import { settings } from '$lib/logic/settings';
import { gpxStatistics } from '$lib/logic/statistics';
import { getConvertedDistanceToKilometers } from '$lib/units';
import type { GeoJSONSource } from 'mapbox-gl';
import { get } from 'svelte/store';
import { map } from '$lib/components/map/map';
import { allHidden } from '$lib/logic/hidden';

const { distanceMarkers, distanceUnits } = settings;

const levels = [100, 50, 25, 10, 5, 1];

export class DistanceMarkers {
    updateBinded: () => void = this.update.bind(this);
    unsubscribes: (() => void)[] = [];

    constructor() {
        this.unsubscribes.push(gpxStatistics.subscribe(this.updateBinded));
        this.unsubscribes.push(distanceMarkers.subscribe(this.updateBinded));
        this.unsubscribes.push(distanceUnits.subscribe(this.updateBinded));
        this.unsubscribes.push(allHidden.subscribe(this.updateBinded));
        this.unsubscribes.push(
            map.subscribe((map_) => {
                if (map_) {
                    map_.on('style.import.load', this.updateBinded);
                }
            })
        );
    }

    update() {
        const map_ = get(map);
        if (!map_) return;

        try {
            if (get(distanceMarkers) && !get(allHidden)) {
                let distanceSource: GeoJSONSource | undefined = map_.getSource('distance-markers');
                if (distanceSource) {
                    distanceSource.setData(this.getDistanceMarkersGeoJSON());
                } else {
                    map_.addSource('distance-markers', {
                        type: 'geojson',
                        data: this.getDistanceMarkersGeoJSON(),
                    });
                }
                if (!map_.getLayer('distance-markers')) {
                    map_.addLayer({
                        id: 'distance-markers',
                        type: 'symbol',
                        source: 'distance-markers',
                        filter: [
                            'match',
                            ['get', 'level'],
                            100,
                            ['>=', ['zoom'], 0],
                            50,
                            ['>=', ['zoom'], 7],
                            25,
                            [
                                'any',
                                ['all', ['>=', ['zoom'], 8], ['<=', ['zoom'], 9]],
                                ['>=', ['zoom'], 11],
                            ],
                            10,
                            ['>=', ['zoom'], 10],
                            5,
                            ['>=', ['zoom'], 11],
                            1,
                            ['>=', ['zoom'], 13],
                            false,
                        ],
                        layout: {
                            'text-field': ['get', 'distance'],
                            'text-size': 14,
                            'text-font': ['Open Sans Bold'],
                        },
                        paint: {
                            'text-color': 'black',
                            'text-halo-width': 2,
                            'text-halo-color': 'white',
                        },
                    });
                } else {
                    map_.moveLayer('distance-markers');
                }
            } else {
                if (map_.getLayer('distance-markers')) {
                    map_.removeLayer('distance-markers');
                }
            }
        } catch (e) {
            // No reliable way to check if the map is ready to add sources and layers
            return;
        }
    }

    remove() {
        this.unsubscribes.forEach((unsubscribe) => unsubscribe());
    }

    getDistanceMarkersGeoJSON(): GeoJSON.FeatureCollection {
        let statistics = get(gpxStatistics);

        let features = [];
        let currentTargetDistance = 1;
        for (let i = 0; i < statistics.local.distance.total.length; i++) {
            if (
                statistics.local.distance.total[i] >=
                getConvertedDistanceToKilometers(currentTargetDistance)
            ) {
                let distance = currentTargetDistance.toFixed(0);
                let level = levels.find((level) => currentTargetDistance % level === 0) || 1;
                features.push({
                    type: 'Feature',
                    geometry: {
                        type: 'Point',
                        coordinates: [
                            statistics.local.points[i].getLongitude(),
                            statistics.local.points[i].getLatitude(),
                        ],
                    },
                    properties: {
                        distance,
                        level,
                    },
                } as GeoJSON.Feature);
                currentTargetDistance += 1;
            }
        }

        return {
            type: 'FeatureCollection',
            features,
        };
    }
}