require("globals");
import definition = require("application");
import observable = require("data/observable");
import frame = require("ui/frame");
import cssSelector = require("ui/styling/css-selector");
import * as fileSystemModule from "file-system";
import * as styleScopeModule from "ui/styling/style-scope";
import * as fileResolverModule  from "file-system/file-name-resolver";

var styleScope: typeof styleScopeModule = undefined;

var events = new observable.Observable();
global.moduleMerge(events, exports);

export var launchEvent = "launch";
export var suspendEvent = "suspend";
export var resumeEvent = "resume";
export var exitEvent = "exit";
export var lowMemoryEvent = "lowMemory";
export var uncaughtErrorEvent = "uncaughtError";
export var orientationChangedEvent = "orientationChanged";

export var mainModule: string;
export var mainEntry: frame.NavigationEntry;

export var cssFile: string = "app.css"

export var appSelectors: Array<cssSelector.CssSelector> = [];
export var additionalSelectors: Array<cssSelector.CssSelector> = [];
export var cssSelectors: Array<cssSelector.CssSelector> = [];
export var cssSelectorVersion: number = 0;
export var keyframes: any = {};

export var resources: any = {};

export var onUncaughtError: (error: definition.NativeScriptError) => void = undefined;

export var onLaunch: (context: any) => any = undefined;

export var onSuspend: () => any = undefined;

export var onResume: () => any = undefined;

export var onExit: () => any = undefined;

export var onLowMemory: () => any = undefined;

export var android = undefined;

export var ios = undefined;

export function loadCss(cssFile?: string): Array<cssSelector.CssSelector> {
    if (!cssFile) {
        return undefined;
    }

    var result: Array<cssSelector.CssSelector>;

    var fs: typeof fileSystemModule = require("file-system");
    if (!styleScope) {
        styleScope = require("ui/styling/style-scope");
    }

    var cssFileName = fs.path.join(fs.knownFolders.currentApp().path, cssFile);
    if (fs.File.exists(cssFileName)) {
        var file = fs.File.fromPath(cssFileName);
        var applicationCss = file.readTextSync();
        if (applicationCss) {
            result = parseCss(applicationCss, cssFileName);
        }
    }

    return result;
}

export function mergeCssSelectors(module: any): void {
    //HACK: pass the merged module and work with its exported vars.
    module.cssSelectors = module.appSelectors.slice();
    module.cssSelectors.push.apply(module.cssSelectors, module.additionalSelectors);
    module.cssSelectorVersion++;
}

export function parseCss(cssText: string, cssFileName?: string): Array<cssSelector.CssSelector> {
    if (!styleScope) {
        styleScope = require("ui/styling/style-scope");
    }
    return styleScope.StyleScope.createSelectorsFromCss(cssText, cssFileName, keyframes);
}

export function __onLiveSync() {
    // Close the error page if available and remove the reference from global context.
    if (global.errorPage) {
        global.errorPage.closeModal();
        global.errorPage = undefined;
    }

    try {
        var fileResolver: typeof fileResolverModule = require("file-system/file-name-resolver");

        // Clear file resolver cache to respect newly added files.
        fileResolver.clearCache();

        // Reload app.css in case it was changed.
        loadCss();

        // Reload current page.
        frame.reloadPage();
    } catch (ex) {
        // Show the error as modal page, save reference to the page in global context.
        var builder = require("ui/builder");
        global.errorPage = builder.parse(`<Page><ScrollView><Label text="${ex}" textWrap="true" style="color: red;" /></ScrollView></Page>`);
        global.errorPage.showModal();
    }
}