import {Utils} from "./Utils";
import {ElementStorage} from "./Logic/ElementStorage";
import {Changes} from "./Logic/Osm/Changes";
import {OsmConnection} from "./Logic/Osm/OsmConnection";
import Locale from "./UI/i18n/Locale";
import {UIEventSource} from "./Logic/UIEventSource";
import {LocalStorageSource} from "./Logic/Web/LocalStorageSource";
import {QueryParameters} from "./Logic/Web/QueryParameters";
import {MangroveIdentity} from "./Logic/Web/MangroveReviews";
import InstalledThemes from "./Logic/Actors/InstalledThemes";
import BaseLayer from "./Models/BaseLayer";
import Loc from "./Models/Loc";
import Constants from "./Models/Constants";
import TitleHandler from "./Logic/Actors/TitleHandler";
import PendingChangesUploader from "./Logic/Actors/PendingChangesUploader";
import FeaturePipeline from "./Logic/FeatureSource/FeaturePipeline";
import FilteredLayer from "./Models/FilteredLayer";
import ChangeToElementsActor from "./Logic/Actors/ChangeToElementsActor";
import LayoutConfig from "./Models/ThemeConfig/LayoutConfig";
import {BBox} from "./Logic/GeoOperations";

/**
 * Contains the global state: a bunch of UI-event sources
 */

export default class State {
    // The singleton of the global state
    public static state: State;

    public readonly layoutToUse = new UIEventSource<LayoutConfig>(undefined, "layoutToUse");

    /**
     The mapping from id -> UIEventSource<properties>
     */
    public allElements: ElementStorage;
    /**
     THe change handler
     */
    public changes: Changes;
    /**
     The leaflet instance of the big basemap
     */
    public leafletMap = new UIEventSource<L.Map>(undefined, "leafletmap");
    /**
     * Background layer id
     */
    public availableBackgroundLayers: UIEventSource<BaseLayer[]>;
    /**
     The user credentials
     */
    public osmConnection: OsmConnection;

    public mangroveIdentity: MangroveIdentity;

    public favouriteLayers: UIEventSource<string[]>;

    public filteredLayers: UIEventSource<FilteredLayer[]> = new UIEventSource<FilteredLayer[]>([], "filteredLayers");

    /**
     The latest element that was selected
     */
    public readonly selectedElement = new UIEventSource<any>(
        undefined,
        "Selected element"
    );

    public readonly featureSwitchUserbadge: UIEventSource<boolean>;
    public readonly featureSwitchSearch: UIEventSource<boolean>;
    public readonly featureSwitchBackgroundSlection: UIEventSource<boolean>;
    public readonly featureSwitchAddNew: UIEventSource<boolean>;
    public readonly featureSwitchWelcomeMessage: UIEventSource<boolean>;
    public readonly featureSwitchIframe: UIEventSource<boolean>;
    public readonly featureSwitchMoreQuests: UIEventSource<boolean>;
    public readonly featureSwitchShareScreen: UIEventSource<boolean>;
    public readonly featureSwitchGeolocation: UIEventSource<boolean>;
    public readonly featureSwitchIsTesting: UIEventSource<boolean>;
    public readonly featureSwitchIsDebugging: UIEventSource<boolean>;
    public readonly featureSwitchShowAllQuestions: UIEventSource<boolean>;
    public readonly featureSwitchApiURL: UIEventSource<string>;
    public readonly featureSwitchFilter: UIEventSource<boolean>;
    public readonly featureSwitchEnableExport: UIEventSource<boolean>;
    public readonly featureSwitchFakeUser: UIEventSource<boolean>;
    public readonly featureSwitchExportAsPdf: UIEventSource<boolean>;
    public readonly overpassUrl: UIEventSource<string>;
    public readonly overpassTimeout: UIEventSource<number>;
    public readonly overpassMaxZoom: UIEventSource<number> = new UIEventSource<number>(undefined);

    public featurePipeline: FeaturePipeline;


    /**
     * The map location: currently centered lat, lon and zoom
     */
    public readonly locationControl = new UIEventSource<Loc>(undefined, "locationControl");

