"""
Tests for backend/main.py — FastAPI endpoints.

Covers:
  - Ticker input validation (valid + invalid)
  - DEMO_MODE staging response
  - Rate limiting logic
  - Quick signal caching
  - HTTP method restrictions
"""
import json
import time
import pytest
from unittest.mock import patch, MagicMock, AsyncMock
from fastapi.testclient import TestClient


# ── Fixture helpers ────────────────────────────────────────────────────────────

def _make_client(demo_mode: bool = False):
    """Import app fresh with the desired DEMO_MODE."""
    import importlib
    import sys

    # Patch env before importing app
    env_patch = {
        "DEMO_MODE": "true" if demo_mode else "false",
        "LLM_MODE":  "cloud",
    }
    with patch.dict("os.environ", env_patch):
        # Force re-import so DEMO_MODE constant is re-evaluated
        for mod in list(sys.modules.keys()):
            if "backend.main" in mod or mod == "backend.main":
                del sys.modules[mod]
        import backend.main as app_module  # noqa: PLC0415
        importlib.reload(app_module)
        return TestClient(app_module.app), app_module


# ── Ticker validation ─────────────────────────────────────────────────────────

class TestTickerValidation:
    def setup_method(self):
        self.client, self.mod = _make_client()

    @pytest.mark.parametrize("ticker", [
        "AAPL", "NVDA", "BRK.B", "SPY", "QQQ", "BP", "HSBA",
    ])
    def test_valid_tickers_accepted_quick(self, ticker):
        with patch.object(self.mod, "fuse_signals", return_value={"recommendation": "BUY"}):
            r = self.client.get(f"/quick/{ticker}")
        assert r.status_code != 400, f"Valid ticker {ticker} was rejected"

    @pytest.mark.parametrize("bad", [
        "../etc",          # path traversal attempt
        "A" * 11,          # too long
        "DROP;TABLE",      # injection attempt
        "<script>",        # XSS attempt
        "",                # empty (handled by route matching)
    ])
    def test_invalid_tickers_rejected_quick(self, bad):
        r = self.client.get(f"/quick/{bad}")
        # Path-traversal attempts ('../etc') are normalised by Starlette → 404;
        # other invalid inputs reach our validator and return 400.
        # Either way the request must NOT succeed (not 200).
        assert r.status_code in (400, 404)

    @pytest.mark.parametrize("bad", [
        "../etc",
        "A" * 11,
        "'; DROP TABLE--",
        "<img src=x>",
    ])
    def test_invalid_tickers_rejected_stream(self, bad):
        r = self.client.get(f"/stream/{bad}")
        assert r.status_code in (400, 404)


# ── Demo mode ─────────────────────────────────────────────────────────────────

class TestDemoMode:
    def setup_method(self):
        self.client, self.mod = _make_client(demo_mode=True)

    def test_stream_returns_demo_event(self):
        r = self.client.get("/stream/AAPL")
        assert r.status_code == 200
        lines = [l for l in r.text.splitlines() if l.startswith("data:")]
        events = [json.loads(l[6:]) for l in lines if l[6:].strip() != "[DONE]"]
        assert len(events) == 1
        assert events[0].get("demo") is True
        assert "Private Beta" in events[0]["content"]

    def test_stream_demo_does_not_call_llm(self):
        # In DEMO_MODE the endpoint returns a staged response before ever
        # reaching the orchestrator — verify no LLM-related error key is present.
        r = self.client.get("/stream/AAPL")
        assert r.status_code == 200
        body = r.text
        assert "error" not in body.lower() or "Private Beta" in body


