#!/usr/bin/env python3
"""Synthetic regression tests for strict firmware-memory validation."""

import importlib.util
import json
import unittest


def load_analyzer_module():
    spec = importlib.util.spec_from_file_location("analyze_fw", "scripts/analyze-fw.py")
    assert spec is not None and spec.loader is not None
    module = importlib.util.module_from_spec(spec)
    spec.loader.exec_module(module)
    return module


ANALYZER = load_analyzer_module()
LAYOUT = [("FLASH", 0x08000000, 0x100), ("RAM", 0x20000000, 0x80)]


class FirmwareMemoryValidationTests(unittest.TestCase):
    def test_elf_layout_uses_alloc_flag_and_only_load_segments(self):
        document = [
            {
                "Sections": [
                    {
                        "Section": {
                            "Name": {"Name": ".text"},
                            "Size": 8,
                            "Address": 0x08000000,
                            "Flags": {"Flags": [{"Name": "SHF_ALLOC"}]},
                        }
                    },
                    {
                        "Section": {
                            "Name": {"Name": ".debug_info"},
                            "Size": 100,
                            "Address": 0,
                            "Flags": {"Flags": []},
                        }
                    },
                ],
                "ProgramHeaders": [
                    {
                        "ProgramHeader": {
                            "Type": {"Name": "PT_LOAD"},
                            "VirtualAddress": 0x08000000,
                            "PhysicalAddress": 0x08000000,
                            "FileSize": 8,
                            "MemSize": 8,
                        }
                    },
                    {
                        "ProgramHeader": {
                            "Type": {"Name": "PT_ARM_EXIDX"},
                            "VirtualAddress": 0,
                            "PhysicalAddress": 0,
                            "FileSize": 0,
                            "MemSize": 0,
                        }
                    },
                ],
            }
        ]

        sections, segments = ANALYZER.elf_layout(json.dumps(document))

        self.assertEqual(
            sections,
            [
                ANALYZER.Section(".text", 8, 0x08000000, True),
                ANALYZER.Section(".debug_info", 100, 0, False),
            ],
        )
        self.assertEqual(
            segments,
            [ANALYZER.LoadSegment(0x08000000, 0x08000000, 8, 8)],
        )

    def test_accepts_allocated_memory_and_ignores_debug_sections(self):
        sections = [
            ANALYZER.Section(".text", 0x80, 0x08000000, True),
            ANALYZER.Section(".bss", 0x40, 0x20000000, True),
            ANALYZER.Section(".debug_info", 0x1000, 0, False),
            ANALYZER.Section(".empty", 0, 0xDEADBEEF, True),
        ]
        segments = [
            ANALYZER.LoadSegment(0x08000000, 0x08000000, 0x80, 0x80),
            ANALYZER.LoadSegment(0x20000000, 0x20000000, 0, 0x40),
        ]

        self.assertEqual(ANALYZER.validation_errors(LAYOUT, sections, segments), [])

    def test_rejects_allocated_sections_outside_or_crossing_a_region(self):
        outside = [ANALYZER.Section(".text", 4, 0x08000200, True)]
        crossing = [ANALYZER.Section(".text", 2, 0x080000FF, True)]

        self.assertIn(
            "allocated section .text",
            ANALYZER.validation_errors(LAYOUT, outside, [])[0],
        )
        self.assertIn(
            "allocated section .text",
            ANALYZER.validation_errors(LAYOUT, crossing, [])[0],
        )

    def test_usage_counts_data_load_image_without_double_counting_text(self):
        sections = [
            ANALYZER.Section(".text", 0x40, 0x08000000, True),
            ANALYZER.Section(".data", 0x10, 0x20000000, True),
        ]
        segments = [
            ANALYZER.LoadSegment(0x08000000, 0x08000000, 0x40, 0x40),
            ANALYZER.LoadSegment(0x20000000, 0x08000040, 0x10, 0x10),
        ]

        self.assertEqual(
            ANALYZER.region_usage("FLASH", LAYOUT, sections, segments), 0x50
        )
        self.assertEqual(
            ANALYZER.region_usage("RAM", LAYOUT, sections, segments), 0x10
        )

    def test_rejects_loadable_virtual_and_physical_spans_outside_memory(self):
        segments = [
            ANALYZER.LoadSegment(0x09000000, 0x08000000, 4, 4),
            ANALYZER.LoadSegment(0x20000000, 0x09000000, 4, 4),
        ]

        errors = ANALYZER.validation_errors(LAYOUT, [], segments)
        self.assertTrue(any("virtual span" in error for error in errors))
        self.assertTrue(any("physical span" in error for error in errors))


if __name__ == "__main__":
    unittest.main()