    /**
     * The current visible extent of the screen
     */
    public readonly currentBounds = new UIEventSource<BBox>(undefined)
    
    public backgroundLayer;
    public readonly backgroundLayerId: UIEventSource<string>;

    /* Last location where a click was registered
     */
    public readonly LastClickLocation: UIEventSource<{
        lat: number;
        lon: number;
    }> = new UIEventSource<{ lat: number; lon: number }>(undefined);

    /**
     * The location as delivered by the GPS
     */
    public currentGPSLocation: UIEventSource<{
        latlng: { lat: number; lng: number };
        accuracy: number;
    }> = new UIEventSource<{
        latlng: { lat: number; lng: number };
        accuracy: number;
    }>(undefined);
    public layoutDefinition: string;
    public installedThemes: UIEventSource<{ layout: LayoutConfig; definition: string }[]>;

    public downloadControlIsOpened: UIEventSource<boolean> =
        QueryParameters.GetQueryParameter(
            "download-control-toggle",
            "false",
            "Whether or not the download panel is shown"
        ).map<boolean>(
            (str) => str !== "false",
            [],
            (b) => "" + b
        );

    public filterIsOpened: UIEventSource<boolean> =
        QueryParameters.GetQueryParameter(
            "filter-toggle",
            "false",
            "Whether or not the filter view is shown"
        ).map<boolean>(
            (str) => str !== "false",
            [],
            (b) => "" + b
        );

    public welcomeMessageOpenedTab = QueryParameters.GetQueryParameter(
        "tab",
        "0",
        `The tab that is shown in the welcome-message. 0 = the explanation of the theme,1 = OSM-credits, 2 = sharescreen, 3 = more themes, 4 = about mapcomplete (user must be logged in and have >${Constants.userJourney.mapCompleteHelpUnlock} changesets)`
    ).map<number>(
        (str) => (isNaN(Number(str)) ? 0 : Number(str)),
        [],
        (n) => "" + n
    );

    constructor(layoutToUse: LayoutConfig) {
        const self = this;

        this.layoutToUse.setData(layoutToUse);

        // -- Location control initialization
        {
            const zoom = State.asFloat(
                QueryParameters.GetQueryParameter(
                    "z",
                    "" + (layoutToUse?.startZoom ?? 1),
                    "The initial/current zoom level"
                ).syncWith(LocalStorageSource.Get("zoom"))
            );
            const lat = State.asFloat(
                QueryParameters.GetQueryParameter(
                    "lat",
                    "" + (layoutToUse?.startLat ?? 0),
                    "The initial/current latitude"
                ).syncWith(LocalStorageSource.Get("lat"))
            );
            const lon = State.asFloat(
                QueryParameters.GetQueryParameter(
                    "lon",
                    "" + (layoutToUse?.startLon ?? 0),
                    "The initial/current longitude of the app"
                ).syncWith(LocalStorageSource.Get("lon"))
            );

            this.locationControl.setData({
                zoom: Utils.asFloat(zoom.data),
                lat: Utils.asFloat(lat.data),
                lon: Utils.asFloat(lon.data),
            })
            this.locationControl.addCallback((latlonz) => {
                // Sync th location controls
                zoom.setData(latlonz.zoom);
                lat.setData(latlonz.lat);
                lon.setData(latlonz.lon);
            });

            this.layoutToUse.addCallback((layoutToUse) => {
                const lcd = self.locationControl.data;
                lcd.zoom = lcd.zoom ?? layoutToUse?.startZoom;
                lcd.lat = lcd.lat ?? layoutToUse?.startLat;
                lcd.lon = lcd.lon ?? layoutToUse?.startLon;
                self.locationControl.ping();
            });
        }

        // Helper function to initialize feature switches
        function featSw(
            key: string,
            deflt: (layout: LayoutConfig) => boolean,
            documentation: string
        ): UIEventSource<boolean> {
            const queryParameterSource = QueryParameters.GetQueryParameter(
                key,
                undefined,
                documentation
            );
            // I'm so sorry about someone trying to decipher this

