import type { ToolboxCatalogTheme } from "./types.js";

export const TOOLBOX_PREFERENCES_KEY =
  "@add-ideas/toolbox-portal:v1:preferences" as const;

export type ToolboxThemeMode = ToolboxCatalogTheme["mode"];

export interface ToolboxPreferences {
  version: 1;
  pinned: string[];
  order: string[];
  hidden: string[];
  theme: ToolboxThemeMode;
}

export interface ToolboxPreferenceStorage {
  getItem(key: string): string | null;
  setItem(key: string, value: string): void;
}

export const defaultToolboxPreferences: Readonly<ToolboxPreferences> = {
  version: 1,
  pinned: [],
  order: [],
  hidden: [],
  theme: "system",
};

function freshDefaults(): ToolboxPreferences {
  return {
    ...defaultToolboxPreferences,
    pinned: [],
    order: [],
    hidden: [],
  };
}

function uniqueStrings(value: unknown, field: string): string[] {
  if (
    !Array.isArray(value) ||
    value.some((item) => typeof item !== "string" || item.length === 0)
  ) {
    throw new Error(`${field} must be an array of non-empty strings.`);
  }
  return [...new Set(value)];
}

export function parseToolboxPreferences(value: unknown): ToolboxPreferences {
  if (typeof value !== "object" || value === null || Array.isArray(value)) {
    throw new Error("Preferences must be a JSON object.");
  }

  const candidate = value as Record<string, unknown>;
  if (candidate.version !== 1) {
    throw new Error("Unsupported preferences version.");
  }

  const theme = candidate.theme;
  if (theme !== "light" && theme !== "dark" && theme !== "system") {
    throw new Error("Invalid theme preference.");
  }

  return {
    version: 1,
    pinned: uniqueStrings(candidate.pinned, "pinned"),
    order: uniqueStrings(candidate.order, "order"),
    hidden: uniqueStrings(candidate.hidden, "hidden"),
    theme,
  };
}

export function readToolboxPreferences(
  storage?: ToolboxPreferenceStorage,
): ToolboxPreferences {
  if (!storage) return freshDefaults();
  const value = storage.getItem(TOOLBOX_PREFERENCES_KEY);
  if (!value) return freshDefaults();

  try {
    return parseToolboxPreferences(JSON.parse(value));
  } catch {
    return freshDefaults();
  }
}

export function writeToolboxPreferences(
  preferences: ToolboxPreferences,
  storage: ToolboxPreferenceStorage,
): void {
  storage.setItem(
    TOOLBOX_PREFERENCES_KEY,
    JSON.stringify(parseToolboxPreferences(preferences)),
  );
}