/**
 * @file replay.test.ts
 * @description Unit tests for the Replay tab's pure derivations: playback
 * order, lifecycle markers and the session state at a cursor.
 * @author Nguyễn Ngọc Trí Vĩ <vinnt@smartgift.vn>
 */

import { describe, it, expect } from "vitest";
import { chronological, lifecycleMarkers, replayState } from "../replay";
import type { DashboardEvent } from "../types";

let nextId = 1;
function ev(event_type: string, sec: number, tool_name: string | null = null, agent = "main") {
  return {
    id: nextId++,
    session_id: "s",
    agent_id: agent,
    event_type,
    tool_name,
    summary: null,
    data: null,
    created_at: new Date(Date.UTC(2026, 9, 1, 10, 0, sec)).toISOString(),
  } as unknown as DashboardEvent;
}

const events = [
  ev("SessionStart", 0),
  ev("UserPromptSubmit", 1),
  ev("PreToolUse", 2, "Read"),
  ev("PostToolUse", 3, "Read"),
  ev("PreToolUse", 4, "Bash"),
  ev("PreToolUse", 5, "Read", "sub"),
  ev("APIError", 6),
  ev("PostToolUse", 7, "Bash"),
  ev("Stop", 8),
];

describe("chronological", () => {
  it("orders by time, then id", () => {
    const tie = [ev("Stop", 9), ev("Stop", 9)];
    const out = chronological([tie[1]!, events[2]!, tie[0]!, events[0]!]);
    expect(out.map((e) => e.id)).toEqual([events[0]!.id, events[2]!.id, tie[0]!.id, tie[1]!.id]);
  });
});

describe("lifecycleMarkers", () => {
  it("marks lifecycle events at their sequence position", () => {
    const m = lifecycleMarkers(events);
    expect(m.map((x) => x.type)).toEqual(["SessionStart", "UserPromptSubmit", "APIError", "Stop"]);
    expect(m[0]!.pct).toBe(0);
    expect(m[3]!.pct).toBe(100);
    expect(m[2]!.index).toBe(6);
  });

  it("handles a single event", () => {
    expect(lifecycleMarkers([events[0]!])).toEqual([{ index: 0, type: "SessionStart", pct: 0 }]);
  });
});

describe("replayState", () => {
  it("is empty for no events", () => {
    const s = replayState([], 0);
    expect(s.status).toBeNull();
    expect(s.currentTool).toBeNull();
    expect(s.toolCounts).toEqual([]);
  });

  it("tracks the tool in flight and counts up to the cursor", () => {
    const at4 = replayState(events, 4);
    expect(at4.currentTool).toBe("Bash");
    expect(at4.status).toBe("working");
    expect(at4.prompts).toBe(1);
    expect(at4.toolCounts).toEqual([
      { tool: "Bash", count: 1 },
      { tool: "Read", count: 1 },
    ]);
    expect(at4.elapsedMs).toBe(4000);

    const at6 = replayState(events, 6);
    expect(at6.currentTool).toBe("Read"); // the subagent's, newest still open
    expect(at6.errors).toBe(1);
    expect(at6.status).toBe("error");
    expect(at6.toolCounts[0]).toEqual({ tool: "Read", count: 2 });
  });

  it("closes a finished tool and an ended turn", () => {
    expect(replayState(events, 3).currentTool).toBeNull();
    // Stop on main leaves only the subagent's Read open.
    expect(replayState(events, 8).currentTool).toBe("Read");
    expect(replayState(events, 8).status).toBe("waiting");
  });

  it("clamps a cursor past the end", () => {
    expect(replayState(events, 99).elapsedMs).toBe(8000);
  });
});