            // It takes the current layout, extracts the default value for this query parameter. A query parameter event source is then retrieved and flattened
            return UIEventSource.flatten(
                self.layoutToUse.map((layout) => {
                    const defaultValue = deflt(layout);
                    const queryParam = QueryParameters.GetQueryParameter(
                        key,
                        "" + defaultValue,
                        documentation
                    );
                    return queryParam.map((str) =>
                        str === undefined ? defaultValue : str !== "false"
                    );
                }),
                [queryParameterSource]
            );
        }

        // Feature switch initialization - not as a function as the UIEventSources are readonly
        {
            this.featureSwitchUserbadge = featSw(
                "fs-userbadge",
                (layoutToUse) => layoutToUse?.enableUserBadge ?? true,
                "Disables/Enables the user information pill (userbadge) at the top left. Disabling this disables logging in and thus disables editing all together, effectively putting MapComplete into read-only mode."
            );
            this.featureSwitchSearch = featSw(
                "fs-search",
                (layoutToUse) => layoutToUse?.enableSearch ?? true,
                "Disables/Enables the search bar"
            );
            this.featureSwitchBackgroundSlection = featSw(
                "fs-background",
                (layoutToUse) => layoutToUse?.enableBackgroundLayerSelection ?? true,
                "Disables/Enables the background layer control"
            );

            this.featureSwitchFilter = featSw(
                "fs-filter",
                (layoutToUse) => layoutToUse?.enableLayers ?? true,
                "Disables/Enables the filter"
            );
            this.featureSwitchAddNew = featSw(
                "fs-add-new",
                (layoutToUse) => layoutToUse?.enableAddNewPoints ?? true,
                "Disables/Enables the 'add new feature'-popup. (A theme without presets might not have it in the first place)"
            );
            this.featureSwitchWelcomeMessage = featSw(
                "fs-welcome-message",
                () => true,
                "Disables/enables the help menu or welcome message"
            );
            this.featureSwitchIframe = featSw(
                "fs-iframe",
                () => false,
                "Disables/Enables the iframe-popup"
            );
            this.featureSwitchMoreQuests = featSw(
                "fs-more-quests",
                (layoutToUse) => layoutToUse?.enableMoreQuests ?? true,
                "Disables/Enables the 'More Quests'-tab in the welcome message"
            );
            this.featureSwitchShareScreen = featSw(
                "fs-share-screen",
                (layoutToUse) => layoutToUse?.enableShareScreen ?? true,
                "Disables/Enables the 'Share-screen'-tab in the welcome message"
            );
            this.featureSwitchGeolocation = featSw(
                "fs-geolocation",
                (layoutToUse) => layoutToUse?.enableGeolocation ?? true,
                "Disables/Enables the geolocation button"
            );
            this.featureSwitchShowAllQuestions = featSw(
                "fs-all-questions",
                (layoutToUse) => layoutToUse?.enableShowAllQuestions ?? false,
                "Always show all questions"
            );

            this.featureSwitchEnableExport = featSw(
                "fs-export",
                (layoutToUse) => layoutToUse?.enableExportButton ?? false,
                "Enable the export as GeoJSON and CSV button"
            );
            this.featureSwitchExportAsPdf = featSw(
                "fs-pdf",
                (layoutToUse) => layoutToUse?.enablePdfDownload ?? false,
                "Enable the PDF download button"
            );


            this.featureSwitchIsTesting = QueryParameters.GetQueryParameter(
                "test",
                "false",
                "If true, 'dryrun' mode is activated. The app will behave as normal, except that changes to OSM will be printed onto the console instead of actually uploaded to osm.org"
            ).map(
                (str) => str === "true",
                [],
                (b) => "" + b
            );

            this.featureSwitchIsDebugging = QueryParameters.GetQueryParameter(
                "debug",
                "false",
                "If true, shows some extra debugging help such as all the available tags on every object"
            ).map(
                (str) => str === "true",
                [],
                (b) => "" + b
            );

