import os
import contextlib
import io
import json
import unittest
from unittest.mock import patch

from sqlalchemy.exc import OperationalError

os.environ.setdefault("DATABASE_URL", "postgresql+psycopg://user:pass@localhost:5432/ai_ict_test")

from scripts import run_backtest
from scripts.run_backtest import (
    build_backtest_candidate_model_code_from_env,
    build_backtest_session_codes_from_env,
    build_backtest_timeframe_set_from_env,
    build_backtest_mode_from_env,
    build_backtest_subject_type_from_env,
    build_cost_config_from_env,
    build_quality_gate_from_env,
    build_replay_config_from_env,
    build_require_quality_gate_from_env,
    build_backtest_trading_plan_id_from_env,
    run_backtest_once,
)
from src.services.backtest import BacktestOutcome


class RunBacktestScriptTests(unittest.TestCase):
    def test_build_cost_config_from_env_uses_zero_defaults(self) -> None:
        config = build_cost_config_from_env({})

        self.assertEqual(config.fee_rate, 0.0)
        self.assertEqual(config.slippage_rate, 0.0)
        self.assertEqual(config.fixed_cost_r, 0.0)

    def test_empty_env_overrides_ambient_backtest_settings(self) -> None:
        with patch.dict(
            os.environ,
            {
                "BACKTEST_FEE_RATE": "0.02",
                "BACKTEST_REQUIRE_QUALITY_GATE": "1",
                "BACKTEST_MIN_TOTAL_SIGNALS": "999",
                "BACKTEST_MIN_EXECUTED_SIGNALS": "888",
            },
            clear=False,
        ):
            config = build_cost_config_from_env({})
            require_gate = build_require_quality_gate_from_env({})
            gate = build_quality_gate_from_env({})

        self.assertEqual(config.fee_rate, 0.0)
        self.assertFalse(require_gate)
        self.assertNotEqual(gate.min_total_signals, 999)
        self.assertNotEqual(gate.min_executed_signals, 888)

    def test_build_cost_config_from_env_reads_cost_values(self) -> None:
        config = build_cost_config_from_env(
            {
                "BACKTEST_FEE_RATE": "0.0005",
                "BACKTEST_SLIPPAGE_RATE": "0.0007",
                "BACKTEST_FIXED_COST_R": "0.05",
            }
        )

        self.assertEqual(config.fee_rate, 0.0005)
        self.assertEqual(config.slippage_rate, 0.0007)
        self.assertEqual(config.fixed_cost_r, 0.05)

    def test_build_require_quality_gate_from_env(self) -> None:
        self.assertFalse(build_require_quality_gate_from_env({}))
        self.assertFalse(build_require_quality_gate_from_env({"BACKTEST_REQUIRE_QUALITY_GATE": "0"}))
        self.assertTrue(build_require_quality_gate_from_env({"BACKTEST_REQUIRE_QUALITY_GATE": "true"}))
        self.assertTrue(build_require_quality_gate_from_env({"BACKTEST_REQUIRE_QUALITY_GATE": "1"}))

    def test_build_quality_gate_from_env_reads_thresholds(self) -> None:
        gate = build_quality_gate_from_env(
            {
                "BACKTEST_MIN_TOTAL_SIGNALS": "50",
                "BACKTEST_MIN_EXECUTED_SIGNALS": "20",
                "BACKTEST_MIN_EXPECTANCY_R": "0.1",
                "BACKTEST_MIN_PROFIT_FACTOR_R": "1.5",
                "BACKTEST_MAX_DRAWDOWN_R": "6.0",
                "BACKTEST_MAX_CONSECUTIVE_LOSSES": "3",
            }
        )

        self.assertEqual(gate.min_total_signals, 50)
        self.assertEqual(gate.min_executed_signals, 20)
        self.assertEqual(gate.min_expectancy_r, 0.1)
        self.assertEqual(gate.min_profit_factor_r, 1.5)
        self.assertEqual(gate.max_drawdown_r, 6.0)
        self.assertEqual(gate.max_consecutive_losses, 3)

