CREATE SCHEMA IF NOT EXISTS source_gis;

CREATE TABLE IF NOT EXISTS source_gis.datasets (
    dataset_key TEXT PRIMARY KEY,
    title TEXT NOT NULL,
    source_date DATE NOT NULL,
    declared_srid INTEGER,
    effective_srid INTEGER NOT NULL,
    coordinate_note TEXT NOT NULL,
    imported_at TIMESTAMPTZ NOT NULL DEFAULT NOW()
);

CREATE TABLE IF NOT EXISTS source_gis.layers (
    layer_key TEXT PRIMARY KEY,
    dataset_key TEXT NOT NULL REFERENCES source_gis.datasets(dataset_key) ON DELETE CASCADE,
    display_name TEXT NOT NULL,
    source_file TEXT NOT NULL,
    feature_kind TEXT NOT NULL,
    geometry_type TEXT NOT NULL,
    feature_count BIGINT NOT NULL CHECK (feature_count >= 0),
    imported_at TIMESTAMPTZ NOT NULL DEFAULT NOW()
);

CREATE TABLE IF NOT EXISTS source_gis.features (
    layer_key TEXT NOT NULL REFERENCES source_gis.layers(layer_key) ON DELETE CASCADE,
    source_fid BIGINT NOT NULL,
    source_object_id TEXT,
    source_keyword TEXT,
    source_asset_id TEXT,
    source_diameter DOUBLE PRECISION,
    from_node_id TEXT,
    to_node_id TEXT,
    attributes JSONB NOT NULL CHECK (jsonb_typeof(attributes) = 'object'),
    geom geometry(Geometry, 900914) NOT NULL,
    PRIMARY KEY (layer_key, source_fid)
);

ALTER TABLE source_gis.features
    ADD COLUMN IF NOT EXISTS source_diameter DOUBLE PRECISION;

CREATE TABLE IF NOT EXISTS source_gis.element_links (
    element_type TEXT NOT NULL,
    element_id TEXT NOT NULL,
    layer_key TEXT NOT NULL,
    source_fid BIGINT NOT NULL,
    match_method TEXT NOT NULL,
    distance_m DOUBLE PRECISION,
    PRIMARY KEY (element_type, element_id, layer_key),
    FOREIGN KEY (layer_key, source_fid)
        REFERENCES source_gis.features(layer_key, source_fid)
        ON DELETE CASCADE
);

CREATE INDEX IF NOT EXISTS idx_source_gis_layers_dataset
    ON source_gis.layers(dataset_key);
CREATE INDEX IF NOT EXISTS idx_source_gis_features_object_id
    ON source_gis.features(layer_key, source_object_id);
CREATE INDEX IF NOT EXISTS idx_source_gis_features_nodes
    ON source_gis.features(layer_key, from_node_id, to_node_id);
CREATE INDEX IF NOT EXISTS idx_source_gis_features_nodes_reverse
    ON source_gis.features(layer_key, to_node_id, from_node_id);
CREATE INDEX IF NOT EXISTS idx_source_gis_features_geom
    ON source_gis.features USING GIST (geom);
CREATE INDEX IF NOT EXISTS idx_source_gis_element_links_lookup
    ON source_gis.element_links(element_type, element_id);

COMMENT ON SCHEMA source_gis IS
    'Imported source GIS inventories retained separately from the hydraulic model.';
COMMENT ON COLUMN source_gis.datasets.declared_srid IS
    'SRID declared by the source file, which may be incorrect.';
COMMENT ON COLUMN source_gis.datasets.effective_srid IS
    'SRID assigned after validating source coordinates against the project model.';
COMMENT ON COLUMN source_gis.features.attributes IS
    'Original non-geometry GIS fields, including null values, preserved as JSONB.';