"""Tests for `app.engine.sse.SseEmitter`."""

from __future__ import annotations

import asyncio

import pytest

from app.engine.sse import SseEmitter


@pytest.mark.asyncio
async def test_emitter_yields_emitted_events():
    emitter = SseEmitter()
    await emitter.emit("tool_call", {"tool": "calc"})
    await emitter.emit("phase_end", {"phase": 1})
    await emitter.done({"result": "ok"})

    events = []
    async for evt in emitter.stream():
        events.append(evt)
    assert len(events) == 3
    assert events[0]["event"] == "tool_call"
    assert events[1]["event"] == "phase_end"
    assert events[2]["event"] == "done"


@pytest.mark.asyncio
async def test_emitter_event_ids_increment():
    emitter = SseEmitter()
    await emitter.emit("a", {})
    await emitter.emit("b", {})
    events = []
    async for evt in emitter.stream():
        events.append(evt)
    # IDs are evt_1, evt_2 (sentinel None doesn't yield an event)
    assert events[0]["id"] == "evt_1"
    assert events[1]["id"] == "evt_2"


@pytest.mark.asyncio
async def test_emitter_error_closes_stream():
    emitter = SseEmitter()
    await emitter.error("test_error", "something went wrong", details={"k": "v"})
    events = []
    async for evt in emitter.stream():
        events.append(evt)
    assert len(events) == 1
    assert events[0]["event"] == "error"
    import json
    payload = json.loads(events[0]["data"])
    assert payload["code"] == "test_error"
    assert payload["details"] == {"k": "v"}


@pytest.mark.asyncio
async def test_emitter_done_with_no_result():
    emitter = SseEmitter()
    await emitter.done()
    events = []
    async for evt in emitter.stream():
        events.append(evt)
    assert len(events) == 1
    assert events[0]["event"] == "done"


@pytest.mark.asyncio
async def test_emitter_serializes_non_serializable_data():
    emitter = SseEmitter()
    # A set is not JSON-serializable
    await emitter.emit("test", {"data": {1, 2, 3}})
    await emitter.done()
    events = []
    async for evt in emitter.stream():
        events.append(evt)
    # The first event should still have valid JSON (with serialization fallback)
    import json
    payload = json.loads(events[0]["data"])
    assert "error" in payload or "data" in payload