from pathlib import Path
from typing import List, Dict, Any

from docforge.nav.resolver import ResolvedNav


class MkDocsNavEmitter:
    """Emit MkDocs-compatible nav structures."""

    def emit(self, nav: ResolvedNav) -> List[Dict[str, Any]]:
        result: List[Dict[str, Any]] = []

        # Home entry (semantic path)
        if nav.home:
            result.append({"Home": nav.home})

        # Group entries
        for group, paths in nav.groups.items():
            entries: List[str] = []
            for p in paths:
                # Convert filesystem path back to docs-relative path
                rel_path = self._to_relative(p, nav._docs_root)
                entries.append(rel_path)
            result.append({group: entries})

        return result

    def _to_relative(self, path: Path, docs_root: Path | None) -> str:
        """
        Convert a filesystem path to a docs-relative path.
        """
        if docs_root and path.is_absolute():
            try:
                path = path.relative_to(docs_root.resolve())
            except ValueError:
                pass
        elif docs_root:
            # Handle relative paths (e.g. starting with 'docs/')
            path_str = path.as_posix()
            docs_root_str = docs_root.as_posix()
            if path_str.startswith(docs_root_str + "/"):
                return path_str[len(docs_root_str) + 1:]
        
        # Fallback for other cases
        return path.as_posix().split("/docs/", 1)[-1]