"""Service for resolving markdown links to permalinks."""
from typing import Optional, Tuple
from loguru import logger
from basic_memory.models import Entity
from basic_memory.repository.entity_repository import EntityRepository
from basic_memory.schemas.search import SearchQuery, SearchItemType
from basic_memory.services.search_service import SearchService
class LinkResolver:
"""Service for resolving markdown links to permalinks.
Uses a combination of exact matching and search-based resolution:
1. Try exact permalink match (fastest)
2. Try exact title match
3. Try exact file path match
4. Try file path with .md extension (for folder/title patterns)
5. Fall back to search for fuzzy matching
"""
def __init__(self, entity_repository: EntityRepository, search_service: SearchService):
"""Initialize with repositories."""
self.entity_repository = entity_repository
self.search_service = search_service
async def resolve_link(
self,
link_text: str,
use_search: bool = True,
strict: bool = False,
source_path: Optional[str] = None,
) -> Optional[Entity]:
"""Resolve a markdown link to a permalink.
Args:
link_text: The link text to resolve
use_search: Whether to use search-based fuzzy matching as fallback
strict: If True, only exact matches are allowed (no fuzzy search fallback)
source_path: Optional path of the source file containing the link.
Used to prefer notes closer to the source (context-aware resolution).
"""
logger.trace(f"Resolving link: {link_text} (source: {source_path})")
# Clean link text and extract any alias
clean_text, alias = self._normalize_link_text(link_text)
# --- Path Resolution ---
# Note: All paths in Basic Memory are stored as POSIX strings (forward slashes)
# for cross-platform compatibility. See entity_repository.py which normalizes
# paths using Path().as_posix(). This allows consistent path operations here.
# --- Relative Path Resolution ---
# Trigger: source_path is provided AND link contains "/"
# Why: Resolve paths like [[nested/deep-note]] relative to source folder first
# Outcome: [[nested/deep-note]] from testing/link-test.md → testing/nested/deep-note.md
if source_path and "/" in clean_text:
source_folder = source_path.rsplit("/", 1)[0] if "/" in source_path else ""
if source_folder:
# Construct relative path from source folder
relative_path = f"{source_folder}/{clean_text}"
# Try with .md extension
if not relative_path.endswith(".md"):
relative_path_md = f"{relative_path}.md"
entity = await self.entity_repository.get_by_file_path(relative_path_md)
if entity:
return entity
# Try as-is (already has extension or is a permalink)
entity = await self.entity_repository.get_by_file_path(relative_path)
if entity:
return entity
# When source_path is provided, use context-aware resolution:
# Check both permalink and title matches, prefer closest to source.
# Example: [[testing]] from folder/note.md prefers folder/testing.md
# over a root testing.md with permalink "testing".
if source_path:
# Gather all potential matches
candidates: list[Entity] = []
# Check permalink match
permalink_entity = await self.entity_repository.get_by_permalink(clean_text)
if permalink_entity:
candidates.append(permalink_entity)
# Check title matches
title_entities = await self.entity_repository.get_by_title(clean_text)
for entity in title_entities:
# Avoid duplicates (permalink match might also be in title matches)
if entity.id not in [c.id for c in candidates]:
candidates.append(entity)
if candidates:
if len(candidates) == 1:
return candidates[0]
else:
# Multiple candidates - pick closest to source
return self._find_closest_entity(candidates, source_path)
# Standard resolution (no source context): permalink first, then title
# 1. Try exact permalink match first (most efficient)
entity = await self.entity_repository.get_by_permalink(clean_text)
if entity:
logger.debug(f"Found exact permalink match: {entity.permalink}")
return entity
# 2. Try exact title match
found = await self.entity_repository.get_by_title(clean_text)
if found:
# Return first match (shortest path) if no source context
entity = found[0]
logger.debug(f"Found title match: {entity.title}")
return entity
# 3. Try file path
found_path = await self.entity_repository.get_by_file_path(clean_text)
if found_path:
logger.debug(f"Found entity with path: {found_path.file_path}")
return found_path
# 4. Try file path with .md extension if not already present
if not clean_text.endswith(".md") and "/" in clean_text:
file_path_with_md = f"{clean_text}.md"
found_path_md = await self.entity_repository.get_by_file_path(file_path_with_md)
if found_path_md:
logger.debug(f"Found entity with path (with .md): {found_path_md.file_path}")
return found_path_md
# In strict mode, don't try fuzzy search - return None if no exact match found
if strict:
return None
# 5. Fall back to search for fuzzy matching (only if not in strict mode)
if use_search and "*" not in clean_text:
results = await self.search_service.search(
query=SearchQuery(text=clean_text, entity_types=[SearchItemType.ENTITY]),
)
if results:
# Look for best match
best_match = min(results, key=lambda x: x.score) # pyright: ignore
logger.trace(
f"Selected best match from {len(results)} results: {best_match.permalink}"
)
if best_match.permalink:
return await self.entity_repository.get_by_permalink(best_match.permalink)
# if we couldn't find anything then return None
return None
def _normalize_link_text(self, link_text: str) -> Tuple[str, Optional[str]]:
"""Normalize link text and extract alias if present.