    def test_build_backtest_mode_and_replay_config_from_env(self) -> None:
        self.assertEqual(build_backtest_mode_from_env({}), "entry_then_outcome")
        self.assertEqual(build_backtest_mode_from_env({"BACKTEST_MODE": "replay_no_lookahead"}), "replay_no_lookahead")
        self.assertEqual(build_backtest_subject_type_from_env({}), "plan_replay")
        self.assertEqual(build_backtest_subject_type_from_env({"BACKTEST_SUBJECT_TYPE": "signal"}), "signal")
        self.assertEqual(build_backtest_subject_type_from_env({"BACKTEST_SESSION_CODES": "LONDON"}), "signal")
        self.assertIsNone(build_backtest_trading_plan_id_from_env({}))
        self.assertEqual(build_backtest_trading_plan_id_from_env({"BACKTEST_TRADING_PLAN_ID": "77"}), 77)
        self.assertIsNone(build_backtest_candidate_model_code_from_env({}))
        self.assertEqual(build_backtest_candidate_model_code_from_env({"BACKTEST_CANDIDATE_MODEL_CODE": "OSOK"}), "OSOK")
        self.assertEqual(build_backtest_session_codes_from_env({}), [])
        self.assertEqual(build_backtest_session_codes_from_env({"BACKTEST_SESSION_CODES": "LONDON,NY_AM"}), ["LONDON", "NY_AM"])

        replay_config = build_replay_config_from_env(
            {
                "BACKTEST_REPLAY_LEFT_BARS": "1",
                "BACKTEST_REPLAY_RIGHT_BARS": "3",
            }
        )

        self.assertEqual(replay_config.left_bars, 1)
        self.assertEqual(replay_config.right_bars, 3)

    def test_build_backtest_timeframe_set_from_env(self) -> None:
        self.assertEqual(
            build_backtest_timeframe_set_from_env({}),
            {"bias_tf": "1m", "setup_tf": "1m", "trigger_tf": "1m"},
        )
        self.assertEqual(
            build_backtest_timeframe_set_from_env(
                {
                    "AI_ICT_BIAS_TIMEFRAME": "1h",
                    "AI_ICT_SETUP_TIMEFRAME": "15m",
                    "AI_ICT_TRIGGER_TIMEFRAME": "5m",
                }
            ),
            {"bias_tf": "1h", "setup_tf": "15m", "trigger_tf": "5m"},
        )

    def test_run_backtest_once_allows_failed_quality_gate_when_not_required(self) -> None:
        service = FakeBacktestService([])
        output = io.StringIO()

        with contextlib.redirect_stdout(output):
            exit_code = run_backtest_once(service=service, instrument_id=3, limit=5, require_quality_gate=False)

        self.assertEqual(exit_code, 0)
        self.assertEqual(service.calls[0]["instrument_id"], 3)
        self.assertEqual(service.calls[0]["limit"], 5)
        self.assertIsNone(service.calls[0]["quality_gate"])
        self.assertIn("Backtest quality gate passed: False", output.getvalue())

    def test_run_backtest_once_blocks_failed_quality_gate_when_required(self) -> None:
        output = io.StringIO()

        with contextlib.redirect_stdout(output):
            exit_code = run_backtest_once(service=FakeBacktestService([]), require_quality_gate=True)

        self.assertEqual(exit_code, 2)
        self.assertIn("executed_sample_too_small", output.getvalue())

    def test_run_backtest_once_passes_when_required_quality_gate_is_healthy(self) -> None:
        outcomes = [_build_win_outcome(signal_id=index) for index in range(100)]
        output = io.StringIO()

        with contextlib.redirect_stdout(output):
            exit_code = run_backtest_once(service=FakeBacktestService(outcomes), require_quality_gate=True)

        self.assertEqual(exit_code, 0)
        self.assertIn("Backtest quality gate passed: True", output.getvalue())

    def test_run_backtest_once_outputs_json_success_summary(self) -> None:
        outcomes = [_build_win_outcome(signal_id=index) for index in range(100)]
        output = io.StringIO()

        with contextlib.redirect_stdout(output):
            exit_code = run_backtest_once(service=FakeBacktestService(outcomes), require_quality_gate=True, output_json=True)

