var map = L.map('map')//.setView([55.68, 12.57], 13);
L.tileLayer('https://tile.openstreetmap.org/{z}/{x}/{y}.png', {
    maxZoom: 19,
    attribution: '&copy; <a href="http://www.openstreetmap.org/copyright">OpenStreetMap</a>'
}).addTo(map);

let known_store_chains;
let icons = {};

var markers =  L.featureGroup()
var polygons =  L.featureGroup()
var heatmap =  L.featureGroup()

const queryString = window.location.search;
const urlParams = new URLSearchParams(queryString);
if (!urlParams.has('markers') || urlParams.get('markers') == "1") {
	markers.addTo(map);
}
if (!urlParams.has('polygons') || urlParams.get('polygons') == "1") {
	polygons.addTo(map);
}
if (!urlParams.has('heatmap') || urlParams.get('heatmap') == "1") {
	heatmap.addTo(map);
}



const CategoryField = document.getElementById('Category');
const CountryField = document.getElementById('Country');
const LoadingIndicator = document.getElementById('LoadingIndicator');
const SubmitButton = document.getElementById('SubmitButton');
const form = document.getElementById('QueryForm');
const heatmap_intensity_element = document.getElementById("HeatmapIntensity");
const heatmap_radius_element = document.getElementById("HeatmapRadius");

var shops;

const DefaultCategory = "shop:supermarket";
const DefaultCountry = "Denmark";
var Categories = []

var overlayMaps = {
    "POI markers": markers,
    "Nearest POI polygons": polygons,
    "POI heatmap": heatmap
};

var layerControl = L.control.layers({},overlayMaps).addTo(map);



form.addEventListener('submit', (event) => {
	event.preventDefault(); // Prevents the default form submission
	if (SubmitButton.disabled) { // Disallow double queries
		return;
	}
	SubmitButton.disabled = true;
	LoadingIndicator.hidden = false;

	const url = new URL(location);
	url.searchParams.set("category", CategoryField.value);
	url.searchParams.set("country", CountryField.value);
	history.pushState({}, "", url);

	markers.clearLayers();
	polygons.clearLayers();
	fetchAll(CountryField.value, CategoryField.value);
});

heatmap_intensity_element.addEventListener('input', (event) => {
    changeHeatmap();
});

heatmap_radius_element.addEventListener('input', (event) => {
    changeHeatmap();
});

function changeHeatmap() {
    const url = new URL(location);
    url.searchParams.set("HeatmapIntensity", heatmap_intensity_element.value);
    history.pushState({}, "", url);
    url.searchParams.set("HeatmapRadius", heatmap_radius_element.value);
    history.pushState({}, "", url);
    drawHeatmap();
}

function alterHeatMapParameter(event) {
    event.srcElement.value;
}

async function fetchCategories() {
	let response;
	try {
			response = await fetch("categories.json");

		if (!response.ok) {
			// If the response status is not OK, throw an error
			throw new Error(`HTTP error! Status: ${response.status}`);
		}
		} catch (error) {
			alert(`Failed to fetch categories\n${error.message}`)
		}
	categories = await response.json();
	CategoryField.pattern = categories.join('|');
	const CategoriesDataList = document.getElementById('CategoriesDataList');
	categories.forEach(function(item){
		var option = document.createElement('option');
		option.value = item;
		option.innerHTML = item;
		CategoriesDataList.appendChild(option);
	});


}

async function fetchChains() {
	try {
		const response = await fetch("chains.json");
		known_store_chains = await response.json();
		if (!response.ok) {
			// If the response status is not OK, throw an error
			throw new Error(`HTTP error! Status: ${response.status}`);
		}
	} catch (error) {
		alert(`Failed to fetch chains\n${error.message}`)
	}

    icons["Unknown"] = L.icon({
        iconUrl: 'icons/Unknown.png',
        iconSize: [10, 16],
        iconAnchor: [5, 8],
    });
    for (let known_store_chain in known_store_chains) {
        icons[known_store_chain] = L.icon({
            iconUrl: `icons/${known_store_chain}.png`,
            iconAnchor: [8, 8],
        });
    }

    const queryString = window.location.search;
    const urlParams = new URLSearchParams(queryString);
    const category_url_param = urlParams.get('category')
    const country_url_param = urlParams.get('country')
		//console.log(country_url_param)
    const category_field_value = CategoryField.value
    const country_field_value = CountryField.value
    // Retains saved value from input field on reload
    if (category_url_param)
    {
        CategoryField.value = category_url_param;

    } else if (category_field_value == "") {
        CategoryField.value = DefaultCategory;
    }

    if (country_url_param)
    {
        CountryField.value = country_url_param;

    } else if (country_field_value == "") {
        CountryField.value = DefaultCountry;
    }

		fetchAll(CountryField.value, CategoryField.value);
}


function addPolygon(store) {
    let color;
    if (known_store_chains.hasOwnProperty(store.brand)) {
        color = known_store_chains[store.brand];
    } else {
        color = 'grey';
    }
    L.polygon(store.polygon, {color: color}).addTo(polygons);
}

function addShop(shop) {
    let icon;

    if (known_store_chains.hasOwnProperty(shop.brand)){
        icon = icons[shop.brand];
    } else {
        icon = icons["Unknown"];
    }

    L.marker([shop.lat, shop.long], {
        title: shop.name,
        icon: icon,
    }).addTo(markers);
    addPolygon(shop);
}

function drawHeatmap() {
  const queryString = window.location.search;
  const urlParams = new URLSearchParams(queryString);
  const HeatmapIntensityUrlParam = urlParams.get("HeatmapIntensity")
  if (HeatmapIntensityUrlParam){
     heatmap_intensity_element.value = HeatmapIntensityUrlParam;
  }
  const HeatmapRadiusUrlParam = urlParams.get("HeatmapRadius")
  if (HeatmapRadiusUrlParam){
     heatmap_radius_element.value = HeatmapRadiusUrlParam;
  }

  heatmap.clearLayers();
  const shops_heatmap_format = shops.map(r => [r.lat, r.long, parseInt(heatmap_intensity_element.value)]); // Convert data to heatmap format
  var heat = L.heatLayer(shops_heatmap_format, {radius: parseInt(heatmap_radius_element.value)}).addTo(heatmap);
}

async function fetchAll(country, category) {
	if (CountryField.value == "Denmark") {
		console.log('Focusing Copenhagen')
		map.setView([55.68, 12.57], 13);
	} else if(CountryField.value == "Germany") {
		console.log('Focusing Hamburg')
		map.setView([53.56, 10.01], 12);
	}

	let response;
	try {
		response = await fetch(`all.json?country=${country}&category=${category}`)
		if (!response.ok) {
			// If the response status is not OK, throw an error
			throw new Error(`HTTP error! Status: ${response.status}`);
		}
	} catch (error) {
		alert(`Failed to fetch data\n${error.message}`)
	}

	shops = await response.json();

  shops.forEach((shop) => addShop(shop)); // Add icons and polygons

  drawHeatmap();

  LoadingIndicator.hidden = true;
  SubmitButton.disabled = false;
}

fetchChains();
fetchCategories();