/*
 * Copyright (C) 2016-2022  Yomichan Authors
 *
 * 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/>.
 */

/* global
 * DocumentUtil
 * FrameClient
 * ThemeController
 * dynamicLoader
 */

/**
 * This class is the container which hosts the display of search results.
 */
class Popup extends EventDispatcher {
    /**
     * Creates a new instance.
     * @param {object} details
     * @param {string} details.id The ID of the popup.
     * @param {number} details.depth The depth of the popup.
     * @param {number} details.frameId The ID of the host frame.
     * @param {boolean} details.childrenSupported Whether or not the popup is able to show child popups.
     */
    constructor({
        id,
        depth,
        frameId,
        childrenSupported
    }) {
        super();
        this._id = id;
        this._depth = depth;
        this._frameId = frameId;
        this._childrenSupported = childrenSupported;
        this._parent = null;
        this._child = null;
        this._injectPromise = null;
        this._injectPromiseComplete = false;
        this._visible = new DynamicProperty(false);
        this._visibleValue = false;
        this._options = null;
        this._optionsContext = null;
        this._contentScale = 1.0;
        this._targetOrigin = chrome.runtime.getURL('/').replace(/\/$/, '');

        this._frameSizeContentScale = null;
        this._frameClient = null;
        this._frame = document.createElement('iframe');
        this._frame.className = 'yomichan-popup';
        this._frame.style.width = '0';
        this._frame.style.height = '0';

        this._container = this._frame;
        this._shadow = null;

        this._themeController = new ThemeController(this._frame);

        this._fullscreenEventListeners = new EventListenerCollection();
    }

    /**
     * The ID of the popup.
     * @type {string}
     */
    get id() {
        return this._id;
    }

    /**
     * The parent of the popup.
     * @type {Popup}
     */
    get parent() {
        return this._parent;
    }

    /**
     * Sets the parent popup.
     * @param {Popup} value The parent popup to assign.
     */
    set parent(value) {
        this._parent = value;
    }

    /**
     * The child of the popup.
     * @type {Popup}
     */
    get child() {
        return this._child;
    }

    /**
     * Sets the child popup.
     * @param {Popup} value The child popup to assign.
     */
    set child(value) {
        this._child = value;
    }

    /**
     * The depth of the popup.
     * @type {numer}
     */
    get depth() {
        return this._depth;
    }

    /**
     * Gets the content window of the frame, which can be `null`
     * depending on the current state of the frame.
     * @type {?Window}
     */
    get frameContentWindow() {
        return this._frame.contentWindow;
    }

    /**
     * Gets the DOM node that contains the frame.
     * @type {Element}
     */
    get container() {
        return this._container;
    }

    /**
     * Gets the ID of the frame.
     * @type {number}
     */
    get frameId() {
        return this._frameId;
    }

    /**
     * Prepares the popup for use.
     */
    prepare() {
        this._frame.addEventListener('mouseover', this._onFrameMouseOver.bind(this));
        this._frame.addEventListener('mouseout', this._onFrameMouseOut.bind(this));
        this._frame.addEventListener('mousedown', (e) => e.stopPropagation());
        this._frame.addEventListener('scroll', (e) => e.stopPropagation());
        this._frame.addEventListener('load', this._onFrameLoad.bind(this));
        this._visible.on('change', this._onVisibleChange.bind(this));
        yomichan.on('extensionUnloaded', this._onExtensionUnloaded.bind(this));
        this._onVisibleChange({value: this.isVisibleSync()});
        this._themeController.prepare();
    }

    /**
     * Sets the options context for the popup.
     * @param {object} optionsContext The options context object.
     */
    async setOptionsContext(optionsContext) {
        await this._setOptionsContext(optionsContext);
        await this._invokeSafe('Display.setOptionsContext', {optionsContext});
    }

    /**
     * Hides the popup.
     * @param {boolean} changeFocus Whether or not the parent popup or host frame should be focused.
     */
    hide(changeFocus) {
        if (!this.isVisibleSync()) {
            return;
        }

        this._setVisible(false);
        if (this._child !== null) {
            this._child.hide(false);
        }
        if (changeFocus) {
            this._focusParent();
        }
    }

    /**
     * Returns whether or not the popup is currently visible.
     * @returns {Promise<boolean>} `true` if the popup is visible, `false` otherwise.
     */
    async isVisible() {
        return this.isVisibleSync();
    }

    /**
     * Force assigns the visibility of the popup.
     * @param {boolean} value Whether or not the popup should be visible.
     * @param {number} priority The priority of the override.
     * @returns {Promise<string?>} A token used which can be passed to `clearVisibleOverride`,
     *   or null if the override wasn't assigned.
     */
    async setVisibleOverride(value, priority) {
        return this._visible.setOverride(value, priority);
    }

