"""Tests for the RNG protocol, SeededRng, and ScriptedRng."""

import pytest

from pf1e_simulator.rng import RngExhaustedError, ScriptedRng, SeededRng


class TestSeededRngRollDie:
    """Given: a SeededRng with a fixed seed
    When: roll_die is called
    Then: returns values in 1..=sides deterministically."""

    def test_roll_die_returns_in_range(self) -> None:
        rng = SeededRng(42)
        for _ in range(100):
            result = rng.roll_die(6)
            assert 1 <= result <= 6

    def test_roll_die_d20_in_range(self) -> None:
        rng = SeededRng(42)
        for _ in range(100):
            result = rng.d20()
            assert 1 <= result <= 20

    def test_d20_is_roll_die_20(self) -> None:
        rng1 = SeededRng(123)
        rng2 = SeededRng(123)
        assert rng1.d20() == rng2.roll_die(20)


class TestSeededRngChoiceIndex:
    """Given: a SeededRng
    When: choice_index(n) is called
    Then: returns values in 0..n-1."""

    def test_choice_index_in_range(self) -> None:
        rng = SeededRng(42)
        for _ in range(100):
            result = rng.choice_index(5)
            assert 0 <= result <= 4


class TestSeededRngReproducibility:
    """Given: two SeededRng instances with the same seed
    When: each produces 1000 rolls
    Then: the streams are identical."""

    def test_identical_d20_streams(self) -> None:
        rng1 = SeededRng(42)
        rng2 = SeededRng(42)
        rolls1 = [rng1.d20() for _ in range(1000)]
        rolls2 = [rng2.d20() for _ in range(1000)]
        assert rolls1 == rolls2

    def test_identical_choice_index_streams(self) -> None:
        rng1 = SeededRng(42)
        rng2 = SeededRng(42)
        idx1 = [rng1.choice_index(8) for _ in range(1000)]
        idx2 = [rng2.choice_index(8) for _ in range(1000)]
        assert idx1 == idx2

    def test_different_seeds_produce_different_streams(self) -> None:
        rng1 = SeededRng(1)
        rng2 = SeededRng(2)
        rolls1 = [rng1.d20() for _ in range(100)]
        rolls2 = [rng2.d20() for _ in range(100)]
        assert rolls1 != rolls2


class TestScriptedRng:
    """Given: a ScriptedRng with a queue of ints
    When: roll_die / choice_index is called
    Then: returns queued values in order."""

    def test_roll_die_returns_queued_values(self) -> None:
        rng = ScriptedRng([3, 1, 4, 1, 5])
        assert rng.roll_die(6) == 3
        assert rng.roll_die(6) == 1
        assert rng.roll_die(6) == 4

    def test_d20_returns_queued_values(self) -> None:
        rng = ScriptedRng([20, 1, 13])
        assert rng.d20() == 20
        assert rng.d20() == 1
        assert rng.d20() == 13

    def test_choice_index_returns_queued_values(self) -> None:
        rng = ScriptedRng([0, 2, 1])
        assert rng.choice_index(5) == 0
        assert rng.choice_index(5) == 2
        assert rng.choice_index(5) == 1

    def test_raises_on_exhaustion_roll_die(self) -> None:
        rng = ScriptedRng([5])
        rng.roll_die(6)
        with pytest.raises(RngExhaustedError):
            rng.roll_die(6)

    def test_raises_on_exhaustion_d20(self) -> None:
        rng = ScriptedRng([10])
        rng.d20()
        with pytest.raises(RngExhaustedError):
            rng.d20()

    def test_raises_on_exhaustion_choice_index(self) -> None:
        rng = ScriptedRng([0])
        rng.choice_index(3)
        with pytest.raises(RngExhaustedError):
            rng.choice_index(3)

    def test_exhaustion_error_carries_message(self) -> None:
        rng = ScriptedRng([1])
        rng.roll_die(6)
        with pytest.raises(RngExhaustedError, match="exhausted"):
            rng.roll_die(6)