// Type definitions for CSS Font Loading Module Level 3
// Project: https://drafts.csswg.org/css-font-loading/
// Definitions by: slikts <https://github.com/slikts>
// Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped

export type FontFaceLoadStatus = 'unloaded' | 'loading' | 'loaded' | 'error';
export type FontFaceSetLoadStatus = 'loading' | 'loaded';
export type BinaryData = ArrayBuffer | ArrayBufferView;

export interface FontFaceDescriptors {
    style?: string;
    weight?: string;
    stretch?: string;
    unicodeRange?: string;
    variant?: string;
    featureSettings?: string;
}

export interface FontFaceSetLoadEventInit extends EventInit {
    fontfaces?: FontFace[];
}

export interface FontFaceSetEventMap {
    "loading": (this: FontFaceSet, event: FontFaceSetLoadEvent) => any;
    "loadingdone": (this: FontFaceSet, event: FontFaceSetLoadEvent) => any;
    "loadingerror": (this: FontFaceSet, event: FontFaceSetLoadEvent) => any;
}

export interface FontFaceSet extends Set<FontFace>, EventTarget {
    // events for when loading state changes
    onloading: ((this: FontFaceSet, event: FontFaceSetLoadEvent) => any) | null;
    onloadingdone: ((this: FontFaceSet, event: FontFaceSetLoadEvent) => any) | null;
    onloadingerror: ((this: FontFaceSet, event: FontFaceSetLoadEvent) => any) | null;

    // EventTarget
    addEventListener<K extends keyof FontFaceSetEventMap>(type: K, listener: FontFaceSetEventMap[K], options?: boolean | AddEventListenerOptions): void;
    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
    removeEventListener<K extends keyof FontFaceSetEventMap>(type: K, listener: FontFaceSetEventMap[K], options?: boolean | EventListenerOptions): void;
    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;

    // check and start loads if appropriate
    // and fulfill promise when all loads complete
    load(font: string, text?: string): Promise<FontFace[]>;
    // return whether all fonts in the fontlist are loaded
    // (does not initiate load if not available)
    check(font: string, text?: string): boolean;

    // async notification that font loading and layout operations are done
    readonly ready: Promise<FontFaceSet>;

    // loading state, "loading" while one or more fonts loading, "loaded" otherwise
    readonly status: FontFaceSetLoadStatus;
}

declare global {
    class FontFace {
        constructor(family: string, source: string | BinaryData, descriptors?: FontFaceDescriptors);
        load(): Promise<FontFace>;

        family: string;
        style: string;
        weight: string;
        stretch: string;
        unicodeRange: string;
        variant: string;
        featureSettings: string;
        variationSettings: string;
        display: string;
        readonly status: FontFaceLoadStatus;
        readonly loaded: Promise<FontFace>;
    }

    class FontFaceSetLoadEvent extends Event {
        constructor(type: string, eventInitDict?: FontFaceSetLoadEventInit);
        readonly fontfaces: FontFace[];
    }

    interface Document {
        fonts: FontFaceSet;
    }

    interface WorkerGlobalScope {
        fonts: FontFaceSet;
    }
}