import { assert } from "https://deno.land/std@0.224.0/assert/mod.ts";

/**
 * Proof of Concept: State Machine (Gen 2)
 *
 * Demonstrates Bounded Model Checking (BMC) for pipeline governance by actually
 * reading and parsing a transitions.json file from the filesystem.
 */

interface TransitionRule {
  requires: string[];
}
type TransitionsConfig = Record<string, TransitionRule>;

function canAgentExecute(
  roleName: string,
  config: TransitionsConfig,
  currentState: Set<string>,
): boolean {
  const rule = config[roleName];
  if (!rule) {
    throw new Error(`Role ${roleName} is not defined in the transitions matrix. Execution denied.`);
  }
  return rule.requires.every((req) => currentState.has(req));
}

if (import.meta.main) {
  console.log("Running State Machine PoC (Gen 2) tests...");

  try {
    const tempFile = await Deno.makeTempFile({ suffix: ".json" });
    await Deno.writeTextFile(tempFile, JSON.stringify({
      "Coder": { "requires": ["Gatekeeper_Approval"] },
      "Gatekeeper": { "requires": [] },
      "Evaluator": { "requires": ["Coder_Completion"] }
    }));

    const matrix: TransitionsConfig = JSON.parse(await Deno.readTextFile(tempFile));
    await Deno.remove(tempFile);

    const currentState = new Set<string>();

    assert(canAgentExecute("Coder", matrix, currentState) === false);
    assert(canAgentExecute("Gatekeeper", matrix, currentState) === true);

    currentState.add("Gatekeeper_Approval");
    assert(canAgentExecute("Coder", matrix, currentState) === true);
    assert(canAgentExecute("Evaluator", matrix, currentState) === false);

    console.log("✅ State Machine PoC (Gen 2) successful: Real File I/O BMC constraints enforced.");
  } catch (err) {
    console.error("❌ State Machine PoC (Gen 2) failed:", err);
    Deno.exit(1);
  }
}