/*
Copyright 2021 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 {tag, text, classNames} from "./general/html.js";
import {BaseUpdateView} from "./general/BaseUpdateView.js";

/*
optimization to not use a sub view when changing between img and text
because there can be many many instances of this view
*/

export class AvatarView extends BaseUpdateView {
    /**
     * @param  {ViewModel} value   view model with {avatarUrl, avatarColorNumber, avatarTitle, avatarLetter}
     * @param  {Number} size
     */
    constructor(value, size) {
        super(value);
        this._root = null;
        this._avatarUrl = null;
        this._avatarTitle = null;
        this._avatarLetter = null;
        this._size = size;
    }

    _avatarUrlChanged() {
        if (this.value.avatarUrl(this._size) !== this._avatarUrl) {
            this._avatarUrl = this.value.avatarUrl(this._size);
            return true;
        }
        return false;
    }

    _avatarTitleChanged() {
        if (this.value.avatarTitle !== this._avatarTitle) {
            this._avatarTitle = this.value.avatarTitle;
            return true;
        }
        return false;
    }

    _avatarLetterChanged() {
        if (this.value.avatarLetter !== this._avatarLetter) {
            this._avatarLetter = this.value.avatarLetter;
            return true;
        }
        return false;
    }

    mount(options) {
        this._avatarUrlChanged();
        this._avatarLetterChanged();
        this._avatarTitleChanged();
        this._root = renderStaticAvatar(this.value, this._size);
        // takes care of update being called when needed
        super.mount(options);
        return this._root;
    }

    root() {
        return this._root;
    }

    update(vm) {
        // important to always call _...changed for every prop 
        if (this._avatarUrlChanged()) {
            // avatarColorNumber won't change, it's based on room/user id
            const bgColorClass = `usercolor${vm.avatarColorNumber}`;
            if (vm.avatarUrl(this._size)) {
                this._root.replaceChild(renderImg(vm, this._size), this._root.firstChild);
                this._root.classList.remove(bgColorClass);
            } else {
                this._root.replaceChild(text(vm.avatarLetter), this._root.firstChild);
                this._root.classList.add(bgColorClass);
            }
        }
        const hasAvatar = !!vm.avatarUrl(this._size);
        if (this._avatarTitleChanged() && hasAvatar) {
            const img = this._root.firstChild;
            img.setAttribute("title", vm.avatarTitle);
        }
        if (this._avatarLetterChanged() && !hasAvatar) {
            this._root.firstChild.textContent = vm.avatarLetter;
        }
    }
}

/**
 * @param  {Object} vm   view model with {avatarUrl, avatarColorNumber, avatarTitle, avatarLetter}
 * @param  {Number} size
 * @return {Element}
 */
export function renderStaticAvatar(vm, size, extraClasses = undefined) {
    const hasAvatar = !!vm.avatarUrl(size);
    let avatarClasses = classNames({
        avatar: true,
        [`size-${size}`]: true,
        [`usercolor${vm.avatarColorNumber}`]: !hasAvatar,
    });
    if (extraClasses) {
        avatarClasses += ` ${extraClasses}`;
    }
    const avatarContent = hasAvatar ? renderImg(vm, size) : text(vm.avatarLetter);
    return tag.div({className: avatarClasses}, [avatarContent]);
}

function renderImg(vm, size) {
    const sizeStr = size.toString();
    return tag.img({src: vm.avatarUrl(size), width: sizeStr, height: sizeStr, title: vm.avatarTitle});
}