import assert from "node:assert/strict";
import fs from "node:fs";
import path from "node:path";
import test from "node:test";
import ts from "typescript";

const repoRoot = path.resolve(import.meta.dirname, "../../..");
const sourcePath = path.join(repoRoot, "web/protocol/save-transaction.ts");
const transpiled = ts.transpileModule(fs.readFileSync(sourcePath, "utf8"), {
  compilerOptions: { module: ts.ModuleKind.ES2022, target: ts.ScriptTarget.ES2022 },
  fileName: sourcePath,
  reportDiagnostics: true,
});
assert.deepEqual(transpiled.diagnostics, []);
const moduleUrl = `data:text/javascript;base64,${Buffer.from(transpiled.outputText).toString("base64")}`;
const {
  SAVE_ATTEMPT_STAGES,
  advanceSaveTransaction,
  beginSaveTransaction,
  commitSaveTransaction,
  createSaveTransactionState,
  failSaveTransaction,
} = await import(moduleUrl);

const oldCommit = { revision: 7, sha256: "a".repeat(64) };
const newCommit = { revision: 8, sha256: "b".repeat(64) };

function stateAt(stage) {
  let result = beginSaveTransaction(createSaveTransactionState(oldCommit), newCommit.revision);
  assert.equal(result.ok, true);
  for (const next of SAVE_ATTEMPT_STAGES.slice(1, SAVE_ATTEMPT_STAGES.indexOf(stage) + 1)) {
    result = advanceSaveTransaction(result.state, next, next === "OPFS_STAGE" ? newCommit.sha256 : undefined);
    assert.equal(result.ok, true);
  }
  return result.state;
}

test("M7-05 preserves the old committed identity at every failed save stage", () => {
  for (const stage of SAVE_ATTEMPT_STAGES) {
    const failed = failSaveTransaction(stateAt(stage), `SAVE_${stage}_INTERRUPTED`);
    assert.equal(failed.status, "FAILED");
    assert.equal(failed.stage, stage);
    assert.deepEqual(failed.committed, oldCommit);
    assert.equal(failed.candidate.revision, newCommit.revision);
  }
});

test("M7-05 advances committed revision and hash only after matching metadata commit", () => {
  const metadata = stateAt("METADATA_COMMIT");
  assert.deepEqual(commitSaveTransaction(metadata, { ...newCommit, sha256: "c".repeat(64) }), {
    ok: false,
    state: metadata,
    errorCode: "SAVE_TRANSACTION_COMMIT_MISMATCH",
  });
  const committed = commitSaveTransaction(metadata, newCommit);
  assert.equal(committed.ok, true);
  assert.deepEqual(committed.state.committed, newCommit);
  assert.equal(committed.state.status, "SUCCEEDED");
});

test("M7-05 rejects reentrant and out-of-order save transitions", () => {
  const running = beginSaveTransaction(createSaveTransactionState(oldCommit), 8);
  assert.equal(running.ok, true);
  assert.equal(beginSaveTransaction(running.state, 9).errorCode, "SAVE_TRANSACTION_INVALID_TRANSITION");
  assert.equal(advanceSaveTransaction(running.state, "SCENE_COMMIT").errorCode, "SAVE_TRANSACTION_INVALID_TRANSITION");
});