import { describe, it, expect } from "@jest/globals";
import {
  ALLOWED_TRANSITIONS,
  ROLE_FOR_TRANSITION,
  SOD_REQUIRED_TRANSITIONS,
  TRANSACTION_STATES,
  canTransition,
} from "../../src/types/transactionState";

describe("Transaction state machine (architecture note §8–§9)", () => {
  it("declares the 12 states from §8.1", () => {
    expect(TRANSACTION_STATES).toEqual([
      "DRAFT",
      "INITIATED",
      "PRECONDITIONS_PENDING",
      "READY_FOR_PREPARE",
      "PREPARED",
      "EXECUTING",
      "PARTIALLY_EXECUTED",
      "VALIDATING",
      "COMMITTED",
      "ABORTED",
      "UNWIND_PENDING",
      "CLOSED",
    ]);
  });

  describe("§9.1 permitted high-level transitions", () => {
    // Each of these is listed in the note; canTransition must accept them.
    const legal: Array<[string, string]> = [
      ["DRAFT", "INITIATED"],
      ["INITIATED", "PRECONDITIONS_PENDING"],
      ["PRECONDITIONS_PENDING", "READY_FOR_PREPARE"],
      ["READY_FOR_PREPARE", "PREPARED"],
      ["PREPARED", "EXECUTING"],
      ["EXECUTING", "PARTIALLY_EXECUTED"],
      ["EXECUTING", "VALIDATING"],
      ["PARTIALLY_EXECUTED", "VALIDATING"],
      ["VALIDATING", "COMMITTED"],
      ["VALIDATING", "ABORTED"],
      ["ABORTED", "UNWIND_PENDING"],
      ["COMMITTED", "CLOSED"],
      ["UNWIND_PENDING", "CLOSED"],
    ];
    it.each(legal)("allows %s -> %s", (from, to) => {
      expect(canTransition(from as any, to as any)).toBe(true);
    });

    // A few illegal edges — explicitly not in §9.1.
    const illegal: Array<[string, string]> = [
      ["DRAFT", "COMMITTED"],
      ["INITIATED", "EXECUTING"],
      ["CLOSED", "INITIATED"],
      ["PREPARED", "COMMITTED"],
      ["COMMITTED", "ABORTED"],
      ["ABORTED", "COMMITTED"],
    ];
    it.each(illegal)("rejects %s -> %s", (from, to) => {
      expect(canTransition(from as any, to as any)).toBe(false);
    });
  });

  it("CLOSED is a terminal state", () => {
    expect(ALLOWED_TRANSITIONS.CLOSED).toEqual([]);
  });

  describe("segregation-of-duties checkpoints (§13)", () => {
    it("flags the four SoD-gated transitions", () => {
      expect([...SOD_REQUIRED_TRANSITIONS].sort()).toEqual(
        [
          "ABORTED->UNWIND_PENDING",
          "PREPARED->EXECUTING",
          "READY_FOR_PREPARE->PREPARED",
          "VALIDATING->COMMITTED",
        ].sort(),
      );
    });

    it("assigns a role to every SoD-gated transition", () => {
      for (const key of SOD_REQUIRED_TRANSITIONS) {
        expect(ROLE_FOR_TRANSITION[key]).toBeDefined();
      }
    });
  });
});