/**
 * P063 DoD: "a breaking schema is detected BEFORE consumer corruption."
 *
 * Two levels, both tested here:
 *   - the pure comparison (checkCompatibility) per policy direction, and
 *   - the registry refusing to record a version that breaks the PREVIOUS
 *     version's declared policy — including the bypass where a producer tries
 *     to widen its own policy to "none" on the breaking version.
 *
 * The end-to-end "no consumer write happened" proof lives in
 * tests/p0/ingestion-runner.test.ts, which asserts the sink was never called.
 */
import { describe, expect, it } from "vitest";
import { checkCompatibility, conformanceErrors } from "@/src/schema/compatibility";
import { SchemaRegistry } from "@/src/schema/schema-registry";
import { InMemoryIngestionRepository } from "@/src/repositories/in-memory-ingestion-repository";
import { SiaxError } from "@/src/platform/errors";
import type { RecordSchemaFields } from "@/src/schema/record-schema";

const V1: RecordSchemaFields = {
  org_number: { type: "string", required: true },
  name: { type: "string", required: true },
  employees: { type: "number", required: false },
};

describe("P063 compatibility rules", () => {
  it("adding an OPTIONAL field is backward-compatible", () => {
    const next = { ...V1, sni_code: { type: "string" as const, required: false } };
    expect(checkCompatibility(V1, next, "backward").compatible).toBe(true);
  });

  it("adding a REQUIRED field breaks backward compatibility", () => {
    const next = { ...V1, sni_code: { type: "string" as const, required: true } };
    const verdict = checkCompatibility(V1, next, "backward");
    expect(verdict.compatible).toBe(false);
    expect(verdict.breaks[0].field).toBe("sni_code");
    expect(verdict.breaks[0].detail).toContain("absent from every record written under the previous version");
  });

  it("adding a required field is FORWARD-safe — direction matters", () => {
    const next = { ...V1, sni_code: { type: "string" as const, required: true } };
    expect(checkCompatibility(V1, next, "forward").compatible).toBe(true);
    expect(checkCompatibility(V1, next, "full").compatible).toBe(false);
  });

  it("removing a required field breaks BOTH directions", () => {
    const next: RecordSchemaFields = { org_number: V1.org_number, employees: V1.employees };
    expect(checkCompatibility(V1, next, "backward").compatible).toBe(false);
    expect(checkCompatibility(V1, next, "forward").compatible).toBe(false);
  });

  it("removing an OPTIONAL field is backward-safe but not forward-safe", () => {
    const next: RecordSchemaFields = { org_number: V1.org_number, name: V1.name };
    expect(checkCompatibility(V1, next, "backward").compatible).toBe(true);
    expect(checkCompatibility(V1, next, "forward").compatible).toBe(true);
  });

  it("a type change breaks every policy except an explicit 'none'", () => {
    const next: RecordSchemaFields = { ...V1, employees: { type: "string", required: false } };
    expect(checkCompatibility(V1, next, "backward").compatible).toBe(false);
    expect(checkCompatibility(V1, next, "forward").compatible).toBe(false);
    expect(checkCompatibility(V1, next, "full").compatible).toBe(false);
    expect(checkCompatibility(V1, next, "none").compatible).toBe(true);
  });

  it("conformanceErrors catches a record that silently stopped matching its schema", () => {
    expect(conformanceErrors(V1, { org_number: "556001-0001", name: "Alfa AB" })).toEqual([]);
    expect(conformanceErrors(V1, { org_number: "556001-0001" })).toContain('required field "name" is missing');
    expect(conformanceErrors(V1, { org_number: "556001-0001", name: "Alfa", employees: "ten" })).toContain(
      'field "employees" is string, expected number',
    );
    expect(conformanceErrors(V1, { org_number: "1", name: "A", surprise: true })).toContain(
      'unregistered field "surprise" appeared in the payload',
    );
  });
});

describe("P063 schema registry — versioning and refusal", () => {
  function registry() {
    return new SchemaRegistry(new InMemoryIngestionRepository());
  }

  it("the first registration is v1; an identical re-registration does not create v2", async () => {
    const reg = registry();
    const first = await reg.register({ source_id: "src_a", tenant_id: "t", fields: V1, compatibility: "backward" });
    expect(first.schema.schema_version).toBe(1);
    const again = await reg.register({ source_id: "src_a", tenant_id: "t", fields: V1, compatibility: "backward" });
    expect(again.unchanged).toBe(true);
    expect((await reg.list("src_a")).length).toBe(1);
  });

  it("a compatible change becomes v2", async () => {
    const reg = registry();
    await reg.register({ source_id: "src_b", tenant_id: "t", fields: V1, compatibility: "backward" });
    const v2 = await reg.register({
      source_id: "src_b",
      tenant_id: "t",
      fields: { ...V1, sni_code: { type: "string", required: false } },
      compatibility: "backward",
    });
    expect(v2.schema.schema_version).toBe(2);
    expect((await reg.getLatest("src_b"))?.schema_version).toBe(2);
  });

  it("a BREAKING change is refused and nothing is persisted", async () => {
    const reg = registry();
    await reg.register({ source_id: "src_c", tenant_id: "t", fields: V1, compatibility: "backward" });
    const err = await reg
      .register({
        source_id: "src_c",
        tenant_id: "t",
        fields: { ...V1, sni_code: { type: "string", required: true } },
        compatibility: "backward",
      })
      .catch((e: unknown) => e);
    expect(err).toBeInstanceOf(SiaxError);
    expect((err as SiaxError).code).toBe("CONFLICT");
    expect((err as SiaxError).message).toContain("breaks the declared");
    // Still only v1 on record — a refused registration writes nothing.
    expect((await reg.list("src_c")).map((s) => s.schema_version)).toEqual([1]);
  });

  it("a producer cannot widen its OWN policy to 'none' on the breaking version", async () => {
    const reg = registry();
    await reg.register({ source_id: "src_d", tenant_id: "t", fields: V1, compatibility: "full" });
    // The PREVIOUS version's policy governs — declaring "none" here must not help.
    await expect(
      reg.register({
        source_id: "src_d",
        tenant_id: "t",
        fields: { ...V1, employees: { type: "string", required: false } },
        compatibility: "none",
      }),
    ).rejects.toThrow(/breaks the declared "full" compatibility policy/);
  });

  it("a source that explicitly declared 'none' opts out — recorded, never assumed", async () => {
    const reg = registry();
    await reg.register({ source_id: "src_e", tenant_id: "t", fields: V1, compatibility: "none" });
    const v2 = await reg.register({
      source_id: "src_e",
      tenant_id: "t",
      fields: { ...V1, employees: { type: "string", required: false } },
      compatibility: "none",
    });
    expect(v2.schema.schema_version).toBe(2);
    expect(v2.schema.compatibility).toBe("none");
  });
});