    /**
     * Clears a visibility override that was generated by `setVisibleOverride`.
     * @param {string} token The token returned from `setVisibleOverride`.
     * @returns {Promise<boolean>} `true` if the override existed and was removed, `false` otherwise.
     */
    async clearVisibleOverride(token) {
        return this._visible.clearOverride(token);
    }

    /**
     * Checks whether a point is contained within the popup's rect.
     * @param {number} x The x coordinate.
     * @param {number} y The y coordinate.
     * @returns {Promise<boolean>} `true` if the point is contained within the popup's rect, `false` otherwise.
     */
    async containsPoint(x, y) {
        for (let popup = this; popup !== null && popup.isVisibleSync(); popup = popup.child) {
            const rect = popup.getFrameRect();
            if (rect.valid && x >= rect.x && y >= rect.y && x < rect.x + rect.width && y < rect.y + rect.height) {
                return true;
            }
        }
        return false;
    }

    /**
     * Shows and updates the positioning and content of the popup.
     * @param {{optionsContext: object, elementRect: {x: number, y: number, width: number, height: number}, writingMode: string}} details Settings for the outer popup.
     * @param {object} displayDetails The details parameter passed to `Display.setContent`; see that function for details.
     * @returns {Promise<void>}
     */
    async showContent(details, displayDetails) {
        if (this._options === null) { throw new Error('Options not assigned'); }

        const {optionsContext, elementRect, writingMode} = details;
        if (optionsContext !== null) {
            await this._setOptionsContextIfDifferent(optionsContext);
        }

        if (typeof elementRect !== 'undefined' && typeof writingMode !== 'undefined') {
            await this._show(elementRect, writingMode);
        }

        if (displayDetails !== null) {
            this._invokeSafe('Display.setContent', {details: displayDetails});
        }
    }

    /**
     * Sets the custom styles for the popup content.
     * @param {string} css The CSS rules.
     */
    setCustomCss(css) {
        this._invokeSafe('Display.setCustomCss', {css});
    }

    /**
     * Stops the audio auto-play timer, if one has started.
     */
    clearAutoPlayTimer() {
        this._invokeSafe('Display.clearAutoPlayTimer');
    }

    /**
     * Sets the scaling factor of the popup content.
     * @param {number} scale The scaling factor.
     */
    setContentScale(scale) {
        this._contentScale = scale;
        this._frame.style.fontSize = `${scale}px`;
        this._invokeSafe('Display.setContentScale', {scale});
    }

    /**
     * Returns whether or not the popup is currently visible, synchronously.
     * @returns {boolean} `true` if the popup is visible, `false` otherwise.
     */
    isVisibleSync() {
        return this._visible.value;
    }

    /**
     * Updates the outer theme of the popup.
     * @returns {Promise<void>}
     */
    async updateTheme() {
        this._themeController.updateTheme();
    }

    /**
     * Sets the custom styles for the outer popup container.
     * @param {string} css The CSS rules.
     * @param {boolean} useWebExtensionApi Whether or not web extension APIs should be used to inject the rules.
     *   When web extension APIs are used, a DOM node is not generated, making it harder to detect the changes.
     */
    async setCustomOuterCss(css, useWebExtensionApi) {
        let parentNode = null;
        const inShadow = (this._shadow !== null);
        if (inShadow) {
            useWebExtensionApi = false;
            parentNode = this._shadow;
        }
        const node = await dynamicLoader.loadStyle('yomichan-popup-outer-user-stylesheet', 'code', css, useWebExtensionApi, parentNode);
        this.trigger('customOuterCssChanged', {node, useWebExtensionApi, inShadow});
    }

    /**
     * Gets the rectangle of the DOM frame, synchronously.
     * @returns {{x: number, y: number, width: number, height: number, valid: boolean}} The rect.
     *   `valid` is `false` for `PopupProxy`, since the DOM node is hosted in a different frame.
     */
    getFrameRect() {
        const {left, top, width, height} = this._frame.getBoundingClientRect();
        return {x: left, y: top, width, height, valid: true};
    }

    /**
     * Gets the size of the DOM frame.
     * @returns {Promise<{width: number, height: number, valid: boolean}>} The size and whether or not it is valid.
     */
    async getFrameSize() {
        const {width, height} = this._frame.getBoundingClientRect();
        return {width, height, valid: true};
    }

