// SerialSGS — Search block.
//
// Wraps the greedy serial Schedule Generation Scheme as a registry-named
// search so a run config can select the backend declaratively. Future
// backends (CP-SAT, MiniZinc subprocess) register beside it under their own
// versioned codes rather than forking the run API.

import { z } from "zod";

import { serialSGS } from "../level-core/search/serialSGS.ts";
import type { Search } from "../level-core/types.ts";

import type { MiniZincFragment, SearchBlock } from "./types.ts";

export const SerialSGSInputSchema = z.object({});

export type SerialSGSInput = z.infer<typeof SerialSGSInputSchema>;

const SearchOutputSchema: z.ZodType<Search> = z.custom<Search>(
  (val): val is Search =>
    typeof val === "object" &&
    val !== null &&
    typeof (val as Search).name === "string" &&
    typeof (val as Search).run === "function",
);

export const SerialSGSBlock: SearchBlock<SerialSGSInput> = {
  id: "SerialSGS",
  schema: { input: SerialSGSInputSchema, output: SearchOutputSchema },
  apply: (): Search => serialSGS,
  toMiniZinc: (): MiniZincFragment => ({
    // The search itself never lowers to MiniZinc — a MiniZinc backend
    // replaces it wholesale. Emitted as a comment so concatenated compiles
    // stay valid.
    text: `% search: greedy serial-SGS (in-process; not a MiniZinc construct)`,
  }),
  doc: {
    nl: "Greedy serial schedule-generation scheme: topological order, earliest feasible placement per task. Deterministic, single schedule per run.",
    pseudocode:
      "for task in topo order: place at earliest day satisfying precedence + caps",
  },
};