import { describe, expect, test } from "bun:test";
import { defineAuthz } from "../src/registry.ts";
import { mergeCatalogs } from "../src/catalog.ts";
import { memoryPermissionStore } from "../src/store.ts";
import { memoryAuditSink } from "../src/audit.ts";
import { createAuthzResolver, expandRoles, permissionMatches } from "../src/engine.ts";

const catalog = mergeCatalogs([
  {
    source: "test.ts",
    module: defineAuthz({
      permissions: {
        "post:read": { public: true },
        "post:write": {},
        "post:delete": { risk: "high" },
        "post:comment:delete": {},
      },
      roles: {
        editor: ["post:*"],
        moderator: ["post:comment:*"],
        admin: ["role:editor", "post:delete"],
        cyclic: ["role:cyclic", "post:read"],
      },
      policies: {
        ownsPost: async (subject: { id?: string }, resource?: { authorId?: string }) =>
          resource?.authorId === subject?.id
            ? { allowed: true }
            : { allowed: false, reason: "not the author", policy: "ownsPost" },
        explodes: async () => {
          throw new Error("policy blew up");
        },
      },
      bindings: { "post:write": ["ownsPost"] },
    }),
  },
]);

const make = (store = memoryPermissionStore(), audit = memoryAuditSink()) => ({
  store,
  audit,
  resolver: createAuthzResolver({ catalog, store, audit, strict: false }),
});

describe("expandRoles", () => {
  test("expands wildcards and role inheritance", () => {
    expect([...expandRoles(catalog, ["admin"])].sort()).toEqual(["post:*", "post:delete"]);
  });
  test("terminates on cyclic inheritance", () => {
    expect([...expandRoles(catalog, ["cyclic"])]).toEqual(["post:read"]);
  });
});

describe("permissionMatches", () => {
  test("matches exact, root wildcard, and every namespace depth", () => {
    expect(permissionMatches(new Set(["post:read"]), "post:read")).toBe(true);
    expect(permissionMatches(new Set(["*"]), "anything:at:all")).toBe(true);
    expect(permissionMatches(new Set(["post:*"]), "post:comment:delete")).toBe(true);
    expect(permissionMatches(new Set(["post:comment:*"]), "post:comment:delete")).toBe(true);
    expect(permissionMatches(new Set(["post:comment:*"]), "post:write")).toBe(false);
  });
});

describe("createAuthzResolver.decide", () => {
  test("allows a public permission for an anonymous subject", async () => {
    const { resolver } = make();
    const result = await resolver.decide({ subject: null, permission: "post:read" });
    expect(result.allowed).toBe(true);
  });

  test("denies a non-public permission for an anonymous subject", async () => {
    const { resolver } = make();
    const result = await resolver.decide({ subject: null, permission: "post:delete" });
    expect(result.allowed).toBe(false);
  });

  test("allows via a role-derived wildcard", async () => {
    const { store, resolver } = make();
    await store.assignRole("u1", "moderator");
    const result = await resolver.decide({
      subject: { id: "u1" },
      permission: "post:comment:delete",
    });
    expect(result.allowed).toBe(true);
  });

  test("an explicit deny beats a role and beats '*'", async () => {
    const { store, resolver } = make();
    await store.assignRole("u1", "admin");
    await store.grant("u1", "post:delete", "deny");
    const result = await resolver.decide({ subject: { id: "u1" }, permission: "post:delete" });
    expect(result.allowed).toBe(false);
    expect(result.reason).toMatch(/explicit deny/i);
  });

  test("a bound policy can deny a permission the role grants", async () => {
    const { store, resolver } = make();
    await store.assignRole("u1", "editor");
    const denied = await resolver.decide({
      subject: { id: "u1" },
      permission: "post:write",
      resource: { authorId: "someone-else" },
    });
    expect(denied.allowed).toBe(false);
    expect(denied.policy).toBe("ownsPost");

    const allowed = await resolver.decide({
      subject: { id: "u1" },
      permission: "post:write",
      resource: { authorId: "u1" },
    });
    expect(allowed.allowed).toBe(true);
  });

  test("a throwing policy denies rather than escaping", async () => {
    const throwing = mergeCatalogs([
      {
        source: "t.ts",
        module: defineAuthz({
          permissions: { "x:go": {} },
          policies: {
            explodes: async () => {
              throw new Error("boom");
            },
          },
          bindings: { "x:go": ["explodes"] },
        }),
      },
    ]);
    const store = memoryPermissionStore();
    await store.grant("u1", "x:go", "allow");
    const resolver = createAuthzResolver({ catalog: throwing, store, strict: false });
    const result = await resolver.decide({ subject: { id: "u1" }, permission: "x:go" });
    expect(result.allowed).toBe(false);
  });

  test("a store failure denies and does not throw", async () => {
    const broken = {
      ...memoryPermissionStore(),
      assignmentsFor: async () => {
        throw new Error("db down");
      },
    };
    const resolver = createAuthzResolver({ catalog, store: broken, strict: false });
    const result = await resolver.decide({ subject: { id: "u1" }, permission: "post:read" });
    expect(result.allowed).toBe(false);
  });

  test("an unregistered permission denies when strict is off", async () => {
    const { resolver } = make();
    const result = await resolver.decide({ subject: { id: "u1" }, permission: "ghost:perm" });
    expect(result.allowed).toBe(false);
    expect(result.reason).toMatch(/not registered/i);
  });

  test("an unregistered permission throws when strict is on", async () => {
    const resolver = createAuthzResolver({
      catalog,
      store: memoryPermissionStore(),
      strict: true,
    });
    await expect(
      resolver.decide({ subject: { id: "u1" }, permission: "ghost:perm" }),
    ).rejects.toThrow(/ghost:perm/);
  });

  test("denials are audited and allows are not, by default", async () => {
    const { store, audit, resolver } = make();
    await store.assignRole("u1", "moderator");
    await resolver.decide({ subject: { id: "u1" }, permission: "post:delete" });
    await resolver.decide({ subject: { id: "u1" }, permission: "post:read" });
    expect(audit.events).toHaveLength(1);
    expect(audit.events[0]!.allowed).toBe(false);
  });

  test("auditAllows records both verdicts", async () => {
    const store = memoryPermissionStore();
    const audit = memoryAuditSink();
    const resolver = createAuthzResolver({
      catalog,
      store,
      audit,
      strict: false,
      auditAllows: true,
    });
    await resolver.decide({ subject: null, permission: "post:read" });
    expect(audit.events).toHaveLength(1);
    expect(audit.events[0]!.allowed).toBe(true);
  });

  test("tenant scope selects the right assignments", async () => {
    const { store, resolver } = make();
    await store.assignRole("u1", "editor", { tenantId: "t1" });
    const inside = await resolver.decide({
      subject: { id: "u1" },
      permission: "post:write",
      resource: { authorId: "u1" },
      scope: { tenantId: "t1" },
    });
    const outside = await resolver.decide({
      subject: { id: "u1" },
      permission: "post:write",
      resource: { authorId: "u1" },
      scope: { tenantId: "t2" },
    });
    expect(inside.allowed).toBe(true);
    expect(outside.allowed).toBe(false);
  });
});