Args:
link_text: Raw link text from markdown
Returns:
Tuple of (normalized_text, alias or None)
"""
# Strip whitespace
text = link_text.strip()
# Remove enclosing brackets if present
if text.startswith("[[") and text.endswith("]]"):
text = text[2:-2]
# Handle wiki link aliases (format: [[actual|alias]])
alias = None
if "|" in text:
text, alias = text.split("|", 1)
text = text.strip()
alias = alias.strip()
else:
# Strip whitespace from text even if no alias
text = text.strip()
return text, alias
def _find_closest_entity(self, entities: list[Entity], source_path: str) -> Entity:
"""Find the entity closest to the source file path.
Context-aware resolution: prefer notes in the same folder or closer in hierarchy.
Proximity Scoring Algorithm:
- Priority 0: Same folder as source (best match)
- Priority 1-N: Ancestor folders (N = levels up from source)
- Priority 100+N: Descendant folders (N = levels down, deprioritized)
- Priority 1000: Completely unrelated paths (least preferred)
- Ties are broken by shortest absolute path (consistent behavior)
Args:
entities: List of entities with the same title
source_path: Path of the file containing the link
Returns:
The entity closest to the source path
"""
# Extract source folder (everything before the last /)
source_folder = source_path.rsplit("/", 1)[0] if "/" in source_path else ""
def path_proximity(entity: Entity) -> Tuple[int, int]:
"""Return (proximity_score, path_length) for sorting.
Lower is better for both values.
"""
entity_path = entity.file_path
entity_folder = entity_path.rsplit("/", 1)[0] if "/" in entity_path else ""
# Trigger: entity is in the same folder as source
# Why: same-folder notes are most contextually relevant
# Outcome: priority = 0 (best), ties broken by shortest path
if entity_folder == source_folder:
return (0, len(entity_path))
# Trigger: entity is in an ancestor folder of source
# e.g., source is "a/b/c/file.md", entity is "a/b/note.md" -> ancestor
# Why: ancestors are contextually relevant (shared parent context)
# Outcome: priority = levels_up (1, 2, 3...), closer ancestors preferred
if source_folder.startswith(entity_folder + "/") if entity_folder else source_folder:
# Count how many levels up
if entity_folder:
levels_up = source_folder.count("/") - entity_folder.count("/")
else:
# Root level
levels_up = source_folder.count("/") + 1
return (levels_up, len(entity_path))
# Trigger: entity is in a descendant folder of source
# e.g., source is "a/file.md", entity is "a/b/c/note.md" -> descendant
# Why: descendants are less contextually relevant than ancestors
# Outcome: priority = 100 + levels_down, significantly deprioritized
if entity_folder.startswith(source_folder + "/") if source_folder else entity_folder:
if source_folder:
levels_down = entity_folder.count("/") - source_folder.count("/")
else:
# Source is at root
levels_down = entity_folder.count("/") + 1
return (100 + levels_down, len(entity_path))
# Trigger: entity is in a completely unrelated path
# Why: no folder relationship means minimal contextual relevance
# Outcome: priority = 1000, only selected if no related paths exist
return (1000, len(entity_path))
# Sort by proximity (lower is better), then by path length (shorter is better)
return min(entities, key=path_proximity)