        payload = json.loads(output.getvalue())
        self.assertEqual(exit_code, 0)
        self.assertTrue(payload["passed"])
        self.assertTrue(payload["quality_gate_required"])
        self.assertEqual(payload["backtest_run_id"], 99)
        self.assertEqual(payload["result_count"], 100)
        self.assertIsNone(payload["timeframe_set"])
        self.assertTrue(payload["quality_gate"]["passed"])
        self.assertEqual(payload["summary"]["executed_signals"], 100)

    def test_run_backtest_once_outputs_json_quality_failure(self) -> None:
        output = io.StringIO()

        with contextlib.redirect_stdout(output):
            exit_code = run_backtest_once(service=FakeBacktestService([]), require_quality_gate=True, output_json=True)

        payload = json.loads(output.getvalue())
        self.assertEqual(exit_code, 2)
        self.assertFalse(payload["passed"])
        self.assertFalse(payload["quality_gate"]["passed"])
        self.assertIn("executed_sample_too_small", payload["quality_gate"]["reasons"])

    def test_run_backtest_once_passes_replay_mode_and_config(self) -> None:
        service = FakeBacktestService([])
        output = io.StringIO()
        replay_config = build_replay_config_from_env(
            {
                "BACKTEST_REPLAY_LEFT_BARS": "1",
                "BACKTEST_REPLAY_RIGHT_BARS": "1",
            }
        )

        with contextlib.redirect_stdout(output):
            exit_code = run_backtest_once(
                service=service,
                backtest_mode="replay_no_lookahead",
                replay_config=replay_config,
            )

        self.assertEqual(exit_code, 0)
        self.assertEqual(service.calls[0]["mode"], "replay_no_lookahead")
        self.assertEqual(service.calls[0]["replay_config"].left_bars, 1)
        self.assertEqual(service.calls[0]["replay_config"].right_bars, 1)

    def test_run_backtest_once_passes_plan_replay_dimension(self) -> None:
        service = FakeBacktestService([])
        output = io.StringIO()

        with contextlib.redirect_stdout(output):
            exit_code = run_backtest_once(
                service=service,
                subject_type="plan_replay",
                trading_plan_id=77,
                candidate_model_code="OSOK",
                session_codes=["LONDON"],
            )

        self.assertEqual(exit_code, 0)
        self.assertEqual(service.calls[0]["subject_type"], "plan_replay")
        self.assertEqual(service.calls[0]["trading_plan_id"], 77)
        self.assertEqual(service.calls[0]["candidate_model_code"], "OSOK")
        self.assertEqual(service.calls[0]["session_codes"], ["LONDON"])

    def test_main_reports_database_unavailable(self) -> None:
        output = io.StringIO()

        with patch("scripts.run_backtest.BacktestService.run_backtest", side_effect=OperationalError("stmt", {}, Exception())), contextlib.redirect_stdout(output):
            exit_code = run_backtest.main()

        self.assertEqual(exit_code, 2)
        self.assertIn("Database unavailable for backtest sample: OperationalError", output.getvalue())

    def test_main_reports_database_unavailable_as_json(self) -> None:
        output = io.StringIO()

        with patch("scripts.run_backtest.BacktestService.run_backtest", side_effect=OperationalError("stmt", {}, Exception())), contextlib.redirect_stdout(output):
            exit_code = run_backtest.main(env={"BACKTEST_OUTPUT_JSON": "1"})

        payload = json.loads(output.getvalue())
        self.assertEqual(exit_code, 2)
        self.assertFalse(payload["passed"])
        self.assertEqual(payload["error_type"], "OperationalError")
        self.assertIsNone(payload["quality_gate"])


class FakeBacktestService:
    def __init__(self, outcomes: list[BacktestOutcome]) -> None:
        self.outcomes = outcomes
        self.calls = []

    def run_backtest(self, **kwargs):
        self.calls.append(kwargs)
        return 99, self.outcomes


def _build_win_outcome(signal_id: int) -> BacktestOutcome:
    return BacktestOutcome(
        signal_id=signal_id,
        outcome="win",
        mfe=2.0,
        mae=0.0,
        tp1_hit=True,
        tp2_hit=True,
        invalidated_before_entry=False,
        error_tags=[],
        meta={
            "signal_side": "buy",
            "session_codes": ["LONDON"],
            "weekday": "Wednesday",
            "mfe_r": 2.0,
            "mae_r": 0.0,
            "cost_r": 0.0,
            "r_multiple": 2.0,
        },
    )


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