"""Reference resource for common CRS definitions."""
from __future__ import annotations
from fastmcp import Context
from src.app import mcp
from src.shared.reference import get_common_crs
@mcp.resource(
uri="reference://crs/common/{coverage}",
name="Common CRS Reference",
description=(
"Curated reference of commonly-used coordinate reference systems organized by use case "
"and geographic coverage. Includes global systems (EPSG:4326, EPSG:3857), continental "
"projections, and regional UTM zones. Provides EPSG codes, names, areas of use, and "
"guidance on appropriate applications. Essential for raster_reproject and vector_reproject "
"operations to select appropriate target coordinate systems. Filter by coverage: "
"'global', 'continental', 'utm', or 'all'."
),
)
def list_common_crs(
coverage: str = "all",
ctx: Context | None = None,
) -> dict:
"""Return curated set of common CRS definitions."""
normalized = None if not coverage or coverage.lower() == "all" else coverage
entries = get_common_crs(coverage=normalized)
if ctx and normalized:
ctx.debug(f"Filtered common CRS by coverage='{normalized}' -> {len(entries)} entries")
return {"entries": entries, "total": len(entries)}
