import { describe, expect, it } from "@effect/vitest"; import { inferShape, mergeShapes, observeShape, type InferredShape } from "./shape-inference"; describe("inferShape", () => {  it("infers primitives without recording values", () => {    expect(inferShape("secret token")).toEqual({ type: "string" });    expect(inferShape(42)).toEqual({ type: "number" });    expect(inferShape(true)).toEqual({ type: "boolean" });    expect(inferShape(null)).toEqual({ type: "null" });    expect(inferShape(undefined)).toEqual({ type: "null" });  });   it("infers object structure with all keys required", () => {    expect(inferShape({ id: "abc", count: 3 })).toEqual({      type: "object",      properties: { id: { type: "string" }, count: { type: "number" } },      required: ["count", "id"],    });  });   it("merges sampled array elements into one item shape", () => {    expect(inferShape([{ id: 1 }, { id: 2, label: "x" }])).toEqual({      type: "array",      items: {        type: "object",        properties: { id: { type: "number" }, label: { type: "string" } },        required: ["id"],      },    });  });   it("keeps an empty array itemless", () => {    expect(inferShape([])).toEqual({ type: "array" });  });   it("collapses wide objects to a map so data-bearing keys never persist", () => {    const byEmail = Object.fromEntries(      Array.from({ length: 40 }, (_, i) => [`user${i}@example.com`, { active: true }]),    );    const shape = inferShape(byEmail);    expect(shape.properties).toBeUndefined();    expect(shape.additionalProperties).toEqual({      type: "object",      properties: { active: { type: "boolean" } },      required: ["active"],    });  });   it("degrades to unknown past the depth bound", () => {    let value: unknown = "leaf";    for (let i = 0; i < 10; i++) value = { child: value };    const json = JSON.stringify(inferShape(value));    expect(json).toContain("{}");  });}); describe("mergeShapes", () => {  it("makes fields missing from one observation optional", () => {    const merged = mergeShapes(inferShape({ id: "a", email: "x@y.z" }), inferShape({ id: "b" }));    expect(merged).toEqual({      type: "object",      properties: { id: { type: "string" }, email: { type: "string" } },      required: ["id"],    });  });   it("unions differing primitive types", () => {    expect(mergeShapes({ type: "string" }, { type: "number" })).toEqual({      anyOf: [{ type: "string" }, { type: "number" }],    });  });   it("merges same-typed union branches instead of duplicating them", () => {    const union = mergeShapes({ type: "string" }, { type: "null" });    const widened = mergeShapes(union, inferShape({ id: 1 }));    const again = mergeShapes(widened, inferShape({ id: 2, extra: true }));    expect(again.anyOf).toHaveLength(3);    const objectBranch = again.anyOf?.find((branch) => branch.type === "object");    expect(objectBranch?.required).toEqual(["id"]);  });   it("degrades to unknown when the union grows past its cap", () => {    const wide = [      { type: "string" } as const,      { type: "number" } as const,      { type: "boolean" } as const,      { type: "null" } as const,      { type: "array" } as const,    ].reduce<InferredShape>((left, right) => mergeShapes(left, right), { type: "string" });    expect(wide).toEqual({});  });   it("merges array item shapes across calls", () => {    const merged = mergeShapes(inferShape([{ id: 1 }]), inferShape([{ id: 2, done: false }]));    expect(merged).toEqual({      type: "array",      items: {        type: "object",        properties: { id: { type: "number" }, done: { type: "boolean" } },        required: ["id"],      },    });  });}); describe("observeShape", () => {  it("starts a record from the first observation", () => {    const record = observeShape(null, { ok: true }, 1000);    expect(record.observations).toBe(1);    expect(record.updatedAt).toBe(1000);    expect(record.schema.type).toBe("object");  });   it("accumulates observations by merging", () => {    const first = observeShape(null, { id: "a", email: "x@y.z" }, 1000);    const second = observeShape(first, { id: "b" }, 2000);    expect(second.observations).toBe(2);    expect(second.updatedAt).toBe(2000);    expect(second.schema.required).toEqual(["id"]);    expect(Object.keys(second.schema.properties ?? {}).sort()).toEqual(["email", "id"]);  });   it("stays under the serialized size bound for adversarial payloads", () => {    const wide = Object.fromEntries(      Array.from({ length: 24 }, (_, i) => [        `field_with_a_rather_long_name_${i}`,        Object.fromEntries(          Array.from({ length: 24 }, (_, j) => [`nested_property_name_${j}`, { deep: { x: 1 } }]),        ),      ]),    );    const record = observeShape(null, wide, 1000);    expect(JSON.stringify(record.schema).length).toBeLessThanOrEqual(16_000);  });});