/*
Copyright 2022 The Matrix.org Foundation C.I.C.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

import classNames from "classnames";
import React, { FunctionComponent, Key, PropsWithChildren, ReactNode } from "react";

import { MenuItemRadio } from "../../accessibility/context_menu/MenuItemRadio";
import { ButtonEvent } from "../views/elements/AccessibleButton";
import ContextMenu, { aboveLeftOf, ChevronFace, ContextMenuButton, useContextMenu } from "./ContextMenu";

export type GenericDropdownMenuOption<T> = {
    key: T;
    label: ReactNode;
    description?: ReactNode;
    adornment?: ReactNode;
};

export type GenericDropdownMenuGroup<T> = GenericDropdownMenuOption<T> & {
    options: GenericDropdownMenuOption<T>[];
};

export type GenericDropdownMenuItem<T> = GenericDropdownMenuGroup<T> | GenericDropdownMenuOption<T>;

export function GenericDropdownMenuOption<T extends Key>({
    label,
    description,
    onClick,
    isSelected,
    adornment,
}: GenericDropdownMenuOption<T> & {
    onClick: (ev: ButtonEvent) => void;
    isSelected: boolean;
}): JSX.Element {
    return <MenuItemRadio
        active={isSelected}
        className="mx_GenericDropdownMenu_Option mx_GenericDropdownMenu_Option--item"
        onClick={onClick}
    >
        <div className="mx_GenericDropdownMenu_Option--label">
            <span>{ label }</span>
            <span>{ description }</span>
        </div>
        { adornment }
    </MenuItemRadio>;
}

export function GenericDropdownMenuGroup<T extends Key>({
    label,
    description,
    adornment,
    children,
}: PropsWithChildren<GenericDropdownMenuOption<T>>): JSX.Element {
    return <>
        <div className="mx_GenericDropdownMenu_Option mx_GenericDropdownMenu_Option--header">
            <div className="mx_GenericDropdownMenu_Option--label">
                <span>{ label }</span>
                <span>{ description }</span>
            </div>
            { adornment }
        </div>
        { children }
    </>;
}

function isGenericDropdownMenuGroup<T>(
    item: GenericDropdownMenuItem<T>,
): item is GenericDropdownMenuGroup<T> {
    return "options" in item;
}

type WithKeyFunction<T> = T extends Key ? {
    toKey?: (key: T) => Key;
} : {
    toKey: (key: T) => Key;
};

type IProps<T> = WithKeyFunction<T> & {
    value: T;
    options: (readonly GenericDropdownMenuOption<T>[] | readonly GenericDropdownMenuGroup<T>[]);
    onChange: (option: T) => void;
    selectedLabel: (option: GenericDropdownMenuItem<T> | null | undefined) => ReactNode;
    onOpen?: (ev: ButtonEvent) => void;
    onClose?: (ev: ButtonEvent) => void;
    className?: string;
    AdditionalOptions?: FunctionComponent<{
        menuDisplayed: boolean;
        closeMenu: () => void;
        openMenu: () => void;
    }>;
};

export function GenericDropdownMenu<T>(
    { value, onChange, options, selectedLabel, onOpen, onClose, toKey, className, AdditionalOptions }: IProps<T>,
): JSX.Element {
    const [menuDisplayed, button, openMenu, closeMenu] = useContextMenu<HTMLElement>();

    const selected: GenericDropdownMenuItem<T> | null = options
        .flatMap(it => isGenericDropdownMenuGroup(it) ? [it, ...it.options] : [it])
        .find(option => toKey ? toKey(option.key) === toKey(value) : option.key === value);
    let contextMenuOptions: JSX.Element;
    if (options && isGenericDropdownMenuGroup(options[0])) {
        contextMenuOptions = <>
            { options.map(group => (
                <GenericDropdownMenuGroup
                    key={toKey?.(group.key) ?? group.key}
                    label={group.label}
                    description={group.description}
                    adornment={group.adornment}
                >
                    { group.options.map(option => (
                        <GenericDropdownMenuOption
                            key={toKey?.(option.key) ?? option.key}
                            label={option.label}
                            description={option.description}
                            onClick={(ev: ButtonEvent) => {
                                onChange(option.key);
                                closeMenu();
                                onClose?.(ev);
                            }}
                            adornment={option.adornment}
                            isSelected={option === selected}
                        />
                    )) }
                </GenericDropdownMenuGroup>
            )) }
        </>;
    } else {
        contextMenuOptions = <>
            { options.map(option => (
                <GenericDropdownMenuOption
                    key={toKey?.(option.key) ?? option.key}
                    label={option.label}
                    description={option.description}
                    onClick={(ev: ButtonEvent) => {
                        onChange(option.key);
                        closeMenu();
                        onClose?.(ev);
                    }}
                    adornment={option.adornment}
                    isSelected={option === selected}
                />
            )) }
        </>;
    }
    const contextMenu = menuDisplayed ? <ContextMenu
        onFinished={closeMenu}
        chevronFace={ChevronFace.Top}
        wrapperClassName={classNames("mx_GenericDropdownMenu_wrapper", className)}
        {...aboveLeftOf(button.current.getBoundingClientRect())}
    >
        { contextMenuOptions }
        { AdditionalOptions && (
            <AdditionalOptions menuDisplayed={menuDisplayed} openMenu={openMenu} closeMenu={closeMenu} />
        ) }
    </ContextMenu> : null;
    return <>
        <ContextMenuButton
            className="mx_GenericDropdownMenu_button"
            inputRef={button}
            isExpanded={menuDisplayed}
            onClick={(ev: ButtonEvent) => {
                openMenu();
                onOpen?.(ev);
            }}
        >
            { selectedLabel(selected) }
        </ContextMenuButton>
        { contextMenu }
    </>;
}
