/*
<MODULE_CONTRACT>
<purpose>
Unit tests for canonical uri covering RFC-1075 AC-4: deriveCanonicalUri is pure and deterministic.
</purpose>
<non-goals>
  <item>Not a contract source of truth — the module under test owns the authoritative behavior; fixtures are minimal scaffolding only.</item>
</non-goals>
</MODULE_CONTRACT>
<CHANGE_SUMMARY>
  <item>RFC-1311: Compass header sweep — declares the canonical suite's contract for test-file scaffold coverage.</item>
</CHANGE_SUMMARY>
*/

import { describe, it, expect } from "vitest";
import { deriveCanonicalUri } from "../canonical-uri.ts";

describe("RFC-1075 AC-4: deriveCanonicalUri is pure and deterministic", () => {
  it("returns undefined for undefined siteOrigin", () => {
    expect(deriveCanonicalUri(undefined, "business")).toBeUndefined();
    expect(deriveCanonicalUri(undefined, "offering", "off-1")).toBeUndefined();
  });

  it("returns undefined for empty siteOrigin", () => {
    expect(deriveCanonicalUri("", "business")).toBeUndefined();
    expect(deriveCanonicalUri("", "offering", "off-1")).toBeUndefined();
  });

  it("derives business URI without entityId — RFC-1115 .json form", () => {
    expect(deriveCanonicalUri("https://example.example", "business")).toBe(
      "https://example.example/.well-known/entity/business.json",
    );
  });

  it("derives offering URI with entityId — RFC-1115 .json form", () => {
    expect(deriveCanonicalUri("https://example.example", "offering", "off-1")).toBe(
      "https://example.example/.well-known/entity/offering/off-1.json",
    );
  });

  it("slugifies URI-form entityId to its last path segment", () => {
    // PBP entity IDs are URIs; the canonical entity URI must embed a slug,
    // not the raw URI (which would produce a double-scheme, non-FS-safe path).
    expect(
      deriveCanonicalUri(
        "https://example.example",
        "offering",
        "https://example.example/id/offerings/automation",
      ),
    ).toBe("https://example.example/.well-known/entity/offering/automation.json");
  });

  it("returns undefined for offering without entityId", () => {
    expect(deriveCanonicalUri("https://example.example", "offering")).toBeUndefined();
    expect(deriveCanonicalUri("https://example.example", "offering", "")).toBeUndefined();
  });

  it("strips trailing slashes from siteOrigin", () => {
    expect(deriveCanonicalUri("https://example.example/", "business")).toBe(
      "https://example.example/.well-known/entity/business.json",
    );
    expect(deriveCanonicalUri("https://example.example//", "business")).toBe(
      "https://example.example/.well-known/entity/business.json",
    );
  });

  it("is deterministic — same inputs always produce same output", () => {
    const inputs = ["https://example.example", "https://example.example/"] as const;
    for (const origin of inputs) {
      const a = deriveCanonicalUri(origin, "offering", "off-1");
      const b = deriveCanonicalUri(origin, "offering", "off-1");
      expect(a).toBe(b);
    }
  });

  it("is side-effect-free — does not mutate inputs", () => {
    const origin = "https://example.example";
    const before = origin;
    deriveCanonicalUri(origin, "business");
    expect(origin).toBe(before);
  });
});