"""Tests for WS folder index_session handlers (Task 9).

Tests the three handler functions directly with a minimal fake WebSocket so
no real WS connection or LLM call is made.
"""

from __future__ import annotations

import json
from datetime import datetime, timezone
from unittest.mock import AsyncMock, patch

import pytest
import pytest_asyncio

from app.api.routes.device_ws import (
    _handle_index_session_start,
    _handle_index_file_batch,
    _handle_index_session_cancel,
    _index_sessions,
)
from app.billing.quota import add_token_usage
from app.core.folder_indexer import IndexResult
from app.models import MonthlyTokenUsage
from app.schemas import WsFrameType
from tests.conftest import TEST_USER_IDS

pytestmark = pytest.mark.asyncio

USER_ID = TEST_USER_IDS["free"]
POWER_USER_ID = TEST_USER_IDS["power"]


# ── Fake WebSocket ────────────────────────────────────────────────────

class _FakeWebSocket:
    """Minimal WebSocket stand-in that records send_text calls."""

    def __init__(self) -> None:
        self.sent: list[dict] = []

    async def send_text(self, text: str) -> None:
        self.sent.append(json.loads(text))

    def sent_types(self) -> list[str]:
        return [f["type"] for f in self.sent]


# ── Helpers ───────────────────────────────────────────────────────────

def _make_session_id() -> str:
    import uuid
    return str(uuid.uuid4())


def _fake_summarize_text_factory(summary: str = "A test summary.", tokens: int = 100):
    """Return an AsyncMock that resolves to a fixed IndexResult."""
    async def _fake(**kwargs) -> IndexResult:
        return IndexResult(summary=summary, tokens_used=tokens)
    return _fake


# ── Fixtures ──────────────────────────────────────────────────────────

@pytest_asyncio.fixture(autouse=True)
async def _clean_sessions():
    """Ensure _index_sessions is empty before and after each test."""
    _index_sessions.clear()
    yield
    _index_sessions.clear()


# ── Tests ─────────────────────────────────────────────────────────────

async def test_index_session_happy_path(db_session):
    """start + batch of 2 text files → 2 index_file_result + 1 progress + 1 done(completed)."""
    ws = _FakeWebSocket()
    session_id = _make_session_id()

    # Register session.
    await _handle_index_session_start(ws, USER_ID, {
        "sessionId": session_id,
        "projectId": "proj-1",
        "totalFiles": 2,
    })

    # Verify session was registered.
    assert session_id in _index_sessions
    assert _index_sessions[session_id]["total"] == 2
    assert _index_sessions[session_id]["processed"] == 0
    # No response frames expected for session_start.
    assert ws.sent == []

    # Send batch of 2 text files — patch summarize_text so no LLM call needed.
    with patch(
        "app.api.routes.device_ws._handle_index_file_batch.__globals__",
        # We patch the module-level function in folder_indexer instead:
    ) if False else patch("app.core.folder_indexer.summarize_text", side_effect=_fake_summarize_text_factory()):
        with patch("app.api.routes.device_ws.async_session") as mock_async_session:
            # Wire db_session into the context manager.
            mock_cm = AsyncMock()
            mock_cm.__aenter__ = AsyncMock(return_value=db_session)
            mock_cm.__aexit__ = AsyncMock(return_value=False)
            mock_async_session.return_value = mock_cm

            await _handle_index_file_batch(ws, USER_ID, {
                "sessionId": session_id,
                "files": [
                    {"relPath": "README.md", "kind": "text", "content": "hello", "ext": ".md"},
                    {"relPath": "notes.txt", "kind": "text", "content": "world", "ext": ".txt"},
                ],
            })

    types = ws.sent_types()
    # Expect 2 file results + 1 progress + 1 done(completed).
    assert types.count(WsFrameType.index_file_result) == 2
    assert types.count(WsFrameType.index_session_progress) == 1
    assert types.count(WsFrameType.index_session_done) == 1

    done_frame = next(f for f in ws.sent if f["type"] == WsFrameType.index_session_done)
    assert done_frame["status"] == "completed"

    progress_frame = next(f for f in ws.sent if f["type"] == WsFrameType.index_session_progress)
    assert progress_frame["processed"] == 2
    assert progress_frame["total"] == 2

    # Verify session cleaned up.
    assert session_id not in _index_sessions


async def test_index_session_cancel(db_session):
    """start then cancel → index_session_done(cancelled)."""
    ws = _FakeWebSocket()
    session_id = _make_session_id()

    await _handle_index_session_start(ws, USER_ID, {
        "sessionId": session_id,
        "totalFiles": 5,
    })
    assert session_id in _index_sessions

    await _handle_index_session_cancel(ws, {"sessionId": session_id})

    types = ws.sent_types()
    assert WsFrameType.index_session_done in types
    done_frame = next(f for f in ws.sent if f["type"] == WsFrameType.index_session_done)
    assert done_frame["status"] == "cancelled"

    # Session should be cleaned up.
    assert session_id not in _index_sessions


async def test_index_session_quota_exceeded(db_session):
    """Pre-fill usage to cap → batch one file → index_session_done(quota_exceeded)."""
    ws = _FakeWebSocket()
    session_id = _make_session_id()

    # Pre-fill monthly token usage to the free-tier cap (100_000).
    ym = datetime.now(timezone.utc).strftime("%Y-%m")
    db_session.add(MonthlyTokenUsage(
        user_id=USER_ID,
        year_month=ym,
        feature="folder_index",
        tokens_used=100_000,  # free tier cap exactly
    ))
    await db_session.commit()

    await _handle_index_session_start(ws, USER_ID, {
        "sessionId": session_id,
        "totalFiles": 1,
    })

    with patch("app.core.folder_indexer.summarize_text", side_effect=_fake_summarize_text_factory(tokens=1)):
        with patch("app.api.routes.device_ws.async_session") as mock_async_session:
            mock_cm = AsyncMock()
            mock_cm.__aenter__ = AsyncMock(return_value=db_session)
            mock_cm.__aexit__ = AsyncMock(return_value=False)
            mock_async_session.return_value = mock_cm

            await _handle_index_file_batch(ws, USER_ID, {
                "sessionId": session_id,
                "files": [
                    {"relPath": "file.md", "kind": "text", "content": "content", "ext": ".md"},
                ],
            })

    types = ws.sent_types()
    # Should have 1 file result (success) then done(quota_exceeded).
    assert WsFrameType.index_file_result in types
    assert WsFrameType.index_session_done in types

    done_frame = next(f for f in ws.sent if f["type"] == WsFrameType.index_session_done)
    assert done_frame["status"] == "quota_exceeded"

    # Session should be cleaned up.
    assert session_id not in _index_sessions