entity_parser.py

"""Parser for markdown files into Entity objects.

Uses markdown-it with plugins to parse structured data from markdown content.
"""

from dataclasses import dataclass, field
from datetime import date, datetime
from pathlib import Path
from typing import Any, Optional

import dateparser
import frontmatter
import yaml
from loguru import logger
from markdown_it import MarkdownIt

from basic_memory.markdown.plugins import observation_plugin, relation_plugin
from basic_memory.markdown.schemas import (
    EntityFrontmatter,
    EntityMarkdown,
    Observation,
    Relation,
)
from basic_memory.utils import parse_tags

md = MarkdownIt().use(observation_plugin).use(relation_plugin)


def normalize_frontmatter_value(value: Any) -> Any:
    """Normalize frontmatter values to safe types for processing.

    PyYAML automatically converts various string-like values into native Python types:
    - Date strings ("2025-10-24") → datetime.date objects
    - Numbers ("1.0") → int or float
    - Booleans ("true") → bool
    - Lists → list objects

    This can cause AttributeError when code expects strings and calls string methods
    like .strip() on these values (see GitHub issue #236).

    This function normalizes all frontmatter values to safe types:
    - Dates/datetimes → ISO format strings
    - Numbers (int/float) → strings
    - Booleans → strings ("True"/"False")
    - Lists → preserved as lists, but items are recursively normalized
    - Dicts → preserved as dicts, but values are recursively normalized
    - Strings → kept as-is
    - None → kept as None

    Args:
        value: The frontmatter value to normalize

    Returns:
        The normalized value safe for string operations

    Example:
        >>> normalize_frontmatter_value(datetime.date(2025, 10, 24))
        '2025-10-24'
        >>> normalize_frontmatter_value([datetime.date(2025, 10, 24), "tag", 123])
        ['2025-10-24', 'tag', '123']
        >>> normalize_frontmatter_value(True)
        'True'
    """
    # Convert date/datetime objects to ISO format strings
    if isinstance(value, datetime):
        return value.isoformat()
    if isinstance(value, date):
        return value.isoformat()

    # Convert boolean to string (must come before int check since bool is subclass of int)
    if isinstance(value, bool):
        return str(value)

    # Convert numbers to strings
    if isinstance(value, (int, float)):
        return str(value)

    # Recursively process lists (preserve as list, normalize items)
    if isinstance(value, list):
        return [normalize_frontmatter_value(item) for item in value]

    # Recursively process dicts (preserve as dict, normalize values)
    if isinstance(value, dict):
        return {key: normalize_frontmatter_value(val) for key, val in value.items()}

    # Keep strings and None as-is
    return value


def normalize_frontmatter_metadata(metadata: dict) -> dict:
    """Normalize all values in frontmatter metadata dict.

    Converts date/datetime objects to ISO format strings to prevent
    AttributeError when code expects strings (GitHub issue #236).

    Args:
        metadata: The frontmatter metadata dictionary

    Returns:
        A new dictionary with all values normalized
    """
    return {key: normalize_frontmatter_value(value) for key, value in metadata.items()}


@dataclass
class EntityContent:
    content: str
    observations: list[Observation] = field(default_factory=list)
    relations: list[Relation] = field(default_factory=list)


def parse(content: str) -> EntityContent:
    """Parse markdown content into EntityMarkdown."""

    # Parse content for observations and relations using markdown-it
    observations = []
    relations = []

    if content:
        for token in md.parse(content):
            # check for observations and relations
            if token.meta:
                if "observation" in token.meta:
                    obs = token.meta["observation"]
                    observation = Observation.model_validate(obs)
                    observations.append(observation)
                if "relations" in token.meta:
                    rels = token.meta["relations"]
                    relations.extend([Relation.model_validate(r) for r in rels])

    return EntityContent(
        content=content,
        observations=observations,
        relations=relations,
    )


# def parse_tags(tags: Any) -> list[str]:
#     """Parse tags into list of strings."""
#     if isinstance(tags, (list, tuple)):
#         return [str(t).strip() for t in tags if str(t).strip()]
#     return [t.strip() for t in tags.split(",") if t.strip()]


class EntityParser:
    """Parser for markdown files into Entity objects."""

    def __init__(self, base_path: Path):
        """Initialize parser with base path for relative permalink generation."""
        self.base_path = base_path.resolve()

    def parse_date(self, value: Any) -> Optional[datetime]:
        """Parse date strings using dateparser for maximum flexibility.

        Supports human friendly formats like:
        - 2024-01-15
        - Jan 15, 2024
        - 2024-01-15 10:00 AM
        - yesterday
        - 2 days ago
        """
        if isinstance(value, datetime):
            return value
        if isinstance(value, str):
            parsed = dateparser.parse(value)
            if parsed:
                return parsed
        return None

    async def parse_file(self, path: Path | str) -> EntityMarkdown:
        """Parse markdown file into EntityMarkdown."""

        # Check if the path is already absolute
        if (
            isinstance(path, Path)
            and path.is_absolute()
            or (isinstance(path, str) and Path(path).is_absolute())
        ):
            absolute_path = Path(path)
        else:
            absolute_path = self.get_file_path(path)

        # Parse frontmatter and content using python-frontmatter
        file_content = absolute_path.read_text(encoding="utf-8")
        return await self.parse_file_content(absolute_path, file_content)

    def get_file_path(self, path):
        """Get absolute path for a file using the base path for the project."""
        return self.base_path / path

    async def parse_file_content(self, absolute_path, file_content):
        # Parse frontmatter with proper error handling for malformed YAML (issue #185)
        try:
            post = frontmatter.loads(file_content)
        except yaml.YAMLError as e:
            # Log the YAML parsing error with file context
            logger.warning(
                f"Failed to parse YAML frontmatter in {absolute_path}: {e}. "
                f"Treating file as plain markdown without frontmatter."
            )
            # Create a post with no frontmatter - treat entire content as markdown
            post = frontmatter.Post(file_content, metadata={})

        # Extract file stat info
        file_stats = absolute_path.stat()

        # Normalize frontmatter values to prevent AttributeError on date objects (issue #236)
        # PyYAML automatically converts date strings like "2025-10-24" to datetime.date objects
        # This normalization converts them back to ISO format strings to ensure compatibility
        # with code that expects string values
        metadata = normalize_frontmatter_metadata(post.metadata)

        # Ensure required fields have defaults (issue #184, #387)
        # Handle title - use default if missing, None/null, empty, or string "None"
        title = metadata.get("title")
        if not title or title == "None":
            metadata["title"] = absolute_path.stem
        else:
            metadata["title"] = title
        # Handle type - use default if missing OR explicitly set to None/null
        entity_type = metadata.get("type")
        metadata["type"] = entity_type if entity_type is not None else "note"

        tags = parse_tags(metadata.get("tags", []))  # pyright: ignore
        if tags:
            metadata["tags"] = tags

        # frontmatter - use metadata with defaults applied
        entity_frontmatter = EntityFrontmatter(
            metadata=metadata,
        )
        entity_content = parse(post.content)
        return EntityMarkdown(
            frontmatter=entity_frontmatter,
            content=post.content,
            observations=entity_content.observations,
            relations=entity_content.relations,
            created=datetime.fromtimestamp(file_stats.st_ctime).astimezone(),
            modified=datetime.fromtimestamp(file_stats.st_mtime).astimezone(),
        )