"""End-to-end orientation-detection tests against synthetic text pages.

Skipped automatically if the tesseract binary isn't installed.
"""

from __future__ import annotations

import shutil

import cv2
import numpy as np
import pytest
from PIL import Image, ImageDraw, ImageFont

from paperpod.vision.orient import apply_rotation, auto_rotate

pytestmark = pytest.mark.skipif(
    shutil.which("tesseract") is None, reason="tesseract binary not installed"
)

_FONT_CANDIDATES = [
    "/System/Library/Fonts/Helvetica.ttc",
    "/System/Library/Fonts/Supplemental/Arial.ttf",
]


def _font(size: int) -> ImageFont.FreeTypeFont | ImageFont.ImageFont:
    for path in _FONT_CANDIDATES:
        try:
            return ImageFont.truetype(path, size)
        except OSError:
            continue
    return ImageFont.load_default()


def _text_page() -> np.ndarray:
    """A tall white page with a few lines of real words (upright, 0 degrees).

    Rendered with a real TrueType font (not cv2.putText's blocky stroke
    font), which produces normal glyph shapes; cv2.putText text fragments
    into dozens of spurious single-character "words" when rotated sideways,
    which isn't representative of real documents/photos.
    """
    img = Image.new("RGB", (400, 600), (255, 255, 255))
    draw = ImageDraw.Draw(img)
    font = _font(22)
    lines = [
        "INVOICE FROM ACME CORP",
        "Date: January 5, 2024",
        "Description of services rendered",
        "Thank you for your business",
        "Please remit payment within 30 days",
    ]
    for i, line in enumerate(lines):
        draw.text((20, 80 + i * 60), line, fill=(0, 0, 0), font=font)
    return cv2.cvtColor(np.array(img), cv2.COLOR_RGB2BGR)


@pytest.mark.parametrize("applied_rotation", [0, 90, 180, 270])
def test_auto_rotate_corrects_known_rotation(applied_rotation):
    """Rotating upright text by N clockwise needs (360-N) clockwise to undo."""
    upright = _text_page()
    rotated_input = apply_rotation(upright, applied_rotation)
    corrected, result = auto_rotate(rotated_input)
    assert result.rotation == (360 - applied_rotation) % 360
    assert corrected.shape == upright.shape


def test_apply_rotation_identity_at_zero():
    page = _text_page()
    assert np.array_equal(apply_rotation(page, 0), page)


def test_apply_rotation_180_is_involutive():
    page = _text_page()
    twice = apply_rotation(apply_rotation(page, 180), 180)
    assert np.array_equal(twice, page)