from __future__ import annotations

import importlib.util
import json
import os
import tempfile
import unittest
from pathlib import Path

ROOT = Path(__file__).resolve().parents[2]
SCRIPT = ROOT / "scripts" / "verify-project-layout.py"

spec = importlib.util.spec_from_file_location("verify_project_layout", SCRIPT)
layout = importlib.util.module_from_spec(spec)
spec.loader.exec_module(layout)


def _section(line: int, level: int, title: str, start: int, end: int, text: str) -> dict:
    return {
        "heading": {"line": line, "level": level, "text": title},
        "start_line": start,
        "end_line": end,
        "text": text,
    }


class TechVizContextFallbackTest(unittest.TestCase):
    def _check(self, document: str, context: dict) -> bool | None:
        with tempfile.TemporaryDirectory() as tmp:
            root = Path(tmp)
            doc = root / "document.md"
            ctx = root / "context.json"
            doc.write_text(document, encoding="utf-8")
            ctx.write_text(json.dumps(context, ensure_ascii=False), encoding="utf-8")
            return layout._context_snapshot_matches(str(doc), str(ctx))

    def test_parent_predecessor_is_only_the_preamble_before_current_child(self):
        document = "\n".join([
            "# Root",
            "root",
            "## Parent",
            "preamble",
            "### Current",
            "current",
            "### Next",
            "next",
            "## Tail",
            "tail",
        ])
        context = {
            "anchor": {"kind": "heading", "value": "Current", "line": 5},
            "previous_section": _section(
                3, 2, "Parent", 3, 4, "## Parent\npreamble"
            ),
            "current_section": _section(
                5, 3, "Current", 5, 6, "### Current\ncurrent"
            ),
            "next_section": _section(
                7, 3, "Next", 7, 8, "### Next\nnext"
            ),
        }
        self.assertTrue(self._check(document, context))

        changed = document.replace("preamble", "changed preamble")
        self.assertFalse(self._check(changed, context))

    def test_fenced_hash_lines_do_not_end_neighbor_section(self):
        document = "\n".join([
            "# Root",
            "## Current",
            "current",
            "## Data",
            "intro",
            "~~~text",
            "# not a heading",
            "## also not a heading",
            "~~~",
            "tail",
            "## End",
            "end",
        ])
        context = {
            "anchor": {"kind": "heading", "value": "Current", "line": 2},
            "previous_section": _section(
                1, 1, "Root", 1, 1, "# Root"
            ),
            "current_section": _section(
                2, 2, "Current", 2, 3, "## Current\ncurrent"
            ),
            "next_section": _section(
                4, 2, "Data", 4, 10,
                "## Data\nintro\n~~~text\n# not a heading\n"
                "## also not a heading\n~~~\ntail",
            ),
        }
        self.assertTrue(self._check(document, context))

    def test_legacy_context_without_anchor_uses_current_heading(self):
        document = "\n".join([
            "# Root",
            "## Previous",
            "previous",
            "## Current",
            "current",
            "## Next",
            "next",
        ])
        context = {
            "previous_section": {
                "heading": {"text": "Previous"},
                "text": "## Previous\nprevious",
            },
            "current_section": {
                "heading": {"text": "Current"},
                "text": "## Current\ncurrent",
            },
            "next_section": {
                "heading": {"text": "Next"},
                "text": "## Next\nnext",
            },
        }
        self.assertTrue(self._check(document, context))

    def test_keycloak_session_store_seven_fresh_contexts_match_without_techviz(self):
        ids = [
            "a1-transport-vs-discovery",
            "d2-upgrade-direction",
            "lab-topology",
            "measurement-control",
            "observation-points",
            "open-questions-answered",
            "wrong-predictions",
        ]
        document = ROOT / "docs" / "keycloak-session-store" / "final" / "document.md"
        base = ROOT / "docs" / "keycloak-session-store" / "final" / ".techviz"
        for diagram_id in ids:
            with self.subTest(diagram_id=diagram_id):
                context = base / diagram_id / "context.json"
                self.assertTrue(
                    layout._context_snapshot_matches(str(document), str(context))
                )


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