import { z } from "zod";
import { get_empty_datum_for, Presentation } from "./presentation.svelte.ts";

type Assert<_T extends true> = void;

export const all_datum_tags = [
  "Text",
  "Timestamp",
  "Uuid",
] as const;

// Type checking to ensure that all valid enum tags are included.
type _ = Assert<
  Datum["t"] extends (typeof all_datum_tags)[number] ? true : false
>;

const datum_text_schema = z.object({
  t: z.literal("Text"),
  c: z.string().nullish().transform((x) => x ?? undefined),
});

const datum_timestamp_schema = z.object({
  t: z.literal("Timestamp"),
  c: z.coerce.date().nullish().transform((x) => x ?? undefined),
});

const datum_uuid_schema = z.object({
  t: z.literal("Uuid"),
  c: z.string().nullish().transform((x) => x ?? undefined),
});

export const datum_schema = z.union([
  datum_text_schema,
  datum_timestamp_schema,
  datum_uuid_schema,
]);

export type Datum = z.infer<typeof datum_schema>;

export function parse_clipboard_value(
  presentation: Presentation,
  input: string,
): Datum {
  if (presentation.t === "Dropdown") {
    if (
      presentation.c.allow_custom ||
      presentation.c.options.some(({ value }) => value === input)
    ) {
      return { t: "Text", c: input };
    } else {
      return get_empty_datum_for(presentation);
    }
  } else if (presentation.t === "Text") {
    return { t: "Text", c: input };
  } else if (presentation.t === "Timestamp") {
    // TODO: implement
    console.warn("parsing timestamps from clipboard is not yet supported");
    return get_empty_datum_for(presentation);
  } else if (presentation.t === "Uuid") {
    // TODO: implement
    console.warn("parsing uuids from clipboard is not yet supported");
    return get_empty_datum_for(presentation);
  }
  type _ = Assert<typeof presentation["t"] extends never ? true : false>;
  throw new Error("should be unreachable");
}