-- +migrate Up
-- Migration to add footprint_geometry column to sites table for building polygons

-- Add footprint geometry column to sites table for storing building polygons
ALTER TABLE sites ADD COLUMN IF NOT EXISTS footprint_geometry GEOMETRY(POLYGON, 4326);

-- Create spatial index for footprint geometry
CREATE INDEX IF NOT EXISTS idx_sites_footprint ON sites USING GIST (footprint_geometry);

-- Add check constraint for geometry validity
ALTER TABLE sites ADD CONSTRAINT chk_sites_footprint_geometry
    CHECK (footprint_geometry IS NULL OR ST_IsValid(footprint_geometry));

-- Add comment for documentation
COMMENT ON COLUMN sites.footprint_geometry IS 'Building footprint polygon geometry in WGS84 (SRID 4326) - stores actual building outlines from OSM data';