import type { Anchor, DockMode, Position, Size } from "./types";

export type PersistedContextState = {
  anchor?: Anchor;
  anchorOffset?: Position;
  size?: Size;
  hasCustomPosition?: boolean;
};

export type PersistedState = {
  button?: Omit<PersistedContextState, "size">;
  window?: PersistedContextState;
  isOpen?: boolean;
  dockMode?: DockMode;
  selectedMenu?: string;
  selectedContext?: string;
};

export function loadInspectorState(storageKey: string): PersistedState | null {
  if (typeof window === "undefined") {
    return null;
  }

  const raw = window.localStorage.getItem(storageKey);
  if (raw) {
    try {
      const parsed = JSON.parse(raw);
      if (parsed && typeof parsed === "object") {
        return parsed as PersistedState;
      }
    } catch {
      // Fall through to cookie migration path
    }
  }

  // Backwards compatibility: try to read the legacy cookie and migrate it
  if (typeof document !== "undefined") {
    const prefix = `${storageKey}=`;
    const entry = document.cookie
      .split("; ")
      .find((cookie) => cookie.startsWith(prefix));
    if (entry) {
      const legacyRaw = entry.substring(prefix.length);
      try {
        const parsed = JSON.parse(decodeURIComponent(legacyRaw));
        if (parsed && typeof parsed === "object") {
          return parsed as PersistedState;
        }
      } catch {
        return null;
      }
    }
  }

  return null;
}

export function saveInspectorState(
  storageKey: string,
  state: PersistedState,
): void {
  if (typeof window === "undefined") {
    return;
  }

  try {
    window.localStorage.setItem(storageKey, JSON.stringify(state));
  } catch (error) {
    console.warn("Failed to persist inspector state", error);
  }
}

export function isValidAnchor(value: unknown): value is Anchor {
  if (!value || typeof value !== "object") {
    return false;
  }

  const candidate = value as Anchor;
  return (
    (candidate.horizontal === "left" || candidate.horizontal === "right") &&
    (candidate.vertical === "top" || candidate.vertical === "bottom")
  );
}

export function isValidPosition(value: unknown): value is Position {
  if (!value || typeof value !== "object") {
    return false;
  }

  const candidate = value as Position;
  return isFiniteNumber(candidate.x) && isFiniteNumber(candidate.y);
}

export function isValidSize(value: unknown): value is Size {
  if (!value || typeof value !== "object") {
    return false;
  }

  const candidate = value as Size;
  return isFiniteNumber(candidate.width) && isFiniteNumber(candidate.height);
}

export function isFiniteNumber(value: unknown): value is number {
  return typeof value === "number" && Number.isFinite(value);
}

export function isValidDockMode(value: unknown): value is DockMode {
  return value === "floating" || value === "docked-left";
}