    /**
     * Sets the size of the DOM frame.
     * @param {number} width The desired width of the popup.
     * @param {number} height The desired height of the popup.
     * @returns {Promise<boolean>} `true` if the size assignment was successful, `false` otherwise.
     */
    async setFrameSize(width, height) {
        this._setFrameSize(width, height);
        return true;
    }

    // Private functions

    _onFrameMouseOver() {
        this.trigger('framePointerOver', {});
    }

    _onFrameMouseOut() {
        this.trigger('framePointerOut', {});
    }

    _inject() {
        let injectPromise = this._injectPromise;
        if (injectPromise === null) {
            injectPromise = this._injectInner1();
            this._injectPromise = injectPromise;
            injectPromise.then(
                () => {
                    if (injectPromise !== this._injectPromise) { return; }
                    this._injectPromiseComplete = true;
                },
                () => {}
            );
        }
        return injectPromise;
    }

    async _injectInner1() {
        try {
            await this._injectInner2();
            return true;
        } catch (e) {
            this._resetFrame();
            if (e.source === this) { return false; } // Passive error
            throw e;
        }
    }

    async _injectInner2() {
        if (this._options === null) {
            throw new Error('Options not initialized');
        }

        const {useSecurePopupFrameUrl, usePopupShadowDom} = this._options.general;

        await this._setUpContainer(usePopupShadowDom);

        const setupFrame = (frame) => {
            frame.removeAttribute('src');
            frame.removeAttribute('srcdoc');
            this._observeFullscreen(true);
            this._onFullscreenChanged();
            const {contentDocument} = frame;
            if (contentDocument === null) {
                // This can occur when running inside a sandboxed frame without "allow-same-origin"
                const error = new Error('Popup not supoprted in this context');
                error.source = this; // Used to detect a passive error which should be ignored
                throw error;
            }
            const url = chrome.runtime.getURL('/popup.html');
            if (useSecurePopupFrameUrl) {
                contentDocument.location.href = url;
            } else {
                frame.setAttribute('src', url);
            }
        };

        const frameClient = new FrameClient();
        this._frameClient = frameClient;
        await frameClient.connect(this._frame, this._targetOrigin, this._frameId, setupFrame);

        // Configure
        await this._invokeSafe('Display.configure', {
            depth: this._depth,
            parentPopupId: this._id,
            parentFrameId: this._frameId,
            childrenSupported: this._childrenSupported,
            scale: this._contentScale,
            optionsContext: this._optionsContext
        });
    }

    _onFrameLoad() {
        if (!this._injectPromiseComplete) { return; }
        this._resetFrame();
    }

    _resetFrame() {
        const parent = this._container.parentNode;
        if (parent !== null) {
            parent.removeChild(this._container);
        }
        this._frame.removeAttribute('src');
        this._frame.removeAttribute('srcdoc');

        this._frameClient = null;
        this._injectPromise = null;
        this._injectPromiseComplete = false;
    }

    async _setUpContainer(usePopupShadowDom) {
        if (usePopupShadowDom && typeof this._frame.attachShadow === 'function') {
            const container = document.createElement('div');
            container.style.setProperty('all', 'initial', 'important');
            const shadow = container.attachShadow({mode: 'closed', delegatesFocus: true});
            shadow.appendChild(this._frame);

            this._container = container;
            this._shadow = shadow;
        } else {
            const frameParentNode = this._frame.parentNode;
            if (frameParentNode !== null) {
                frameParentNode.removeChild(this._frame);
            }

            this._container = this._frame;
            this._shadow = null;
        }

        await this._injectStyles();
    }

    async _injectStyles() {
        try {
            await this._injectPopupOuterStylesheet();
        } catch (e) {
            // NOP
        }

        try {
            await this.setCustomOuterCss(this._options.general.customPopupOuterCss, true);
        } catch (e) {
            // NOP
        }
    }

    async _injectPopupOuterStylesheet() {
        let fileType = 'file';
        let useWebExtensionApi = true;
        let parentNode = null;
        if (this._shadow !== null) {
            fileType = 'file-content';
            useWebExtensionApi = false;
            parentNode = this._shadow;
        }
        await dynamicLoader.loadStyle('yomichan-popup-outer-stylesheet', fileType, '/css/popup-outer.css', useWebExtensionApi, parentNode);
    }

    _observeFullscreen(observe) {
        if (!observe) {
            this._fullscreenEventListeners.removeAllEventListeners();
            return;
        }

        if (this._fullscreenEventListeners.size > 0) {
            // Already observing
            return;
        }

        DocumentUtil.addFullscreenChangeEventListener(this._onFullscreenChanged.bind(this), this._fullscreenEventListeners);
    }

