from __future__ import annotations

import re
import unittest
from pathlib import Path


ROOT = Path(__file__).resolve().parents[1]
DOCS = ROOT / "docs"
MARKDOWN_LINK = re.compile(
    r"!?\[[^\n]*?\]\((?P<destination><[^>]+>|[^)\s]+)"
)


class DocumentationStructureTests(unittest.TestCase):
    def test_documentation_root_has_one_human_entry_point(self) -> None:
        self.assertEqual(
            [path.name for path in sorted(DOCS.glob("*.md"))],
            ["README.md"],
        )

    def test_documentation_front_doors_exist(self) -> None:
        expected = (
            DOCS / "strategy" / "PLATFORM_CORE_IDEAS.md",
            DOCS / "strategy" / "ROADMAP.md",
            DOCS / "strategy" / "STRATEGY_STATUS.md",
            DOCS / "strategy" / "REFERENCE_JOURNEY_PROGRAM.md",
        )
        self.assertFalse([path for path in expected if not path.is_file()])

    def test_local_markdown_links_resolve(self) -> None:
        broken: list[str] = []
        sources = [ROOT / "README.md", *sorted(DOCS.rglob("*.md"))]
        for source in sources:
            for line_number, line in enumerate(
                source.read_text(encoding="utf-8").splitlines(),
                start=1,
            ):
                for match in MARKDOWN_LINK.finditer(line):
                    destination = match.group("destination")
                    if destination.startswith("<") and destination.endswith(">"):
                        destination = destination[1:-1]
                    path_text = destination.split("#", 1)[0]
                    if (
                        not path_text
                        or path_text.startswith(("/", "mailto:", "data:"))
                        or "://" in path_text
                    ):
                        continue
                    target = (source.parent / path_text).resolve()
                    if not target.is_relative_to(ROOT):
                        continue
                    if not target.exists():
                        broken.append(
                            f"{source.relative_to(ROOT)}:{line_number}: {destination}"
                        )
        self.assertEqual(broken, [])


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