// Deadline — Constraint block.
//
// The task must finish on or before `latestFinish` (a day index in the
// resolved calendar frame). Hard form: a placement that would overrun the
// deadline is rejected and the run fails with an attributed explanation.
//
// MiniZinc compile contract: harness supplies `finish_day[t]`.

import { z } from "zod";

import type { DeadlineConstraint } from "../level-core/types.ts";

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

export const DeadlineInputSchema = z.object({
  taskUniqueId: z.number().int(),
  latestFinish: z.number().int().nonnegative(),
});

export type DeadlineInput = z.infer<typeof DeadlineInputSchema>;

const DeadlineOutputSchema: z.ZodType<DeadlineConstraint> = z.object({
  kind: z.literal("Deadline"),
  taskUniqueId: z.number().int(),
  latestFinish: z.number().int().nonnegative(),
});

export const DeadlineBlock: ConstraintBlock<DeadlineInput> = {
  id: "Deadline",
  schema: { input: DeadlineInputSchema, output: DeadlineOutputSchema },
  apply: ({ taskUniqueId, latestFinish }): DeadlineConstraint => ({
    kind: "Deadline",
    taskUniqueId,
    latestFinish,
  }),
  toMiniZinc: ({ taskUniqueId, latestFinish }): MiniZincFragment => ({
    text: `constraint finish_day[${String(taskUniqueId)}] <= ${String(latestFinish)};`,
  }),
  doc: {
    nl: "The task must finish on or before the given day index; later placements are rejected.",
    pseudocode: "finish(task) <= latestFinish",
  },
};