from __future__ import annotations

from pathlib import PurePosixPath
from typing import Any

import pytest
import yaml
from pydantic import ValidationError

from personal_mcp.registry.ingest.document import MarkdownDocument
from personal_mcp.registry.load import _parse_frontmatter
from personal_mcp.registry.models.common import _normalize_docs_path
from personal_mcp.registry.models.registry import DocsRegistry

pytestmark = pytest.mark.unit


def make_markdown_document(
    relpath: str,
    *,
    content: str = "# body\n",
    frontmatter: str | None = None,
) -> MarkdownDocument:
    """Builds a markdown ingest document with deterministic defaults."""
    return MarkdownDocument(
        relpath=PurePosixPath(relpath),
        content=content,
        frontmatter=frontmatter,
    )


def make_skill_frontmatter_payload(
    *,
    skill_id: str,
    name: str | None = None,
    version: str = "1.0.0",
    description: str = "demo skill",
    tags: tuple[str, ...] = ("testing",),
    capabilities: tuple[str, ...] | None = None,
    depends_on: tuple[str, ...] = (),
    references: dict[str, dict[str, Any]] | None = None,
) -> str:
    """Builds frontmatter payload YAML for skill conversion tests."""
    canonical_name = name or skill_id
    payload: dict[str, Any] = {
        "name": canonical_name,
        "description": description,
        "x-personal-mcp": {
            "id": skill_id,
            "version": version,
            "tags": list(tags),
            "capabilities": list(capabilities or (f"resource://skills/{canonical_name}/document",)),
            "depends_on": list(depends_on),
        },
    }
    if references is not None:
        payload["x-personal-mcp"]["references"] = references
    return yaml.safe_dump(payload, sort_keys=False)


def make_prompt_frontmatter_payload(
    *,
    prompt_id: str,
    name: str | None = None,
    version: str = "1.0.0",
    description: str = "demo prompt",
    tags: tuple[str, ...] = ("testing",),
    capabilities: tuple[str, ...] | None = None,
    arguments: dict[str, dict[str, Any]] | None = None,
) -> str:
    """Builds frontmatter payload YAML for prompt conversion tests."""
    canonical_name = name or prompt_id
    payload: dict[str, Any] = {
        "name": canonical_name,
        "description": description,
        "x-personal-mcp": {
            "id": prompt_id,
            "version": version,
            "tags": list(tags),
            "capabilities": list(capabilities or (f"resource://prompts/{canonical_name}/document",)),
            "arguments": arguments or {},
        },
    }
    return yaml.safe_dump(payload, sort_keys=False)


def as_markdown(frontmatter_yaml: str, *, body: str = "# body\n") -> str:
    """Wraps frontmatter YAML in markdown fence delimiters."""
    return f"---\n{frontmatter_yaml.strip()}\n---\n{body}"


def assert_model_is_frozen(instance: Any, *, attr: str, value: Any) -> None:
    """Asserts pydantic frozen model semantics."""
    with pytest.raises(ValidationError, match="Instance is frozen"):
        setattr(instance, attr, value)


class TestGate1LayoutValidation:
    """Gate 1: source layout and parse shape constraints."""

    def test_parse_frontmatter_requires_payload(self) -> None:
        """Ensures missing frontmatter fails before metadata validation."""
        with pytest.raises(ValueError, match="missing YAML frontmatter"):
            _parse_frontmatter(None, path=PurePosixPath("skills/alpha/SKILL.md"))

    def test_parse_frontmatter_requires_mapping(self) -> None:
        """Ensures non-object YAML payloads are rejected at parse time."""
        with pytest.raises(TypeError, match="frontmatter must parse to an object"):
            _parse_frontmatter("- one\n- two\n", path=PurePosixPath("skills/alpha/SKILL.md"))

    def test_parse_frontmatter_accepts_mapping(self) -> None:
        """Ensures valid mapping payload is returned for downstream validation."""
        parsed = _parse_frontmatter("name: alpha\n", path=PurePosixPath("skills/alpha/SKILL.md"))

        assert parsed == {"name": "alpha"}


class TestGate5ContractValidation:
    """Gate 5: canonical resource-path contract normalization."""

    def test_normalize_docs_path_keeps_posix_relative_paths(self) -> None:
        """Ensures docs paths remain normalized before registry publication."""
        assert _normalize_docs_path("skills/demo/SKILL.md") == "skills/demo/SKILL.md"

    def test_normalize_docs_path_rejects_parent_traversal(self) -> None:
        """Ensures traversal attempts fail contract validation."""
        with pytest.raises(ValueError, match="normalized docs-relative path"):
            _normalize_docs_path("../outside.md")


class TestGate6FreezeValidation:
    """Gate 6: immutable in-memory registry snapshot semantics."""

    def test_docs_registry_copies_mapping_inputs(self) -> None:
        """Ensures registry snapshots are isolated from caller-owned mapping mutations."""
        source_docs = {"index.md": "# index\n"}
        registry = DocsRegistry(
            skills_by_id={},
            skills_in_load_order=(),
            skills_summary_in_load_order=(),
            docs_markdown_by_path=source_docs,
            docs_markdown_path_index=("index.md",),
            tag_to_skill_ids={},
            capability_to_skill_ids={},
            prompts_by_id={},
            prompts_in_load_order=(),
            prompts_summary_in_load_order=(),
            tag_to_prompt_ids={},
        )

        source_docs["other.md"] = "# other\n"

        assert "other.md" not in registry.docs_markdown_by_path

    def test_docs_registry_instance_is_frozen(self) -> None:
        """Ensures frozen model prevents attribute reassignment."""
        registry = DocsRegistry(
            skills_by_id={},
            skills_in_load_order=(),
            skills_summary_in_load_order=(),
            docs_markdown_by_path={},
            docs_markdown_path_index=(),
            tag_to_skill_ids={},
            capability_to_skill_ids={},
            prompts_by_id={},
            prompts_in_load_order=(),
            prompts_summary_in_load_order=(),
            tag_to_prompt_ids={},
        )

        assert_model_is_frozen(registry, attr="docs_markdown_path_index", value=("index.md",))