    _onFullscreenChanged() {
        const parent = this._getFrameParentElement();
        if (parent !== null && this._container.parentNode !== parent) {
            parent.appendChild(this._container);
        }
    }

    async _show(elementRect, writingMode) {
        const injected = await this._inject();
        if (!injected) { return; }

        const optionsGeneral = this._options.general;
        const {popupDisplayMode} = optionsGeneral;
        const frame = this._frame;
        const frameRect = frame.getBoundingClientRect();

        const viewport = this._getViewport(optionsGeneral.popupScaleRelativeToVisualViewport);
        const scale = this._contentScale;
        const scaleRatio = this._frameSizeContentScale === null ? 1.0 : scale / this._frameSizeContentScale;
        this._frameSizeContentScale = scale;
        const getPositionArgs = [
            elementRect,
            Math.max(frameRect.width * scaleRatio, optionsGeneral.popupWidth * scale),
            Math.max(frameRect.height * scaleRatio, optionsGeneral.popupHeight * scale),
            viewport,
            scale,
            optionsGeneral,
            writingMode
        ];
        let [x, y, width, height, below] = (
            writingMode === 'horizontal-tb' || optionsGeneral.popupVerticalTextPosition === 'default' ?
            this._getPositionForHorizontalText(...getPositionArgs) :
            this._getPositionForVerticalText(...getPositionArgs)
        );

        frame.dataset.popupDisplayMode = popupDisplayMode;
        frame.dataset.below = `${below}`;

        if (popupDisplayMode === 'full-width') {
            x = viewport.left;
            y = below ? viewport.bottom - height : viewport.top;
            width = viewport.right - viewport.left;
        }

        frame.style.left = `${x}px`;
        frame.style.top = `${y}px`;
        this._setFrameSize(width, height);

        this._setVisible(true);
        if (this._child !== null) {
            this._child.hide(true);
        }
    }

    _setFrameSize(width, height) {
        const {style} = this._frame;
        style.width = `${width}px`;
        style.height = `${height}px`;
    }

    _setVisible(visible) {
        this._visible.defaultValue = visible;
    }

    _onVisibleChange({value}) {
        if (this._visibleValue === value) { return; }
        this._visibleValue = value;
        this._frame.style.setProperty('visibility', value ? 'visible' : 'hidden', 'important');
        this._invokeSafe('Display.visibilityChanged', {value});
    }

    _focusParent() {
        if (this._parent !== null) {
            // Chrome doesn't like focusing iframe without contentWindow.
            const contentWindow = this._parent.frameContentWindow;
            if (contentWindow !== null) {
                contentWindow.focus();
            }
        } else {
            // Firefox doesn't like focusing window without first blurring the iframe.
            // this._frame.contentWindow.blur() doesn't work on Firefox for some reason.
            this._frame.blur();
            // This is needed for Chrome.
            window.focus();
        }
    }

    async _invoke(action, params={}) {
        const contentWindow = this._frame.contentWindow;
        if (this._frameClient === null || !this._frameClient.isConnected() || contentWindow === null) { return; }

        const message = this._frameClient.createMessage({action, params});
        return await yomichan.crossFrame.invoke(this._frameClient.frameId, 'popupMessage', message);
    }

    async _invokeSafe(action, params={}, defaultReturnValue) {
        try {
            return await this._invoke(action, params);
        } catch (e) {
            if (!yomichan.isExtensionUnloaded) { throw e; }
            return defaultReturnValue;
        }
    }

    _invokeWindow(action, params={}) {
        const contentWindow = this._frame.contentWindow;
        if (this._frameClient === null || !this._frameClient.isConnected() || contentWindow === null) { return; }

        const message = this._frameClient.createMessage({action, params});
        contentWindow.postMessage(message, this._targetOrigin);
    }

    _onExtensionUnloaded() {
        this._invokeWindow('Display.extensionUnloaded');
    }

    _getFrameParentElement() {
        let defaultParent = document.body;
        if (defaultParent !== null && defaultParent.tagName.toLowerCase() === 'frameset') {
            defaultParent = document.documentElement;
        }
        const fullscreenElement = DocumentUtil.getFullscreenElement();
        if (
            fullscreenElement === null ||
            fullscreenElement.shadowRoot ||
            fullscreenElement.openOrClosedShadowRoot // Available to Firefox 63+ for WebExtensions
        ) {
            return defaultParent;
        }

        switch (fullscreenElement.nodeName.toUpperCase()) {
            case 'IFRAME':
            case 'FRAME':
                return defaultParent;
        }