            this.featureSwitchFakeUser = QueryParameters.GetQueryParameter("fake-user", "false",
                "If true, 'dryrun' mode is activated and a fake user account is loaded")
                .map(str => str === "true", [], b => "" + b);


            this.featureSwitchApiURL = QueryParameters.GetQueryParameter(
                "backend",
                "osm",
                "The OSM backend to use - can be used to redirect mapcomplete to the testing backend when using 'osm-test'"
            );

            this.overpassUrl = QueryParameters.GetQueryParameter("overpassUrl",
                layoutToUse?.overpassUrl,
                "Point mapcomplete to a different overpass-instance. Example: https://overpass-api.de/api/interpreter"
            )

            this.overpassTimeout = QueryParameters.GetQueryParameter("overpassTimeout",
                "" + layoutToUse?.overpassTimeout,
                "Set a different timeout (in seconds) for queries in overpass")
                .map(str => Number(str), [], n => "" + n)

            this.featureSwitchUserbadge.addCallbackAndRun(userbadge => {
                if (!userbadge) {
                    this.featureSwitchAddNew.setData(false)
                }
            })
        }
        {
            // Some other feature switches
            const customCssQP = QueryParameters.GetQueryParameter(
                "custom-css",
                "",
                "If specified, the custom css from the given link will be loaded additionaly"
            );
            if (customCssQP.data !== undefined && customCssQP.data !== "") {
                Utils.LoadCustomCss(customCssQP.data);
            }

            this.backgroundLayerId = QueryParameters.GetQueryParameter(
                "background",
                layoutToUse?.defaultBackgroundId ?? "osm",
                "The id of the background layer to start with"
            );
        }

        if (Utils.runningFromConsole) {
            return;
        }

        this.osmConnection = new OsmConnection(
            this.featureSwitchIsTesting.data,
            this.featureSwitchFakeUser.data,
            QueryParameters.GetQueryParameter(
                "oauth_token",
                undefined,
                "Used to complete the login"
            ),
            layoutToUse?.id,
            true,
            // @ts-ignore
            this.featureSwitchApiURL.data
        );

        this.allElements = new ElementStorage();
        this.changes = new Changes();

        new ChangeToElementsActor(this.changes, this.allElements)

        new PendingChangesUploader(this.changes, this.selectedElement);

        this.mangroveIdentity = new MangroveIdentity(
            this.osmConnection.GetLongPreference("identity", "mangrove")
        );

        this.installedThemes = new InstalledThemes(
            this.osmConnection
        ).installedThemes;

        // Important: the favourite layers are initialized _after_ the installed themes, as these might contain an installedTheme
        this.favouriteLayers = LocalStorageSource.Get("favouriteLayers")
            .syncWith(this.osmConnection.GetLongPreference("favouriteLayers"))
            .map(
                (str) => Utils.Dedup(str?.split(";")) ?? [],
                [],
                (layers) => Utils.Dedup(layers)?.join(";")
            );

        Locale.language.syncWith(this.osmConnection.GetPreference("language"));

        Locale.language
            .addCallback((currentLanguage) => {
                const layoutToUse = self.layoutToUse.data;
                if (layoutToUse === undefined) {
                    return;
                }
                if (this.layoutToUse.data.language.indexOf(currentLanguage) < 0) {
                    console.log(
                        "Resetting language to",
                        layoutToUse.language[0],
                        "as",
                        currentLanguage,
                        " is unsupported"
                    );
                    // The current language is not supported -> switch to a supported one
                    Locale.language.setData(layoutToUse.language[0]);
                }
            })
            .ping();

        new TitleHandler(this.layoutToUse, this.selectedElement, this.allElements);
    }

    private static asFloat(source: UIEventSource<string>): UIEventSource<number> {
        return source.map(
            (str) => {
                let parsed = parseFloat(str);
                return isNaN(parsed) ? undefined : parsed;
            },
            [],
            (fl) => {
                if (fl === undefined || isNaN(fl)) {
                    return undefined;
                }
                return ("" + fl).substr(0, 8);
            }
        );
    }
}