// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
// See LICENSE.txt for license information.

import RNUtils from '@mattermost/rnutils';

import {View} from '@constants';
import {
    IMAGE_MAX_HEIGHT,
    IMAGE_MIN_DIMENSION,
    MAX_GIF_SIZE,
    VIEWPORT_IMAGE_ATTACHMENT_OFFSET,
    VIEWPORT_IMAGE_OFFSET,
    VIEWPORT_IMAGE_REPLY_OFFSET,
} from '@constants/image';

export const calculateDimensions = (height?: number, width?: number, viewPortWidth = 0, viewPortHeight = 0, matchViewPort?: boolean) => {
    'worklet';

    if (!height || !width) {
        return {
            height: 0,
            width: 0,
        };
    }

    const ratio = height / width;
    const heightRatio = width / height;

    let imageWidth = width;
    let imageHeight = height;

    if (width >= viewPortWidth) {
        imageWidth = viewPortWidth;
        imageHeight = imageWidth * ratio;
    } else if (width < IMAGE_MIN_DIMENSION) {
        imageWidth = IMAGE_MIN_DIMENSION;
        imageHeight = imageWidth * ratio;
    }

    if ((imageHeight > IMAGE_MAX_HEIGHT || (viewPortHeight && imageHeight > viewPortHeight)) && viewPortHeight <= IMAGE_MAX_HEIGHT) {
        imageHeight = viewPortHeight || IMAGE_MAX_HEIGHT;
        imageWidth = imageHeight * heightRatio;
    } else if (imageHeight < IMAGE_MIN_DIMENSION && IMAGE_MIN_DIMENSION * heightRatio <= viewPortWidth) {
        imageHeight = IMAGE_MIN_DIMENSION;
        imageWidth = imageHeight * heightRatio;
    } else if (viewPortHeight && imageHeight > viewPortHeight) {
        imageHeight = viewPortHeight;
        imageWidth = imageHeight * heightRatio;
    }

    if (
        matchViewPort &&
        width < viewPortWidth &&
        height < viewPortHeight
    ) {
        if (height > width) {
            // Portrait: fit to viewport height
            imageHeight = viewPortHeight;
            imageWidth = imageHeight * heightRatio;

            // Ensure width doesn't exceed viewport
            if (imageWidth > viewPortWidth) {
                imageWidth = viewPortWidth;
                imageHeight = imageWidth * ratio;
            }
        } else {
            // Landscape or square: fit to viewport width
            imageWidth = viewPortWidth;
            imageHeight = imageWidth * ratio;

            // Ensure height doesn't exceed viewport
            if (imageHeight > viewPortHeight) {
                imageHeight = viewPortHeight;
                imageWidth = imageHeight * heightRatio;
            }
        }
    }

    return {
        height: imageHeight,
        width: imageWidth,
    };
};

export function getViewPortWidth(isReplyPost: boolean, tabletOffset = false, imageAttachmentOffset = false) {
    const {width, height} = RNUtils.getWindowDimensions();
    let portraitPostWidth = Math.min(width, height) - VIEWPORT_IMAGE_OFFSET;

    if (tabletOffset) {
        portraitPostWidth -= View.TABLET_SIDEBAR_WIDTH;
    }

    if (isReplyPost) {
        portraitPostWidth -= VIEWPORT_IMAGE_REPLY_OFFSET;
    }

    if (imageAttachmentOffset) {
        portraitPostWidth -= VIEWPORT_IMAGE_ATTACHMENT_OFFSET;
    }

    return portraitPostWidth;
}

// isGifTooLarge returns true if we think that the GIF may cause the device to run out of memory when rendered
// based on the image's dimensions and frame count.
export function isGifTooLarge(imageMetadata?: PostImage) {
    if (imageMetadata?.format !== 'gif') {
        // Not a gif or from an older server that doesn't count frames
        return false;
    }

    const {frame_count: frameCount, height, width} = imageMetadata;

    // Try to estimate the in-memory size of the gif to prevent the device out of memory
    return width * height * (frameCount || 1) > MAX_GIF_SIZE;
}