import { createContext, useCallback, useContext, 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 { useAccountRehydrate } from "../lib/useAccountRehydrate";
import { useUrlMirror } from "../lib/useUrlMirror";
import { useNavigation } from "./NavigationProvider";

// 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). init-from-storage seeds
// them, and useAccountRehydrate re-reads once the tab's account is pinned — this provider mounts above
// <App>, which pins it only after /api/me, so a fresh tab would otherwise show defaults until a reload
// (an account SWITCH does full-reload, but the FIRST load does not). `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.

// A "jump straight to this title" hand-off from the header typeahead: PlexBrowse opens a movie's
// info page (like the card's ⓘ) or a show's drill-down (like clicking a show card) by type.
export type PlexJumpTarget = { id: string; type: "movie" | "show" };

type PlexState = {
  scope: string; // movie | show | both (unified cross-library scope)
  show: string;
  sort: SortState; // {key,dir}; healed against the scope's options at the point of use
  filters: PlexFilters;
  q: string;
  field: PlexSearchField; // search scope-pill; healed against `scope` at the point of use
  playlistOpen: number | null;
  jumpTo: PlexJumpTarget | null; // typeahead → grid hand-off ("open this title")
};

interface PlexActions {
  setScope: (v: string) => void;
  setShow: (v: string) => void;
  setSort: (v: SortState) => void;
  setFilters: (f: PlexFilters) => void;
  setQ: (q: string) => void;
  setField: (f: PlexSearchField) => void;
  setPlaylistOpen: (id: number | null) => void;
  setJumpTo: (t: PlexJumpTarget | null) => void;
}

const StateContext = createContext<PlexState>({
  scope: "both",
  show: "all",
  sort: PLEX_SORT_FALLBACK,
  filters: EMPTY_PLEX_FILTERS,
  q: "",
  field: "all",
  playlistOpen: null,
  jumpTo: null,
});
const ActionsContext = createContext<PlexActions>({
  setScope: () => {},
  setShow: () => {},
  setSort: () => {},
  setFilters: () => {},
  setQ: () => {},
  setField: () => {},
  setPlaylistOpen: () => {},
  setJumpTo: () => {},
});

export function usePlex(): PlexState {
  return useContext(StateContext);
}
export function usePlexActions(): PlexActions {
  return useContext(ActionsContext);
}

// The per-account init readers, shared by the initial useState seed AND the account-pin re-hydrate.
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 };
}

// S4: 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;
  }
}
// A shared-link seed = the URL-merged state PLUS which dimensions the URL actually carried. `present`
// matters because the base below is read at MOUNT, before the account is pinned (getAccountRaw returns
// null then), so the base for an OMITTED dimension is a hard default, NOT this account's stored value.
// The provider must therefore persist/keep only the PRESENT dimensions on account-pin and re-read the
// account's real stored value for the absent ones — otherwise a partial link silently resets them.
type PlexSeedPresent = { scope: boolean; sort: boolean; show: boolean; filters: boolean };
type PlexUrlSeed = { state: 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(),
  });
  return {
    state,
    present: {
      scope: params.has("pscope"),
      sort: params.has("psort"),
      show: params.has("pshow"),
      filters: params.has("pf"),
    },
  };
}

export function PlexProvider({ children }: { children: ReactNode }) {
  // Captured once: the shared-link content state (or null). Seeds the slices below and, on account pin,
  // is persisted to the account instead of being clobbered by the stored view (see the rehydrate).
  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?.state.scope ?? readPlexScope());
  const [show, setShowState] = useState<string>(() => urlSeed?.state.show ?? readPlexShow());
  const [sort, setSortState] = useState<SortState>(() => urlSeed?.state.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.state.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);

  // Re-read every per-account slice once the account is pinned after mount (first load on a fresh tab).
  // A shared-link seed is the exception: instead of reloading the account's stored view, PERSIST the URL
  // state to this account (so the shared view wins and survives a later plain reload), and adopt only the
  // non-shared slices (q/field) from storage. Mirrors FeedFiltersProvider's initialHadUrlFilters branch.
  const markDirty = useAccountRehydrate(() => {
    if (urlSeed) {
      // Per dimension: a dimension the URL carried (present) is the shared view — adopt it and persist
      // it to this now-pinned account (so it wins and survives a later plain reload). A dimension the
      // URL OMITTED was seeded from a mount-time default (no account yet), so do NOT persist that
      // default over the account's real stored value — re-read the stored value instead, exactly like a
      // normal load. This is the fix for a partial shared link silently resetting the omitted slices.
      const { state, present } = urlSeed;
      if (present.scope) setAccountRaw(LS.plexLibrary, state.scope);
      else setScopeState(readPlexScope());
      if (present.show) setAccountRaw(LS.plexShow, state.show);
      else setShowState(readPlexShow());
      if (present.sort) setAccountRaw(LS.plexSort, JSON.stringify(state.sort));
      else setSortState(readPlexSort());
      if (present.filters) setAccountRaw(LS.plexFilters, JSON.stringify(state.filters));
      else setFiltersRaw(readPlexFiltersRaw());
      setQState(readPlexQ());
      setFieldState(readPlexField());
      return;
    }
    setScopeState(readPlexScope());
    setShowState(readPlexShow());
    setSortState(readPlexSort());
    setFiltersRaw(readPlexFiltersRaw());
    setQState(readPlexQ());
    setFieldState(readPlexField());
  });

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

  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],
  );

  // S4: 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 (
    <ActionsContext.Provider value={actions}>
      <StateContext.Provider value={state}>{children}</StateContext.Provider>
    </ActionsContext.Provider>
  );
}