"""Tests for textgrid color packing (no GPU required)."""

from textgrid._pack_style import pack_style_colors, _pack_one, _xterm


def test_pack_red():
    """(255, 0, 0) → 0xFF000000 (R in bits 31-24)"""
    from termstr import CharStyle
    result = pack_style_colors((CharStyle(fg_color=(255, 0, 0)),))
    assert result[0] == 0xFF000000


def test_pack_green():
    """(0, 255, 0) → 0x00FF0000 (G in bits 23-16)"""
    from termstr import CharStyle
    result = pack_style_colors((CharStyle(fg_color=(0, 255, 0)),))
    assert result[0] == 0x00FF0000


def test_pack_blue():
    """(0, 0, 255) → 0x0000FF00 (B in bits 15-8)"""
    from termstr import CharStyle
    result = pack_style_colors((CharStyle(fg_color=(0, 0, 255)),))
    assert result[0] == 0x0000FF00


def test_pack_black():
    """(0, 0, 0) → 0x00000000"""
    from termstr import CharStyle
    result = pack_style_colors((CharStyle(fg_color=(0, 0, 0)),))
    assert result[0] == 0x00000000


def test_pack_white():
    """(255, 255, 255) → 0xFFFFFF00"""
    from termstr import CharStyle
    result = pack_style_colors((CharStyle(fg_color=(255, 255, 255)),))
    assert result[0] == 0xFFFFFF00


def test_pack_fg_and_bg():
    """fg and bg are interleaved in the output array"""
    from termstr import CharStyle
    result = pack_style_colors((CharStyle(fg_color=(255, 0, 0), bg_color=(0, 0, 255)),))
    assert result[0] == 0xFF000000, "fg should be first"
    assert result[1] == 0x0000FF00, "bg should be second"
    assert result[2] == 0, "attr should be 0 for default style"


def test_pack_xterm_index_9():
    """xterm index 9 is bright red = (255, 0, 0)"""
    from termstr import CharStyle
    result = pack_style_colors((CharStyle(fg_color=9),))
    expected = pack_style_colors((CharStyle(fg_color=(255, 0, 0)),))
    assert result[0] == expected[0], "index 9 should match (255, 0, 0)"


def test_xterm_table_index_0():
    """xterm index 0 is (0, 0, 0)"""
    assert _xterm[0] == (0, 0, 0)


def test_xterm_table_index_1():
    """xterm index 1 is (205, 0, 0)"""
    assert _xterm[1] == (205, 0, 0)


def test_xterm_table_index_15():
    """xterm index 15 is (255, 255, 255)"""
    assert _xterm[15] == (255, 255, 255)


def test_xterm_table_index_16():
    """xterm index 16 is (0, 0, 0) — start of color cube"""
    assert _xterm[16] == (0, 0, 0)


def test_xterm_table_index_231():
    """xterm index 231 is (255, 255, 255) — end of color cube"""
    assert _xterm[231] == (255, 255, 255)


def test_xterm_table_index_232():
    """xterm index 232 is (8, 8, 8) — start of gray ramp"""
    assert _xterm[232] == (8, 8, 8)


def test_xterm_table_index_255():
    """xterm index 255 is (238, 238, 238) — end of gray ramp"""
    assert _xterm[255] == (238, 238, 238)


def test_identity_fast_path_matches_slow_path():
    """all(s is first) fast path produces same output as per-element iteration"""
    from termstr import CharStyle
    style = CharStyle(fg_color=(255, 80, 80), bg_color=(20, 40, 60))
    styles = tuple([style] * 100)
    # The identity check will trigger for n > 1
    result = pack_style_colors(styles)
    # Length: 100 chars * 3 values (fg, bg, attr) = 300
    assert len(result) == 300
    # Every triplet should be identical
    for i in range(0, 300, 3):
        assert result[i] == result[0], f"fg differs at char {i//3}"
        assert result[i + 1] == result[1], f"bg differs at char {i//3}"
        assert result[i + 2] == result[2], f"attr differs at char {i//3}"


def test_mixed_styles_are_all_different():
    """Each char has different colors — no identity optimization triggered"""
    from termstr import CharStyle
    styles = tuple([
        CharStyle(fg_color=(255, 0, 0)),
        CharStyle(fg_color=(0, 255, 0)),
        CharStyle(fg_color=(0, 0, 255)),
    ])
    result = pack_style_colors(styles)
    assert len(result) == 9
    assert result[0] != result[3], "red != green"
    assert result[0] != result[6], "red != blue"
    assert result[3] != result[6], "green != blue"


def test_output_length():
    """N chars produces 3N output values"""
    from termstr import CharStyle
    for n in [1, 5, 100]:
        styles = tuple([CharStyle(fg_color=(255, 0, 0))] * n)
        result = pack_style_colors(styles)
        assert len(result) == 3 * n, f"expected {3*n}, got {len(result)}"


def test_xterm_pack_matches_rgb():
    """Packing xterm index should produce same u32 as direct RGB"""
    from termstr import CharStyle
    for idx in [1, 9, 16, 100, 200, 255]:
        r, g, b = _xterm[idx]
        xterm_result = pack_style_colors((CharStyle(fg_color=idx),))
        rgb_result = pack_style_colors((CharStyle(fg_color=(r, g, b)),))
        assert xterm_result[0] == rgb_result[0], \
            f"index {idx} = ({r},{g},{b}) didn't match direct RGB"


def test_attr_encoding():
    """bold/italic flags encoded in attr byte"""
    from termstr import CharStyle
    r = pack_style_colors((CharStyle(fg_color=(255, 0, 0)),))
    assert r[2] == 0, "default: no bold, no italic"

    r = pack_style_colors((CharStyle(fg_color=(255, 0, 0)).bold(),))
    assert r[2] & 1, "bold bit set"

    r = pack_style_colors((CharStyle(fg_color=(255, 0, 0)).italic(),))
    assert r[2] & 2, "italic bit set"

    r = pack_style_colors((CharStyle(fg_color=(255, 0, 0)).bold().italic(),))
    assert (r[2] & 3) == 3, "both bold and italic bits set"

    r = pack_style_colors((CharStyle(fg_color=(255, 0, 0)).underline(),))
    assert r[2] & 4, "underline bit set"

    r = pack_style_colors((CharStyle(fg_color=(255, 0, 0)).bold().italic().underline(),))
    assert (r[2] & 7) == 7, "bold, italic, and underline bits set"