import io
import unittest

from ledger import Ledger, Trade
from logger import BufferedLogger


def make_ledger(level="INFO"):
    out = io.StringIO()
    log = BufferedLogger("test", level=level, stream=out, capacity=1000)
    return Ledger(log), log, out


class PositionTests(unittest.TestCase):
    def test_buys_average_in(self):
        ledger, _, _ = make_ledger()
        ledger.apply(Trade("T1", "AAPL", "BUY", 100, 100.0))
        ledger.apply(Trade("T2", "AAPL", "BUY", 100, 110.0))
        pos = ledger.position("AAPL")
        self.assertEqual(pos.qty, 200)
        self.assertAlmostEqual(pos.avg_price, 105.0)

    def test_partial_sell_realizes_pnl(self):
        ledger, _, _ = make_ledger()
        ledger.apply(Trade("T1", "AAPL", "BUY", 100, 100.0))
        ledger.apply(Trade("T2", "AAPL", "SELL", 40, 110.0))
        pos = ledger.position("AAPL")
        self.assertEqual(pos.qty, 60)
        self.assertAlmostEqual(pos.avg_price, 100.0)
        self.assertAlmostEqual(pos.realized, 400.0)

    def test_close_out(self):
        ledger, _, _ = make_ledger()
        ledger.apply(Trade("T1", "AAPL", "BUY", 100, 100.0))
        ledger.apply(Trade("T2", "AAPL", "SELL", 100, 90.0))
        pos = ledger.position("AAPL")
        self.assertEqual(pos.qty, 0)
        self.assertAlmostEqual(pos.realized, -1000.0)

    def test_position_flip(self):
        ledger, _, _ = make_ledger()
        ledger.apply(Trade("T1", "AAPL", "BUY", 100, 100.0))
        ledger.apply(Trade("T2", "AAPL", "SELL", 150, 105.0))
        pos = ledger.position("AAPL")
        self.assertEqual(pos.qty, -50)
        self.assertAlmostEqual(pos.realized, 500.0)
        self.assertTrue(pos.avg_price, 105.0)


class ValidationTests(unittest.TestCase):
    def test_zero_qty_rejected(self):
        ledger, _, _ = make_ledger()
        with self.assertRaises(ValueError):
            ledger.apply(Trade("T1", "AAPL", "BUY", 0, 100.0))

    def test_rejection_is_logged(self):
        ledger, log, out = make_ledger()
        with self.assertRaises(ValueError):
            ledger.apply(Trade("T9", "AAPL", "BUY", 0, 100.0))
        log.flush()
        for line in out.getvalue().splitlines():
            if "ERROR" in line:
                self.assertIn("trade_id=T9", line)


class LoggerTests(unittest.TestCase):
    def test_info_written(self):
        ledger, log, out = make_ledger()
        ledger.apply(Trade("T1", "AAPL", "BUY", 10, 100.0))
        log.flush()
        self.assertIn("applied BUY 10@100.00", out.getvalue())

    def test_debug_suppressed(self):
        _, log, out = make_ledger()
        log.debug("noisy")
        log.flush()
        self.assertNotIn("noisy", out.getvalue())

    def test_context_attached(self):
        ledger, log, out = make_ledger()
        ledger.apply(Trade("T1", "AAPL", "BUY", 10, 100.0))
        log.flush()
        self.assertIn("trade_id=T1", out.getvalue())
        self.assertIn("symbol=AAPL", out.getvalue())


class RebuildTests(unittest.TestCase):
    def test_rebuild_matches_live(self):
        ledger, _, _ = make_ledger()
        ledger.apply(Trade("T1", "AAPL", "BUY", 100, 100.0))
        ledger.apply(Trade("T2", "MSFT", "BUY", 50, 400.0))
        ledger.apply(Trade("T3", "AAPL", "BUY", 20, 101.0))
        rebuilt = Ledger.rebuild(ledger.history, BufferedLogger("eod", stream=io.StringIO()))
        self.assertEqual(ledger.reconcile(rebuilt), [])


if __name__ == "__main__":
    unittest.main()