/**
 * Task #242 (B1) — lifecycle transition tests.
 *
 * Unit-half: pure isLegalTransition matrix.
 * DB-half: transitionTo persists row when DATABASE_URL is set.
 */
import { test } from "node:test";
import assert from "node:assert/strict";
import {
  isLegalTransition,
  assertLegalTransition,
  IllegalLifecycleTransitionError,
  ALL_LIFECYCLE_STATES,
  type CapabilityLifecycleState,
} from "../lifecycle.ts";

const LEGAL: ReadonlyArray<[CapabilityLifecycleState, CapabilityLifecycleState]> = [
  ["created", "cold_start"],
  ["cold_start", "graduated"],
  ["cold_start", "degraded"],
  ["graduated", "live"],
  ["graduated", "degraded"],
  ["live", "degraded"],
  ["degraded", "cold_start"],
  ["degraded", "live"],
];

test("lifecycle: isLegalTransition matches expected matrix", () => {
  for (const [from, to] of LEGAL) {
    assert.equal(isLegalTransition(from, to), true, `${from}→${to} should be legal`);
  }
  // self-transition is not legal
  for (const s of ALL_LIFECYCLE_STATES) {
    assert.equal(isLegalTransition(s, s), false, `self ${s}→${s} should not be legal`);
  }
  // a known illegal jump
  assert.equal(isLegalTransition("created", "live"), false);
  assert.equal(isLegalTransition("created", "degraded"), false);
  assert.equal(isLegalTransition("graduated", "cold_start"), false);
  assert.equal(isLegalTransition("live", "created"), false);
});

test("lifecycle: assertLegalTransition throws IllegalLifecycleTransitionError on bad jump", () => {
  assert.throws(
    () => assertLegalTransition("created", "live"),
    (err: unknown) => err instanceof IllegalLifecycleTransitionError,
  );
});

const SKIP_DB = !process.env["DATABASE_URL"];

test(
  "lifecycle: transitionTo persists capability_lifecycle_events row",
  { skip: SKIP_DB && "DATABASE_URL not set" },
  async () => {
    const { transitionTo } = await import("../lifecycle.ts");
    const { db, capabilityLifecycleEvents } = await import("@workspace/db");
    const { eq } = await import("drizzle-orm");
    const capabilityId = `cap_b1test_${Math.random().toString(16).slice(2, 8)}`;
    const r = await transitionTo({
      capabilityId,
      from: "created",
      to: "cold_start",
      reason: "b1_test",
      payload: { foo: "bar" },
    });
    assert.ok(r.eventId);
    const rows = await db
      .select()
      .from(capabilityLifecycleEvents)
      .where(eq(capabilityLifecycleEvents.id, r.eventId));
    assert.equal(rows.length, 1);
    assert.equal(rows[0]!.capabilityId, capabilityId);
    assert.equal(rows[0]!.toState, "cold_start");
    assert.equal(rows[0]!.reason, "b1_test");
    // cleanup
    await db
      .delete(capabilityLifecycleEvents)
      .where(eq(capabilityLifecycleEvents.id, r.eventId));
  },
);

test(
  "lifecycle: transitionTo throws on illegal transition (no row written)",
  { skip: SKIP_DB && "DATABASE_URL not set" },
  async () => {
    const { transitionTo } = await import("../lifecycle.ts");
    await assert.rejects(
      () =>
        transitionTo({
          capabilityId: "cap_b1test_illegal",
          from: "created",
          to: "live",
          reason: "should_fail",
        }),
      (err: unknown) => err instanceof IllegalLifecycleTransitionError,
    );
  },
);