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 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)


@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()
        metadata = post.metadata

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

        tags = parse_tags(post.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(),
        )