from types import SimpleNamespace

from backend.app.ai_parser import (
    _estimate_text_width,
    _estimate_text_width_from_text_matrix,
    _page_horizontal_offset,
    _text_rect_from_matrix,
)


def test_text_rect_from_matrix_uses_rendered_height_and_baseline() -> None:
    font_size_pt, x0_pt, top_pt, x1_pt, bottom_pt = _text_rect_from_matrix(
        "食品名称： 天问礼品粽 （粽子/草木灰咸鸭蛋）",
        [19.3618, 0.0, 0.0, 21.0, 435.9155, 629.3184],
        942.06,
        None,
    )

    assert font_size_pt == 21.0
    assert x0_pt == 435.92
    assert top_pt == 291.74
    assert bottom_pt == 312.74
    assert x1_pt > x0_pt


def test_text_rect_from_matrix_handles_small_text_without_collapsing_height() -> None:
    font_size_pt, x0_pt, top_pt, x1_pt, bottom_pt = _text_rect_from_matrix(
        "儿童青少年应避免过量摄入盐油糖。",
        [4.3157, 0.0, 0.0, 8.0, 680.7383741, 516.1778],
        942.06,
        None,
    )

    assert font_size_pt == 8.0
    assert x0_pt == 680.74
    assert top_pt == 417.88
    assert bottom_pt == 425.88
    assert x1_pt > x0_pt


def test_text_rect_from_matrix_applies_page_horizontal_offset() -> None:
    font_size_pt, x0_pt, top_pt, x1_pt, bottom_pt = _text_rect_from_matrix(
        "材质：",
        [7.0652, 0.0, 0.0, 12.36, 190.6111, 873.561],
        942.06,
        None,
        24.21,
    )

    assert font_size_pt == 12.36
    assert x0_pt == 166.4
    assert top_pt == 56.14
    assert bottom_pt == 68.5
    assert x1_pt > x0_pt


def test_page_horizontal_offset_uses_artbox_left_inset() -> None:
    page = SimpleNamespace(
        artbox=SimpleNamespace(left=24.2137, width=1314.7563),
        cropbox=SimpleNamespace(width=1363.4),
    )

    assert _page_horizontal_offset(page) == 24.2137


def test_text_matrix_width_is_tighter_than_fallback_for_food_name() -> None:
    text = "食品名称： 天问礼品粽 （粽子/草木灰咸鸭蛋）"
    reference_width = 374.51

    fallback_width = round(_estimate_text_width(text, 21.0), 2)
    matrix_width = round(_estimate_text_width_from_text_matrix(text, 19.3618) or 0.0, 2)

    assert matrix_width > 0
    assert abs(matrix_width - reference_width) < abs(fallback_width - reference_width)


def test_text_matrix_width_is_tighter_than_fallback_for_small_heading() -> None:
    text = "营养成分表"
    reference_width = 21.75

    fallback_width = round(_estimate_text_width(text, 8.0), 2)
    matrix_width = round(_estimate_text_width_from_text_matrix(text, 4.3157) or 0.0, 2)

    assert matrix_width > 0
    assert abs(matrix_width - reference_width) <= abs(fallback_width - reference_width)