/*
 * Vencord, a modification for Discord's desktop app
 * Copyright (c) 2022 Vendicated and contributors
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
*/

import { Clipboard, React, Toasts, useEffect, useState } from "@webpack/common";

/**
 * Makes a lazy function. On first call, the value is computed.
 * On subsequent calls, the same computed value will be returned
 * @param factory Factory function
 */
export function makeLazy<T>(factory: () => T): () => T {
    let cache: T;
    return () => cache ?? (cache = factory());
}

type AwaiterRes<T> = [T, any, boolean];
interface AwaiterOpts<T> {
    fallbackValue: T,
    deps?: unknown[],
    onError?(e: any): void,
}
/**
 * Await a promise
 * @param factory Factory
 * @param fallbackValue The fallback value that will be used until the promise resolved
 * @returns [value, error, isPending]
 */
export function useAwaiter<T>(factory: () => Promise<T>): AwaiterRes<T | null>;
export function useAwaiter<T>(factory: () => Promise<T>, providedOpts: AwaiterOpts<T>): AwaiterRes<T>;
export function useAwaiter<T>(factory: () => Promise<T>, providedOpts?: AwaiterOpts<T | null>): AwaiterRes<T | null> {
    const opts: Required<AwaiterOpts<T | null>> = Object.assign({
        fallbackValue: null,
        deps: [],
        onError: null,
    }, providedOpts);
    const [state, setState] = useState({
        value: opts.fallbackValue,
        error: null,
        pending: true
    });

    useEffect(() => {
        let isAlive = true;
        if (!state.pending) setState({ ...state, pending: true });

        factory()
            .then(value => isAlive && setState({ value, error: null, pending: false }))
            .catch(error => isAlive && (setState({ value: null, error, pending: false }), opts.onError?.(error)));

        return () => void (isAlive = false);
    }, opts.deps);

    return [state.value, state.error, state.pending];
}

/**
 * Returns a function that can be used to force rerender react components
 */
export function useForceUpdater() {
    const [, set] = useState(0);
    return () => set(s => s + 1);
}

/**
 * A lazy component. The factory method is called on first render. For example useful
 * for const Component = LazyComponent(() => findByDisplayName("...").default)
 * @param factory Function returning a Component
 * @returns Result of factory function
 */
export function LazyComponent<T = any>(factory: () => React.ComponentType<T>) {
    const get = makeLazy(factory);
    return (props: T & JSX.IntrinsicAttributes) => {
        const Component = get();
        return <Component {...props} />;
    };
}

/**
 * Recursively merges defaults into an object and returns the same object
 * @param obj Object
 * @param defaults Defaults
 * @returns obj
 */
export function mergeDefaults<T>(obj: T, defaults: T): T {
    for (const key in defaults) {
        const v = defaults[key];
        if (typeof v === "object" && !Array.isArray(v)) {
            obj[key] ??= {} as any;
            mergeDefaults(obj[key], v);
        } else {
            obj[key] ??= v;
        }
    }
    return obj;
}


/**
 * Join an array of strings in a human readable way (1, 2 and 3)
 * @param elements Elements
 */
export function humanFriendlyJoin(elements: string[]): string;
/**
 * Join an array of strings in a human readable way (1, 2 and 3)
 * @param elements Elements
 * @param mapper Function that converts elements to a string
 */
export function humanFriendlyJoin<T>(elements: T[], mapper: (e: T) => string): string;
export function humanFriendlyJoin(elements: any[], mapper: (e: any) => string = s => s): string {
    const { length } = elements;
    if (length === 0) return "";
    if (length === 1) return mapper(elements[0]);

    let s = "";

    for (let i = 0; i < length; i++) {
        s += mapper(elements[i]);
        if (length - i > 2) s += ", ";
        else if (length - i > 1) s += " and ";
    }

    return s;
}

/**
 * Calls .join(" ") on the arguments
 * classes("one", "two") => "one two"
 */
export function classes(...classes: string[]) {
    return classes.filter(c => typeof c === "string").join(" ");
}

/**
 * Returns a promise that resolves after the specified amount of time
 */
export function sleep(ms: number): Promise<void> {
    return new Promise(r => setTimeout(r, ms));
}

/**
 * Wrap the text in ``` with an optional language
 */
export function makeCodeblock(text: string, language?: string) {
    const chars = "```";
    return `${chars}${language || ""}\n${text.replaceAll("```", "\\`\\`\\`")}\n${chars}`;
}

export function copyWithToast(text: string, toastMessage = "Copied to clipboard!") {
    if (Clipboard.SUPPORTS_COPY) {
        Clipboard.copy(text);
    } else {
        toastMessage = "Your browser does not support copying to clipboard";
    }
    Toasts.show({
        message: toastMessage,
        id: Toasts.genId(),
        type: Toasts.Type.SUCCESS
    });
}

/**
 * Check if obj is a true object: of type "object" and not null or array
 */
export function isObject(obj: unknown): obj is object {
    return typeof obj === "object" && obj !== null && !Array.isArray(obj);
}

/**
 * Returns null if value is not a URL, otherwise return URL object.
 * Avoids having to wrap url checks in a try/catch
 */
export function parseUrl(urlString: string): URL | null {
    try {
        return new URL(urlString);
    } catch {
        return null;
    }
}

/**
 * Checks whether an element is on screen
 */
export const checkIntersecting = (el: Element) => {
    const elementBox = el.getBoundingClientRect();
    const documentHeight = Math.max(document.documentElement.clientHeight, window.innerHeight);
    return !(elementBox.bottom < 0 || elementBox.top - documentHeight >= 0);
};

export function identity<T>(value: T): T {
    return value;
}
