import { _flatten as flatten } from '@deck.gl/core';
import MapboxLayer from "./mapbox-layer.js";
const UNDEFINED_BEFORE_ID = '__UNDEFINED__';
/** Insert Deck layers into the mapbox Map according to the user-defined order */
// eslint-disable-next-line complexity, max-statements
export function resolveLayers(map, deck, oldLayers, newLayers) {
    // Wait until map style is loaded
    // @ts-ignore non-public map property
    if (!map || !deck || !map.style || !map.style._loaded) {
        return;
    }
    const layers = flatten(newLayers, Boolean);
    if (oldLayers !== newLayers) {
        // Step 1: remove layers that no longer exist
        const prevLayers = flatten(oldLayers, Boolean);
        const prevLayerIds = new Set(prevLayers.map(l => l.id));
        for (const layer of layers) {
            prevLayerIds.delete(layer.id);
        }
        for (const id of prevLayerIds) {
            if (map.getLayer(id)) {
                map.removeLayer(id);
            }
        }
    }
    // Step 2: add missing layers
    for (const layer of layers) {
        const mapboxLayer = map.getLayer(layer.id);
        if (mapboxLayer) {
            // Mapbox's map.getLayer() had a breaking change in v3.6.0, see https://github.com/visgl/deck.gl/issues/9086
            // @ts-expect-error not typed
            const layerInstance = mapboxLayer.implementation || mapboxLayer;
            layerInstance.setProps(layer.props);
        }
        else {
            map.addLayer(new MapboxLayer({ id: layer.id, deck }), 
            // @ts-expect-error beforeId is not defined in LayerProps
            layer.props.beforeId);
        }
    }
    // Step 3: check the order of layers
    // If beforeId is defined, the deck layer should always render before the mapbox layer [beforeId]
    // If beforeId is not defined, the deck layer should appear after all mapbox layers
    // When two deck layers share the same beforeId, they are rendered in the order that is passed into Deck props.layers
    // @ts-ignore non-public map property
    const mapLayers = map.style._order;
    // Group deck layers by beforeId
    const layerGroups = {};
    for (const layer of layers) {
        // @ts-expect-error beforeId is not defined in LayerProps
        let { beforeId } = layer.props;
        if (!beforeId || !mapLayers.includes(beforeId)) {
            beforeId = UNDEFINED_BEFORE_ID;
        }
        layerGroups[beforeId] = layerGroups[beforeId] || [];
        layerGroups[beforeId].push(layer.id);
    }
    for (const beforeId in layerGroups) {
        const layerGroup = layerGroups[beforeId];
        let lastLayerIndex = beforeId === UNDEFINED_BEFORE_ID ? mapLayers.length : mapLayers.indexOf(beforeId);
        let lastLayerId = beforeId === UNDEFINED_BEFORE_ID ? undefined : beforeId;
        for (let i = layerGroup.length - 1; i >= 0; i--) {
            const layerId = layerGroup[i];
            const layerIndex = mapLayers.indexOf(layerId);
            if (layerIndex !== lastLayerIndex - 1) {
                map.moveLayer(layerId, lastLayerId);
                if (layerIndex > lastLayerIndex) {
                    // The last layer's index have changed
                    lastLayerIndex++;
                }
            }
            lastLayerIndex--;
            lastLayerId = layerId;
        }
    }
}