/***
 * Saves all the features that are passed in to localstorage, so they can be retrieved on the next run
 *
 * Technically, more an Actor then a featuresource, but it fits more neatly this ay
 */
import {FeatureSourceForLayer} from "../FeatureSource";

export default class SaveTileToLocalStorageActor {
    public static readonly storageKey: string = "cached-features";
    public static readonly formatVersion: string = "2"

    constructor(source: FeatureSourceForLayer, tileIndex: number) {
        
        source.features.addCallbackAndRunD(features => {
            const key = `${SaveTileToLocalStorageActor.storageKey}-${source.layer.layerDef.id}-${tileIndex}`
            const now = new Date()

            try {
                if (features.length > 0) {
                    localStorage.setItem(key, JSON.stringify(features));
                }
                // We _still_ write the time to know that this tile is empty!
                SaveTileToLocalStorageActor.MarkVisited(source.layer.layerDef.id, tileIndex, now)
            } catch (e) {
                console.warn("Could not save the features to local storage:", e)
            }
        })
    }


    public static MarkVisited(layerId: string, tileId: number, freshness: Date){
        const key = `${SaveTileToLocalStorageActor.storageKey}-${layerId}-${tileId}`
        try{
            localStorage.setItem(key + "-time", JSON.stringify(freshness.getTime()))
            localStorage.setItem(key + "-format", SaveTileToLocalStorageActor.formatVersion)
        }catch(e){
            console.error("Could not mark tile ", key, "as visited")
        }
    }
}