# ── Rate limiting ─────────────────────────────────────────────────────────────

class TestRateLimiting:
    def setup_method(self):
        self.client, self.mod = _make_client(demo_mode=False)
        self.mod._IP_LAST_RUN.clear()
        self.mod._STREAM_CACHE.clear()

    def test_first_request_allowed(self):
        # Seed the cache so the endpoint serves the cached path
        # (orchestrator is not imported in main.py yet — cache path is safe)
        self.mod._STREAM_CACHE["AAPL"] = (
            time.time(),
            [{"agent": "test", "content": "cached"}],
        )
        r = self.client.get("/stream/AAPL")
        assert r.status_code != 429

    def test_second_request_within_window_rate_limited(self):
        # Simulate a recent run from this IP
        ip = "testclient"
        self.mod._IP_LAST_RUN[ip] = time.time()

        r = self.client.get("/stream/MSFT")
        assert r.status_code == 429
        body = r.json()
        assert "retry_after" in body

    def test_cache_hit_bypasses_rate_limit(self):
        ip = "testclient"
        # Rate-limited IP
        self.mod._IP_LAST_RUN[ip] = time.time()
        # But ticker is cached
        self.mod._STREAM_CACHE["AAPL"] = (
            time.time(),
            [{"agent": "test", "content": "cached result"}],
        )
        r = self.client.get("/stream/AAPL")
        assert r.status_code == 200
        assert "cached result" in r.text


# ── Quick signal caching ──────────────────────────────────────────────────────

class TestQuickCache:
    def setup_method(self):
        self.client, self.mod = _make_client()
        self.mod._QUICK_CACHE.clear()

    def test_cache_miss_calls_fuse_signals(self):
        with patch.object(self.mod, "fuse_signals", return_value={"recommendation": "BUY"}) as mock:
            self.client.get("/quick/TSLA")
        mock.assert_called_once_with("TSLA")

    def test_cache_hit_does_not_call_fuse_signals(self):
        self.mod._QUICK_CACHE["NVDA"] = (time.time(), {"recommendation": "HOLD"})
        with patch.object(self.mod, "fuse_signals") as mock:
            r = self.client.get("/quick/NVDA")
        mock.assert_not_called()
        assert r.json()["recommendation"] == "HOLD"

    def test_stale_cache_refreshes(self):
        stale_ts = time.time() - (self.mod._QUICK_TTL + 60)
        self.mod._QUICK_CACHE["GOOG"] = (stale_ts, {"recommendation": "OLD"})
        with patch.object(self.mod, "fuse_signals", return_value={"recommendation": "SELL"}):
            r = self.client.get("/quick/GOOG")
        assert r.json()["recommendation"] == "SELL"


# ── Portfolio endpoint ────────────────────────────────────────────────────────

class TestPortfolioEndpoint:
    def setup_method(self):
        self.client, self.mod = _make_client()

    def test_portfolio_returns_summary(self):
        holdings = [
            {"ticker": "AAPL", "name": "Apple", "sector": "Tech",
             "asset_class": "Equity", "pct_of_portfolio": 10},
        ]
        with patch.object(self.mod, "get_holdings", return_value=holdings), \
             patch.object(self.mod, "fuse_signals", return_value={
                 "recommendation": "BUY", "confidence": 0.8,
                 "final_score": 0.7, "current_price": 190.0, "risk_flags": [],
             }):
            r = self.client.get("/portfolio")
        assert r.status_code == 200
        body = r.json()
        assert "holdings" in body
        assert "summary" in body
        assert body["summary"]["total"] == 1
        assert body["summary"]["buy"] == 1

    def test_portfolio_handles_fuse_error(self):
        holdings = [{"ticker": "BAD", "name": "Bad Co", "sector": "",
                     "asset_class": "", "pct_of_portfolio": 5}]
        with patch.object(self.mod, "get_holdings", return_value=holdings), \
             patch.object(self.mod, "fuse_signals", side_effect=Exception("connection error")):
            r = self.client.get("/portfolio")
        assert r.status_code == 200
        assert r.json()["holdings"][0]["recommendation"] == "HOLD"


# ── HTTP method restrictions ──────────────────────────────────────────────────

class TestMethodRestrictions:
    def setup_method(self):
        self.client, _ = _make_client()

    @pytest.mark.parametrize("path", ["/quick/AAPL", "/stream/AAPL", "/portfolio"])
    def test_post_not_allowed(self, path):
        r = self.client.post(path)
        assert r.status_code == 405

    @pytest.mark.parametrize("path", ["/quick/AAPL", "/stream/AAPL", "/portfolio"])
    def test_delete_not_allowed(self, path):
        r = self.client.delete(path)
        assert r.status_code == 405