import * as path from 'path';
import { utils } from '../core';
import { Resource } from 'resource-loader';
import { BitmapText } from '../extras';

/**
 * Register a BitmapText font from loader resource.
 *
 * @function parseBitmapFontData
 * @memberof PIXI.loaders
 * @param {PIXI.loaders.Resource} resource - Loader resource.
 * @param {PIXI.Texture|PIXI.Texture[]} textures - List of textures for each page.
 */
export function parse(resource, textures)
{
    resource.bitmapFont = BitmapText.registerFont(resource.data, textures);
}

export default function ()
{
    return function bitmapFontParser(resource, next)
    {
        // skip if no data or not xml data
        if (!resource.data || resource.type !== Resource.TYPE.XML)
        {
            next();

            return;
        }

        // skip if not bitmap font data, using some silly duck-typing
        if (resource.data.getElementsByTagName('page').length === 0
            || resource.data.getElementsByTagName('info').length === 0
            || resource.data.getElementsByTagName('info')[0].getAttribute('face') === null
        )
        {
            next();

            return;
        }

        let xmlUrl = !resource.isDataUrl ? path.dirname(resource.url) : '';

        if (resource.isDataUrl)
        {
            if (xmlUrl === '.')
            {
                xmlUrl = '';
            }

            if (this.baseUrl && xmlUrl)
            {
                // if baseurl has a trailing slash then add one to xmlUrl so the replace works below
                if (this.baseUrl.charAt(this.baseUrl.length - 1) === '/')
                {
                    xmlUrl += '/';
                }
            }
        }

        // remove baseUrl from xmlUrl
        xmlUrl = xmlUrl.replace(this.baseUrl, '');

        // if there is an xmlUrl now, it needs a trailing slash. Ensure that it does if the string isn't empty.
        if (xmlUrl && xmlUrl.charAt(xmlUrl.length - 1) !== '/')
        {
            xmlUrl += '/';
        }

        const pages = resource.data.getElementsByTagName('page');
        const textures = [];
        const loadOptions = {
            crossOrigin: resource.crossOrigin,
            loadType: Resource.LOAD_TYPE.IMAGE,
            metadata: resource.metadata.imageMetadata,
            parentResource: resource,
        };

        for (let x = 0; x < pages.length; ++x)
        {
            const textureUrl = xmlUrl + pages[x].getAttribute('file');

            if (utils.TextureCache[textureUrl])
            {
                textures.push(utils.TextureCache[textureUrl]);
            }
            else
            {
                // load the texture for the font
                this.add(`${resource.name}_image${x}`, textureUrl, loadOptions, () =>
                {
                    const nextTextures = [];

                    for (let x = 0; x < pages.length; ++x)
                    {
                        const nextTextureUrl = xmlUrl + pages[x].getAttribute('file');

                        if (utils.TextureCache[nextTextureUrl])
                        {
                            nextTextures.push(utils.TextureCache[nextTextureUrl]);
                        }
                        else
                        {
                            return;
                        }
                    }
                    parse(resource, nextTextures);
                    next();
                });
            }
        }

        if (textures.length === pages.length)
        {
            parse(resource, textures);
            next();
        }
    };
}