import { describe, expect, it } from "vitest";
import { MAX_TOOL_RUNS, recordToolRun, readToolHistory, type ToolRunMetadata } from "../src/tool-history";

function createStorage(seed: string | null = null) {
  let value = seed;
  return {
    getItem: () => value,
    setItem: (_key: string, next: string) => { value = next; },
    value: () => value,
  };
}

const run = (overrides: Partial<ToolRunMetadata> = {}): ToolRunMetadata => ({
  tool: "gitea.pullrequest.status",
  project: "ludarium",
  environment: "prod",
  ok: true,
  traceId: "trace-123",
  at: "2026-09-30T10:00:00.000Z",
  ...overrides,
});

describe("bounded recent tool history", () => {
  it("stores only safe invocation metadata and never serializes arguments or results", () => {
    const storage = createStorage();
    recordToolRun({ ...run(), arguments: { token: "fixture-do-not-store" }, result: "private output" } as ToolRunMetadata, storage);

    expect(JSON.parse(storage.value() ?? "null")).toEqual([run()]);
    expect(storage.value()).not.toContain("fixture-do-not-store");
    expect(storage.value()).not.toContain("private output");
  });

  it("bounds history to the newest twenty valid entries", () => {
    const storage = createStorage();
    for (let index = 0; index < MAX_TOOL_RUNS + 4; index += 1) {
      recordToolRun(run({ traceId: `trace-${index}`, at: `2026-09-30T10:${String(index).padStart(2, "0")}:00.000Z` }), storage);
    }

    const history = readToolHistory(storage);
    expect(history).toHaveLength(MAX_TOOL_RUNS);
    expect(history[0]?.traceId).toBe(`trace-${MAX_TOOL_RUNS + 3}`);
    expect(history.at(-1)?.traceId).toBe("trace-4");
  });

  it("drops malformed and oversized stored entries without exposing extra fields", () => {
    const storage = createStorage(JSON.stringify([
      { ...run(), arguments: { apiKey: "secret" }, content: "result" },
      { ...run(), traceId: "trace\nsecret" },
      { ...run(), at: "yesterday" },
      null,
    ]));

    expect(readToolHistory(storage)).toEqual([run()]);
  });

  it("treats corrupt or unavailable browser storage as an empty history", () => {
    expect(readToolHistory(createStorage("not-json"))).toEqual([]);
    expect(() => readToolHistory({ getItem: () => { throw new Error("blocked"); }, setItem: () => undefined })).not.toThrow();
    expect(() => recordToolRun(run(), { getItem: () => null, setItem: () => { throw new Error("blocked"); } })).not.toThrow();
  });
});