"""Unit tests for LanderCliEnv."""
from pathlib import Path

import numpy as np
import pytest
from gymnasium.utils.env_checker import check_env

# Add parent dir to sys.path so we can import lander_cli_env
import sys
sys.path.insert(0, str(Path(__file__).resolve().parent.parent))

from lander_cli_env import LanderCliEnv


REPO_ROOT = Path(__file__).resolve().parents[2]
CLI_BINARY = REPO_ROOT / "publish" / "GameCli" / "GameCli"


@pytest.fixture(scope="module")
def cli_binary_exists():
    if not CLI_BINARY.exists():
        pytest.skip(f"CLI binary not found at {CLI_BINARY} — run `dotnet publish GameCli -c Release -o publish/GameCli`")
    return CLI_BINARY


def test_env_opens_and_closes(cli_binary_exists):
    env = LanderCliEnv(cli_binary=str(cli_binary_exists))
    env.close()  # should not raise


def test_observation_space_is_seven_dim(cli_binary_exists):
    env = LanderCliEnv(cli_binary=str(cli_binary_exists))
    try:
        assert env.observation_space.shape == (7,)
    finally:
        env.close()


def test_action_space_is_discrete_four(cli_binary_exists):
    env = LanderCliEnv(cli_binary=str(cli_binary_exists))
    try:
        assert env.action_space.n == 4
    finally:
        env.close()


def test_reset_returns_seven_dim_observation(cli_binary_exists):
    env = LanderCliEnv(cli_binary=str(cli_binary_exists))
    try:
        obs, info = env.reset(seed=42)
        assert isinstance(obs, np.ndarray)
        assert obs.shape == (7,)
        assert obs.dtype == np.float32
    finally:
        env.close()


def test_step_advances_and_returns_five_tuple(cli_binary_exists):
    env = LanderCliEnv(cli_binary=str(cli_binary_exists))
    try:
        env.reset(seed=0)
        obs, reward, terminated, truncated, info = env.step(0)  # noop
        assert obs.shape == (7,)
        assert isinstance(reward, float)
        assert terminated is False  # never terminates
        assert isinstance(truncated, bool)
    finally:
        env.close()


def test_reset_randomizes_target_across_episodes(cli_binary_exists):
    env = LanderCliEnv(cli_binary=str(cli_binary_exists))
    try:
        # Two resets with different seeds should generally give different targets.
        env.reset(seed=1)
        target1 = env._target
        env.reset(seed=2)
        target2 = env._target
        assert target1 != target2
    finally:
        env.close()


def test_truncation_at_max_steps(cli_binary_exists):
    env = LanderCliEnv(cli_binary=str(cli_binary_exists), max_episode_steps=5)
    try:
        env.reset(seed=0)
        truncated = False
        for _ in range(5):
            _, _, _, truncated, _ = env.step(0)
        assert truncated is True
    finally:
        env.close()


def test_check_env_passes(cli_binary_exists):
    """Gymnasium's own env sanity checker — spaces, dtypes, reset/step contract."""
    env = LanderCliEnv(cli_binary=str(cli_binary_exists), max_episode_steps=50)
    try:
        # skip_render_check because we don't implement rendering
        check_env(env.unwrapped, skip_render_check=True)
    finally:
        env.close()