import sys
import pathlib
sys.path.insert(0, str(pathlib.Path(__file__).resolve().parent.parent))

import os
import xml.etree.ElementTree as ET

import pytest

from enhanced_mcm_generator import EnhancedMCMGenerator


def _canonicalize_xml(path: str) -> bytes:
    """Return a canonicalised representation of an L5X / XML file.

    The function removes volatile attributes (e.g. ExportDate) and sorts
    attributes of every element so the resulting byte string is stable
    across Python runs and operating systems.
    """
    tree = ET.parse(path)
    root = tree.getroot()

    # Remove volatile attributes that change on every export (present on many elements)
    for elem in root.iter():
        elem.attrib.pop("ExportDate", None)

    # Recursively sort attributes to obtain a deterministic ordering
    def _sort_attrs(elem: ET.Element):
        if elem.attrib:
            # Convert to list with sorted items to keep ElementTree stable
            sorted_items = sorted(elem.attrib.items())
            elem.attrib.clear()
            elem.attrib.update(sorted_items)
        for child in elem:
            _sort_attrs(child)

    _sort_attrs(root)

    # Normalise text nodes: strip leading/trailing whitespace so that
    # cosmetic indentation inside <Comment> elements does not cause false
    # differences.
    for elem in root.iter():
        if elem.text is not None:
            elem.text = elem.text.strip()

    # ElementTree does not guarantee attribute ordering when converting to
    # string, but because we have manually re-inserted sorted attributes we
    # get a deterministic output here.
    return ET.tostring(root, encoding="utf-8")


@pytest.mark.regression
def test_generated_project_matches_golden(tmp_path):
    """Generate the project and compare it against the golden reference.

    If this test fails, a refactor has changed the *semantic* XML output.
    Check the diff to decide whether the change is intended or not.
    """
    project_name = "MCM04_Chute_Load"

    # 1. Run the generator to build a fresh project under the temporary dir
    generator = EnhancedMCMGenerator(project_name, excel_file="Data.xlsx")
    assert generator.load_and_process_data(), "Failed to load/process Excel data"

    output_path = generator.generate_complete_project()

    # 2. Compare with the golden file
    golden_path = os.path.join(
        "generated_projects", "MCM04_Chute_Load_To_Compare_Against.L5X"
    )
    assert os.path.exists(golden_path), "Golden file is missing"

    assert _canonicalize_xml(output_path) == _canonicalize_xml(
        golden_path
    ), "Generated project differs from golden reference"