.stringify(f);
    setFiltersRaw(s);
    setAccountRaw(LS.plexFilters, s);
  }, []);
  const setQ = useCallback((v: string) => {
    logFilterChange("plex", {}, v);
    setQState(v);
    setAccountRaw(LS.plexQ, v);
  }, []);
  const setField = useCallback((v: PlexSearchField) => {
    logFilterChange("plex", { field: v });
    setFieldState(v);
    setAccountRaw(LS.plexField, v);
  }, []);

  const state = useMemo<PlexState>(
    () => ({ scope, show, sort, filters, q, field, playlistOpen, jumpTo }),
    [scope, show, sort, filters, q, field, playlistOpen, jumpTo],
  );
  const actions = useMemo<PlexActions>(
    () => ({ setScope, setShow, setSort, setFilters, setQ, setField, setPlaylistOpen, setJumpTo }),
    [setScope, setShow, setSort, setFilters, setQ, setField],
  );

  // Mirror the content state (scope + sort + watch-state + filters) into the address bar under the
  // namespaced keys so a Plex-browse view is shareable. Gated on page===plex: off the Plex page the keys
  // are cleared (localStorage still holds the state; it re-mirrors on return). `q`/`field` stay OUT — the
  // search term is deliberately transient-per-view and not part of the shared four-key contract.
  const { page } = useNavigation();
  useUrlMirror(plexParamUpdates(page === "plex" ? { scope, sort, show, filters } : null));

  return (
    <PlexActionsContext.Provider value={actions}>
      <PlexStateContext.Provider value={state}>{children}</PlexStateContext.Provider>
    </PlexActionsContext.Provider>
  );
}