        return fullscreenElement;
    }

    _getPositionForHorizontalText(elementRect, width, height, viewport, offsetScale, optionsGeneral) {
        const preferBelow = (optionsGeneral.popupHorizontalTextPosition === 'below');
        const horizontalOffset = optionsGeneral.popupHorizontalOffset * offsetScale;
        const verticalOffset = optionsGeneral.popupVerticalOffset * offsetScale;

        const [x, w] = this._getConstrainedPosition(
            elementRect.x + elementRect.width - horizontalOffset,
            elementRect.x + horizontalOffset,
            width,
            viewport.left,
            viewport.right,
            true
        );
        const [y, h, below] = this._getConstrainedPositionBinary(
            elementRect.y - verticalOffset,
            elementRect.y + elementRect.height + verticalOffset,
            height,
            viewport.top,
            viewport.bottom,
            preferBelow
        );
        return [x, y, w, h, below];
    }

    _getPositionForVerticalText(elementRect, width, height, viewport, offsetScale, optionsGeneral, writingMode) {
        const preferRight = this._isVerticalTextPopupOnRight(optionsGeneral.popupVerticalTextPosition, writingMode);
        const horizontalOffset = optionsGeneral.popupHorizontalOffset2 * offsetScale;
        const verticalOffset = optionsGeneral.popupVerticalOffset2 * offsetScale;

        const [x, w] = this._getConstrainedPositionBinary(
            elementRect.x - horizontalOffset,
            elementRect.x + elementRect.width + horizontalOffset,
            width,
            viewport.left,
            viewport.right,
            preferRight
        );
        const [y, h, below] = this._getConstrainedPosition(
            elementRect.y + elementRect.height - verticalOffset,
            elementRect.y + verticalOffset,
            height,
            viewport.top,
            viewport.bottom,
            true
        );
        return [x, y, w, h, below];
    }

    _isVerticalTextPopupOnRight(positionPreference, writingMode) {
        switch (positionPreference) {
            case 'before':
                return !this._isWritingModeLeftToRight(writingMode);
            case 'after':
                return this._isWritingModeLeftToRight(writingMode);
            case 'left':
                return false;
            case 'right':
                return true;
            default:
                return false;
        }
    }

    _isWritingModeLeftToRight(writingMode) {
        switch (writingMode) {
            case 'vertical-lr':
            case 'sideways-lr':
                return true;
            default:
                return false;
        }
    }

    _getConstrainedPosition(positionBefore, positionAfter, size, minLimit, maxLimit, after) {
        size = Math.min(size, maxLimit - minLimit);

        let position;
        if (after) {
            position = Math.max(minLimit, positionAfter);
            position = position - Math.max(0, (position + size) - maxLimit);
        } else {
            position = Math.min(maxLimit, positionBefore) - size;
            position = position + Math.max(0, minLimit - position);
        }

        return [position, size, after];
    }

    _getConstrainedPositionBinary(positionBefore, positionAfter, size, minLimit, maxLimit, after) {
        const overflowBefore = minLimit - (positionBefore - size);
        const overflowAfter = (positionAfter + size) - maxLimit;

        if (overflowAfter > 0 || overflowBefore > 0) {
            after = (overflowAfter < overflowBefore);
        }

        let position;
        if (after) {
            size -= Math.max(0, overflowAfter);
            position = Math.max(minLimit, positionAfter);
        } else {
            size -= Math.max(0, overflowBefore);
            position = Math.min(maxLimit, positionBefore) - size;
        }

        return [position, size, after];
    }

    _getViewport(useVisualViewport) {
        const visualViewport = window.visualViewport;
        if (visualViewport !== null && typeof visualViewport === 'object') {
            const left = visualViewport.offsetLeft;
            const top = visualViewport.offsetTop;
            const width = visualViewport.width;
            const height = visualViewport.height;
            if (useVisualViewport) {
                return {
                    left,
                    top,
                    right: left + width,
                    bottom: top + height
                };
            } else {
                const scale = visualViewport.scale;
                return {
                    left: 0,
                    top: 0,
                    right: Math.max(left + width, width * scale),
                    bottom: Math.max(top + height, height * scale)
                };
            }
        }

        return {
            left: 0,
            top: 0,
            right: window.innerWidth,
            bottom: window.innerHeight
        };
    }

    async _setOptionsContext(optionsContext) {
        this._optionsContext = optionsContext;
        this._options = await yomichan.api.optionsGet(optionsContext);
        const {general} = this._options;
        this._themeController.theme = general.popupTheme;
        this._themeController.outerTheme = general.popupOuterTheme;
        this.updateTheme();
    }

    async _setOptionsContextIfDifferent(optionsContext) {
        if (deepEqual(this._optionsContext, optionsContext)) { return; }
        await this._setOptionsContext(optionsContext);
    }
}