import { describe, it, expect, beforeEach, afterEach } from "vitest";
import * as fs from "node:fs";
import * as os from "node:os";
import * as path from "node:path";
import { BaselineStore, normalizeReason, type Baseline } from "../src/baselineStore";

let dir: string;

beforeEach(() => {
  dir = fs.mkdtempSync(path.join(os.tmpdir(), "baseline-store-"));
});
afterEach(() => {
  fs.rmSync(dir, { recursive: true, force: true });
});

const KEY = "a1b2c3"; // a stand-in for the controller's sha256(uri) key

function sample(uri = "file:///ws/notes/chapter-1.md"): Baseline {
  return { uri, text: "hello\nworld\n", capturedAt: "2026-06-11T00:00:00.000Z", reason: "entered" };
}

describe("normalizeReason (INV-7 legacy migration)", () => {
  it("migrates legacy 'opened' → 'entered'", () => {
    expect(normalizeReason("opened")).toBe("entered");
  });
  it("migrates legacy 'machine-landing' → 'entered'", () => {
    expect(normalizeReason("machine-landing")).toBe("entered");
  });
  it("passes current reasons through unchanged", () => {
    expect(normalizeReason("entered")).toBe("entered");
    expect(normalizeReason("pinned")).toBe("pinned");
    expect(normalizeReason("head")).toBe("head");
  });
});

describe("BaselineStore", () => {
  it("returns null for a key with no baseline", () => {
    expect(new BaselineStore(dir).load(KEY)).toBeNull();
  });

  it("computes the baseline path as baselines/<key>.json", () => {
    const store = new BaselineStore(dir);
    expect(store.baselinePath(KEY)).toBe(path.join(dir, "baselines", "a1b2c3.json"));
  });

  it("save then load round-trips the baseline (including the uri identity)", () => {
    const store = new BaselineStore(dir);
    const b = sample();
    store.save(KEY, b);
    expect(store.load(KEY)).toEqual(b);
  });

  it("migrates a legacy on-disk reason ('opened') to 'entered' on load", () => {
    const store = new BaselineStore(dir);
    fs.mkdirSync(path.dirname(store.baselinePath(KEY)), { recursive: true });
    fs.writeFileSync(
      store.baselinePath(KEY),
      JSON.stringify({ uri: "file:///a.md", text: "legacy\n", capturedAt: "2026-06-11T00:00:00.000Z", reason: "opened" }),
      "utf8",
    );
    expect(store.load(KEY)?.reason).toBe("entered");
  });

  it("migrates a legacy on-disk reason ('machine-landing') to 'entered' on load", () => {
    const store = new BaselineStore(dir);
    fs.mkdirSync(path.dirname(store.baselinePath(KEY)), { recursive: true });
    fs.writeFileSync(
      store.baselinePath(KEY),
      JSON.stringify({ uri: "file:///a.md", text: "legacy\n", capturedAt: "2026-06-11T00:00:00.000Z", reason: "machine-landing" }),
      "utf8",
    );
    expect(store.load(KEY)?.reason).toBe("entered");
  });

  it("overwrites in place: the newest epoch wins, no history kept", () => {
    const store = new BaselineStore(dir);
    store.save(KEY, { uri: "untitled:Untitled-1", text: "v1", capturedAt: "2026-06-11T00:00:00.000Z", reason: "entered" });
    store.save(KEY, { uri: "untitled:Untitled-1", text: "v2", capturedAt: "2026-06-11T00:01:00.000Z", reason: "pinned" });
    expect(store.load(KEY)).toEqual({ uri: "untitled:Untitled-1", text: "v2", capturedAt: "2026-06-11T00:01:00.000Z", reason: "pinned" });
  });

  it("writes pretty JSON with a trailing newline", () => {
    const store = new BaselineStore(dir);
    const b = sample();
    store.save(KEY, b);
    const raw = fs.readFileSync(store.baselinePath(KEY), "utf8");
    expect(raw).toBe(JSON.stringify(b, null, 2) + "\n");
  });

  it("distinct keys are independent files (no collision)", () => {
    const store = new BaselineStore(dir);
    store.save("k1", sample("file:///a.md"));
    store.save("k2", sample("file:///b.md"));
    expect(store.load("k1")!.uri).toBe("file:///a.md");
    expect(store.load("k2")!.uri).toBe("file:///b.md");
  });
});